{"id":815,"date":"2024-12-29T22:41:07","date_gmt":"2024-12-29T14:41:07","guid":{"rendered":"https:\/\/blog.sssn.tech\/?p=815"},"modified":"2024-12-31T01:14:35","modified_gmt":"2024-12-30T17:14:35","slug":"%e5%85%a8%e7%a8%8b%e5%ad%a6%e4%b9%a0%e7%ac%94%e8%ae%b0%e8%ae%a1%e7%ae%97%e6%9c%ba%e7%bd%91%e7%bb%9c","status":"publish","type":"post","link":"https:\/\/blog.sssn.tech\/?p=815","title":{"rendered":"[\u5168\u7a0b\u5b66\u4e60\u7b14\u8bb0]-\u8ba1\u7b97\u673a\u7f51\u7edc"},"content":{"rendered":"<h1>\u8ba1\u7b97\u673a\u7f51\u7edc(\u81ea\u9876\u5411\u4e0b\u65b9\u6cd5) \u7b2c7\u7248 James F.Kurose\u7b49<\/h1>\n<p>\u672c\u7b14\u8bb0\u4e3b\u8981\u5185\u5bb9\u662fb\u7ad9\u7f51\u8bfe<a href=\"https:\/\/www.bilibili.com\/video\/BV1JV411t7ow\">\u4e2d\u79d1\u5927\u90d1\u70c7\u3001\u6768\u575a\u5168\u5957\u300a\u8ba1\u7b97\u673a\u7f51\u7edc\uff08\u81ea\u9876\u5411\u4e0b\u65b9\u6cd5 \u7b2c7\u7248\uff0cJames F.Kurose\uff0cKeith W.Ross\uff09\u300b\u8bfe\u7a0b<\/a>\u7684\u540c\u6b65\u5b66\u4e60\u8fc7\u7a0b, \u7cbe\u7b80\u4e86\u95f2\u804a\u5185\u5bb9, \u8f85\u4ee5\u8bfe\u7a0bPPT, \u6559\u6750\u539f\u6587, \u4e2a\u4eba\u7406\u89e3, \u5b66\u4e60\u901a\u8bfe\u540e\u4f5c\u4e1a, GPT\u89e3\u91ca\u7b49\u591a\u65b9\u9762\u6269\u5c55<\/p>\n<p>\u7f51\u8bfe\u6574\u4f53\u8bb2\u7684\u8282\u594f\u6bd4\u8f83\u6162, \u5efa\u8bae1.5\u500d\u901f\u542c, \u4e2d\u95f4\u4e2a\u522b\u5730\u65b9\u6bd4\u8f83\u5570\u55e6, \u770bPPT\u61c2\u4e86\u7684\u5730\u65b9\u53ef\u4ee5\u5feb\u8fdb<\/p>\n<h2>\u8bfe\u7a0b\u4e3b\u8981\u5185\u5bb9\u4ecb\u7ecd<\/h2>\n<ul>\n<li>\u8ba1\u7b97\u673a\u7f51\u7edc\u548c\u4e92\u8054\u7f51(\u91cd\u8981)<\/li>\n<li>\u5e94\u7528\u5c42<\/li>\n<li>\u4f20\u8f93\u5c42<\/li>\n<li>\u7f51\u7edc\u5c42: \u6570\u636e\u5e73\u9762<\/li>\n<li>\u7f51\u7edc\u5c42: \u63a7\u5236\u5e73\u9762<\/li>\n<li>\u6570\u636e\u94fe\u8def\u5c42\u548c\u5c40\u57df\u7f51<\/li>\n<li>\u7f51\u7edc\u5b89\u5168<\/li>\n<li>\u65e0\u7ebf\u548c\u79fb\u52a8\u7f51\u7edc<\/li>\n<li>\u591a\u5a92\u4f53\u7f51\u7edc<\/li>\n<li>\u7f51\u7edc\u7ba1\u7406<\/li>\n<\/ul>\n<h1>Chap1. \u8ba1\u7b97\u673a\u7f51\u7edc\u6982\u8ff0<\/h1>\n<h3>\u76ee\u6807<\/h3>\n<ul>\n<li>\u4e86\u89e3\u57fa\u672c\u672f\u8bed\u548c\u6982\u5ff5<\/li>\n<li>\u638c\u63e1\u7f51\u7edc\u57fa\u672c\u539f\u7406<\/li>\n<\/ul>\n<h2>1.1 \u4ec0\u4e48\u662fInternet<\/h2>\n<h3>\u4ece\u5177\u4f53\u6784\u6210\u7684\u89d2\u5ea6<\/h3>\n<p>\u8282\u70b9: <\/p>\n<ul>\n<li>\u4e3b\u673a\u53ca\u5176\u4e0a\u8fd0\u884c\u7684\u5e94\u7528\u7a0b\u5e8f<\/li>\n<li>\u8def\u7531\u5668, \u4ea4\u6362\u673a\u7b49\u7f51\u7edc\u4ea4\u6362\u8bbe\u5907<\/li>\n<\/ul>\n<p>\u5706\u5f62\u8868\u793a<strong>\u7f51\u7edc\u6838\u5fc3\u7cfb\u7edf<\/strong>: \u4ea4\u6362\u673a, \u8def\u7531\u5668<\/p>\n<p>\u65b9\u5f62\u8868\u793a<strong>\u8fb9\u7f18\u7cfb\u7edf<\/strong>: PC, \u670d\u52a1\u5668, \u624b\u673a, &#8230;<\/p>\n<p>\u8fde\u63a5\u8fd9\u4e24\u90e8\u5206\u7684\u8fb9\u53eb\u505a<strong>\u63a5\u5165\u7cfb\u7edf<\/strong><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241201164901183.png\" alt=\"image-20241201164901183\" style=\"zoom:40%;\" \/><\/p>\n<p>\u8fb9: \u901a\u8baf\u94fe\u8def<\/p>\n<ul>\n<li>\n<p>\u63a5\u5165\u7f51\u94fe\u8def: \u4e3b\u673a\u5230\u4e92\u8054\u7f51<\/p>\n<\/li>\n<li>\n<p>\u4e3b\u5e72\u94fe\u8def: \u8def\u7531\u5668\u95f4\u7684\u94fe\u8def<\/p>\n<\/li>\n<\/ul>\n<p>\u534f\u8bae:\u5bf9\u7b49\u5c42\u5b9e\u4f53\u5728\u901a\u4fe1\u8fc7\u7a0b\u4e2d\u5e94\u8be5\u9075\u5b88\u7684\u89c4\u5219\u7684\u96c6\u5408, \u534f\u8bae\u89c4\u5b9a\u4e86:<\/p>\n<ul>\n<li>\u8bed\u6cd5<\/li>\n<li>\u8bed\u4e49<\/li>\n<li>\u65f6\u5e8f<\/li>\n<li>\u52a8\u4f5c<\/li>\n<\/ul>\n<p>\u4e92\u8054\u7f51\u662f\u4ee5ICP\/IP\u4e3a\u4e3b\u7684\u4e00\u7c07\u534f\u8bae, \u4e92\u8054\u7f51\u662f\u7f51\u7edc\u7684\u7f51\u7edc<\/p>\n<ul>\n<li>\u7ed3\u6784\u677e\u6563, ISP\u4e92\u8054<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241130154758910.png\" alt=\"image-20241130154758910\" \/><\/p>\n<p>\u4e92\u8054\u7f51\u6709\u591a\u79cd\u8282\u70b9(\u7aef\u7cfb\u7edf): PC, \u670d\u52a1\u5668, \u624b\u673a, \u8def\u7531\u5668, \u667a\u80fd\u5bb6\u5177&#8230;<\/p>\n<p>\u591a\u79cd\u901a\u8baf\u94fe\u8def: \u5149\u7ebf, \u540c\u8f74\u7535\u7f06, \u65e0\u7ebf\u7535, \u536b\u661f&#8230;<\/p>\n<h3>\u4ece\u670d\u52a1\u7684\u89d2\u5ea6<\/h3>\n<p>\u4e92\u8054\u7f51\u662f \u5206\u5e03\u5f0f\u7684\u5e94\u7528\u8fdb\u7a0b(Web, VoIP, Email&#8230;)\u548c\u4e3a\u5206\u5e03\u5f0f\u5f15\u7528\u8fdb\u7a0b\u63d0\u4f9b\u670d\u52a1\u7684\u57fa\u7840\u8bbe\u65bd<\/p>\n<ul>\n<li>\u5206\u5e03\u5f0f\u5e94\u7528\u662f\u7f51\u7edc\u5b58\u5728\u7684\u7406\u7531<\/li>\n<li>\u57fa\u7840\u8bbe\u65bd\u5411\u5e94\u7528\u8fdb\u7a0b\u63d0\u4f9b\u901a\u4fe1\u670d\u52a1\n<ul>\n<li>\u9762\u5411\u94fe\u63a5\u7684\u670d\u52a1: TCP\/IP<\/li>\n<li>\u65e0\u94fe\u63a5\u7684\u670d\u52a1: UDP<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2>1.2 \u7f51\u7edc\u8fb9\u7f18<\/h2>\n<p>\u5206\u5e03\u5f0f\u5e94\u7528\u7a0b\u5e8f\u8fd0\u884c\u5728\u7f51\u7edc\u8fb9\u7f18<\/p>\n<p>\u8fb9\u7f18\u901a\u8fc7\u63a5\u5165\u8fde\u63a5\u5230\u7f51\u7edc\u6838\u5fc3, \u6838\u5fc3\u7684\u4f5c\u7528\u662f\u6570\u636e\u4ea4\u6362, \u8d1f\u8d23\u4efb\u610f\u4e24\u4e2a\u8fb9\u7f18\u7684\u901a\u4fe1<\/p>\n<p>\u7f51\u7edc\u5e94\u7528\u4ee5\u4e0b\u7684\u6240\u6709\u4e1c\u897f\u90fd\u662f\u57fa\u7840\u8bbe\u65bd, \u5305\u62ec\u7aef\u7cfb\u7edf, \u63a5\u5165, \u8def\u7531\u5668, \u4ea4\u6362\u673a\u7b49\u7b49<\/p>\n<ul>\n<li><strong>\u5ba2\u6237\/\u670d\u52a1\u5668\u6a21\u5f0f<\/strong>\n<ul>\n<li>\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u8bf7\u6c42\u670d\u52a1, \u670d\u52a1\u5668\u63d0\u4f9b<\/li>\n<li>\u6bd4\u5982Web\u6d4f\u89c8\u5668, Email\u5ba2\u6237\u7aef\/\u670d\u52a1\u5668<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u5bf9\u7b49\u6a21\u5f0f<\/strong>\n<ul>\n<li>\u5f88\u5c11(\u751a\u81f3\u6ca1\u6709)\u4e13\u7528\u670d\u52a1\u5668<\/li>\n<li>\u6bd4\u5982Gnutella, KaZaA<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2>1.3 \u7f51\u7edc\u6838\u5fc3<\/h2>\n<p>\u7f51\u7edc\u6838\u5fc3\u662f\u8def\u7531\u5668\u7684\u7f51\u72b6\u7f51\u7edc<\/p>\n<p>\u4e24\u79cd\u65b9\u5f0f<\/p>\n<ul>\n<li><strong>\u7535\u8def\u4ea4\u6362(\u7ebf\u8def\u4ea4\u6362)<\/strong>: \u6bcf\u4e2a\u547c\u53eb\u9884\u7559\u4e00\u6761\u4e13\u6709\u7ebf\u8def, \u6bd4\u5982\u7535\u8bdd\u7f51<\/li>\n<li><strong>\u5206\u7ec4\u4ea4\u6362<\/strong>:\n<ul>\n<li>\u5c06\u8981\u4f20\u9001\u7684\u6570\u636e\u5206\u6210\u4e00\u4e2a\u4e2a\u5355\u4f4d: \u7ec4<\/li>\n<li>\u5c06\u5206\u7ec4\u4ece\u4e00\u4e2a\u8def\u7531\u5668\u4f20\u5230\u76f8\u90bb\u8def\u7531\u5668(\u8df3, hop), \u4e00\u6bb5\u6bb5\u6700\u7ec8\u4ece\u6e90\u4f20\u5230\u76ee\u6807\u7aef<\/li>\n<li>\u6bcf\u6bb5: \u94fe\u8def\u6700\u5927\u4f20\u8f93\u80fd\u529b(\u5e26\u5bbd)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>\u7535\u8def\u4ea4\u6362(\u7ebf\u8def\u4ea4\u6362)<\/h3>\n<p>\u7aef\u5230\u7aef\u7684\u8d44\u6e90\u88ab\u5206\u914d\u7ed9\u4ece\u6e90\u5230\u76ee\u6807\u7684\u547c\u53eb(call)<\/p>\n<ul>\n<li>\u901a\u5e38\u88ab\u4f20\u7edf\u7535\u8bdd\u7f51\u7edc\u91c7\u7528<\/li>\n<li>\u72ec\u5360\u8d44\u6e90, \u4e0d\u5171\u4eab, \u4fdd\u8bc1\u4e86\u6027\u80fd<\/li>\n<li>\u5982\u679c\u547c\u53eb\u6ca1\u6709\u6570\u636e\u53d1\u9001, \u5219\u88ab\u5206\u914d\u5230\u8d44\u6e90\u88ab\u6d6a\u8d39<\/li>\n<li>\u4ea4\u6362\u8282\u70b9\u4e4b\u95f4\u94fe\u8def\u8f83\u7c97, \u5e26\u5bbd\u8f83\u5927\n<ul>\n<li>\u5c06\u7f51\u7edc\u8d44\u6e90\u5206\u6210\u7247(pieces), \u4e3a\u547c\u53eb\u5206\u914d\u7247<\/li>\n<li>\u6bd4\u5982\u9891\u5206, \u65f6\u5206, \u6ce2\u5206<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241201183942054.png\" alt=\"image-20241201183942054\" \/><\/p>\n<p>\u7535\u8def\u4ea4\u6362\u4e0d\u9002\u5408\u8ba1\u7b97\u673a\u4e4b\u95f4\u7684\u901a\u4fe1<\/p>\n<ul>\n<li>\u8fde\u63a5\u5efa\u7acb\u65f6\u95f4\u957f<\/li>\n<li>\u8ba1\u7b97\u673a\u901a\u4fe1\u6709\u7a81\u53d1\u6027, \u9020\u6210\u8d44\u6e90\u6d6a\u8d39<\/li>\n<li>\u53ef\u9760\u6027\u4e0d\u9ad8?\n<ul>\n<li>\u6838\u5fc3\u8282\u70b9\u635f\u6bc1\u5bfc\u81f4\u5168\u90e8\u901a\u4fe1\u5931\u6548<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>\u5206\u7ec4\u4ea4\u6362<\/h3>\n<p>\u4ee5\u5206\u7ec4(packet)\u4e3a\u5355\u4f4d\u5b58\u50a8-\u8f6c\u53d1\u65b9\u5f0f<\/p>\n<ul>\n<li>\n<p>\u901a\u8baf\u8d44\u6e90\u4e0d\u7ec6\u5206\u4e3a\u7247, \u4f7f\u7528\u5168\u90e8\u5e26\u5bbd<\/p>\n<\/li>\n<li>\n<p>\u6570\u636e\u5206\u4e3apacket, \u4e00\u4e2a\u7ec4\u88ab\u4f20\u8f93\u5230\u4e0b\u4e00\u4e2a\u94fe\u8def\u4e4b\u524d, \u5fc5\u987b\u5168\u90e8\u5230\u8fbe\u8def\u7531\u5668<\/p>\n<\/li>\n<li>\n<p>\u4e00\u6b21\u4f7f\u7528\u4e00\u6bb5\u94fe\u8def, \u5176\u4ed6\u94fe\u8def\u53ef\u4ee5\u5171\u4eab, \u6309\u9700\u4f7f\u7528<\/p>\n<\/li>\n<li>\n<p>\u5ef6\u8fdf\u6bd4\u7535\u8def\u4ea4\u6362\u66f4\u5927, \u6362\u53d6\u4e86\u5171\u4eab\u6027<\/p>\n<\/li>\n<\/ul>\n<p>\u5982\u679c\u5230\u8fbe\u8def\u7531\u5668\u7684\u901f\u7387&gt;\u8def\u7531\u5668\u4f20\u51fa\u7684\u901f\u7387:<\/p>\n<ul>\n<li>\u5206\u7ec4\u4f1a\u6392\u961f\u7b49\u5f85\u4f20\u8f93<\/li>\n<li>\u8d85\u51fa\u8def\u7531\u5668\u7f13\u5b58\u7684\u4f1a\u88ab\u629b\u5f03<\/li>\n<\/ul>\n<p>\u8def\u7531: \u51b3\u5b9a\u5206\u7ec4\u91c7\u7528\u7684\u6e90\u5230\u76ee\u6807\u7684\u8def\u5f84, \u7b97\u51fa\u8def\u7531\u8868<\/p>\n<p>\u8f6c\u53d1: \u67e5\u8def\u7531\u8868\u5c06\u5206\u7ec4\u4ece\u8def\u7531\u5668\u7684\u8f93\u5165\u94fe\u8def\u8f6c\u79fb\u5230\u8f93\u51fa\u94fe\u8def<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241201205107415.png\" alt=\"image-20241201205107415\" style=\"zoom:66%;\" \/><\/p>\n<p>\u5206\u7ec4\u4ea4\u6362\u4e8b\u5b9e\u4e0a\u662f<strong>\u7edf\u8ba1\u591a\u8def\u590d\u7528<\/strong>, \u672c\u8d28\u4e0a\u8fd8\u662f\u5212\u5206\u65f6\u95f4\u7247, \u4f46\u662f\u5212\u5206\u65b9\u6cd5\u662f\u52a8\u6001\u7684, \u662f\u7279\u6b8a\u7684\u65f6\u5206<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241201205245785.png\" alt=\"image-20241201205245785\" style=\"zoom:67%;\" \/><\/p>\n<p>\u591a\u5a92\u4f53\u5e94\u7528\u5e38\u5e38\u9700\u8981\u4fdd\u8bc1\u5e26\u5bbd, \u9700\u8981\u5206\u7ec4\u4ea4\u6362\u8868\u73b0\u51fa\u7ebf\u8def\u4ea4\u6362\u7684\u7279\u6027\u6765<\/p>\n<p>\u6570\u636e\u62a5\u65b9\u5f0f<\/p>\n<ul>\n<li>\n<p>\u6bcf\u4e2a\u5206\u7ec4\u76f8\u4e92\u72ec\u7acb<\/p>\n<\/li>\n<li>\n<p>\u5206\u7ec4\u5185\u5305\u542b\u76ee\u6807\u5b8c\u6574\u5730\u5740<\/p>\n<\/li>\n<li>\n<p>\u6ca1\u6709\u63e1\u624b<\/p>\n<\/li>\n<li>\n<p>\u4ea4\u6362\u8282\u70b9\u4e4b\u95f4\u4e0d\u7ef4\u62a4\u94fe\u63a5\u72b6\u6001<\/p>\n<\/li>\n<li>\n<p>\u7c7b\u4f3c\u4e8e\u5bc4\u4fe1<\/p>\n<\/li>\n<li>\n<p>\u4f20\u9001\u7ed9\u540c\u4e00\u4e2a\u76ee\u6807\u7684\u5206\u7ec4\u53ef\u80fd\u8d70\u4e0d\u540c\u7684\u8def(\u8def\u7531\u8868\u662f\u52a8\u6001\u7684)<\/p>\n<\/li>\n<\/ul>\n<p>\u865a\u7535\u8def\u65b9\u5f0f<\/p>\n<ul>\n<li>\u6709\u63e1\u624b, \u5efa\u7acb\u865a\u62df\u7ebf\u8def<\/li>\n<li>\u5efa\u7acb\u865a\u7535\u8def\u540e, \u6bcf\u4e2a\u4ea4\u6362\u8282\u70b9\u5b58\u50a8\u5bf9\u5e94\u7684\u8868\u9879(\u865a\u7535\u8def\u53f7-Next)<\/li>\n<li>\u5206\u7ec4\u5185\u5305\u542b\u865a\u7535\u8def\u53f7, \u4e0d\u6807\u8bc6\u76ee\u6807\u4e3b\u673a\u5b8c\u6574\u5730\u5740<\/li>\n<\/ul>\n<h3>\u5206\u7ec4\u4ea4\u6362-\u865a\u7535\u8def VS \u7535\u8def\u4ea4\u6362<\/h3>\n<p>\u4e8c\u8005\u867d\u7136\u6709\u76f8\u4f3c\u6027, \u4f46\u662f\u672c\u8d28\u4e0a\u662f\u4e0d\u540c\u7684\u6280\u672f<\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">\u7279\u6027<\/th>\n<th style=\"text-align: left;\">\u7535\u8def\u4ea4\u6362<\/th>\n<th style=\"text-align: left;\">\u865a\u7535\u8def\u65b9\u5f0f<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\"><strong>\u8fde\u63a5\u7c7b\u578b<\/strong><\/td>\n<td style=\"text-align: left;\">\u9762\u5411\u7269\u7406\u8fde\u63a5<\/td>\n<td style=\"text-align: left;\">\u9762\u5411\u903b\u8f91\u8fde\u63a5<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u8d44\u6e90\u5206\u914d<\/strong><\/td>\n<td style=\"text-align: left;\">\u72ec\u5360\u7269\u7406\u8d44\u6e90<\/td>\n<td style=\"text-align: left;\">\u52a8\u6001\u5171\u4eab\u8d44\u6e90<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u4f20\u8f93\u65b9\u5f0f<\/strong><\/td>\n<td style=\"text-align: left;\">\u8fde\u7eed\u6bd4\u7279\u6d41<\/td>\n<td style=\"text-align: left;\">\u6309\u5206\u7ec4\u4f20\u8f93<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u5efa\u7acb\u5ef6\u8fdf<\/strong><\/td>\n<td style=\"text-align: left;\">\u8f83\u9ad8\uff0c\u9700\u8981\u5efa\u7acb\u7269\u7406\u7535\u8def<\/td>\n<td style=\"text-align: left;\">\u8f83\u4f4e\uff0c\u4ec5\u9700\u5efa\u7acb\u903b\u8f91\u8fde\u63a5<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u4f20\u8f93\u6548\u7387<\/strong><\/td>\n<td style=\"text-align: left;\">\u8f83\u4f4e\uff0c\u53ef\u80fd\u5b58\u5728\u8d44\u6e90\u6d6a\u8d39<\/td>\n<td style=\"text-align: left;\">\u8f83\u9ad8\uff0c\u8d44\u6e90\u52a8\u6001\u5229\u7528<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>\u5bb9\u9519\u6027<\/strong><\/td>\n<td style=\"text-align: left;\">\u8f83\u5dee\uff0c\u6545\u969c\u9700\u91cd\u5efa\u8fde\u63a5<\/td>\n<td style=\"text-align: left;\">\u8f83\u9ad8\uff0c\u53ef\u52a8\u6001\u8c03\u6574\u8def\u5f84<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>1.4 \u63a5\u5165\u7f51, \u7269\u7406\u5a92\u4f53<\/h2>\n<p>\u524d\u9762\u4ecb\u7ecd\u4e86\u7f51\u7edc\u8fb9\u7f18, \u7f51\u7edc\u6838\u5fc3, \u8fd9\u91cc\u8ba8\u8bba\u5982\u4f55\u5c06\u8fb9\u7f18\u63a5\u5165\u7f51\u7edc<\/p>\n<h3>\u4f4f\u5b85\u63a5\u5165<\/h3>\n<ul>\n<li><strong>\u7535\u8bdd\u516c\u53f8<\/strong>: \u7528\u7535\u8bdd\u7ebf\u63a5\u5165, \u8c03\u5236\u89e3\u8c03\u5668, \u53e6\u4e00\u5934\u662f\u57ce\u63a7\u4ea4\u6362\u673a<\/li>\n<li><strong>\u6709\u7ebf\u7535\u89c6\u516c\u53f8<\/strong>: \u6539\u9020\u540c\u8f74\u7535\u7f06, \u5355\u5411\u6539\u53cc\u5411\n<ul>\n<li>FDM: \u4e0d\u540c\u9891\u6bb5\u4f20\u8f93\u4e0d\u540c\u6570\u636e<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u7535\u529b\u516c\u53f8<\/strong>: \u7535\u7ebf\u4e0a\u7f51<\/li>\n<\/ul>\n<h3>\u4f01\u4e1a\u63a5\u5165<\/h3>\n<ul>\n<li><strong>\u4ea4\u6362\u673a\u7ea7\u8054<\/strong><\/li>\n<\/ul>\n<p><strong>\u7269\u7406\u5a92\u4f53<\/strong>: \u5bfc\u5f15\u6027\u5a92\u4f53(\u6709\u5b9e\u4f53\u7684, \u53cc\u7ede\u7ebf, \u540c\u8f74\u7535\u7f06), \u975e\u5bfc\u5f15\u6027\u5a92\u4f53(\u6ca1\u5b9e\u4f53\u7684, \u65e0\u7ebf\u94fe\u8def)<\/p>\n<h2>1.5 Internet\/ISP\u7ed3\u6784<\/h2>\n<p>\u7aef\u7cfb\u7edf\u901a\u8fc7\u63a5\u5165ISP\u8bbf\u95ee\u4e92\u8054\u7f51<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241203101106255.png\" alt=\"image-20241203101106255\" style=\"zoom:50%;\" \/><\/p>\n<ul>\n<li><strong>ISP<\/strong>: \u63d0\u4f9b\u4e92\u8054\u7f51\u670d\u52a1, \u6bd4\u5982\u79fb\u52a8, \u4e2d\u56fd\u6559\u80b2\u7f51<\/li>\n<li><strong>ICP<\/strong>: \u63d0\u4f9b\u5185\u5bb9, \u6bd4\u5982\u767e\u5ea6, \u8c37\u6b4c\n<ul>\n<li>\u6709\u7684ICP\u4e0d\u6ee1ISP\u7684\u670d\u52a1, \u4f1a\u81ea\u5df1\u90e8\u7f72\u6570\u636e\u4e2d\u5fc3\u548c\u7ebf\u7f06<\/li>\n<\/ul>\n<\/li>\n<li><strong>IXP<\/strong>: \u5728ISP\u4e4b\u95f4\u4ea4\u6362\u6d41\u91cf, \u514d\u4e8e\u4ece\u9aa8\u5e72\u7f51\u7edc\u7ed5\u884c<\/li>\n<\/ul>\n<h3>Internet\u7ed3\u6784: \u7f51\u7edc\u7684\u7f51\u7edc<\/h3>\n<p>\u677e\u6563\u7684\u5c42\u6b21\u6a21\u578b<\/p>\n<h3>Tier 1 ISP, \u5982UUNet, BBN\/Genuity, Sprint, AT&amp;T<\/h3>\n<ul>\n<li>\u56fd\u5bb6\/\u56fd\u9645\u8986\u76d6\u7684\u9aa8\u5e72\u7f51\u7edc, \u901f\u7387\u6781\u9ad8<\/li>\n<li>\u4e0e\u5176\u4ed6\u7b2c\u4e00\u5c42ISP\u76f4\u63a5\u76f8\u8fde, \u514d\u8d39\u5bf9\u7b49\u4ea4\u6362\u6d41\u91cf<\/li>\n<li>\u4e3a\u5927\u91cf\u4e8c\u5c42ISP\u548c\u5927\u578b\u516c\u53f8, \u653f\u5e9c\u673a\u6784\u63d0\u4f9b\u63a5\u5165<\/li>\n<\/ul>\n<p>\u4e0b\u5c42\u7f51\u7edc\u901a\u8fc7POP\u63a5\u5165\u4e0a\u5c42\u7f51\u7edc<\/p>\n<h3>Tier 2 ISP<\/h3>\n<ul>\n<li>\n<p>\u901a\u5e38\u662f\u533a\u57df\u6027ISP, \u901a\u8fc7\u63a5\u5165Tier 1 ISP\u8bbf\u95ee\u5168\u7403\u4e92\u8054\u7f51<\/p>\n<\/li>\n<li>\n<p>\u5411Tier 1\u652f\u4ed8\u8d39\u7528, \u6709\u4e00\u5b9a\u4e0a\u6e38\u6210\u672c<\/p>\n<\/li>\n<li>\n<p>\u4e8c\u5c42ISP\u4e4b\u95f4\u4e5f\u901a\u8fc7IXP\u4e92\u8054<\/p>\n<\/li>\n<li>\n<p>\u4e3aTier 3 ISP, \u4f01\u4e1a, \u673a\u6784\u7b49\u63d0\u4f9b\u63a5\u5165<\/p>\n<\/li>\n<\/ul>\n<h3>Tier 3 ISP: local ISP<\/h3>\n<ul>\n<li>\n<p>\u901a\u5e38\u53ea\u8986\u76d6\u4e00\u4e2a\u57ce\u5e02, \u6216\u8005\u4e00\u4e2a\u5c0f\u533a\u57df<\/p>\n<\/li>\n<li>\n<p>\u76f4\u63a5\u5411\u5bb6\u5ead, \u5c0f\u578b\u4f01\u4e1a, \u672c\u5730\u673a\u6784\u63d0\u4f9b\u63a5\u5165<\/p>\n<\/li>\n<li>\n<p>\u901a\u5e38\u6ca1\u6709\u5bf9\u7b49\u5173\u7cfb, \u5b8c\u5168\u4f9d\u8d56\u4e0a\u6e38<\/p>\n<\/li>\n<\/ul>\n<h3>IXP: ISP\u4e4b\u95f4\u7684\u6d41\u91cf\u4ea4\u6362<\/h3>\n<ul>\n<li>\u4e3b\u8981\u7528\u4e8eTier 2, \u4e5f\u53ef\u80fd\u6d89\u53ca1\u6216\u80053<\/li>\n<li>\u4e3aTier 2 ISP\u5efa\u7acb\u516c\u5171\u5bf9\u7b49\u5173\u7cfb, \u5e2e\u52a9\u7ed5\u8fc7\u6602\u8d35\u7684Tier 1\u4e0a\u6e38\u5e26\u5bbd<\/li>\n<li>\u9664\u4e86ISP, IXP\u8fd8\u4e3aCDN, \u4f01\u4e1a\u7f51\u7edc, \u4e91\u670d\u52a1\u63d0\u4f9b\u670d\u52a1<\/li>\n<\/ul>\n<h2>1.6 \u6027\u80fd: \u4e22\u5305, \u5ef6\u8fdf, \u541e\u5410\u91cf<\/h2>\n<p>\u5206\u7ec4\u4e22\u5931\u548c\u5ef6\u65f6\u662f\u600e\u6837\u53d1\u751f\u7684<\/p>\n<ul>\n<li>\u8def\u7531\u5668\u6392\u961f\u5ef6\u8fdf\n<ul>\n<li>\u8fdb\u5165\u6392\u961f, \u9020\u6210\u5ef6\u8fdf<\/li>\n<li>\u961f\u4f0d\u5df2\u6ee1, \u76f4\u63a5\u4e22\u5f03<\/li>\n<\/ul>\n<\/li>\n<li>\u7269\u7406\u94fe\u8def\u4e0a\u7684\u4f20\u64ad\u5ef6\u8fdf\n<ul>\n<li>\u5149\u901f<\/li>\n<\/ul>\n<\/li>\n<li>\u8def\u7531\u5668\u7684\u5904\u7406\u5ef6\u8fdf\n<ul>\n<li>\u8def\u7531\u5668\u89e3\u6790\u5206\u7ec4\u5185\u5bb9, \u67e5\u8868, \u786e\u5b9a\u8def\u7531\u65b9\u5411<\/li>\n<\/ul>\n<\/li>\n<li>\u8def\u7531\u5668\u7684\u4f20\u8f93\u5ef6\u8fdf\n<ul>\n<li>$$T=\\frac{L}{R}$$<\/li>\n<li>L\u662f\u4e00\u4e2a\u5206\u7ec4\u7684\u5927\u5c0f, R\u662f\u8def\u7531\u5668\u5e26\u5bbd<\/li>\n<li>\u4ee3\u8868\u4e00\u4e2a\u5206\u7ec4\u7f13\u5b58\u4e0b\u6765\u7684\u5ef6\u8fdf<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u6d41\u91cf\u5f3a\u5ea6<br \/>\n$$<br \/>\nI = \\frac{La}{R}<br \/>\n$$<br \/>\n\u5176\u4e2d<\/p>\n<ul>\n<li>$$L$$\u662f\u4e00\u4e2a\u5206\u7ec4\u7684\u5927\u5c0f, bits<\/li>\n<li>$$R$$\u662f\u94fe\u8def\u5e26\u5bbd, bps<\/li>\n<li>$$a$$\u662f\u5206\u7ec4\u5230\u8fbe\u961f\u5217\u7684\u5e73\u5747\u901f\u7387(\u4e2a\u6570)<\/li>\n<\/ul>\n<p>$$I$$\u8d8b\u8fd1\u4e8e$$0$$, \u5e73\u5747\u6392\u961f\u5ef6\u65f6\u5f88\u5c0f<\/p>\n<p>$$I$$\u8d8b\u8fd1\u4e8e$$1$$, \u5e73\u5747\u6392\u961f\u5ef6\u65f6\u5f88\u5927<\/p>\n<p>$$I \\gt 1$$, \u6bd4\u7279\u5230\u8fbe\u961f\u5217\u7684\u6570\u636e\u8d85\u8fc7\u4e86\u8f93\u51fa\u901f\u7387, \u6392\u961f\u5ef6\u65f6\u65e0\u7a77\u5927, \u5728\u8bbe\u8ba1\u7cfb\u7edf\u65f6, \u5e94\u907f\u514d<\/p>\n<h3>TraceRoute<\/h3>\n<p>\u7528\u6765\u6d4b\u8bd5\u591a\u8df3\u4e4b\u95f4\u6bcf\u4e00\u8df3\u7684\u5ef6\u65f6<\/p>\n<p>TTL: Time to Live, IP\u534f\u8bae\u4e2d\u7684\u6570\u5b57\u5b57\u6bb5, \u8868\u793a\u6700\u5927\u5b58\u6d3b\u65f6\u95f4, \u901a\u5e38\u4ee5\u8df3\u8ba1<\/p>\n<p>TraceRoute\u4f1a\u5148\u53d1\u9001TTL=1\u7684\u6570\u636e\u5305, \u6570\u636e\u5305\u8fbe\u5230\u7b2c\u4e00\u8df3\u8def\u7531\u5668\u65f6, TTL=0\u88ab\u4e22\u5f03, \u5e76\u8fd4\u56de\u4e00\u4e2aICMP\u8d85\u65f6\u6d88\u606f, \u6d88\u606f\u4e2d\u5305\u542b\u7b2c\u4e00\u6761\u8def\u7531\u5668\u7684IP\u5730\u5740<\/p>\n<p>TraceRoute\u53d1\u9001TTL=2\u7684\u6570\u636e\u5305, \u63a2\u6d4b\u7b2c\u4e8c\u8df3\u670d\u52a1\u5668, \u4ee5\u6b64\u7c7b\u63a8<\/p>\n<p>TraceRoute\u901a\u5e38\u4f7f\u7528UDP\u6570\u636e\u5305<\/p>\n<h3>\u541e\u5410\u91cf<\/h3>\n<p>\u5728\u6e90\u548c\u76ee\u6807\u4e4b\u95f4\u4f20\u8f93\u7684\u901f\u7387(\u6570\u636e\u91cf\/\u5355\u4f4d\u65f6\u95f4)<\/p>\n<ul>\n<li>\u77ac\u95f4\u541e\u5410\u91cf<\/li>\n<li>\u5e73\u5747\u541e\u5410\u91cf<\/li>\n<\/ul>\n<h2>1.7 \u534f\u8bae\u5c42\u6b21, \u670d\u52a1\u6a21\u578b<\/h2>\n<p>\u7f51\u7edc\u662f\u8fc4\u4eca\u4e3a\u6b62\u4eba\u7c7b\u521b\u9020\u7684\u6700\u590d\u6742\u7684\u7cfb\u7edf, \u4e3a\u4e86\u5904\u7406\u590d\u6742\u7684\u529f\u80fd, \u9700\u8981\u5206\u5c42<\/p>\n<p>\u6bcf\u4e00\u5c42\u90fd\u901a\u8fc7\u63a5\u53e3\u548c\u4e0b\u4e00\u5c42\u4ea4\u6362PDU, \u4ee5\u4f7f\u7528\u4e0b\u4e00\u5c42\u63d0\u4f9b\u7684\u670d\u52a1, \u901a\u8fc7\u672c\u5c42\u7684\u5904\u7406\u540e, \u5411\u4e0a\u5c42\u63d0\u4f9b\u81ea\u5df1\u7684\u670d\u52a1<\/p>\n<ul>\n<li><strong>\u670d\u52a1<\/strong>: \u67d0\u4e00\u5c42\u53ef\u4ee5\u5411\u4e0a\u4e00\u5c42\u63d0\u4f9b\u7684\u529f\u80fd\u7684\u96c6\u5408<\/li>\n<li><strong>\u670d\u52a1\u8bbf\u95ee\u70b9<\/strong>: SAP(Service Access Point)\n<ul>\n<li>\u4e00\u4e2a\u5c42\u7528\u4ee5\u533a\u5206\u4e0d\u540c\u670d\u52a1\u7528\u6237\u7684\u70b9<\/li>\n<li>\u4f8b\u5982\u4f20\u8f93\u5c42\u7684SAP\u662f\u7aef\u53e3<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u539f\u8bed<\/strong>: primitive, \u4e0a\u5c42\u4f7f\u7528\u4e0b\u5c42\u670d\u52a1\u7684\u5f62\u5f0f\n<ul>\n<li>\u4e00\u4e2a\u5c42\u4f1a\u63d0\u4f9b\u591a\u79cd\u670d\u52a1, \u4e0a\u5c42\u4f7f\u7528\u7684\u5177\u4f53\u7684\u670d\u52a1, \u7a7f\u8fc7\u5c42\u95f4\u63a5\u53e3\u7684\u4f4d\u7f6e\u4e0a\u539f\u8bed <\/li>\n<li>socket api\u7684\u4e00\u7cfb\u5217\u51fd\u6570\u662f\u539f\u8bed<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u534f\u8bae<\/strong>: \u5bf9\u7b49\u5c42\u5b9e\u4f53\u5728\u4ea4\u4e92\u8fc7\u7a0b\u4e2d\u9700\u8981\u9075\u5b88\u7684\u89c4\u5219\u7684\u96c6\u5408<\/li>\n<\/ul>\n<h3>\u4e24\u79cd\u4e3b\u8981\u7c7b\u578b\u7684\u670d\u52a1<\/h3>\n<ul>\n<li><strong>\u9762\u5411\u8fde\u63a5\u7684\u670d\u52a1<\/strong>\n<ul>\n<li>\u4e24\u4e2a\u901a\u8baf\u7684\u5b9e\u4f53\u4f1a\u5efa\u7acb\u67d0\u79cd\u8fde\u63a5<\/li>\n<li>\u5148\u63e1\u624b, \u518d\u901a\u8baf, \u6700\u540e\u62c6\u9664\u8fde\u63a5<\/li>\n<li>\u975e\u96f6\u661f\u7684, \u5927\u6570\u636e\u5757, \u9700\u8981\u53ef\u9760<\/li>\n<li>\u901a\u5e38\u662f\u4fdd\u5e8f\u7684, \u4f46\u4e5f\u6709\u4f8b\u5916<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u65e0\u8fde\u63a5\u7684\u670d\u52a1<\/strong>\n<ul>\n<li>\u4e0d\u5efa\u7acb\u8fde\u63a5, \u4e0d\u9884\u7559\u8d44\u6e90, \u4e0d\u9700\u8981\u53cc\u65b9\u6d3b\u8dc3<\/li>\n<li>\u7c7b\u4f3c\u4e8e\u5bc4\u4fe1, \u76f4\u63a5\u901a\u8baf<\/li>\n<li>\u5c0f\u5757\u7684\u96f6\u661f\u6570\u636e<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>\u670d\u52a1\u548c\u534f\u8bae\u7684\u5173\u7cfb<\/h3>\n<ul>\n<li>\u672c\u5c42\u534f\u8bae\u8981\u9760\u4e0b\u5c42\u63d0\u4f9b\u7684\u670d\u52a1\u6765\u5b9e\u73b0<\/li>\n<li>\u672c\u5c42\u5b9e\u4f53\u901a\u8fc7\u534f\u8bae\u4e3a\u4e0a\u5c42\u63d0\u4f9b\u672c\u5c42\u7684\u670d\u52a1<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241204164522978.png\" alt=\"image-20241204164522978\" style=\"zoom:50%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241204163617682.png\" alt=\"image-20241204163617682\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u6570\u636e\u5355\u5143(DU)<\/h3>\n<p>SDU\u662f\u4e0b\u5c42\u4f20\u8f93\u5230\u672c\u5c42\u7684\u6570\u636e, \u7ecf\u8fc7\u81ea\u5df1\u7684\u5904\u7406\u540e, \u52a0\u5de5\u4e0a\u81ea\u5df1\u7684\u5934(Header), \u4f5c\u4e3aPDU\u7ee7\u7eed\u5411\u4e0a\u4f20\u8f93<\/p>\n<p>\u7b2cn\u5c42\u7684PDU\u662f\u7b2cn-1\u5c42(\u4e0a\u5c42)\u7684SDU<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241204163915007.png\" alt=\"image-20241204163915007\" style=\"zoom:50%;\" \/><\/p>\n<p>\u5b9e\u9645\u4e0a, \u672c\u5c42\u62ff\u5230SDU\u7684\u5904\u7406\u4f1a\u5f88\u590d\u6742, \u4f1a\u5207\u5206, \u4e22\u5f03, \u5c01\u88c5,   \u590d\u6742\u5904\u7406\u7b49\u7b49<\/p>\n<h3>\u5bf9\u590d\u6742\u7cfb\u7edf\u4f7f\u7528\u5206\u5c42\u7684\u597d\u5904<\/h3>\n<ul>\n<li>\u6982\u5ff5\u5316: \u7ed3\u6784\u6e05\u6670, \u4fbf\u4e8e\u6807\u8bc6\u7ec4\u4ef6\u548c\u63cf\u8ff0\u5173\u7cfb<\/li>\n<li>\u7ed3\u6784\u5316: \u6a21\u5757\u5f7c\u6b64\u72ec\u7acb, \u6613\u4e8e\u7ef4\u62a4\u548c\u5347\u7ea7<\/li>\n<\/ul>\n<h3>TCP\/IP\u534f\u8bae\u6808<\/h3>\n<ul>\n<li><strong>\u5e94\u7528\u5c42<\/strong>: \u7f51\u7edc\u5e94\u7528(\u57fa\u672c\u5355\u4f4d\u662f\u62a5\u6587, message)\n<ul>\n<li>\u4e3a\u4eba\u7c7b\u7528\u6237\u6216\u8005\u5176\u4ed6\u8fdb\u7a0b\u63d0\u4f9b\u7f51\u7edc\u5e94\u7528\u670d\u52a1<\/li>\n<li>FTP, SMTP, HTTP, DNS<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u4f20\u8f93\u5c42<\/strong>: \u4e3b\u673a\u4e4b\u95f4\u7684\u6570\u636e\u4f20\u8f93(\u57fa\u672c\u5355\u4f4d\u662f\u6bb5, segment)\n<ul>\n<li>\u5728\u7f51\u7edc\u5c42\u63d0\u4f9b\u7684\u7aef\u5230\u7aef\u57fa\u7840\u4e0a, \u5c06\u4e0d\u53ef\u9760\u901a\u4fe1\u53d8\u4e3a\u53ef\u9760\u901a\u4fe1<\/li>\n<li>\u533a\u5206\u8fdb\u7a0b<\/li>\n<li>TCP, UDP<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u7f51\u7edc\u5c42<\/strong>: \u4e3a\u6570\u636e\u62a5\u4ece\u6e90\u5230\u76ee\u7684\u9009\u62e9\u8def\u7531(\u57fa\u672c\u5355\u4f4d\u662f\u5206\u7ec4, packet)\n<ul>\n<li>\u4e3b\u673a\u4e4b\u95f4\u7aef\u5230\u7aef\u7684\u901a\u4fe1, \u4e0d\u53ef\u9760<\/li>\n<li>IP, \u8def\u7531\u9009\u62e9\u534f\u8bae<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u94fe\u8def\u5c42<\/strong>: \u76f8\u90bb\u8282\u70b9\u4e4b\u95f4\u7684\u6570\u636e\u4f20\u8f93(\u57fa\u672c\u5355\u4f4d\u662f\u5e27, frame)\n<ul>\n<li>\u4e24\u4e2a\u76f8\u90bb\u8282\u70b9\u7684\u901a\u4fe1, \u70b9\u5230\u70b9<\/li>\n<li>\u53ef\u9760\u6216\u8005\u4e0d\u53ef\u9760<\/li>\n<li>PPP, 802.11(wifi), Ethernet<\/li>\n<li>\u7f51\u5361, \u8df3(hop)<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u7269\u7406\u5c42<\/strong>: \u5728\u7269\u7406\u94fe\u8def\u4e0a(\u57fa\u672c\u5355\u4f4d\u662fbit)\n<ul>\n<li>\u62ff\u5230\u94fe\u8def\u5c42\u7ed9\u51fa\u7684\u5e27(frame), \u8f6c\u5316\u4e3a\u7269\u7406\u4fe1\u53f7(\u7535\u78c1\u6ce2, \u5149, &#8230;)<\/li>\n<li>\u4e5f\u5728\u7f51\u5361\u4e0a<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/2288178-20221105214116583-921255460.png\" alt=\"img\" style=\"zoom:50%;\" \/><\/p>\n<h3>ISO\/OSI \u53c2\u8003\u6a21\u578b<\/h3>\n<ul>\n<li><strong>\u8868\u793a\u5c42<\/strong>: \u4e92\u8054\u7f51\u5e94\u7528\u89e3\u91ca\u4f20\u8f93\u7684\u6570\u636e, \u8fd9\u6837\u4ee5\u6765, \u5e94\u7528\u5c42\u5c31\u53ea\u5173\u5fc3\u8bed\u4e49\u65b9\u9762\u7684\u4fe1\u606f, \u800c\u65e0\u9700\u5173\u5fc3\u6570\u636e\u5f62\u5f0f<\/li>\n<li><strong>\u4f1a\u8bdd\u5c42<\/strong>: \u7ef4\u6301\u4f1a\u8bdd(session), \u6570\u636e\u4ea4\u6362\u540c\u6b65, \u68c0\u67e5\u70b9, \u6062\u590d<\/li>\n<\/ul>\n<p>\u5728TCP\/IP\u534f\u8bae\u6808\u4e2d, \u7f3a\u5c11\u4e0a\u9762\u7684\u4e24\u5c42\u2014\u2014\u8fd9\u4e0d\u4ee3\u8868TCP\/IP\u6ca1\u6709\u76f8\u5173\u529f\u80fd, \u800c\u662f\u5c06\u4ed6\u4eec\u5408\u5e76\u5230\u4e86\u5e94\u7528\u5c42\u4e2d, \u8ba9\u7f51\u7edc\u5e94\u7528\u7a0b\u5e8f\u81ea\u5df1\u5b8c\u6210\u4f1a\u8bdd\u7ba1\u7406\u548c\u6570\u636e\u89e3\u91ca<\/p>\n<h2>1.8 \u5386\u53f2<\/h2>\n<h3>\u65e9\u671f(1960\u5e74\u4ee5\u524d): \u7ebf\u8def\u4ea4\u6362\u7f51\u7edc<\/h3>\n<p>\u7ebf\u8def\u4ea4\u6362\u7f51\u7edc\u7684\u79cd\u79cd\u7279\u6027\u4f7f\u5176\u4e0d\u9002\u5408\u8ba1\u7b97\u673a\u4e4b\u95f4\u7684\u901a\u4fe1<\/p>\n<ul>\n<li>\u7ebf\u8def\u5efa\u7acb\u65f6\u95f4\u8fc7\u957f<\/li>\n<li>\u72ec\u4eab\u65b9\u5f0f\u5360\u7528, \u4e0d\u9002\u5408\u9635\u53d1\u7684\u573a\u5408<\/li>\n<li>\u53ef\u9760\u6027\u4e0d\u9ad8: \u6838\u5fc3\u8282\u70b9\u635f\u6bc1\u5bfc\u81f4\u762b\u75ea<\/li>\n<li>\u6709\u4e09\u4e2a\u7ec4\u72ec\u7acb\u5f00\u5c55\u5206\u7ec4\u4ea4\u6362\u7684\u7814\u7a76<\/li>\n<\/ul>\n<h3>1962-1972: \u65e9\u671f\u7684\u5206\u7ec4\u4ea4\u6362\u6982\u5ff5<\/h3>\n<ul>\n<li>ARPA-Net: \u5c0f\u578b\u7684\u5206\u7ec4\u4ea4\u6362\u5b9e\u9a8c\u7f51\u7edc<\/li>\n<li>\u6700\u5f00\u59cb\u7ed9\u519b\u65b9\u7528, \u540e\u9762\u8f6c\u6c11\u7528<\/li>\n<li>\u4f7f\u7528NCP\u534f\u8bae: \u76f8\u5f53\u4e8eTCP+IP<\/li>\n<li>\u6bcf\u53f0\u8bbe\u5907\u5373\u662f\u4e3b\u673a\u8bbe\u5907, \u4e5f\u662f\u4ea4\u6362\u8bbe\u5907<\/li>\n<\/ul>\n<h3>1972-1980: \u5404\u79cd\u4e13\u7528\u7f51\u7edc<\/h3>\n<ul>\n<li>ARPA-Net\u8bc1\u660e\u4e86\u5206\u7ec4\u4ea4\u6362\u53ef\u884c\u6027<\/li>\n<li>\u5404\u79cd\u5b58\u50a8\u8f6c\u53d1\u7684\u7f51\u7edc\u5174\u8d77<\/li>\n<li>\u534f\u8bae\u6df7\u4e71, IBM\u5185\u90e8\u5c31\u670940\u591a\u79cd<\/li>\n<\/ul>\n<p>Cerf &amp; Kahn \u7f51\u7edc\u4e92\u8054\u539f\u5219(\u4e92\u8054\u7f51\u4e4b\u7236)<\/p>\n<ul>\n<li>\u6781\u7b80, \u81ea\u6cbb<\/li>\n<li>\u5c3d\u529b\u800c\u4e3a\u670d\u52a1\u6a21\u578b<\/li>\n<li>\u65e0\u72b6\u6001\u8def\u7531\u5668: \u4e0d\u7ef4\u62a4\u901a\u8baf\u72b6\u6001<\/li>\n<li>\u5206\u5e03\u63a7\u5236<\/li>\n<li>\u6781\u5177\u5305\u5bb9\u6027<\/li>\n<\/ul>\n<h3>1980-1990: \u4f53\u7cfb\u7ed3\u6784\u53d8\u5316, \u7f51\u7edc\u6570\u91cf\u6fc0\u589e, \u5e94\u7528\u4e30\u5bcc<\/h3>\n<ul>\n<li>1983\u5e74\u5b95\u673aARPA-Net, \u5347\u7ea7\u4e86TCP\/IP\u534f\u8bae(Flag-Day)<\/li>\n<li>\u51fa\u73b0SMTP, FTP, TCP\u62e5\u585e\u63a7\u5236\u7b49\u65b0\u7684\u534f\u8bae<\/li>\n<li>DNS\u51fa\u73b0<\/li>\n<li>\u51fa\u73b0\u4e86\u5176\u4ed6\u7684, \u56fd\u5bb6\u7ea7\u7684\u5206\u7ec4\u4ea4\u6362\u7f51\u7edc<\/li>\n<\/ul>\n<h3>1990-2000: \u5546\u4e1a\u5316, Web<\/h3>\n<ul>\n<li>NSF\u5bf9ARPA-Net\u7684\u8bbf\u95ee\u8bbe\u5907\u95f4\u5efa\u7acb\u4e86NSF-Net, \u5f62\u6210\u53cc\u9aa8\u5e72\u7f51\u7edc<\/li>\n<li>NSF-Net\u653e\u5bbd\u4e86\u5546\u4e1a\u5e94\u7528<\/li>\n<li>Unix\u5728\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u514d\u8d39\u6346\u7ed1\u4e86TCP\/IP\u652f\u6301<\/li>\n<\/ul>\n<h3>2000- : \u6301\u7eed\u6269\u5f20, \u5f02\u5e38\u590d\u6742<\/h3>\n<ul>\n<li>TCP\/IP\u5177\u6709\u5305\u5bb9\u6027, \u751f\u547d\u529b\u5f88\u5f3a<\/li>\n<li>\u65b0\u4e00\u4ee3\u6740\u624b\u7ea7\u5e94\u7528\u4fc3\u8fdb\u4e86\u4e92\u8054\u7f51\u8fdb\u4e00\u6b65\u53d1\u5c55<\/li>\n<li>ISP\u4e0d\u65ad\u6269\u5f20<\/li>\n<li>\u5b89\u5168\u6027\u95ee\u9898, \u62e5\u585e\u95ee\u9898\u4e0d\u65ad\u51fa\u73b0\u548c\u88ab\u4fee\u8ba2<\/li>\n<li>\u7f51\u7edc\u53d8\u5f97\u5f02\u5e38\u590d\u6742<\/li>\n<\/ul>\n<hr \/>\n<h1>Chap2. \u5e94\u7528\u5c42<\/h1>\n<h2>2.1 \u5e94\u7528\u5c42\u534f\u8bae\u539f\u7406<\/h2>\n<p>\u7f51\u7edc\u5e94\u7528\u6570\u4e0d\u80dc\u6570: Email, Web, \u8fdc\u7a0b\u767b\u5f55, P2P\u6587\u4ef6\u5171\u4eab, \u5373\u65f6\u901a\u4fe1\u8f6f\u4ef6, \u7f51\u7edc\u6e38\u620f, \u6d41\u5a92\u4f53, \u89c6\u9891\u4f1a\u8bae, \u793e\u4ea4\u7f51\u7edc, \u641c\u7d22\u5f15\u64ce, &#8230;<\/p>\n<p>\u5e94\u7528\u5c42\u662f\u4e92\u8054\u7f51\u4e2d\u534f\u8bae\u6700\u591a\u7684\u5c42, \u5982\u679c\u613f\u610f, \u53ef\u4ee5\u81ea\u5df1\u7f16\u5199\u7a0b\u5e8f\u89c4\u5b9a\u534f\u8bae<\/p>\n<p>\u7f51\u7edc\u6838\u5fc3\u4e2d\u6ca1\u6709\u5e94\u7528\u5c42\u8f6f\u4ef6, \u5e94\u7528\u5c42\u53ea\u5728\u7aef\u7cfb\u7edf\u4e0a<\/p>\n<h3>\u5ba2\u6237-\u670d\u52a1\u5668(C\/S)\u4f53\u7cfb\u7ed3\u6784<\/h3>\n<ul>\n<li>\u670d\u52a1\u5668\u4e00\u76f4\u8fd0\u884c, \u5b88\u5019\u5728\u56fa\u5b9aIP\u7684\u56fa\u5b9a\u7aef\u53e3\u4e0a<\/li>\n<li>\u670d\u52a1\u5668\u662f\u4e2d\u5fc3, \u5b58\u50a8\u8d44\u6e90<\/li>\n<li>\u5ba2\u6237\u7aef\u4e3b\u52a8\u8bf7\u6c42\u670d\u52a1\u5668<\/li>\n<\/ul>\n<p>\u7f3a\u70b9:<\/p>\n<p>C\/S\u4f53\u7cfb\u7684\u53ef\u6269\u5c55\u6027\u8f83\u5dee, \u670d\u52a1\u5668\u786c\u4ef6, \u7f51\u7edc\u786c\u4ef6\u6269\u5bb9\u56f0\u96be<\/p>\n<p>\u5f53\u9700\u6c42\u8d85\u8fc7\u627f\u8f7d\u529b\u65f6, \u6027\u80fd\u4f1a\u65ad\u5d16\u5f0f\u4e0b\u964d<\/p>\n<h3>\u5bf9\u7b49\u4f53(P2P)\u4f53\u7cfb\u7ed3\u6784<\/h3>\n<ul>\n<li>(\u51e0\u4e4e)\u6ca1\u6709\u4e00\u76f4\u8fd0\u884c\u7684\u670d\u52a1\u5668<\/li>\n<li>\u4efb\u610f\u7aef\u7cfb\u7edf\u4e4b\u95f4\u53ef\u4ee5\u901a\u4fe1<\/li>\n<li>\u6bcf\u4e00\u4e2a\u8282\u70b9\u5373\u662f\u5ba2\u6237\u7aef\u53c8\u662f\u670d\u52a1\u5668\n<ul>\n<li>\u81ea\u6269\u5c55\u6027: \u65b0\u7684\u8282\u70b9\u52a0\u5165, \u540c\u65f6\u5e26\u6765\u4e86\u8bf7\u6c42\u548c\u670d\u52a1\u80fd\u529b<\/li>\n<\/ul>\n<\/li>\n<li>\u53c2\u4e0e\u7684\u4e3b\u673a\u95f4\u6b47\u6027\u8fde\u63a5, IP\u5730\u5740\u53ef\u53d8<\/li>\n<\/ul>\n<p>\u7f3a\u70b9: \u96be\u4ee5\u7ba1\u7406<\/p>\n<h3>\u6df7\u5408\u4f53\u7cfb\u7ed3\u6784<\/h3>\n<p>Napster: <\/p>\n<p>\u96c6\u4e2d\u5f0f\u6587\u4ef6\u641c\u7d22, P2P\u6587\u4ef6\u4f20\u8f93, \u7528\u6237\u8d8a\u591a\u6027\u80fd\u5c31\u8d8a\u5f3a<\/p>\n<p>\u5373\u65f6\u901a\u4fe1\u8f6f\u4ef6: <\/p>\n<p>\u96c6\u4e2d\u5f0f\u7ba1\u7406\u7528\u6237\u4fe1\u606f(\u6ce8\u518c, \u5728\u7ebf\u72b6\u6001), P2P\u7528\u6237\u79c1\u804a<\/p>\n<h3>\u8fdb\u7a0b\u901a\u4fe1<\/h3>\n<p>\u8fdb\u7a0b\u662f\u4e3b\u673a\u4e0a\u8fd0\u884c\u7684\u5e94\u7528\u7a0b\u5e8f<\/p>\n<ul>\n<li>\u540c\u4e00\u4e2a\u4e3b\u673a\u5185, \u91c7\u7528\u8fdb\u7a0b\u95f4\u901a\u4fe1\u673a\u5236\u901a\u4fe1(\u64cd\u4f5c\u7cfb\u7edf\u5b9a\u4e49)<\/li>\n<li>\u4e0d\u540c\u4e3b\u673a, \u91c7\u7528\u4ea4\u6362\u62a5\u6587(Message)\u6765\u901a\u4fe1<\/li>\n<li><strong>\u5ba2\u6237\u7aef\u8fdb\u7a0b<\/strong>\u53d1\u8d77\u901a\u4fe1<\/li>\n<li><strong>\u670d\u52a1\u5668\u8fdb\u7a0b<\/strong>\u7b49\u5f85\u8fde\u63a5<\/li>\n<\/ul>\n<p>\u5373\u4f7f\u662fP2P\u67b6\u6784, \u5728\u6bcf\u4e2a\u4f1a\u8bdd(session)\u4e0a\u4e5f\u6709\u5ba2\u6237\u7aef\u8fdb\u7a0b\u548c\u670d\u52a1\u5668\u8fdb\u7a0b\u7684\u533a\u522b<\/p>\n<h3>\u5206\u5e03\u5f0f\u8fdb\u7a0b\u9700\u8981\u89e3\u51b3\u7684\u95ee\u9898<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241211203913947.png\" alt=\"image-20241211203913947\" style=\"zoom:66%;\" \/><\/p>\n<p><strong>\u95ee\u98981: <\/strong>\u8fdb\u7a0b\u6807\u8bc6\u4e0e\u5bfb\u5740<\/p>\n<ul>\n<li>\u4e0d\u4ec5\u8981\u6709\u552f\u4e00\u7684\u6807\u8bc6, \u8fd8\u8981\u63d0\u4f9b\u627e\u5230\u5730\u5740\u7684\u65b9\u6cd5<\/li>\n<li>\u8fdb\u7a0b\u7684\u6807\u8bc6: IP+Port, \u4e00\u4e9b\u77e5\u540d\u7aef\u53e3\u662f\u7ea6\u5b9a\u7684\u8fdb\u7a0b<\/li>\n<\/ul>\n<p><strong>\u95ee\u98982: <\/strong>\u4f20\u8f93\u5c42\u5982\u4f55\u7ed9\u5e94\u7528\u5c42\u63d0\u4f9b\u670d\u52a1<\/p>\n<p>\u4f4d\u7f6e: SAP\u2014\u2014TCP\/IP: socket<\/p>\n<ul>\n<li>\u4f20\u8f93\u5c42\u7684SAP\u662f\u7aef\u53e3\u53f7, \u6bd4\u5982HTTPS\u5728443, SSH\u572822<\/li>\n<\/ul>\n<p>\u5f62\u5f0f: API\u2014\u2014TCP\/IP: socketAPI<\/p>\n<p>\u5e94\u7528\u5c42\u8981\u7a7f\u8fc7\u5c42\u95f4\u63a5\u53e3\u8fbe\u5230\u4f20\u8f93\u5c42, \u9700\u8981\u643a\u5e26\u4fe1\u606f:<\/p>\n<ul>\n<li>\u8981\u4f20\u8f93\u7684\u62a5\u6587(\u672c\u5c42\u7684SDU)<\/li>\n<li>\u6570\u636e\u6e90: \u6211\u65b9\u8fdb\u7a0b\u7684IP+Port (TCP\/UDP)<\/li>\n<li>\u6570\u636e\u76ee\u6807: \u5bf9\u65b9\u8fdb\u7a0bIP+Port (TCP\/UDP)<\/li>\n<\/ul>\n<p>IP+Port\u88ab\u79f0\u4f5c\u7aef\u8282\u70b9(End Point)<\/p>\n<p>\u4f20\u8f93\u5c42\u7684\u5b9e\u4f53\u4f1a\u6839\u636e\u4e0a\u9762\u7684\u4fe1\u606f\u5c01\u88c5\u4e3aTCP\u62a5\u6587\u6bb5\u6216\u8005UDP\u6570\u636e\u62a5. \u79fb\u4ea4\u4e0b\u5c42\u65f6, \u5c01\u88c5\u4e3aIP\u6570\u636e\u62a5: \u53ea\u66b4\u9732\u6e90IP, \u76ee\u6807IP<\/p>\n<p>\u65b0\u7684\u95ee\u9898: \u4e0a\u9762\u7684\u4fe1\u606f\u592a\u591a\u4e86, socketAPI\u6bcf\u6b21\u4f20\u8f93\u5982\u679c\u90fd\u643a\u5e26\u5c31\u592a\u8fc7\u4e8e\u7e41\u7410<\/p>\n<p>\u5f15\u5165\u4e00\u4e2a\u4ee3\u53f7\u7528\u6765\u7ba1\u7406\u901a\u4fe1\u7684\u5355\u65b9\u6216\u8005\u53cc\u65b9: socket: integer, \u8fd9\u6837\u53ef\u4ee5\u8ba9\u7a7f\u8fc7\u5c42\u95f4\u63a5\u53e3\u7684\u4fe1\u606f\u91cf\u6700\u5c0f<\/p>\n<ul>\n<li>\u7c7b\u6bd4\u4e3aos\u6253\u5f00\u6587\u4ef6\u7684\u53e5\u67c4: \u5bf9\u53e5\u67c4\u7684\u64cd\u4f5c\u5c31\u662f\u5bf9\u6587\u4ef6\u7684\u64cd\u4f5c<\/li>\n<li>socket\u662f\u672c\u5730\u4fbf\u4e8e\u7ba1\u7406\u5f15\u5165\u7684, \u5bf9\u65b9\u4e0d\u77e5\u9053<\/li>\n<li>\u66f4\u8fdb\u4e00\u6b65\u7684, \u672c\u5730\u53ea\u6709\u5e94\u7528\u5c42, \u7f51\u7edc\u5c42\u77e5\u9053socket(socket\u662f\u4ed6\u4eec\u4e8c\u8005\u7684\u7ea6\u5b9a)<\/li>\n<\/ul>\n<p>TCP-socket\u662f\u56db\u5143\u7ec4: \u6e90IP, \u6e90\u7aef\u53e3, \u76ee\u6807IP, \u76ee\u6807\u7aef\u53e3<\/p>\n<p>OS\u4f1a\u7ef4\u62a4\u4e00\u5f20socket\u8868, socket-[\u56db\u5143\u7ec4]-\u72b6\u6001, socket\u7684\u5728TCP\u5efa\u7acb\u65f6\u5206\u9636\u6bb5\u5efa\u7acb, \u540e\u9762\u4f1a\u8bb2<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241211214737233.png\" alt=\"image-20241211214737233\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241211215458059.png\" alt=\"image-20241211215458059\" style=\"zoom:40%;\" \/><\/p>\n<p>UDP-socket\u4e0d\u9700\u8981\u63e1\u624b, \u53ea\u5305\u542b\u672c\u5730IP, \u672c\u5730\u7aef\u53e3, \u5728\u4f20\u8f93\u62a5\u6587\u7684\u65f6\u5019, \u7ed9\u51fa\u5bf9\u65b9IP, \u5bf9\u65b9\u7aef\u53e3 <\/p>\n<p><strong>\u95ee\u98983: <\/strong>\u5982\u4f55\u4f7f\u7528\u4f20\u8f93\u5c42\u63d0\u4f9b\u7684\u670d\u52a1 <\/p>\n<p>\u5b9a\u4e49\u5e94\u7528\u5c42\u534f\u8bae: \u62a5\u6587\u683c\u5f0f, \u89e3\u91ca, \u65f6\u5e8f\u7b49<\/p>\n<p>\u7f16\u5236\u7a0b\u5e8f, \u901a\u8fc7API\u8c03\u7528\u7f51\u7edc\u57fa\u7840\u8bbe\u65bd\u63d0\u4f9b\u7684\u901a\u4fe1\u670d\u52a1\u6765\u4f20\u8f93\u62a5\u6587, \u89e3\u6790\u62a5\u6587, \u5b9e\u73b0\u5e94\u7528\u65f6\u5e8f\u7b49<\/p>\n<p>\u5e94\u7528\u5c42\u534f\u8bae\u5b9a\u4e49\u4e86\u8fd0\u884c\u5728\u4e0d\u540c\u7aef\u7cfb\u7edf\u4e0a\u7684\u8fdb\u7a0b\u5982\u4f55\u4ea4\u6362\u62a5\u6587<\/p>\n<ul>\n<li>\u62a5\u6587\u7c7b\u578b: \u76f8\u5e94\/\u4f20\u8f93<\/li>\n<li>\u62a5\u6587\u683c\u5f0f\u4e0e\u8bed\u6cd5\u8bed\u4e49<\/li>\n<li>\u62a5\u6587\u52a8\u4f5c\u548c\u6b21\u5e8f<\/li>\n<\/ul>\n<p>\u5e94\u7528\u534f\u8bae\u4ec5\u4ec5\u662f\u5e94\u7528\u548c\u7f51\u7edc\u76f8\u5173\u7684\u4e00\u90e8\u5206, \u5e94\u7528\u8fd8\u6709\u7528\u6237\u754c\u9762, \u4e1a\u52a1\u903b\u8f91\u7b49\u7b49<\/p>\n<h3>\u5b89\u5168\u6027<\/h3>\n<p>TCP\u548cUDP\u90fd\u4e0d\u63d0\u4f9b\u5b89\u5168\u6027\u4fdd\u969c<\/p>\n<p>SSL: \u5728TCP\u4e0a\u5c42\u5b9e\u73b0, \u63d0\u4f9b\u52a0\u5bc6\u7684TCP\u94fe\u63a5<\/p>\n<h2>2.2 Web and HTTP<\/h2>\n<h3>\u57fa\u672c\u6982\u5ff5<\/h3>\n<ul>\n<li>Web\u9875\u9762\u672c\u8eab\u662f\u5bf9\u8c61, \u4e5f\u7531\u5bf9\u8c61\u7ec4\u6210<\/li>\n<li>\u5bf9\u8c61\u53ef\u4ee5\u662fHTML\u6587\u4ef6, JPEG\u56fe\u50cf, Java\u7a0b\u5e8f, MP3\u97f3\u9891\u7b49\u7b49<\/li>\n<li>Web\u9875\u7528\u8fc7URL\u5f15\u7528\u5bf9\u8c61<\/li>\n<\/ul>\n<p>URL\u683c\u5f0f:<\/p>\n<pre><code>protocol:\/\/user:pswd@www.jlu.edu.cn\/someDept\/pic.jpeg:port<\/code><\/pre>\n<p>\u4efb\u4f55\u5bf9\u8c61\u90fd\u53ef\u4ee5\u901a\u8fc7URL\u8fdb\u884c\u552f\u4e00\u6807\u8bc6<\/p>\n<h3>HTTP\u6982\u51b5<\/h3>\n<p>HTTP: \u8d85\u6587\u672c\u4f20\u8f93\u534f\u8bae, Web\u7684\u5e94\u7528\u5c42\u534f\u8bae, \u57fa\u4e8eTCP<\/p>\n<ul>\n<li>C\/S\u6a21\u5f0f, \u5ba2\u6237\u8bf7\u6c42, \u670d\u52a1\u5668\u54cd\u5e94<\/li>\n<\/ul>\n<p>\u4f7f\u7528TCP\u7684\u8fc7\u7a0b<\/p>\n<ul>\n<li>\u5ba2\u6237\u53d1\u8d77\u4e00\u4e2a\u4e0e\u670d\u52a1\u5668\u7684TCP\u8fde\u63a5(\u5efa\u7acb\u5957\u63a5\u5b57), \u7aef\u53e3\u53f7\u4e3a80<\/li>\n<li>\u670d\u52a1\u5668\u63a5\u53d7\u5ba2\u6237\u7684TCP\u8fde\u63a5\u8bf7\u6c42<\/li>\n<li>\u5728\u6d4f\u89c8\u5668(HTTP\u5ba2\u6237\u7aef)\u4e0eWeb\u670d\u52a1\u5668(HTTP\u670d\u52a1\u5668)\u4ea4\u6362HTTP\u62a5\u6587(\u5e94\u7528\u5c42\u534f\u8bae\u62a5\u6587)<\/li>\n<li>\u5b8c\u6210\u4ea4\u6362\u540eTCP\u8fde\u63a5\u5173\u95ed<\/li>\n<\/ul>\n<p>HTTP\u662f\u65e0\u72b6\u6001\u7684, \u670d\u52a1\u5668\u4e0d\u7ef4\u62a4\u5173\u4e8e\u5ba2\u6237\u7684\u4fe1\u606f<\/p>\n<blockquote>\n<p>\u7ef4\u62a4\u72b6\u6001\u7684\u534f\u8bae\u5f88\u590d\u6742, \u9700\u8981\u7ef4\u62a4\u5386\u53f2\u4fe1\u606f, \u5904\u7406\u4e0d\u4e00\u81f4, \u65e0\u72b6\u6001\u7684\u670d\u52a1\u5668\u53ef\u4ee5\u652f\u6301\u66f4\u591a\u7684\u5ba2\u6237\u7aef<\/p>\n<\/blockquote>\n<ul>\n<li>\n<p>\u9996\u5148, \u670d\u52a1\u5668\u4f1a\u5efa\u7acb\u4e00\u4e2awaiting socket\u76d1\u542c80\u7aef\u53e3, \u8fd9\u4e2asocket\u4e0d\u4f20\u8f93\u5b9e\u9645\u6570\u636e, \u53ea\u7b49\u5f85\u7528\u6237\u8fde\u63a5<\/p>\n<\/li>\n<li>\n<p>\u7136\u540e, \u5ba2\u6237\u673a\u8bf7\u6c42\u8fde\u63a5, \u88abwaiting socket\u76d1\u542c\u5230, \u6b64\u65f6\u8fdb\u884c\u4e09\u6b21\u63e1\u624b\u6d41\u7a0b, \u6d41\u7a0b\u7ed3\u675f\u540e, \u8fde\u63a5\u6b63\u5f0f\u5efa\u7acb<\/p>\n<\/li>\n<li>\n<p>waiting socket\u5185\u90e8\u6709\u4e00\u4e2a\u961f\u5217(backlog), \u5b58\u50a8\u6b63\u5f0f\u5efa\u7acb\u8fde\u63a5, \u4f46\u6ca1\u6709\u5904\u7406\u7684\u8bf7\u6c42<\/p>\n<\/li>\n<li>\n<p>\u670d\u52a1\u5668\u4ece\u961f\u5217\u4e2d\u53d6\u51fa\u8fde\u63a5\u8bf7\u6c42, \u4e3a\u5176\u521b\u5efa\u4e00\u4e2a\u65b0\u7684connect socket, \u8fd9\u4e2asocket\u7528\u4e8e\u6b63\u5f0f\u7684\u901a\u4fe1<\/p>\n<\/li>\n<li>\n<p>waiting socket\u7ee7\u7eed\u6301\u7eed\u76d1\u542c<\/p>\n<\/li>\n<\/ul>\n<h3>\u975e\u6301\u4e45HTTP(HTTP\/1.0)<\/h3>\n<ul>\n<li>\u6700\u591a\u4e00\u4e2a\u5bf9\u8c61\u5728TCP\u94fe\u63a5\u4e0a\u53d1\u9001<\/li>\n<li>\u4e0b\u8f7d\u591a\u4e2a\u5bf9\u8c61\u9700\u5efa\u7acb\u591a\u4e2aTCP\u94fe\u63a5<\/li>\n<\/ul>\n<p>\u8fc7\u7a0b\u5b9e\u4f8b<\/p>\n<ol>\n<li>\n<p>HTTP\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668<code>www.jlu.edu.cn<\/code>\u768480\u7aef\u53e3\u53d1\u9001HTTP\u8bf7\u6c42<\/p>\n<\/li>\n<li>\n<p>\u4f4d\u4e8e<code>www.jlu.edu.cn<\/code>\u7684HTTP\u670d\u52a1\u5668\u6b63\u5728\u76d1\u542c80\u7aef\u53e3\u7684HTTP\u8bf7\u6c42, \u4ed6\u6536\u5230\u8bf7\u6c42, \u63a5\u53d7\u5e76\u901a\u77e5\u5ba2\u6237\u7aef<\/p>\n<\/li>\n<li>\n<p>HTTP\u5ba2\u6237\u7aef\u5411TCP\u8fde\u63a5\u7684\u5957\u63a5\u5b57\u53d1\u9001HTTP\u8bf7\u6c42\u62a5\u6587, \u6807\u8bc6\u9700\u6c42\u5bf9\u8c61<code>\/index.html<\/code><\/p>\n<\/li>\n<li>\n<p>HTTP\u670d\u52a1\u5668\u63a5\u6536\u5230\u8bf7\u6c42\u62a5\u6587, \u68c0\u7d22\u88ab\u8bf7\u6c42\u7684\u5bf9\u8c61, \u5e76\u5c06\u4e4b\u5c01\u88c5\u5728\u4e00\u4e2a\u54cd\u5e94\u62a5\u6587\u91cc, \u901a\u8fc7\u5957\u63a5\u5b57\u53d1\u9001\u56de\u5ba2\u6237\u7aef<\/p>\n<\/li>\n<li>\n<p>\u5ba2\u6237\u7aef\u6536\u5230\u4e86<code>index.html<\/code>\u5bf9\u8c61, \u89e3\u6790\u8fc7\u7a0b\u4e2d\u53d1\u73b0\u5f15\u7528\u4e86<code>1.jpg<\/code>\u56fe\u50cf\u5bf9\u8c61<\/p>\n<\/li>\n<li>\n<p>\u8bf7\u6c42<code>1.jpg<\/code>\u5bf9\u8c61, \u91cd\u590d\u6b65\u9aa41-5<\/p>\n<\/li>\n<\/ol>\n<blockquote>\n<p>\u4e00\u4e9b\u6587\u4ef6\u4f20\u8f93\u8f6f\u4ef6\u4e5f\u8dd1\u5728HTTP\u534f\u8bae\u4e0a<\/p>\n<\/blockquote>\n<h3>\u6301\u4e45HTTP(HTTP\/1.1 \u9ed8\u8ba4)<\/h3>\n<ul>\n<li>\u591a\u4e2a\u5bf9\u8c61\u53ef\u4ee5\u540c\u65f6\u5728\u4e00\u4e2a\u94fe\u63a5\u4e0a\u53d1\u9001<\/li>\n<\/ul>\n<p>\u6301\u4e45HTTP\u5206\u4e3a\u4e24\u79cd\u7c7b\u578b<\/p>\n<ul>\n<li>\u6d41\u6c34\u7ebf\u65b9\u5f0f(HTTP\/1.1\u9ed8\u8ba4): \u8fde\u7eed\u53d1\u8bf7\u6c42, \u8fde\u7eed\u83b7\u53d6<\/li>\n<li>\u975e\u6d41\u6c34\u7ebf\u65b9\u5f0f: \u8bf7\u6c42\u4e00\u4e2a, \u83b7\u53d6\u4e00\u4e2a, \u518d\u8bf7\u6c42\u4e00\u4e2a<\/li>\n<\/ul>\n<h3>\u54cd\u5e94\u65f6\u95f4\u6a21\u578b<\/h3>\n<p>\u5f80\u8fd4\u65f6\u95f4(RTT): \u4e00\u4e2a\u5c0f\u7684\u5206\u7ec4\u4ece\u5ba2\u6237\u7aef\u5230\u670d\u52a1\u5668, \u518d\u56de\u5230\u5ba2\u6237\u7aef\u5230\u65f6\u95f4(\u4f20\u8f93\u65f6\u95f4\u5ffd\u7565)<\/p>\n<p>\u54cd\u5e94\u65f6\u95f4<\/p>\n<ul>\n<li>\u4e00\u4e2aRTT\u7528\u6765\u53d1\u8d77TCP\u8fde\u63a5<\/li>\n<li>\u4e00\u4e2aRTT\u7528\u6765HTTP\u8bf7\u6c42\u5e76\u7b49\u5f85HTTP\u54cd\u5e94<\/li>\n<li>\u6587\u4ef6\u4f20\u8f93\u65f6\u95f4<\/li>\n<\/ul>\n<p>\u603b\u51712xRTT+\u4f20\u8f93\u65f6\u95f4<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213114451126.png\" alt=\"image-20241213114451126\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>\u975e\u6301\u4e45HTTP\u6bcf\u4e2a\u5bf9\u8c61\u90fd\u8981\u7ecf\u5386\u4e0a\u9762\u7684\u8fc7\u7a0b<\/li>\n<li>\u6301\u4e45HTTP\u53ea\u6709\u9996\u4e2a\u5bf9\u8c61\u7ecf\u5386<\/li>\n<\/ul>\n<h3>\u8bf7\u6c42\u62a5\u6587<\/h3>\n<p>HTTP\u62a5\u6587\u4e24\u79cd\u7c7b\u578b: \u8bf7\u6c42\/\u54cd\u5e94, ASCII\u7f16\u7801\u53ef\u8bfb<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213115812783.png\" alt=\"image-20241213115812783\" style=\"zoom:33%;\" \/><\/p>\n<p>\u547d\u4ee4\u5b57<\/p>\n<ul>\n<li>GET: \u8bf7\u6c42\u6587\u4ef6, HEAD\u548cBODY\u90fd\u8981<\/li>\n<li>POST: \u4e0a\u4f20\u6587\u4ef6<\/li>\n<li>HEAD: \u83b7\u53d6\u5934(\u7528\u6765\u7ef4\u62a4, \u5efa\u7d22\u5f15\u7b49)<\/li>\n<\/ul>\n<p>\u8bf7\u6c42\u62a5\u6587\u7684\u901a\u7528\u683c\u5f0f<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213120104656.png\" alt=\"image-20241213120104656\" style=\"zoom:50%;\" \/><\/p>\n<p>\u5982\u679c\u662fGET, \u5219BODY\u4e00\u822c\u662f\u7a7a\u7684<\/p>\n<p>\u5982\u679c\u662fPOST, \u5219\u9700\u8981\u7ed9\u51faBOD Y, \u4ee3\u8868\u4e0a\u4f20\u4ec0\u4e48<\/p>\n<h3>\u5411\u670d\u52a1\u5668\u63d0\u4ea4\u8868\u5355<\/h3>\n<ul>\n<li>\n<p>POST\u65b9\u5f0f: Entity Body\u7ed9\u51fa\u5185\u5bb9<\/p>\n<\/li>\n<li>\n<p>GET\u65b9\u5f0f: \u7528\u8fc7\u8f93\u5165\u8bf7\u6c42\u884c\u7684URL\u53c2\u6570\u63d0\u4ea4<\/p>\n<\/li>\n<\/ul>\n<h3>HTTP\u5e38\u7528\u547d\u4ee4<\/h3>\n<p>HTTP\/1.0<\/p>\n<ul>\n<li>GET<\/li>\n<li>POST<\/li>\n<li>HEAD<\/li>\n<\/ul>\n<p>HTTP\/1.1 \u6dfb\u52a0<\/p>\n<ul>\n<li>PUT: \u63d0\u4ea4\u5bf9\u8c61, \u5e76\u4e0a\u8f7d\u5230URL\u5b57\u6bb5\u7684\u6307\u5b9a\u8def\u5f84<\/li>\n<li>DELETE: \u5220\u9664URL\u5b57\u6bb5\u6307\u5b9a\u7684\u6587\u4ef6<\/li>\n<\/ul>\n<h3>HTTP\u54cd\u5e94\u62a5\u6587<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213134741559.png\" alt=\"image-20241213134741559\" style=\"zoom:50%;\" \/><\/p>\n<p>Content-Length\u662f\u5f88\u6709\u5fc5\u8981\u7684, \u4ed6\u5e2e\u52a9\u5e94\u7528\u7a0b\u5e8f\u533a\u5206\u62a5\u6587\u7684\u754c\u9650. <\/p>\n<p>\u8fd9\u662f\u56e0\u4e3aTCP\u63d0\u4f9b\u7684\u662f\u5b57\u8282\u6d41(Byte Stream), \u4e0d\u7ef4\u62a4\u6570\u636e\u8fb9\u754c. \u6570\u636e\u53ef\u80fd\u88ab\u62c6\u6210\u591a\u4efd, \u4e5f\u53ef\u80fd\u4f1a\u88ab\u5408\u5e76. TCP\u53ea\u4fdd\u8bc1\u4f20\u8f93\u987a\u5e8f\u6b63\u786e<\/p>\n<p>\u670d\u52a1\u5668\u5148\u540e\u53d1\u9001\u4e86<code>Hello<\/code> \u548c<code>World<\/code>, \u5ba2\u6237\u7aef\u53ef\u80fd\u6536\u5230<\/p>\n<ul>\n<li><code>HelloWorld<\/code><\/li>\n<li><code>HelloW<\/code>, <code>orld<\/code><\/li>\n<li><code>H<\/code>, <code>el<\/code>, <code>lloWor<\/code>, <code>d<\/code><\/li>\n<\/ul>\n<p>\u66f4\u8fdb\u4e00\u6b65\u7684, \u5047\u8bbe\u670d\u52a1\u5668\u53d1\u9001HTTP\u54cd\u5e94\u62a5\u6587<\/p>\n<pre><code>HTTP\/1.1 200 OK\nContent-Length: 13\n\nHello, World!<\/code><\/pre>\n<pre><code>HTTP\/1.1 200 OK\nContent-Length: 12\n\nHello again!<\/code><\/pre>\n<p>\u7531\u4e8eTCP\u6570\u636e\u6d41\u7684\u7279\u6027, \u5ba2\u6237\u7aef\u6536\u5230\u7684\u53ef\u80fd\u662f<\/p>\n<pre><code>HTTP\/1.1 200 OK\nContent-Length: 13\n\nHello, Worl<\/code><\/pre>\n<pre><code>d!HTTP\/1.1 200 OK\nContent-Length: 12\n\nHello agai<\/code><\/pre>\n<pre><code>n!