{"id":1184,"date":"2021-12-30T00:11:59","date_gmt":"2021-12-29T16:11:59","guid":{"rendered":"https:\/\/blog.cauchyschwarz.com\/?p=1184"},"modified":"2021-12-30T00:12:07","modified_gmt":"2021-12-29T16:12:07","slug":"tcp%e4%b8%8equic","status":"publish","type":"post","link":"https:\/\/blog.cauchyschwarz.com\/?p=1184","title":{"rendered":"TCP\u4e0eQUIC"},"content":{"rendered":"\n<p>\u5728<a href=\"https:\/\/xie.infoq.cn\/article\/6bba9dd34fb49b7adacb4aacd\">\u8fd9\u7bc7\u6587\u7ae0<\/a>\u91cc\u94fe\u63a5\u4e86\u4e00\u4e2aQUIC\u7684\u90a3\u4e9b\u4e8b\u7cfb\u5217\u6587\u7ae0\uff0c\u70b9\u51fb\u94fe\u63a5\uff0c\u53ef\u4ee5\u770b\u5230\u4f5c\u8005\u7684\u4e00\u4e2a<a href=\"https:\/\/mp.weixin.qq.com\/mp\/appmsgalbum?__biz=MzA3Nzk2NTY1MA==&amp;action=getalbum&amp;album_id=1325436211703627777&amp;subscene=159&amp;subscene=190&amp;scenenote=https%3A%2F%2Fmp.weixin.qq.com%2Fs%3F__biz%3DMzA3Nzk2NTY1MA%3D%3D%26mid%3D2649163932%26idx%3D4%26sn%3Dd53c4ab268eb0f620708b088bff1dd3e%26chksm%3D875a58a1b02dd1b7ce375dbd9cd19ee31fe7519beb5419f573376f85a682003d6544b25c74f8%26cur_album_id%3D1325436211703627777%26scene%3D190%23rd&amp;nolastread=1#wechat_redirect\">TCP\/IP\u7cfb\u5217\u6587\u7ae0<\/a>\uff0c\u5206\u522b\u8bb2\u4e86TCP\u548cQUIC\u7684\u4e00\u4e9b\u4e1c\u897f\uff0e<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 ez-toc-wrap-right counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-69e0ad97bd8b9\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-69e0ad97bd8b9\" checked aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#TCP\" >TCP<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#1_MSS\" >1. MSS<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#2_MTU\" >2. MTU<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#3_%E5%9B%9B%E6%AC%A1%E6%8C%A5%E6%89%8B\" >3. \u56db\u6b21\u6325\u624b<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#4_%E4%B8%89%E6%AC%A1%E6%8F%A1%E6%89%8B\" >4. \u4e09\u6b21\u63e1\u624b<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#5_TCP%E6%8A%A5%E6%96%87%E6%A0%BC%E5%BC%8F%E8%A7%A3%E6%9E%90\" >5. TCP\u62a5\u6587\u683c\u5f0f\u89e3\u6790<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#6_%E5%BF%AB%E9%80%9F%E9%87%8D%E4%BC%A0\" >6. \u5feb\u901f\u91cd\u4f20<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#7_SACK\" >7.&nbsp;SACK<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#8_D-SACK\" >8.&nbsp;D-SACK<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#9_%E6%BB%91%E5%8A%A8%E7%AA%97%E5%8F%A3\" >9. \u6ed1\u52a8\u7a97\u53e3<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#10_%E6%85%A2%E5%90%AF%E5%8A%A8\" >10. \u6162\u542f\u52a8<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#11_%E5%9C%A8%E9%80%94%E5%AD%97%E8%8A%82%E6%95%B0\" >11. \u5728\u9014\u5b57\u8282\u6570<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#12_%E6%8B%A5%E5%A1%9E%E9%81%BF%E5%85%8D\" >12. \u62e5\u585e\u907f\u514d<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#13_%E5%BF%AB%E9%80%9F%E6%81%A2%E5%A4%8D\" >13. \u5feb\u901f\u6062\u590d<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#14_Early_Retransmit\" >14.&nbsp;Early Retransmit<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#15_TLPTail_Loss_Probe\" >15. TLP(Tail Loss Probe)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#TCP_FAST_OPEN\" >TCP FAST OPEN<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#16_%E5%B8%A7%E7%B1%BB%E5%9E%8B\" >16. \u5e27\u7c7b\u578b<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#14_NAT\" >14. NAT<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#QUIC_1%E5%8C%85%E7%B1%BB%E5%9E%8B%E5%92%8C%E6%A0%BC%E5%BC%8F\" >QUIC 1.\u5305\u7c7b\u578b\u548c\u683c\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#QUIC_2%E5%B8%A7%E7%B1%BB%E5%9E%8B%E5%92%8C%E6%A0%BC%E5%BC%8F\" >QUIC 2.\u5e27\u7c7b\u578b\u548c\u683c\u5f0f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#QUIC_30RTT\" >QUIC 3.0RTT<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=1184\/#QUIC_4%E6%8B%A5%E5%A1%9E%E6%8E%A7%E5%88%B6\" >QUIC 4.\u62e5\u585e\u63a7\u5236<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\" id=\"tcp-1\"><span class=\"ez-toc-section\" id=\"TCP\"><\/span>TCP<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"1-mss-1\"><span class=\"ez-toc-section\" id=\"1_MSS\"><\/span>1. MSS<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Maximum Segment Size\uff0c\u6307TCP\u5305\u91cc\u6240\u542b\u6570\u636e\u7684\u6700\u5927\u957f\u5ea6(\u4e0d\u5305\u62ecTCP\u5934)\uff0e\u5728syn\/ack\u91cc\u534f\u5546\uff0c\u4e00\u822c\u4e3a1460(\u52a0\u4e0a20\u5b57\u8282TCP\u5934\uff0c20\u5b57\u8282IP\u5934\u6b63\u597d\u662f\u6570\u636e\u94fe\u8def\u5c42MTU)\uff0e<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"2-mtu-1\"><span