{"id":2075,"date":"2026-04-21T14:28:16","date_gmt":"2026-04-21T06:28:16","guid":{"rendered":"http:\/\/www.preluna.xyz\/?p=2075"},"modified":"2026-04-21T14:37:28","modified_gmt":"2026-04-21T06:37:28","slug":"tcp%e6%8a%a5%e6%96%87%e6%ae%b5%e5%92%8c-udp%e7%94%a8%e6%88%b7%e6%95%b0%e6%8d%ae%e6%8a%a5","status":"publish","type":"post","link":"http:\/\/www.preluna.xyz\/index.php\/2026\/04\/21\/tcp%e6%8a%a5%e6%96%87%e6%ae%b5%e5%92%8c-udp%e7%94%a8%e6%88%b7%e6%95%b0%e6%8d%ae%e6%8a%a5\/preluna\/text\/","title":{"rendered":"TCP\u201c\u62a5\u6587\u6bb5\u201d\u548c UDP\u201c\u7528\u6237\u6570\u636e\u62a5\u201d"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">\u4e00\u3001\u5148\u628a\u6700\u5bb9\u6613\u6df7\u7684\u5730\u65b9\u634b\u987a\uff1aTCP\u201c\u62a5\u6587\u6bb5\u201d\u548c UDP\u201c\u7528\u6237\u6570\u636e\u62a5\u201d\u5230\u5e95\u6709\u4ec0\u4e48\u533a\u522b<\/h2>\n\n\n\n<p>\u8fd9\u90e8\u5206\u5728\u8003\u7814\u91cc\u5f88\u5bb9\u6613\u88ab\u4e00\u53e5\u201cTCP \u9762\u5411\u8fde\u63a5\u3001UDP \u65e0\u8fde\u63a5\u201d\u5e26\u8fc7\u53bb\uff0c\u4f46\u771f\u6b63\u505a\u9898\u65f6\uff0c\u5f80\u5f80\u8003\u7684\u662f\u66f4\u7ec6\u7684\u62a5\u6587\u3001\u5b57\u6bb5\u3001\u8fb9\u754c\u548c\u673a\u5236\u5dee\u5f02\u3002<\/p>\n\n\n\n<p>\u5148\u8bf4\u4e00\u4e2a\u5f88\u5173\u952e\u7684\u8868\u8ff0\uff1a\u4f20\u8f93\u5c42\u91cc\uff0cUDP \u7684 PDU \u901a\u5e38\u53eb\u201cUDP \u7528\u6237\u6570\u636e\u62a5\u201d\uff0cTCP \u7684 PDU \u901a\u5e38\u53eb\u201cTCP \u62a5\u6587\u6bb5\u201d\u3002\u518d\u5f80\u4e0b\u5c01\u88c5\u5230\u7f51\u7edc\u5c42\uff0c\u7edf\u4e00\u90fd\u4f1a\u53d8\u6210 IP \u6570\u636e\u62a5\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u4e25\u683c\u6765\u8bf4\uff0c\u5e38\u8bf4\u7684\u201cTCP \u6570\u636e\u5305\u201d\u548c\u201cUDP \u6570\u636e\u5305\u201d\u53ea\u662f\u53e3\u8bed\u5316\u8bf4\u6cd5\uff0c\u8003\u8bd5\u91cc\u66f4\u89c4\u8303\u7684\u53eb\u6cd5\u8fd8\u662f\u201cTCP \u62a5\u6587\u6bb5\u201d\u201cUDP \u7528\u6237\u6570\u636e\u62a5\u201d\u3002<\/p>\n\n\n\n<p>\u4e8c\u8005\u6700\u6838\u5fc3\u7684\u5dee\u522b\uff0c\u4e0d\u53ea\u662f\u201c\u662f\u5426\u53ef\u9760\u201d\uff0c\u800c\u662f\u201c\u4f20\u8f93\u5bf9\u8c61\u7684\u7ec4\u7ec7\u65b9\u5f0f\u201d\u4e0d\u540c\u3002<\/p>\n\n\n\n<p>UDP \u9762\u5411\u62a5\u6587\u3002\u5e94\u7528\u5c42\u4ea4\u7ed9 UDP \u4e00\u6761\u62a5\u6587\uff0cUDP \u901a\u5e38\u5c31\u6309\u8fd9\u4e00\u6761\u62a5\u6587\u6765\u53d1\u9001\uff0c\u63a5\u6536\u65b9\u4e00\u6b21\u4e5f\u6309\u4e00\u4e2a\u5b8c\u6574\u62a5\u6587\u6765\u4ea4\u4ed8\u3002\u4e5f\u5c31\u662f\u8bf4\uff0cUDP \u4fdd\u7559\u5e94\u7528\u5c42\u62a5\u6587\u8fb9\u754c\u3002\u53d1 3 \u6b21\uff0c\u5c31\u5bf9\u5e94 3 \u4e2a\u72ec\u7acb\u7684 UDP \u7528\u6237\u6570\u636e\u62a5\uff1b\u63a5\u6536\u65b9\u4e0d\u4f1a\u628a\u4e24\u6b21\u53d1\u9001\u81ea\u52a8\u62fc\u8d77\u6765\uff0c\u4e5f\u4e0d\u4f1a\u628a\u4e00\u6b21\u53d1\u9001\u81ea\u52a8\u62c6\u6210\u591a\u6b21\u4ea4\u4ed8\u7ed9\u5e94\u7528\u5c42\u3002<\/p>\n\n\n\n<p>TCP \u9762\u5411\u5b57\u8282\u6d41\u3002\u5e94\u7528\u5c42\u770b\u5230\u7684\u662f\u8fde\u7eed\u5b57\u8282\u5e8f\u5217\uff0c\u800c\u4e0d\u662f\u4e00\u6761\u4e00\u6761\u72ec\u7acb\u6d88\u606f\u3002\u5e94\u7528\u5c42\u5373\u4f7f\u5206\u4e24\u6b21 write\uff0c\u4e5f\u53ef\u80fd\u88ab TCP \u5408\u5e76\u5230\u4e00\u4e2a\u62a5\u6587\u6bb5\u91cc\u53d1\u9001\uff1b\u4e5f\u53ef\u80fd\u4e00\u6b21 write \u5f88\u5927\uff0c\u88ab TCP \u62c6\u6210\u591a\u4e2a\u62a5\u6587\u6bb5\u53d1\u9001\u3002\u63a5\u6536\u65b9\u62ff\u5230\u7684\u4e5f\u662f\u8fde\u7eed\u5b57\u8282\u6d41\uff0c\u56e0\u6b64 TCP \u4e0d\u4fdd\u7559\u5e94\u7528\u5c42\u6d88\u606f\u8fb9\u754c\u3002\u8fd9\u662f TCP \u548c UDP \u5728\u201c\u62a5\u6587\u201d\u5c42\u9762\u6700\u5927\u7684\u672c\u8d28\u533a\u522b\uff0c\u4e5f\u662f\u8003\u8bd5\u91cc\u7279\u522b\u7231\u6df7\u6dc6\u7684\u4e00\u70b9\u3002<\/p>\n\n\n\n<p>\u4ece\u9996\u90e8\u770b\uff0cUDP \u9996\u90e8\u5f88\u77ed\uff0c\u53ea\u6709 8B\uff0c\u5b57\u6bb5\u4e5f\u5c11\uff1a\u6e90\u7aef\u53e3\u3001\u76ee\u7684\u7aef\u53e3\u3001\u957f\u5ea6\u3001\u68c0\u9a8c\u548c\u3002\u5b83\u6709\u957f\u5ea6\u5b57\u6bb5\uff0c\u6240\u4ee5 UDP \u7528\u6237\u6570\u636e\u62a5\u7684\u603b\u957f\u5ea6\u53ef\u4ee5\u76f4\u63a5\u5728 UDP \u9996\u90e8\u91cc\u770b\u5230\u3002<\/p>\n\n\n\n<p>TCP \u9996\u90e8\u6700\u5c0f 20B\uff0c\u53ef\u53d8\u957f\uff0c\u56e0\u4e3a\u53ef\u4ee5\u5e26\u9009\u9879\u3002\u5b83\u7684\u5b57\u6bb5\u660e\u663e\u66f4\u591a\uff1a\u6e90\u7aef\u53e3\u3001\u76ee\u7684\u7aef\u53e3\u3001\u5e8f\u53f7\u3001\u786e\u8ba4\u53f7\u3001\u6570\u636e\u504f\u79fb\u3001\u6807\u5fd7\u4f4d\u3001\u7a97\u53e3\u3001\u6821\u9a8c\u548c\u3001\u7d27\u6025\u6307\u9488\uff0c\u4ee5\u53ca\u82e5\u5e72\u9009\u9879\u3002\u4e5f\u6b63\u56e0\u4e3a TCP \u8981\u5b9e\u73b0\u53ef\u9760\u4f20\u8f93\u3001\u6d41\u91cf\u63a7\u5236\u3001\u62e5\u585e\u63a7\u5236\uff0c\u6240\u4ee5\u5b83\u7684\u9996\u90e8\u8fdc\u6bd4 UDP \u590d\u6742\u3002<\/p>\n\n\n\n<p>\u53ef\u4ee5\u628a\u4e8c\u8005\u5148\u8bb0\u6210\u8fd9\u6837\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u5bf9\u6bd4\u9879<\/th><th>UDP<\/th><th>TCP<\/th><\/tr><\/thead><tbody><tr><td>\u8fde\u63a5\u65b9\u5f0f<\/td><td>\u65e0\u8fde\u63a5<\/td><td>\u9762\u5411\u8fde\u63a5<\/td><\/tr><tr><td>\u53ef\u9760\u6027<\/td><td>\u4e0d\u4fdd\u8bc1\u53ef\u9760<\/td><td>\u53ef\u9760\u4f20\u8f93<\/td><\/tr><tr><td>\u4f20\u8f93\u5bf9\u8c61<\/td><td>\u9762\u5411\u62a5\u6587<\/td><td>\u9762\u5411\u5b57\u8282\u6d41<\/td><\/tr><tr><td>\u662f\u5426\u4fdd\u7559\u6d88\u606f\u8fb9\u754c<\/td><td>\u4fdd\u7559<\/td><td>\u4e0d\u4fdd\u7559<\/td><\/tr><tr><td>\u9996\u90e8\u957f\u5ea6<\/td><td>8B<\/td><td>\u6700\u5c0f 20B\uff0c\u53ef\u53d8<\/td><\/tr><tr><td>\u662f\u5426\u6709\u5e8f<\/td><td>\u4e0d\u4fdd\u8bc1<\/td><td>\u4fdd\u8bc1\u6309\u5e8f\u4ea4\u4ed8<\/td><\/tr><tr><td>\u6d41\u91cf\u63a7\u5236<\/td><td>\u65e0<\/td><td>\u6709<\/td><\/tr><tr><td>\u62e5\u585e\u63a7\u5236<\/td><td>\u65e0<\/td><td>\u6709<\/td><\/tr><tr><td>\u5178\u578b\u5355\u4f4d<\/td><td>UDP \u7528\u6237\u6570\u636e\u62a5<\/td><td>TCP \u62a5\u6587\u6bb5<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u8003\u8bd5\u91cc\u8fd8\u6709\u4e00\u4e2a\u5e38\u89c1\u9677\u9631\uff1aUDP \u7684\u201c\u957f\u5ea6\u201d\u662f UDP \u9996\u90e8\u5b57\u6bb5\u4e4b\u4e00\uff1bTCP \u9996\u90e8\u91cc\u6ca1\u6709\u4e13\u95e8\u7684\u201c\u603b\u957f\u5ea6\u5b57\u6bb5\u201d\uff0cTCP \u62a5\u6587\u6bb5\u957f\u5ea6\u8981\u7ed3\u5408 IP \u5c42\u957f\u5ea6\u6765\u63a8\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u3001TCP \u62a5\u6587\u6bb5\u9996\u90e8\u4e2d\u6700\u5e38\u8003\u7684\u6807\u5fd7\u5b57\u6bb5\u6709\u54ea\u4e9b<\/h2>\n\n\n\n<p>\u8003\u7814\u91cc\u6700\u5e38\u8003\u7684\u662f 6 \u4e2a\u7ecf\u5178\u6807\u5fd7\u4f4d\uff0c\u4e5f\u5c31\u662f\uff1a<\/p>\n\n\n\n<p><code>URG\u3001ACK\u3001PSH\u3001RST\u3001SYN\u3001FIN<\/code><\/p>\n\n\n\n<p>\u73b0\u5728\u5f88\u591a\u8d44\u6599\u8fd8\u4f1a\u770b\u5230 <code>ECE\u3001CWR<\/code>\uff0c\u90a3\u662f\u4e0e ECN \u76f8\u5173\u7684\u6269\u5c55\u6807\u5fd7\u4f4d\u3002\u82e5\u662f 408 \u98ce\u683c\u6216\u5e38\u89c4\u8003\u7814\u9898\uff0c\u9ed8\u8ba4\u5148\u628a\u524d\u9762 6 \u4e2a\u5403\u900f\uff0c\u5df2\u7ecf\u8db3\u591f\u5e94\u5bf9\u7edd\u5927\u591a\u6570\u9898\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. SYN\uff1a\u5efa\u7acb\u8fde\u63a5<\/h3>\n\n\n\n<p>SYN = Synchronize Sequence Numbers\uff0c\u7528\u4e8e\u5efa\u7acb\u8fde\u63a5\u65f6\u540c\u6b65\u5e8f\u53f7\u3002<\/p>\n\n\n\n<p>\u5b83\u6700\u5178\u578b\u5730\u51fa\u73b0\u5728\u4e09\u6b21\u63e1\u624b\u91cc\u3002\u53ea\u8981\u770b\u5230 