<\/code><\/pre>\n<p>\u6b64\u65f6\u5c31\u9700\u8981\u5e94\u7528\u9700\u8981\u81ea\u884c\u901a\u8fc7content-length\u6765\u89e3\u6790\u5185\u5bb9<\/p>\n<blockquote>\n<p>\u56e0\u4e3a TCP \u672c\u8eab\u4e0d\u63d0\u4f9b\u62a5\u6587\u8fb9\u754c\u7684\u6982\u5ff5, \u5e94\u7528\u5c42\u534f\u8bae(\u5982 HTTP)\u9700\u8981\u81ea\u5df1\u8bbe\u8ba1\u673a\u5236\u6765\u544a\u8bc9\u5bf9\u65b9&quot;\u6d88\u606f\u4ece\u54ea\u91cc\u5f00\u59cb, \u5230\u54ea\u91cc\u7ed3\u675f&quot;<\/p>\n<\/blockquote>\n<p>\u524d\u9762\u63d0\u5230\u7684HTTP\u8bf7\u6c42\u62a5\u6587\u4e2d, content-length\u4e0d\u662f\u5fc5\u987b\u8981\u7684. <\/p>\n<ul>\n<li>\n<p>\u5982\u679c\u662fPOST\u8bf7\u6c42, \u643a\u5e26\u5b9e\u4f53, \u5219\u9700\u8981<\/p>\n<\/li>\n<li>\n<p>\u5982\u679c\u662fGET\u8bf7\u6c42, \u5219\u4e0d\u9700\u8981. \u8fd9\u662f\u56e0\u4e3a\u8bf7\u6c42\u6709\u660e\u786e\u7684\u7ed3\u675f\u6807\u5fd7<code>\\r\\n<\/code>, \u5c31\u7b97\u88ab\u622a\u65ad\u4e86, \u4e5f\u53ef\u4ee5\u533a\u5206\u8fb9\u754c<\/p>\n<\/li>\n<\/ul>\n<h3>HTTP\u54cd\u5e94\u72b6\u6001\u7801<\/h3>\n<ul>\n<li><strong>200 OK<\/strong>: \u8bf7\u6c42\u6210\u529f, \u5bf9\u8c61\u4f1a\u5728\u54cd\u5e94\u62a5\u6587\u540e\u7eed\u7ed9\u51fa<\/li>\n<li><strong>301 Moved Permanently<\/strong>: \u8bf7\u6c42\u5bf9\u8c61\u88ab\u6c38\u4e45\u8f6c\u79fb, \u65b0\u7684URL\u5728\u54cd\u5e94\u62a5\u6587\u7684Location\u9996\u90e8\u884c\u6307\u5b9a, \u6b64\u65f6\u5ba2\u6237\u7aef\u8f6f\u4ef6\u4f1a\u81ea\u52a8\u7528\u65b0\u7684URL\u83b7\u53d6\u5bf9\u8c61<\/li>\n<li><strong>400 Bad Request<\/strong>: \u8bf7\u6c42\u4e0d\u80fd\u88ab\u670d\u52a1\u5668\u89e3\u8bfb<\/li>\n<li><strong>404 Not Found<\/strong>: \u8bf7\u6c42\u7684\u6587\u6863\u5728\u670d\u52a1\u5668\u627e\u4e0d\u5230<\/li>\n<li><strong>505 HTTP Version Not Supported<\/strong><\/li>\n<\/ul>\n<h3>\u7528\u6237-\u670d\u52a1\u5668\u72b6\u6001: cookies<\/h3>\n<p>HTTP\u534f\u8bae\u662f\u65e0\u72b6\u6001\u7684, \u4f46\u662f\u5728\u5b9e\u9645\u5e94\u7528\u4e2d, \u7ecf\u5e38\u4f1a\u6709\u5173\u4e8e\u72b6\u6001\u7684\u5b9e\u9645\u9700\u6c42<\/p>\n<ul>\n<li>\u5ba2\u6237\u7aef\u5728\u9996\u6b21\u8bbf\u95ee\u670d\u52a1\u5668\u65f6, \u670d\u52a1\u5668\u53d1\u73b0\u4e86\u9996\u6b21\u8bf7\u6c42, \u4e3a\u4ed6\u751f\u6210\u4e86cookie, \u5e76\u5728\u54cd\u5e94\u62a5\u6587\u4e2d\u8fd4\u56de\u4e86<\/li>\n<li>\u5ba2\u6237\u7aef\u5b58\u50a8\u4e86\u8fd9\u4e2acookie, \u6b64\u65f6cookie\u4e00\u5f0f\u4e24\u4efd, \u5206\u522b\u7ef4\u62a4\u5728\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u4e2d\n<ul>\n<li>\u670d\u52a1\u5668\u53ef\u80fd\u4f1a\u5efa\u7acbcookie-\u6570\u636e\u5e93\u7684\u7d22\u5f15, \u7ef4\u62a4\u4e30\u5bcc\u4fe1\u606f<\/li>\n<li>\u5ba2\u6237\u7aef\u672c\u5730\u4e5f\u4f1a\u5b58\u50a8\u81ea\u5df1\u7684\u4fe1\u606f<\/li>\n<\/ul>\n<\/li>\n<li>\u5728\u4ee5\u540e(\u6570\u5929\u6570\u4e2a\u6708)\u7684\u901a\u8baf\u4e2d, cookie\u90fd\u4f1a\u5939\u5728\u5ba2\u6237\u7aef\u8bf7\u6c42\u4e2d, \u4f5c\u4e3a\u7528\u6237\u6807\u8bc6. \u670d\u52a1\u5668\u53ef\u4ee5\u901a\u8fc7cookie\u7ef4\u62a4\u7528\u6237\u72b6\u6001, \u6bd4\u5982\u767b\u9646\u72b6\u6001, \u6bd4\u5982\u8d2d\u7269\u8f66\u7b49\u7b49<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213143214271.png\" alt=\"image-20241213143214271\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>cookie\u5728\u5e26\u6765\u4fbf\u5229\u7684\u540c\u65f6, \u4e5f\u5e26\u6765\u591a\u79cd\u9690\u79c1\u95ee\u9898. \u957f\u671f\u643a\u5e26cookie\u4fbf\u4e8e\u7b2c\u4e09\u65b9\u5206\u6790\u7528\u6237\u884c\u4e3a<\/p>\n<\/blockquote>\n<h3>Web\u7f13\u5b58(\u4ee3\u7406\u670d\u52a1\u5668)<\/h3>\n<p>\u4e0d\u8bbf\u95ee\u539f\u59cb\u670d\u52a1\u5668, \u5373\u53ef\u6ee1\u8db3\u5ba2\u6237\u8bf7\u6c42<\/p>\n<p>\u5982\u679c\u7f13\u5b58\u547d\u4e2d, \u76f4\u63a5\u8fd4\u56de, \u5426\u5219\u8bf7\u6c42\u539f\u670d\u52a1\u5668<\/p>\n<p>\u7f13\u5b58\u5373\u662f\u5ba2\u670d\u7aef, \u4e5f\u662f\u670d\u52a1\u5668, \u901a\u5e38\u7531ISP\u5b89\u88c5<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213143717188.png\" alt=\"image-20241213143717188\" style=\"zoom:50%;\" \/><\/p>\n<ul>\n<li>\u4f18\u5316\u54cd\u5e94\u901f\u5ea6<\/li>\n<li>\u51cf\u5c11\u670d\u52a1\u5668\u5185\u7f51\u4e0a\u884c\u6d41\u91cf<\/li>\n<li>\u8ba9\u8f83\u5f31\u7684ICP\u4e5f\u80fd\u591f\u6709\u6548\u63d0\u4f9b\u5185\u5bb9<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213144344677.png\" alt=\"image-20241213144344677\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u6761\u4ef6GET<\/h3>\n<p>\u7f13\u5b58\u53ef\u80fd\u5e26\u6765\u65b0\u7684\u95ee\u9898: \u7f13\u5b58\u7684\u6587\u4ef6\u7248\u672c\u80af\u80fd\u4f1a\u843d\u540e\u4e8e\u670d\u52a1\u5668\u7684<\/p>\n<p>\u5f15\u5165\u6761\u4ef6GET: <code>If-Modified-Since<\/code> \u7528\u6765\u5411\u670d\u52a1\u5668\u67e5\u8be2\u6587\u4ef6\u5728\u67d0\u4e2a\u65f6\u95f4\u70b9\u540e\u662f\u5426\u88ab\u4fee\u6539\u4e86<\/p>\n<ul>\n<li>\u5982\u679c\u4fee\u6539\u4e86, \u56de\u590d200 OK, \u5e76\u643a\u5e26\u65b0\u5bf9\u8c61<\/li>\n<li>\u5982\u679c\u6ca1\u6709, \u53ea\u56de\u590d\u4e00\u4e2aHEAD, 304 Not Modified<\/li>\n<\/ul>\n<h2>2.3 FTP<\/h2>\n<p>FTP\u5373\u662f\u5e94\u7528\u5c42\u7684\u534f\u8bae, \u4e5f\u662f\u4e00\u79cd\u5177\u4f53\u7684\u5e94\u7528<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213185422365.png\" alt=\"image-20241213185422365\" style=\"zoom:40%;\" \/><\/p>\n<ul>\n<li>FTP\u670d\u52a1\u5668\u76d1\u542c21\u7aef\u53e3, \u8fd0\u884c\u5728TCP\u4e0a<\/li>\n<li>RFC 959<\/li>\n<li>C\/S\u6a21\u5f0f<\/li>\n<li>\u7528\u6237\u53ef\u4ee5\u5411\u670d\u52a1\u5668\u4e0a\u4f20\u6587\u4ef6, \u4e5f\u53ef\u4ee5\u4e0b\u8f7d\u670d\u52a1\u5668\u4e0a\u7684\u6587\u4ef6<\/li>\n<\/ul>\n<h3>FTP\u7684\u5de5\u4f5c\u5b9e\u4f8b<\/h3>\n<ol>\n<li>FTP\u5ba2\u6237\u7aef\u5411FTP\u670d\u52a1\u5668\u768421\u7aef\u53e3\u53d1\u9001\u8fde\u63a5\u8bf7\u6c42, \u4f7f\u7528TCP\u4f5c\u4e3a\u4f20\u8f93\u534f\u8bae, \u5efa\u7acb<strong>\u63a7\u5236\u8fde\u63a5<\/strong><\/li>\n<li>\u670d\u52a1\u5668\u9a8c\u8bc1\u5ba2\u6237\u8eab\u4efd\u4fe1\u606f, \u8fd4\u56de\u786e\u8ba4<\/li>\n<li>\u5ba2\u6237\u7aef\u901a\u8fc7\u63a7\u5236\u8fde\u63a5\u53d1\u9001\u547d\u4ee4\u6d4f\u89c8\u76ee\u5f55, \u5e76\u8bf7\u6c42\u4f20\u8f93\u6587\u4ef6<\/li>\n<li>\u670d\u52a1\u5668\u63a5\u5230\u8bf7\u6c42\u540e\n<ul>\n<li><strong>\u4e3b\u52a8\u6a21\u5f0f<\/strong>: \u5ba2\u6237\u7aef\u901a\u8fc7\u63a7\u5236\u53d1\u9001<code>PORT<\/code>\u547d\u4ee4, \u5305\u542b\u81ea\u5df1\u7684IP\u548c\u7aef\u53e3\u7aef\u53e3, \u8981\u6c42\u670d\u52a1\u5668\u4ece20\u53f7\u7aef\u53e3\u4e3b\u52a8\u8bf7\u6c42\u8fde\u63a5<\/li>\n<li><strong>\u88ab\u52a8\u6a21\u5f0f<\/strong>: \u5ba2\u6237\u7aef\u53d1\u9001<code>PASV<\/code>\u547d\u4ee4, \u8981\u6c42\u670d\u52a1\u5668\u63d0\u4f9b\u65b0\u7684\u7aef\u53e3, \u5ba2\u6237\u7aef\u6765\u8bf7\u6c42\u8fde\u63a5<\/li>\n<li>\u65b0\u5efa\u7acb\u7684\u8fde\u63a5\u53eb<strong>\u6570\u636e\u8fde\u63a5<\/strong><\/li>\n<\/ul>\n<\/li>\n<li>\u6587\u4ef6\u4f20\u8f93\u5b8c\u6210\u540e, \u6570\u636e\u8fde\u63a5\u5173\u95ed<\/li>\n<\/ol>\n<p>FTP\u662f\u6709\u5929\u7136\u7684\u6709\u72b6\u6001\u534f\u8bae(\u5ba2\u6237\u8eab\u4efd, \u5f53\u524d\u76ee\u5f55\u7b49)<\/p>\n<p>FTP\u5728\u63a7\u5236\u8fde\u63a5\u4e0a, \u4f20\u8f93ASCII\u53ef\u8bfb\u6587\u672c<\/p>\n<p>\u76f8\u5bf9\u4e8e\u6570\u636e(\u5e26\u5185)\u8fde\u63a5\u6765\u8bf4, \u63a7\u5236\u8fde\u63a5\u53c8\u53eb\u5e26\u5916(Out of Band)\u8fde\u63a5<\/p>\n<h2>2.4 Email<\/h2>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213191739006.png\" alt=\"image-20241213191739006\" style=\"zoom:40%;\" \/><\/p>\n<p>\u4e3b\u8981\u7ec4\u6210\u90e8\u5206: \u7528\u6237\u4ee3\u7406, \u90ae\u4ef6\u670d\u52a1\u5668, \u90ae\u4ef6\u4f20\u8f93\u534f\u8bae<\/p>\n<h3>\u7528\u6237\u4ee3\u7406<\/h3>\n<ul>\n<li>\u7528\u6237\u754c\u9762<\/li>\n<li>\u9700\u8981\u914d\u7f6e\u90ae\u4ef6\u670d\u52a1\u5668<\/li>\n<li>\u4ece\u90ae\u4ef6\u670d\u52a1\u5668\u6536\u53d6\u90ae\u4ef6\u6765\u9605\u8bfb<\/li>\n<li>\u64b0\u5199\u90ae\u4ef6\u540e\u4e0a\u4f20\u5230\u90ae\u4ef6\u670d\u52a1\u5668\u7684\u53d1\u9001\u961f\u5217<\/li>\n<li>\u7528\u6237\u4ee3\u7406\u7684\u534f\u8bae\u6709POP3, IMAP, HTTP\u7b49, \u7528\u6765\u62c9\u53d6\u90ae\u4ef6\u5230\u672c\u5730<\/li>\n<\/ul>\n<h3>\u90ae\u4ef6\u670d\u52a1\u5668<\/h3>\n<ul>\n<li>\u7ba1\u7406\u548c\u7ef4\u62a4\u7528\u6237\u7684\u90ae\u4ef6<\/li>\n<li>\u90ae\u4ef6\u53d1\u9001\u961f\u5217<\/li>\n<li>\u670d\u52a1\u5668\u4e4b\u95f4\u4ee5SMTP\u534f\u8bae\u4ea4\u4e92<\/li>\n<\/ul>\n<h3>SMTP [RFC 2821]<\/h3>\n<ul>\n<li>\u76d1\u542c25\u7aef\u53e3, \u4f20\u8f93ASCII\u53ef\u8bfb\u62a5\u6587(\u5305\u62ec\u547d\u4ee4, \u54cd\u5e94, \u90ae\u4ef6\u672c\u8eab\u5185\u5bb9)<\/li>\n<li>\u7528\u6237\u5728\u672c\u5730\u64b0\u5199\u90ae\u4ef6\u540e, \u901a\u8fc7SMTP\u534f\u8bae\u53d1\u9001\u7ed9\u670d\u52a1\u5668\u7684\u53d1\u9001\u961f\u5217<\/li>\n<li>\u670d\u52a1\u5668\u4e4b\u95f4\u7684\u4e2d\u7ee7\u4e5f\u901a\u8fc7SMTP\u53d1\u9001, \u76f4\u5230\u76ee\u6807\u670d\u52a1\u5668<\/li>\n<li>SMTP\u662f\u6301\u4e45\u8fde\u63a5<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213194627728.png\" alt=\"image-20241213194627728\" style=\"zoom:40%;\" \/><\/p>\n<p>\u4e0a\u56fe\u4e2d, 2, 4, \u4e3aSMTP\u8d1f\u8d23\u7684\u8fc7\u7a0b, 6\u4e3aPOP3\/IMAP\/HTTP\u8d1f\u8d23\u7684\u8fc7\u7a0b<\/p>\n<p>\u4e0eHTTP\u76f8\u6bd4, HTTP\u4e00\u4efd\u62a5\u6587\u53ea\u5305\u542b\u4e00\u4e2a\u5bf9\u8c61, \u800cSMTP\u53ef\u4ee5\u5c01\u88c5\u591a\u4e2a<\/p>\n<h3>\u90ae\u4ef6\u62a5\u6587\u683c\u5f0f<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213195937765.png\" alt=\"image-20241213195937765\" style=\"zoom:40%;\" \/><\/p>\n<p>MIME: \u591a\u7528\u9014\u4e92\u8054\u7f51\u90ae\u4ef6\u6269\u5c55, \u5141\u8bb8\u90ae\u4ef6\u5305\u542b\u975e\u6587\u672c\u5185\u5bb9<\/p>\n<h3>\u90ae\u4ef6\u8bbf\u95ee\u534f\u8bae<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241213201730956.png\" alt=\"image-20241213201730956\" style=\"zoom:33%;\" \/><\/p>\n<table>\n<thead>\n<tr>\n<th>\u7279\u6027<\/th>\n<th><strong>POP3<\/strong><\/th>\n<th><strong>IMAP<\/strong><\/th>\n<th><strong>HTTP\uff08Webmail\uff09<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>\u5b58\u50a8\u4f4d\u7f6e<\/strong><\/td>\n<td>\u672c\u5730<\/td>\n<td>\u670d\u52a1\u5668<\/td>\n<td>\u670d\u52a1\u5668<\/td>\n<\/tr>\n<tr>\n<td><strong>\u591a\u8bbe\u5907\u540c\u6b65\u652f\u6301<\/strong><\/td>\n<td>\u4e0d\u652f\u6301<\/td>\n<td>\u652f\u6301<\/td>\n<td>\u652f\u6301<\/td>\n<\/tr>\n<tr>\n<td><strong>\u79bb\u7ebf\u8bbf\u95ee<\/strong><\/td>\n<td>\u652f\u6301<\/td>\n<td>\u90e8\u5206\u652f\u6301\uff08\u7f13\u5b58\uff09<\/td>\n<td>\u4e0d\u652f\u6301<\/td>\n<\/tr>\n<tr>\n<td><strong>\u7f51\u7edc\u4f9d\u8d56<\/strong><\/td>\n<td>\u4f4e<\/td>\n<td>\u4e2d<\/td>\n<td>\u9ad8<\/td>\n<\/tr>\n<tr>\n<td><strong>\u5b89\u5168\u6027<\/strong><\/td>\n<td>\u672c\u5730\u5b58\u50a8\uff0c\u89c6\u52a0\u5bc6\u60c5\u51b5\u800c\u5b9a<\/td>\n<td>\u4f9d\u8d56\u4e8e\u670d\u52a1\u5668\u7684\u52a0\u5bc6\u548c\u914d\u7f6e<\/td>\n<td>HTTPS \u63d0\u4f9b\u9ad8\u5b89\u5168\u6027<\/td>\n<\/tr>\n<tr>\n<td><strong>\u4f7f\u7528\u573a\u666f<\/strong><\/td>\n<td>\u5355\u8bbe\u5907\u7528\u6237\uff0c\u4f4e\u5e26\u5bbd\u73af\u5883<\/td>\n<td>\u591a\u8bbe\u5907\u7528\u6237\uff0c\u4f01\u4e1a\u529e\u516c<\/td>\n<td>\u4e34\u65f6\u8bbf\u95ee\u90ae\u4ef6\uff0c\u8f7b\u91cf\u7ea7\u7528\u6237<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>2.5 DNS<\/h2>\n<p>DNS\u4e0d\u662f\u7ed9\u4eba\u670d\u52a1\u7684\u5e94\u7528, \u800c\u662f\u7ed9\u5176\u4ed6\u5e94\u7528\u670d\u52a1\u7684\u5e94\u7528<\/p>\n<p>DNS\u8d1f\u8d23\u57df\u540d\u5230IP\u5730\u5740\u7684\u8f6c\u6362<\/p>\n<h3>DNS\u7684\u5fc5\u8981\u6027<\/h3>\n<p>\u5728\u7f51\u7edc\u4e0a, \u6240\u6709\u7684\u4e3b\u673a, \u8def\u7531\u5668\u7528IP\u5730\u5740\u6807\u8bc6\u548c\u5bfb\u5740<\/p>\n<ul>\n<li>IP\u5730\u5740\u96be\u4ee5\u8bb0\u5fc6<\/li>\n<li>\u4eba\u7c7b\u503e\u5411\u4e8e\u4f7f\u7528\u6709\u610f\u4e49\u7684\u5b57\u7b26\u4e32\u6807\u8bc6<\/li>\n<li>\u5b58\u5728\u5b57\u7b26\u4e32\u5230IP\u5730\u5740\u8f6c\u6362\u7684\u5fc5\u8981\u6027<\/li>\n<\/ul>\n<h3>DNS\u7cfb\u7edf\u9700\u8981\u89e3\u51b3\u7684\u95ee\u9898<\/h3>\n<ul>\n<li>\u5982\u4f55\u547d\u540d\u8bbe\u5907: \u5b57\u7b26\u4e32\u7684, \u5c42\u6b21\u5316\u7684<\/li>\n<li>\u5982\u4f55\u5b8c\u6210\u8f6c\u6362: \u5206\u5e03\u5f0f\u7684\u6570\u636e\u5e93\u54cd\u5e94\u67e5\u8be2<\/li>\n<li>\u5982\u4f55\u7ef4\u62a4: \u5982\u4f55\u589e\u52a0\/\u5220\u9664\/\u4fee\u6539\u57df<\/li>\n<\/ul>\n<h3>DNS\u7684\u5386\u53f2<\/h3>\n<p>ARPA-Net\u7684\u89e3\u51b3\u65b9\u6848<\/p>\n<ul>\n<li>\u7528\u7b80\u5355\u5b57\u7b26\u4e32\u4f5c\u4e3a\u4e3b\u673a\u540d, <strong>\u5e73\u9762\u5316<\/strong><\/li>\n<li>\u5b58\u5728\u4e00\u4e2a<strong>\u96c6\u4e2d<\/strong>\u7684\u7ef4\u62a4\u7ad9, \u7ef4\u62a4\u4e00\u4e2a\u4e3b\u673a-IP\u7684\u6620\u5c04\u6e05\u5355<\/li>\n<\/ul>\n<p>\u4e0d\u9002\u5408\u4e3b\u673a\u6570\u91cf\u5f88\u5927\u7684\u60c5\u51b5<\/p>\n<h3>DNS\u7684\u4e3b\u8981\u601d\u8def<\/h3>\n<ul>\n<li>\u5206\u5c42\u7684, \u57fa\u4e8e\u57df\u7684\u547d\u540d\u673a\u5236, \u6811\u72b6<\/li>\n<li>\u5206\u5e03\u5f0f\u7684\u6570\u636e\u5e93\u54cd\u5e94\u67e5\u8be2\u8bf7\u6c42, \u5b8c\u6210\u8f6c\u6362<\/li>\n<li>\u8fd0\u884c\u5728UDP\u4e0a, 53\u53f7\u7aef\u53e3<\/li>\n<\/ul>\n<blockquote>\n<p>\u4e00\u4e2a\u6709\u8da3\u7684\u4e8b\u5b9e: DNS\u867d\u7136\u662f\u4e92\u8054\u7f51\u7684\u6838\u5fc3\u529f\u80fd, \u91cd\u4e2d\u4e4b\u91cd, \u4f46\u5374\u5b9e\u73b0\u5728\u5e94\u7528\u5c42\u4e0a, \u4f4d\u4e8e\u7f51\u7edc\u8fb9\u7f18. \u7c7b\u4f3cDNS\u7684\u4f8b\u5b50\u8fd8\u6709\u5f88\u591a<\/p>\n<p>\u8fd9\u8bf4\u660e\u4e92\u8054\u7f51\u7684\u590d\u6742\u6027\u4f53\u73b0\u5728\u8fb9\u7f18, \u800c\u975e\u6838\u5fc3\u4e0a<\/p>\n<\/blockquote>\n<h3>DNS\u7684\u529f\u80fd<\/h3>\n<ul>\n<li>\u6700\u4e3b\u8981\u7684\u529f\u80fd: \u57df\u540d-IP\u8f6c\u6362<\/li>\n<li>\u4e3b\u673a\u522b\u540d-\u89c4\u8303\u540d\u7684\u8f6c\u6362: Host aliasing (CNAME)<\/li>\n<li>\u8d1f\u8f7d\u5747\u8861: Load Distribution (\u540c\u4e00\u4e2a\u57df\u540d\u53ef\u4ee5\u89e3\u6790\u51fa\u4e0d\u540cIP)<\/li>\n<\/ul>\n<h3>DNS\u57df\u540d\u7ed3\u6784<\/h3>\n<p>\u4e00\u4e2a\u5e73\u9762\u7684\u547d\u540d\u4f1a\u6709\u5f88\u591a\u91cd\u540d, DNS\u91c7\u7528\u4e86\u6811\u72b6\u7ed3\u6784<\/p>\n<p>Internet\u6839\u88ab\u5212\u5206\u4e3a\u51e0\u767e\u4e2a\u9876\u7ea7\u57df\u540d:<\/p>\n<ul>\n<li>\u901a\u7528\u7684: .com, .edu, .gov, .org, &#8230;<\/li>\n<li>\u56fd\u5bb6\u7684: .cn, .us, .jp, &#8230;<\/li>\n<\/ul>\n<p>\u6bcf\u4e2a(\u5b50)\u57df\u4e0b\u53ef\u4ee5\u5206\u4e3a\u82e5\u5e72\u5b50\u57df, \u6811\u53f6\u662f\u4e3b\u673a<\/p>\n<p>DNS\u6839\u540d\u5b57\u670d\u52a1\u5668\u603b\u5171\u670913\u4e2a<\/p>\n<p>\u57df\u540d\u7528<code>.<\/code>\u95f4\u9694\u4e0d\u540c\u7ea7\u522b, \u4ece\u6839\u5f80\u6811\u53f6, \u6bcf\u4e2a\u5c42\u6b21\u9694\u5f00, \u6bcf\u4e2a\u57df\u7684\u5212\u5206\u65b9\u5f0f\u4e0d\u540c<\/p>\n<pre><code>csw.jlu.edu.cn<\/code><\/pre>\n<p>cn\u662f\u9876\u7ea7\u57df\u540d, edu\u662f\u4e8c\u7ea7, &#8230;<\/p>\n<p>\u57df\u7684\u5212\u5206\u662f\u903b\u8f91\u7684\u7684, \u548c\u7269\u7406\u7f51\u7edc\u6ca1\u6709\u5173\u7cfb. \u540c\u4e00\u4e2a\u57df\u7684\u4e3b\u673a\u53ef\u4ee5\u5728\u4e0d\u540c\u7f51\u7edc\u4e0a:<\/p>\n<p><code>a.jlu.edu.cn<\/code>, <code>b.jlu.edu.cn<\/code>\u53ef\u4ee5\u89e3\u6790\u5230\u4e0d\u540c\u4f4d\u7f6e<\/p>\n<h3>\u540d\u5b57\u670d\u52a1\u5668(Name Server)<\/h3>\n<p>\u96c6\u4e2d\u5f0f\u7684\u670d\u52a1\u5668\u6ca1\u6709\u5bb9\u9519, \u6211\u4eec\u9700\u8981\u5206\u5e03\u5f0f\u7684\u89e3\u51b3\u95ee\u9898<\/p>\n<p>\u5c06\u540d\u5b57\u7a7a\u95f4\u5212\u5206\u4e3a\u4e00\u4e2a\u4e2a\u7684<strong>\u533a\u57df(zone)<\/strong>, \u533a\u57df\u7684\u5212\u5206\u7531\u7ba1\u7406\u8005\u81ea\u5df1\u51b3\u5b9a<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241216172655902.png\" alt=\"image-20241216172655902\" style=\"zoom:40%;\" \/><\/p>\n<p>\u6bcf\u4e2a\u533a\u57df\u6709\u4e00\u4e2a\u6743\u5a01\u540d\u5b57\u670d\u52a1\u5668, \u7ef4\u62a4\u7ba1\u8f96\u8303\u56f4\u5185\u7684\u6743\u5a01\u4fe1\u606f(\u57df\u540d\u5230IP\u7684\u6620\u5c04). \u540d\u5b57\u670d\u52a1\u5668\u53ef\u4ee5\u5728\u533a\u57df\u4e4b\u5916<\/p>\n<p>\u4e0a\u7ea7\u7ef4\u62a4\u7740\u4e0b\u7ea7\u7684\u6307\u9488, \u7528\u4ee5\u7ee7\u7eed\u89e3\u6790<\/p>\n<h3>TLD\u670d\u52a1\u5668<\/h3>\n<p>\u9876\u7ea7\u57df\u540d\u670d\u52a1\u5668, \u8d1f\u8d23\u901a\u7528  \u9876\u7ea7\u57df\u540d(org, net, edu, &#8230;)\u548c\u6240\u6709\u56fd\u5bb6\u7ea7\u57df\u540d(cn, uk, us, &#8230;)\u7684\u89e3\u6790<\/p>\n<ul>\n<li>Network solutions\u516c\u53f8\u7ef4\u62a4com TLD\u670d\u52a1\u5668<\/li>\n<li>Educause\u516c\u53f8\u7ef4\u62a4edu TLD\u670d\u52a1\u5668<\/li>\n<\/ul>\n<h3>\u540d\u5b57\u670d\u52a1\u5668\u7ef4\u62a4\u7684\u8d44\u6e90\u8bb0\u5f55<\/h3>\n<p>\u8d44\u6e90\u8bb0\u5f55(resource records)\u5b58\u50a8\u57df\u540d-IP(\u5176\u4ed6)\u6620\u5c04\u5173\u7cfb, \u4e0e\u5b50\u57df\u670d\u52a1\u5668\u7684\u4f4d\u7f6e\u7b49<\/p>\n<p>\u5b58\u50a8\u5728\u540d\u5b57\u670d\u52a1\u5668\u7684\u5206\u5e03\u5f0f\u6570\u636e\u5e93\u4e2d<\/p>\n<p>\u683c\u5f0f(\u5b57\u6bb5): (domain_name, TTL, type, class, vlaue)<\/p>\n<ul>\n<li>\u57df\u540d\u672c\u8eab<\/li>\n<li>TTL: time to live, \u751f\u5b58\u65f6\u95f4, \u6743\u5a01\u8bb0\u5f55\u7684TTL\u662f\u65e0\u7a77\u5927, \u5176\u4ed6\u8bb0\u5f55TTL\u8017\u5c3d\u540e, \u4f1a\u8bf7\u6c42\u6743\u5a01\u540d\u5b57\u670d\u52a1\u5668\u66f4\u65b0<\/li>\n<li>class: \u7c7b\u522b, \u4e92\u8054\u7f51\u4e3aIN<\/li>\n<li>type:\n<ul>\n<li>A: value=ipv4<\/li>\n<li>CNAME: value=\u57df\u540d<\/li>\n<li>MX: alue=\u90ae\u4ef6\u670d\u52a1\u5668\u522b\u540d(\u6b63\u89c4\u540d)<\/li>\n<li>NS: value=\u6743\u5a01\u670d\u52a1\u5668\u57df\u540d<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u67d0\u4e2a\u540d\u5b57\u670d\u52a1\u5668\u7684\u5206\u5e03\u5f0f\u6570\u636e\u5e93\u7684\u8868\u53ef\u80fd\u5982\u4e0b<\/p>\n<table>\n<thead>\n<tr>\n<th>domain_name<\/th>\n<th>TTL<\/th>\n<th>type<\/th>\n<th>class<\/th>\n<th>value<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>csw.jlu.edu.cn<\/td>\n<td>3600<\/td>\n<td>A<\/td>\n<td>IN<\/td>\n<td>202.119.32.1<\/td>\n<\/tr>\n<tr>\n<td><a href=\"http:\/\/www.csw.jlu.edu.cn\">www.csw.jlu.edu.cn<\/a><\/td>\n<td>3600<\/td>\n<td>CNAME<\/td>\n<td>IN<\/td>\n<td>csw.jlu.edu.cn<\/td>\n<\/tr>\n<tr>\n<td>csw.jlu.edu.cn<\/td>\n<td>86400<\/td>\n<td>MX<\/td>\n<td>IN<\/td>\n<td>10 mail.csw.jlu.edu.cn<\/td>\n<\/tr>\n<tr>\n<td>csw.jlu.edu.cn<\/td>\n<td>86400<\/td>\n<td>NS<\/td>\n<td>IN<\/td>\n<td>ns1.jlu.edu.cn<\/td>\n<\/tr>\n<tr>\n<td>csw.jlu.edu.cn<\/td>\n<td>86400<\/td>\n<td>NS<\/td>\n<td>IN<\/td>\n<td>ns2.jlu.edu.cn<\/td>\n<\/tr>\n<tr>\n<td>mails.csw.jlu.edu.cn<\/td>\n<td>3600<\/td>\n<td>A<\/td>\n<td>IN<\/td>\n<td>202.119.32.2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>DNS\u5de5\u4f5c\u8fc7\u7a0b<\/h3>\n<ol>\n<li>\u672c\u5730\u5e94\u7528\u8c03\u7528\u672c\u5730\u89e3\u6790\u5668(resolver)<\/li>\n<li>\u672c\u5730\u89e3\u6790\u5668\u4f5c\u4e3a\u5ba2\u6237\u7aef, \u5411\u672c\u5730DNS\u540d\u5b57\u670d\u52a1\u5668\u53d1\u9001UDP\u7684\u67e5\u8be2\u62a5\u6587(\u672c\u5730DNS\u670d\u52a1\u5668\u7684\u5730\u5740\u624b\u52a8\u914d\/DHCP, \u4e00\u822c\u5728\u7f51\u7edc\u5185)<\/li>\n<li>\u540d\u5b57\u670d\u52a1\u5668\u8fd4\u56de\u54cd\u5e94\u62a5\u6587<\/li>\n<\/ol>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241216175614441.png\" alt=\"image-20241216175614441\" style=\"zoom:50%;\" \/><\/p>\n<h3>\u672c\u5730\u540d\u5b57\u670d\u52a1\u5668<\/h3>\n<p>\u5e76\u4e0d\u4e25\u683c\u5c5e\u4e8e\u5c42\u6b21\u7ed3\u6784, \u6bcf\u4e2aISP(\u5c0f\u533a, \u5927\u5b66)\u90fd\u53ef\u4ee5\u6709\u81ea\u5df1\u7684<\/p>\n<p>\u7f13\u5b58\u4e86\u5f88\u591a\u4fe1\u606f, \u5982\u679c\u547d\u4e2d\u5c31\u8fd4\u56de, \u5982\u679c\u6ca1\u6709\u547d\u4e2d, \u5219\u4ece\u5168\u7403\u7684\u6839\u670d\u52a1\u5668\u5f00\u59cb, \u4f9d\u6b21\u5411\u4e0a\u67e5\u8be2<\/p>\n<ol>\n<li>\u67e5\u8be2\u4efb\u610f\u4e00\u4e2a(13\u4e2a\u4e4b\u4e00)\u6839\u670d\u52a1\u5668, \u5f97\u5230<code>.cn<\/code>\u7684\u6743\u5a01\u540d\u5b57\u670d\u52a1\u5668\u5730\u5740<\/li>\n<li>\u67e5\u8be2<code>.cn<\/code>\u7684\u6743\u5a01\u540d\u5b57\u670d\u52a1\u5668\u5730\u5740, \u5f97\u5230<code>edu.cn<\/code>\u7684\u6743\u5a01\u540d\u5b57\u670d\u52a1\u5668\u5730\u5740<\/li>\n<li>&#8230;<\/li>\n<li>\u67e5\u8be2<code>jlu.edu.cn<\/code>\u7684\u6743\u5a01\u540d\u5b57\u670d\u52a1\u5668, \u5f97\u5230<code>csw.jlu.edu.cn<\/code>\u7684\u786e\u5207IP\u5730\u5740<\/li>\n<\/ol>\n<p>\u5f53\u7136, \u5982\u679c\u7f13\u5b58\u4e86<code>edu.cn<\/code>\u7684\u540d\u5b57\u670d\u52a1\u5668\u5730\u5740, \u5219\u53ef\u4ee5\u76f4\u63a5\u4ece\u8fd9\u4e00\u6b65\u5f00\u59cb\u67e5\u8be2<\/p>\n<h3>\u80f6\u6c34\u8bb0\u5f55(Glue Record)<\/h3>\n<p>\u5f62\u4f3c<code>ns1.jlu.edu.cn<\/code>\u8fd9\u6837\u7684DNS\u670d\u52a1\u4f1a\u5b58\u50a8<code>*.jlu.edu.cn<\/code>, <code>jlu.edu.cn<\/code>\u8fd9\u4e9b\u57df\u540d\u7684\u6743\u5a01\u8bb0\u5f55<\/p>\n<p>\u4e3a\u4e86\u9632\u6b62\u9012\u5f52\u67e5\u8be2, \u5b9e\u9645\u4e0a, <code>ns1.jlu.edu.cn<\/code>\u7684\u6743\u5a01\u8bb0\u5f55\u5728<code>edu.cn<\/code>\u5bf9\u5e94\u7684DNS\u670d\u52a1\u5668\u91cc, \u8fd9\u53eb\u505a\u80f6\u6c34\u8bb0\u5f55(Glue Record)<\/p>\n<h3>DNS\u534f\u8bae\u4e0e\u62a5\u6587<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241216194701607.png\" alt=\"image-20241216194701607\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u7ef4\u62a4: \u65b0\u589e\u4e00\u4e2a\u57df<\/h3>\n<p>\u5047\u8bbe\u73b0\u5728\u8981\u6ce8\u518c\u57df\u540d<code>sssn.tech<\/code>, \u9700\u8981\u7ecf\u8fc7\u5982\u4e0b\u6b65\u9aa4<\/p>\n<p>\u5728\u8d1f\u8d23<code>.tech<\/code>\u7684\u9876\u7ea7\u57df\u540d\u670d\u52a1\u5668\u4e2d\u65b0\u589e<strong>\u4e24\u6761\u8bb0\u5f55<\/strong>, \u4e00\u6761\u662f<code>sssn.tech<\/code>\u7684\u6743\u5a01\u670d\u52a1\u5668\u5730\u5740(NS\u8bb0\u5f55), \u4e00\u6761\u662f<code>sssn.tech<\/code> \u5b50\u57df\u540d\u7684\u670d\u52a1\u5668\u5730\u5740<\/p>\n<p>\u5373, <code>tech TLD<\/code>\u670d\u52a1\u5668\u4e2d\u65b0\u589e\u4e24\u6761\u8bb0\u5f55<\/p>\n<pre><code>sssn.tech, dns1.sssn.tech, NS\ndns1.sssn.tech, 1.1.1.1, A<\/code><\/pre>\n<h2>2.6 P2P\u5e94\u7528<\/h2>\n<h3>\u7eafP2P\u67b6\u6784<\/h3>\n<ul>\n<li>\u6ca1\u6709(\u6216\u6781\u5c11)\u4e00\u76f4\u5728\u8fd0\u884c\u7684\u670d\u52a1\u5668<\/li>\n<li>\u4efb\u610f\u7aef\u7cfb\u7edf\u90fd\u53ef\u4ee5\u76f4\u63a5\u901a\u4fe1<\/li>\n<li>\u5229\u7528peer\u7684\u670d\u52a1\u80fd\u529b<\/li>\n<li>Peer\u8282\u70b9\u95f4\u6b47\u4e0a\u7f51, \u6bcf\u6b21IP \u5730\u5740\u90fd\u6709\u53ef\u80fd\u53d8\u5316<\/li>\n<li>\u5206\u6563\u4e86\u6d41\u91cf\u538b\u529b<\/li>\n<\/ul>\n<p>\u4f8b\u5b50: \u6587\u4ef6\u5206\u53d1(BitTorrent), \u6d41\u5a92\u4f53(KanKan), VoIP(Skype)<\/p>\n<h3>\u6587\u4ef6\u5206\u53d1: C\/S vs P2P<\/h3>\n<p>\u5728C\/S\u6a21\u5f0f\u4e2d, \u4ece\u4e00\u4e2a\u670d\u52a1\u5668\u5206\u53d1\u6587\u4ef6, \u5927\u5c0f\u4e3aF, \u5230N\u4e2apeer\u9700\u8981\u591a\u957f\u65f6\u95f4? \u77ed\u677f\u6548\u5e94: <\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241216203637106.png\" alt=\"image-20241216203637106\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728P2P\u6a21\u5f0f\u4e2d<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241216210316224.png\" alt=\"image-20241216210316224\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241216210341299.png\" alt=\"image-20241216210341299\" style=\"zoom:33%;\" \/><\/p>\n<p>P2P\u6a21\u5f0f\u662f\u52a8\u6001\u7684, \u53ef\u7ba1\u7406\u6027\u8f83\u5dee<\/p>\n<h3>P2P\u7684\u7ba1\u7406\u65b9\u5f0f: \u7ed3\u6784\u5316\/\u975e\u7ed3\u6784\u5316<\/h3>\n<p>P2P\u7684\u7ba1\u7406\u65b9\u5f0f\u53ef\u4ee5\u5206\u4e3a\u975e\u7ed3\u6784\u5316\u7684\u548c\u7ed3\u6784\u5316\u7684\u4e24\u79cd<\/p>\n<p>\u7ed3\u6784\u5316P2P\u53c8\u88ab\u79f0\u4f5c\u57fa\u4e8e\u5206\u5e03\u5f0f\u6563\u5217\u8868(DHT)\u7684P2P<\/p>\n<p>peer\u8282\u70b9\u5728\u5e94\u7528\u5c42\u4e4b\u95f4\u4e92\u76f8\u7684<strong>\u903b\u8f91\u8fde\u63a5<\/strong>\u5f62\u6210\u4e86\u8986\u76d6\u7f51(overlay), \u5982\u679c\u8986\u76d6\u7f51\u662f\u4efb\u610f\u7684, \u6ca1\u6709\u7b97\u6cd5\u7ec4\u7ec7\u7684, \u5219\u662f\u975e\u7ed3\u6784\u5316, \u53cd\u4e4b\u5219\u4e3a\u56fa\u5b9a\u7684, \u7ed3\u6784\u5316\u7684\u8986\u76d6\u7f51<\/p>\n<h3>\u975e\u7ed3\u6784\u5316P2P: \u96c6\u4e2d\u5f0f\u76ee\u5f55<\/h3>\n<p>Napster\u662f\u5178\u578b\u7684\u4f8b\u5b50: \u6709\u4e00\u4e2a\u4e2d\u5fc3\u7684\u76ee\u5f55\u670d\u52a1\u5668, \u7ef4\u62a4\u5404\u4e2a\u8282\u70b9\u7684\u8d44\u6e90\u4fe1\u606f. \u5f53\u4e00\u4f4d\u5ba2\u6237\u9700\u8981\u8d44\u6e90\u65f6, \u67e5\u8be2\u670d\u52a1\u5668\u83b7\u5f97\u6709\u8d44\u6e90\u7684peer\u540d\u5355, \u7136\u540e\u518d\u8bf7\u6c42peer<\/p>\n<p>\u5f53Alice\u4ece\u5bf9\u7b49\u65b9Bob\u4e0b\u8f7d\u6587\u4ef6F\u65f6, \u670d\u52a1\u5668\u4e5f\u7ef4\u62a4\u4e86Alice\u7684\u4fe1\u606f, \u5219\u5176\u4ed6\u7528\u6237\u4e5f\u53ef\u4ee5\u540c\u65f6\u4eceAlice\u5904\u4e0b\u8f7dF<\/p>\n<p>\u6bcf\u4e2a\u8282\u70b9\u4e0a\u7ebf\u65f6, \u90fd\u9700\u8981\u5411\u76ee\u5f55\u670d\u52a1\u5668\u62a5\u544a\u81ea\u8eabIP\u4e0e\u672c\u5730\u7684\u8d44\u6e90, \u670d\u52a1\u5668\u7ef4\u62a4\u4e86\u5f53\u524d\u6d3b\u8dc3\u7684\u7528\u6237\u5217\u8868. \u4e0b\u7ebf\u65f6, \u4e5f\u9700\u8981\u6c47\u62a5<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241217131703617.png\" alt=\"image-20241217131703617\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5b58\u5728\u7684\u95ee\u9898: \u5355\u70b9\u6545\u969c(\u76ee\u5f55\u670d\u52a1\u5668), \u6027\u80fd\u74f6\u9888, \u7248\u6743\u4fb5\u72af<\/p>\n<h3>\u975e\u7ed3\u6784\u5316P2P: \u5b8c\u5168\u5206\u5e03\u5f0f<\/h3>\n<p>Gnutella\u662f\u5f88\u597d\u7684\u4f8b\u5b50, \u6ca1\u6709\u4e2d\u5fc3\u5316\u670d\u52a1\u5668, \u6240\u6709\u8282\u70b9\u90fd\u662fpeer. \u4ee3\u7801\u5f00\u6e90, \u534f\u8bae\u516c\u5f00(\u8fd9\u4f7f\u5f97\u5176\u4ed6\u4eba\u5f00\u59cb\u968f\u610f\u5f00\u53d1\u7b26\u5408\u534f\u8bae\u7684\u7b2c\u4e09\u65b9\u5ba2\u6237\u7aef)<\/p>\n<p>\u6240\u6709\u8282\u70b9\u6784\u5efa\u51faoverlay, \u6bcf\u4e2a\u8282\u70b9\u5927\u69828-10\u4e2a\u90bb\u5c45<\/p>\n<p>\u6d2a\u6cdb(flooding)\u67e5\u8be2: <\/p>\n<p>\u5f53Alice\u9700\u8981\u6587\u4ef6F\u65f6, \u4f1a\u5bf9\u6240\u6709\u90bb\u5c45\u53d1\u8d77\u67e5\u8be2, \u6240\u6709\u90bb\u5c45\u540c\u6837\u4f1a\u8f6c\u53d1\u67e5\u8be2, \u62e5\u6709\u8d44\u6e90\u7684\u8282\u70b9\u4f1a\u56de\u590d\u4fe1\u606f<\/p>\n<p>Alice\u62ff\u5230\u56de\u590d\u4fe1\u606f\u540e, \u53ef\u4ee5\u9009\u62e9peer\u6765\u4e0b\u8f7d<\/p>\n<p>\u4e3a\u4e86\u9632\u6b62\u67e5\u8be2\u73af\u8def, \u8bf7\u6c42\u8fc7\u591a\u53ef\u4ee5<\/p>\n<ul>\n<li>\u8bbe\u7f6eTTL<\/li>\n<li>\u4ee4\u8282\u70b9\u8bb0\u4f4f\u67e5\u8be2<\/li>\n<\/ul>\n<p>\u8282\u70b9\u7684overlay\u8fd9\u6837\u6784\u5efa: <\/p>\n<p>\u5f53\u4e0b\u8f7d\u5ba2\u6237\u7aef\u8f6f\u4ef6\u65f6, \u8f6f\u4ef6\u5185\u7f6e\u4e86\u4e00\u4e9b\u5927\u6982\u7387\u5728\u7ebf\u7684\u8282\u70b9, \u5ba2\u6237\u7aefping\u8fd9\u4e9b\u8282\u70b9, \u8fd9\u4e9b\u8282\u70b9\u4f1aping\u81ea\u5df1\u7684\u90bb\u5c45, \u4ee4\u4ed6\u4eec\u7ee7\u7eed\u8f6c\u53d1ping, \u5e76\u4ee4\u5411\u5ba2\u6237\u56de\u590dpong<\/p>\n<p>\u5ba2\u6237\u7aef\u6839\u636e\u56de\u590d\u7684pong, \u968f\u673a\u6311\u9009\u4e00\u4e9b\u4f5c\u4e3apeer. \u5f53\u5ba2\u6237\u7aef\u4e0b\u7ebf\u65f6, \u8981\u901a\u77e5\u81ea\u5df1\u7684peer, peer\u6536\u5230\u4e0b\u7ebf\u901a\u77e5\u540e, \u4f1a\u8865\u5145\u81ea\u5df1\u7684peer\u6570\u91cf, \u4ee5\u7ef4\u6301\u6b63\u5e38\u8fd0\u884c<\/p>\n<h3>\u975e\u7ed3\u6784\u5316P2P: \u6df7\u5408\u4f53<\/h3>\n<p>KazaA\u662f\u5178\u578b\u7684\u5229\u7528\u4e0d\u5bf9\u79f0\u6027\u7684\u4f8b\u5b50<\/p>\n<p>\u6bcf\u4e2a\u5bf9\u7b49\u65b9\u53ef\u4ee5\u662f\u7ec4\u957f\u6216\u8005\u7ec4\u5458, \u7ec4\u5458\u548c\u7ec4\u957f\u6709TCP\u8fde\u63a5, \u7ec4\u957f\u4e4b\u95f4\u6709TCP\u8fde\u63a5<\/p>\n<p>\u7ec4\u957f\u4f1a\u7ef4\u62a4\u7ec4\u5458\u7684\u4fe1\u606f<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241217133419196.png\" alt=\"image-20241217133419196\" style=\"zoom:33%;\" \/><\/p>\n<p>\u7ec4\u957f\u7ef4\u62a4\u8fd9\u6837\u7684\u8868:  \u6587\u4ef6, \u6587\u672c\u63cf\u8ff0, \u54c8\u5e0c\u503c<\/p>\n<p>\u7528\u6237\u7528\u63cf\u8ff0\u5411\u7ec4\u957f\u53d1\u8d77\u67e5\u8be2, \u7ec4\u957f\u5148\u67e5\u8be2\u81ea\u5df1\u7684\u8868, \u5982\u679c\u6ca1\u6709, \u5219\u8f6c\u53d1\u8bf7\u6c42\u7ed9\u5176\u4ed6\u7ec4\u957f<\/p>\n<h3>BitTorrent<\/h3>\n<p>\u6587\u4ef6\u88ab\u5206\u4e3a\u4e00\u4e2a\u4e2a\u7684\u5757(256KB)<\/p>\n<p>\u7528\u6237\u88ab\u5206\u4e3a\u4e00\u4e2a\u7684Torrent(\u6d2a\u6d41, \u7ec4), \u7ec4\u5185\u4ea4\u6362\u6587\u4ef6\u5757. <\/p>\n<p>\u6bcf\u4e2a\u8282\u70b9\u7ef4\u62a4\u4e00\u4e2aBitmap, \u7ef4\u62a4\u81ea\u5df1\u7684\u6587\u4ef6\u7684\u6bcf\u4e2a\u5757\u7684\u6301\u6709\u60c5\u51b5. \u5b9a\u671f\u6cdb\u6d2a, \u6bcf\u4e2a\u8282\u70b9\u4ea4\u6362Bitmap, \u540c\u6b65\u6587\u4ef6\u6301\u6709\u4fe1\u606f<\/p>\n<p>\u4e00\u4e2a\u65b0\u5ba2\u6237\u7aef\u52a0\u5165Torrent\u4e4b\u540e, Bitmap\u662f\u7a7a\u7684. \u4ed6\u968f\u673a\u8bf7\u6c42\u56db\u4e2a\u7a00\u7f3a\u7684\u5757\u6765\u4e0b\u8f7d, \u5728\u672c\u5730\u7ef4\u62a4(\u542f\u52a8\u8d44\u6e90), \u7136\u540e\u4ed6\u53ef\u4ee5\u6309\u9700\u8bf7\u6c42<\/p>\n<p>\u5728\u8282\u70b9\u5411\u5176\u4ed6\u8282\u70b9\u63d0\u4f9b\u670d\u52a1\u65f6, \u4f18\u5148\u5411\u4e3a\u81ea\u5df1\u63d0\u4f9b\u66f4\u591a\u670d\u52a1\u7684\u8282\u70b9\u5206\u914d\u66f4\u591a\u8d44\u6e90(\u5949\u732e\u8005\u4f18\u5148)<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241217134541333.png\" alt=\"image-20241217134541333\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5982\u679c\u62e5\u6709\u4e86\u6574\u4e2a\u6587\u4ef6, \u5c31\u4f1a\u7559\u4e0b\u79cd\u5b50<\/p>\n<h2>2.7 CDN\u5185\u5bb9\u5206\u53d1\u7f51\u7edc<\/h2>\n<p>\u80cc\u666f: \u4e92\u8054\u7f51\u4e2d70%\u5de6\u53f3\u7684\u6d41\u91cf\u90fd\u88ab\u89c6\u9891\u4e1a\u52a1\u5360\u636e. \u5982\u4f55\u5e76\u53d1\u7684, \u5411\u767e\u4e07\u7ea7\u7684\u7528\u6237\u63d0\u4f9b\u89c6\u9891\u670d\u52a1<\/p>\n<p>\u89e3\u51b3\u65b9\u6848: \u5206\u5e03\u5f0f\u7684, \u5e94\u7528\u5c42\u7684\u5f02\u6784\u89e3\u51b3\u65b9\u6848<\/p>\n<h3>\u6d41\u5316\u64ad\u653e(Streaming)<\/h3>\n<p>\u8fb9\u4e0b\u8fb9\u64ad, \u672c\u5730\u6709\u7f13\u51b2\u533a<\/p>\n<p>DASH\u534f\u8bae: \u57fa\u4e8eHTTP\u7684\u6d41\u5316\u534f\u8bae<\/p>\n<p>\u89c6\u9891\u6bcf8-10s\u5207\u6210\u4e00\u7247, \u5904\u7406\u6210\u4e0d\u540c\u89e3\u6790\u5ea6, \u4e0d\u540c\u538b\u7f29\u6807\u51c6\u7684\u5757. \u8fd9\u6837, \u4e00\u4e2a\u89c6\u9891\u5c31\u6709\u4e86\u591a\u79cd\u7248\u672c<\/p>\n<p>\u7ef4\u62a4\u4e00\u4e2a\u544a\u793a\u6587\u4ef6(manifest file), \u63cf\u8ff0\u6bcf\u4e2a\u5757\u7684\u4fe1\u606f\u548cURL<\/p>\n<p>\u5ba2\u6237\u7aef\u5728\u70b9\u64ad\u65f6\u5019, \u4e0b\u8f7d\u544a\u793a\u6587\u4ef6, \u4e00\u8fb9\u64ad\u653e, \u4e00\u8fb9\u51b3\u5b9a\u540e\u7eed\u8bf7\u6c42\u54ea\u4e9b\u5757(\u6839\u636e\u7f51\u7edc\u548c\u672c\u5730\u73af\u5883\u52a8\u6001\u8bf7\u6c42)<\/p>\n<p>\u6311\u6218: \u4e2d\u5fc3\u670d\u52a1\u5668\u7684\u5e76\u53d1\u538b\u529b\u592a\u5927<\/p>\n<h3>\u5185\u5bb9\u5206\u53d1\u7f51\u7edc(CDN, Content Distribution Networks)<\/h3>\n<p>\u4e92\u8054\u7f51\u5185\u5bb9\u63d0\u4f9b\u5546(\u6bd4\u5982Netfilx, YouTube)\u5411CDN\u516c\u53f8\u8d2d\u4e70\u670d\u52a1, \u5c06\u5185\u5bb9\u63d0\u524d\u90e8\u7f72\u5728\u5206\u5e03\u5f0f\u7684CDN\u670d\u52a1\u5668\u4e0a, \u4f5c\u4e3a\u7f13\u5b58\u8282\u70b9<\/p>\n<p>\u7528\u6237\u5728\u8bf7\u6c42\u5185\u5bb9\u65f6, \u7531CDN\u670d\u52a1\u5668\u63d0\u4f9b<\/p>\n<p>CDN\u516c\u53f8\u6709\u4e24\u79cd\u4e3b\u6d41\u7684\u670d\u52a1\u5668\u90e8\u7f72\u7b56\u7565<\/p>\n<ul>\n<li>enter deep: \u5c06\u670d\u52a1\u5668\u90e8\u7f72\u5728local ISP\u4e2d, \u4f4d\u4e8e\u7f51\u7edc\u5e95\u5c42, \u4e3a\u672c\u5730\u7528\u6237\u63d0\u4f9b\u9ad8\u8d28\u91cf\u670d\u52a1, \u4f46\u662f\u9700\u8981\u66f4\u591a\u786c\u4ef6<\/li>\n<li>bring home: \u90e8\u7f72\u5728\u5c11\u6570\u51e0\u4e2a\u5173\u952e\u4f4d\u7f6e, \u6bd4\u5982ISP\u7684\u8fde\u63a5\u4f4d\u7f6e, \u9700\u8981\u66f4\u5f3a\u6027\u80fd<\/li>\n<\/ul>\n<p>CDN\u8fd0\u884c\u5728\u7f51\u7edc\u7684\u5e94\u7528\u5c42\u4e0a, \u4f4d\u7f6e\u5728\u7f51\u7edc\u7684\u8fb9\u7f18<\/p>\n<h3>OOT\u6311\u6218<\/h3>\n<ul>\n<li>\u7528\u6237\u4ece\u54ea\u4e9bCDN\u8282\u70b9\u83b7\u53d6\u5185\u5bb9<\/li>\n<li>CDN\u9636\u6bb5\u5b58\u50a8\u54ea\u4e9b\u5185\u5bb9<\/li>\n<li>\u7528\u6237\u5728\u7f51\u7edc\u62e5\u585e\u65f6\u7684\u884c\u4e3a<\/li>\n<\/ul>\n<h3>\u7b80\u5355\u7684CDN\u5185\u5bb9\u8bbf\u95ee\u573a\u666f<\/h3>\n<p>Bob\u4f5c\u4e3a\u5ba2\u6237\u7aef, \u8bf7\u6c42\u89c6\u9891<code>http:\/\/netcinema.com\/av10492<\/code><\/p>\n<p>\u89c6\u9891\u5b58\u50a8\u5728CDN, \u4f4d\u4e8e<code>http:\/\/kingcdn.com\/neta338<\/code><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241218134205349.png\" alt=\"image-20241218134205349\" style=\"zoom:33%;\" \/><\/p>\n<p>\u4e0a\u9762\u7684\u56fe\u770b\u7740\u590d\u6742, \u603b\u7ed3\u4e0b\u6765\u8fc7\u7a0b\u4e0d\u96be:<\/p>\n<ol>\n<li>Bob \u7684\u6d4f\u89c8\u5668\u8bf7\u6c42 <code>http:\/\/netcinema.com\/av10492<\/code><\/li>\n<li>\u6d4f\u89c8\u5668\u901a\u8fc7 local DNS \u67e5\u8be2 <code>netcinema.com<\/code> \u7684 IP \u5730\u5740<\/li>\n<li>\u5982\u679c local DNS \u6ca1\u6709\u7f13\u5b58\uff0c\u4f1a\u5411\u4e0a\u5c42\u9012\u5f52\u67e5\u8be2\uff0c\u76f4\u5230\u6743\u5a01 DNS \u670d\u52a1\u5668<\/li>\n<li>\u6743\u5a01 DNS \u670d\u52a1\u5668\u8fd4\u56de\u4e00\u4e2a CNAME \u8bb0\u5f55\uff0c\u4f8b\u5982 <code>kingcdn.com<\/code>\uff0c\u6307\u5411 CDN \u7684\u57df\u540d<\/li>\n<li>\u6d4f\u89c8\u5668\u7ee7\u7eed\u8bf7\u6c42 <code>http:\/\/kingcdn.com\/neta338<\/code><\/li>\n<li>CDN \u7684 DNS \u670d\u52a1\u5668\u6839\u636e Bob \u7684\u7f51\u7edc\u4f4d\u7f6e\u5206\u914d\u4e00\u4e2a\u5408\u9002\u7684 CDN \u8fb9\u7f18\u670d\u52a1\u5668<\/li>\n<li>\u6d4f\u89c8\u5668\u5411\u5206\u914d\u7684 CDN \u8fb9\u7f18\u670d\u52a1\u5668\u53d1\u8d77\u8bf7\u6c42\uff0c\u83b7\u53d6\u8d44\u6e90<\/li>\n<\/ol>\n<p>\u4e0a\u8ff0\u8fc7\u7a0b\u4e2d, \u8def\u5f84\u4ece<code>\/av10492<\/code>\u5230<code>\/neta338<\/code>\u7684\u53d8\u5316\u662fHTTP 301\/302\u91cd\u5b9a\u5411, \u6216\u8005\u540e\u7aef\u4e1a\u52a1\u903b\u8f91\u505a\u7684, \u548cCNAME\u8bb0\u5f55\u6ca1\u6709\u5173\u7cfb<\/p>\n<h2>2.8 TCP\u5957\u63a5\u5b57\u7f16\u7a0b<\/h2>\n<p>\u5957\u63a5\u5b57\u4e86\u89e3\u5373\u53ef<\/p>\n<h2>2.9 UDP\u5957\u63a5\u5b57\u7f16\u7a0b<\/h2>\n<p>\u5957\u63a5\u5b57\u4e86\u89e3\u5373\u53ef<\/p>\n<h1>Chap3. \u4f20\u8f93\u5c42<\/h1>\n<h2>3.1 \u4f20\u8f93\u5c42\u6982\u8ff0\u548c\u670d\u52a1<\/h2>\n<h3>\u4f20\u8f93\u670d\u52a1\u548c\u534f\u8bae<\/h3>\n<p>\u4f20\u8f93\u5c42\u5411\u4e0a\u63d0\u4f9b\u7684\u670d\u52a1\u662f\u5e94\u7528\u8fdb\u7a0b\u4e4b\u95f4\u7684, \u4ee5\u62a5\u6587\u4e3a\u5355\u4f4d\u7684\u903b\u8f91\u901a\u8baf<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241218145447703.png\" alt=\"image-20241218145447703\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u53d1\u9001\u7aef, TCP\/UDP\u4f1a\u5c06\u62a5\u6587\u5206\u6210\u62a5\u6587\u6bb5(segment), \u79fb\u4ea4\u7ed9\u7f51\u7edc\u5c42, \u6240\u4ee5\u6bb5\u662f\u4f20\u8f93\u5c42\u7684PDU<\/p>\n<p>\u5728\u63a5\u6536\u7aef, \u6536\u5230\u62a5\u6587\u6bb5\u540e, \u53bb\u6389\u6bb5\u5934, \u91cd\u65b0\u6392\u5e8f, \u4ee5\u5b57\u8282\u6d41\u7684\u5f62\u5f0f\u4ea4\u7ed9\u5e94\u7528\u5c42. \u4e0a\u9762\u5df2\u7ecf\u63d0\u5230, \u5b57\u8282\u6d41\u53ea\u4fdd\u8bc1\u987a\u5e8f, \u4e0d\u63d0\u4f9b\u754c\u9650<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241218142846379.png\" alt=\"image-20241218142846379\" style=\"zoom:50%;\" \/><\/p>\n<p>\u4f20\u8f93\u5c42\u5411\u4e0a\u63d0\u4f9bTCP\/UDP\u4e24\u79cd\u534f\u8bae, \u4e0b\u65b9\u53ea\u6709\u4e00\u79cdIP\u534f\u8bae. \u7f51\u7edc\u5c42\u53ea\u80fd\u63d0\u4f9b\u4ee5\u5206\u7ec4\u6570\u636e\u62a5\u4e3a\u5355\u4f4d, \u5c3d\u529b\u800c\u4e3a\u7684\u5b58\u50a8\u8f6c\u53d1\u670d\u52a1<\/p>\n<h3>\u4f20\u8f93\u5c42 vs \u7f51\u7edc\u5c42<\/h3>\n<p>\u7f51\u7edc\u5c42\u63d0\u4f9b\u4e3b\u673a\u5230\u4e3b\u673a\u7684\u901a\u8baf, \u4f20\u8f93\u5c42\u7ec6\u5316\u4e3a\u8fdb\u7a0b\u5230\u8fdb\u7a0b\u7684\u901a\u8baf. \u4f20\u8f93\u5c42\u4f9d\u8d56\u4e8e\u7f51\u7edc\u5c42\u7684\u670d\u52a1, \u5e76\u5728\u57fa\u7840\u4e0a\u52a0\u5f3a:<\/p>\n<ul>\n<li>\u4e71\u5e8f -&gt; \u6709\u5e8f<\/li>\n<li>\u660e\u6587 -&gt; \u5bc6\u6587<\/li>\n<li>\u4e22\u5931 -&gt; \u7ea0\u9519<\/li>\n<\/ul>\n<p>\u5de6\u4fa7\u662f\u4f20\u8f93\u5c42\u7684\u7279\u6027, \u7f51\u7edc\u5c42\u5728\u5176\u57fa\u7840\u4e0a, \u5b8c\u5584\u4e86\u529f\u80fd, \u5411\u5e94\u7528\u5c42\u63d0\u4f9b\u66f4\u597d\u7684\u670d\u52a1<\/p>\n<p>\u5e76\u4e0d\u662f\u6240\u6709\u54c1\u8d28\u90fd\u53ef\u4ee5\u52a0\u5f3a: \u5ef6\u8fdf, \u5e26\u5bbd\u7b49\u65e0\u80fd\u4e3a\u529b<\/p>\n<p>\u4f20\u8f93\u5c42\u5728\u7f51\u7edc\u5c42\u57fa\u7840\u4e0a, \u63d0\u4f9b\u7684\u53e6\u4e00\u4e2a\u91cd\u8981\u529f\u80fd\u662f\u590d\u7528\u4e0e\u89e3\u590d\u7528, \u5373, \u4f5c\u4e3a\u53d1\u9001\u7aef\u65f6\u5019, \u8981\u5c06\u5404\u4e2a\u8fdb\u7a0b\u7684\u6570\u636e\u6253\u5305\u53d1\u9001, \u800c\u4f5c\u4e3a\u63a5\u6536\u7aef\u65f6, \u9700\u8981\u63a5\u5305\u6570\u636e, \u6062\u590d\u5230\u8fdb\u7a0b\u7ea7\u522b<\/p>\n<p>\u7c7b\u6bd4Alice\u5bb6\u7ed9Bob\u5bb6\u5199\u4fe1, Alice\u5bb6\u670912\u4eba, Bob\u5bb6\u670912\u4eba, \u603b\u5171\u5c31\u6709144\u5c01\u4fe1<\/p>\n<p>Alice\u5bb6\u7684\u7ba1\u5bb6\u5c06144\u5c01\u4fe1\u6253\u5305\u5728\u4e00\u8d77, \u653e\u5165\u81ea\u5bb6\u4fe1\u7bb1<\/p>\n<p>\u4f5c\u4e3a\u90ae\u653f\u516c\u53f8, \u5c06Alice\u5bb6\u7684\u4fe1\u7edf\u4e00\u5e26\u5230Bob\u5bb6\u5373\u53ef<\/p>\n<p>Bob\u5bb6\u7684\u7ba1\u5bb6\u5728\u4fe1\u7bb1\u6536\u53d6, \u7136\u540e\u533a\u5206\u6bcf\u4e2a\u6210\u5458\u7684\u4fe1, \u4ea4\u7ed9\u5177\u4f53\u7684\u4eba<\/p>\n<h3>\u4f20\u8f93\u5c42\u534f\u8bae<\/h3>\n<p>\u53ef\u9760\u7684, \u4fdd\u5e8f\u7684\u4f20\u8f93: TCP<\/p>\n<ul>\n<li>\u591a\u8def\u590d\u7528, \u89e3\u590d\u7528<\/li>\n<li>\u62e5\u585e\u63a7\u5236<\/li>\n<li>\u6d41\u91cf\u63a7\u5236<\/li>\n<li>\u5efa\u7acb\u8fde\u63a5<\/li>\n<\/ul>\n<p>\u4e0d\u53ef\u9760, \u4e0d\u4fdd\u5e8f\u7684\u4f20\u8f93: UDP<\/p>\n<ul>\n<li>\u591a\u8def\u590d\u7528, \u89e3\u590d\u7528<\/li>\n<li>\u6ca1\u6709\u4e3a\u5c3d\u529b\u800c\u4e3a\u7684IP\u670d\u52a1\u63d0\u4f9b\u66f4\u591a\u52a0\u5f3a<\/li>\n<\/ul>\n<p>\u90fd\u4e0d\u63d0\u4f9b\u7684\u670d\u52a1<\/p>\n<ul>\n<li>\u5ef6\u65f6\u4fdd\u8bc1, \u5e26\u5bbd\u4fdd\u8bc1<\/li>\n<\/ul>\n<h2>3.2 \u591a\u8def\u590d\u7528\u4e0e\u89e3\u590d\u7528<\/h2>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241218151847823.png\" alt=\"image-20241218151847823\" style=\"zoom:33%;\" \/> <\/p>\n<h3>\u591a\u8def\u89e3\u590d\u7528\u7684\u5de5\u4f5c\u539f\u7406<\/h3>\n<p>\u4e3b\u673a\u6536\u5230IP\u6570\u636e\u62a5<\/p>\n<ul>\n<li>\u6bcf\u4e2a\u6570\u636e\u62a5\u6807\u6709\u6e90\u5730\u5740, \u76ee\u6807\u5730\u5740, \u6e90\u7aef\u53e3\u53f7, \u76ee\u6807\u7aef\u53e3\u53f7<\/li>\n<li>\u6bcf\u4e2a\u6570\u636e\u62a5\u627f\u8f7d\u4e00\u4e2a\u4f20\u8f93\u5c42\u62a5\u6587\u6bb5<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241218205009090.png\" alt=\"image-20241218205009090\" style=\"zoom:50%;\" \/><\/p>\n<p>OS\u7ed3\u5408IP\u4e0e\u7aef\u53e3\u53f7\u5c06\u62a5\u6587\u53d1\u9001\u7ed9\u5bf9\u5e94\u7684\u5957\u63a5\u5b57<\/p>\n<p>UDP\u5957\u63a5\u5b57: [\u672c\u5730IP, \u672c\u5730\u7aef\u53e3]<\/p>\n<p>TCP\u5957\u63a5\u5b57: [\u672c\u5730IP, \u672c\u5730\u7aef\u53e3, \u8fdc\u7a0bIP, \u8fdc\u7a0b\u7aef\u53e3]<\/p>\n<p>\u5047\u8bbe\u4e00\u4e2a\u4e3b\u673a\u7684IP\u552f\u4e00, \u6709n\u4e2a\u903b\u8f91\u7aef\u53e3, \u4e0d\u8003\u8651\u5176\u4ed6\u9650\u5236, \u5219:<\/p>\n<ul>\n<li>\u6700\u591a\u5efa\u7acbn\u4e2aUDP\u5957\u63a5\u5b57<\/li>\n<li>\u53ef\u4ee5\u5efa\u7acb\u65e0\u9650\u4e2aTCP\u5957\u63a5\u5b57<\/li>\n<\/ul>\n<h2>3.3 \u65e0\u8fde\u63a5\u4f20\u8f93: UDP<\/h2>\n<p>UDP: \u7528\u6237\u6570\u636e\u62a5\u534f\u8bae<\/p>\n<p>\u5728\u7f51\u7edc\u5c42IP\u534f\u8bae\u7684\u57fa\u7840\u4e0a, \u9664\u4e86\u7528\u591a\u8def\u590d\u7528\u89e3\u590d\u7528\u5b9e\u73b0\u4e86\u8fdb\u7a0b\u5230\u8fdb\u7a0b\u5230\u901a\u8baf, UDP\u6ca1\u6709\u66f4\u8fd1\u4e00\u6b65\u7684\u5176\u4ed6\u529f\u80fd<\/p>\n<ul>\n<li><strong>\u5c3d\u529b\u800c\u4e3a<\/strong>: \u53ef\u80fd\u4e22\u5931, \u53ef\u80fd\u4e71\u5e8f<\/li>\n<li><strong>\u65e0\u8fde\u63a5<\/strong>: \u4e0d\u9700\u8981\u63e1\u624b, \u6bcf\u4e2aUDP\u62a5\u6587\u6bb5\u72ec\u7acb\u5904\u7406<\/li>\n<\/ul>\n<p>UDP\u88ab\u7528\u4e8e\u6d41\u5a92\u4f53, DNS\u7b49\u5e94\u7528(\u4e00\u6b21\u5f80\u8fd4\u641e\u5b9a, \u4e8b\u52a1\u578b\u7684\u5e94\u7528)<\/p>\n<p>UDP\u4e5f\u53ef\u4ee5\u5b9e\u73b0\u53ef\u9760\u4f20\u8f93, \u9700\u8981\u5728\u5e94\u7528\u5c42\u4e0a\u52a0\u5176\u4ed6\u673a\u5236<\/p>\n<p>\u4e3a\u4ec0\u4e48\u8981\u6709UDP?<\/p>\n<ul>\n<li>\u4e0d\u5efa\u7acb\u8fde\u63a5, \u5ef6\u65f6\u5c0f<\/li>\n<li>\u62a5\u6587\u6bb5\u7684\u5934\u90e8\u5f88\u5c0f(\u5f00\u9500\u5c0f, \u53ea\u67098\u5b57\u8282, TCP\u670920\u5b57\u8282)<\/li>\n<\/ul>\n<p>UDP\u662f\u76f4\u80a0\u5b50, \u4e0d\u505a\u62e5\u585e\u63a7\u5236<\/p>\n<h3>UDP\u6821\u9a8c\u548c: \u9519\u8bef\u63a7\u5236<\/h3>\n<p>\u6ca1\u6709\u901a\u8fc7\u6821\u9a8c\u548c\u7684UDP\u62a5\u6587\u6bb5\u4f1a\u88ab\u4e22\u5f03<\/p>\n<p>\u53d1\u9001\u65b9:<\/p>\n<ul>\n<li>\u5c06\u62a5\u6587\u6bb5\u5185\u5bb9\u89c6\u4e3a\u4e00\u4e2a\u768416\u6bd4\u7279\u6574\u6570<\/li>\n<li>\u6821\u9a8c\u548c: \u52a0\u6cd5\u548c, \u8fdb\u4f4d\u56de\u6eda, \u6700\u7ec8\u7ed3\u679c\u53d6\u53cd<\/li>\n<li>\u53d1\u9001\u65b9\u5c06\u6821\u9a8c\u548c\u653e\u5728\u5934\u90e8<\/li>\n<\/ul>\n<p>\u63a5\u6536\u65b9:<\/p>\n<ul>\n<li>\u68c0\u67e5\u6821\u9a8c\u548c, \u5982\u679c\u4e0d\u7b26\u5408\u4e00\u5b9a\u9519\u8bef<\/li>\n<li>\u5982\u679c\u7b26\u5408, \u4e5f\u4e0d\u4e00\u5b9a\u6b63\u786e(\u6b8b\u5b58\u9519\u8bef)<\/li>\n<\/ul>\n<h2>3.4 \u53ef\u9760\u6570\u636e\u4f20\u8f93(RDT)\u539f\u7406<\/h2>\n<h3>\u95ee\u9898\u63cf\u8ff0<\/h3>\n<p>RDT\u5728\u5e94\u7528\u5c42, \u4f20\u8f93\u5c42\u548c\u6570\u636e\u94fe\u8def\u5c42\u90fd\u5f88\u91cd\u8981<\/p>\n<p>\u662f\u7f51\u7edctop10\u95ee\u9898\u4e4b\u4e00<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219134236447.png\" alt=\"image-20241219134236447\" style=\"zoom:50%;\" \/><\/p>\n<p>\u4e0a\u9762\u53f3\u56fe\u53f3\u4e0b\u89d2\u5199\u9519\u4e86, \u662fudt_rcv(), \u5373\u4e0d\u53ef\u9760\u7684\u63a5\u6536<\/p>\n<p>\u8981\u5728\u4e0b\u5c42\u4e0d\u53ef\u9760\u670d\u52a1\u7684\u57fa\u7840\u4e0a, \u5411\u4e0a\u5c42\u63d0\u4f9b\u53ef\u9760\u7684\u670d\u52a1<\/p>\n<p>\u5e95\u5c42channel\u7684\u4e0d\u53ef\u9760\u6027\u51b3\u5b9aRDT\u7684\u590d\u6742\u6027: \u8d8a\u4e0d\u53ef\u9760RDT\u7684\u4efb\u52a1\u5c31\u8d8a\u591a, \u53cd\u4e4b\u5982\u679cchannel\u6bd4\u8f83\u53ef\u9760, \u5219RDT\u5c31\u53ea\u9700\u8865\u9f50\u4e00\u70b9\u5dee\u8ddd\u5373\u53ef<\/p>\n<p>\u63a5\u4e0b\u6765\u6211\u4eec\u5c06:<\/p>\n<ul>\n<li><strong>\u6e10\u8fdb\u5f0f<\/strong>\u7684\u5f00\u53d1RDT\u7684\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9<\/li>\n<li>\u53ea\u8003\u8651\u5355\u5411\u6570\u636e\u4f20\u8f93\n<ul>\n<li>\u4f46\u63a7\u5236\u4fe1\u606f\u662f\u53cc\u5411\u6d41\u52a8\u7684(\u63a5\u6536\u65b9\u786e\u8ba4, \u53cd\u9988\u7b49\u7b49)<\/li>\n<\/ul>\n<\/li>\n<li>\u53cc\u5411\u6570\u636e\u4f20\u8f93\u95ee\u9898\u5b9e\u9645\u4e0a\u662f2\u4e2a\u5355\u5411\u95ee\u9898\u7efc\u5408<\/li>\n<li>\u4f7f\u7528\u6709\u9650\u72b6\u6001\u673a(FSM)\u63cf\u8ff0\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219142726325.png\" alt=\"image-20241219142726325\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>FSM: \u6709\u5411\u56fe, \u7528\u8282\u70b9\u548c\u8fb9\u8868\u793a\u72b6\u6001\u672c\u8eab\u548c\u72b6\u6001\u8fc1\u79fb<\/p>\n<p>\u7528\u5206\u5b50\u8868\u793a\u4e8b\u4ef6, \u5206\u6bcd\u8868\u793a\u8fc1\u79fb\u65f6\u91c7\u53d6\u7684\u52a8\u4f5c<\/p>\n<\/blockquote>\n<h3>RDT 1.0: \u5728\u53ef\u9760\u4fe1\u9053\u4e0a\u7684\u53ef\u9760\u6570\u636e\u4f20\u8f93<\/h3>\n<p>\u5047\u8bbe\u4e0b\u5c42\u4fe1\u9053\u662f\u5b8c\u5168\u53ef\u9760\u7684<\/p>\n<ul>\n<li>\u6ca1\u6709\u6bd4\u7279\u51fa\u9519<\/li>\n<li>\u6ca1\u6709\u5206\u7ec4\u4e22\u5931<\/li>\n<\/ul>\n<p>\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u7684FSM<\/p>\n<ul>\n<li>\u53d1\u9001\u65b9\u5c06\u6570\u636e\u53d1\u9001\u5230\u4e0b\u5c42\u901a\u9053<\/li>\n<li>\u63a5\u6536\u65b9\u4ece\u4e0b\u5c42\u4fe1\u9053\u63a5\u6536\u6570\u636e<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219143603122.png\" alt=\"image-20241219143603122\" style=\"zoom:33%;\" \/><\/p>\n<p>\u56e0\u4e3a\u4e0b\u5c42\u53ef\u9760, RDT 1.0 \u6ca1\u6709\u4ec0\u4e48\u4efb\u52a1, \u5c01\u88c5\u89e3\u5c01\u88c5\u5373\u53ef<\/p>\n<h3>RDT 2.0: \u5177\u6709\u6bd4\u7279\u5dee\u9519\u7684\u4fe1\u9053<\/h3>\n<p>\u4e0b\u5c42\u4fe1\u9053\u53ef\u80fd\u4f1a\u51fa\u9519: \u5206\u7ec4\u4e2d\u7684\u6bd4\u7279\u53cd\u8f6c<\/p>\n<ul>\n<li>\u7528\u6821\u9a8c\u548c\u6765\u68c0\u67e5\u6bd4\u7279\u5dee\u9519<code> D | EDC <\/code><\/li>\n<li>\u63a5\u6536\u65b9\u6821\u9a8c\u6210\u529f\u56de\u590dACK, \u5426\u5219\u56de\u590dNAK, \u6b64\u65f6\u9700\u8981\u91cd\u4f20<\/li>\n<li>\u53d1\u9001\u65b9\u9700\u8981\u4fdd\u7559\u526f\u672c, \u4ee5\u4fbf\u51fa\u9519\u91cd\u4f20<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219144034264.png\" alt=\"image-20241219144034264\" style=\"zoom: 33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219144113837.png\" alt=\"image-20241219144113837\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219144639864.png\" alt=\"image-20241219144639864\" style=\"zoom:66%;\" \/><\/p>\n<h3>RDT 2.0 -&gt; 2.1: \u4fee\u590dACK\u7f3a\u9677<\/h3>\n<p>RDT 2.0\u7684\u7f3a\u9677: ACK, NAK\u4fe1\u606f\u4e5f\u6709\u51fa\u9519\u7684\u53ef\u80fd(\u542c\u4e0d\u6e05)<\/p>\n<p>2.1\u52a0\u5165\u5206\u7ec4\u5e8f\u53f7\u673a\u5236, \u5e76\u4e14\u5728ACK\/NAK\u91cc\u4e5f\u5f15\u5165\u6821\u9a8c\u7f16\u7801<\/p>\n<p>\u4f5c\u4e3a\u53d1\u9001\u65b9:<\/p>\n<ul>\n<li>ACK\/NAK\u542c\u4e0d\u6e05, \u91cd\u53d1\u6d88\u606f, \u76f4\u5230ACK<\/li>\n<\/ul>\n<p>\u4f5c\u4e3a\u63a5\u6536\u65b9:<\/p>\n<ul>\n<li>\u56de\u590dNAK, \u6536\u5230\u91cd\u53d1\u6d88\u606f<\/li>\n<li>\u56de\u590dACK, \u6536\u5230\u91cd\u53d1\u6d88\u606f? \u56e0\u4e3a\u6709\u5e8f\u53f7, \u6240\u4ee5\u77e5\u9053\u8fd9\u6761\u6ca1\u7528, \u4e22\u5f03\u6389, \u7ee7\u7eed\u56de\u590dACK<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219144942570.png\" alt=\"image-20241219144942570\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219145228699.png\" alt=\"image-20241219145228699\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219151234988.png\" alt=\"image-20241219151234988\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u4f5c\u4e3a\u53d1\u9001\u65b9, \u4e24\u4e2a\u5e8f\u5217\u53f7(0, 1)\u5c31\u591f\u7528\u4e86<\/p>\n<\/blockquote>\n<h3>RDT 2.2: NAK-free\u534f\u8bae<\/h3>\n<p>\u5982\u679c\u6bcf\u4e2a\u5206\u7ec4\u90fdACK-NAK\u592a\u9ebb\u70e6\u4e86<\/p>\n<p>\u529f\u80fd\u540cRDT 2.1, \u4f46\u662f\u53ea\u4f7f\u7528\u5e26\u7f16\u53f7\u7684ACK: \u4f5c\u4e3a\u63a5\u6536\u65b9, \u5982\u679c\u7b2c5\u4e2a\u5206\u7ec4\u6821\u9a8c\u5931\u8d25\u4e86,  \u53d1\u9001ACK4\u4e5f\u80fd\u8fbe\u5230\u76f8\u5e94\u7684\u6548\u679c<\/p>\n<p>\u7528\u524d\u4e00\u4e2a\u5206\u7ec4\u7684ACK\u4ee3\u66ff\u5f53\u524d\u5206\u7ec4\u7684NAK, \u786e\u8ba4\u4fe1\u606f\u51cf\u5c11\u4e86\u4e00\u534a<\/p>\n<p>\u8fd9\u4e2a\u505a\u6cd5\u4e3a\u4ee5\u540e\u7684\u534f\u8bae\u4e00\u6b21\u53d1\u9001\u591a\u4e2a\u6570\u636e\u5355\u4f4d\u505a\u4e86\u94fa\u57ab<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219151956549.png\" alt=\"image-20241219151956549\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219151834013.png\" alt=\"image-20241219151834013\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u8d85\u65f6\u91cd\u4f20\u673a\u5236: \u53d1\u9001\u65b9\u53d1\u9001\u4e00\u4e2a\u5206\u7ec4\u540e, \u4e00\u6bb5\u65f6\u95f4\u6ca1\u6709\u6536\u5230\u56de\u590d, \u5219\u8ba4\u4e3a\u4e22\u5931, \u518d\u53d1\u4e00\u904d<\/p>\n<p>\u5982\u679c\u5b9e\u9645\u4e0a\u6ca1\u4e22, \u53d1\u91cd\u590d\u4e86? \u6ca1\u6709\u5f71\u54cd, \u5206\u7ec4\u6709\u5e8f\u53f7, \u63a5\u6536\u65b9\u76f4\u63a5\u4e22\u5f03\u5373\u53ef<\/p>\n<\/blockquote>\n<h3>RDT 3.0: \u5177\u6709\u6bd4\u7279\u5dee\u9519\u4e0e\u5206\u7ec4\u4e22\u5931\u7684\u4fe1\u9053<\/h3>\n<p>\u65b0\u7684\u5047\u8bbe: \u4e0b\u5c42\u4fe1\u9053\u53ef\u80fd\u4f1a\u53cd\u8f6c\u6bd4\u7279, \u6216\u8005\u76f4\u63a5\u4e22\u5931\u4e00\u4e2a\u5206\u7ec4(\u6570\u636e\/ACK), \u6bd4\u5982, \u8def\u7531\u5668\u7f13\u5b58\u961f\u5217\u6ee1\u4e86, \u540e\u9762\u7684\u5206\u7ec4\u76f4\u63a5\u4e22\u6389<\/p>\n<p>RDT 2 \u9762\u4e34\u8fd9\u79cd\u60c5\u51b5\u4f1a\u6b7b\u9501: \u4e24\u65b9\u4e92\u76f8\u7b49<\/p>\n<p>\u6b64\u65f6\u9700\u8981<strong>\u8d85\u65f6\u91cd\u4f20\u673a\u5236<\/strong>, \u65f6\u95f4\u8bbe\u7f6e\u4e3a\u6bd4\u6b63\u5e38\u5f80\u8fd4\u7a0d\u591a\u4e00\u4e9b\u5373\u53ef<\/p>\n<p>\u5728\u6570\u636e\u94fe\u8def\u5c42, \u4f20\u8f93\u5c42\u4e2d, \u8d85\u65f6\u65f6\u95f4\u7b97\u6cd5\u4e0d\u4e00\u6837, \u4e5f\u53ef\u4ee5\u52a8\u6001\u8ba1\u7b97<\/p>\n<ul>\n<li>\u94fe\u8def\u5c42\u662f\u9759\u6001\u7684, \u4f20\u8f93\u5c42\u662f\u52a8\u6001\u7684<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219153553504.png\" alt=\"image-20241219153553504\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219153612922.png\" alt=\"image-20241219153612922\" style=\"zoom:33%;\" \/><\/p>\n<p>\u8d85\u65f6\u5b9a\u65f6\u5668\u7684\u8bbe\u7f6e\u5f88\u6709\u5b66\u95ee: \u4e00\u822c\u8bbe\u7f6e\u4e3a99.9%\u4e22\u5931\u7684\u60c5\u51b5<\/p>\n<p>\u5982\u679c\u4e0d\u5408\u7406(\u8fc7\u65e9\u8d85\u65f6), \u5c31\u4f1a\u9020\u6210\u4e0a\u9762\u53f3\u8fb9\u7684\u60c5\u51b5: ACK1\u6162\u4e86\u4e00\u70b9, \u9020\u6210\u4e86\u4e0d\u540c\u6b65\u5de5\u4f5c. \u6b64\u65f6\u4ecd\u7136\u53ef\u4ee5\u6b63\u5e38\u5de5\u4f5c, \u4f46\u662f\u6548\u7387\u6536\u5230\u5f71\u54cd<\/p>\n<p>RDT 3.0 \u662f\u6bd4\u8f83\u5b8c\u5907\u7684\u534f\u8bae, \u53ef\u4ee5\u5e94\u5bf9\u591a\u79cd\u590d\u6742\u60c5\u51b5, \u4f46\u662f\u5728\u5bf9\u4fe1\u9053\u7684\u5229\u7528\u7387\u8fc7\u4f4e: \u505c-\u7b49\u64cd\u4f5c<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219154718417.png\" style=\"zoom:33%;\" \/><\/p>\n<p>\u4e0a\u56fe\u4e2d, \u53d1\u9001, \u63a5\u6536\u65b9\u5927\u90e8\u5206\u65f6\u95f4\u90fd\u5728\u7b49\u5f85, \u541e\u5410\u91cf\u7684\u74f6\u9888\u5728\u534f\u8bae\u672c\u8eab: \u4e00\u6b21\u53ea\u80fd\u53d1\u4e00\u4e2a<\/p>\n<p>\u8fd9\u79cd\u60c5\u51b5\u7ecf\u5e38\u53d1\u751f\u5728\u4fe1\u9053\u5e26\u5bbd\u5145\u8db3, \u8ddd\u79bb\u9065\u8fdc\u7684\u60c5\u51b5\u4e0b<\/p>\n<h3>\u6d41\u6c34\u7ebf\u534f\u8bae<\/h3>\n<p>\u5141\u8bb8\u53d1\u9001\u65b9\u5728\u672a\u7ecf\u786e\u8ba4\u7684\u524d\u63d0\u4e0b\u4e00\u6b21\u53d1\u9001\u591a\u4e2a\u5206\u7ec4, \u63d0\u9ad8\u4fe1\u9053\u5229\u7528\u7387<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219155323406.png\" alt=\"image-20241219155323406\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>\u5fc5\u987b\u589e\u52a0\u5e8f\u53f7\u8303\u56f4: \u7528\u591a\u4e2abit\u8868\u793a\u5206\u7ec4\u5e8f\u53f7<\/li>\n<li>\u53d1\u9001\u65b9\/\u63a5\u6536\u65b9\u9700\u8981\u6709\u7f13\u51b2\u533a\n<ul>\n<li>\u53d1\u9001\u65b9\u7f13\u51b2: \u6ca1\u6709\u5f97\u5230\u786e\u8ba4, \u9700\u8981\u91cd\u4f20<\/li>\n<li>\u63a5\u6536\u65b9\u7f13\u51b2: \u5339\u914d\u4e0a\u5c42\u53d6\u7528\u6570\u636e\u901f\u5ea6, \u5904\u7406\u4e71\u5e8f\u95ee\u9898<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219155720629.png\" alt=\"image-20241219155720629\" style=\"zoom:33%;\" \/><\/p>\n<p>\u6709\u4e24\u79cd\u901a\u7528\u7684\u6d41\u6c34\u7ebf\u534f\u8bae: <\/p>\n<ul>\n<li>\u56de\u9000N\u6b65(GBN)<\/li>\n<li>\u9009\u62e9\u91cd\u4f20(SR)<\/li>\n<\/ul>\n<h3>\u6ed1\u52a8\u7a97\u53e3(Sliding window)\u534f\u8bae<\/h3>\n<p>\u5f53S\u65b9window=1, R\u65b9window=1\u65f6, \u9000\u5316\u4e3a\u4e86\u505c\u6b62\u7b49\u5f85\u534f\u8bae(Stop &amp; Wait), RDT 3.0\u5c31\u662f\u8fd9\u6837\u7684\u534f\u8bae<\/p>\n<p>\u5f53S\u65b9window&gt;1, R\u65b9window=1\u65f6, \u662fGBN\u534f\u8bae<\/p>\n<p>\u5f53S\u65b9window&gt;1, R\u65b9window&gt;1\u65f6, \u662fSR\u534f\u8bae<\/p>\n<p>GBN, SR\u90fd\u662f\u6d41\u6c34\u7ebf\u534f\u8bae<\/p>\n<p>\u53d1\u9001\u7f13\u51b2\u533a: \u5185\u5b58\u4e2d\u7684\u4e00\u4e2a\u533a\u57df, \u5b58\u50a8\u5373\u5c06\u53d1\u9001\u7684\u5206\u7ec4, \u548c\u6ca1\u6709ACK\u7684\u5206\u7ec4<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219160531895.png\" alt=\"image-20241219160531895\" style=\"zoom:33%;\" \/> <img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219160747637.png\" alt=\"image-20241219160747637\" style=\"zoom:33%;\" \/><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219160916419.png\" alt=\"image-20241219160916419\" style=\"zoom:33%;\" \/><\/p>\n<p>\u63a5\u6536\u7a97\u53e3: \u63a5\u6536\u7f13\u51b2\u533a, \u8868\u793a\u6b63\u5728\u7b49\u5f85\u63a5\u6536\u7684\u5206\u7ec4<\/p>\n<ul>\n<li>size = 1, \u4e0d\u80fd\u4e71\u5e8f, GBN<\/li>\n<li>size &gt; 1, \u53ef\u4ee5\u4e71\u5e8f, SR<\/li>\n<\/ul>\n<p>\u843d\u5728\u7a97\u53e3\u5185\u7684\u7f16\u53f7\u7684\u5206\u7ec4\u4f1a\u56de\u590dACK, \u800c\u843d\u5728\u63a5\u6536\u7a97\u53e3\u5916\u7684\u7f16\u53f7\u7684\u5206\u7ec4\u4f1a\u88ab\u629b\u5f03\u6389, \u5e76\u56de\u590d\u5f53\u524d\u6536\u5230\u987a\u5e8f\u5230\u6765\u7684, \u6700\u9ad8\u5206\u7ec4\u7684\u786e\u8ba4<\/p>\n<blockquote>\n<p>\u5047\u8bbesize=2, \u5df2\u7ecf\u6536\u5230\u4e861, \u6b63\u5728\u7b49\u5f852, 3, \u6b64\u65f6\u6536\u5230\u4e865, 5\u4f1a\u88ab\u629b\u5f03\u6389, \u5e76\u56de\u590dack=1<\/p>\n<\/blockquote>\n<p>\u5f53\u4f4e\u5e8f\u53f7\u88abACK\u540e, \u7a97\u53e3\u4f1a\u6ed1\u52a8<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219162552512.png\" alt=\"image-20241219162552512\" style=\"zoom:33%;\" \/><\/p>\n<p>SR\u7684\u786e\u8ba4\u4e0d\u5177\u5907\u7d2f\u8ba1\u786e\u8ba4\u7684\u542b\u4e49, \u800c\u662f\u72ec\u7acb\u786e\u8ba4, \u5373, ACK=3\u53ea\u4ee3\u8868\u786e\u8ba43, \u4e0d\u660e\u786e1, 2\u4e24\u4e2a\u5206\u7ec4\u7684\u72b6\u6001<\/p>\n<p>\u76f8\u5bf9\u7684, GBN\u7684\u786e\u8ba4\u5177\u5907\u7d2f\u8ba1\u542b\u4e49<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219162759343.png\" alt=\"image-20241219162759343\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219163422966.png\" alt=\"image-20241219163422966\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219163635057.png\" alt=\"image-20241219163635057\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219163944731.png\" alt=\"image-20241219163944731\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219164331023.png\" alt=\"image-20241219164331023\" style=\"zoom:33%;\" \/><\/p>\n<h2>3.5 \u9762\u5411\u8fde\u63a5\u7684\u4f20\u8f93: TCP<\/h2>\n<h3>TCP\u6982\u8ff0<\/h3>\n<p>\u70b9\u5bf9\u70b9: \u4e00\u4e2a\u53d1\u9001\u65b9, \u4e00\u4e2a\u63a5\u6536\u65b9<\/p>\n<p>\u53ef\u9760\u7684, \u4fdd\u5e8f\u7684\u5b57\u8282\u6d41: \u6ca1\u6709\u62a5\u6587\u8fb9\u754c<\/p>\n<p>\u7ba1\u9053\u5316(\u6d41\u6c34\u7ebf): TCP\u62e5\u585e\u63a7\u5236\u548c\u6d41\u91cf\u63a7\u5236\u7ba1\u7406\u7a97\u53e3\u5927\u5c0f<\/p>\n<p>\u53d1\u9001\u548c\u63a5\u6536\u7f13\u5b58<\/p>\n<p>\u5168\u53cc\u5de5\u6570\u636e: \u4e00\u4e2a\u8fde\u63a5\u53cc\u5411\u6d41\u52a8, MSS: \u6700\u5927\u62a5\u6587\u6bb5<\/p>\n<p>\u9762\u5411\u8fde\u63a5: \u6b63\u5f0f\u901a\u4fe1\u524d, \u8981\u63e1\u624b, \u7ef4\u6301\u72b6\u6001<\/p>\n<p>\u6d41\u91cf\u63a7\u5236: \u53d1\u9001\u65b9\u4e0d\u4f1a\u6df9\u6ca1\u63a5\u6536\u65b9<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219220306778.png\" alt=\"image-20241219220306778\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u5e94\u7528\u5c42\u53d1\u9001\u65b9, \u5404\u4e2a\u5e94\u7528\u7a0b\u5e8f\u6709\u81ea\u5df1\u7684\u534f\u8bae, \u4ee5\u5404\u79cd\u683c\u5f0f\u5c01\u88c5\u6570\u636e, \u7136\u540e\u53d1\u9001\u7ed9TCP\u5957\u63a5\u5b57. \u7a7f\u8fc7\u5957\u63a5\u5b57\u540e, \u7edf\u4e00\u88ab\u5f53\u4f5c\u5b57\u8282\u6d41\u770b\u5f85<\/p>\n<p>TCP\u957f\u957f\u7684\u5b57\u8282\u6d41\u6765\u81ea\u4e8e\u5957\u63a5\u5b57, \u5728\u53d1\u9001\u65f6\u4f1a\u5207\u6210size&lt;=MSS\u7684\u62a5\u6587\u6bb5, \u88c5\u4e0aTCP\u5934\u90e8\u53d1\u9001\u51fa\u53bb<\/p>\n<h3>TCP\u62a5\u6587\u7ed3\u6784<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219220325331.png\" alt=\"image-20241219220325331\" style=\"zoom:50%;\" \/><\/p>\n<p>\u4e0a\u9762\u7684\u5e8f\u53f7\u662f\u4ee5\u5b57\u8282\u4e3a\u7f16\u53f7\u7684\u5e8f\u53f7, \u662f\u8fd9\u4e2a\u62a5\u6587\u6bb5\u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u5728\u6574\u4e2a\u5b57\u8282\u6d41\u4e2d\u7684\u504f\u79fb\u91cf<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219220904148.png\" alt=\"image-20241219220904148\" style=\"zoom:50%;\" \/><\/p>\n<p>\u8fd9\u662f\u56e0\u4e3aTCP\u662f\u9762\u5411\u5b57\u8282\u6d41\u7684\u534f\u8bae, \u800c\u4e0d\u662f\u9762\u5411\u62a5\u6587\u6bb5\u7684\u534f\u8bae. \u8d77\u59cb\u5b57\u8282\u5e8f\u53f7x\u901a\u5e38\u662f\u968f\u673a\u7684, \u8fd9\u6709\u52a9\u4e8e\u9632\u6b62\u65e7\u7684TCP\u8fde\u63a5\u5e72\u6270<\/p>\n<p>\u5728TCP\u4e2d, ACK\u662f\u7d2f\u79ef\u786e\u8ba4, ACK=555\u8868\u793a\u63a5\u6536\u5230\u4e86554\u53ca\u4ee5\u524d\u7684\u5168\u90e8\u6570\u636e, \u8868\u793a\u671f\u5f85, \u540c\u6837\u7684\u662f\u5bf9\u5b57\u8282\u7684\u8ba1\u6570, \u800c\u4e0d\u662f\u62a5\u6587\u6bb5<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219221624872.png\" alt=\"image-20241219221624872\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219222940438.png\" alt=\"image-20241219222940438\" style=\"zoom:33%;\" \/><\/p>\n<p>TCP\u7684\u8d85\u65f6\u65f6\u95f4\u662f\u81ea\u9002\u5e94\u7684<\/p>\n<h3>TCP\u7684\u5f80\u8fd4\u5ef6\u65f6(RTT)\u548c\u8d85\u65f6<\/h3>\n<p>TCP\u9762\u4e34\u7684\u5b9e\u9645\u901a\u8baf\u73af\u5883\u5f88\u590d\u6742, RTT\u53ef\u80fd\u65f6\u9ad8\u65f6\u4f4e: \u9700\u8981\u6d4b\u91cfRTT<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241219224352679.png\" alt=\"image-20241219224352679\" style=\"zoom:33%;\" \/><\/p>\n<h3>TCP: \u53ef\u9760\u6570\u636e\u4f20\u8f93<\/h3>\n<p>TCP\u4f7f\u7528\u7ba1\u9053\u5316\u7684\u62a5\u6587\u6bb5<\/p>\n<ul>\n<li>\u7c7b\u4f3cGBN\/SR, \u4e00\u6b21\u53d1\u591a\u7ec4<\/li>\n<\/ul>\n<p>TCP\u4f7f\u7528\u7d2f\u8ba1\u786e\u8ba4ACK<\/p>\n<ul>\n<li>\u7c7b\u4f3cGBN, \u4f46TCP\u7684ACK\u8868\u793a\u671f\u671b<\/li>\n<\/ul>\n<p>TCP\u4f7f\u7528\u5355\u4e2a\u91cd\u4f20\u5b9a\u65f6\u5668<\/p>\n<ul>\n<li>\u7c7b\u4f3cGBN, \u6bcf\u4e2a\u7a97\u53e3\u6709\u4e00\u4e2a\u5b9a\u65f6\u5668, \u8d85\u65f6\u5168\u90e8\u91cd\u53d1<\/li>\n<\/ul>\n<p>TCP\u4e0d\u89c4\u5b9a\u4e71\u5e8f\u5904\u7406<\/p>\n<ul>\n<li>\u5728\u5b9e\u9645\u60c5\u51b5\u4e2d, \u7ecf\u5e38\u7c7b\u4f3cSR, \u6709\u63a5\u6536\u7a97\u53e3<\/li>\n<\/ul>\n<blockquote>\n<p>\u540d\u8bcd\u89e3\u91ca:<\/p>\n<ul>\n<li>\n<p>cwnd(Congestion Window), \u62e5\u585e\u7a97\u53e3<\/p>\n<\/li>\n<li>\n<p>rwnd(Receiver Window), \u63a5\u6536\u7a97\u53e3<\/p>\n<\/li>\n<\/ul>\n<\/blockquote>\n<h3>TCP\u53d1\u9001\u65b9\u4e8b\u4ef6<\/h3>\n<p>\u5b9a\u65f6\u5668\u548c\u6700\u65e9\u672a\u786e\u8ba4\u7684\u62a5\u6587\u6bb5\u5173\u8054<\/p>\n<p>\u8d85\u65f6\u91cd\u4f20: \u5982\u679c\u8d85\u65f6, \u91cd\u4f20\u6700\u8001\u62a5\u6587\u6bb5, \u5373\u7a97\u53e3\u5185\u7684\u7b2c\u4e00\u4e2a\u62a5\u6587\u6bb5, \u91cd\u65b0\u542f\u52a8\u5b9a\u65f6\u5668<\/p>\n<p>\u6536\u5230\u786e\u8ba4: \u66f4\u65b0\u786e\u8ba4\u5e8f\u53f7, \u5982\u679c\u8fd8\u6709\u672a\u786e\u8ba4\u7684\u62a5\u6587\u6bb5, \u91cd\u65b0\u542f\u52a8\u5b9a\u65f6\u5668<\/p>\n<p>\u4e09\u4e2a\u76f8\u540cACK, \u7acb\u5373\u91cd\u4f20\u8981\u6c42\u7684<strong>\u5355\u4e2a\u62a5\u6587\u6bb5<\/strong><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220002110201.png\" alt=\"image-20241220002110201\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220003411847.png\" alt=\"image-20241220003411847\" style=\"zoom:33%;\" \/><\/p>\n<h3>TCP\u63a5\u6536\u65b9\u4e8b\u4ef6<\/h3>\n<p>\u6b63\u5e38\u60c5\u51b5\u4e0b, \u6709\u9690\u5fcd\u4e0d\u53d1\u7684\u89c4\u5219, \u5c3d\u91cf\u51cf\u5c11\u5bf9\u53d1\u9001\u65b9\u7684\u5e72\u6270: \u8f85\u52a9\u8ba1\u65f6\u5668<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220002817392.png\" alt=\"image-20241220002817392\" style=\"zoom:33%;\" \/><\/p>\n<h3>TCP\u6d41\u91cf\u63a7\u5236<\/h3>\n<p>\u63a5\u6536\u65b9\u63a7\u5236\u53d1\u9001\u65b9, \u4e0d\u8ba9\u53d1\u9001\u65b9\u4e00\u6b21\u53d1\u9001\u592a\u591a, \u592a\u5feb, \u4ee5\u81f3\u4e8e\u8ba9\u63a5\u6536\u65b9\u81ea\u5df1\u7684\u7f13\u51b2\u533a\u6ea2\u51fa<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220173200868.png\" alt=\"image-20241220173200868\" style=\"zoom:33%;\" \/><\/p>\n<p>\u63a5\u6536\u65b9\u5728\u56de\u590d\u6d88\u606f\u65f6, \u5728TCP\u62a5\u6587\u5934\u90e8\u4e2d\u7684rwnd\u5b57\u6bb5\u901a\u544a\u81ea\u5df1\u7a7a\u95f2\u7684buffer\u5927\u5c0f<\/p>\n<ul>\n<li>RcvBuffer\u901a\u8fc7socket\u9009\u9879\u8bbe\u7f6e, \u7ecf\u5178\u5927\u5c0f\u4e3a4096\u5b57\u8282<\/li>\n<li>OS\u6709\u65f6\u4f1a\u81ea\u52a8\u8c03\u6574RcvBuffer<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220174213040.png\" alt=\"image-20241220174213040\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5f53\u63a5\u6536\u65b9\u4e22\u5f03\u4e71\u5e8f\u62a5\u6587\u7684\u65f6\u5019: RcvWindow = RcvBuffer &#8211; [LastByteRcvd &#8211; LastByteRead]<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220174517536.png\" alt=\"image-20241220174517536\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>TCP data in buffer\u662f\u5e94\u7528\u6ca1\u6765\u5f97\u53ca\u8bfb\u8bfb\u6570\u636e<\/li>\n<\/ul>\n<blockquote>\n<p>\u634e\u5e26\u6280\u672f(Piggybacking): \u5728\u5168\u53cc\u5de5\u901a\u8baf\u4e2d\u6548\u679c\u6700\u4f73, \u5373, \u4e24\u4e2a\u5bf9\u7b49\u4f53\u76f8\u4e92\u6536\u53d1\u6d88\u606f, \u6b64\u65f6ACK\u548cData\u5197\u4f59\u7a0b\u5ea6\u5f88\u5927, \u53ef\u4ee5\u5c06ACK\u548c\u8981\u53d1\u9001\u7684Data\u653e\u5728\u4e00\u8d77\u53d1\u9001, \u8282\u7701\u6027\u80fd<\/p>\n<\/blockquote>\n<h3>TCP\u8fde\u63a5\u7ba1\u7406: 3\u6b21\u63e1\u624b<\/h3>\n<p>\u5728\u6b63\u5f0f\u4ea4\u6362\u6570\u636e\u4e4b\u524d, \u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u63e1\u624b\u5efa\u7acb\u901a\u4fe1\u5173\u7cfb<\/p>\n<ul>\n<li>\u53cc\u65b9\u540c\u610f\u8fde\u63a5<\/li>\n<li>\u7ea6\u5b9a\u8fde\u63a5\u53c2\u6570: \u7f13\u51b2\u533a, \u53cc\u65b9\u521d\u59cb\u5b57\u8282\u7f16\u53f7<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220174935315.png\" alt=\"image-20241220174935315\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220175157713.png\" alt=\"image-20241220175157713\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220175609328.png\" alt=\"image-20241220175609328\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220175835193.png\" alt=\"image-20241220175835193\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u968f\u673a\u521d\u59cb\u5e8f\u53f7x, y\u7684\u4f5c\u7528: \u5047\u8bbe\u5ba2\u6237\u7aef\u7528555\u7aef\u53e3\u4e0eWeb\u670d\u52a1\u5668\u768480\u7aef\u53e3\u8fde\u63a5, \u6b63\u5e38\u901a\u8baf\u671f\u95f4, \u5ba2\u6237\u7aef\u91cd\u53d1\u4e86\u4e00\u4e2a\u5206\u7ec4P, \u5206\u7ec4P\u56e0\u4e3a\u7f51\u7edc\u539f\u56e0\u6ede\u7559\u5728\u8def\u4e0a, \u5f88\u4e45\u90fd\u6ca1\u6709\u5230\u8fbe, \u540e\u6765\u8fde\u63a5\u88ab\u5173\u95ed<\/p>\n<p>\u5f88\u4e45\u4e4b\u540e, \u5ba2\u6237\u7aef\u91cd\u65b0\u7528555\u7aef\u53e3\u4e0eWeb\u670d\u52a1\u5668\u768480\u7aef\u53e3\u8fde\u63a5, \u8fde\u63a5\u5efa\u7acb\u540e, \u5206\u7ec4P\u59d7\u59d7\u6765\u8fdf, \u6b64\u65f6\u670d\u52a1\u5668\u6709\u53ef\u80fd\u8bef\u4ee5\u4e3aP\u662f\u5f53\u524d\u8fde\u63a5\u7684\u6570\u636e(\u5b9e\u9645\u4e0a\u662f\u8001\u8fde\u63a5\u7684\u65e0\u6548\u6570\u636e)<\/p>\n<p>\u6709\u4e86x, y, \u6211\u4eec\u5c31\u53ef\u4ee5\u8bc6\u522b\u5206\u7ec4P\u662f\u5426\u662f\u5f53\u524d\u8fde\u63a5\u7684\u6570\u636e<\/p>\n<\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220180715640.png\" alt=\"image-20241220180715640\" style=\"zoom:33%;\" \/><\/p>\n<h3>TCP\u8fde\u63a5\u7684\u62c6\u9664(\u4e0d\u5b8c\u7f8e\u7684\u56db\u6b21\u63e1\u624b\u539f\u5219)<\/h3>\n<p>\u5b9e\u9645\u4e0a\u662f\u4e24\u4e2a\u534a\u8fde\u63a5\u7684\u5206\u522b\u62c6\u9664, \u4f46\u6709\u53ef\u80fd\u4f1a\u51fa\u73b0\u4e00\u65b9\u7ef4\u6301\u534a\u8fde\u63a5\u7684\u60c5\u51b5: \u6700\u540e\u4e00\u6b21\u901a\u8baf\u603b\u662f\u4e0d\u53ef\u9760\u7684<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220181247121.png\" alt=\"image-20241220181247121\" style=\"zoom:33%;\" \/><\/p>\n<p>\u4e3b\u52a8\u65b9\u7684\u6700\u540e\u4e00\u6b21ACK\u53d1\u9001\u540e, \u6709\u53ef\u80fd\u4e22\u5931\u4e86, \u4f46\u662f\u81ea\u5df1\u65e0\u6cd5\u77e5\u9053, \u5173\u95ed\u4e86\u8fde\u63a5. \u6b64\u65f6\u88ab\u52a8\u65b9\u4f1a\u89e6\u53d1\u8d85\u65f6\u91cd\u4f20FIN, \u591a\u6b21\u91cd\u4f20\u5931\u8d25\u540e, \u624d\u4f1a\u5173\u95ed\u8fde\u63a5<\/p>\n<h2>3.6 \u62e5\u585e\u63a7\u5236\u539f\u7406<\/h2>\n<p>\u592a\u591a\u7684\u6570\u636e\u9700\u8981\u4f20\u8f93, \u8d85\u8fc7\u4e86\u7f51\u7edc\u7684\u627f\u8f7d\u80fd\u529b<\/p>\n<ul>\n<li><strong>\u6d41\u91cf\u63a7\u5236<\/strong>\u662f\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u7684\u534f\u8c03<\/li>\n<li><strong>\u62e5\u585e\u63a7\u5236<\/strong>\u662f\u53d1\u9001\u65b9\u548c\u7f51\u7edc\u7684\u534f\u8c03<\/li>\n<\/ul>\n<p>\u62e5\u585e\u63a7\u5236\u4e5f\u662f\u7f51\u7edcTOP10\u95ee\u9898, \u62e5\u585e\u7684\u4e3b\u8981\u539f\u56e0\u548c\u8868\u73b0\u6709<\/p>\n<ul>\n<li><strong>\u7f51\u7edc\u5e26\u5bbd\u74f6\u9888<\/strong>: \u5ef6\u65f6\u65e0\u9650\u589e\u5927<\/li>\n<li><strong>\u8def\u7531\u5668\u7f13\u51b2\u533a\u6ea2\u51fa<\/strong>: \u4e22\u5305<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220182910283.png\" alt=\"image-20241220182910283\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220183118648.png\" alt=\"image-20241220183118648\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u62e5\u585e\u7684\u65f6\u5019, \u9891\u7e41\u7684\u8d85\u65f6\u91cd\u4f20\u4f1a\u8ba9\u7f51\u7edc\u4e2d\u6709\u6548\u4fe1\u606f\u7684\u5360\u6bd4\u6781\u5177\u4e0b\u964d: \u4e3a\u4e86\u8ba9\u63a5\u6536\u65b9\u8fbe\u5230\u6709\u6548\u7f51\u7edc\u8f93\u51falambda, \u4e5f\u8bb8\u9700\u8981\u6570\u500d\u7684\u8f93\u5165<\/p>\n<p>\u7f51\u7edc\u62e5\u585e\u7684\u53d1\u751f\u4e0d\u662f\u7ebf\u6027\u7684, \u5982\u679c\u4e0d\u52a0\u4ee5\u63a7\u5236, \u53ea\u8981\u51fa\u73b0\u4e00\u70b9\u62e5\u585e, \u4f1a\u4f7f\u5404\u4e2a\u53d1\u9001\u65b9\u704c\u5165\u65e0\u6548\u4fe1\u606f, \u6301\u7eed\u52a0\u5267\u62e5\u585e\u60c5\u51b5, \u5bfc\u81f4\u5728\u6b63\u5e38\u5de5\u4f5c\u4e2d\u77ac\u95f4\u5d29\u6e83<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220184101193.png\" alt=\"image-20241220184101193\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u4e0a\u56fe\u4e2d, \u4e3b\u673a\u5bf9\u8ddd\u79bb\u8f83\u8fd1\u7684\u8df3\u7684\u8def\u7531\u5668\u6709\u4f18\u52bf, \u4f1a\u6324\u5360\u5176\u4ed6\u4e3b\u673a\u7684\u8bf7\u6c42, \u8ba9\u4ed6\u4eec\u88ab\u4e22\u5f03, \u4f46\u662f\u5728\u8fdc\u7aef\u7684\u8df3, \u53c8\u53cd\u800c\u88ab\u5176\u4ed6\u4e3b\u673a\u6324\u5360, \u81ea\u5df1\u88ab\u4e22\u5f03. \u8fd9\u79cd\u76f8\u4e92\u5236\u7ea6\u7684\u60c5\u51b5\u4e0b, \u65e0\u8bba\u5404\u4e2a\u4e3b\u673a\u5982\u4f55\u52aa\u529b\u7684\u6ce8\u5165\u6570\u636e, \u6574\u4e2a\u7f51\u7edc\u90fd\u6ca1\u6709\u8f93\u51fa: \u7f51\u7edc\u6b7b\u9501<\/p>\n<p>\u53c8\u4e00\u4e2a\u62e5\u585e\u7684\u4ee3\u4ef7: \u4e00\u4e2a\u5206\u7ec4\u88ab\u629b\u5f03\u65f6, \u4e4b\u524d\u4e0a\u6e38\u7684\u8d44\u6e90\u5168\u90e8\u88ab\u6d6a\u8d39\u6389\u4e86<\/p>\n<h3>\u62e5\u585e\u63a7\u5236\u65b9\u6cd5<\/h3>\n<ul>\n<li>\u7aef\u5230\u7aef\u7684\u63a7\u5236: \u7aef\u7cfb\u7edf\u901a\u8fc7\u5ef6\u8fdf\u548c\u4e22\u5305\u5224\u65ad\u662f\u5426\u62e5\u585e(TCP\u7684\u65b9\u6cd5)<\/li>\n<li>\u7f51\u7edc\u8f85\u52a9\u63a7\u5236: \u7f51\u7edc\u7ed9\u7aef\u7cfb\u7edf\u4e00\u5b9a\u663e\u5f0f\u53cd\u9988<\/li>\n<\/ul>\n<h3>\u7f51\u7edc\u8f85\u52a9\u63a7\u5236\u5b9e\u4f8b: ATM ABR\u62e5\u585e\u673a\u5236<\/h3>\n<p>ABR(Available bit rate): \u5f39\u6027\u670d\u52a1\u6a21\u5f0f<\/p>\n<ul>\n<li>\u5982\u679c\u8def\u5f84\u6ca1\u6709\u538b\u529b, \u53d1\u9001\u65b9\u53ef\u4ee5\u4f7f\u7528\u5168\u90e8\u53ef\u7528\u5e26\u5bbd<\/li>\n<li>\u5982\u679c\u8def\u5f84\u62e5\u585e, \u9650\u5236\u53d1\u9001\u65b9\u7684\u6700\u5927\u53d1\u9001\u5e26\u5bbd<\/li>\n<\/ul>\n<p>\u7f51\u7edc\u4e2d\u53d1\u9001\u7684\u57fa\u672c\u5355\u4f4d\u53eb\u4fe1\u5143, \u6709\u4e24\u79cd, \u6570\u636e\u4fe1\u5143\u548c\u8d44\u6e90\u7ba1\u7406\u4fe1\u5143(RM cell). <\/p>\n<p>\u8d44\u6e90\u7ba1\u7406\u4fe1\u5143\u5728\u53d1\u9001\u7aef\u95f4\u9694\u63d2\u5165, \u5728\u63a5\u6536\u7aef\u76f4\u63a5\u8fd4\u56de, \u5728\u7f51\u7edc\u6838\u5fc3\u88ab\u4ea4\u6362\u673a\u6253\u4e0a\u6807\u5fd7<\/p>\n<ul>\n<li>NI bit: \u8f7b\u5fae\u62e5\u585e, \u4e0d\u8981\u518d\u589e\u52a0\u6ce8\u5165\u901f\u7387<\/li>\n<li>CI bit: \u660e\u663e\u62e5\u585e, \u964d\u4f4e\u6ce8\u5165\u901f\u7387<\/li>\n<li>ER: \u663e\u5f0f\u901f\u7387, \u53d1\u9001\u65b9\u586b\u5199, \u4ea4\u6362\u673a\u4fee\u6539<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220195258614.png\" alt=\"image-20241220195258614\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u4e00\u6b21Round trip\u4e2d, \u53d1\u9001\u65b9\u901a\u8fc7\u4f20\u56de\u7684RM cell\u6765\u52a8\u6001\u8c03\u6574\u6ce8\u5165\u901f\u7387<\/p>\n<h2>3.7 TCP\u62e5\u585e\u63a7\u5236<\/h2>\n<h3>TCP\u62e5\u585e\u63a7\u5236\u673a\u5236<\/h3>\n<p>\u5728TCP\u4e2d, \u7f51\u7edc\u4e0d\u63d0\u4f9b\u53cd\u9988\u4fe1\u606f, \u800c\u662f\u91c7\u7528\u7aef\u5230\u7aef\u7684<strong>\u62e5\u585e\u63a7\u5236<\/strong><\/p>\n<p>\u8fd9\u79cd\u505a\u6cd5\u964d\u4f4e\u4e86\u7f51\u7edc\u6838\u5fc3\u7684\u590d\u6742\u5ea6, \u5c06\u590d\u6742\u5ea6\u8f6c\u79fb\u5230\u8fb9\u7f18<\/p>\n<h3>\u53d1\u9001\u65b9\u63a2\u6d4b\u62e5\u585e<\/h3>\n<p>\u6bcf\u4e2a\u6bb5\u786e\u8ba4\u8d85\u65f6(\u4e22\u5931)\u4e86: \u5927\u6982\u7387\u62e5\u585e<\/p>\n<ul>\n<li>\u53ef\u80fd\u662f\u7f51\u7edc\u5df2\u7ecf\u62e5\u585e, \u8def\u7531\u5668\u7f13\u5b58\u6ea2\u51fa(\u5927\u6982\u7387)<\/li>\n<li>\u53ef\u80fd\u662f\u56e0\u4e3a\u51fa\u9519, \u5728\u6821\u9a8c\u4e2d\u88ab\u4e22\u5f03(\u5c0f\u6982\u7387)<\/li>\n<\/ul>\n<p>3\u6b21\u91cd\u590dACK: \u8f7b\u5fae\u62e5\u585e<\/p>\n<ul>\n<li>3\u6b21\u91cd\u590dACK\u4ee3\u8868\u63a5\u6536\u65b9\u6b63\u5728\u4e71\u5e8f\u6536\u5230\u540e\u7eed\u62a5\u6587\u6bb5, \u4f46\u662fACK\u7684\u6bb5\u4e00\u76f4\u6ca1\u6709\u62b5\u8fbe<\/li>\n<li>\u76ee\u6807\u6bb5\u53ef\u80fd\u5df2\u7ecf\u4e22\u5931, \u4f46\u662f\u7531\u4e8e\u8d85\u65f6\u65f6\u95f4\u6bd4\u8f83\u4fdd\u5b88, \u6682\u672a\u8d85\u65f6<\/li>\n<li>\u8bf4\u660e\u7f51\u7edc\u5373\u5c06\u62e5\u585e<\/li>\n<\/ul>\n<p>\u53d1\u9001\u65b9\u7ef4\u62a4\u53d8\u91cfCongWin: \u5df2\u53d1\u9001\u4f46\u662f\u672a\u786e\u8ba4\u7684\u6570\u636e\u91cf(Byte), \u6709: LastByteSent &#8211; LastByteAcked &lt;= CongWin<\/p>\n<p>\u4ee4 rate = CongWin \/ RTT, \u5355\u4f4d byte\/sec, \u5373\u5f53\u524d\u6bcf\u79d2\u949f\u5411\u7f51\u7edc\u6ce8\u5165\u7684\u6700\u5927\u901f\u7387<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220202724672.png\" alt=\"image-20241220202724672\" style=\"zoom:50%;\" \/><\/p>\n<h3>\u53d1\u9001\u901f\u7387\u63a7\u5236\u7b97\u6cd5<\/h3>\n<p>CongWin\u662f\u52a8\u6001\u7684, \u611f\u77e5\u7f51\u7edc\u62e5\u585e\u7a0b\u5ea6\u7684\u51fd\u6570<\/p>\n<ul>\n<li>\u8d85\u65f6: CongWin = MSS, \u8fdb\u5165SS\u9636\u6bb5, \u7136\u540e\u6bcf\u4e2aRTT\u500d\u589e\u76f4\u5230CongWin \/ 2, \u4ece\u800c\u8fdb\u5165CA\u9636\u6bb5<\/li>\n<li>3\u4e2a\u91cd\u590dACK: CongWin = CongWin \/ 2, CA\u9636\u6bb5<\/li>\n<li>\u9664\u4e0a\u8ff0\u5916, \u8bf4\u660e\u7f51\u7edc\u826f\u597d, CongWin\u53ef\u4ee5\u589e\u52a0\n<ul>\n<li>SS, \u6162\u542f\u52a8\u9636\u6bb5: \u5feb\u901f\u500d\u589e<\/li>\n<li>CA, \u62e5\u585e\u907f\u514d\u9636\u6bb5: \u6162\u901f\u7ebf\u6027<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<blockquote>\n<p>\u590d\u4e60: MSS, Maximum Segment Size, TCP\u6700\u5927\u62a5\u6587\u6bb5\u5927\u5c0f<br \/>\n\u5728\u4e0a\u9762\u4ee4cwnd = MSS, \u5b9e\u9645\u4e0a\u5c31\u662f\u8c03\u6574\u7a97\u53e3\u4e3a\u4e00\u4e2a\u62a5\u6587\u6bb5\u7684\u957f\u5ea6\u4e86<\/p>\n<p>\u540d\u6b21\u89e3\u91ca:<br \/>\nSS, Slow-Start, \u6162\u542f\u52a8<br \/>\nCA, Congestion-Avoidance, \u62e5\u585e\u907f\u514d<\/p>\n<\/blockquote>\n<h3>\u8054\u5408\u63a7\u5236\u65b9\u6cd5<\/h3>\n<p>TCP\u53d1\u9001\u7aef\u9700\u8981\u63a7\u5236\u53d1\u9001\u7a97\u53e3, \u5373, \u53d1\u9001\u4f46\u662f\u672a\u786e\u8ba4\u7684\u6570\u636e\u91cf\u540c\u65f6\u6ee1\u8db3\u6d41\u91cf\u63a7\u5236, \u62e5\u585e\u63a7\u5236\u7684\u8981\u6c42<\/p>\n<p>SendWin = min{CongWin, RecvWin}, \u5176\u4e2d<\/p>\n<ul>\n<li>CongWin\u662f\u672c\u5730\u52a8\u6001\u6d4b\u7b97\u7684<\/li>\n<li>RecvWin\u662f\u634e\u5e26\u6280\u672f\u4e2d, \u63a5\u6536\u65b9ACK\u4fe1\u606f\u643a\u5e26\u7684<\/li>\n<\/ul>\n<blockquote>\n<p>\u6bd4\u5982, \u5f53\u524dcwnd = 4000B, \u63a5\u6536\u65b9rwnd = 1024B, \u5219\u53d1\u9001\u65b9\u8981\u63a7\u5236\u53d1\u9001\u901f\u7387, \u6bcf\u5355\u4f4d\u65f6\u95f4\u6700\u591a\u6ce8\u5165min{cwnd, rwnd}\u7684\u6570\u636e, \u53731024B<\/p>\n<\/blockquote>\n<h3>\u62e5\u585e\u63a7\u5236\u7b56\u7565: \u6162\u542f\u52a8<\/h3>\n<p>TCP\u521a\u521a\u5efa\u7acb\u65f6, cwnd = MSS<\/p>\n<blockquote>\n<p>\u6bd4\u5982, \u521a\u521a\u5efa\u7acb\u8fde\u63a5, cwnd = MSS = 1450B&amp; RTT = 200ms<br \/>\n\u5219\u521d\u59cb\u901f\u7387 = 58.4kbps<\/p>\n<\/blockquote>\n<p>\u6b64\u65f6\u7684\u53ef\u7528\u5e26\u5bbd\u53ef\u80fd\u5f88\u5927, \u6bcf\u4e2aRTT\u90fd\u7ffb\u500dcwnd, \u76f4\u5230\u53d1\u751f\u4e22\u5931\u6216\u8005\u91cd\u590dACK\u4e8b\u4ef6<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220214809925.png\" alt=\"image-20241220214809925\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220215225693.png\" alt=\"image-20241220215225693\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u4e00\u4e2a\u4f8b\u5b50:<br \/>\ncwnd = 1, 2, 4, 8, 16, 32[\u4e22\u5931, \u91cd\u5236, \u8bbe\u7f6e\u8b66\u6212\u503c16, \u8fdb\u5165SS]<br \/>\ncwnd = 1, 2, 4, 8, 16, <strong>17, 18, 19, 20, 21, 22<\/strong>[\u4e22\u5931, \u8bbe\u7f6e\u8b66\u6212\u503c11SS]<br \/>\ncwnd = 1, 2, 4, 8, <strong>11, 12, 13, 14<\/strong>[3\u4e2a\u5197\u4f59ack, \u4ece\u8b66\u6212\u503c7\u5f00\u59cb, \u76f4\u63a5\u8fdb\u5165CA]<br \/>\ncwnd = <strong>7, 8, 