class=\"ez-toc-section\" id=\"2_MTU\"><\/span>2. MTU<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u5e38\u8bf4\u7684MTU\u662f\u6570\u636e\u94fe\u8def\u5c42\u7684MTU\uff0c\u6570\u636e\u94fe\u8def\u5c42\u91cc\u6bcf\u4e2a\u5305\u91cc\u7684\u6570\u636e\u90e8\u5206\u957f\u5ea6\u7684MTU\u4e00\u822c\u4e3a1500\uff0c\u6570\u636e\u94fe\u8def\u5c42\u672c\u8eab\u8fd8\u67096\u4e2a\u5b57\u8282\u7684\u6e90\u5730\u5740\uff0c6\u4e2a\u5b57\u8282\u7684\u76ee\u7684\u5730\u5740\uff0c2\u4e2a\u5b57\u8282\u7684\u7c7b\u578b\uff0c\u4ee5\u53ca4\u4e2a\u5b57\u8282\u7684CRC\u6821\u9a8c\uff0e\u6240\u4ee5\u6570\u636e\u94fe\u8def\u5c42\u4e00\u4e2a\u5305\u91cc\u7684\u6570\u636e\u5728\u8fbe\u52301500\u5b57\u8282\u7684\u60c5\u51b5\u4e0b\uff0c\u6574\u4e2a\u5305\u7684\u5927\u5c0f\u4e3a1500+6+6+2+4=1518\u5b57\u8282\uff0e<br>MTU\u6700\u5c0f\u503c\u662f46(64-6-6-2-4)\uff0c\u8fd9\u662f\u7531CSMA\/CD\u673a\u5236\u68c0\u6d4b\u78b0\u649e\u6240\u51b3\u5b9a\u7684\uff0c\u5982\u679c\u4e00\u4e2a\u6570\u636e\u94fe\u8def\u5c42\u5305\u91cc\u7684\u6570\u636e\u6ca1\u6709\u8fbe\u523046\u4e2a\u5b57\u8282\uff0c\u9700\u8981\u8fdb\u884c\u88650\uff0e<br>\u63a2\u6d4bMTU\u662f\u901a\u8fc7\u7ed9IP\u5305\u8bbe\u7f6eDF(\u4e0d\u8981\u5206\u7247)\u6807\u5fd7\u6765\u5b9e\u73b0\u7684\uff0c\u8fd9\u6837\u5f53IP\u5305\u5927\u4e8eMTU\u65f6\u6574\u4e2a\u5305\u5c31\u4f1a\u88ab\u4e22\u5f03\u6389\uff0e<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"3-e59b9be6aca1e68ca5e6898b-1\"><span class=\"ez-toc-section\" id=\"3_%E5%9B%9B%E6%AC%A1%E6%8C%A5%E6%89%8B\"><\/span>3. \u56db\u6b21\u6325\u624b<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" width=\"750\" height=\"619\" class=\"wp-image-1185\" style=\"width: 750px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_close.webp\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_close.webp 745w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_close-300x248.webp 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_close-670x553.webp 670w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/>\u00a0<\/p>\n\n\n\n<p>\u4e00\u822c\u9762\u8bd5\u4e2d\u4f1a\u7ecf\u5e38\u95ee\u5230\u8fd9\u4e2aTIME_WAIT\u72b6\u6001\u7684\u610f\u4e49\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u9632\u6b62\u6700\u540e\u4e00\u4e2aack\u4e22\u5931\uff0c\u5bf9\u7aef\u9700\u8981\u91cd\u4f20fin\uff1b<\/li><li>\u6709\u8db3\u591f\u7684\u65f6\u95f4\u8ba9\u8fd9\u4e2a\u8fde\u63a5\u4e0d\u4f1a\u8ddf\u540e\u9762\u7684\u8fde\u63a5\u6df7\u5728\u4e00\u8d77\uff1b<\/li><\/ol>\n\n\n\n<p>\u5bf9\u8d1f\u8f7d\u9ad8\u7684\u670d\u52a1\u5668\uff0c\u53ef\u80fd\u51fa\u73b0TIME_WAIT\u72b6\u6001\u7684\u5957\u63a5\u5b57\u5f88\u591a\uff0c\u89e3\u51b3\u65b9\u6cd5\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>tcp_tw_reuse(\u9700\u8981\u540c\u65f6\u8bbe\u7f6etcp_timestamps=1)<\/li><li>tcp_tw_recycle \u8bbe\u7f6e\u8fd9\u4e24\u4e2a\u53c2\u6570\u53ef\u80fd\u5bfc\u81f4\u5efa\u8fde\u51fa\u95ee\u9898\uff0e<\/li><\/ol>\n\n\n\n<p>\u4e24\u7aef\u51e0\u4e4e\u540c\u65f6close\u7684\u60c5\u51b5\uff1a\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"750\" height=\"600\" class=\"wp-image-1186\" style=\"width: 750px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_simul_close.webp\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_simul_close.webp 666w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_simul_close-300x240.webp 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"4-e4b889e6aca1e68fa1e6898b-1\"><span class=\"ez-toc-section\" id=\"4_%E4%B8%89%E6%AC%A1%E6%8F%A1%E6%89%8B\"><\/span>4. \u4e09\u6b21\u63e1\u624b<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>\u5e8f\u5217\u53f7\u7684\u521d\u59cb\u503c\u4e0d\u80fd\u662f\u786c\u7f16\u7801\u7684\uff0c\u800c\u662f\u548c\u5185\u90e8\u7684\u4e00\u4e2a\u865a\u62df\u59cb\u7ec8\u7ed1\u5b9a\u7684\uff1b<\/li><li>\u5efa\u7acb\u8fde\u63a5\u65f6\uff0c\u5982\u679c\u5ba2\u6237\u7aef\u4e00\u76f4\u4e0d\u56de\u6700\u540e\u4e00\u4e2aack\uff0c\u90a3\u4e48\u670d\u52a1\u5668\u7aef\u5c31\u4f1a\u4e0d\u65ad\u91cd\u4f20\u81ea\u5df1\u7684\u90a3\u4e2asyn+ack\u5305\uff0c\u5e76\u4e14\u4f1a\u91cd\u4f205\u6b21\uff0c\u9700\u8981\u603b\u51711s+2s+4s+8s+16s+32s=63s\u624d\u4f1a\u653e\u5f03\u8fd9\u4e2a\u8fd9\u4e2aTCP\u8fde\u63a5\uff1b<\/li><li>syn flood\u653b\u51fb\uff1a\u5982\u679c\u5ba2\u6237\u7aef\u6076\u610f\u7684\u4e0d\u505c\u5730\u53d1syn\u5305\uff0c\u5e76\u4e14\u4e0d\u56de\u6700\u540e\u4e00\u4e2aack\uff0c\u90a3\u4e48\u5c31\u4f1a\u5f88\u5feb\u8017\u5c3d\u670d\u52a1\u5668\u7684syn\u8fde\u63a5\u961f\u5217\uff1b\u5bfc\u81f4\u670d\u52a1\u5668\u4e0d\u80fd\u4e3a\u6b63\u5e38\u7528\u6237\u7684\u8fde\u63a5\u670d\u52a1\uff1b<\/li><li>syn_cookie\uff1a\u4e3a\u4e86\u5e94\u5bf9syn flood\u653b\u51fb\uff0clinux\u5728syn\u8fde\u63a5\u961f\u5217\u6ee1\u7684\u65f6\u5019\u53ef\u4ee5\u4f7f\u7528syn_cookie\u673a\u5236\uff0c\u5bf9\u4e8e\u5ba2\u6237\u7aef\u53d1\u8fc7\u6765\u7684syn\uff0c\u5229\u7528\u6e90\u5730\u5740\u7aef\u53e3\u3001\u76ee\u6807\u5730\u5740\u7aef\u53e3\u548c\u65f6\u95f4\u6233\u751f\u6210\u4e00\u4e2acookie\u53d1\u56de\u5ba2\u6237\u7aef\uff0c\u5e76\u4e14\u8fd9\u4e2a\u65f6\u5019\u670d\u52a1\u7aef\u4e0d\u4f1a\u4e3a\u8fd9\u4e2a\u65b0\u5efa\u7684\u534a\u8fde\u63a5\u5b58\u4efb\u4f55\u4e1c\u897f(\u4e5f\u5c31\u907f\u514d\u4e86\u8017\u5c3d\u670d\u52a1\u5668\u7684\u8d44\u6e90)\uff0c\u5ba2\u6237\u7aef\u53d1\u6700\u540e\u4e00\u4e2aack\u65f6\u9700\u8981\u628a\u8fd9\u4e2acookie\u5e26\u4e0a\uff0c\u670d\u52a1\u5668\u6839\u636ecookie\u6062\u590d\u51fa\u6e90\u5730\u5740\u7aef\u53e3\u3001\u76ee\u6807\u5730\u5740\u7aef\u53e3\u548c\u65f6\u95f4\u6233\uff0c\u5e76\u6839\u636e\u8fd9\u4e9b\u4fe1\u606f\u5efa\u7acb\u5b8c\u6574\u7684TCP\u8fde\u63a5\uff0e<\/li><li>syn_cookie\u7684\u7f3a\u70b9\uff1acookie\u91cc\u4fdd\u5b58\u7684\u4e1c\u897f\u6709\u9650\uff0c\u4f1a\u4e22\u6389\u5ba2\u6237\u7aef\u5efa\u8fde\u65f6\u5e26\u7684\u4e00\u4e9bTCP\u9009\u9879\uff0e<\/li><\/ol>\n\n\n\n<p>\u540c\u65f6\u5efa\u7acb\u8fde\u63a5\u7684\u60c5\u5f62\uff1a\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"750\" height=\"255\" class=\"wp-image-1187\" style=\"width: 