SYN\uff0c\u57fa\u672c\u5c31\u8981\u8054\u60f3\u5230\u201c\u8fde\u63a5\u5efa\u7acb\u201d\u3002\u5e76\u4e14\u8981\u8bb0\u4f4f\u4e00\u4e2a\u6781\u5176\u91cd\u8981\u7684\u89c4\u5219\uff1a<\/p>\n\n\n\n<p><strong>SYN \u4f1a\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u53e5\u8bdd\u540e\u9762\u505a\u4e09\u6b21\u63e1\u624b\u9898\u65f6\u975e\u5e38\u5173\u952e\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. ACK\uff1a\u786e\u8ba4\u6709\u6548<\/h3>\n\n\n\n<p>ACK \u4f4d\u7f6e 1\uff0c\u8868\u793a\u201c\u786e\u8ba4\u53f7\u5b57\u6bb5\u6709\u6548\u201d\u3002<\/p>\n\n\n\n<p>\u6ce8\u610f\u4e0d\u662f\u8bf4\u201c\u6709 ACK \u6807\u5fd7\u5c31\u4e00\u5b9a\u53ea\u662f\u5728\u786e\u8ba4\u201d\uff0c\u800c\u662f\u8bf4\u201c\u786e\u8ba4\u53f7\u8fd9\u4e2a\u5b57\u6bb5\u6b64\u65f6\u53ef\u4ee5\u7528\u201d\u3002\u5efa\u7acb\u8fde\u63a5\u4ee5\u540e\uff0c\u51e0\u4e4e\u6240\u6709 TCP \u62a5\u6587\u6bb5\u90fd\u4f1a\u5e26 ACK=1\u3002<\/p>\n\n\n\n<p>\u8003\u8bd5\u91cc\u5e38\u89c1\u8bef\u533a\u662f\u628a ACK \u7406\u89e3\u6210\u201c\u786e\u8ba4\u62a5\u6587\u6bb5\u201d\u3002\u5b9e\u9645\u4e0a\uff0c\u4e00\u4e2a\u62a5\u6587\u6bb5\u53ef\u4ee5\u540c\u65f6\u5e26\u591a\u4e2a\u6807\u5fd7\uff0c\u6bd4\u5982 <code>SYN + ACK<\/code>\uff0c\u8fd9\u5728\u4e09\u6b21\u63e1\u624b\u7b2c\u4e8c\u6b65\u91cc\u5c31\u4f1a\u51fa\u73b0\u3002<\/p>\n\n\n\n<p>\u7eaf ACK \u672c\u8eab<strong>\u4e0d\u6d88\u8017\u5e8f\u53f7<\/strong>\u3002\u8fd9\u4e5f\u662f\u505a\u9898\u7684\u6838\u5fc3\u89c4\u5219\u4e4b\u4e00\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. FIN\uff1a\u91ca\u653e\u8fde\u63a5<\/h3>\n\n\n\n<p>FIN = Finish\uff0c\u8868\u793a\u53d1\u9001\u65b9\u5df2\u7ecf\u6ca1\u6709\u6570\u636e\u8981\u53d1\u4e86\uff0c\u5e0c\u671b\u91ca\u653e\u8fde\u63a5\u3002<\/p>\n\n\n\n<p>\u5b83\u4e3b\u8981\u7528\u4e8e\u56db\u6b21\u6325\u624b\u3002\u548c SYN \u4e00\u6837\uff1a<\/p>\n\n\n\n<p><strong>FIN \u4e5f\u4f1a\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u662f\u6325\u624b\u9898\u6700\u5bb9\u6613\u9519\u7684\u5730\u65b9\u4e4b\u4e00\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. RST\uff1a\u590d\u4f4d\u8fde\u63a5<\/h3>\n\n\n\n<p>RST = Reset\uff0c\u7528\u4e8e\u5f02\u5e38\u60c5\u51b5\uff0c\u8868\u793a\u8fde\u63a5\u51fa\u9519\uff0c\u6216\u8005\u4e00\u65b9\u60f3\u5f3a\u5236\u4e2d\u6b62\u8fde\u63a5\u3002<\/p>\n\n\n\n<p>\u6bd4\u5982\u8bbf\u95ee\u4e00\u4e2a\u4e0d\u5b58\u5728\u7684\u7aef\u53e3\uff0c\u6216\u8005\u8fde\u63a5\u72b6\u6001\u5f02\u5e38\uff0c\u53ef\u80fd\u6536\u5230 RST\u3002\u8003\u9898\u91cc\u5e38\u628a\u5b83\u548c FIN \u5bf9\u6bd4\uff1aFIN \u662f\u6b63\u5e38\u7ed3\u675f\uff0cRST \u662f\u5f02\u5e38\u590d\u4f4d\u6216\u5f3a\u5236\u4e2d\u65ad\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. PSH\uff1a\u5c3d\u5feb\u4ea4\u4ed8<\/h3>\n\n\n\n<p>PSH = Push\uff0c\u8868\u793a\u63a5\u6536\u65b9\u5e94\u5c3d\u5feb\u628a\u6570\u636e\u4ea4\u7ed9\u5e94\u7528\u8fdb\u7a0b\uff0c\u800c\u4e0d\u8981\u7ee7\u7eed\u5728\u7f13\u51b2\u533a\u91cc\u7b49\u5f85\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u6807\u5fd7\u4f4d\u5728\u8003\u7814\u4e2d\u4e00\u822c\u4e0d\u4f1a\u6df1\u6316\u5b9e\u73b0\u7ec6\u8282\uff0c\u66f4\u91cd\u8981\u7684\u662f\u77e5\u9053\u5b83\u7684\u542b\u4e49\uff1a<strong>\u63d0\u793a\u5c3d\u5feb\u4e0a\u4ea4\u5e94\u7528\u5c42\u3002<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6. URG\uff1a\u7d27\u6025\u6570\u636e<\/h3>\n\n\n\n<p>URG = Urgent\uff0c\u8868\u793a\u7d27\u6025\u6307\u9488\u5b57\u6bb5\u6709\u6548\uff0c\u62a5\u6587\u6bb5\u4e2d\u6709\u7d27\u6025\u6570\u636e\uff0c\u5e94\u4f18\u5148\u5904\u7406\u3002<\/p>\n\n\n\n<p>\u8fd9\u90e8\u5206\u73b0\u5728\u5de5\u7a0b\u5b9e\u8df5\u91cc\u4e0d\u7b97\u5e38\u89c1\uff0c\u4f46\u8003\u9898\u91cc\u4f1a\u628a\u5b83\u4f5c\u4e3a\u9996\u90e8\u5b57\u6bb5\u8bc6\u522b\u9898\u6765\u8003\u3002\u8bb0\u6cd5\u5f88\u7b80\u5355\uff1aURG \u4e00\u51fa\u73b0\uff0c\u5c31\u8981\u60f3\u5230\u201c\u7d27\u6025\u6307\u9488\u6709\u6548\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e09\u3001TCP \u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\uff0c\u5230\u5e95\u8868\u793a\u4ec0\u4e48<\/h2>\n\n\n\n<p>\u8fd9\u4e2a\u5b57\u6bb5\u662f\u5f88\u591a\u4eba\u770b\u4e86\u5f88\u591a\u904d\u8fd8\u662f\u4e0d\u624e\u5b9e\u7684\u5730\u65b9\uff0c\u56e0\u4e3a\u201c\u7a97\u53e3\u201d\u8fd9\u4e2a\u8bcd\u5728\u6570\u636e\u94fe\u8def\u5c42\u3001\u4f20\u8f93\u5c42\u91cc\u90fd\u51fa\u73b0\u8fc7\uff0c\u5bb9\u6613\u6df7\u3002<\/p>\n\n\n\n<p>TCP \u9996\u90e8\u91cc\u7684\u201c\u7a97\u53e3\u201d\u5b57\u6bb5\uff0c\u901a\u5e38\u6307\u7684\u662f<strong>\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3<\/strong>\uff0c\u4e5f\u5c31\u662f\u82f1\u6587\u5e38\u8bf4\u7684 <code>rwnd<\/code>\u3002<\/p>\n\n\n\n<p>\u5b83\u7684\u542b\u4e49\u662f\uff1a<\/p>\n\n\n\n<p><strong>\u63a5\u6536\u65b9\u544a\u8bc9\u53d1\u9001\u65b9\uff1a\u6211\u5f53\u524d\u63a5\u6536\u7f13\u5b58\u91cc\u8fd8\u80fd\u63a5\u6536\u591a\u5c11\u5b57\u8282\u3002<\/strong><\/p>\n\n\n\n<p>\u6ce8\u610f\u4e24\u4e2a\u5173\u952e\u8bcd\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u662f\u201c\u63a5\u6536\u65b9\u901a\u544a\u201d\u7684\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u8fd9\u4e2a\u5b57\u6bb5\u4e0d\u662f\u53d1\u9001\u65b9\u968f\u4fbf\u586b\u7684\uff0c\u800c\u662f\u63a5\u6536\u65b9\u6839\u636e\u81ea\u5df1\u63a5\u6536\u7f13\u5b58\u7684\u5269\u4f59\u7a7a\u95f4\uff0c\u544a\u8bc9\u5bf9\u65b9\u4e00\u4e2a\u6570\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\uff0c\u5355\u4f4d\u662f\u201c\u5b57\u8282\u201d\uff0c\u4e0d\u662f\u201c\u62a5\u6587\u6bb5\u4e2a\u6570\u201d\u3002\u8fd9\u548c\u5f88\u591a\u94fe\u8def\u5c42\u534f\u8bae\u6309\u5e27\u7f16\u53f7\u3001\u6309\u5e27\u8ba1\u6570\u5f88\u4e0d\u4e00\u6837\u3002TCP \u662f\u6309\u5b57\u8282\u7f16\u53f7\u7684\uff0c\u6240\u4ee5\u7a97\u53e3\u672c\u8d28\u4e0a\u4e5f\u662f\u6309\u5b57\u8282\u5ea6\u91cf\u7684\u3002<\/p>\n\n\n\n<p>\u53ef\u4ee5\u628a\u5b83\u7406\u89e3\u6210\u4e00\u53e5\u975e\u5e38\u76f4\u767d\u7684\u8bdd\uff1a<\/p>\n\n\n\n<p>\u201c\u4f60\u6700\u591a\u8fd8\u53ef\u4ee5\u7ee7\u7eed\u7ed9\u6211\u53d1\u8fd9\u4e48\u591a\u5b57\u8282\uff0c\u518d\u591a\u6211\u8fd9\u8fb9\u7f13\u5b58\u53ef\u80fd\u5c31\u88c5\u4e0d\u4e0b\u4e86\u3002\u201d<\/p>\n\n\n\n<p>\u6240\u4ee5 TCP \u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\u4f53\u73b0\u7684\u662f<strong>\u6d41\u91cf\u63a7\u5236<\/strong>\u601d\u60f3\u3002\u5b83\u89e3\u51b3\u7684\u4e0d\u662f\u201c\u7f51\u7edc\u5835\u4e0d\u5835\u201d\u7684\u95ee\u9898\uff0c\u800c\u662f\u201c\u63a5\u6536\u65b9\u6765\u4e0d\u6765\u5f97\u53ca\u6536\u201d\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u56db\u3001\u53d1\u9001\u65b9\u7684\u7a97\u53e3\u5927\u5c0f\u5230\u5e95\u53d6\u51b3\u4e8e\u4ec0\u4e48<\/h2>\n\n\n\n<p>\u8fd9\u662f\u4e00\u4e2a\u975e\u5e38\u9ad8\u9891\u8003\u70b9\u3002<\/p>\n\n\n\n<p>TCP \u53d1\u9001\u65b9\u771f\u6b63\u80fd\u53d1\u9001\u7684\u6570\u636e\u91cf\uff0c\u4e0d\u662f\u53ea\u770b\u63a5\u6536\u65b9\u7a97\u53e3\uff0c\u4e5f\u4e0d\u662f\u53ea\u770b\u7f51\u7edc\u62e5\u585e\u60c5\u51b5\uff0c\u800c\u662f\u540c\u65f6\u53d7\u4e24\u65b9\u9762\u7ea6\u675f\uff1a<\/p>\n\n\n\n<p><code>\u53d1\u9001\u7a97\u53e3 = min(rwnd, cwnd)<\/code><\/p>\n\n\n\n<p>\u8fd9\u91cc\uff1a<\/p>\n\n\n\n<p><code>rwnd<\/code> \u662f\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3\uff0c\u53cd\u6620\u63a5\u6536\u65b9\u5904\u7406\u80fd\u529b\uff0c\u5c5e\u4e8e\u6d41\u91cf\u63a7\u5236\u3002<br><code>cwnd<\/code> \u662f\u62e5\u585e\u7a97\u53e3\uff0c\u53cd\u6620\u7f51\u7edc\u62e5\u585e\u60c5\u51b5\uff0c\u5c5e\u4e8e\u62e5\u585e\u63a7\u5236\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u771f\u6b63\u7684\u7ed3\u8bba\u662f\uff1a<\/p>\n\n\n\n<p><strong>\u53d1\u9001\u65b9\u7a97\u53e3\u5927\u5c0f\u53d6\u51b3\u4e8e\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3\u548c\u62e5\u585e\u7a97\u53e3\u4e8c\u8005\u4e2d\u8f83\u5c0f\u8005\u3002<\/strong><\/p>\n\n\n\n<p>\u5982\u679c\u9898\u76ee\u53ea\u8003\u6d41\u91cf\u63a7\u5236\uff0c\u5f80\u5f80\u8bf4\u201c\u53d1\u9001\u7a97\u53e3\u7531\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3\u51b3\u5b9a\u201d\uff1b<br>\u5982\u679c\u9898\u76ee\u628a\u62e5\u585e\u63a7\u5236\u4e5f\u5e26\u8fdb\u6765\uff0c\u5c31\u8981\u5199\u66f4\u5b8c\u6574\u7684\u7248\u672c\uff1a<code>min(rwnd, cwnd)<\/code>\u3002<\/p>\n\n\n\n<p>\u8fdb\u4e00\u6b65\u8bf4\uff0c\u53d1\u9001\u65b9\u201c\u6b64\u523b\u8fd8\u80fd\u7ee7\u7eed\u53d1\u9001\u591a\u5c11\u201d\uff0c\u8fd8\u8981\u51cf\u53bb\u90a3\u4e9b\u201c\u5df2\u7ecf\u53d1\u51fa\u4f46\u8fd8\u6ca1\u88ab\u786e\u8ba4\u7684\u6570\u636e\u201d\u3002\u6240\u4ee5\u66f4\u7ec6\u4e00\u70b9\u5730\u7406\u89e3\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>min(rwnd, cwnd)<\/code> \u51b3\u5b9a\u53d1\u9001\u7a97\u53e3\u4e0a\u9650<\/li>\n\n\n\n<li>\u5df2\u53d1\u9001\u672a\u786e\u8ba4\u7684\u6570\u636e\u5360\u7528\u4e86\u4e00\u90e8\u5206\u7a97\u53e3<\/li>\n\n\n\n<li>\u5269\u4e0b\u90a3\u90e8\u5206\uff0c\u624d\u662f\u5f53\u524d\u8fd8\u80fd\u518d\u53d1\u7684\u6570\u636e\u91cf<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u4e2a\u5728\u8ba1\u7b97\u9898\u91cc\u4f1a\u4f53\u73b0\u4e3a\u201c\u53ef\u53d1\u9001\u7a97\u53e3\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e94\u3001MSS \u5230\u5e95\u662f\u4ec0\u4e48\uff0c\u548c MTU \u6709\u4ec0\u4e48\u5173\u7cfb<\/h2>\n\n\n\n<p>MSS = Maximum Segment Size\uff0c\u6700\u5927\u62a5\u6587\u6bb5\u957f\u5ea6\u3002<\/p>\n\n\n\n<p>\u66f4\u51c6\u786e\u5730\u8bf4\uff0cMSS \u6307\u7684\u662f\uff1a<\/p>\n\n\n\n<p><strong>\u4e00\u4e2a TCP \u62a5\u6587\u6bb5\u4e2d\uff0c\u6570\u636e\u90e8\u5206\u7684\u6700\u5927\u957f\u5ea6\u3002<\/strong><\/p>\n\n\n\n<p>\u6ce8\u610f\uff0c\u662f<strong>TCP \u6570\u636e\u90e8\u5206<\/strong>\uff0c\u4e0d\u5305\u62ec TCP \u9996\u90e8\uff0c\u4e5f\u4e0d\u5305\u62ec IP \u9996\u90e8\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u6982\u5ff5\u5e38\u548c MTU \u4e00\u8d77\u51fa\u73b0\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>MTU\uff1a\u94fe\u8def\u5c42\u6700\u5927\u4f20\u8f93\u5355\u5143\uff0c\u6307\u4e00\u4e2a\u94fe\u8def\u5c42\u5e27\u4e2d\u80fd\u627f\u8f7d\u7684\u7f51\u7edc\u5c42\u6570\u636e\u7684\u6700\u5927\u957f\u5ea6<\/li>\n\n\n\n<li>MSS\uff1aTCP \u4e00\u6b21\u613f\u610f\u653e\u8fdb\u4e00\u4e2a\u62a5\u6587\u6bb5\u91cc\u7684\u6700\u5927 TCP \u8d1f\u8f7d\u957f\u5ea6<\/li>\n<\/ul>\n\n\n\n<p>\u5728\u4e0d\u8003\u8651 IP\/TCP \u9009\u9879\u65f6\uff0c\u5e38\u89c1\u4ee5\u592a\u7f51\u73af\u5883\u4e0b\uff1a<\/p>\n\n\n\n<p><code>MSS = MTU - IP\u9996\u90e8\u957f\u5ea6 - TCP\u9996\u90e8\u957f\u5ea6<\/code><\/p>\n\n\n\n<p>\u82e5\u4ee5\u592a\u7f51 MTU = 1500B\uff0cIPv4 \u9996\u90e8 20B\uff0cTCP \u9996\u90e8 20B\uff0c\u5219\uff1a<\/p>\n\n\n\n<p><code>MSS = 1500 - 20 - 20 = 1460B<\/code><\/p>\n\n\n\n<p>\u8fd9\u4e5f\u662f\u4e00\u9053\u975e\u5e38\u5e38\u89c1\u7684\u8ba1\u7b97\u3002<\/p>\n\n\n\n<p>MSS \u4e00\u822c\u5728<strong>\u4e09\u6b21\u63e1\u624b\u65f6\u901a\u8fc7 TCP \u9009\u9879\u534f\u5546<\/strong>\u3002\u5b83\u7684\u4f5c\u7528\u662f\u5c3d\u91cf\u8ba9 TCP \u62a5\u6587\u6bb5\u5927\u5c0f\u5408\u9002\uff0c\u907f\u514d IP \u5c42\u5206\u7247\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u516d\u3001\u4e09\u6b21\u63e1\u624b\u600e\u4e48\u8bb0\uff0c\u4e3a\u4ec0\u4e48\u662f\u4e09\u6b21\uff0c\u4e0d\u662f\u4e24\u6b21<\/h2>\n\n\n\n<p>\u4e09\u6b21\u63e1\u624b\u672c\u8d28\u4e0a\u5e72\u4e09\u4ef6\u4e8b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5ba2\u6237\u7aef\u544a\u8bc9\u670d\u52a1\u5668\uff1a\u6211\u80fd\u53d1\uff0c\u4f60\u5728\u5417<\/li>\n\n\n\n<li>\u670d\u52a1\u5668\u544a\u8bc9\u5ba2\u6237\u7aef\uff1a\u6211\u80fd\u6536\u4e5f\u80fd\u53d1\uff0c\u6211\u4e5f\u5728<\/li>\n\n\n\n<li>\u5ba2\u6237\u7aef\u518d\u544a\u8bc9\u670d\u52a1\u5668\uff1a\u6211\u77e5\u9053\u4f60\u4e5f\u80fd\u6536\u53d1\u4e86<\/li>\n<\/ol>\n\n\n\n<p>\u6240\u4ee5\u5b83\u4e0d\u53ea\u662f\u201c\u6253\u62db\u547c\u201d\uff0c\u800c\u662f\u53cc\u65b9\u90fd\u8981\u786e\u8ba4\u5f7c\u6b64\u7684\u53d1\u9001\u548c\u63a5\u6536\u80fd\u529b\u6b63\u5e38\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e09\u6b21\u63e1\u624b\u6807\u51c6\u8fc7\u7a0b<\/h3>\n\n\n\n<p>\u8bbe\u5ba2\u6237\u7aef\u521d\u59cb\u5e8f\u53f7\u4e3a <code>x<\/code>\uff0c\u670d\u52a1\u5668\u521d\u59cb\u5e8f\u53f7\u4e3a <code>y<\/code>\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u6b21\uff1a<br>\u5ba2\u6237\u7aef \u2192 \u670d\u52a1\u5668<br><code>SYN=1, seq=x<\/code><\/p>\n\n\n\n<p>\u542b\u4e49\uff1a\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\u3002<br>\u6ce8\u610f\uff1aSYN \u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\uff0c\u6240\u4ee5\u5ba2\u6237\u7aef\u4e0b\u6b21\u53d1\u9001\u7684\u5e8f\u53f7\u5e94\u4ece <code>x+1<\/code> \u5f00\u59cb\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u6b21\uff1a<br>\u670d\u52a1\u5668 \u2192 \u5ba2\u6237\u7aef<br><code>SYN=1, ACK=1, seq=y, ack=x+1<\/code><\/p>\n\n\n\n<p>\u542b\u4e49\uff1a\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u540c\u65f6\u786e\u8ba4\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u7684 SYN\u3002<br>\u8fd9\u91cc\u670d\u52a1\u5668\u81ea\u5df1\u7684 SYN \u4e5f\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\uff0c\u6240\u4ee5\u670d\u52a1\u5668\u540e\u7eed\u5e8f\u53f7\u4ece <code>y+1<\/code> \u5f00\u59cb\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u6b21\uff1a<br>\u5ba2\u6237\u7aef \u2192 \u670d\u52a1\u5668<br><code>ACK=1, seq=x+1, ack=y+1<\/code><\/p>\n\n\n\n<p>\u542b\u4e49\uff1a\u786e\u8ba4\u6536\u5230\u4e86\u670d\u52a1\u5668\u7684 SYN\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u8bb0\u5fc6\u7684\u6838\u5fc3\u89c4\u5219\u53ea\u6709\u4e09\u53e5<\/h3>\n\n\n\n<p>\u7b2c\u4e00\u53e5\uff1a<\/p>\n\n\n\n<p><strong>\u8c01\u53d1 SYN\uff0c\u8c01\u7684\u5e8f\u53f7\u5c31\u52a0 1\u3002<\/strong><\/p>\n\n\n\n<p>\u7b2c\u4e8c\u53e5\uff1a<\/p>\n\n\n\n<p><strong>\u786e\u8ba4\u53f7 = \u5bf9\u65b9\u5e8f\u53f7 + 1\uff08\u82e5\u5bf9\u65b9\u53d1\u7684\u662f SYN\/FIN\uff09\u6216 \u5bf9\u65b9\u5e8f\u53f7 + \u6570\u636e\u5b57\u8282\u6570\u3002<\/strong><\/p>\n\n\n\n<p>\u7b2c\u4e09\u53e5\uff1a<\/p>\n\n\n\n<p><strong>\u7eaf ACK \u4e0d\u6d88\u8017\u5e8f\u53f7\u3002<\/strong><\/p>\n\n\n\n<p>\u4f60\u4f1a\u53d1\u73b0\uff0c\u4e09\u6b21\u63e1\u624b\u4e4b\u6240\u4ee5\u770b\u8d77\u6765\u590d\u6742\uff0c\u5176\u5b9e\u53ea\u662f\u56e0\u4e3a\u540c\u65f6\u5728\u8bb0\u201c\u4e24\u6761\u65b9\u5411\u5404\u81ea\u7684\u5e8f\u53f7\u7ebf\u201d\u3002\u4e00\u65e6\u6293\u4f4f\u201c\u5404\u7b97\u5404\u7684\u201d\uff0c\u5c31\u4e0d\u4e71\u4e86\u3002<\/p>\n\n\n\n<p>\u5ba2\u6237\u7aef\u5e8f\u53f7\u7ebf\uff1a<\/p>\n\n\n\n<p><code>x \u2192 x+1<\/code><\/p>\n\n\n\n<p>\u670d\u52a1\u5668\u5e8f\u53f7\u7ebf\uff1a<\/p>\n\n\n\n<p><code>y \u2192 y+1<\/code><\/p>\n\n\n\n<p>\u5b83\u4eec\u5f7c\u6b64\u901a\u8fc7 ack \u53bb\u786e\u8ba4\u5bf9\u65b9\u5df2\u7ecf\u8d70\u5230\u4e86\u54ea\u91cc\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u4e24\u6b21\u63e1\u624b<\/h3>\n\n\n\n<p>\u8003\u7814\u5e38\u89c1\u8868\u8ff0\u662f\uff1a\u4e24\u6b21\u63e1\u624b\u65e0\u6cd5\u9632\u6b62\u5931\u6548\u7684\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\u6bb5\u7a81\u7136\u53c8\u4f20\u5230\u670d\u52a1\u5668\uff0c\u4ece\u800c\u5bfc\u81f4\u670d\u52a1\u5668\u9519\u8bef\u5efa\u7acb\u8fde\u63a5\u3002\u66f4\u901a\u4fd7\u4e00\u70b9\u8bf4\uff0c\u5c31\u662f\u670d\u52a1\u5668\u6ca1\u6cd5\u786e\u8ba4\u5ba2\u6237\u7aef\u662f\u5426\u771f\u7684\u6536\u5230\u4e86\u81ea\u5df1\u7684\u786e\u8ba4\uff0c\u4e5f\u6ca1\u6cd5\u786e\u8ba4\u53cc\u65b9\u90fd\u5df2\u8fdb\u5165\u53ef\u901a\u4fe1\u72b6\u6001\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u7b2c\u4e09\u6b21\u63e1\u624b\u7684\u672c\u8d28\uff0c\u662f\u8ba9\u670d\u52a1\u5668\u77e5\u9053\uff1a<\/p>\n\n\n\n<p>\u201c\u6211\u53d1\u7ed9\u4f60\u7684 SYN+ACK\uff0c\u4f60\u786e\u5b9e\u6536\u5230\u4e86\u3002\u201d<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e03\u3001\u56db\u6b21\u6325\u624b\u600e\u4e48\u8bb0\uff0c\u4e3a\u4ec0\u4e48\u901a\u5e38\u662f\u56db\u6b21<\/h2>\n\n\n\n<p>\u8fd9\u5757\u6bd4\u4e09\u6b21\u63e1\u624b\u66f4\u5bb9\u6613\u4e71\uff0c\u56e0\u4e3a\u5b83\u4f53\u73b0\u4e86 TCP \u7684\u5168\u53cc\u5de5\u7279\u6027\uff1a\u4e24\u4e2a\u65b9\u5411\u7684\u5173\u95ed\u662f\u5206\u5f00\u7684\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u6b21\u6325\u624b\u6807\u51c6\u8fc7\u7a0b<\/h3>\n\n\n\n<p>\u8bbe\u4e3b\u52a8\u5173\u95ed\u65b9 A\uff0c \u88ab\u52a8\u5173\u95ed\u65b9 B\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u6b21\uff1a<br>A \u2192 B<br><code>FIN=1, seq=u<\/code><\/p>\n\n\n\n<p>\u8868\u793a A \u5df2\u7ecf\u6ca1\u6709\u6570\u636e\u8981\u53d1\u4e86\u3002<br>\u6ce8\u610f\uff1aFIN \u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\uff0c\u6240\u4ee5 A \u540e\u7eed\u5e8f\u53f7\u53d8\u6210 <code>u+1<\/code>\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u6b21\uff1a<br>B \u2192 A<br><code>ACK=1, ack=u+1, seq=v<\/code><\/p>\n\n\n\n<p>\u8868\u793a B \u77e5\u9053 A \u8fd9\u8fb9\u8981\u5173\u4e86\u3002<br>\u8fd9\u4e00\u6b65\u53ea\u662f\u201c\u786e\u8ba4\u201d\uff0c\u5e76\u4e0d\u4ee3\u8868 B \u4e5f\u7acb\u5373\u5173\u95ed\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u6b21\uff1a<br>B \u2192 A<br><code>FIN=1, ACK=1, seq=w, ack=u+1<\/code><\/p>\n\n\n\n<p>\u8868\u793a B \u81ea\u5df1\u7684\u6570\u636e\u4e5f\u53d1\u9001\u5b8c\u4e86\uff0c\u73b0\u5728\u4e5f\u8bf7\u6c42\u5173\u95ed\u3002<\/p>\n\n\n\n<p>\u7b2c\u56db\u6b21\uff1a<br>A \u2192 B<br><code>ACK=1, seq=u+1, ack=w+1<\/code><\/p>\n\n\n\n<p>\u8868\u793a\u786e\u8ba4\u6536\u5230 B \u7684 FIN\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e3a\u4ec0\u4e48\u901a\u5e38\u662f\u56db\u6b21\uff0c\u4e0d\u662f\u4e09\u6b21<\/h3>\n\n\n\n<p>\u56e0\u4e3a TCP \u662f\u5168\u53cc\u5de5\u7684\u3002<\/p>\n\n\n\n<p>A \u4e0d\u53d1\u4e86\uff0c\u53ea\u4ee3\u8868 A \u2192 B \u8fd9\u4e2a\u65b9\u5411\u5173\u95ed\uff1b<br>\u4f46 B \u2192 A \u65b9\u5411\u53ef\u80fd\u8fd8\u6709\u6570\u636e\u6ca1\u53d1\u5b8c\uff0c\u6240\u4ee5 B \u5148\u53d1 ACK\uff0c\u7b49\u81ea\u5df1\u6570\u636e\u53d1\u5b8c\u540e\u518d\u53d1 FIN\u3002<\/p>\n\n\n\n<p>\u8fd9\u5c31\u662f\u201c\u56db\u6b21\u201d\u7684\u6839\u672c\u539f\u56e0\uff1a<strong>\u4e24\u4e2a\u65b9\u5411\u5206\u522b\u5173\u95ed\u3002<\/strong><\/p>\n\n\n\n<p>\u5f53\u7136\uff0c\u5728\u7279\u6b8a\u60c5\u51b5\u4e0b\uff0cB \u7b2c\u4e8c\u6b21\u548c\u7b2c\u4e09\u6b21\u53ef\u4ee5\u5408\u5e76\uff0c\u4e5f\u5c31\u662f ACK \u548c FIN \u4e00\u8d77\u53d1\u51fa\u53bb\uff0c\u4f46\u8003\u8bd5\u9ed8\u8ba4\u8bb0\u6807\u51c6\u56db\u6b21\u6325\u624b\u5c31\u591f\u4e86\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u6b21\u6325\u624b\u6700\u5b9e\u7528\u7684\u8bb0\u5fc6\u6cd5<\/h3>\n\n\n\n<p>\u53ea\u8bb0\u4e00\u53e5\u6700\u6838\u5fc3\u7684\u8bdd\uff1a<\/p>\n\n\n\n<p><strong>SYN \u548c FIN \u90fd\u8981\u5360\u4e00\u4e2a\u5e8f\u53f7\uff0c\u7eaf ACK \u4e0d\u5360\u3002<\/strong><\/p>\n\n\n\n<p>\u4e8e\u662f\u6240\u6709\u9898\u90fd\u53ef\u4ee5\u673a\u68b0\u63a8\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u770b\u5230 SYN\uff1a\u5e8f\u53f7 +1<\/li>\n\n\n\n<li>\u770b\u5230 FIN\uff1a\u5e8f\u53f7 +1<\/li>\n\n\n\n<li>\u770b\u5230\u6570\u636e\uff1a\u5e8f\u53f7 + \u6570\u636e\u5b57\u8282\u6570<\/li>\n\n\n\n<li>\u770b\u5230\u7eaf ACK\uff1a\u5e8f\u53f7\u4e0d\u53d8<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u6bd4\u6b7b\u80cc\u6bcf\u4e00\u5305\u957f\u4ec0\u4e48\u6837\u66f4\u7a33\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u516b\u3001\u600e\u4e48\u8bb0\u4e09\u6b21\u63e1\u624b\u548c\u56db\u6b21\u6325\u624b\uff0c\u4e0d\u81f3\u4e8e\u4e00\u505a\u9898\u5c31\u4e71<\/h2>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u4e4b\u6240\u4ee5\u8ba9\u4eba\u89c9\u5f97\u201c\u5305\u592a\u591a\uff0c\u592a\u590d\u6742\u201d\uff0c\u672c\u8d28\u539f\u56e0\u4e0d\u662f\u5305\u771f\u7684\u591a\uff0c\u800c\u662f\u540c\u65f6\u5728\u8ddf\u8e2a\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5ba2\u6237\u7aef\u5e8f\u53f7\u7ebf<\/li>\n\n\n\n<li>\u670d\u52a1\u5668\u5e8f\u53f7\u7ebf<\/li>\n\n\n\n<li>\u54ea\u4e9b\u6807\u5fd7\u4f4d\u6d88\u8017\u5e8f\u53f7<\/li>\n\n\n\n<li>ack \u5230\u5e95\u5728\u786e\u8ba4\u4ec0\u4e48<\/li>\n<\/ol>\n\n\n\n<p>\u771f\u6b63\u9ad8\u6548\u7684\u8bb0\u6cd5\uff0c\u4e0d\u662f\u80cc\u56fe\uff0c\u800c\u662f\u80cc\u89c4\u5219\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e00\u6761\u94c1\u5f8b\uff1aTCP \u5e8f\u53f7\u6309\u5b57\u8282\u7f16\u53f7<\/h3>\n\n\n\n<p>TCP \u7684 seq \u4e0d\u662f\u201c\u7b2c\u51e0\u4e2a\u62a5\u6587\u6bb5\u201d\uff0c\u800c\u662f<strong>\u672c\u62a5\u6587\u6bb5\u6570\u636e\u90e8\u5206\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7<\/strong>\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4e00\u65e6\u5e26\u6570\u636e\uff0c\u5e8f\u53f7\u524d\u8fdb\u91cf\u5c31\u662f\u6570\u636e\u5b57\u8282\u6570\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e8c\u6761\u94c1\u5f8b\uff1aSYN\u3001FIN \u5404\u5360\u4e00\u4e2a\u5e8f\u53f7<\/h3>\n\n\n\n<p>\u8fd9\u662f\u505a\u8fde\u63a5\u7ba1\u7406\u9898\u6700\u5173\u952e\u7684\u89c4\u5219\u3002\u63e1\u624b\u548c\u6325\u624b\u91cc\uff0c\u771f\u6b63\u8ba9\u5e8f\u53f7 +1 \u7684\uff0c\u5f80\u5f80\u5c31\u662f SYN \u548c FIN\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e09\u6761\u94c1\u5f8b\uff1a\u7eaf ACK \u4e0d\u5360\u5e8f\u53f7<\/h3>\n\n\n\n<p>\u5f88\u591a\u9898\u9519\u5c31\u9519\u5728\u628a ACK \u4e5f\u5f53\u6210\u201c\u5360\u4e00\u4e2a\u4f4d\u7f6e\u201d\u3002\u5176\u5b9e\u7eaf ACK \u53ea\u662f\u786e\u8ba4\uff0c\u4e0d\u643a\u5e26\u65b0\u6570\u636e\uff0c\u4e5f\u4e0d\u7533\u8bf7\u5efa\u7acb\/\u91ca\u653e\uff0c\u56e0\u6b64\u4e0d\u989d\u5916\u6d88\u8017\u5e8f\u53f7\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u56db\u6761\u94c1\u5f8b\uff1aack \u8868\u793a\u201c\u6211\u671f\u5f85\u6536\u5230\u4f60\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7\u201d<\/h3>\n\n\n\n<p>\u8fd9\u53e5\u8bdd\u7279\u522b\u91cd\u8981\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5 ack \u4e0d\u662f\u201c\u6211\u6536\u5230\u4e86\u54ea\u4e2a\u7f16\u53f7\u201d\uff0c\u800c\u662f\u201c\u6211\u5df2\u7ecf\u6536\u5230\u4e86\u4f60\u524d\u9762\u7684\u5185\u5bb9\uff0c\u4e0b\u4e00\u6b21\u8bf7\u4ece\u8fd9\u4e2a\u7f16\u53f7\u5f00\u59cb\u53d1\u201d\u3002<\/p>\n\n\n\n<p>\u8fd9\u6837\u4e00\u6765\uff0c<code>ack = \u5df2\u6b63\u786e\u6536\u5230\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7 + 1<\/code><\/p>\n\n\n\n<p>\u5982\u679c\u6536\u5230\u7684\u662f SYN \u6216 FIN\uff0c\u56e0\u4e3a\u5b83\u4eec\u4e5f\u5360\u4e00\u4e2a\u5e8f\u53f7\uff0c\u6240\u4ee5\u786e\u8ba4\u65f6\u4e5f\u8981\u52a0 