9, &#8230;<\/strong><\/p>\n<\/blockquote>\n<p>\u5373, \u4e22\u5931(\u4e25\u91cd\u62e5\u585e)\u4e0e\u5197\u4f59ACK(\u8f7b\u5fae\u62e5\u585e)\u7684\u63a7\u5236\u7b56\u7565\u6709\u533a\u522b<\/p>\n<p>\u6162\u542f\u52a8\u5176\u5b9e\u5e76\u4e0d\u6162, SS\u7684\u8fed\u4ee3\u53ea\u9700\u51e0\u6b21\u5c31\u53ef\u4ee5\u89e6\u78b0\u5230\u7ebf\u8def\u6027\u80fd\u74f6\u9888<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220220429024.png\" alt=\"image-20241220220429024\" style=\"zoom:33%;\" \/><\/p>\n<h3>TCP\u7684\u516c\u5e73\u6027<\/h3>\n<p>\u5728\u4e24\u4e2a\u4e3b\u673a\u7ade\u4e89\u74f6\u9888\u5e26\u5bbd\u8d44\u6e90\u7684\u65f6\u5019, \u6bcf\u4e2a\u4e3b\u673a\u80fd\u83b7\u5f97 1\/n \u7684\u5e26\u5bbd<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220220553318.png\" alt=\"image-20241220220553318\" style=\"zoom:33%;\" \/><\/p>\n<h1>Chap4. \u7f51\u7edc\u5c42: \u6570\u636e\u5e73\u9762<\/h1>\n<p>\u4ece\u7b2c\u56db\u7ae0\u5f00\u59cb, \u79bb\u5f00\u7f51\u7edc\u8fb9\u7f18, \u8fdb\u5165\u7f51\u7edc\u6838\u5fc3\u7684\u90e8\u5206<\/p>\n<h2>4.1 \u5bfc\u8bba<\/h2>\n<h3>\u7f51\u7edc\u5c42\u670d\u52a1<\/h3>\n<p>\u7f51\u7edc\u5c42\u5728\u53d1\u9001\u4e3b\u673a\u548c\u63a5\u6536\u4e3b\u673a\u5bf9\u4e4b\u95f4\u4f20\u9001\u6bb5(segment)<\/p>\n<ul>\n<li>\u5728\u53d1\u9001\u7aef, \u5c06\u6bb5\u5c01\u88c5\u5230\u6570\u636e\u62a5\u4e2d<\/li>\n<li>\u5728\u63a5\u6536\u6bb5, \u5c06\u6bb5\u4e0a\u4ea4\u7ed9\u4f20\u8f93\u5c42\u5b9e\u4f53<\/li>\n<\/ul>\n<p>\u7f51\u7edc\u5c42\u534f\u8bae\u5b58\u5728\u4e8e\u6bcf\u4e00\u4e2a\u4e3b\u673a\u548c\u8def\u7531\u5668<\/p>\n<p>\u4e0e\u4f20\u8f93\u5c42\u7684\u7aef\u5230\u7aef\u670d\u52a1\u6bd4\u8f83<\/p>\n<ul>\n<li>\u4f20\u8f93\u5c42: \u4e24\u4e2a\u8fdb\u7a0b\u4e4b\u95f4, \u4e00\u822c\u53ea\u4f53\u73b0\u5728\u7aef\u7cfb\u7edf\u4e0a(TCP\u8fde\u63a5)<\/li>\n<li>\u7f51\u7edc\u5c42: \u4e24\u4e2a\u4e3b\u673a\u4e4b\u95f4, \u6d89\u53ca\u5230\u8def\u5f84\u4e0a\u7684\u8def\u7531\u5668<\/li>\n<\/ul>\n<h3>\u7f51\u7edc\u5c42\u5173\u952e\u529f\u80fd<\/h3>\n<ul>\n<li>\u8f6c\u53d1: \u5c40\u90e8\u529f\u80fd, \u8def\u7531\u5668\u5c06\u6536\u5230\u7684\u5206\u7ec4\u89e3\u5c01\u88c5, \u5206\u6790, \u518d\u5c01\u88c5, \u4ece\u6307\u5b9a\u63a5\u53e3\u53d1\u51fa, \u9001\u5230\u7279\u5b9a\u7684\u7f51\u7edc<\/li>\n<li>\u8def\u7531: \u5168\u5c40\u7b97\u6cd5, \u51b3\u5b9a\u5206\u7ec4\u4ece\u53d1\u9001\u4e3b\u673a\u5230\u76ee\u6807\u63a5\u6536\u4e3b\u673a\u5230\u8def\u5f84<\/li>\n<\/ul>\n<blockquote>\n<p>\u53ef\u4ee5\u7528\u65c5\u884c\u7c7b\u6bd4: \u8f6c\u53d1\u662f\u5355\u4e2a\u5c94\u8def\u7684\u9009\u62e9, \u800c\u8def\u7531\u662f\u5168\u5c40\u7684\u8def\u7ebf\u89c4\u5212<\/p>\n<\/blockquote>\n<h3>\u6570\u636e\u5e73\u9762\u4e0e\u63a7\u5236\u5e73\u9762<\/h3>\n<p>\u6570\u636e\u5e73\u9762:<\/p>\n<p>\u5728\u672c\u5730, \u6bcf\u4e2a\u8def\u7531\u5668\u7684\u529f\u80fd, \u51b3\u5b9a\u4ece\u8def\u7531\u5668\u7684\u8f93\u5165\u7aef\u53e3\u5230\u8fbe\u7684\u5206\u7ec4\u5982\u4f55\u8f6c\u53d1\u5230\u8f93\u51fa\u7aef\u53e3<\/p>\n<ul>\n<li>\u4f20\u7edf\u65b9\u5f0f: \u76ee\u6807\u5730\u5740+\u8f6c\u53d1\u8868<\/li>\n<li>SDN\u65b9\u5f0f: \u591a\u4e2a\u5b57\u6bb5+\u6d41\u8868<\/li>\n<\/ul>\n<p>\u63a7\u5236\u5e73\u9762:<\/p>\n<p>\u7f51\u7edc\u8303\u56f4\u5185\u7684\u903b\u8f91, \u51b3\u5b9a\u6570\u636e\u62a5\u5982\u4f55\u5728\u8def\u7531\u5668\u95f4\u8def\u7531, \u6570\u636e\u62a5\u4ece\u6e90\u5230\u76ee\u6807\u4e3b\u673a\u7684\u7aef\u5230\u7aef\u8def\u5f84<\/p>\n<ul>\n<li>\u4f20\u7edf\u8def\u7531\u7b97\u6cd5: \u8def\u7531\u5668\u4e2d\u5b9e\u73b0<\/li>\n<li>SDN: \u8fdc\u7a0b\u670d\u52a1\u5668\u5b9e\u73b0<\/li>\n<\/ul>\n<blockquote>\n<p>\u540d\u6b21\u89e3\u91ca: SDN, Software Defined Network, \u8f6f\u4ef6\u5b9a\u4e49\u7f51\u7edc, \u4e00\u79cd\u53ef\u7f16\u7a0b\u7684\u7f51\u7edc\u5b9e\u73b0<\/p>\n<\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220232229467.png\" alt=\"image-20241220232229467\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u4f20\u7edf\u65b9\u5f0f\u4e2d, \u63a7\u5236\u5e73\u9762\u4e0e\u6570\u636e\u5e73\u9762\u7d27\u8026\u5408, \u5b9e\u73b0\u5728\u6bcf\u4e2a\u5177\u4f53\u7684\u8def\u7531\u5668\u4e2d, \u662f\u5206\u5e03\u5f0f\u7684<\/p>\n<ul>\n<li>\u8def\u7531\u5668\u7b97\u51fa\u8def\u7531\u8868(\u63a7\u5236\u5e73\u9762), \u7136\u540e\u5206\u7ec4\u6839\u636e\u8def\u7531\u8868\u7684\u89c4\u5219\u8f6c\u53d1(\u6570\u636e\u5e73\u9762)<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220232534526.png\" alt=\"image-20241220232534526\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728SDN\u4e2d, \u8fdc\u7aef\u670d\u52a1\u5668\u8fd0\u884c\u7740\u7f51\u7edc\u64cd\u4f5c\u7cfb\u7edf, \u901a\u8fc7\u5357\u5411\u63a5\u53e3\u5c06\u6d41\u8868\u4ea4\u4ed8\u8def\u7531\u5668(\u63a7\u5236\u5e73\u9762), \u8def\u7531\u5668\u6839\u636e\u6d41\u8868\u5bf9\u5206\u7ec4\u8fdb\u884c\u591a\u4e2a\u5b57\u6bb5\u7684\u5339\u914d\u8f6c\u53d1<\/p>\n<ul>\n<li>\u8fdc\u7aef\u670d\u52a1\u5668\u53ef\u4ee5\u7f16\u7a0b, \u6d41\u8868\u7684\u7b97\u6cd5\u5f88\u7075\u6d3b, \u5177\u5907\u5f39\u6027, \u662f\u96c6\u4e2d\u5f0f\u7684<\/li>\n<\/ul>\n<blockquote>\n<p>\u591a\u4e2a\u5b57\u6bb5\u53ef\u80fd\u6709: \u6e90MAC, \u76ee\u6807MAC, \u6e90IP, \u76ee\u6807IP, \u6e90Port, \u76ee\u6807Port, \u7b49\u7b49<br \/>\n\u5339\u914d\u591a\u4e2a\u5b57\u6bb5\u540e, \u53ef\u4ee5\u9009\u62e9\u51fa\u5408\u9002\u7684\u52a8\u4f5c: \u8f6c\u53d1, \u963b\u585e, \u6cdb\u6d2a, \u4fee\u6539, \u7b49\u7b49<\/p>\n<\/blockquote>\n<h3>\u7f51\u7edc\u5c42\u670d\u52a1\u6a21\u578b<\/h3>\n<p>\u6709\u5e26\u5bbd, \u4e22\u5931, \u4fdd\u5e8f, \u5ef6\u8fdf, \u62e5\u585e\u53cd\u9988\u7b49\u6307\u6807\u53ef\u4ee5\u8861\u91cf\u4e00\u4e2a\u7f51\u7edc\u7684\u670d\u52a1\u8d28\u91cf. \u4e00\u79cd\u7f51\u7edc\u6a21\u578b\u5bf9\u5e94\u4e86\u4e00\u7ec4\u6307\u6807<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241220233558134.png\" alt=\"image-20241220233558134\" style=\"zoom:33%;\" \/><\/p>\n<h2>4.2 \u8def\u7531\u5668\u7ec4\u6210<\/h2>\n<h3>\u8def\u7531\u5668\u7ed3\u6784\u6982\u51b5<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221133533278.png\" alt=\"image-20241221133533278\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u867d\u7136\u5728\u6a21\u578b\u4e2d\u8ba8\u8bba\u4e86\u8def\u7531\u5668\u7684\u8f93\u5165, \u8f93\u51fa\u7aef\u53e3, \u4f46\u662f\u5728\u5b9e\u9645\u60c5\u51b5\u4e2d, \u8def\u7531\u5668\u7684\u7aef\u53e3\u662f\u53cc\u5411\u7ed1\u5b9a\u7684: \u5373\u662f\u8f93\u5165, \u4e5f\u662f\u8f93\u51fa<\/p>\n<\/blockquote>\n<h3>\u8f93\u5165\u7aef\u53e3\u529f\u80fd<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221134619091.png\" alt=\"image-20241221134619091\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u56fe\u4e2d\u7684switch fabric\u662f\u4ea4\u6362\u8bbe\u5907\u4e2d\u7528\u4e8e\u8fde\u63a5\u8f93\u5165\u7aef\u53e3\u548c\u8f93\u51fa\u7aef\u53e3\u7684\u6570\u636e\u4f20\u8f93\u7ed3\u6784<\/p>\n<\/blockquote>\n<h3>\u7aef\u53e3\u7f13\u5b58<\/h3>\n<p>\u8def\u7531\u5668\u7684\u8f93\u5165, \u8f93\u51fa\u7aef\u53e3\u90fd\u6709\u7f13\u5b58\u961f\u5217, \u7528\u6765\u5339\u914d\u77ac\u65f6\u8f93\u5165\u8f93\u51fa\u901f\u5ea6\u7684\u4e0d\u4e00\u81f4\u6027<\/p>\n<p>\u5934\u90e8\u963b\u585e(HOL, Head-Of-Line), \u6392\u5728\u961f\u4f0d\u5934\u7684\u6570\u636e\u62a5\u963b\u585e, \u59a8\u788d\u4e86\u540e\u9762\u6570\u636e\u62a5\u7684\u524d\u8fdb<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221135345285.png\" alt=\"image-20241221135345285\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u4ea4\u6362\u7ed3\u6784: Fabric<\/h3>\n<p>\u5c06\u5206\u7ec4\u4ece\u8f93\u5165\u7f13\u51b2\u533a\u4f20\u8f93\u5230\u5408\u9002\u7684\u8f93\u51fa\u7aef\u53e3, \u8fd9\u4e2a\u5c40\u90e8\u673a\u6784\u7684\u4ea4\u6362\u901f\u7387\u5e94\u8be5 &gt;= n\u500d\u7aef\u53e3\u5de5\u4f5c\u901f\u7387, Fabric\u4e00\u822c\u4e0d\u6210\u4e3a\u74f6\u9888<\/p>\n<p>Fabric\u7684\u4e3b\u8981\u5de5\u4f5c\u65b9\u5f0f\u67093\u79cd:<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221135820544.png\" alt=\"image-20241221135820544\" style=\"zoom:33%;\" \/><\/p>\n<h3>Fabric: \u901a\u8fc7\u5185\u5b58\u4ea4\u6362(memory)<\/h3>\n<p>\u7b2c\u4e00\u4ee3\u8def\u7531\u5668<\/p>\n<p>\u8def\u7531\u5668\u662f\u4f20\u7edf\u8ba1\u7b97\u673a, \u901a\u7528CPU\u7684\u76f4\u63a5\u63a7\u5236, \u5728\u8f6f\u4ef6\u5c42\u9762\u5b9e\u73b0\u8def\u7531, \u5728\u786c\u4ef6\u4e0a\u5b9e\u9645\u4e0a\u8d70\u4e86\u7cfb\u7edf\u603b\u7ebf(\u901a\u7528\u8ba1\u7b97\u673a\u7684\u603b\u7ebf)<\/p>\n<ul>\n<li>\u5206\u7ec4\u62f7\u8d1d\u5230\u7cfb\u7edf\u5185\u5b58<\/li>\n<li>CPU\u4ece\u5206\u7ec4\u5934\u90e8\u63d0\u53d6\u76ee\u6807\u5730\u5740, \u67e5\u8def\u7531\u8868<\/li>\n<li>CPU\u5b9a\u4f4d\u76ee\u6807\u7aef\u53e3, \u62f7\u8d1d\u8f93\u51fa<\/li>\n<li>\u8f6c\u53d1\u901f\u7387\u88ab\u5185\u5b58\u5e26\u5bbd\u9650\u5236(\u6570\u636e\u62a5\u901a\u8fc7\u7cfb\u7edf\u603b\u7ebf\u4e24\u6b21)<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221140444741.png\" alt=\"image-20241221140444741\" style=\"zoom:33%;\" \/><\/p>\n<h3>Fabric: \u901a\u8fc7\u603b\u7ebf\u4ea4\u6362(bus)<\/h3>\n<ul>\n<li>\u6570\u636e\u62a5\u901a\u8fc7\u5171\u4eab\u603b\u7ebf, \u603b\u7ebf\u8d44\u6e90\u5b58\u5728\u7ade\u4e89(\u63a5\u53e3\u4e4b\u95f4)<\/li>\n<li>\u8fd9\u91cc\u7684\u603b\u7ebf\u4e13\u7528\u4e8e\u6570\u636e\u62a5, \u662f\u786c\u4ef6\u5c42\u9762\u5f00\u53d1\u7684\u901a\u9053<\/li>\n<\/ul>\n<p>\u8fd9\u79cd\u8def\u7531\u5668\u5bf9\u4e8e\u63a5\u5165\u6216\u4f01\u4e1a\u7ea7\u9700\u6c42\u901f\u5ea6\u5df2\u7ecf\u8db3\u591f, \u4f46\u4e0d\u9002\u5408\u533a\u57df\u6216\u8005\u9aa8\u5e72\u7ea7\u7f51\u7edc<\/p>\n<h3>Fabric: \u901a\u8fc7\u4ea4\u53c9\u5f00\u5173\u4ea4\u6362(\u4e92\u8054\u7f51\u7edc, crossbar)<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221143342931.png\" alt=\"image-20241221143342931\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u8f93\u51fa\u7aef\u53e3\u7f13\u5b58<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221150214230.png\" alt=\"image-20241221150214230\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u7f13\u5b58\u8c03\u5ea6\u7b56\u7565<\/h3>\n<p>\u8fd8\u53ef\u4ee5\u7ec6\u5206\u4e3a\u5904\u7406\u7b56\u7565\u548c\u4e22\u5f03\u7b56\u7565<\/p>\n<ul>\n<li>FIFO\u7b56\u7565<\/li>\n<li>\u4f18\u5148\u7ea7\u7b56\u7565<\/li>\n<li>RR\u7b56\u7565(\u6bcf\u4e00\u7c7b\u8f6e\u8f6c\u53d1\u9001)<\/li>\n<li>&#8230;<\/li>\n<\/ul>\n<h2>4.3 IP\u534f\u8bae<\/h2>\n<h3>\u4e92\u8054\u7f51\u7684\u7f51\u7edc\u5c42<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221154956061.png\" alt=\"image-20241221154956061\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>\u8def\u7531\u534f\u8bae(RIP, OSPF, BGP\u7b49)\u662f\u63a7\u5236\u5e73\u9762\u7684\u4efb\u52a1<\/li>\n<li>IP\u534f\u8bae\u662f\u6570\u636e\u5e73\u9762\u7684<\/li>\n<\/ul>\n<h3>IPv4\u6570\u636e\u5305\u683c\u5f0f<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221160238067.png\" alt=\"image-20241221160238067\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>\u9898\u5916\u8bdd, \u5c3d\u7ba1IP\u534f\u8bae\u89c4\u5b9a\u4e86\u8def\u7531\u5668\u5728TTL=0\u65f6\u53ef\u4ee5\u56de\u590d\u4e00\u4e2aICMP\u4fe1\u606f, \u544a\u77e5\u8d85\u65f6\u4e22\u5f03, \u4f46\u662f\u5f88\u591a\u8def\u7531\u5668, \u9632\u706b\u5899\u89c4\u5219\u88ab\u8bbe\u7f6e\u6210\u4e86\u9759\u9ed8<\/p>\n<p>\u53e6\u5916, \u7531\u4e8e\u7f51\u7edc\u62e5\u585e\u4e22\u5f03\u7684\u62a5\u6587, \u4e00\u822c\u4e0d\u4f1a\u56de\u590d\u4fe1\u606f<\/p>\n<\/blockquote>\n<h3>IP\u5206\u7247\u548c\u91cd\u7ec4<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221161920946.png\" alt=\"image-20241221161920946\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221162039436.png\" alt=\"image-20241221162039436\" style=\"zoom:33%;\" \/><\/p>\n<p>length, ID, fragflag: \u6807\u8bc6\u4f4d: \u540e\u9762\u8fd8\u6709\u6ca1\u6709<\/p>\n<p>\u975e\u5e38\u91cd\u8981: \u8ba1\u7b97offset\u7684\u65f6\u5019, \u4ee58\u5b57\u8282\u4e3a\u5355\u4f4d<\/p>\n<p>\u5206\u7247\u4e4b\u540e, \u7531\u76ee\u6807\u4e3b\u673a\u8d1f\u8d23\u91cd\u7ec4. \u5982\u679c\u5206\u7247\u4e2d\u6709\u8d85\u65f6, \u5219\u4e0d\u5f97\u4e0d\u4e22\u5f03\u6574\u7ec4<\/p>\n<h3>IP\u7f16\u5740: \u5f15\u8bba<\/h3>\n<p>IP\u5730\u5740\u6807\u8bc6\u7684\u662f\u63a5\u5165\u7f51\u7edc\u7684\u63a5\u53e3: \u4e3b\u673a\/\u8def\u7531\u5668\u548c\u7269\u7406\u94fe\u8def\u7684\u8fde\u63a5\u5904<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221162801105.png\" alt=\"image-20241221162801105\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u5b50\u7f51(Subnets)<\/h3>\n<ul>\n<li>\u5b50\u7f51\u7684IP\u524d\u7f00\u662f\u4e00\u6837\u7684<\/li>\n<li>\u5b50\u7f51\u5185\u901a\u8baf\u4e0d\u9700\u8981\u8def\u7531, \u4e5f\u8bb8\u4f1a\u901a\u8fc7\u4ea4\u6362\u673a<\/li>\n<\/ul>\n<blockquote>\n<p>\u4eceIP\u534f\u8bae\u7684\u89d2\u5ea6\u6765\u770b, \u5b50\u7f51\u5185\u901a\u8baf&quot;\u4e00\u8df3\u53ef\u8fbe&quot;<\/p>\n<\/blockquote>\n<p>\u8981\u5224\u65ad\u4e00\u4e2a\u5b50\u7f51, \u53ea\u9700\u8981\u65ad\u5f00\u7f51\u7edc\u63a5\u53e3, \u5f62\u6210\u7684\u7f51\u7edc\u5b64\u5c9b\u5c31\u662f\u5b50\u7f51<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221234549225.png\" alt=\"image-20241221234549225\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>ABC\u662f\u5355\u64ad\u5730\u5740<\/li>\n<li>D\u662f\u7ec4\u64ad\u5730\u5740, \u53d1\u7ed9\u4e00\u4e2a\u5730\u5740\u4f1a\u901a\u8fc7\u7279\u5b9a\u534f\u8bae\u53d1\u9001\u7ed9\u7ec4\u5185\u4e3b\u673a<\/li>\n<\/ul>\n<p>\u4e92\u8054\u7f51\u7684\u8def\u7531\u662f\u4ee5\u5b50\u7f51\u4e3a\u5355\u4f4d\u7684: \u65e0\u6cd5\u7ef4\u62a42^32\u8fd9\u4e48\u591a\u7684\u8def\u7531\u4fe1\u606f<\/p>\n<p>\u5728\u8def\u7531\u8868\u4e2d, \u6bcf\u4e00\u4e2a\u7f51\u7edc\u662f\u4e00\u4e2a\u8868\u9879<\/p>\n<h3>\u7279\u6b8aIP\u5730\u5740\u7ea6\u5b9a<\/h3>\n<ul>\n<li>\u5b50\u7f51\u90e8\u5206\u51680: \u672c\u7f51\u7edc<\/li>\n<li>\u4e3b\u673a\u90e8\u5206\u51680: \u672c\u4e3b\u673a<\/li>\n<li>\u4e3b\u673a\u90e8\u5206\u51681: \u5e7f\u64ad\u5168\u7f51<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241221235415661.png\" alt=\"image-20241221235415661\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u5185\u7f51\u4e13\u7528\u5730\u5740<\/h3>\n<p>\u4e13\u7528\u4e8e\u5185\u7f51\u7684\u5730\u5740, \u6c38\u8fdc\u4e0d\u4f1a\u5f53\u4f5c\u516c\u7528\u5730\u5740\u5206\u914d<\/p>\n<ul>\n<li>\u516c\u7f51\u5185\u4e0d\u4f1a\u51fa\u73b0\u5185\u7f51\u5730\u5740<\/li>\n<li>\u5185\u7f51\u4e2d\u4e0d\u4f1a\u51fa\u73b0\u516c\u7f51\u5730\u5740<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222002343807.png\" alt=\"image-20241222002343807\" style=\"zoom:33%;\" \/><\/p>\n<p>\u8def\u7531\u5668\u4e0d\u5bf9\u76ee\u6807\u5730\u5740\u662f\u5185\u7f51\u5730\u5740\u7684\u5206\u7ec4\u8fdb\u884c\u8f6c\u53d1<\/p>\n<h3>CIDR: \u65e0\u7c7b\u57df\u95f4\u8def\u7531<\/h3>\n<p>\u5b50\u7f51\u90e8\u5206\u53ef\u4ee5\u5728\u4efb\u610f\u7684\u4f4d\u7f6e, \u683c\u5f0fa.b.c.d\/x, x\u662f\u5730\u5740\u4e2d\u5b50\u7f51\u53f7\u7684\u957f\u5ea6<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222002514270.png\" alt=\"image-20241222002514270\" style=\"zoom:33%;\" \/><\/p>\n<p>ABC\u7c7b\u5730\u5740\u662f\u4e92\u8054\u7f51\u521d\u671f\u7684\u4ea7\u7269, \u968f\u7740\u9700\u6c42\u589e\u591a\u663e\u5f97\u4e0d\u591f\u7075\u6d3b, CIDR\u6280\u672f\u6210\u4e3a\u4e3b\u6d41<\/p>\n<p>\u5404\u4e2a\u5b50\u7f51\u6bb5\u7684\u63a9\u7801\u5b58\u50a8\u5728\u8def\u7531\u5668\u7684\u8def\u7531\u8868\u4e2d, \u8def\u7531\u8868\u662f\u901a\u8fc7\u8def\u7531\u5668\u534f\u8bae\u5b66\u4e60\u5230\u7684<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222003235114.png\" alt=\"image-20241222003235114\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222003301635.png\" alt=\"image-20241222003301635\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>\u9ed8\u8ba4\u7aef\u53e3\u4e00\u822c\u4ee3\u8868\u8def\u7531\u5668\u7684\u51fa\u53e3IP(\u9ed8\u8ba4\u7f51\u5173)<\/li>\n<\/ul>\n<blockquote>\n<p>\u7f51\u5173: \u5185\u7f51\u7684\u51fa\u53e3, \u4f4d\u4e8e\u591a\u4e2a\u7f51\u7edc\u4e4b\u95f4, \u534f\u8c03\u7f51\u7edc\u7684\u6570\u636e<\/p>\n<\/blockquote>\n<h3>\u83b7\u5f97IP\u5730\u5740<\/h3>\n<ul>\n<li>\u7f51\u7edc\u7ba1\u7406\u5458\u5206\u914d, \u672c\u5730\u624b\u52a8\u586b\u5199<\/li>\n<li>DHCP\u6280\u672f, \u4ece\u670d\u52a1\u5668\u83b7\u53d6<\/li>\n<\/ul>\n<p>DHCP: \u5141\u8bb8\u4e3b\u673a\u5728\u52a0\u5165\u7f51\u7edc\u7684\u65f6\u5019, \u52a8\u6001\u7684\u4ece\u670d\u52a1\u5668\u83b7\u5f97IP\u5730\u5740<\/p>\n<ul>\n<li>\u5b9a\u65f6\u79df\u7528<\/li>\n<li>\u5230\u671f\u5237\u65b0<\/li>\n<\/ul>\n<p>DHCP\u539f\u7406:<\/p>\n<ol>\n<li>\u4e3b\u673a\u4e0a\u7ebf\u5e7f\u64adDHCP discover (32\u4f4d\u51681)<\/li>\n<li>DHCP\u670d\u52a1\u5668\u56de\u590dDHCP offer<\/li>\n<li>\u4e3b\u673a\u8bf7\u6c42IP, DHCP\u670d\u52a1\u5668\u53d1\u9001IP\u4e0e\u76f8\u5173\u4fe1\u606f<\/li>\n<li>\u4e00\u6bb5\u65f6\u95f4\u540e, IP\u8fc7\u671f, \u4e3b\u673arenew<\/li>\n<\/ol>\n<p>DHCP\u4e0d\u4ec5\u63d0\u4f9bIP\u5730\u5740, \u8fd8\u4f1a\u63d0\u4f9b: \u9ed8\u8ba4\u7f51\u5173\u5730\u5740, \u9ed8\u8ba4DNS\u57df\u540d\u4e0e\u5730\u5740, \u5b50\u7f51\u63a9\u7801<\/p>\n<p>\u4f5c\u4e3a\u673a\u6784, \u53ef\u4ee5\u5411ICANN\u63d0\u4ea4\u624b\u7eed, \u7533\u8bf7IP\u5730\u5740\u5757<\/p>\n<h3>\u5c42\u6b21\u7f16\u5740: \u8def\u7531\u805a\u96c6<\/h3>\n<p>\u901a\u5e38\u7528CIDR\u8868\u793a\u6cd5: \u805a\u96c6-\u901a\u544a-\u805a\u96c6-\u901a\u544a<\/p>\n<p>\u5f53\u7136\u4e5f\u4f1a\u6709\u4e0d\u80fd\u76f4\u63a5\u805a\u96c6\u7684\u65f6\u5019, \u90a3\u53ea\u80fd\u76f4\u63a5\u901a\u544a<\/p>\n<p>\u8def\u7531\u805a\u96c6\u6280\u672f\u7528\u6765\u7b80\u5316\u8def\u7531\u5668\u4e2d\u5b58\u50a8\u7684\u8868\u9879, \u4ed6\u4e0d\u8d1f\u8d23\u4ea7\u751f\u89c4\u5219, \u53ea\u7528\u6765\u5316\u7b80, \u6240\u4ee5\u662f\u6570\u636e\u5e73\u9762\u7684\u529f\u80fd<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222124623021.png\" alt=\"image-20241222124623021\" style=\"zoom:33%;\" \/><\/p>\n<h3>\u5c42\u6b21\u7f16\u5740: \u7279\u6b8a\u8def\u7531\u4fe1\u606f<\/h3>\n<p>\u8def\u7531\u805a\u96c6\u6280\u672f\u5141\u8bb8\u8def\u7531\u5668\u9002\u5f53\u5938\u5927\u81ea\u5df1\u7684\u8def\u7531\u8303\u56f4(\u6709\u7a7a\u6d1e\u7684, \u5927\u6982\u96c6\u7684\u805a\u96c6), \u6bd4\u5982\u67d0\u4e2a\u5b50\u7f51A\u67098\u6bb5\u5730\u5740, \u4e00\u4e2a\u8def\u7531\u5668\u53ea\u8d1f\u8d237\u6bb5, \u4ed6\u4ecd\u53ef\u4ee5\u5ba3\u79f0\u81ea\u5df1\u8d1f\u8d23\u6574\u4e2aA\u7684\u8def\u7531,  \u800c\u7f3a\u5931\u7684\u4e00\u6bb5\u7684\u8def\u7531\u4fe1\u606f\u56e0\u4e3a\u66f4\u7cbe\u786e, \u9075\u5faa\u6700\u957f\u5339\u914d\u539f\u5219, \u4ecd\u7136\u4f1a\u5728\u4e0a\u7ea7\u8def\u7531\u4e2d\u53d1\u9001\u7ed9\u6b63\u786e\u7684\u8def\u7531\u5668<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222130232484.png\" alt=\"image-20241222130232484\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u5938\u5927\u7684\u8fc7\u7a0b\u4e2d, \u5e94\u8be5\u5c3d\u53ef\u80fd\u5c11\u5938\u5927, \u9632\u6b62\u9020\u6210\u8def\u7531\u9ed1\u6d1e, \u5438\u5f15\u5927\u91cf\u5904\u7406\u4e0d\u4e86\u7684\u4fe1\u606f. \u540c\u65f6, \u5e94\u8be5\u914d\u7f6e\u4e22\u5f03\u5904\u7406\u4e0d\u4e86\u7684\u6570\u636e\u5305, \u9632\u6b62\u5728\u7f51\u7edc\u4e2d\u56de\u73af, \u9020\u6210\u66f4\u591a\u95ee\u9898<\/p>\n<h3>NAT: Network Addr Translation<\/h3>\n<p>\u7531\u4e8eIP\u5730\u5740\u532e\u4e4f, \u6216\u8005\u5b89\u5168\u8003\u8651, \u591a\u4e2a\u5185\u7f51\u8bbe\u5907\u5171\u4eab\u4e00\u4e2a\u51fa\u53e3\u516c\u7f51IP<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222140350859.png\" alt=\"image-20241222140350859\" style=\"zoom:33%;\" \/><\/p>\n<p>\u652f\u6301NAT\u7684\u8def\u7531\u5668<\/p>\n<ul>\n<li>\u5916\u51fa\u6570\u636e\u5305: \u66ff\u6362\u6e90IP, \u6e90\u7aef\u53e3\u53f7\u4e3a\u81ea\u5df1\u7684IP\u548c\u7aef\u53e3\u53f7Port<\/li>\n<li>\u5728NAT\u8f6c\u6362\u8868\u4e2d, \u8bb0\u5f55\u8f6c\u6362\u4fe1\u606f<\/li>\n<li>\u6536\u5230\u6570\u636e\u5305: \u68c0\u67e5\u7aef\u53e3\u53f7, \u67e5\u8868\u8f6c\u53d1\u5185\u7f51<\/li>\n<\/ul>\n<p>NAT\u6709\u4e00\u5b9a\u4e89\u8bae<\/p>\n<ul>\n<li>\u8def\u7531\u5668\u662f\u7b2c\u4e09\u5c42\u8bbe\u5907, \u4f46\u662f\u4fee\u6539\u4e86\u7b2c\u56db\u5c42\u7684\u4fe1\u606f(\u7aef\u53e3\u53f7)<\/li>\n<li>\u8fd9\u8fdd\u53cd\u7aef\u5230\u7aef\u539f\u5219: \u590d\u6742\u6027\u5e94\u8be5\u5411\u7f51\u7edc\u8fb9\u7f18\u8f6c\u79fb<\/li>\n<\/ul>\n<h3>IPv6<\/h3>\n<p>\u52a8\u673a<\/p>\n<ul>\n<li>32-bit\u5730\u5740\u7a7a\u95f4\u5df2\u7ecf\u88ab\u8017\u5c3d<\/li>\n<li>NAT\u8f6c\u53d1\u65f6, \u5934\u90e8\u7684checksum\u4e5f\u8981\u53d8, \u52a0\u91cd\u4e86\u8d1f\u62c5<\/li>\n<\/ul>\n<p>IPv6\u7279\u6027<\/p>\n<ul>\n<li>40\u5b57\u8282\u5934\u90e8\u56fa\u5b9a<\/li>\n<li>\u4e0d\u5141\u8bb8\u8def\u7531\u5668\u5206\u7247<\/li>\n<\/ul>\n<blockquote>\n<p>\u5982\u679c\u5206\u7ec4\u8fc7\u5927, \u8def\u7531\u5668\u76f4\u63a5\u4e22\u5f03, \u8fd4\u56de ICMPv6 too big, \u8ba9\u6e90\u4e3b\u673a\u81ea\u884c\u5904\u7406<\/p>\n<p>\u5728\u5b9e\u9645\u60c5\u51b5\u4e2d, v6\u901a\u8fc7\u8def\u5f84MTU\u53d1\u73b0(PTMTU)\u6765\u786e\u5b9a\u74f6\u9888\u8def\u5f84\u7684MTU, \u907f\u514d\u5206\u7247<\/p>\n<\/blockquote>\n<h3>IPv6 \u5934\u90e8<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222143441796.png\" alt=\"image-20241222143441796\" style=\"zoom:33%;\" \/><\/p>\n<p>\u548cv4\u5934\u90e8\u76f8\u6bd4\u4e3b\u8981\u7684\u53d8\u5316<\/p>\n<ul>\n<li>checksum\u88ab\u53bb\u6389, \u73b0\u5728\u4f9d\u8d56\u5176\u4ed6\u5c42\u7684\u68c0\u9a8c\n<ul>\n<li>TCP, UDP\u90fd\u6709\u81ea\u5df1\u7684checksum, \u8bb8\u591a\u94fe\u8def\u5c42\u534f\u8bae(\u5982CRC)\u4e5f\u6709\u81ea\u5df1\u7684checksum<\/li>\n<\/ul>\n<\/li>\n<li>options\u5141\u8bb8, \u4f46\u662f\u5728\u5934\u90e8\u4e4b\u5916\u7528next header\u5b57\u6bb5\u8868\u793a<\/li>\n<li>\u65b0\u589eICMPv6: \u65b0\u7684\u62a5\u6587\u7c7b\u578b, \u591a\u64ad\u7ec4\u7ba1\u7406\u529f\u80fd<\/li>\n<\/ul>\n<h3>v4 2 v6 \u5347\u7ea7<\/h3>\n<p>\u79ef\u91cd\u96be\u8fd4, \u6ca1\u6709flag day\u4e86<\/p>\n<p>v4 v6\u6df7\u5408\u65f6, \u7f51\u7edc\u5982\u4f55\u8fd0\u8f6c? \u96a7\u9053\u6280\u672f: v6\u7684\u5c9b\u5c7f\u95f4, \u901a\u8fc7v4\u96a7\u9053\u8fde\u63a5. \u968f\u7740v6\u7684\u90e8\u7f72\u8d8a\u6765\u8d8a\u5e7f, \u5c9b\u5c7f\u4f1a\u8d8a\u6765\u8d8a\u591a, \u76f4\u5230\u7edf\u4e00v6<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222144432608.png\" alt=\"image-20241222144432608\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222144451443.png\" alt=\"image-20241222144451443\" style=\"zoom:33%;\" \/><\/p>\n<p>ISP\u9700\u8981\u7ef4\u62a4\u53cc\u6808\u534f\u8bae, \u8fd9\u4f1a\u589e\u52a0\u4e00\u90e8\u5206\u5f00\u9500<\/p>\n<h2>4.4 \u901a\u7528\u8f6c\u53d1\u4e0eSDN<\/h2>\n<h3>\u6570\u91cf\u4f17\u591a, \u529f\u80fd\u5404\u5f02\u7684\u4e2d\u95f4\u76d2<\/h3>\n<p>\u8def\u7531\u5668\u5728\u7f51\u7edc\u5c42\u7684\u529f\u80fd<\/p>\n<ul>\n<li>IP\u8f6c\u53d1(\u6570\u636e\u5e73\u9762): \u5bf9\u4e8e\u5230\u6765\u7684\u5206\u7ec4\u5339\u914d\u8def\u7531\u8868\u89c4\u5219\u51b3\u5b9a\u5982\u4f55\u8f6c\u53d1<\/li>\n<li>\u8def\u7531\u7b97\u6cd5(\u63a7\u5236\u5e73\u9762): \u548c\u5176\u4ed6\u8def\u7531\u5668\u4ea4\u4e92, \u8ba1\u7b97\u8def\u7531\u8868<\/li>\n<\/ul>\n<p>\u5176\u4ed6\u79cd\u7c7b\u7e41\u591a\u7684\u7f51\u7edc\u8bbe\u5907(\u4e2d\u95f4\u76d2)<\/p>\n<ul>\n<li>\u4ea4\u6362\u673a, \u9632\u706b\u5899, NAT, IDS, \u8d1f\u8f7d\u5747\u8861\u670d\u52a1\u5668, &#8230;<\/li>\n<li>\u672a\u6765\u8fd8\u6709\u66f4\u591a\u7684\u90e8\u7f72<\/li>\n<\/ul>\n<p>\u8981\u6539\u53d8\u4e0a\u9762\u5206\u5e03\u5f0f\u7684\u8bbe\u5907\u7684\u5de5\u4f5c\u65b9\u5f0f, \u51e0\u4e4e\u4e0d\u53ef\u80fd<\/p>\n<p>\u8def\u7531\u5668\u90e8\u7f72\u91cf\u592a\u5927, \u89c4\u5219\u56fa\u5b9a, \u6ca1\u6cd5\u6539\u53d8<\/p>\n<h3>\u63a7\u5236\u5e73\u9762\u8bbe\u5907\u7279\u70b9<\/h3>\n<p>\u4e92\u8054\u7f51\u7f51\u7edc\u8bbe\u5907\u7ecf\u5e38\u5782\u76f4\u96c6\u6210<\/p>\n<ul>\n<li>\u8def\u7531\u5668, \u8def\u7531\u5668\u64cd\u4f5c\u7cfb\u7edf, \u5176\u4ed6\u786c\u4ef6\u5fc5\u987b\u6574\u4e2a\u5382\u5546\u914d\u5957<\/li>\n<li>\u5382\u5546\u5bf9\u6807\u51c6\u534f\u8bae(IP, RIP, BGP)\u7b49\u7684\u79c1\u6709\u5b9e\u73b0<\/li>\n<li>\u4e00\u6574\u5957\u4ea7\u54c1\u88ab\u7ed1\u67b6<\/li>\n<\/ul>\n<h3>SDN\u65b9\u5f0f, \u8f6f\u4ef6\u5b9a\u4e49\u7f51\u7edc<\/h3>\n<p>2005\u5e74\u4e4b\u540e, \u8003\u8651\u5230\u4e0a\u9762\u7684\u95ee\u9898, \u5f00\u59cb\u91cd\u65b0\u601d\u8003\u7f51\u7edc\u63a7\u5236\u5e73\u9762\u7684\u5904\u7406\u65b9\u5f0f<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222152746137.png\" alt=\"image-20241222152746137\" style=\"zoom:33%;\" \/><\/p>\n<p>\u4e3b\u8981\u4e3a\u4e86\u907f\u514d\u5206\u5e03\u5f0f\u7684\u5904\u7406\u8def\u7531\u89c4\u5219, \u7528\u96c6\u4e2d\u5316\u7684\u670d\u52a1\u5668\u5904\u7406\u89c4\u5219, \u670d\u52a1\u5668\u7528\u5357\u5411\u63a5\u53e3\u4e0e\u8def\u7531\u5668\u901a\u4fe1<\/p>\n<p>\u53ea\u8981\u7b26\u5408\u534f\u8bae, \u5404\u4e2a\u5382\u5546\u751f\u4ea7\u7684\u8def\u7531\u5668\u90fd\u53ef\u4ee5\u63a5\u6536\u6d41\u8868, \u4e0a\u62a5\u72b6\u6001, \u6210\u4e3a\u53ef\u7f16\u7a0b\u7f51\u7edc\u7684\u4e00\u90e8\u5206<\/p>\n<h3>SDN\u7684\u4e3b\u8981\u601d\u8def<\/h3>\n<ul>\n<li>\u7f51\u7edc\u8bbe\u5907\u6570\u636e\u5e73\u9762\u4e0e\u63a7\u5236\u5e73\u9762\u7684\u5206\u79bb<\/li>\n<li>\u8def\u7531\u5668, \u4ea4\u6362\u673a\u7b49\u7f51\u7edc\u8bbe\u5907\u8fdb\u4e00\u6b65\u62bd\u8c61\u4e3a: \u6309\u7167\u6d41\u8868\u8fdb\u884c<strong>PDU<\/strong>[\u5e27, \u5206\u7ec4]\u7684<strong>\u52a8\u4f5c<\/strong>[\u8f6c\u53d1, \u4e22\u5f03, \u6cdb\u6d2a, \u963b\u585e, &#8230;]<\/li>\n<li>\u8def\u7531, \u9632\u706b\u5899, NAT\u7b49\u529f\u80fd\u90fd\u662f\u7f51\u7edc\u5e94\u7528(app), \u4e0b\u8f7d\u4e0b\u6765\u5c31\u80fd\u90e8\u7f72<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222153525004.png\" alt=\"image-20241222153525004\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5782\u76f4\u7684\u96c6\u6210\u5e26\u6765\u4e86\u5784\u65ad, \u6c34\u5e73\u7684\u96c6\u6210\u4f1a\u5e26\u6765\u884c\u4e1a\u7684\u7e41\u8363<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222153728917.png\" alt=\"image-20241222153728917\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222153800173.png\" alt=\"image-20241222153800173\" style=\"zoom:33%;\" \/><\/p>\n<p>SDN\u4ea4\u6362\u673a\u4f7f\u7528\u6d41\u8868\uff08Flow Table\uff09\u6765\u5339\u914d\u7f51\u7edc\u6d41\u91cf\u3002\u6d41\u8868\u53ef\u4ee5\u5305\u542b\u591a\u4e2a\u5b57\u6bb5\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>MAC \u5730\u5740\uff08Layer 2\uff09<\/li>\n<li>IP \u5730\u5740\uff08Layer 3\uff09<\/li>\n<li>\u7aef\u53e3\u53f7\u3001\u534f\u8bae\uff08Layer 4\uff09<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222155213310.png\" alt=\"image-20241222155213310\" style=\"zoom:33%;\" \/><\/p>\n<h1>Chap5. \u7f51\u7edc\u5c42: \u63a7\u5236\u5e73\u9762<\/h1>\n<h2>5.1 \u5bfc\u8bba<\/h2>\n<p>\u7f51\u7edc\u5c42\u63a7\u5236\u5e73\u9762\u4e3b\u8981\u89e3\u51b3\u7aef\u5230\u7aef\u8def\u5f84\u7684\u8ba1\u7b97\u95ee\u9898<\/p>\n<ul>\n<li>\u8f6c\u53d1: \u6570\u636e\u5e73\u9762<\/li>\n<li>\u8def\u7531: \u63a7\u5236\u5e73\u9762<\/li>\n<\/ul>\n<p>\u4f20\u7edf\u8def\u7531\u9009\u62e9\u7b97\u6cd5, SDN\u65b9\u6cd5<\/p>\n<p>\u8fd9\u4e9b\u65b9\u6cd5\u5728\u4e92\u8054\u7f51\u4e0a\u7684\u5b9e\u73b0: OSPF, BGP, OpenFlow(SDN), ODL, ONOS, ICMP, &#8230;<\/p>\n<h2>5.2 \u8def\u7531\u9009\u62e9\u7b97\u6cd5<\/h2>\n<p>\u8def\u7531\u9009\u62e9\u7b97\u6cd5\u6709\u4e24\u7c7b: <\/p>\n<ul>\n<li>LS: link state<\/li>\n<li>DV: distance vector<\/li>\n<\/ul>\n<p>\u4ec0\u4e48\u662f\u8def\u7531? \u7f51\u7edc\u4e4b\u95f4\u7684\u8fde\u63a5\u975e\u5e38\u590d\u6742, \u8def\u7531\u5c31\u662f\u89e3\u51b3\u5982\u4f55\u4ece\u4e00\u4e2a\u4e3b\u673a\u5230\u53e6\u4e00\u4e2a\u4e3b\u673a\u5230\u8def\u5f84\u95ee\u9898<\/p>\n<p>\u7f51\u7edc\u5c42\u7684\u8def\u7531\u662f\u5b50\u7f51\u5230\u5b50\u7f51\u7684\u8def\u7531, \u4e0d\u53ef\u80fd\u8ba1\u7b97\u4e3b\u673a\u5230\u4e3b\u673a\u7684\u8def\u7531(\u6570\u91cf\u592a\u5927)<\/p>\n<h3>\u8def\u7531\u7684\u5b9a\u4e49<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222173241646.png\" alt=\"image-20241222173241646\" style=\"zoom:33%;\" \/><\/p>\n<p>\u56fe\u7684\u62bd\u8c61: \u8def\u7531\u662f\u5728\u4e00\u4e2a\u5e26\u6743\u56fe\u4e2d, \u7ed9\u51fa\u6e90\u8282\u70b9\u548c\u76ee\u6807\u8282\u70b9, \u7b97\u51fa\u7b26\u5408\u67d0\u79cd\u6307\u6807\u7684\u8def\u5f84<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222173835099.png\" alt=\"image-20241222173835099\" style=\"zoom:33%;\" \/><\/p>\n<p>\u6700\u4f18\u8def\u5f84\u5f62\u6210\u7684\u4e00\u5b9a\u662f\u6811, \u4e0d\u53ef\u80fd\u6709\u73af<\/p>\n<h3>\u8def\u7531\u7684\u539f\u5219<\/h3>\n<ul>\n<li>\u6b63\u786e\u6027: \u5fc5\u987b\u4fdd\u8bc1\u8def\u5f84\u6709\u6548\u4e14\u53ef\u8fbe<\/li>\n<li>\u7b80\u5355\u6027: \u8def\u7531\u7b97\u6cd5\u5e94\u8be5\u7b80\u5355, \u4e0d\u7528\u6d6a\u8d39\u5927\u91cf\u65f6\u95f4\u627e\u5230<strong>\u6700\u4f18<\/strong>, \u800c\u662f\u82b1\u8d39\u5c11\u91cf\u5b9e\u73b0\u627e\u5230<strong>\u8f83\u4f18<\/strong><\/li>\n<li>\u5065\u58ee\u6027: \u53ef\u4ee5\u9002\u5e94\u901a\u4fe1\u91cf\u548c\u62d3\u6251\u7684\u53d8\u5316<\/li>\n<li>\u7a33\u5b9a\u6027, \u516c\u5e73\u6027, \u6700\u4f18\u6027<\/li>\n<\/ul>\n<h3>\u8def\u7531\u7b97\u6cd5\u5206\u7c7b<\/h3>\n<p>\u89c6\u89d2\u5206\u7c7b<\/p>\n<ul>\n<li>\n<p>\u5168\u5c40\u89c6\u89d2: \u8def\u7531\u5668\u62e5\u6709\u5b8c\u6574\u7684\u56fe\u4fe1\u606f(\u62d3\u6251, \u4ee3\u4ef7), Link State<\/p>\n<\/li>\n<li>\n<p>\u5206\u5e03\u5f0f: \u8def\u7531\u5668\u53ea\u77e5\u9053\u4e0e\u5b83\u6709\u7269\u7406\u8fde\u63a5\u7684\u90bb\u5c45\u76f8\u5173\u7684\u4fe1\u606f, Distance Vector<\/p>\n<\/li>\n<\/ul>\n<p>\u53d8\u5316\u901f\u5ea6<\/p>\n<ul>\n<li>\u9759\u6001\u7b97\u6cd5: \u4e8b\u5148\u8ba1\u7b97\u597d\u7684\u8def\u7531\u8868, \u51e0\u4e4e\u4e0d\u53d8<\/li>\n<li>\u52a8\u6001\u7b97\u6cd5(\u5927\u591a\u6570\u73b0\u4ee3\u7b97\u6cd5): \u5468\u671f\u6027\u66f4\u65b0, \u81ea\u9002\u5e94\u7684<\/li>\n<\/ul>\n<h3>LS: \u8def\u7531\u7684\u5de5\u4f5c\u8fc7\u7a0b<\/h3>\n<p>LS\u8def\u7531\u9009\u62e9\u7b97\u6cd5\u4e2d, \u8def\u7531\u5668\u8981\u5f97\u77e5\u6574\u4e2a\u7f51\u7edc\u7684\u62d3\u6251<\/p>\n<ul>\n<li>\u8def\u7531\u5668\u901a\u8fc7\u6cdb\u6d2a\u4ea4\u6d41\u4fe1\u606f(\u8fd9\u90e8\u5206\u548c\u7b97\u6cd5\u65e0\u5173, \u5c5e\u4e8e\u534f\u8bae\u548c\u5b9e\u73b0)\n<ul>\n<li>\u53d1\u73b0\u76f8\u90bb\u8282\u70b9, \u83b7\u77e5\u5bf9\u65b9\u7f51\u7edc\u5730\u5740<\/li>\n<li>\u6d4b\u8bd5\u76f8\u90bb\u8282\u70b9\u4ee3\u4ef7(\u5ef6\u8fdf, \u5f00\u9500)<\/li>\n<li>\u7ec4\u88c5LS\u5206\u7ec4, \u63cf\u8ff0\u672c\u5730\u5230\u76f8\u90bb\u8282\u70b9\u7684\u4ee3\u4ef7\u60c5\u51b5<\/li>\n<li>\u5c40\u57df\u7f51\u6cdb\u6d2a\u5206\u7ec4, \u901a\u77e5\u5176\u4ed6\u8282\u70b9, \u540c\u65f6\u63a5\u6536\u5176\u4ed6\u8282\u70b9\u7684\u4fe1\u606f<\/li>\n<\/ul>\n<\/li>\n<li>\u4f7f\u7528Dijkstra\u7b97\u6cd5\u8ba1\u7b97\u672c\u5730\u5230\u5176\u4ed6\u7f51\u7edc\u7684\u6700\u4f18\u8def\u5f84(\u6c47\u96c6\u6811), \u5f97\u5230\u8def\u7531\u8868<\/li>\n<li>\u6309\u7167\u8def\u7531\u8868\u8f6c\u53d1<\/li>\n<\/ul>\n<h3>FS: \u6cdb\u6d2a\u4ea4\u6d41\u7ec6\u8282<\/h3>\n<p>\u4e3a\u4e86\u9632\u6b62\u7f51\u7edc\u98ce\u66b4, LS\u6cdb\u6d2a\u5206\u7ec4\u4f1a\u8bbe\u7f6eTTL\u548c\u7248\u672c\u53f7<\/p>\n<p>\u6b64\u5916, LS\u6cdb\u7ea2\u662f\u6709\u786e\u8ba4\u7684\u6cdb\u6d2a(\u53ef\u9760\u7684\u6cdb\u6d2a), \u5982\u679c\u6536\u4e0d\u5230\u786e\u8ba4, \u4f1a\u91cd\u590d\u53d1\u9001, \u5176\u76ee\u7684\u662f\u5fc5\u987b\u8ba9\u6240\u6709\u8282\u70b9\u6536\u5230\u53ef\u9760\u4fe1\u606f<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222203518193.png\" alt=\"image-20241222203518193\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222203535068.png\" alt=\"image-20241222203535068\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222203552921.png\" alt=\"image-20241222203552921\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222205732801.png\" alt=\"image-20241222205732801\" style=\"zoom:33%;\" \/><\/p>\n<h3>LS: Dijk\u8ba1\u7b97\u6700\u77ed\u8def<\/h3>\n<p>\u5982\u679c\u4f60\u5728\u60f3, \u8fd9\u662f\u4e0d\u662f\u53ea\u662f\u6734\u7d20\u7684Dijk, \u7b54\u6848\u662f\u6b63\u786e\u7684, \u4e00\u70b9\u6ca1\u53d8, \u751a\u81f3\u662fN^2\u7684Dijk, \u539f\u6c41\u539f\u5473<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222205950798.png\" alt=\"image-20241222205950798\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222210136699.png\" alt=\"image-20241222210136699\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222210233553.png\" alt=\"image-20241222210233553\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222214924940.png\" alt=\"image-20241222214924940\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222210316020.png\" alt=\"image-20241222210316020\" style=\"zoom:33%;\" \/><\/p>\n<h3>DV\u7b97\u6cd5: \u57fa\u672c\u601d\u60f3<\/h3>\n<p>\u590d\u4e60: DV\u7b97\u6cd5(Distance Vector Routing), \u52a8\u6001\u8def\u7531\u9009\u62e9\u7b97\u6cd5\u4e4b\u4e8c, \u4e4b\u4e00\u662f\u4e0a\u9762\u8bf4\u7684LS\u7b97\u6cd5(Link State)<\/p>\n<ul>\n<li>\u5404\u8def\u7531\u5668\u7ef4\u62a4\u4e00\u5f20\u8868, \u7ed3\u6784[To, Next, Cost], \u4ee5\u5b50\u7f51\u4e3a\u5355\u4f4d<\/li>\n<li>\u5404\u8def\u7531\u5668\u4e0e\u90bb\u5c45\u5b9a\u65f6\u4ea4\u6362\u8def\u7531\u8868<\/li>\n<li>\u6839\u636e\u83b7\u5f97\u7684\u4fe1\u606f\u66f4\u65b0\u8def\u7531\u8868<\/li>\n<\/ul>\n<p>\u89c1\u4e0b\u56feA, \u901a\u8fc7XYZ\u7684\u4fe1\u606f\u66f4\u65b0\u81ea\u5df1\u7684\u8def\u7531\u8868, \u5176\u4e2d\u4ea4\u6362\u7684\u4fe1\u606f\u88ab\u79f0\u4f5c<strong>\u8ddd\u79bb\u77e2\u91cf<\/strong><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222215826116.png\" alt=\"image-20241222215826116\" style=\"zoom:33%;\" \/><\/p>\n<p>DV\u662f<strong>\u5f02\u6b65\u7684, \u8fed\u4ee3\u5f0f\u7684\u7b97\u6cd5<\/strong>, \u8981\u901a\u8fc7\u591a\u8f6e\u8fed\u4ee3\u624d\u80fd\u6536\u655b\u5230\u5b9e\u9645\u503c<\/p>\n<ul>\n<li>\u76f8\u90bb\u8282\u70b9\u7684\u4ee3\u4ef7\u901a\u8fc7\u5b9e\u6d4b\u5f97\u77e5<\/li>\n<li>\u5176\u4ed6\u8282\u70b9\u7684\u4ee3\u4ef7\u901a\u8fc7\u901a\u544a\u5f97\u77e5<\/li>\n<\/ul>\n<p>\u89e6\u53d1\u672c\u5730\u66f4\u65b0\u8def\u7531\u8868\u7684\u4e8b\u4ef6\u6709<\/p>\n<ul>\n<li>\u672c\u5730\u94fe\u8def\u4ee3\u4ef7\u53d8\u5316(\u548c\u90bb\u5c45\u7684\u8fde\u63a5\u8d28\u91cf\u6539\u53d8)<\/li>\n<li>\u6536\u5230\u4e86\u90bb\u5c45\u53d1\u6765\u7684DV<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222221236717.png\" alt=\"image-20241222221236717\" style=\"zoom:33%;\" \/><\/p>\n<h3>DV\u7684\u7279\u70b9: \u597d\u6d88\u606f\u4f20\u5f97\u5feb, \u574f\u6d88\u606f\u4f20\u5f97\u6162<\/h3>\n<p>\u5728\u4e0b\u56fe\u4e2d, AB\u6700\u5f00\u59cb\u662f\u65ad\u5f00\u7684, \u67d0\u4e2a\u65f6\u523b\u7a81\u7136\u8054\u901a\u4e86, \u5219B\u6700\u5148\u5f97\u77e5, c(A)=1, B\u5f00\u59cb\u5e7f\u64ad<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222222337602.png\" alt=\"image-20241222222337602\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u4e0b\u56fe\u4e2d, AB\u6700\u5f00\u59cb\u662f\u8fde\u63a5\u7684\u7684, \u67d0\u4e2a\u65f6\u523b\u7a81\u7136\u65ad\u5f00\u4e86, \u5219B\u6700\u5148\u5f97\u77e5B-&gt;A\u4e0d\u53ef\u8fbe, \u4f46\u662fC\u4f1a\u58f0\u79f0A\u53ef\u8fbe(\u865a\u5047\u7684, C\u8981\u901a\u8fc7B\u624d\u80fd\u8fbe\u5230A)<br \/>\nC\u865a\u5047\u7684\u58f0\u79f0\u4f1a\u8ba9B\u4ee5\u4e3aB-&gt;C-&gt;A\u53ef\u8fbe, \u6b64\u65f6\u5f62\u6210\u4e86\u73af\u8def(\u73af\u8def\u7684\u89e3\u51b3\u5e94\u8be5\u7528TTL)<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222222408101.png\" alt=\"image-20241222222408101\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u4e0a\u56fe\u7684\u60c5\u51b5\u4e0b, \u4f1a\u7ecf\u8fc7\u5f88\u591a\u6b21\u63a8\u6f14, \u624d\u80fd\u77e5\u9053A\u4e0d\u53ef\u8fbe<\/p>\n<h3>DV: \u6c34\u5e73\u5206\u88c2\u7b97\u6cd5<\/h3>\n<p>\u6c34\u5e73\u5206\u88c2\u7b97\u6cd5\u7528\u6765\u51cf\u7f13\u4e0a\u9762\u7684\u574f\u6d88\u606f\u4f20\u64ad\u6162\u4e0e\u73af\u8def\u95ee\u9898<strong>(\u6ce8\u610f, \u4e0d\u662f\u89e3\u51b3)<\/strong><\/p>\n<p>\u6c34\u5e73\u5206\u5272\u7684\u57fa\u672c\u601d\u60f3\u662f: \u4e00\u4e2a\u8def\u7531\u5668\u4e0d\u4f1a\u5411\u5b83\u5b66\u5230\u67d0\u6761\u8def\u7531\u7684\u63a5\u53e3\u518d\u6b21\u901a\u544a\u8fd9\u6761\u8def\u7531<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222223100588.png\" alt=\"image-20241222223100588\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5728\u4e0a\u56fe\u4e2d, \u4f53\u73b0\u4e3a: A\u548cB\u65ad\u8054\u4e86, C\u77e5\u9053, \u81ea\u8eab\u8fde\u63a5A\u8981\u901a\u8fc7B, \u6240\u4ee5B\u662fA\u7684\u6743\u5a01\u4fe1\u606f\u6765\u6e90, \u5219, C\u4ea4\u7ed9B\u5173\u4e8eA\u7684DV\u662f\u8c26\u865a\u7684(\u751f\u6210\u81ea\u5df1\u4e0d\u53ef\u8fbe).  \u4f46\u540c\u65f6, C\u5728\u4ea4\u7ed9D\u5173\u4e8eA\u7684DV\u65f6, \u4ea4\u4ed8\u771f\u5b9e\u503c, \u8fd9\u662f\u56e0\u4e3aD\u8981\u901a\u8fc7C\u7ed9A\u53d1\u6d88\u606f, C\u76f8\u5bf9\u4e8eD\u66f4\u52a0\u6743\u5a01<\/p>\n<p>C\u5c06A\u7684\u4fe1\u606f\u5206\u88c2\u6210\u8c26\u865a\u548c\u4e0d\u8c26\u865a\u7684\u4e24\u4efd\u4f20\u64ad, \u8fd9\u5c31\u662f\u6c34\u5e73\u5206\u88c2\u7b97\u6cd5<\/p>\n<p>\u4e0b\u56fe\u4e2d\u7684\u4f8b\u5b50, D\u4e0d\u53ef\u8fbe\u7684\u6d88\u606f\u4ecd\u7136\u9700\u8981\u5f88\u591a\u8f6e\u8fed\u4ee3\u624d\u80fd\u88ab\u7f51\u7edc\u8ba4\u8bc6\u5230<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222224005884.png\" alt=\"image-20241222224005884\" style=\"zoom:33%;\" \/><\/p>\n<h3>DV\u7b97\u6cd5: \u5b9e\u4f8b<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222224124989.png\" alt=\"image-20241222224124989\" style=\"zoom:33%;\" \/><\/p>\n<p>\u6bcf\u6b21\u8fed\u4ee3\u90fd\u8981\u8c03\u7528bellman-ford\u65b9\u7a0b<\/p>\n<p>\u4e0a\u56fe\u4e2d\u7ecf\u8fc73\u6b21\u8fed\u4ee3, \u7f51\u7edc\u6536\u655b\u5230\u4e86\u771f\u5b9e\u60c5\u51b5<\/p>\n<h3>LS vs DV<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222224251237.png\" alt=\"image-20241222224251237\" style=\"zoom:33%;\" \/><\/p>\n<h2>5.3 \u81ea\u6cbb\u7cfb\u7edf\u5185\u90e8\u7684\u8def\u7531\u9009\u62e9: RIP &amp; OSPF<\/h2>\n<p>\u4e5f\u53eb\u5185\u90e8\u7f51\u5173\u534f\u8bae, \u4e3b\u8981\u6709\u4e24\u79cd: RIP, OSPF<\/p>\n<p>\u7b97\u6cd5\u6bd4\u8f83\u62bd\u8c61, \u534f\u8bae\u66f4\u5177\u4f53\u4e00\u4e9b<\/p>\n<h3>RIP: \u57fa\u4e8eDV\u7684\u534f\u8bae\u5b9e\u73b0<\/h3>\n<ul>\n<li>\u91c7\u7528\u4e86\u8df3\u6570\u4f5c\u4e3a\u4ee3\u4ef7, \u6700\u5927\u4ee3\u4ef7=15, 16\u8868\u793a\u4e0d\u53ef\u8fbe<\/li>\n<li>\u6bcf30s\u4ea4\u6362\u4e00\u6b21DV, \u5bf9\u65b9\u8bf7\u6c42\u5219\u7acb\u5373\u4ea4\u6362<\/li>\n<li>\u6bcf\u4e2a\u901a\u544a\u6700\u591a\u5305\u542b25\u4e2a\u76ee\u6807\u5b50\u7f51(RIP\u662f\u7528\u4e8e\u5c0f\u7f51\u7edc\u7684\u534f\u8bae)<\/li>\n<\/ul>\n<p>\u4e0b\u9762\u63cf\u8ff0\u4e00\u4e2aRIP\u5b9e\u4f8b, \u8bf7\u770bD\u8def\u7531\u5668\u7684\u8def\u7531\u8868, \u6ce8\u610f\u4ee3\u4ef7\u662fhop<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222225618468.png\" alt=\"image-20241222225618468\" style=\"zoom:33%;\" \/><\/p>\n<p>D\u7684\u8def\u7531\u8868\u5728\u6536\u5230A\u7684DV\u540e\u66f4\u65b0<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222225657567.png\" alt=\"image-20241222225657567\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222225810831.png\" alt=\"image-20241222225810831\" style=\"zoom:33%;\" \/><\/p>\n<p>\u6bd2\u6027\u9006\u8f6c\u5c5e\u4e8e\u6c34\u5e73\u5206\u7c7b, \u4e0a\u9762\u4ecb\u7ecd\u8fc7<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222225937431.png\" alt=\"image-20241222225937431\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>RIP\u7684\u901a\u8baf\u62a5\u6587\u662fUDP\u7684, \u5c01\u88c5\u5728IP\u6570\u636e\u62a5\u4e2d\u53d1\u9001<\/p>\n<\/blockquote>\n<h3>OSPF: \u57fa\u4e8eLS\u7684\u534f\u8bae\u5b9e\u73b0<\/h3>\n<ul>\n<li>LS\u7b97\u6cd5\n<ul>\n<li>LS\u6cdb\u6d2a\u5206\u7ec4\u5728\u7f51\u7edc\u4e2d(\u4e00\u4e2aAS\u5185\u90e8)\u5206\u53d1<\/li>\n<li>\u6bcf\u4e2a\u8282\u70b9\u7ef4\u62a4\u5168\u5c40\u7f51\u7edc\u4fe1\u606f(\u62d3\u6251+\u4ee3\u4ef7)<\/li>\n<li>Dijk\u8ba1\u7b97\u6700\u6bb5\u8def<\/li>\n<\/ul>\n<\/li>\n<li>OSPF\u901a\u544a\u643a\u5e26: [\u672c\u5730IP, \u901a\u544a\u7248\u672c, \u672c\u5730\u5230\u90bb\u5c45\u7684\u4ee3\u4ef7]<\/li>\n<li>OSPF\u901a\u544a\u4f1a\u5728AS\u6cdb\u6d2a<\/li>\n<\/ul>\n<blockquote>\n<p>\u540d\u6b21\u89e3\u91ca: AS, Autonomous System, \u81ea\u6cbb\u7cfb\u7edf, \u662fOSPF\u534f\u8bae\u4e2d, \u903b\u8f91\u4e0a\u5bf9\u4e8e\u67d0\u4e2a\u5171\u4eab\u8def\u7531\u7b56\u7565\u7684\u7f51\u7edc\u7684\u79f0\u547c<\/p>\n<p>OSPF\u7684\u901a\u8baf\u62a5\u6587\u662fIP\u6570\u636e\u62a5, \u4e0d\u4f7f\u7528\u4efb\u4f55\u4f20\u8f93\u5c42\u534f\u8bae<\/p>\n<\/blockquote>\n<p>OSPF\u6709\u5f88\u591a\u9ad8\u7ea7\u7279\u6027, \u4ee5\u4e0b\u662fRIP\u6ca1\u6709\u7684<\/p>\n<ul>\n<li>OSPF\u6709\u5b89\u5168\u7279\u6027<\/li>\n<li>OSPF\u5141\u8bb8\u4e24\u6761\u4ee3\u4ef7\u76f8\u540c\u7684\u8def\u5f84, \u800cRIP\u4e0d\u5141\u8bb8<\/li>\n<li>OSPF\u5141\u8bb8\u591a\u91cd\u4ee3\u4ef7(\u591a\u79cd\u6307\u6807\u7684\u6700\u4f18\u8def\u5f84, \u8df3\u6570? \u62e5\u585e\u7a0b\u5ea6? )<\/li>\n<li>Multicast OSPF\u652f\u6301\u591a\u64ad\u534f\u8bae<\/li>\n<li>\u5728\u5927\u578b\u7f51\u7edc\u4e2d\u652f\u6301\u5c42\u6b21\u7684OSPF(\u533a\u57df\u5185\u6cdb\u6d2a)<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241222231008212.png\" alt=\"image-20241222231008212\" style=\"zoom:33%;\" \/><\/p>\n<h2>5.4 ISP\u4e4b\u95f4\u7684\u8def\u7531\u9009\u62e9: BGP<\/h2>\n<p>\u4e0a\u9762\u7684LS, DV, \u90fd\u662f\u89e3\u51b3<strong>\u4e00\u4e2a\u5e73\u9762<\/strong>\u7684\u8def\u7531\u95ee\u9898<\/p>\n<ul>\n<li>\u6240\u6709\u8def\u7531\u5668\u5730\u4f4d\u4e00\u6837, \u901a\u8fc7\u4ea4\u6d41\u786e\u5b9a\u8def\u7531\u7b56\u7565<\/li>\n<\/ul>\n<p>\u5728\u4e92\u8054\u7f51\u7684\u6570\u91cf\u7ea7\u4e0a, \u56e0\u4e3a\u8282\u70b9\u8fc7\u4e8e\u591a, \u4e0d\u80fd\u91c7\u7528\u5e73\u9762\u7684\u8def\u7531\u7b97\u6cd5<\/p>\n<ul>\n<li>\u5404\u4e2a\u7f51\u7edc\u5185\u90e8\u4e5f\u9700\u8981\u9690\u79c1\u6027, \u81ea\u5df1\u89c4\u5b9a\u81ea\u5df1\u7684\u8def\u7531\u7b97\u6cd5<\/li>\n<\/ul>\n<h3>\u5c42\u6b21\u8def\u7531: AS<\/h3>\n<p>\u4e92\u8054\u7f51\u5c06\u7f51\u7edc\u5206\u6210\u4e86\u82e5\u5e72\u81ea\u6cbb\u533a(AS), \u6bcf\u4e2aAS\u6709\u4e00\u4e2a\u7f16\u53f7, ASN<\/p>\n<p>AS\u662f<strong>\u8def\u7531\u903b\u8f91\u4e0a\u7684, \u9664\u4e92\u8054\u7f51\u672c\u8eab\u5916\u6700\u5927\u7684\u8def\u7531\u5c3a\u5ea6\u5355\u4f4d<\/strong>, \u5927\u6570\u91cf\u6982\u670910\u4e07\u7ea7\u522b<\/p>\n<ul>\n<li>AS\u5185\u90e8\u8def\u7531\u81ea\u6cbb, \u8fd0\u884c\u540c\u4e00\u79cd\u8def\u7531\u534f\u8bae(\u6bd4\u5982OSPF, RIP, \u65e0\u6240\u8c13)<\/li>\n<li>AS\u5bf9\u5916\u53ea\u9700\u5ba3\u79f0\u4e00\u6761\u5b50\u7f51\u53ef\u8fbe\u4fe1\u606f<\/li>\n<li>AS\u4e4b\u95f4\u7684\u8def\u7531, \u6bcf\u4e2aAS\u90fd\u662f\u4e00\u4e2a\u70b9<\/li>\n<\/ul>\n<blockquote>\n<p>\u5b9e\u9645\u4e0aAS\u5185\u90e8\u4e5f\u53ef\u4ee5\u7ee7\u7eed\u5206\u5c42, \u8fd0\u884c\u591a\u79cd\u8def\u7531\u534f\u8bae<\/p>\n<p>\u77e5\u540d\u7684AS\u6709Google, FaceBook, \u4e2d\u56fd\u7535\u4fe1\u7b49, \u4e5f\u6709\u4e00\u4e9b\u6bd4\u8f83\u5c0f\u578b\u7684<\/p>\n<\/blockquote>\n<p>\u5bf9\u4e8eAS\u5185\u90e8, \u6709\u4e30\u5bcc\u7684\u8def\u7531\u534f\u8bae, \u6bd4\u5982RIP, OSPF, \u8fd8\u6709\u4e00\u4e9b\u79c1\u6709\u534f\u8bae, \u6bd4\u5982\u601d\u79d1\u8def\u7531\u5668<\/p>\n<p>\u7f51\u5173\u8def\u7531\u5668, \u8fb9\u754c\u8def\u7531\u5668: \u8fde\u63a5AS\u4e4b\u95f4\u7684\u8def\u7531\u5668<\/p>\n<h3>AS\u4e4b\u95f4\u7684\u8def\u7531: BGP\u534f\u8bae<\/h3>\n<p>BGP\u534f\u8bae\u662f\u4e8b\u5b9e\u4e0a\u7684\u534f\u8bae, \u4e0d\u662f\u89c4\u5b9a\u7684, \u800c\u662f\u81ea\u884c\u53d1\u5c55\u51fa\u7684<\/p>\n<ul>\n<li>\u5c06AS\u7c98\u5728\u4e00\u8d77\u7684\u6d47\u6c34<\/li>\n<\/ul>\n<p>\u6bcf\u4e2aAS\u53ef\u4ee5\u6267\u884c<\/p>\n<ul>\n<li>eBGP: \u4ece\u76f8\u90bb\u7684AS\u83b7\u53d6\u5b50\u7f51\u53ef\u8fbe\u4fe1\u606f<\/li>\n<li>iBGP: \u5c06\u83b7\u5f97\u7684\u5b50\u7f51\u53ef\u8fbe\u4fe1\u606f\u4f20\u7ed9AS\u5185\u90e8\u7684\u6240\u6709\u8def\u7531\u5668<\/li>\n<\/ul>\n<p>\u8def\u7531\u5668\u901a\u8fc7\u5b50\u7f51\u53ef\u8fbe\u4fe1\u606f\u548c\u7b56\u7565\u51b3\u5b9a\u5230\u8fbe\u5b50\u7f51\u7684\u8def\u5f84<\/p>\n<ul>\n<li>\u5b50\u7f51\u53ef\u4ee5\u4e3b\u52a8\u901a\u544a\u81ea\u5df1\u7684\u4f4d\u7f6e<\/li>\n<li>\u57fa\u4e8e\u6539\u8fdb\u7684DV\u7b97\u6cd5, \u4e0d\u4ec5\u4ec5\u662f\u8ddd\u79bb\u77e2\u91cf, \u8fd8\u5305\u62ec\u8be6\u7ec6\u8def\u5f84(AS\u5e8f\u53f7\u5217\u8868), \u907f\u514d\u4e86DV\u7b97\u6cd5\u7684\u8def\u7531\u73af\u8def\u95ee\u9898<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223122134494.png\" alt=\"image-20241223122134494\" style=\"zoom:33%;\" \/><\/p>\n<ul>\n<li>1c, 2a, 2c, 3a\u662f\u7f51\u5173<\/li>\n<li>\u7f51\u5173\u4e00\u65b9\u9762\u6536\u96c6AS\u5185\u7684\u5b50\u7f51\u53ef\u8fbe\u4fe1\u606f, \u53e6\u4e00\u65b9\u9762\u5411\u5916\u901a\u544a<\/li>\n<\/ul>\n<h3>BGP\u57fa\u672c\u539f\u7406<\/h3>\n<p>\u4e0b\u6587\u7684BGP\u4f1a\u8bdd, \u5305\u542beBGP\u548ciBGP<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223122640200.png\" alt=\"image-20241223122640200\" style=\"zoom:33%;\" \/><\/p>\n<p>BGP\u901a\u544a(BGP- advertisement): \u8fd9\u4e9b\u5b50\u7f51\u7684\u6d88\u606f\u4f60\u53ef\u4ee5\u8f6c\u53d1\u7ed9\u6211(\u6211\u53ef\u4ee5\u4f5c\u4e3a\u4e0b\u4e00\u8df3), \u540c\u65f6\u5305\u542b\u4e86\u9014\u5f84\u7684AS\u4fe1\u606f(\u8fd9\u662fDV\u6ca1\u6709\u7684), \u548c\u4e0b\u4e00\u8df3\u76ee\u6807<\/p>\n<p>AS\u5185\u90e8\u7684\u8def\u7531\u5173\u6ce8\u6027\u80fd, \u4f46\u662fAS\u4e4b\u95f4\u7684\u8def\u7531\u5f88\u5f3a\u8c03\u7b56\u7565(\u653f\u6cbb\u7b56\u7565, \u7ecf\u6d4e\u7b56\u7565, \u5b57\u9762\u610f\u601d\u7684)<\/p>\n<ul>\n<li>\u4e0d\u60f3\u7ecf\u8fc7\u67d0\u4e2aAS<\/li>\n<li>\u5fc5\u987b\u7ecf\u8fc7\u67d0\u4e2aAS<\/li>\n<\/ul>\n<p>\u8fb9\u754c\u8def\u7531\u5668\u4f1a\u6839\u636e\u7b56\u7565\u63a5\u53d7\/\u62d2\u7eddeBGP\u901a\u544a, \u6b64\u5916, \u8fd8\u8981\u51b3\u5b9a\u662f\u5426\u8981\u8f6c\u53d1<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223124116448.png\" alt=\"image-20241223124116448\" style=\"zoom:33%;\" \/><\/p>\n<blockquote>\n<p>BGP\u534f\u8bae\u901a\u8fc7TCP\u534f\u8bae\u4ea4\u6362\u62a5\u6587, \u9700\u8981\u7ef4\u62a4\u8def\u7531\u5668\u5728\u7ebf\u72b6\u6001<\/p>\n<\/blockquote>\n<p>\u533a\u57df\u5185\u7684\u5b50\u7f51\u53ef\u8fbe\u4fe1\u606f, \u662f\u7531iBGP, eBGP\u5171\u540c\u51b3\u5b9a\u7684<\/p>\n<h3>BGP: \u8def\u5f84\u9009\u62e9<\/h3>\n<p>\u8def\u7531\u5668\u4f1a\u83b7\u5f97\u5230\u8fbe\u4e00\u4e2a\u5b50\u7f51\u524d\u7f00\u7684\u591a\u4e2a\u8def\u5f84, \u901a\u8fc7\u591a\u79cd\u5185\u90e8\u7b97\u6cd5\u51b3\u5b9a\u9009\u62e9\u54ea\u4e00\u4e2a<\/p>\n<ul>\n<li>\u5185\u90e8\u504f\u597d\u8bbe\u7f6e<\/li>\n<li>\u6700\u77edAS\u8df3\u6570<\/li>\n<li>\u6700\u8fd1Next-Hop: \u70ed\u571f\u8c46\u8def\u7531, \u4e0d\u64cd\u5fc3AS\u95f4\u4ee3\u4ef7<\/li>\n<\/ul>\n<h2>5.5 SDN\u63a7\u5236\u5e73\u9762<\/h2>\n<p>\u548c\u524d\u9762\u8bb2\u7684\u4e00\u6837<\/p>\n<h2>5.6 ICMP: \u4e92\u8054\u7f51\u63a7\u5236\u62a5\u6587\u534f\u8bae<\/h2>\n<p>\u4e3b\u8981\u662f\u4e3b\u673a, \u8def\u7531\u5668, \u7f51\u5173\u7684\u7f51\u7edc\u63a7\u5236\u4fe1\u606f<\/p>\n<ul>\n<li>\u9519\u8bef\u62a5\u544a: \u5730\u5740\u4e0d\u53ef\u8fbe, \u8fde\u63a5\u8d85\u65f6, &#8230;<\/li>\n<li>Echo\u8bf7\u6c42\u548c\u56de\u590d: ping<\/li>\n<\/ul>\n<p>ICMP\u5728\u7f51\u7edc\u5c42, \u4f46\u662f\u5728IP\u534f\u8bae\u7684\u4e0a\u65b9<\/p>\n<h1>Chap6. \u94fe\u8def\u5c42\u4e0e\u5c40\u57df\u7f51<\/h1>\n<p>\u4e3a\u4ec0\u4e48\u53eb\u94fe\u8def\u5c42\u4e0e\u5c40\u57df\u7f51(LAN)? \u56e0\u4e3a\u5e7f\u57df\u7f51(WAN)\u7684\u94fe\u8def\u5c42\u6bd4\u8f83\u7b80\u5355<\/p>\n<p>\u6211\u4eec\u5148\u5b66\u4e60LAN\u548cWAN\u901a\u7528\u7684\u94fe\u8def\u5c42\u529f\u80fd, \u518d\u8bb2\u89e3LAN\u72ec\u6709\u7684\u90e8\u5206<\/p>\n<ul>\n<li>\u5e7f\u57df\u7f51\u4e00\u822c\u662f\u70b9\u5bf9\u70b9\u7684(\u6d77\u5e95\u5149\u7f06)<\/li>\n<li>\u5c40\u57df\u7f51\u4e00\u822c\u662f\u591a\u70b9\u7684(Wi-Fi)<\/li>\n<\/ul>\n<p>\u548c\u524d\u9762\u7684\u90e8\u5206\u4e00\u6837, \u6211\u4eec\u5148\u5b66\u4e60\u539f\u7406, \u518d\u4ecb\u7ecd\u5b9e\u8df5<\/p>\n<h2>6.1 \u5f15\u8bba\u548c\u670d\u52a1<\/h2>\n<p>\u89c4\u5b9a\u4e00\u4e9b\u672f\u8bed:<\/p>\n<ul>\n<li>\u8282\u70b9(nodes): \u4e3b\u673a, \u8def\u7531\u5668, \u4ea4\u6362\u673a, \u7f51\u6865, \u90fd\u662f\u8282\u70b9<\/li>\n<li>\u94fe\u8def(links): \u6cbf\u7740\u901a\u4fe1\u8def\u5f84,\u8fde\u63a5\u76f8\u90bb\u8282\u70b9\u901a\u4fe1\u7684\u4fe1\u9053\n<ul>\n<li>\u6709\u7ebf\u94fe\u8def, \u65e0\u7ebf\u94fe\u8def, \u7b49<\/li>\n<\/ul>\n<\/li>\n<li>\u5e27(frame): \u94fe\u8def\u5c42\u7684\u534f\u8bae\u6570\u636e\u5355\u5143(PDU)<\/li>\n<\/ul>\n<p>\u94fe\u8def\u5c42\u89e3\u51b3\u7684\u662f\u70b9\u5230\u70b9\u7684\u529f\u80fd, \u76f8\u6bd4\u4e4b\u4e0b, \u7f51\u7edc\u5c42\u89e3\u51b3\u7684\u662f\u7aef\u5230\u7aef\u7684\u529f\u80fd<\/p>\n<blockquote>\n<p>\u94fe\u8def\u5c42: \u5728\u76f8\u90bb\u4e24\u70b9\u95f4, \u4f20\u8f93\u4ee5\u5e27\u4e3a\u5355\u4f4d\u7684\u6570\u636e<\/p>\n<\/blockquote>\n<p>\u4e0d\u540c\u7684\u8df3\u4e2d, IP\u5206\u7ec4\u53ef\u80fd\u5c01\u88c5\u5728\u4e0d\u540c\u7c7b\u578b\u7684\u5e27\u4e2d(\u94fe\u8def\u5c42\u534f\u8bae). \u8def\u7531\u5668\u6536\u5230\u5e27\u540e, \u4f1a\u63d0\u53d6\u5176\u4e2d\u7684IP\u5206\u7ec4, \u6839\u636e\u8f6c\u53d1\u76ee\u6807\u7684MAC\u534f\u8bae, \u91cd\u65b0\u5c01\u88c5\u4e00\u4e2a\u5e27<\/p>\n<ul>\n<li>\u7b2c\u4e00\u8df3: \u4ee5\u592a\u7f51<\/li>\n<li>\u7b2c\u4e8c\u8df3: \u5e27\u4e2d\u7ee7\u94fe\u8def<\/li>\n<li>\u7b2c\u4e09\u8df3: 802.11<\/li>\n<\/ul>\n<h3>\u94fe\u8def\u5c42\u670d\u52a1<\/h3>\n<ul>\n<li>\u6210\u5e27: \u6570\u636e\u62a5\u88ab\u5c01\u88c5\u5728\u5e27\u4e2d, \u88c5\u4e0a\u5e27\u5934\u90e8, \u5e27\u5c3e\u90e8<\/li>\n<li>\u63a5\u5165: \u5982\u679c\u91c7\u7528\u5171\u4eab\u6027\u4ecb\u8d28, \u63a5\u5165\u65f6\u5206\u914d\u4f7f\u7528\u6743<\/li>\n<li>\u53ef\u9760(\u90e8\u5206): \u6bd4\u5982802.11\u8981\u6c42\u786e\u8ba4\n<ul>\n<li>\u5149\u7ea4, \u53cc\u7ede\u7ebf, \u8fd9\u6837\u7684\u53ef\u9760\u4ecb\u8d28\u5f88\u5c11\u7528<\/li>\n<li>\u65e0\u7ebf\u7ecf\u5e38\u7528, \u51fa\u9519\u7387\u592a\u9ad8\u4e86<\/li>\n<\/ul>\n<\/li>\n<li>\u6d41\u91cf\u63a7\u5236: \u53d1\u9001, \u63a5\u6536\u65b9\u901f\u5ea6\u5339\u914d<\/li>\n<li>\u9519\u8bef\u68c0\u6d4b\u4e0e\u6062\u590d<\/li>\n<li>\u534a\u53cc\u5de5\u4e0e\u5168\u53cc\u5de5<\/li>\n<\/ul>\n<blockquote>\n<p>\u53ea\u6709\u90e8\u5206\u94fe\u8def\u5c42\u670d\u52a1\u662f\u53ef\u9760\u7684, \u6240\u4ee5\u7f51\u7edc\u5c42\u4e0d\u53ef\u9760<\/p>\n<\/blockquote>\n<h3>\u94fe\u8def\u5c42\u5728\u54ea\u91cc\u5b9e\u73b0: \u7f51\u5361<\/h3>\n<p>\u6bcf\u4e00\u4e2a\u4e3b\u673a, \u8def\u7531\u5668, \u4ea4\u6362\u673a\u7684\u7f51\u5361\u4e0a<\/p>\n<ul>\n<li>\n<p>\u8def\u7531\u5668, \u4ea4\u6362\u673a\u6709\u591a\u5f20\u7f51\u5361<\/p>\n<\/li>\n<li>\n<p>\u4ee5\u592a\u7f51\u5361, 802.11\u7f51\u5361, &#8230;<\/p>\n<\/li>\n<\/ul>\n<blockquote>\n<p>\u7f51\u5361\u4e5f\u53eb\u7f51\u7edc\u9002\u914d\u5668(Network Adapter), \u5b9e\u73b0\u4e86\u94fe\u8def\u5c42\u548c\u76f8\u5e94\u7684\u7269\u7406\u529f\u80fd, \u548c\u4e3b\u673a\u7cfb\u7edf\u603b\u7ebf\u8fde\u63a5<\/p>\n<p>\u7f51\u5361\u662f\u8f6f\u4ef6, \u786c\u4ef6, \u56fa\u4ef6\u7684\u96c6\u5408\u4f53<\/p>\n<\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223180635179.png\" alt=\"image-20241223180635179\" style=\"zoom:33%;\" \/><\/p>\n<p>\u867d\u7136\u4e0a\u56fe\u533a\u5206\u7684\u53d1\u9001\u548c\u63a5\u6536\u65b9, \u5b9e\u9645\u60c5\u51b5\u4e2d, \u4e00\u5f20\u7f51\u5361\u53ef\u4ee5\u540c\u65f6\u6536\u53d1<\/p>\n<h2>6.2 \u68c0\u9519\u4e0e\u7ea0\u9519<\/h2>\n<p>\u540d\u8bcd\u89e3\u91ca: <\/p>\n<ul>\n<li>\n<p>EDC, \u5dee\u9519\u68c0\u6d4b\u4e0e\u7ea0\u6b63\u4f4d(\u4e5f\u53eb\u5197\u4f59\u4f4d)<\/p>\n<\/li>\n<li>\n<p>D, \u6570\u636e\u672c\u8eab<\/p>\n<\/li>\n<\/ul>\n<p>\u6821\u9a8c\u901a\u8fc7\u4e5f\u4e0d\u4e00\u5b9a\u5bf9, \u6821\u9a8c\u4e0d\u901a\u8fc7\u4e00\u5b9a\u9519<\/p>\n<blockquote>\n<p>\u901a\u8fc7\u6821\u9a8c\u7684\u9519\u8bef\u53eb\u505a\u6b8b\u5b58\u9519\u8bef, \u6570\u636e\u91cf\u8d8a\u5927, \u6b8b\u5b58\u9519\u8bef\u8d8a\u5c11<\/p>\n<\/blockquote>\n<h3>\u5947\u5076\u6821\u9a8c<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223181155433.png\" alt=\"image-20241223181155433\" style=\"zoom:33%;\" \/><\/p>\n<h3>Internet\u6821\u9a8c\u548c: checksum<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223181324561.png\" alt=\"image-20241223181324561\" style=\"zoom:33%;\" \/><\/p>\n<h3>CRC: \u5faa\u73af\u5197\u4f59\u6821\u9a8c\u7801<\/h3>\n<p>CRC\u5c06D\u770b\u4f5c\u4e8c\u8fdb\u5236\u6570\u636e, \u4e8c\u8fdb\u5236\u6570\u636e\u53ef\u4ee5\u5bf9\u5e94\u591a\u9879\u5f0f<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223181741780.png\" alt=\"image-20241223181741780\" style=\"zoom:50%;\" \/><\/p>\n<p>\u53d1\u9001\u65b9: <\/p>\n<ul>\n<li>\u6784\u9020r\u4f4d\u7684EDC\u6a21\u5f0fR, \u4ee4D-R\u53ef\u4ee5\u6574\u9664G<\/li>\n<\/ul>\n<p>\u63a5\u6536\u65b9:<\/p>\n<ul>\n<li>\u6536\u5230\u4fe1\u606f, \u76f4\u63a5\u9664\u4ee5G, \u68c0\u67e5\u6574\u9664\u6027<\/li>\n<\/ul>\n<p>\u5176\u4e2d\u7684G\u662f\u53cc\u65b9\u7ea6\u5b9a\u7684, r+1\u4f4d\u7684\u6a21\u5f0f<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223182647659.png\" alt=\"image-20241223182647659\" style=\"zoom:50%;\" \/><\/p>\n<p>\u5728\u6784\u9020\u65f6, \u76ee\u6807\u662f\u4ee4<br \/>\n$$<br \/>\nD \\cdot 2^r \\otimes R = n \\cdot G<br \/>\n$$<br \/>\n\u5176\u4e2d<\/p>\n<ul>\n<li>n\u662f\u6574\u6570, \u4ee3\u8868\u6574\u9664<\/li>\n<li>\u5de6\u4fa7\u4ee3\u8868\u5c06D\u5de6\u79fbr\u4f4d, \u7136\u540e\u8865R(EDC)<\/li>\n<\/ul>\n<p>\u53ef\u4ee5\u89e3\u5f97<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223182738761.png\" alt=\"image-20241223182738761\" style=\"zoom:40%;\" \/><\/p>\n<p>\u5373, \u53d1\u9001\u65b9\u9700\u8981\u5c06\u53d1\u9001\u7684\u6570\u636eD<\/p>\n<ol>\n<li>\u8865r\u4e2a0<\/li>\n<li>\u9664G, \u53d6\u4f59\u6570R<\/li>\n<li>\u62fc\u63a5D-R<\/li>\n<\/ol>\n<p>\u63a5\u6536\u65b9\u5bf9\u6536\u5230\u7684\u6570\u636eM\u53ea\u9700 <\/p>\n<ol>\n<li>\u9664G\u68c0\u67e5\u6574\u9664 <\/li>\n<\/ol>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223183724203.png\" alt=\"image-20241223183724203\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223183954216.png\" alt=\"image-20241223183954216\" style=\"zoom:33%;\" \/><\/p>\n<p>CRC\u53ef\u4ee5\u68c0\u6d4b\u51fa\u6240\u67091bit, \u6240\u67092bit, \u6240\u6709\u957f\u5ea6&lt;=r\u7684\u9519\u8bef<\/p>\n<h2>6.3 \u591a\u8def\u8bbf\u95ee\u534f\u8bae<\/h2>\n<p>\u70b9\u5bf9\u70b9<\/p>\n<ul>\n<li>\u62e8\u53f7\u4e0a\u7f51<\/li>\n<\/ul>\n<p>\u591a\u70b9\u8fde\u63a5(\u5171\u4eab\u94fe\u8def\u6216\u8005\u5a92\u4f53)<\/p>\n<ul>\n<li>\u65e9\u671f\u4ee5\u592a\u7f51, HFC\u4e0a\u884c\u94fe\u8def, 802.11\u65e0\u7ebf\u5c40\u57df\u7f51<\/li>\n<\/ul>\n<blockquote>\n<p>\u65e9\u671f\u7684\u4ee5\u592a\u7f51\u4e2d, \u6bcf\u4e2a\u6570\u636e\u5305\u90fd\u662f\u53d1\u7ed9\u6574\u4e2a\u7f51\u7edc\u7684, \u4e3b\u673a\u901a\u8fc7MAC\u5730\u5740\u5224\u65ad\u662f\u5426\u662f\u53d1\u7ed9\u81ea\u5df1<\/p>\n<\/blockquote>\n<p>\u591a\u70b9\u8fde\u63a5\u7684\u7f51\u7edc\u4e5f\u53eb\u5e7f\u64ad\u5f0f\u7684\u7f51\u7edc, \u5728\u8fd9\u6837\u7684\u7f51\u7edc\u4e2d, \u5b58\u5728\u4e00\u79cd\u51b2\u7a81: \u591a\u4e2a\u7ad9\u70b9\u540c\u65f6\u62a2\u5360\u4f20\u8f93\u4ecb\u8d28, \u5bfc\u81f4\u4fe1\u606f\u91cd\u53e0\u5931\u6548<\/p>\n<p>\u9700\u8981\u5206\u5e03\u5f0f\u7684\u7b97\u6cd5\u51b3\u5b9a\u4e00\u4e2a\u8282\u70b9\u5728\u4f55\u65f6\u53ef\u4ee5\u4f7f\u7528\u8fd9\u6761\u5171\u4eab\u4fe1\u9053, \u8fd9\u5c31\u662fMAC\u95ee\u9898, \u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236\u95ee\u9898<\/p>\n<p>\u7531\u4e8e\u4fe1\u9053\u662f\u552f\u4e00\u7684, \u5173\u4e8e\u4fe1\u9053\u7684\u63a7\u5236\u4fe1\u606f, \u534f\u5546\u8fc7\u7a0b, \u4e5f\u53ea\u80fd\u5728\u4fe1\u9053\u672c\u8eab\u4e0a\u4f20\u8f93<\/p>\n<blockquote>\n<p>\u540d\u6b21\u89e3\u91ca: <\/p>\n<p>MAC, Media Access Control, \u5a92\u4f53\u8bbf\u95ee\u63a7\u5236<\/p>\n<p>MAP, Media Access Protocol, \u5a92\u4f53\u8bbf\u95ee\u534f\u8bae<\/p>\n<p>\u4e0a\u9762\u662f\u4ece\u7b97\u6cd5\u89d2\u5ea6\u8bf4, \u4e0b\u9762\u662f\u5b9e\u73b0\u89d2\u5ea6, \u5dee\u4e0d\u591a\u662f\u4e00\u4e2a\u610f\u601d, \u5f88\u591a\u5730\u65b9\u90fd\u80fd\u6df7\u7528<\/p>\n<\/blockquote>\n<h3>\u7406\u60f3\u7684\u591a\u8def\u8bbf\u95ee\u534f\u8bae<\/h3>\n<ul>\n<li>\u5f53\u4e00\u4e2a\u8282\u70b9\u8981\u53d1\u9001, \u53ef\u4ee5\u4ee5R\u7684\u901f\u7387\u53d1\u9001<\/li>\n<li>\u6863M\u4e2a\u8282\u70b9\u8981\u53d1\u9001, \u5219\u6bcf\u4e2a\u5e73\u5747\u53d1\u9001\u901f\u7387\u4f4dR\/M<\/li>\n<li>\u5b8c\u5168\u5206\u5e03\u5f0f\u7684: \u4e0d\u9700\u8981\u4e00\u4e2a\u8282\u70b9\u6765\u534f\u8c03<\/li>\n<li>\u7b80\u5355<\/li>\n<\/ul>\n<h3>MAC\u534f\u8bae: \u5206\u7c7b<\/h3>\n<p>\u603b\u7684\u6765\u8bf4\u67093\u5927\u7c7b<\/p>\n<ul>\n<li>\n<p>\u6309\u4fe1\u9053\u5212\u5206<\/p>\n<ul>\n<li>\u6309\u7167\u65f6\u95f4, \u9891\u7387<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u968f\u673a\u8bbf\u95ee<\/p>\n<ul>\n<li>\u968f\u673a\u4f7f\u7528\u4fe1\u9053, \u5141\u8bb8\u78b0\u649e, \u4f46\u9700\u8981\u89c4\u5b9a\u78b0\u649e\u6062\u590d<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u4f9d\u6b21\u8f6e\u6d41<\/p>\n<ul>\n<li>\u5b8c\u5168\u5206\u5e03\u7684: \u5229\u7528\u4ee4\u724c<\/li>\n<li>\u4e0d\u5b8c\u5168\u5206\u5e03\u7684: \u4e00\u4e2a\u4e3b\u673a\u8f6e\u6d41\u95ee\u8be2<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>\u4fe1\u9053\u5212\u5206MAC\u534f\u8bae: TDMA<\/h3>\n<p>\u65f6\u5206\u591a\u8def\u590d\u7528, TDMA: Time Division Multiple Access<\/p>\n<p>\u6309\u7167\u65f6\u949f\u5468\u671f, \u8f6e\u6d41\u4f7f\u7528\u4fe1\u9053, \u4e0d\u4f7f\u7528\u5219\u6d6a\u8d39\u65f6\u95f4<\/p>\n<h3>\u4fe1\u9053\u5212\u5206MAC\u534f\u8bae: FDMA<\/h3>\n<p>\u9891\u5206\u591a\u8def\u590d\u7528, F: Frequency<\/p>\n<p>\u6bcf\u4e2a\u7ad9\u70b9\u6709\u81ea\u5df1\u7684\u9891\u6bb5, \u4e0d\u4f7f\u7528\u5219\u6d6a\u8d39\u9891\u6bb5<\/p>\n<h3>\u7801\u5206\u591a\u8def\u8bbf\u95ee: CDMA<\/h3>\n<p>\u7801\u5206\u591a\u8def\u590d\u7528, C: Code<\/p>\n<ul>\n<li>\n<p>\u6240\u6709\u7ad9\u70b9\u540c\u65f6\u5728\u6574\u4e2a\u4ecb\u8d28\u4e0a\u4f20\u8f93, \u901a\u8fc7\u7f16\u7801\u539f\u7406\u533a\u5206<\/p>\n<\/li>\n<li>\n<p>\u5b8c\u5168\u65e0\u51b2\u7a81<\/p>\n<\/li>\n<li>\n<p>\u5047\u5b9a\u4fe1\u53f7\u540c\u6b65\u5f88\u597d, \u5e76\u53ef\u4ee5\u7ebf\u6027\u53e0\u52a0<\/p>\n<\/li>\n<\/ul>\n<h3>\u968f\u673a\u5b58\u53d6\u534f\u8bae: Random Access<\/h3>\n<p>\u5f53\u8282\u70b9\u6709\u6570\u636e\u9700\u8981\u53d1\u9001\u65f6, \u4e0d\u505a\u534f\u8c03, \u76f4\u63a5\u53d1\u9001<\/p>\n<p>\u534f\u8bae\u5141\u8bb8\u51b2\u7a81, \u5e76\u4e14\u8981\u89c4\u5b9a<\/p>\n<ul>\n<li>\u5982\u4f55\u68c0\u6d4b\u51b2\u7a81<\/li>\n<li>\u5982\u4f55\u5904\u7406\u51b2\u7a81(\u91cd\u4f20\u7b49)<\/li>\n<\/ul>\n<p>\u968f\u673aMAC\u534f\u8bae\u6709: <\/p>\n<ul>\n<li>\u65f6\u9699ALOHA, ALOHA<\/li>\n<li><strong>CSMA\/CD, CSMA\/CA<\/strong><\/li>\n<\/ul>\n<p>\u73b0\u4ee3\u4ee5\u592a\u7f51\u91c7\u7528CSMA\/CD, \u65e0\u7ebf\u5c40\u57df\u7f51802.11\u91c7\u7528CSMA\/CA<\/p>\n<p>CS:\u8f7d\u6ce2\u4fa6\u542c MA: \u591a\u8def\u8bbf\u95ee CD: \u51b2\u7a81\u68c0\u6d4b CA: \u51b2\u7a81\u907f\u514d<\/p>\n<h4>\u65f6\u9699ALOHA<\/h4>\n<p>\u5c06\u65f6\u95f4\u5206\u6210\u4e86\u4e00\u6bb5\u6bb5\u7b49\u957f\u7684\u65f6\u9699(\u6216\u8005\u53eb\u65f6\u69fd)<\/p>\n<h3>\u91cd\u8981\u5047\u8bbe<\/h3>\n<ul>\n<li>\u6240\u6709\u5e27\u7b49\u957f, \u6bcf\u4e2a\u65f6\u9699\u53d1\u9001\u4e00\u5e27<\/li>\n<li>\u8282\u70b9\u5728\u65f6\u9699\u5f00\u59cb\u8282\u70b9\u53d1\u9001<\/li>\n<li>\u8282\u70b9\u7684\u65f6\u949f\u540c\u6b65<\/li>\n<li>\u51b2\u7a81\u53ef\u4ee5\u88ab\u6240\u6709\u7ad9\u70b9\u68c0\u6d4b\u5230<\/li>\n<\/ul>\n<p>\u5f53\u4e00\u4e2a\u8282\u70b9\u83b7\u5f97\u4e86\u65b0\u7684\u5e27, \u4ece\u4e0b\u4e00\u4e2a\u65f6\u9699\u7684\u5f00\u59cb\u53d1\u9001, \u5982\u679c\u51b2\u7a81\u4e86, \u53ef\u4ee5\u89c2\u6d4b\u80fd\u91cf\u5e45\u5ea6\u6765\u68c0\u6d4b\u51b2\u7a81. \u5982\u679c\u51b2\u7a81\u4e86, \u4e0b\u4e2a\u65f6\u9699\u4ee5\u6982\u7387p\u53d1<\/p>\n<p>\u5982\u679c\u4e0d\u5de7\u53c8\u78b0\u4e86, \u90a3\u5c31\u7ee7\u7eed\u7b49\u5230\u4e0b\u4e2a\u65f6\u9699, \u4ee5\u6982\u7387p\u53d1<\/p>\n<p>\u6ca1\u6709\u4e00\u4e2a\u5ef6\u8fdf\u4e0a\u9650, \u7406\u8bba\u4e0a\u5b58\u5728\u4e00\u76f4\u53d1\u4e0d\u51fa\u53bb\u7684\u53ef\u80fd<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223202609086.png\" alt=\"image-20241223202609086\" style=\"zoom:33%;\" \/><\/p>\n<h4>\u7eafALOHA(\u975e\u65f6\u9699ALOHA)<\/h4>\n<p>\u975e\u5e38\u81ea\u7531: \u6709\u6570\u636e\u5e27\u5c31\u76f4\u63a5\u53d1<\/p>\n<p>\u78b0\u649e\u6982\u7387\u6bd4\u65f6\u9699ALOHA\u5927\u5f88\u591a(\u5927\u4e00\u500d)<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223202912202.png\" alt=\"image-20241223202912202\" style=\"zoom:33%;\" \/><\/p>\n<h3>CSMA: \u8f7d\u6ce2\u4fa6\u542c, \u591a\u8def\u8bbf\u95ee<\/h3>\n<p>\u5728\u53d1\u9001\u5e27\u4e4b\u524d\u5148\u4fa6\u542c\u4fe1\u9053, \u5982\u679c\u5fd9\u5c31\u63a8\u8fdf\u81ea\u5df1\u7684\u53d1\u9001: \u4e0d\u4e3b\u52a8\u6253\u65ad\u522b\u4eba\u7684\u4f20\u8f93<\/p>\n<p>\u51b2\u7a81\u4ecd\u6709\u53ef\u80fd\u53d1\u751f: \u4fa6\u542c\u6709\u5ef6\u8fdf, \u4e5f\u8bb8\u522b\u4eba\u5df2\u7ecf\u5f00\u59cb\u53d1\u9001\u4e86, \u53ea\u662f\u6ca1\u6709\u4f20\u64ad\u5230\u672c\u5730<\/p>\n<p>\u4f20\u64ad\u5ef6\u8fdf\u51b3\u5b9a\u4e86\u51b2\u7a81\u6982\u7387: \u7269\u7406\u8ddd\u79bb\u8d8a\u8fdc, \u5ef6\u8fdf\u8d8a\u5927\u8d8a\u5bb9\u6613\u51b2\u7a81<\/p>\n<h3>CSMA\/CD: \u51b2\u7a81\u68c0\u6d4b<\/h3>\n<ul>\n<li>\n<p>\u5982\u679c\u76d1\u6d4b\u5230\u51b2\u7a81, \u5219\u7acb\u5373\u4e2d\u65ad\u901a\u4fe1<\/p>\n<\/li>\n<li>\n<p>\u51b2\u7a81\u68c0\u6d4b\u6280\u672f\u5728\u6709\u5f62\u4ecb\u8d28\u4e2d\u5bb9\u6613\u5b9e\u73b0<\/p>\n<ul>\n<li>\u68c0\u6d4b\u4fe1\u53f7\u5f3a\u5ea6, \u6bd4\u8f83\u4f20\u8f93\u4e0e\u63a5\u6536<\/li>\n<li>\u5468\u671f\u7684\u8fc70\u70b9\u68c0\u6d4b<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223203911362.png\" alt=\"image-20241223203911362\" style=\"zoom:33%;\" \/><\/p>\n<p>\u4ee5\u592a\u7f51\u7684CSMA\/CD\u9664\u4e86\u4e0a\u8ff0\u5916, \u8fd8\u6709\u4ee5\u4e0b\u89c4\u5219<\/p>\n<ul>\n<li>\u4fa6\u6d4b\u5230\u51b2\u7a81\u653e\u5f03\u901a\u4fe1\u65f6, \u53d1\u9001JAM\u4fe1\u53f7(\u5f3a\u5316\u51b2\u7a81, \u901a\u77e5\u6240\u6709\u8282\u70b9)<\/li>\n<li>\u653e\u5f03\u4e4b\u540e, \u8fdb\u5165\u4e8c\u8fdb\u5236\u6307\u6570\u9000\u907f\u72b6\u6001<\/li>\n<\/ul>\n<blockquote>\n<p>CSMA\/CD\u7b97\u6cd5\u4e3b\u8981\u5e94\u7528\u4e8e\u65e9\u671f\u7684\u4ee5\u592a\u7f51, \u4f7f\u7528\u96c6\u7ebf\u5668(\u5171\u4eab\u4f20\u8f93\u4ecb\u8d28)\u4e0a\u7f51\u7684\u60c5\u666f<\/p>\n<p>\u5728\u73b0\u4ee3\u4ee5\u592a\u7f51\u4e2d, \u4ea4\u6362\u673a\u4ee3\u66ff\u4e86\u96c6\u7ebf\u5668, \u8ba9\u7f51\u7edc\u652f\u6301\u7aef\u5230\u7aef\u7684\u5168\u53cc\u5de5\u901a\u8baf, \u8fd9\u4f7f\u5f97CSMA\/CD\u7b97\u6cd5\u51e0\u4e4e\u9000\u51fa\u4e86\u5386\u53f2\u821e\u53f0<\/p>\n<p>CSMA\/CD\u7b97\u6cd5\u88ab\u8bbe\u8ba1\u89e3\u51b3\u534a\u53cc\u5de5\u901a\u8baf\u95ee\u9898, \u73b0\u4ee3\u4ee5\u592a\u7f51\u5219\u662f\u5168\u53cc\u5de5\u7684<\/p>\n<p>\u66f4\u591a\u8865\u5145: \u867d\u7136\u7f51\u5361\u7684\u7269\u7406\u5730\u5740(MAC\u5730\u5740, Media Access Control Addr.)\u540d\u5b57\u4e2d\u6709MAC, \u4f46\u662f\u56e0\u4e3a\u4ea4\u6362\u673a\u7684\u666e\u53ca, \u4f5c\u7528\u5df2\u7ecf\u548c\u63a7\u5236\u8bbf\u95ee\u5173\u7cfb\u4e0d\u5927\u4e86<\/p>\n<p>\u5728\u65e9\u671f\u4ee5\u592a\u7f51\u4e2d, MAC\u548cCSMA\/CD\u534f\u8bae\u5173\u7cfb\u5bc6\u5207, \u5355\u5728\u4eca\u5929, MAC\u5730\u5740\u66f4\u591a\u7684\u662f\u4f5c\u4e3a\u7f51\u5361\u6807\u8bc6\u4f7f\u7528<\/p>\n<\/blockquote>\n<h3>CSMA\/CA: \u51b2\u7a81\u907f\u514d<\/h3>\n<p>CSMA\/CA\u4e3b\u8981\u5e94\u7528\u4e8e\u65e0\u7ebf\u7f51\u7edc\u901a\u8baf\u4e2d, \u8fd9\u91cc\u63a2\u8ba8\u7684\u662f\u6709\u57fa\u7840\u8bbe\u65bd\u7684WLAN<\/p>\n<blockquote>\n<p>\u540d\u6b21\u89e3\u91ca: <\/p>\n<p>WLAN, Wireless Local Area Network, \u65e0\u7ebf\u5c40\u57df\u7f51<\/p>\n<p>LAN, (\u6709\u7ebf)\u5c40\u57df\u7f51<\/p>\n<\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223205142441.png\" alt=\"image-20241223205142441\" style=\"zoom:33%;\" \/><\/p>\n<p>\u65e0\u7ebf\u7f51\u7edc\u4e2d\u5f88\u96be\u505a\u51b2\u7a81\u68c0\u6d4b: \u4fe1\u53f7\u968f\u8ddd\u79bb\u8870\u51cf\u8fc7\u5feb<\/p>\n<p>IEEE 802.11: CSMA\/CA\u7684\u5b9e\u4f8b<\/p>\n<ul>\n<li>\u53d1\u4e4b\u524d\u4fa6\u542c, \u5982\u679c\u4fe1\u9053\u5fd9\u5219\u4e0d\u53d1<\/li>\n<li>\u4e00\u65e6\u5f00\u59cb\u53d1\u9001, \u4e00\u80a1\u8111\u53d1\u9001\u5b8c, \u4e0d\u505a\u51b2\u7a81\u68c0\u6d4b(\u6ca1\u6cd5\u505a)<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223205816117.png\" alt=\"image-20241223205816117\" style=\"zoom:50%;\" \/><\/p>\n<p>\u4e0a\u56fe\u4e2d\u63cf\u8ff0\u8fd9\u6837\u7684\u60c5\u666f: <\/p>\n<ul>\n<li>A2B, C2B<\/li>\n<li>AC\u4e4b\u95f4\u4fe1\u53f7\u5c4f\u969c, \u4e92\u76f8\u65e0\u6cd5\u77e5\u9053<\/li>\n<li>AC\u68c0\u6d4b\u4e0d\u5230\u51b2\u7a81, \u4f46\u5b9e\u9645\u4e0aB\u9644\u8fd1\u4e25\u91cd\u51b2\u7a81<\/li>\n<\/ul>\n<p>\u8fd9\u8bf4\u660e\u5728WLAN\u4e2d, \u4e3b\u89c2\u7684\u4e0d\u51b2\u7a81\u4e0d\u80fd\u8ba4\u4e3a\u4f20\u8f93\u6210\u529f, \u5e76\u4e14\u8fdb\u4e00\u6b65\u8bba\u8bc1\u4e86WLAN\u65e0\u6cd5\u505aCD<\/p>\n<ul>\n<li>\u800c\u5728LAN\u4e2d, \u4e3b\u89c2\u4e0d\u51b2\u7a81\u53ef\u4ee5\u8ba4\u4e3a\u662f\u4f20\u8f93\u6210\u529f<\/li>\n<\/ul>\n<p>802.11\u53d1\u9001\u65b9<\/p>\n<p>\u5982\u679c\u6709\u4fe1\u606f\u8981\u53d1\u9001, \u76d1\u542c\u4fe1\u9053<\/p>\n<ul>\n<li>\n<p>\u5982\u679c\u4fe1\u9053\u7a7a\u95f2\u4e86DIFS\u65f6\u95f4, \u76f4\u63a5\u53d1\u9001<\/p>\n<\/li>\n<li>\n<p>\u53cd\u4e4b\u5982\u679c\u4fe1\u9053\u5fd9, \u5219\u751f\u6210\u4e00\u4e2a\u968f\u673a\u7684\u56de\u9000\u503cT, \u8fd9\u4e2aT\u4f1a\u5728\u4fe1\u9053\u7a7a\u95f2\u7684\u65f6\u5019\u9012\u51cf(\u4fe1\u9053\u5fd9\u65f6\u4e0d\u53d8)<\/p>\n<\/li>\n<li>\n<p>T=0\u65f6(\u53ea\u53ef\u80fd\u53d1\u751f\u5728\u4fe1\u9053\u7a7a\u95f2), \u53d1\u9001\u6574\u4e2a\u5e27, \u5982\u679c\u6536\u4e0d\u5230ACK, \u589e\u52a0\u56de\u9000\u503cT, \u7ee7\u7eed\u7b49\u5f85<\/p>\n<\/li>\n<\/ul>\n<p>802.11\u63a5\u6536\u65b9<\/p>\n<p>\u5982\u679c\u5e27\u6b63\u786e, \u4e14\u4fe1\u9053\u7a7a\u95f2SIFS\u540e, \u56de\u590dACK, SIFS &lt; DIFS, \u4f53\u73b0\u4e86ACK\u7684\u4f18\u5148\u7ea7\u8f83\u9ad8<\/p>\n<blockquote>\n<p>WLAN\u4e2d\u56e0\u4e3a\u65e0\u6cd5CD, \u9020\u6210\u5f88\u591a\u95ee\u9898, \u5176\u4e2d\u6700\u4e3b\u8981\u7684\u5c31\u662f\u53d1\u9001\u7684\u62a5\u6587\u4e0d\u786e\u5b9a\u6210\u529f, \u56e0\u6b64\u624d\u9700\u8981ACK, \u800cLAN\u4e0d\u9700\u8981ACK<\/p>\n<p>\u6ce8\u610f\u4e4b\u524d\u63d0\u5230\u7684, \u94fe\u8def\u5c42\u534f\u8bae\u662f\u90e8\u5206\u53ef\u9760\u7684(\u6709ACK\u7684), LAN\u4e0d\u9700\u8981ACK, \u4f46WLAN\u9700\u8981<\/p>\n<\/blockquote>\n<p>IEEE 802.11 MAC\u534f\u8bae\u65e0\u6cd5\u5b8c\u5168\u907f\u514d\u51b2\u7a81<\/p>\n<ul>\n<li>\u8282\u70b9\u88ab\u9690\u85cf<\/li>\n<li>\u9009\u62e9\u4e86\u975e\u5e38\u8fd1\u7684\u56de\u9000\u503c<\/li>\n<\/ul>\n<h2>6.4 LANs<\/h2>\n<h3>MAC\u5730\u5740 &amp; ARP<\/h3>\n<p>32bit\u7684IPv4\u5730\u5740<\/p>\n<ul>\n<li>\u7f51\u7edc\u5c42\u5730\u5740<\/li>\n<li>\u8d1f\u8d23\u6570\u636e\u62a5\u4f20\u8f93\u5230\u5f53\u524d\u5b50\u7f51\n<ul>\n<li>\u5373\u524dn-1\u8df3: \u7f51\u7edc\u53f7<\/li>\n<li>\u6700\u540e\u4e00\u8df3: \u4e3b\u673a\u53f7<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>48bit\u7684MAC\u5730\u5740\u662f\u5728\u4e00\u4e2a\u7f51\u7edc\u5185\u90e8\u6807\u8bc6\u552f\u4e00\u8282\u70b9\u7684\u5de5\u5177. \u7f51\u5361\u4e0d\u8ba4\u8bc6IP\u5730\u5740, \u53ea\u8ba4\u8bc6MAC\u5730\u5740<\/p>\n<p>ARP\u534f\u8bae\u8d1f\u8d23IP\u5730\u5740\u5230MAC\u5730\u5740\u7684\u8f6c\u6362<\/p>\n<ul>\n<li>IP\u5730\u5740\u662f\u5206\u5c42\u7684, \u8fd8\u6d89\u53ca\u8def\u7531\u6c47\u96c6\u6280\u672f<\/li>\n<li>MAC\u5730\u5740\u662f\u5e73\u9762\u7684, \u6bcf\u4e2a\u7f51\u7edc\u5185\u552f\u4e00<\/li>\n<\/ul>\n<blockquote>\n<p>MAC\u5730\u5740\u51fa\u573a\u56fa\u5316, \u5168\u7403\u552f\u4e00<\/p>\n<p>\u5b9e\u9645\u4e0a, \u5f88\u591aOS\u53ef\u4ee5\u6682\u65f6\u8986\u76d6(\u9690\u85cf)\u771f\u5b9eMAC\u5730\u5740, \u5b50\u7f51\u5185\u4e0d\u51b2\u7a81\u5373\u53ef<\/p>\n<p>\u4e00\u4e2a\u7269\u7406\u63a5\u53e3\u53ef\u4ee5\u7ed1\u5b9a\u591a\u4e2aIP\u5730\u5740(\u522b\u540d, \u591a\u64ad\u7b49), \u4f46\u662f\u4e00\u822c\u53ea\u6709\u4e00\u4e2aMAC\u5730\u5740<\/p>\n<\/blockquote>\n<p>MAC\u5730\u5740\u662f\u94fe\u8def\u5c42\u5730\u5740, \u548cIP\u5730\u5740\u5206\u79bb\u6709\u5f88\u591a\u597d\u5904, \u5176\u4e2d\u4e4b\u4e00\u5c31\u662f\u4e0b\u5c42\u4e0d\u5e94\u8be5\u5173\u5fc3\u4e0a\u5c42\u7684\u4fe1\u606f<\/p>\n<h3>ARP: Addr. Resolution Protocol<\/h3>\n<p>\u95ee\u9898: \u5df2\u77e5B\u7684IP\u5730\u5740, \u5982\u4f55\u8f6c\u6362\u4e3aMAC\u5730\u5740?<\/p>\n<ul>\n<li>\u5982\u679c\u672c\u5730\u7684ARP\u8868\u4e2d\u6709\u7f13\u5b58\u7ed3\u679c, \u5c31\u76f4\u63a5\u8f6c\u6362<\/li>\n<li>\u5982\u679c\u6ca1\u6709, \u5219\u5728\u672c\u5730\u7f51\u7edc\u6cdb\u6d2a\u8be2\u95ee<\/li>\n<li>\u76ee\u6807\u4e3b\u673a\u6536\u5230\u8be2\u95ee\u540e, \u56de\u590d\u81ea\u5df1\u7684MAC\u5730\u5740<\/li>\n<\/ul>\n<p>ARP\u662f\u5373\u63d2\u5373\u7528\u7684, \u8fd9\u662f\u56e0\u4e3a\u5bf9\u5e94\u5173\u7cfb\u5f88\u5bb9\u6613\u53d8\u5316<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223223046335.png\" alt=\"image-20241223223046335\" style=\"zoom:33%;\" \/><\/p>\n<p>\u5206\u7ec4\u5168\u7a0b\u6e90IP, \u76ee\u6807IP\u90fd\u4e0d\u53d8, \u4f46\u662f\u6bcf\u4e00\u8df3\u7684\u6e90MAC, \u76ee\u6807MAC\u90fd\u5728\u53d8<\/p>\n<h3>\u4ee5\u592a\u7f51: \u6700\u6d41\u884c\u7684LAN\u6280\u672f<\/h3>\n<p>\u65e9\u671f\u4ee5\u592a\u7f51\u9700\u8981\u7528\u5230CSMA\/CD\u534f\u8bae: \u540c\u8f74\u7535\u7f06<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223223208782.png\" alt=\"image-20241223223208782\" style=\"zoom:33%;\" \/><br \/>\n<img decoding=\"async\" src=\"https:\/\/pic.cirno.fun\/sssn-blog-pics\/image-20241223223457708.png\" alt=\"image-20241223223457708\" style=\"zoom:33%;\" \/><\/p>\n<p>HUB<\/p>\n<ul>\n<li>\n<p>\u7269\u7406\u5c42\u8bbe\u5907, \u53ea\u63d0\u4f9b\u94fe\u63a5, \u94fe\u8def\u901f\u7387\u5fc5\u987b\u4e00\u6837<\/p>\n<\/li>\n<li>\n<p>\u7269\u7406\u4e0a\u662f\u661f\u5f62\u7684, \u903b\u8f91\u4e0a\u8fd8\u662f\u603b\u7ebf, \u6cdb\u6d2a\u6240\u6709\u6570\u636e<\/p>\n<\/li>\n<li>\n<p>\u6536\u53d1\u901f\u7387\u4e00\u81f4, \u6ca1\u6709\u7f13\u5b58<\/p>\n<\/li>\n<li>\n<p>\u6240\u6709\u8282\u70b9\u5904\u5728\u4e00\u4e2a\u78b0\u649e\u57df, \u9700\u8981CSMA\/CD<\/p>\n<\/li>\n<\/ul>\n<p>\u4ea4\u6362\u673a<\/p>\n<ul>\n<li>\n<p>\u94fe\u8def\u5c42\u8bbe\u5907, \u6839\u636e\u5e27\u5934\u9009\u62e9\u6027\u8f6c<\/p>\n<\/li>\n<li>\n<p>\u81ea\u5b66\u4e60\u7684\u4ea4\u6362\u8868, \u65e0\u9700\u914d\u7f6e, \u53ef\u4ee5\u7ea7\u8054<\/p>\n<ul>\n<li>\u540c\u6837\u4f1a\u9009\u62e9\u6027\u7684drop\u548c\u6cdb\u6d2a<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u6709MAC\u5730\u5740, \u6ca1\u6709IP\u5730\u5740<\/p>\n<\/li>\n<li>\n<p>\u53ef\u4ee5\u8ba4\u4e3a\u5728\u8f6c\u53d1\u7684\u77ac\u95f4\u5f62\u6210\u4e86\u901a\u8def<\/p>\n<\/li>\n<li>\n<p>\u6b64\u65f6\u4e0d\u592a\u9700\u8981CSMA\/CD\u4e86(\u8c61\u5f81\u6027\u7684\u505a, \u4f46\u662f\u5f31\u5316\u4e86)<\/p>\n<\/li>\n<li>\n<p>\u751f\u6210\u6811\u7b97\u6cd5, \u540c\u65f6\u95f4\u4e0d\u80fd\u6210\u73af<\/p>\n<\/li>\n<\/ul>\n<p>\u4ee5\u592a\u7f51\u63d0\u4f9b\u7684\u662f\u65e0\u8fde\u63a5, \u4e0d\u53ef\u9760\u7684\u670d\u52a1<\/p>\n<ul>\n<li>LAN\u7684\u51fa\u9519\u7387\u6bd4\u8f83\u4f4e, CRC\u51fa\u9519\u5c31\u4e22\u6389<\/li>\n<\/ul>\n<h3>802.3 \u4ee5\u592a\u7f51\u7684\u6807\u51c6: \u94fe\u8def\u5c42\u4e0e\u7269\u7406\u5c42<\/h3>\n<p>\u4ee5\u592a\u7f51\u7684\u6807\u51c6\u5f88\u591a, \u5bf9\u5e94\u4e0d\u540c\u7684\u7269\u7406\u5a92\u4ecb<\/p>\n<ul>\n<li>\u5149\u7ea4, \u540c\u8f74\u7535\u7f06, \u53cc\u7ede\u7ebf, &#8230;<\/li>\n<\/ul>\n<p>\u8fd9\u4e9b\u6807\u51c6\u4e0b\u7edf\u4e00\u4e0d\u53d8\u7684\u6709<\/p>\n<ul>\n<li>MAC\u534f\u8bae<\/li>\n<li>\u5e27\u7ed3\u6784<\/li>\n<li>CSMA\/CD(\u5c3d\u7ba1\u5df2\u7ecf\u7528\u4e0d\u4e0a)<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u8ba1\u7b97\u673a\u7f51\u7edc(\u81ea\u9876\u5411\u4e0b\u65b9\u6cd5) \u7b2c7\u7248 James F.Kurose\u7b49 \u672c\u7b14\u8bb0\u4e3b\u8981\u5185 [&#8230;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[],"class_list":["post-815","post","type-post","status-publish","format-standard","hentry","category-30"],"_links":{"self":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts\/815","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=815"}],"version-history":[{"count":2,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts\/815\/revisions"}],"predecessor-version":[{"id":817,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=\/wp\/v2\/posts\/815\/revisions\/817"}],"wp:attachment":[{"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=815"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=815"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.sssn.tech\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=815"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}