750px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_simul_open.webp\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_simul_open.webp 447w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_simul_open-300x102.webp 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"5-tcpe68aa5e69687e6a0bce5bc8fe8a7a3e69e90-1\"><span class=\"ez-toc-section\" id=\"5_TCP%E6%8A%A5%E6%96%87%E6%A0%BC%E5%BC%8F%E8%A7%A3%E6%9E%90\"><\/span>5. TCP\u62a5\u6587\u683c\u5f0f\u89e3\u6790<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"564\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_header.webp\" alt=\"\" class=\"wp-image-1188\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_header.webp 800w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_header-300x212.webp 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_header-768x541.webp 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp_header-670x472.webp 670w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/figure>\n\n\n\n<ol class=\"wp-block-list\"><li>1-2\u5b57\u8282\uff1a\u6e90\u7aef\u53e3<\/li><li>3-4\u5b57\u8282\uff1a\u76ee\u7684\u7aef\u53e3<\/li><li>5-8\u5b57\u8282\uff1a\u5e8f\u53f7\uff0c\u5e8f\u53f7\u7528\u6765\u6807\u8bc6\u4eceTCP\u53d1\u7aef\u5411TCP\u6536\u7aef\u53d1\u9001\u7684\u6570\u636e\u5b57\u8282\u6d41\uff0c\u5230\u8fbe2^32\uff0d1\u540e\u53c8\u4ece0\u5f00\u59cb<\/li><li>9-12\u5b57\u8282\uff1a\u786e\u8ba4\u53f7\uff1b\u786e\u8ba4\u53f7\u662f\u53d1\u9001\u786e\u8ba4\u7684\u4e00\u7aef\u6240\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u5e8f\u53f7<\/li><li>13-14\u5b57\u8282\uff1a\u9996\u5148\u662f4bit\u7684\u9996\u90e8\u957f\u5ea6\uff08\u9996\u90e8\u957f\u5ea6\u7ed9\u51fa\u9996\u90e8\u4e2d32 bit\u5b57\u7684\u6570\u76ee\u3002\u9700\u8981\u8fd9\u4e2a\u503c\u662f\u56e0\u4e3a\u4efb\u9009\u5b57\u6bb5\u7684\u957f\u5ea6\u662f\u53ef\u53d8\u7684\uff0cTCP\u6700\u591a\u670960\u5b57\u8282\u7684\u9996\u90e8\u3002\u5982\u679c\u6ca1\u6709\u4efb\u9009\u5b57\u6bb5\uff0c\u6b63\u5e38\u7684\u957f\u5ea6\u662f20\u5b57\u8282\uff09\uff1b\u968f\u540e\u662f6bit\u7684\u4fdd\u7559\u5b57\u6bb5\uff1b\u6700\u540e\u662f6bit\u7684Flags\uff0c\u542b\u4e49\u5982\u4e0b\uff1a<ol><li>\u7d27\u6025URG\uff1a\u5f53URG=1\u65f6\uff0c\u8868\u793a\u62a5\u6587\u6bb5\u4e2d\u6709\u7d27\u6025\u6570\u636e\uff0c\u5e94\u5c3d\u5feb\u4f20\u9001<\/li><li>\u786e\u8ba4\u6bd4\u7279ACK\uff1aACK = 1\u65f6\u4ee3\u8868\u8fd9\u662f\u4e00\u4e2a\u786e\u8ba4\u7684TCP\u5305\uff0c\u53d6\u503c0\u5219\u4e0d\u662f\u786e\u8ba4\u5305<\/li><li>\u63a8\u9001\u6bd4\u7279PSH\uff1a\u5f53\u53d1\u9001\u7aefPSH=1\u65f6\uff0c\u63a5\u6536\u7aef\u5c3d\u5feb\u7684\u4ea4\u4ed8\u7ed9\u5e94\u7528\u8fdb\u7a0b<\/li><li>\u590d\u4f4d\u6bd4\u7279\uff08RST\uff09\uff1a\u5f53RST=1\u65f6\uff0c\u8868\u660eTCP\u8fde\u63a5\u4e2d\u51fa\u73b0\u4e25\u91cd\u5dee\u9519\uff0c\u5fc5\u987b\u91ca\u653e\u8fde\u63a5\uff0c\u518d\u91cd\u65b0\u5efa\u7acb\u8fde\u63a5<\/li><li>\u540c\u6b65\u6bd4\u7279SYN\uff1a\u5728\u5efa\u7acb\u8fde\u63a5\u662f\u7528\u6765\u540c\u6b65\u5e8f\u53f7\u3002SYN=1\uff0c ACK=0\u8868\u793a\u4e00\u4e2a\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\u6bb5\uff0cSYN=1\uff0cACK=1\u8868\u793a\u540c\u610f\u5efa\u7acb\u8fde\u63a5<\/li><li>\u7ec8\u6b62\u6bd4\u7279FIN\uff1aFIN=1\u65f6\uff0c\u8868\u660e\u6b64\u62a5\u6587\u6bb5\u7684\u53d1\u9001\u7aef\u7684\u6570\u636e\u5df2\u7ecf\u53d1\u9001\u5b8c\u6bd5\uff0c\u5e76\u8981\u6c42\u91ca\u653e\u4f20\u8f93\u8fde\u63a5<\/li><\/ol><\/li><li>15-16\u5b57\u8282\uff1a\u6211\u65b9\u7a97\u53e3\u4e0a\u9650\uff0c\u7528\u4e8e\u63a7\u5236\u5bf9\u65b9\u53d1\u9001\u7684\u6570\u636e\u91cf\uff1b<\/li><li>17-18\u5b57\u8282\uff1a\u6821\u9a8c\u548c\uff0c\u8be5\u5b57\u6bb5\u68c0\u9a8c\u7684\u8303\u56f4\u5305\u62ec\u9996\u90e8\u548c\u6570\u636e\u8fd9\u4e24\u90e8\u5206\u3002\u7531\u53d1\u7aef\u8ba1\u7b97\u548c\u5b58\u50a8\uff0c\u5e76\u7531\u6536\u7aef\u8fdb\u884c\u9a8c\u8bc1\u3002<\/li><li>19-20\u5b57\u8282\uff1a\u7d27\u6025\u6307\u9488\uff0c\u7d27\u6025\u6307\u9488\u5728URG=1\u65f6\u624d\u6709\u6548\uff0c\u5b83\u6307\u51fa\u672c\u62a5\u6587\u6bb5\u4e2d\u7684\u7d27\u6025\u6570\u636e\u7684\u5b57\u8282\u6570\u3002<\/li><li>21-60\u5b57\u8282\uff1a\u53ef\u9009\uff08\u957f\u5ea6\u53ef\u53d8\uff09\uff0c\u53ef\u4ee5\u6709\uff0c\u4e5f\u53ef\u4ee5\u65e0\u3002<\/li><\/ol>\n\n\n\n<p>\u53ef\u4ee5\u53d1\u73b0TCP\u5934\u91cc\u6ca1\u6709\u6807\u660epayload\u7684\u957f\u5ea6\uff0c\u8fd9\u4e2a\u957f\u5ea6\u9700\u8981\u901a\u8fc7IP\u5305\u7684\u957f\u5ea6\u51cf\u53bbIP\u5934\u518d\u51cf\u53bbTCP\u5934\u957f\u5ea6\u8ba1\u7b97\u5f97\u5230\uff0e<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"6-e5bfabe9809fe9878de4bca0-1\"><span class=\"ez-toc-section\" id=\"6_%E5%BF%AB%E9%80%9F%E9%87%8D%E4%BC%A0\"><\/span>6. \u5feb\u901f\u91cd\u4f20<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u7531\u4e8eTCP\u4f7f\u7528\u7684\u662f\u7d2f\u79ef\u786e\u8ba4\u7684\u65b9\u5f0f\uff0c\u5728\u4e22\u5931\u5e8f\u53f7\u4e3an\u7684\u5305\uff0c\u4e14\u63a5\u6536\u5230\u5e8f\u53f7\u5927\u4e8en\u7684\u5305\u65f6\uff0c\u63a5\u6536\u7aef\u4f1a\u53d1ack n\uff0c\u90a3\u4e48\u53d1\u9001\u7aef\u5728\u8fde\u7eed\u91cd\u590d\u6536\u52303\u4e2aack n(\u603b\u5171\u6536\u52304\u6b21ack n)\u540e\uff0c\u5c31\u53ef\u4ee5\u4e0d\u7528\u7b49\u5f85\u5e8f\u53f7\u4e3an\u7684\u5305\u7684\u8d85\u65f6\u91cd\u4f20\u5b9a\u65f6\u5668\uff0c\u800c\u662f\u76f4\u63a5\u91cd\u4f20\u5e8f\u53f7\u4e3an\u7684\u5305\u4e86\uff0e\u5feb\u901f\u91cd\u4f20\u7b97\u6cd5\u4ecd\u7136\u6709\u4e00\u4e2a\u95ee\u9898\uff0c\u90a3\u5c31\u662f\u4ecd\u7136\u9700\u8981\u91cd\u4f20\u5e8f\u53f7\u4e3an\u7684\u5305\u4e4b\u540e\u7684\u5305\uff0c\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u9700\u8981SACK.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"7-sack-1\"><span class=\"ez-toc-section\" id=\"7_SACK\"><\/span>7.&nbsp;<a href=\"https:\/\/datatracker.ietf.org\/doc\/html\/rfc2018\">SACK<\/a><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u9700\u8981\u5728\u63e1\u624b\u65f6\u901a\u8fc7TCP Sack-Permitted Option\u9009\u9879\u786e\u8ba4\u53cc\u65b9\u90fd\u652f\u6301SACK\uff0c\u63e1\u624b\u65f6\u5360\u7528\u4e24\u4e2a\u5b57\u8282\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">       +---------+---------+\n       | Kind=4  | Length=2|\n       +---------+---------+\n<\/code><\/pre>\n\n\n\n<p>\u5728\u4f20\u8f93\u8fc7\u7a0b\u4e2d\uff0c\u51fa\u73b0\u4e22\u5305\u65f6\uff0c\u901a\u8fc7SACK option\u6307\u51fa\u6536\u5230\u7684\u4e22\u5931\u5305\u540e\u9762\u6536\u5230\u7684\u5305\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">                         +--------+--------+\n                         | Kind=5 | Length |\n       +--------+--------+--------+--------+\n       |      Left Edge of 1st Block       |\n       +--------+--------+--------+--------+\n       |      Right Edge of 1st Block      |\n       +--------+--------+--------+--------+\n       |                                   |\n       \/            . . .                  \/\n       |                                   |\n       +--------+--------+--------+--------+\n       |      Left Edge of nth Block       |\n       +--------+--------+--------+--------+\n       |      Right Edge of nth Block      |\n       +--------+--------+--------+--------+\n<\/code><\/pre>\n\n\n\n<ol class=\"wp-block-list\"><li>\u6bcf\u4e2ablock\u786e\u8ba4\u6536\u5230\u7684\u8303\u56f4\u662f<code>[Left Edge, Right Edge)<\/code>\uff0e\u5360\u7528\u7684TCP\u5934\u5b57\u8282\u6570\u4e3a2+8*k\uff0ck\u4e3ablock\u6570\uff0c\u6240\u4ee5\u6bcf\u4e2atcp\u5305\u91cc\u6700\u591a\u5305\u542b\uff14\u4e2ablock\uff0c\u800c\u4e14\u5982\u679c\u6253\u5f00\u4e86timestamp\u9009\u9879(\u5360\u752810\u4e2a\u5b57\u8282)\uff0c\u90a3\u4e48\u5305\u542b\u7684block\u6570\u53c8\u8981\u51cf\u5c11\uff0c\u6700\u591a\u4e3a\uff13\uff0e<\/li><li>sack\u53ea\u80fd\u7b97\u662f\u4f18\u5316\u91cd\u4f20\u7684\u4e00\u79cd\u624b\u6bb5\uff0c\u771f\u6b63\u786e\u8ba4\u5305\u5230\u8fbe\u8fd8\u662f\u9700\u8981\u539f\u6765\u7684\u7d2f\u79ef\u786e\u8ba4ack\u5305\uff0c\u5373\u53d1\u9001\u7aef\u91cd\u4f20\u65f6\u53ef\u4ee5\u901a\u8fc7\u68c0\u67e5\u6570\u636e\u5305\u7684SACKed\u6807\u5fd7\uff0c\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u91cd\u4f20\uff0c\u4f46\u662f\u53ea\u6709\u5728\u6536\u5230\u7d2f\u8ba1\u786e\u8ba4\u5305\u540e\u624d\u53ef\u4ee5\u5c06\u8be5\u6570\u636e\u5305\u4ece\u91cd\u4f20\u961f\u5217\u91cc\u5220\u6389.<\/li><li>\u63a5\u6536\u65b9Reneging\uff1a\u63a5\u6536\u65b9\u53ef\u80fd\u51fa\u4e8e\u5185\u5b58\u4e0d\u8db3\u7b49\u60c5\u51b5\u5c06\u5df2\u7ecfSACK\u7684\u6570\u636e\u5305\u7ed9\u4e22\u6389\uff0c\u8fd9\u5c31\u662f\u4e0a\u9762\u7b2c\u4e8c\u70b9\u5fc5\u987b\u6536\u5230\u7d2f\u8ba1ACK\u624d\u80fd\u5c06\u6570\u636e\u5305\u4ece\u91cd\u4f20\u961f\u5217\u91cc\u5220\u9664\u7684\u539f\u56e0\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\u8fd9\u4e9b\u5df2\u7ecfSACK\u4f46\u662f\u88ab\u4e22\u6389\u7684\u6570\u636e\u8fd8\u662f\u53ef\u4ee5\u901a\u8fc7\u8d85\u65f6\u91cd\u4f20\u8fdb\u884c\u91cd\u4f20\uff0c\u4ece\u800c\u8fbe\u5230\u6570\u636e\u53ef\u9760\u4f20\u8f93\u7684\u76ee\u7684\uff0e<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"8-d-sack-1\"><span class=\"ez-toc-section\" id=\"8_D-SACK\"><\/span>8.&nbsp;<a href=\"https:\/\/datatracker.ietf.org\/doc\/html\/rfc2883\">D-SACK<\/a><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>SACK\u53ef\u4ee5\u5e2e\u52a9\u53d1\u9001\u7aef\u533a\u5206\u51fa\u5df2\u7ecf\u6536\u5230\u4e0d\u5fc5\u8981\u91cd\u4f20\u7684\u6570\u636e\u5305\uff0c\u5bf9SACK\u8fdb\u884c\u6269\u5c55\uff0c\u5f62\u6210D-SACK\uff0c\u53ef\u4ee5\u5e2e\u52a9\u53d1\u9001\u7aef\u533a\u5206\u51fa\u63a5\u6536\u7aef\u91cd\u590d\u6536\u5230\u7684\u5305\uff0e<br>D-SACK\u4ecd\u7136\u4f7f\u7528\u4e86SACK\u7684\u683c\u5f0f\uff0c\u53ea\u662f\u9700\u8981\u989d\u5916\u7684\u903b\u8f91\u5224\u65ad\u662f\u5426\u662fD-SACK\uff0e<br>D-SACK\u4f7f\u7528\u4e86SACK\u7684\u7b2c\u4e00\u4e2a\u6bb5\u6765\u505a\u6807\u5fd7\uff0c\u5982\u4f55\u5224\u65adD-SACK\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u5982\u679cSACK\u7684\u7b2c\u4e00\u4e2a\u6bb5\u7684\u8303\u56f4\u88abACK\u6240\u8986\u76d6\uff0c\u90a3\u4e48\u5c31\u662fD-SACK<\/li><li>\u5982\u679cSACK\u7684\u7b2c\u4e00\u4e2a\u6bb5\u7684\u8303\u56f4\u88abSACK\u7684\u7b2c\u4e8c\u4e2a\u6bb5\u8986\u76d6\uff0c\u90a3\u4e48\u5c31\u662fD-SACK<\/li><\/ol>\n\n\n\n<p>D-SACK\u7684\u89c4\u5219\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u7b2c\u4e00\u4e2ablock\u5c06\u5305\u542b\u91cd\u590d\u6536\u5230\u7684\u62a5\u6587\u6bb5\u7684\u5e8f\u53f7<\/li><li>\u8ddf\u5728D-SACK\u4e4b\u540e\u7684SACK\u5c06\u6309\u7167SACK\u7684\u65b9\u5f0f\u5de5\u4f5c<\/li><li>\u5982\u679c\u6709\u591a\u4e2a\u88ab\u91cd\u590d\u63a5\u6536\u7684\u62a5\u6587\u6bb5\uff0c\u5219D-SACK\u53ea\u5305\u542b\u5176\u4e2d\u7b2c\u4e00\u4e2a<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"9-e6bb91e58aa8e7aa97e58fa3-1\"><span class=\"ez-toc-section\" id=\"9_%E6%BB%91%E5%8A%A8%E7%AA%97%E5%8F%A3\"><\/span>9. \u6ed1\u52a8\u7a97\u53e3<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><strong>window scale\u9009\u9879<\/strong>\uff1akind=3\uff0c\u7528\u4e8e\u8bbe\u7f6e\u5927\u7684window size\uff0c\u6700\u7ec8\u7684window\u5927\u5c0f\u4e3awindow size value * window size scaling factor\uff0e<\/p>\n\n\n\n<p><strong>Zero Window<\/strong>&nbsp;\u63a5\u6536\u7a97\u53e3\u4e3a0\u540e\uff0c\u53d1\u9001\u7a97\u53e3\u4e0d\u80fd\u7ee7\u7eed\u53d1\u9001\u6570\u636e\uff0c\u8fd9\u65f6\u9700\u8981\u901a\u8fc7\u53e6\u5916\u7684\u65b9\u5f0f\u66f4\u65b0\u8fd9\u4e2a\u63a5\u6536\u7a97\u53e3\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u53d1\u9001\u7aef\u53d1\u9001Zero Window Probe\uff0c\u63a5\u6536\u7aefACK\u5176\u7a97\u53e3\u5927\u5c0f\uff0e\u53d1\u9001ZWP\u7684\u65f6\u95f4\u95f4\u9694\u4e3a[CFG_WIN_PROBE_MIN\uff0cCFG_WIN_PROBE_MAX]\uff0c\u5982\u679c3\u6b21\u8fc7\u540e\u8fd8\u662f0\u7684\u8bdd\uff0c\u6709\u7684TCP\u5b9e\u73b0\u5c31\u4f1a\u901a\u8fc7RST\u65ad\u5f00\u8fde\u63a5\u3002<\/li><li>\u5982\u679c\u63a5\u6536\u7aef\u6ed1\u52a8\u7a97\u53e3\u4e0d\u4e3a0\uff0c\u5219\u63a5\u6536\u7aef\u4e3b\u52a8\u53d1\u9001TCP Window Update\u6765\u66f4\u65b0\u53d1\u9001\u65b9\u7684\u6ed1\u52a8\u7a97\u53e3\uff0e<\/li><\/ol>\n\n\n\n<p><strong>Silly Window Syndrome<\/strong>&nbsp;\u5982\u679c\u63a5\u6536\u7aef\u6765\u4e0d\u53ca\u63a5\u6536RCV.WND\u4e2d\u7684\u6570\u636e\uff0c\u90a3\u4e48\u7a97\u53e3\u5c31\u4f1a\u8d8a\u6765\u8d8a\u5c0f\u76f4\u81f3\u4e3a0\uff0c\u5982\u679c\u63a5\u6536\u7aef\u521a\u521a\u817e\u51fa\u5f88\u5c0f\u7684\u7a7a\u95f4\u5c31\u544a\u77e5\u53d1\u9001\u7aef\uff0c\u90a3\u4e48\u53d1\u9001\u7aef\u5c31\u4f1a\u7ee7\u7eed\u53d1\u9001\u6570\u636e\uff0c\u8fd9\u79cd\u73b0\u8c61\u5c31\u53eb\u505aSilly Window Syndrome\uff08\u7cca\u6d82\u7a97\u53e3\u7efc\u5408\u5f81\uff09\u3002<br>\u8981\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u4e5f\u4e0d\u96be\uff0c\u5c31\u662f\u907f\u514d\u5bf9\u5c0f\u7684Window size\u505a\u51fa\u54cd\u5e94\uff0c\u76f4\u5230\u6709\u8db3\u591f\u5927\u7684window size\u518d\u54cd\u5e94\uff0c\u8fd9\u4e2a\u601d\u8def\u53ef\u4ee5\u540c\u65f6\u5b9e\u73b0\u5728\u53d1\u9001\u7aef\u548c\u63a5\u6536\u7aef\u4e24\u7aef\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u5982\u679c\u8fd9\u4e2a\u95ee\u9898\u662f\u7531\u63a5\u6536\u7aef\u5f15\u8d77\u7684\uff0c\u53ef\u4ee5\uff1a\u5982\u679c\u63a5\u6536\u7aef\u6536\u5230\u7684\u6570\u636e\u5bfc\u81f4Window size\u5c0f\u4e8e\u67d0\u4e2a\u503c\uff0c\u53ef\u4ee5\u76f4\u63a5Ack(0)\u56de\u590d\u53d1\u9001\u7aef\uff0c\u8fd9\u6837\u5c31\u628aWindow\u7ed9\u5173\u95ed\u4e86\uff0c\u53d1\u9001\u7aef\u5c31\u4e0d\u4f1a\u7ee7\u7eed\u53d1\u9001\u6570\u636e\u3002\u5f53\u63a5\u6536\u7aef\u5904\u7406\u4e86\u4e00\u4e9b\u6570\u636e\u540eWindows size \u5927\u4e8e\u7b49\u4e8e\u4e86MSS\uff0c\u6216\u8005\u63a5\u6536\u7aef\u7f13\u51b2\u533a\u6709\u4e00\u534a\u4e3a\u7a7a\uff0c\u901a\u77e5\u53d1\u9001\u7aef\u53ef\u4ee5\u7ee7\u7eed\u53d1\u9001\u6570\u636e\u3002<\/li><li>\u5982\u679c\u8fd9\u4e2a\u95ee\u9898\u662f\u7531\u53d1\u9001\u7aef\u5f15\u8d77\u7684\uff0c\u90a3\u4e48\u5c31\u4f1a\u4f7f\u7528\u8457\u540d\u7684 Nagle\u2019s \u7b97\u6cd5\uff0c\u8fd9\u4e2a\u7b97\u6cd5\u7684\u601d\u8def\u4e5f\u662f\u5ef6\u65f6\u5904\u7406\uff0c\u9700\u8981\u6ee1\u8db3\u5982\u4e0b\u4e24\u4e2a\u6761\u4ef6\uff1a<ol><li>\u8981\u7b49\u5230 Window size&gt;=MSS \u6216\u662f Data Size &gt;=MSS;<\/li><li>\u6536\u5230\u4e4b\u524d\u53d1\u9001\u6570\u636e\u7684Ack\uff0c\u624d\u4f1a\u53d1\u6570\u636e\uff0c\u5426\u5219\u5c31\u662f\u5728\u6512\u6570\u636e;<\/li><\/ol><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"10-e685a2e590afe58aa8-1\"><span class=\"ez-toc-section\" id=\"10_%E6%85%A2%E5%90%AF%E5%8A%A8\"><\/span>10. \u6162\u542f\u52a8<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4ec0\u4e48\u65f6\u5019\u7528\u6162\u542f\u52a8\u7b97\u6cd5<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u8fde\u63a5\u521a\u521a\u5efa\u7acb\u65f6<\/li><li>\u68c0\u6d4b\u5230\u4e22\u5305\u65f6<\/li><\/ol>\n\n\n\n<p>\u6162\u542f\u52a8\u7b97\u6cd5\u539f\u7406<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u8fde\u63a5\u5efa\u597d\u7684\u5f00\u59cb\u5148\u521d\u59cb\u5316CWS = 1\uff0c\u8868\u660e\u53ef\u4ee5\u4f20\u4e00\u4e2aMSS\u5927\u5c0f\u7684\u6570\u636e<\/li><li>\u6bcf\u5f53\u6536\u5230\u4e00\u4e2aACK\uff0cCWS++; \u5448\u7ebf\u6027\u4e0a\u5347<\/li><li>\u6bcf\u5f53\u8fc7\u4e86\u4e00\u4e2aRTT\uff0cCWS = CWS*2; \u5448\u6307\u6570\u8ba9\u5347<\/li><li>\u5f53CWS\u8d85\u8fc7\u4e00\u4e2a\u6781\u9650\u503cSSThresh\uff08Slow Start Threshold\uff09\u65f6\uff0c\u5c31\u4e0d\u5728\u6309\u7167\u4e0a\u8ff0\u7684\u589e\u957f\u65b9\u5f0f\u589e\u52a0\uff0c\u800c\u662f\u8fdb\u5165\u201c\u62e5\u585e\u907f\u514d\u201d<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"11-e59ca8e98094e5ad97e88a82e695b0-1\"><span class=\"ez-toc-section\" id=\"11_%E5%9C%A8%E9%80%94%E5%AD%97%E8%8A%82%E6%95%B0\"><\/span>11. \u5728\u9014\u5b57\u8282\u6570<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u5728\u9014\u5b57\u8282\u6570 = \u5df2\u53d1\u9001\u6570\u636e-\u5df2\u6536\u5230Ack\u7684\u6570\u636e = Seq + Len &#8211; Ack<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"12-e68ba5e5a19ee981bfe5858d-1\"><span class=\"ez-toc-section\" id=\"12_%E6%8B%A5%E5%A1%9E%E9%81%BF%E5%85%8D\"><\/span>12. \u62e5\u585e\u907f\u514d<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u6162\u542f\u52a8\u7b97\u6cd5\u7684\u62e5\u585e\u7a97\u53e3\u5927\u5c0fCWS\uff08Congestion Window Size \uff09\u6709\u4e2a\u4e0a\u9650\u503cSSThresh\uff08Slow Start Threshold\uff09\uff0c\u5f53CWS &gt;= SSThresh\u65f6\uff0c\u5c31\u4f1a\u8fdb\u5165\u201c\u62e5\u585e\u907f\u514d\u201d\u9636\u6bb5\u3002\u4e00\u822c\u6765\u8bf4SSThresh\u7684\u503c\u662f65535\u5b57\u8282\uff0c\u5f53CWS\u8fbe\u5230\u8fd9\u4e2a\u503c\u65f6\u540e\uff0cCWS\u7684\u66f4\u65b0\u7b97\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u6536\u5230\u4e00\u4e2aACK\u65f6\uff0cCWS = CWS + 1\/CWS<\/li><li>\u5f53\u6bcf\u8fc7\u4e00\u4e2aRTT\u65f6\uff0cCWS =CWS + 1<\/li><\/ol>\n\n\n\n<p>\u8fdb\u5165\u62e5\u585e\u907f\u514d\u9636\u6bb5\u540e\uff0c\u7f51\u7edc\u4f9d\u7136\u4f1a\u62e5\u585e\u3002\u5982\u679c\u8fdb\u5165\u62e5\u585e\u72b6\u6001\uff0c\u7f51\u7edc\u53d1\u751f\u4e22\u5305\uff0c\u90a3\u4e48\u6709\u4e24\u79cd\u5904\u7406\u673a\u5236\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u7b49\u5230RTO\u8d85\u65f6\uff0c\u91cd\u4f20\u6570\u636e\u5305<br>SSThresh\u53caCWS\u7684\u66f4\u65b0\u8fc7\u7a0b\u5982\u4e0b\uff1a<br>SSThresh = CWS \/ 2<br>CWS = 1<br>\u968f\u540e\u8fdb\u5165\u6162\u542f\u52a8\u8fc7\u7a0b<\/li><li>\u4f7f\u7528\u5feb\u901f\u91cd\u4f20\uff08Fast Retransmit\uff09\uff1a\u6536\u52303\u4e2aDuplicate ACK\u65f6\u5c31\u5f00\u542f\u91cd\u4f20<br>TCP Tahoe\u7684\u5b9e\u73b0\u548cRTO\u8d85\u65f6\u4e00\u6837\uff1b<br>TCP Reno\u7684\u5b9e\u73b0\u662f\uff1a<br>CWS = CWS \/2<br>SSThresh = CWS<br>\u8fdb\u5165\u5feb\u901f\u6062\u590d\u7b97\u6cd5<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"13-e5bfabe9809fe681a2e5a48d-1\"><span class=\"ez-toc-section\" id=\"13_%E5%BF%AB%E9%80%9F%E6%81%A2%E5%A4%8D\"><\/span>13. \u5feb\u901f\u6062\u590d<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>TCP RENO\u4e2d\u7684\u5feb\u901f\u6062\u590d\u7b97\u6cd5\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u542f\u52a8\u5feb\u901f\u91cd\u4f20<\/li><li>\u8bbe\u7f6eSSThresh = CWS\/2 \u4ee5\u53ca CWS = SSThresh + 3 * MSS.<\/li><li>\u4f7f\u7528\u62e5\u585e\u907f\u514d\u7b97\u6cd5\u66f4\u65b0CWS\u53caSSThresh :<br>1\uff09\u6536\u5230\u4e00\u4e2aAck\u65f6\uff0cCWS= CWS+ 1\/CWS<br>2\uff09\u5f53\u6bcf\u8fc7\u4e00\u4e2aRTT\u65f6\uff0cCWS= CWS+ 1<\/li><\/ol>\n\n\n\n<p>TCP New Reno\u7b97\u6cd5\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u5f53\u53d1\u9001\u7aef\u6536\u52303\u4e2a\u91cd\u590dAcks\uff0c\u8fdb\u5165\u5feb\u901f\u91cd\u4f20\u6a21\u5f0f\uff0c\u91cd\u4f20\u91cd\u590dAcks\u6307\u793a\u7684\u90a3\u4e2a\u5305\u3002\u5982\u679c\u53ea\u6709\u8fd9\u4e00\u4e2a\u5305\u4e22\u4e86\uff0c\u91cd\u4f20\u8fd9\u4e2a\u5305\u540e\u56de\u6765\u7684Ack\u4f1a\u628a\u6574\u4e2a\u5df2\u7ecf\u88ab\u53d1\u9001\u7aef\u4f20\u8f93\u51fa\u53bb\u7684\u6570\u636eAck\u56de\u6765\u3002\u5982\u679c\u6ca1\u6709\u7684\u8bdd\uff0c\u8bf4\u660e\u6709\u591a\u4e2a\u5305\u4e22\u4e86\uff0c\u6211\u4eec\u53eb\u8fd9\u4e2aACK \u4e3a Partial ACK\u3002<\/li><li>\u4e00\u65e6\u53d1\u9001\u7aef\u53d1\u73b0 Partial ACK \u51fa\u73b0\uff0c\u53d1\u9001\u7aef\u5c31\u53ef\u4ee5\u63a8\u7406\u51fa\u6765\u6709\u591a\u4e2a\u5305\u88ab\u4e22\u4e86\uff0c\u4e8e\u662f\u7ee7\u7eed\u91cd\u4f20\u6ed1\u52a8\u7a97\u53e3\u91cc\u672a\u88ab Ack \u7684\u7b2c\u4e00\u4e2a\u5305\u3002\u76f4\u5230\u518d\u4e5f\u6536\u4e0d\u5230\u4e86 Partial Ack\uff0c\u624d\u771f\u6b63\u7ed3\u675f\u5feb\u901f\u91cd\u4f20\u8fd9\u4e2a\u8fc7\u7a0b\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"750\" height=\"263\" class=\"wp-image-1189\" style=\"width: 750px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp-fast-recovery.webp\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp-fast-recovery.webp 900w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp-fast-recovery-300x105.webp 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp-fast-recovery-768x269.webp 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/tcp-fast-recovery-670x235.webp 670w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"14-early-retransmit-1\"><span class=\"ez-toc-section\" id=\"14_Early_Retransmit\"><\/span>14.&nbsp;<a href=\"http:\/\/perthcharles.github.io\/2015\/10\/31\/wiki-network-tcp-early-retrans\/\">Early Retransmit<\/a><span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u51fa\u73b0dupack\u4e0d\u591f\u7684\u60c5\u51b5\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>cwnd\u8f83\u5c0f<\/li><li>\u53d1\u9001\u7a97\u53e3\u91cc\u5927\u91cf\u7684\u6570\u636e\u5305\u90fd\u88ab\u4e22\u5931\u4e86<\/li><li>\u5728\u6570\u636e\u53d1\u9001\u7684\u5c3e\u7aef\u53d1\u751f\u4e22\u5305\u65f6<\/li><\/ol>\n\n\n\n<p>\u4f46\u662f\uff0c\u4e0a\u9762\u5404\u79cd\u6781\u7aef\u7684case\u6709\u5171\u540c\u7684\u7279\u70b9\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>\u65e0\u6cd5\u4ea7\u751f\u8db3\u591f\u7684dupack<\/li><li>\u6ca1\u6709\u65b0\u7684\u6570\u636e\u5305\u53ef\u4ee5\u53d1\u9001\u8fdb\u5165\u7f51\u7edc<\/li><\/ol>\n\n\n\n<p>Early Retransmit\u673a\u5236\u5c31\u662f\u5728\u5224\u65ad\u6761\u4ef6m\u548cn\u90fd\u6210\u7acb\u540e\uff0c\u9009\u62e9\u964d\u4f4e\u89e6\u53d1Fast Retransmit \u7684\u9608\u503c\uff0c\u6765\u907f\u514d\u53ea\u80fd\u901a\u8fc7RTO\u8d85\u65f6\u91cd\u4f20\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"15-tlptail-loss-probe-1\"><span class=\"ez-toc-section\" id=\"15_TLPTail_Loss_Probe\"><\/span>15. TLP(Tail Loss Probe)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>ER\u89e3\u51b3dupack\u4e0d\u591f\u7528\u7684\u60c5\u51b5\uff0cTLP\u89e3\u51b3\u6ca1\u6709dupack\u53ef\u7528\u7684\u60c5\u51b5\u3002<br>TLP\u7b97\u6cd5\u4f1a\u5728TCP\u8fd8\u662fOpen\u72b6\u6001\u7684\u65f6\u5019\uff0c\u8bbe\u7f6e\u4e00\u4e2aProbe TimeOut (PTO)\u3002 \u5f53\u94fe\u8def\u4e2d\u6709\u672a\u88ab\u786e\u8ba4\u7684\u6570\u636e\u5305\uff0c\u540c\u65f6\u5728PTO\u65f6\u95f4\u5185\u672a\u6536\u5230\u4efb\u4f55ACK\uff0c\u5219\u4f1a\u89e6\u53d1PTO \u8d85\u65f6\u5904\u7406\u673a\u5236\u3002 TLP\u4f1a\u9009\u62e9\u4f20\u8f93\u5e8f\u53f7\u6700\u5927\u7684\u4e00\u4e2a\u6570\u636e\u5305\u4f5c\u4e3atail loss probe\u5305\uff0c\u8fd9\u4e2a\u5e8f\u53f7\u6700\u5927\u7684\u5305\u53ef\u80fd\u662f \u4e00\u4e2a\u53ef\u4ee5\u53d1\u9001\u7684\u65b0\u7684\u6570\u636e\u5305\uff0c\u4e5f\u53ef\u80fd\u662f\u4e00\u4e2a\u91cd\u4f20\u5305\u3002 TLP\u901a\u8fc7\u8fd9\u6837\u4e00\u4e2atail loss probe\u5305\uff0c\u5982\u679c\u80fd\u591f\u6536\u5230\u76f8\u5e94\u7684ACK\uff0c\u5219\u4f1a\u89e6\u53d1FR\u673a\u5236\uff0c\u800c\u4e0d\u662fRTO\u673a\u5236\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"tcp-fast-open-1\"><span class=\"ez-toc-section\" id=\"TCP_FAST_OPEN\"><\/span>TCP FAST OPEN<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>TCP FAST OPEN\u9009\u9879\u53ef\u4ee5\u5141\u8bb8\u5728syn\u5305\u4e2d\u643a\u5e26\u5e94\u7528\u5c42\u6570\u636e\uff0c\u4ee5\u53ca\u5141\u8bb8\u670d\u52a1\u5668\u5728\u4e09\u6b21\u63e1\u624b\u5b8c\u6210\u524d\u5c06syn\u5305\u4e2d\u643a\u5e26\u7684\u6570\u636e\u8fd4\u56de\u7ed9\u5e94\u7528\u5c42\uff0e<br>\u5de5\u4f5c\u539f\u7406\uff1a\u7b2c\u4e00\u6b21\u8fde\u63a5\u65f6\u670d\u52a1\u5668\u4f1a\u8fd4\u56decookie\u7ed9\u5ba2\u6237\u7aef\uff0c\u5ba2\u6237\u7aef\u9700\u8981\u4fdd\u5b58\u8fd9\u4e2acookie\uff0c\u540e\u9762\u5ba2\u6237\u7aef\u5728\u91cd\u65b0\u8fde\u63a5\u65f6\u5e26\u4e0a\u8fd9\u4e2acookie\uff0c\u5e76\u4e14\u5728syn\u5305\u4e2d\u53ef\u4ee5\u643a\u5e26\u6570\u636e\uff0e<br>\u5f00\u542f\u65b9\u5f0f\uff1asysctl\u4fee\u6539net.ipv4.tcp_fast_open\uff0c\u8bbe\u7f6e\u7684\u503c\u9ed8\u8ba4\u4e3a\uff11\u7684\u8bdd\u53ea\u662f\u5141\u8bb8\u5ba2\u6237\u7aef\u5728syn\u5305\u4e2d\u643a\u5e26\u6570\u636e\uff0c\u56e0\u6b64\u5bf9\u4e8e\u670d\u52a1\u5668\u9700\u8981\u5c06\u8fd9\u4e2a\u503c\u6539\u4e3a3\uff0c\u4ee5\u6253\u5f00\u670d\u52a1\u5668\u7aef\u7684FAST OPEN\u9009\u9879\uff0c\u4ee5\u5141\u8bb8\u670d\u52a1\u5668\u5728\u4e09\u6b21\u63e1\u624b\u5b8c\u6210\u524d\u5c06\u63a5\u6536\u5230\u7684syn\u5305\u4e2d\u7684\u6570\u636e\u629b\u7ed9\u5e94\u7528\u5c42\uff0e<br>\u7f16\u7a0b\u6ce8\u610f\u70b9\uff1a\u5ba2\u6237\u7aef\u60f3\u8981\u5728syn\u5305\u91cc\u53d1\u9001\u6570\u636e\uff0c\u90a3\u5c31\u4e0d\u80fd\u4f7f\u7528connect\uff0c\u800c\u662f\u4f7f\u7528sendto,sendmsg\u76f4\u63a5\u53d1\u9001\u6570\u636e\uff0c\u800c\u4e14\u8981\u5e26\u4e0aTCP_FASTOPEN\u9009\u9879\uff0e\u670d\u52a1\u5668\u7aef\u9700\u8981\u901a\u8fc7setsockopt\u8bbe\u7f6e\u4e0bFASTOPEN\u9009\u9879\uff0c\u8bbe\u7f6eTFO\u961f\u5217\u957f\u5ea6\uff0e<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/bg2bkk.github.io\/post\/tcp_fast_open%E7%9A%84%E6%A6%82%E5%BF%B5%20%E4%BD%9C%E7%94%A8%E4%BB%A5%E5%8F%8A%E5%AE%9E%E7%8E%B0\/\">https:\/\/bg2bkk.github.io\/post\/tcp_fast_open\u7684\u6982\u5ff5 \u4f5c\u7528\u4ee5\u53ca\u5b9e\u73b0\/<\/a><\/li><li><a href=\"https:\/\/blog.csdn.net\/u014023993\/article\/details\/85928026\">https:\/\/blog.csdn.net\/u014023993\/article\/details\/85928026<\/a><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"16-e5b8a7e7b1bbe59e8b-1\"><span class=\"ez-toc-section\" id=\"16_%E5%B8%A7%E7%B1%BB%E5%9E%8B\"><\/span>16. \u5e27\u7c7b\u578b<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u666e\u901a\u5e27\u7c7b\u578b<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>PADDING<\/li><li>RST_STREAM<\/li><li>CONNECTION_CLOSE<\/li><li>GOAWAY<\/li><li>WINDOW_UPDATE<\/li><li>STOP_WAITING<\/li><li>PING \u7279\u6b8a\u5e27\u7c7b\u578b<\/li><li>STREAM<\/li><li>ACK<\/li><li>CONGESTIN_FEEDBACK<\/li><\/ul>\n\n\n\n<p><strong>ACK<\/strong>\u4e2d\u7684\u5e8f\u5217\u53f7\u4e3a\u8fc4\u4eca\u4e3a\u6b62\u89c2\u5bdf\u5230\u7684\u6700\u5927PacketNumber\uff0c\u968f\u540e\u662f\u4e22\u5931\u6570\u636e\u5305\u5217\u8868\u6216\u8005NACK\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"14-nat-1\"><span class=\"ez-toc-section\" id=\"14_NAT\"><\/span>14. NAT<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"quic-1e58c85e7b1bbe59e8be5928ce6a0bce5bc8f-1\"><span class=\"ez-toc-section\" id=\"QUIC_1%E5%8C%85%E7%B1%BB%E5%9E%8B%E5%92%8C%E6%A0%BC%E5%BC%8F\"><\/span>QUIC 1.\u5305\u7c7b\u578b\u548c\u683c\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u5982<a href=\"https:\/\/datatracker.ietf.org\/doc\/rfc9000\/\">RFC9000<\/a>\u6240\u8bf4\uff0c\u4e00\u4e2aQUIC\u5305\u91cc\u662f\u53ef\u4ee5\u5305\u542b\u4e0d\u540cstream\u7684frame\u7684\uff0c\u56e0\u6b64\u4e22\u4e00\u4e2a\u5305\u662f\u53ef\u80fd\u5bfc\u81f4\u8fd9\u4e2a\u5305\u91cc\u7684\u51e0\u4e2astream\u963b\u585e\u7684\uff0e\u5728\u5b9e\u73b0QUIC\u7684\u65f6\u5019\uff0c\u5e94\u8be5\u8ba9\u5c3d\u91cf\u5c11\u7684stream\u7684frame\u653e\u5728\u540c\u4e00\u4e2a\u5305\u91cc\uff1a<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>A sender sends one or more frames in a QUIC packet; see Section 12.4.<\/p><\/blockquote>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>A sender can minimize per-packet bandwidth and computational costs by including as many frames as possible in each QUIC packet. A sender MAY wait for a short period of time to collect multiple frames before sending a packet that is not maximally packed, to avoid sending out large numbers of small packets. An implementation MAY use knowledge about application sending behavior or heuristics to determine whether and for how long to wait. This waiting period is an implementation decision, and an implementation should be careful to delay conservatively, since any delay is likely to increase application- visible latency.<\/p><\/blockquote>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>Stream multiplexing is achieved by interleaving STREAM frames from multiple streams into one or more QUIC packets. A single QUIC packet can include multiple STREAM frames from one or more streams.<\/p><\/blockquote>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>One of the benefits of QUIC is avoidance of head-of-line blocking across multiple streams. When a packet loss occurs, only streams with data in that packet are blocked waiting for a retransmission to be received, while other streams can continue making progress. Note that when data from multiple streams is included in a single QUIC packet, loss of that packet blocks all those streams from making progress. Implementations are advised to include as few streams as necessary in outgoing packets without losing transmission efficiency to underfilled packets.<\/p><\/blockquote>\n\n\n\n<p>\u7279\u6b8aPacket:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u7248\u672c\u534f\u5546Packet<\/li><li>Public Reset Packet\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"750\" height=\"374\" class=\"wp-image-1190\" style=\"width: 750px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/QUIC-packet-format.webp\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/QUIC-packet-format.webp 651w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/QUIC-packet-format-300x150.webp 300w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/li><\/ul>\n\n\n\n<p>\u666e\u901aPacket:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>FEC Packet<\/li><li>Frame Packet<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"quic-2e5b8a7e7b1bbe59e8be5928ce6a0bce5bc8f-1\"><span class=\"ez-toc-section\" id=\"QUIC_2%E5%B8%A7%E7%B1%BB%E5%9E%8B%E5%92%8C%E6%A0%BC%E5%BC%8F\"><\/span>QUIC 2.\u5e27\u7c7b\u578b\u548c\u683c\u5f0f<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"quic-30rtt-1\"><span class=\"ez-toc-section\" id=\"QUIC_30RTT\"><\/span>QUIC 3.0RTT<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"quic-4e68ba5e5a19ee68ea7e588b6-1\"><span class=\"ez-toc-section\" id=\"QUIC_4%E6%8B%A5%E5%A1%9E%E6%8E%A7%E5%88%B6\"><\/span>QUIC 4.\u62e5\u585e\u63a7\u5236<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li>\u5355\u8c03\u9012\u589e\u7684Packet Number\uff0c\u53ef\u4ee5\u5e2e\u52a9\u533a\u5206\u91cd\u4f20\u5305\u548c\u975e\u91cd\u4f20\u5305\uff0c\u6bcf\u4e2aStream\u6709\u81ea\u5df1\u7684Offset\uff0e<\/li><li>\u4e0d\u5141\u8bb8 Reneging\uff1a\u534f\u8bae\u5c42\u9762\u4e0d\u5141\u8bb8\u4e22\u5f03\u5df2\u7ecfSACK\u7684\u5305\uff0c\u907f\u514dTCP\u90a3\u79cd\u63a5\u6536\u65b9\u4e22\u5f03SACK\u5305\u7684\u884c\u4e3a\uff0c\u9632\u6b62\u5e72\u6270\u91cd\u4f20\uff0e<\/li><li>\u66f4\u591a\u7684Ack Block\uff1aTCP\u5934\u7531\u4e8e\u957f\u5ea6\u7684\u9650\u5236(\u6700\u591a60\u5b57\u8282)\uff0cSACK\u6700\u591a\u5e264\u4e2aBlock\uff0cQuic Ack Frame \u53ef\u4ee5\u540c\u65f6\u63d0\u4f9b 256 \u4e2a Ack Block\uff0c\u5728\u4e22\u5305\u7387\u6bd4\u8f83\u9ad8\u7684\u7f51\u7edc\u4e0b\uff0c\u66f4\u591a\u7684 Sack Block \u53ef\u4ee5\u63d0\u5347\u7f51\u7edc\u7684\u6062\u590d\u901f\u5ea6\uff0c\u51cf\u5c11\u91cd\u4f20\u91cf\uff0e<\/li><li>QUIC\u8ba1\u7b97\u4e86Ack Delay(\u4ece\u6536\u5230\u6570\u636e\u5305\u5230Ack\u8be5\u6570\u636e\u5305\u7684delay)\uff0c\u8ba9RTT\u7684\u8ba1\u7b97\u66f4\u51c6\u786e.<\/li><\/ol>\n","protected":false},"excerpt":{"rendered":"<p>\u5728\u8fd9\u7bc7\u6587\u7ae0\u91cc\u94fe\u63a5\u4e86\u4e00\u4e2aQUIC\u7684\u90a3\u4e9b\u4e8b\u7cfb\u5217\u6587\u7ae0\uff0c\u70b9\u51fb\u94fe\u63a5\uff0c\u53ef\u4ee5\u770b\u5230\u4f5c\u8005\u7684\u4e00\u4e2aTCP\/IP\u7cfb\u5217\u6587\u7ae0\uff0c\u5206\u522b\u8bb2\u4e86TCP\u548cQUIC\u7684\u4e00\u4e9b\u4e1c\u897f\uff0e TCP 1. MSS Maximum Segment Size\uff0c&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[45,100],"class_list":["post-1184","post","type-post","status-publish","format-standard","hentry","category-10","tag-quic","tag-tcp"],"_links":{"self":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1184","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1184"}],"version-history":[{"count":1,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1184\/revisions"}],"predecessor-version":[{"id":1191,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/1184\/revisions\/1191"}],"wp:attachment":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1184"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1184"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1184"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}