1\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u505a\u9898\u6a21\u677f<\/h3>\n\n\n\n<p>\u4ee5\u540e\u51e1\u662f\u63e1\u624b\u6325\u624b\u9898\uff0c\u5efa\u8bae\u76f4\u63a5\u753b\u4e24\u6761\u7ebf\uff1a<\/p>\n\n\n\n<p>\u4e0a\u9762\u5199\u5ba2\u6237\u7aef\u5e8f\u53f7\u53d8\u5316\uff0c\u4e0b\u9762\u5199\u670d\u52a1\u5668\u5e8f\u53f7\u53d8\u5316\u3002<br>\u6bcf\u6765\u4e00\u4e2a\u62a5\u6587\u6bb5\uff0c\u5c31\u53ea\u505a\u4e09\u4ef6\u4e8b\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u770b\u8c01\u53d1<\/li>\n\n\n\n<li>\u770b\u5b83\u5e26\u6ca1\u5e26 SYN \/ FIN \/ \u6570\u636e<\/li>\n\n\n\n<li>\u6539\u5b83\u81ea\u5df1\u7684 seq\uff0c\u6539\u5bf9\u65b9\u7ed9\u5b83\u7684 ack<\/li>\n<\/ol>\n\n\n\n<p>\u8fd9\u4e48\u505a\u4f1a\u6bd4\u80cc\u56fe\u7a33\u5f97\u591a\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e5d\u3001\u4f8b\u9898\uff1a40Gb\/s \u7684 TCP \u591a\u4e45\u4f1a\u53d1\u751f 32 \u4f4d\u5e8f\u53f7\u7ed5\u56de<\/h2>\n\n\n\n<p>\u9898\u76ee\u672c\u8d28\u662f\u5728\u95ee\uff1a<\/p>\n\n\n\n<p>TCP \u5e8f\u53f7\u5b57\u6bb5 32 \u4f4d\uff0c\u6700\u591a\u80fd\u8868\u793a <code>2^32<\/code> \u4e2a\u4e0d\u540c\u5e8f\u53f7\u3002<br>\u5982\u679c\u4e00\u76f4\u9ad8\u901f\u53d1\u9001\u6570\u636e\uff0c\u7528\u5b8c\u8fd9\u4e00\u5708\u9700\u8981\u591a\u957f\u65f6\u95f4\uff1f<\/p>\n\n\n\n<p>\u56e0\u4e3a TCP \u5e8f\u53f7\u662f\u6309<strong>\u5b57\u8282<\/strong>\u7f16\u53f7\u7684\uff0c\u6240\u4ee5\u53ef\u7528\u5b57\u8282\u6570\u662f\u4e00\u5708\uff1a<\/p>\n\n\n\n<p><code>2^32 B<\/code><\/p>\n\n\n\n<p>\u7ebf\u8def\u901f\u7387\u662f\uff1a<\/p>\n\n\n\n<p><code>40 Gb\/s = 40 \u00d7 10^9 bit\/s<\/code><\/p>\n\n\n\n<p>\u6362\u6210\u5b57\u8282\u6bcf\u79d2\uff1a<\/p>\n\n\n\n<p><code>40 \u00d7 10^9 \u00f7 8 = 5 \u00d7 10^9 B\/s<\/code><\/p>\n\n\n\n<p>\u4e8e\u662f\u53d1\u751f\u5e8f\u53f7\u7ed5\u56de\u7684\u65f6\u95f4\u4e3a\uff1a<\/p>\n\n\n\n<p><code>2^32 \u00f7 (5 \u00d7 10^9) s<\/code><\/p>\n\n\n\n<p>\u53c8\u56e0\u4e3a\uff1a<\/p>\n\n\n\n<p><code>2^32 = 4.294967296 \u00d7 10^9<\/code><\/p>\n\n\n\n<p>\u6240\u4ee5\uff1a<\/p>\n\n\n\n<p><code>\u65f6\u95f4 \u2248 4.294967296 \u00d7 10^9 \u00f7 5 \u00d7 10^9<\/code><br><code>\u2248 0.8589934592 s<\/code><\/p>\n\n\n\n<p>\u7ea6\u7b49\u4e8e\uff1a<\/p>\n\n\n\n<p><code>0.859 s<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u672c\u9898\u7ed3\u8bba<\/h3>\n\n\n\n<p><strong>TCP \u5728 40Gb\/s \u7684\u7ebf\u8def\u4e0a\uff0c\u82e5\u5145\u5206\u5229\u7528\u5e26\u5bbd\uff0c\u5927\u7ea6 0.859 \u79d2\u5c31\u4f1a\u53d1\u751f\u4e00\u6b21 32 \u4f4d\u5e8f\u53f7\u7ed5\u56de\u3002<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u8fd9\u9898\u8003\u4ec0\u4e48<\/h3>\n\n\n\n<p>\u5b83\u8003\u7684\u662f\u4e09\u4e2a\u70b9\uff1a<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0cTCP \u5e8f\u53f7\u6309\u5b57\u8282\u7f16\u53f7\uff0c\u800c\u4e0d\u662f\u6309\u62a5\u6587\u6bb5\u7f16\u53f7\u3002<br>\u7b2c\u4e8c\uff0c32 \u4f4d\u5e8f\u53f7\u7a7a\u95f4\u662f\u4e00\u5708 <code>2^32<\/code>\u3002<br>\u7b2c\u4e09\uff0c\u901f\u7387\u5355\u4f4d\u8981\u4ece bit\/s \u6362\u6210 B\/s\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u6700\u5bb9\u6613\u9519\u7684\u5730\u65b9<\/h3>\n\n\n\n<p>\u6700\u5e38\u89c1\u9519\u8bef\u6709\u4e24\u4e2a\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u9519\u8bef\uff0c\u662f\u628a <code>2^32<\/code> \u5f53\u6210 bit \u6570\uff0c\u800c\u4e0d\u662f\u5b57\u8282\u6570\u3002<br>\u7b2c\u4e8c\u4e2a\u9519\u8bef\uff0c\u662f\u5fd8\u8bb0 <code>1B = 8bit<\/code>\uff0c\u6ca1\u6709\u628a 40Gb\/s \u6362\u7b97\u6210\u5b57\u8282\u6bcf\u79d2\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5341\u3001TCP \u7684\u7a97\u53e3\u673a\u5236\u548c\u6570\u636e\u94fe\u8def\u5c42\u6ed1\u52a8\u7a97\u53e3\u3001GBN \u4e3a\u4ec0\u4e48\u201c\u770b\u8d77\u6765\u5f88\u50cf\u201d<\/h2>\n\n\n\n<p>\u4f60\u8fd9\u4e2a\u611f\u89c9\u5b8c\u5168\u5bf9\u3002\u5b83\u4eec\u786e\u5b9e\u6709\u5171\u540c\u601d\u60f3\uff0c\u6240\u4ee5\u770b\u8d77\u6765\u5f88\u50cf\uff1b\u4f46\u53c8\u4e0d\u80fd\u76f4\u63a5\u753b\u7b49\u53f7\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u5148\u8bf4\u5b83\u4eec\u4e3a\u4ec0\u4e48\u50cf<\/h3>\n\n\n\n<p>\u5b83\u4eec\u90fd\u7528\u4e86\u201c\u6ed1\u52a8\u7a97\u53e3\u201d\u601d\u60f3\u3002<\/p>\n\n\n\n<p>\u6240\u8c13\u6ed1\u52a8\u7a97\u53e3\uff0c\u672c\u8d28\u4e0a\u5c31\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d1\u9001\u65b9\u4e0d\u5fc5\u6bcf\u53d1\u4e00\u4efd\u6570\u636e\u5c31\u505c\u4e0b\u6765\u7b49\u786e\u8ba4<\/li>\n\n\n\n<li>\u53ef\u4ee5\u8fde\u7eed\u53d1\u9001\u591a\u4e2a\u5355\u4f4d\u7684\u6570\u636e<\/li>\n\n\n\n<li>\u6536\u5230\u786e\u8ba4\u540e\uff0c\u7a97\u53e3\u5411\u524d\u6ed1\u52a8\uff0c\u7ee7\u7eed\u53d1\u9001\u540e\u9762\u7684\u6570\u636e<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u548c\u505c\u6b62-\u7b49\u5f85\u76f8\u6bd4\uff0c\u6548\u7387\u660e\u663e\u9ad8\u5f88\u591a\u3002\u6240\u4ee5\u6570\u636e\u94fe\u8def\u5c42\u7684 GBN\u3001SR\uff0c\u4ee5\u53ca\u4f20\u8f93\u5c42\u7684 TCP\uff0c\u90fd\u4f7f\u7528\u4e86\u7a97\u53e3\u601d\u60f3\u3002<\/p>\n\n\n\n<p>\u5b83\u4eec\u4e5f\u90fd\u6d89\u53ca\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5e8f\u53f7<\/li>\n\n\n\n<li>\u786e\u8ba4<\/li>\n\n\n\n<li>\u8d85\u65f6\u91cd\u4f20<\/li>\n\n\n\n<li>\u8fde\u7eed\u53d1\u9001<\/li>\n\n\n\n<li>\u6d41\u6c34\u7ebf\u4f20\u8f93<\/li>\n<\/ul>\n\n\n\n<p>\u6240\u4ee5\u521d\u5b66\u65f6\u628a TCP \u60f3\u6210\u201c\u66f4\u590d\u6742\u7684\u6ed1\u52a8\u7a97\u53e3\u534f\u8bae\u201d\u662f\u5f88\u81ea\u7136\u7684\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5341\u4e00\u3001\u4f46 TCP \u548c GBN \u4e0d\u80fd\u7b80\u5355\u7b49\u540c\uff0c\u5dee\u522b\u5f88\u5927<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u6240\u5728\u5c42\u6b21\u4e0d\u540c<\/h3>\n\n\n\n<p>GBN\u3001SR \u662f\u6570\u636e\u94fe\u8def\u5c42\u53ef\u9760\u4f20\u8f93\u673a\u5236\uff0c\u901a\u5e38\u89e3\u51b3\u7684\u662f<strong>\u4e00\u6bb5\u94fe\u8def\u4e0a\u7684\u5e27\u4f20\u8f93\u95ee\u9898<\/strong>\u3002<br>TCP \u662f\u4f20\u8f93\u5c42\u534f\u8bae\uff0c\u89e3\u51b3\u7684\u662f<strong>\u7aef\u5230\u7aef\u8fdb\u7a0b\u4e4b\u95f4\u7684\u53ef\u9760\u4f20\u8f93\u95ee\u9898<\/strong>\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e00\u70b9\u51b3\u5b9a\u4e86 TCP \u9762\u5bf9\u7684\u73af\u5883\u66f4\u590d\u6742\u3002\u5b83\u8de8\u8d8a\u591a\u4e2a\u8def\u7531\u5668\u3001\u591a\u4e2a\u94fe\u8def\uff0c\u5fc5\u987b\u8003\u8651\u7f51\u7edc\u62e5\u585e\u3001\u63a5\u6536\u7f13\u5b58\u3001\u7aef\u5230\u7aef\u65f6\u5ef6\u53d8\u5316\u7b49\u95ee\u9898\uff0c\u800c\u94fe\u8def\u5c42\u7a97\u53e3\u534f\u8bae\u5f80\u5f80\u53ea\u9488\u5bf9\u5355\u8df3\u94fe\u8def\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u7f16\u53f7\u5355\u4f4d\u4e0d\u540c<\/h3>\n\n\n\n<p>GBN \u4e00\u822c\u6309\u201c\u5e27\u201d\u7f16\u53f7\u3002<br>TCP \u6309\u201c\u5b57\u8282\u201d\u7f16\u53f7\u3002<\/p>\n\n\n\n<p>\u8fd9\u4f1a\u76f4\u63a5\u5f71\u54cd\u505a\u9898\u65b9\u5f0f\u3002TCP \u7684 seq \u548c ack \u90fd\u662f\u5b57\u8282\u7ea7\u7684\uff0c\u56e0\u6b64\u4e00\u4e2a\u62a5\u6587\u6bb5\u53d1\u9001\u4e86\u591a\u5c11\u5b57\u8282\uff0c\u5e8f\u53f7\u5c31\u63a8\u8fdb\u591a\u5c11\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. TCP \u540c\u65f6\u505a\u6d41\u91cf\u63a7\u5236\u548c\u62e5\u585e\u63a7\u5236\uff0cGBN \u4e3b\u8981\u4e0d\u662f\u5e72\u8fd9\u4e2a\u7684<\/h3>\n\n\n\n<p>GBN \u7684\u91cd\u70b9\u662f\u53ef\u9760\u4f20\u8f93\u548c\u5dee\u9519\u6062\u590d\u3002<br>TCP \u9664\u4e86\u53ef\u9760\u4f20\u8f93\uff0c\u8fd8\u8981\u505a\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6d41\u91cf\u63a7\u5236\uff1a\u522b\u628a\u63a5\u6536\u65b9\u6491\u7206<\/li>\n\n\n\n<li>\u62e5\u585e\u63a7\u5236\uff1a\u522b\u628a\u7f51\u7edc\u6253\u7206<\/li>\n<\/ul>\n\n\n\n<p>\u6240\u4ee5 TCP \u7684\u53d1\u9001\u7a97\u53e3\u4e0d\u662f\u4e00\u4e2a\u7b80\u5355\u56fa\u5b9a\u7a97\u53e3\uff0c\u800c\u662f\u540c\u65f6\u53d7 <code>rwnd<\/code> \u548c <code>cwnd<\/code> \u5f71\u54cd\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e5f\u662f TCP \u6bd4 GBN \u590d\u6742\u5f97\u591a\u7684\u6839\u672c\u539f\u56e0\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. \u786e\u8ba4\u673a\u5236\u76f8\u4f3c\uff0c\u4f46 TCP \u66f4\u7075\u6d3b<\/h3>\n\n\n\n<p>\u7ecf\u5178 GBN \u662f\u7d2f\u8ba1\u786e\u8ba4\uff0c\u4e5f\u5c31\u662f\u786e\u8ba4\u5230\u67d0\u4e00\u5e27\u4e3a\u6b62\u4e4b\u524d\u90fd\u6536\u5230\u4e86\u3002<br>TCP \u9ed8\u8ba4\u4e5f\u662f\u7d2f\u8ba1\u786e\u8ba4\uff0c\u6240\u4ee5\u8fd9\u4e5f\u662f\u4f60\u89c9\u5f97\u5b83\u50cf GBN \u7684\u4e00\u4e2a\u91cd\u8981\u539f\u56e0\u3002<\/p>\n\n\n\n<p>\u4f46 TCP \u6bd4 GBN \u7075\u6d3b\u5f97\u591a\u3002\u73b0\u4ee3 TCP \u4e2d\u53ef\u80fd\u8fd8\u6709\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5ef6\u8fdf\u786e\u8ba4<\/li>\n\n\n\n<li>\u91cd\u590d ACK<\/li>\n\n\n\n<li>\u5feb\u91cd\u4f20<\/li>\n\n\n\n<li>\u9009\u62e9\u786e\u8ba4 SACK<\/li>\n<\/ul>\n\n\n\n<p>\u6240\u4ee5 TCP \u4e0d\u662f\u6559\u6750\u91cc\u90a3\u4e2a\u201c\u7eaf\u7cb9\u7684 GBN\u201d\u3002\u5b83\u53ea\u662f\u4fdd\u7559\u4e86\u201c\u7d2f\u8ba1\u786e\u8ba4\u201d\u8fd9\u4e00\u6838\u5fc3\u5473\u9053\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. \u5931\u5e8f\u5904\u7406\u65b9\u5f0f\u4e0d\u540c<\/h3>\n\n\n\n<p>\u7ecf\u5178 GBN \u4e2d\uff0c\u63a5\u6536\u65b9\u901a\u5e38\u4e22\u5f03\u5931\u5e8f\u5230\u8fbe\u7684\u5e27\uff0c\u53ea\u786e\u8ba4\u6309\u5e8f\u5230\u8fbe\u7684\u6700\u540e\u4e00\u5e27\u3002<br>TCP \u5728\u6559\u6750\u5c42\u9762\u5e38\u5f3a\u8c03\u201c\u7d2f\u8ba1\u786e\u8ba4\u3001\u6309\u5e8f\u4ea4\u4ed8\u201d\uff0c\u6240\u4ee5\u4e5f\u6709\u7c7b\u4f3c\u5473\u9053\uff1b\u4f46\u5b9e\u9645\u5b9e\u73b0\u91cc\uff0cTCP \u5f80\u5f80\u4f1a\u7f13\u5b58\u5931\u5e8f\u62a5\u6587\u6bb5\uff0c\u5e76\u501f\u52a9 SACK \u7b49\u673a\u5236\u4f18\u5316\u91cd\u4f20\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4ece\u8003\u7814\u505a\u9898\u89d2\u5ea6\uff0c\u53ef\u4ee5\u8bb0\u6210\uff1a<\/p>\n\n\n\n<p><strong>TCP \u5728\u786e\u8ba4\u98ce\u683c\u4e0a\u66f4\u63a5\u8fd1\u7d2f\u8ba1\u786e\u8ba4\uff0c\u4f46\u6574\u4f53\u5e76\u4e0d\u7b49\u540c\u4e8e GBN\u3002<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6. \u91cd\u4f20\u7b56\u7565\u4e0d\u540c<\/h3>\n\n\n\n<p>GBN \u4e00\u65e6\u67d0\u5e27\u4e22\u5931\uff0c\u53d1\u9001\u65b9\u8d85\u65f6\u540e\u5f80\u5f80\u4ece\u8be5\u5e27\u5f00\u59cb\uff0c\u628a\u540e\u9762\u5df2\u7ecf\u53d1\u8fc7\u7684\u90fd\u91cd\u4f20\u3002<br>TCP \u4e0d\u4e00\u5b9a\u8fd9\u6837\u201c\u6574\u6bb5\u56de\u9000\u201d\uff0c\u5b83\u6709\u66f4\u590d\u6742\u7684\u91cd\u4f20\u5224\u65ad\u65b9\u5f0f\uff0c\u4f8b\u5982\u57fa\u4e8e\u8d85\u65f6\u3001\u57fa\u4e8e\u91cd\u590d ACK \u7684\u5feb\u91cd\u4f20\u7b49\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5341\u4e8c\u3001\u600e\u4e48\u5728\u8003\u8bd5\u91cc\u5feb\u901f\u533a\u5206\u201cTCP \u7a97\u53e3\u201d\u548c\u201c\u6570\u636e\u94fe\u8def\u5c42\u6ed1\u52a8\u7a97\u53e3\u201d<\/h2>\n\n\n\n<p>\u6211\u89c9\u5f97\u53ef\u4ee5\u6293\u4e0b\u9762\u8fd9\u6761\u4e3b\u7ebf\uff1a<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u5982\u679c\u9898\u76ee\u5f3a\u8c03\u201c\u7aef\u5230\u7aef\u3001\u5b57\u8282\u6d41\u3001\u63a5\u6536\u7a97\u53e3\u3001\u62e5\u585e\u7a97\u53e3\u3001\u4e09\u6b21\u63e1\u624b\u3001\u56db\u6b21\u6325\u624b\u201d<\/h3>\n\n\n\n<p>\u90a3\u57fa\u672c\u5c31\u662f TCP \u89c6\u89d2\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u5982\u679c\u9898\u76ee\u5f3a\u8c03\u201c\u5e27\u7f16\u53f7\u3001\u53d1\u9001\u7a97\u53e3 WT\u3001\u63a5\u6536\u7a97\u53e3 WR\u3001GBN\u3001SR\u3001\u505c\u6b62\u7b49\u5f85\u3001\u94fe\u8def\u5229\u7528\u7387\u201d<\/h3>\n\n\n\n<p>\u90a3\u57fa\u672c\u5c31\u662f\u6570\u636e\u94fe\u8def\u5c42\u53ef\u9760\u4f20\u8f93\u89c6\u89d2\u3002<\/p>\n\n\n\n<p>\u518d\u8fdb\u4e00\u6b65\u538b\u7f29\u6210\u4e00\u53e5\u53e3\u8bc0\uff1a<\/p>\n\n\n\n<p><strong>\u94fe\u8def\u5c42\u7a97\u53e3\u91cd\u5728\u5dee\u9519\u6062\u590d\uff0cTCP \u7a97\u53e3\u8fd8\u8981\u517c\u987e\u6d41\u91cf\u63a7\u5236\u548c\u62e5\u585e\u63a7\u5236\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5341\u4e09\u3001\u8fd9\u4e00\u90e8\u5206\u6700\u5bb9\u6613\u9519\u7684\u70b9\uff0c\u6700\u597d\u5355\u72ec\u8bb0\u4e00\u4e0b<\/h2>\n\n\n\n<p>\u7b2c\u4e00\uff0cUDP \u9762\u5411\u62a5\u6587\uff0c\u4fdd\u7559\u6d88\u606f\u8fb9\u754c\uff1bTCP \u9762\u5411\u5b57\u8282\u6d41\uff0c\u4e0d\u4fdd\u7559\u6d88\u606f\u8fb9\u754c\u3002<br>\u7b2c\u4e8c\uff0cTCP \u7684\u5e8f\u53f7\u548c\u786e\u8ba4\u53f7\u90fd\u662f\u6309\u5b57\u8282\u7f16\u53f7\uff0c\u4e0d\u662f\u6309\u62a5\u6587\u6bb5\u7f16\u53f7\u3002<br>\u7b2c\u4e09\uff0cSYN \u548c FIN \u5404\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\uff0c\u7eaf ACK \u4e0d\u6d88\u8017\u3002<br>\u7b2c\u56db\uff0cTCP \u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\u662f\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3\uff0c\u4f53\u73b0\u6d41\u91cf\u63a7\u5236\u3002<br>\u7b2c\u4e94\uff0c\u53d1\u9001\u7a97\u53e3\u771f\u6b63\u53d6\u51b3\u4e8e <code>min(rwnd, cwnd)<\/code>\u3002<br>\u7b2c\u516d\uff0cMSS \u6307 TCP \u6570\u636e\u90e8\u5206\u6700\u5927\u957f\u5ea6\uff0c\u4e0d\u542b TCP\/IP \u9996\u90e8\u3002<br>\u7b2c\u4e03\uff0cTCP \u7684\u7d2f\u8ba1\u786e\u8ba4\u673a\u5236\u770b\u8d77\u6765\u50cf GBN\uff0c\u4f46 TCP \u4e0d\u662f\u7b80\u5355\u7684 GBN\u3002<br>\u7b2c\u516b\uff0c\u4e09\u6b21\u63e1\u624b\u662f\u4e3a\u4e86\u53cc\u65b9\u90fd\u786e\u8ba4\u5f7c\u6b64\u7684\u53d1\u9001\u3001\u63a5\u6536\u80fd\u529b\uff1b\u56db\u6b21\u6325\u624b\u662f\u56e0\u4e3a TCP \u5168\u53cc\u5de5\uff0c\u4e24\u4e2a\u65b9\u5411\u8981\u5206\u522b\u5173\u95ed\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5341\u56db\u3001\u6700\u540e\u628a\u8fd9\u90e8\u5206\u538b\u7f29\u6210\u4e00\u7248\u8003\u524d\u901f\u8bb0<\/h2>\n\n\n\n<p>TCP \u4e0e UDP \u7684\u62a5\u6587\u533a\u522b\uff0c\u6700\u6838\u5fc3\u5c31\u662f\u4e00\u53e5\uff1a<\/p>\n\n\n\n<p><strong>UDP \u9762\u5411\u62a5\u6587\uff0c\u4fdd\u7559\u8fb9\u754c\uff1bTCP \u9762\u5411\u5b57\u8282\u6d41\uff0c\u4e0d\u4fdd\u7559\u8fb9\u754c\u3002<\/strong><\/p>\n\n\n\n<p>TCP \u62a5\u6587\u6bb5\u6807\u5fd7\u4f4d\uff0c\u5e38\u8003 6 \u4e2a\uff1a<\/p>\n\n\n\n<p><code>URG\u3001ACK\u3001PSH\u3001RST\u3001SYN\u3001FIN<\/code><\/p>\n\n\n\n<p>\u5176\u4e2d\u6700\u91cd\u8981\u7684\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>SYN<\/code>\uff1a\u5efa\u7acb\u8fde\u63a5\uff0c\u5360 1 \u4e2a\u5e8f\u53f7<\/li>\n\n\n\n<li><code>ACK<\/code>\uff1a\u786e\u8ba4\u6709\u6548\uff0c\u7eaf ACK \u4e0d\u5360\u5e8f\u53f7<\/li>\n\n\n\n<li><code>FIN<\/code>\uff1a\u91ca\u653e\u8fde\u63a5\uff0c\u5360 1 \u4e2a\u5e8f\u53f7<\/li>\n\n\n\n<li><code>RST<\/code>\uff1a\u5f02\u5e38\u590d\u4f4d<\/li>\n<\/ul>\n\n\n\n<p>\u7a97\u53e3\u5b57\u6bb5\u8868\u793a\uff1a<\/p>\n\n\n\n<p><strong>\u63a5\u6536\u65b9\u5f53\u524d\u8fd8\u80fd\u63a5\u6536\u591a\u5c11\u5b57\u8282\u3002<\/strong><\/p>\n\n\n\n<p>MSS \u8868\u793a\uff1a<\/p>\n\n\n\n<p><strong>TCP \u6570\u636e\u90e8\u5206\u6700\u5927\u957f\u5ea6\u3002<\/strong><\/p>\n\n\n\n<p>\u53d1\u9001\u7a97\u53e3\u53d6\u51b3\u4e8e\uff1a<\/p>\n\n\n\n<p><code>min(rwnd, cwnd)<\/code><\/p>\n\n\n\n<p>\u4e09\u6b21\u63e1\u624b\u8bb0\u6cd5\uff1a<\/p>\n\n\n\n<p><code>SYN \u2192 SYN+ACK \u2192 ACK<\/code><\/p>\n\n\n\n<p>\u56db\u6b21\u6325\u624b\u8bb0\u6cd5\uff1a<\/p>\n\n\n\n<p><code>FIN \u2192 ACK \u2192 FIN \u2192 ACK<\/code><\/p>\n\n\n\n<p>\u505a\u4e00\u5207\u63e1\u624b\u6325\u624b\u9898\uff0c\u53ea\u6293\u4e09\u6761\u89c4\u5219\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SYN \u52a0 1<\/li>\n\n\n\n<li>FIN \u52a0 1<\/li>\n\n\n\n<li>\u7eaf ACK \u4e0d\u52a0 1<\/li>\n\n\n\n<li>\u6570\u636e\u6309\u5b57\u8282\u6570\u63a8\u8fdb<\/li>\n<\/ul>\n\n\n\n<p>40Gb\/s \u4e0b 32 \u4f4d\u5e8f\u53f7\u7ed5\u56de\u65f6\u95f4\uff1a<\/p>\n\n\n\n<p><code>2^32 B \u00f7 (40\u00d710^9 \u00f7 8) B\/s \u2248 0.859 s<\/code><\/p>\n\n\n\n<p>TCP \u7a97\u53e3\u548c GBN \u7684\u5173\u7cfb\uff1a<\/p>\n\n\n\n<p><strong>\u601d\u60f3\u76f8\u4f3c\uff0c\u90fd\u662f\u6ed1\u52a8\u7a97\u53e3\uff1b\u4f46 TCP \u662f\u7aef\u5230\u7aef\u3001\u6309\u5b57\u8282\u3001\u517c\u987e\u6d41\u91cf\u63a7\u5236\u548c\u62e5\u585e\u63a7\u5236\uff0c\u4e0d\u80fd\u7b80\u5355\u7b49\u540c\u4e8e GBN\u3002<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">TCP \u9996\u90e8\u5b57\u6bb5\u9898\u3001\u63e1\u624b\u6325\u624b\u9898\u3001\u7a97\u53e3\u8ba1\u7b97\u9898\u7684\u505a\u9898\u6a21\u677f<\/h2>\n\n\n\n<p>\u524d\u9762\u628a TCP \u7684\u6838\u5fc3\u6982\u5ff5\u634b\u987a\u4e4b\u540e\uff0c\u771f\u6b63\u5230\u505a\u9898\u65f6\uff0c\u6700\u9700\u8981\u7684\u5176\u5b9e\u4e0d\u662f\u518d\u80cc\u4e00\u904d\u5b9a\u4e49\uff0c\u800c\u662f\u6709\u4e00\u5957\u80fd\u76f4\u63a5\u843d\u7b14\u3001\u76f4\u63a5\u63a8\u6570\u3001\u76f4\u63a5\u6392\u9664\u9519\u8bef\u9009\u9879\u7684\u6a21\u677f\u3002TCP \u8fd9\u4e00\u7ae0\u6700\u5178\u578b\u7684\u9898\uff0c\u57fa\u672c\u90fd\u53ef\u4ee5\u5f52\u5230\u4e09\u7c7b\uff1a\u9996\u90e8\u5b57\u6bb5\u8bc6\u522b\u9898\u3001\u63e1\u624b\u6325\u624b\u5206\u6790\u9898\u3001\u7a97\u53e3\u4e0e\u786e\u8ba4\u8ba1\u7b97\u9898\u3002\u8fd9\u4e09\u7c7b\u9898\u770b\u8d77\u6765\u4fe1\u606f\u91cf\u5f88\u5927\uff0c\u4f46\u771f\u6b63\u4e0a\u624b\u65f6\uff0c\u5224\u65ad\u8def\u5f84\u5176\u5b9e\u5f88\u56fa\u5b9a\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e00\u8282\u5c31\u4e13\u95e8\u628a\u8fd9\u4e09\u7c7b\u9898\u7684\u201c\u56fa\u5b9a\u505a\u6cd5\u201d\u5355\u72ec\u6574\u7406\u51fa\u6765\u3002\u540e\u9762\u590d\u4e60\u65f6\uff0c\u53ea\u8981\u628a\u6a21\u677f\u62ff\u51fa\u6765\u5957\uff0c\u5f88\u591a\u9898\u5c31\u4e0d\u4f1a\u518d\u4e71\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u3001TCP \u9996\u90e8\u5b57\u6bb5\u9898\u7684\u505a\u9898\u6a21\u677f<\/h3>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u6700\u5e38\u89c1\u7684\u51fa\u6cd5\uff0c\u662f\u7ed9\u51fa\u4e00\u4e2a\u573a\u666f\uff0c\u8ba9\u5224\u65ad\u5e94\u8be5\u4f7f\u7528\u54ea\u4e2a\u5b57\u6bb5\uff0c\u6216\u8005\u76f4\u63a5\u95ee\u67d0\u4e2a\u5b57\u6bb5\u7684\u4f5c\u7528\uff0c\u4e5f\u53ef\u80fd\u628a TCP \u548c UDP \u7684\u9996\u90e8\u653e\u5728\u4e00\u8d77\u6bd4\u8f83\u3002\u770b\u8d77\u6765\u50cf\u8bb0\u5fc6\u9898\uff0c\u4f46\u771f\u6b63\u60f3\u505a\u7a33\uff0c\u4e0d\u80fd\u6b7b\u8bb0\u786c\u80cc\uff0c\u800c\u662f\u8981\u6309\u201c\u8fd9\u4e2a\u5b57\u6bb5\u89e3\u51b3\u4ec0\u4e48\u95ee\u9898\u201d\u6765\u5206\u7c7b\u3002<\/p>\n\n\n\n<p>\u505a\u9996\u90e8\u5b57\u6bb5\u9898\u65f6\uff0c\u6211\u4e00\u822c\u5148\u4e0d\u6025\u7740\u770b\u9009\u9879\uff0c\u800c\u662f\u5148\u95ee\u81ea\u5df1\uff1a\u9898\u76ee\u95ee\u7684\u5230\u5e95\u662f\u4e0b\u9762\u54ea\u4e00\u7c7b\u80fd\u529b\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u7c7b\uff0c\u662f\u201c\u5bfb\u5740\u548c\u590d\u7528\u201d\u3002\u5982\u679c\u9898\u76ee\u95ee\u7684\u662f\u201c\u54ea\u4e2a\u8fdb\u7a0b\u548c\u54ea\u4e2a\u8fdb\u7a0b\u901a\u4fe1\u201d\u201c\u533a\u5206\u540c\u4e00\u4e3b\u673a\u4e0a\u7684\u4e0d\u540c\u5e94\u7528\u8fdb\u7a0b\u201d\uff0c\u90a3\u4f18\u5148\u60f3\u5230\u6e90\u7aef\u53e3\u548c\u76ee\u7684\u7aef\u53e3\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u7c7b\uff0c\u662f\u201c\u53ef\u9760\u4f20\u8f93\u548c\u6309\u5e8f\u4ea4\u4ed8\u201d\u3002\u5982\u679c\u9898\u76ee\u95ee\u7684\u662f\u201c\u54ea\u4e00\u90e8\u5206\u4fdd\u8bc1\u6709\u5e8f\u201d\u201c\u54ea\u4e00\u90e8\u5206\u8868\u793a\u53d1\u9001\u5b57\u8282\u7684\u4f4d\u7f6e\u201d\u201c\u786e\u8ba4\u5230\u4e86\u54ea\u91cc\u201d\uff0c\u90a3\u4f18\u5148\u60f3\u5230\u5e8f\u53f7\u548c\u786e\u8ba4\u53f7\u3002\u5e8f\u53f7\u8d1f\u8d23\u7ed9\u5b57\u8282\u7f16\u53f7\uff0c\u786e\u8ba4\u53f7\u8d1f\u8d23\u8bf4\u660e\u4e0b\u4e00\u6b21\u671f\u671b\u6536\u5230\u54ea\u4e2a\u5b57\u8282\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u7c7b\uff0c\u662f\u201c\u8fde\u63a5\u5efa\u7acb\u548c\u91ca\u653e\u201d\u3002\u5982\u679c\u9898\u76ee\u6d89\u53ca\u4e09\u6b21\u63e1\u624b\u3001\u56db\u6b21\u6325\u624b\u3001\u5f02\u5e38\u590d\u4f4d\uff0c\u90a3\u4f18\u5148\u60f3\u5230\u6807\u5fd7\u5b57\u6bb5\uff0c\u5c24\u5176\u662f SYN\u3001ACK\u3001FIN\u3001RST\u3002<\/p>\n\n\n\n<p>\u7b2c\u56db\u7c7b\uff0c\u662f\u201c\u6d41\u91cf\u63a7\u5236\u201d\u3002\u5982\u679c\u9898\u76ee\u95ee\u63a5\u6536\u65b9\u8fd8\u80fd\u6536\u591a\u5c11\u3001\u53d1\u9001\u65b9\u6700\u591a\u8fd8\u80fd\u53d1\u591a\u5c11\uff0c\u4f18\u5148\u60f3\u5230\u7a97\u53e3\u5b57\u6bb5\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e94\u7c7b\uff0c\u662f\u201c\u7d27\u6025\u6570\u636e\u548c\u7acb\u5373\u4ea4\u4ed8\u201d\u3002\u9898\u76ee\u51fa\u73b0\u201c\u7d27\u6025\u201d\u201c\u4f18\u5148\u5904\u7406\u201d\uff0c\u5bf9\u5e94 URG \u548c\u7d27\u6025\u6307\u9488\uff1b\u9898\u76ee\u51fa\u73b0\u201c\u5c3d\u5feb\u63d0\u4ea4\u5e94\u7528\u5c42\u201d\uff0c\u5bf9\u5e94 PSH\u3002<\/p>\n\n\n\n<p>\u7b2c\u516d\u7c7b\uff0c\u662f\u201c\u68c0\u9519\u201d\u3002\u5982\u679c\u9898\u76ee\u95ee\u9996\u90e8\u4e2d\u54ea\u4e2a\u5b57\u6bb5\u7528\u4e8e\u5dee\u9519\u68c0\u6d4b\uff0c\u60f3\u5230\u6821\u9a8c\u548c\u3002<\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u9996\u90e8\u5b57\u6bb5\u9898\u4e0d\u662f\u4e00\u5806\u96f6\u6563\u5b57\u6bb5\uff0c\u800c\u662f\u6309\u7167\u529f\u80fd\u4e00\u5757\u4e00\u5757\u8bb0\u3002\u8fd9\u6837\u505a\u9898\u65f6\uff0c\u5148\u5b9a\u4f4d\u529f\u80fd\uff0c\u518d\u6620\u5c04\u5b57\u6bb5\uff0c\u901f\u5ea6\u4f1a\u5feb\u5f88\u591a\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e8c\u3001TCP \u9996\u90e8\u5b57\u6bb5\u9898\u7684\u901f\u5224\u8868<\/h3>\n\n\n\n<p>\u4e3a\u4e86\u540e\u9762\u590d\u4e60\u66f4\u987a\uff0c\u6211\u628a\u6700\u5e38\u89c1\u5b57\u6bb5\u548c\u8003\u6cd5\u538b\u7f29\u6210\u4e00\u5f20\u8868\u3002\u8003\u8bd5\u65f6\u5f88\u591a\u9009\u9879\u5176\u5b9e\u90fd\u80fd\u9760\u8fd9\u5f20\u8868\u5feb\u901f\u6392\u9664\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u5b57\u6bb5<\/th><th>\u4f5c\u7528<\/th><th>\u9898\u76ee\u91cc\u5e38\u89c1\u8868\u8ff0<\/th><\/tr><\/thead><tbody><tr><td>\u6e90\u7aef\u53e3\u3001\u76ee\u7684\u7aef\u53e3<\/td><td>\u6807\u8bc6\u53d1\u9001\/\u63a5\u6536\u8fdb\u7a0b<\/td><td>\u8fdb\u7a0b\u590d\u7528\u4e0e\u5206\u7528\u3001\u7aef\u5230\u7aef\u903b\u8f91\u901a\u4fe1<\/td><\/tr><tr><td>\u5e8f\u53f7 seq<\/td><td>\u672c\u62a5\u6587\u6bb5\u6570\u636e\u90e8\u5206\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7<\/td><td>\u6309\u5b57\u8282\u7f16\u53f7\u3001\u53ef\u9760\u4f20\u8f93\u3001\u6709\u5e8f\u4ea4\u4ed8<\/td><\/tr><tr><td>\u786e\u8ba4\u53f7 ack<\/td><td>\u671f\u671b\u6536\u5230\u5bf9\u65b9\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7<\/td><td>\u786e\u8ba4\u3001\u7d2f\u8ba1\u786e\u8ba4\u3001\u6536\u5230\u54ea\u91cc\u4e3a\u6b62<\/td><\/tr><tr><td>\u6570\u636e\u504f\u79fb<\/td><td>TCP \u9996\u90e8\u957f\u5ea6<\/td><td>\u9996\u90e8\u591a\u957f\u3001\u6570\u636e\u4ece\u54ea\u91cc\u5f00\u59cb<\/td><\/tr><tr><td>\u6807\u5fd7\u4f4d<\/td><td>\u8fde\u63a5\u7ba1\u7406\u4e0e\u72b6\u6001\u63a7\u5236<\/td><td>SYN\u3001ACK\u3001FIN\u3001RST\u3001PSH\u3001URG<\/td><\/tr><tr><td>\u7a97\u53e3<\/td><td>\u63a5\u6536\u65b9\u5f53\u524d\u53ef\u63a5\u6536\u7684\u6570\u636e\u91cf<\/td><td>\u6d41\u91cf\u63a7\u5236\u3001\u63a5\u6536\u7f13\u5b58\u5269\u4f59\u7a7a\u95f4<\/td><\/tr><tr><td>\u6821\u9a8c\u548c<\/td><td>\u68c0\u6d4b\u5dee\u9519<\/td><td>\u5dee\u9519\u68c0\u6d4b<\/td><\/tr><tr><td>\u7d27\u6025\u6307\u9488<\/td><td>\u7d27\u6025\u6570\u636e\u672b\u5c3e\u4f4d\u7f6e<\/td><td>URG\u3001\u751f\u6548\u6761\u4ef6<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u7684\u5e38\u89c1\u9677\u9631\u6709\u4e24\u4e2a\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u9677\u9631\uff0c\u662f\u628a\u201c\u7a97\u53e3\u201d\u8bef\u4ee5\u4e3a\u662f\u53d1\u9001\u65b9\u8bf4\u4e86\u7b97\u3002\u5b9e\u9645\u4e0a TCP \u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\uff0c\u662f\u63a5\u6536\u65b9\u901a\u544a\u7ed9\u53d1\u9001\u65b9\u7684\uff0c\u8868\u793a\u201c\u6211\u8fd8\u80fd\u6536\u591a\u5c11\u201d\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u4e2a\u9677\u9631\uff0c\u662f\u628a\u201c\u786e\u8ba4\u53f7\u201d\u7406\u89e3\u6210\u201c\u5df2\u7ecf\u6536\u5230\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7\u201d\u3002\u66f4\u51c6\u786e\u7684\u8bf4\u6cd5\u5e94\u8be5\u662f\uff1a<strong>\u786e\u8ba4\u53f7\u8868\u793a\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7<\/strong>\u3002\u8fd9\u4e24\u4e2a\u8bf4\u6cd5\u770b\u8d77\u6765\u5f88\u50cf\uff0c\u4f46\u8003\u8bd5\u65f6\u5982\u679c\u8868\u8ff0\u4e25\u683c\uff0c\u6700\u597d\u7528\u540e\u8005\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e09\u3001\u9047\u5230 TCP \u9996\u90e8\u5b57\u6bb5\u9898\u65f6\uff0c\u56fa\u5b9a\u7b54\u9898\u987a\u5e8f\u600e\u4e48\u8d70<\/h3>\n\n\n\n<p>\u5982\u679c\u662f\u9009\u62e9\u9898\uff0c\u6211\u5efa\u8bae\u6309\u4e0b\u9762\u7684\u987a\u5e8f\u8fc7\u8111\u5b50\u3002<\/p>\n\n\n\n<p>\u5148\u770b\u9898\u5e72\u5173\u952e\u8bcd\u3002<br>\u51fa\u73b0\u201c\u8fde\u63a5\u5efa\u7acb\u201d\u770b SYN\u3002<br>\u51fa\u73b0\u201c\u8fde\u63a5\u91ca\u653e\u201d\u770b FIN\u3002<br>\u51fa\u73b0\u201c\u786e\u8ba4\u201d\u770b ACK \u548c\u786e\u8ba4\u53f7\u3002<br>\u51fa\u73b0\u201c\u6d41\u91cf\u63a7\u5236\u201d\u770b\u7a97\u53e3\u3002<br>\u51fa\u73b0\u201c\u590d\u4f4d\u201d\u770b RST\u3002<br>\u51fa\u73b0\u201c\u7d27\u6025\u201d\u770b URG\u3002<br>\u51fa\u73b0\u201c\u5c3d\u5feb\u4ea4\u4ed8\u201d\u770b PSH\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u662f\u7b80\u7b54\u9898\uff0c\u5c31\u4e0d\u8981\u53ea\u5199\u5b57\u6bb5\u540d\u79f0\uff0c\u800c\u5e94\u8be5\u5199\u6210\u201c\u5b57\u6bb5 + \u4f5c\u7528 + \u573a\u666f\u201d\u4e09\u8fde\u3002<\/p>\n\n\n\n<p>\u6bd4\u5982\u95ee\u7a97\u53e3\u5b57\u6bb5\u7684\u542b\u4e49\uff0c\u6700\u7a33\u7684\u5199\u6cd5\u4e0d\u662f\u53ea\u5199\u201c\u6d41\u91cf\u63a7\u5236\u201d\uff0c\u800c\u662f\u5199\uff1a<\/p>\n\n\n\n<p>\u201c\u7a97\u53e3\u5b57\u6bb5\u7531\u63a5\u6536\u65b9\u586b\u5199\uff0c\u8868\u793a\u63a5\u6536\u65b9\u5f53\u524d\u8fd8\u80fd\u63a5\u6536\u7684\u5b57\u8282\u6570\uff0c\u7528\u4e8e\u5b9e\u73b0 TCP \u7684\u6d41\u91cf\u63a7\u5236\uff0c\u9650\u5236\u53d1\u9001\u65b9\u7684\u53d1\u9001\u901f\u7387\u3002\u201d<\/p>\n\n\n\n<p>\u8fd9\u79cd\u5199\u6cd5\u5728\u8003\u8bd5\u91cc\u66f4\u5bb9\u6613\u62ff\u6ee1\u5206\uff0c\u56e0\u4e3a\u5b83\u4e0d\u662f\u53ea\u8bb0\u4f4f\u4e86\u540d\u8bcd\uff0c\u800c\u662f\u628a\u903b\u8f91\u5173\u7cfb\u5199\u5b8c\u6574\u4e86\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e09\u6b21\u63e1\u624b\u548c\u56db\u6b21\u6325\u624b\u9898\u7684\u505a\u9898\u6a21\u677f<\/h2>\n\n\n\n<p>\u63e1\u624b\u6325\u624b\u9898\u4e4b\u6240\u4ee5\u8ba9\u4eba\u5934\u75bc\uff0c\u6839\u672c\u539f\u56e0\u4e0d\u662f\u6b65\u9aa4\u591a\uff0c\u800c\u662f\u5b83\u540c\u65f6\u8003\u4e24\u4e2a\u65b9\u5411\u7684\u5e8f\u53f7\u53d8\u5316\u3002\u53ea\u8981\u80fd\u628a\u4e24\u4e2a\u65b9\u5411\u62c6\u5f00\uff0c\u9898\u76ee\u7acb\u523b\u5c31\u987a\u4e86\u3002<\/p>\n\n\n\n<p>\u6211\u505a\u8fd9\u7c7b\u9898\u65f6\uff0c\u56fa\u5b9a\u5148\u505a\u4e00\u4ef6\u4e8b\uff1a\u753b\u4e24\u6761\u5e8f\u53f7\u7ebf\u3002<\/p>\n\n\n\n<p>\u4e0a\u9762\u4e00\u6761\u5199\u5ba2\u6237\u7aef\u3002<br>\u4e0b\u9762\u4e00\u6761\u5199\u670d\u52a1\u5668\u3002<\/p>\n\n\n\n<p>\u7136\u540e\u6bcf\u6765\u4e00\u4e2a\u62a5\u6587\u6bb5\uff0c\u53ea\u68c0\u67e5\u56db\u4e2a\u4fe1\u606f\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u8c01\u53d1\u7684<\/li>\n\n\n\n<li>\u5e26\u4e86\u54ea\u4e9b\u6807\u5fd7\u4f4d<\/li>\n\n\n\n<li>\u6709\u6ca1\u6709\u6570\u636e<\/li>\n\n\n\n<li>\u5bf9\u65b9\u5e94\u8be5\u786e\u8ba4\u5230\u54ea\u91cc<\/li>\n<\/ol>\n\n\n\n<p>\u53ea\u8981\u575a\u6301\u8fd9\u6837\u505a\uff0c\u54ea\u6015\u9898\u76ee\u628a\u5305\u6570\u589e\u52a0\u3001\u628a\u6570\u636e\u5939\u5728\u4e2d\u95f4\uff0c\u751a\u81f3\u52a0\u5165 FIN\u3001SYN\u3001\u786e\u8ba4\u53f7\u6df7\u5408\uff0c\u4f60\u90fd\u4e0d\u4f1a\u4e71\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u3001\u63e1\u624b\u6325\u624b\u9898\u6700\u6838\u5fc3\u7684\u56db\u6761\u89c4\u5219<\/h3>\n\n\n\n<p>\u8fd9\u56db\u6761\u89c4\u5219\u6bd4\u80cc\u56fe\u66f4\u91cd\u8981\u3002\u51e0\u4e4e\u6240\u6709\u9898\u90fd\u9760\u5b83\u4eec\u63a8\u51fa\u7ed3\u679c\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u6761\uff0cTCP \u6309\u5b57\u8282\u7f16\u53f7\u3002<br>\u5e8f\u53f7\u4e0d\u662f\u62a5\u6587\u6bb5\u7f16\u53f7\uff0c\u800c\u662f\u5b57\u8282\u7f16\u53f7\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u6761\uff0cSYN \u548c FIN \u5404\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\u3002<br>\u53ea\u8981\u62a5\u6587\u6bb5\u5e26 SYN \u6216 FIN\uff0c\u5c31\u4f1a\u8ba9\u672c\u65b9\u5411\u5e8f\u53f7\u524d\u8fdb 1\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u6761\uff0c\u7eaf ACK \u4e0d\u6d88\u8017\u5e8f\u53f7\u3002<br>\u5982\u679c\u53ea\u662f\u786e\u8ba4\uff0c\u6ca1\u6709\u6570\u636e\uff0c\u4e5f\u6ca1\u6709 SYN\/FIN\uff0c\u90a3\u4e48 seq \u672c\u8eab\u4e0d\u56e0\u4e3a ACK \u800c\u524d\u8fdb\u3002<\/p>\n\n\n\n<p>\u7b2c\u56db\u6761\uff0cack \u8868\u793a\u201c\u671f\u671b\u6536\u5230\u5bf9\u65b9\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7\u201d\u3002<br>\u4e5f\u5c31\u662f\u8bf4\uff0c\u786e\u8ba4\u53f7 = \u5bf9\u65b9\u5df2\u6b63\u786e\u53d1\u9001\u5230\u7684\u6700\u540e\u4f4d\u7f6e + 1\u3002<\/p>\n\n\n\n<p>\u8fd9\u56db\u6761\u89c4\u5219\u57fa\u672c\u5c31\u662f\u6240\u6709\u63e1\u624b\u6325\u624b\u9898\u7684\u5e95\u5c42\u7b97\u6cd5\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e94\u3001\u4e09\u6b21\u63e1\u624b\u9898\u7684\u6807\u51c6\u6a21\u677f<\/h3>\n\n\n\n<p>\u8bbe\u5ba2\u6237\u7aef\u521d\u59cb\u5e8f\u53f7\u4e3a <code>x<\/code>\uff0c\u670d\u52a1\u5668\u521d\u59cb\u5e8f\u53f7\u4e3a <code>y``\u3002<\/code><\/p>\n\n\n\n<p>\u7b2c\u4e00\u6b65\uff0c\u5ba2\u6237\u7aef\u53d1\u8d77\u8fde\u63a5\uff1a<\/p>\n\n\n\n<p><code>SYN=1, seq=x<\/code><\/p>\n\n\n\n<p>\u56e0\u4e3a SYN \u5360\u4e00\u4e2a\u5e8f\u53f7\uff0c\u6240\u4ee5\u5ba2\u6237\u7aef\u540e\u7eed\u5e8f\u53f7\u4ece <code>x+1<\/code> \u5f00\u59cb\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u6b65\uff0c\u670d\u52a1\u5668\u540c\u610f\u8fde\u63a5\uff1a<\/p>\n\n\n\n<p><code>SYN=1, ACK=1, seq=y, ack=x+1<\/code><\/p>\n\n\n\n<p>\u8fd9\u91cc\u670d\u52a1\u5668\u786e\u8ba4\u4e86\u5ba2\u6237\u7aef\u7684 SYN\uff0c\u6240\u4ee5\u786e\u8ba4\u53f7\u662f <code>x+1<\/code>\u3002\u540c\u65f6\u670d\u52a1\u5668\u81ea\u5df1\u4e5f\u53d1\u4e86 SYN\uff0c\u56e0\u6b64\u670d\u52a1\u5668\u540e\u7eed\u5e8f\u53f7\u4ece <code>y+1<\/code> \u5f00\u59cb\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u6b65\uff0c\u5ba2\u6237\u7aef\u786e\u8ba4\uff1a<\/p>\n\n\n\n<p><code>ACK=1, seq=x+1, ack=y+1<\/code><\/p>\n\n\n\n<p>\u56e0\u4e3a\u8fd9\u662f\u7eaf ACK\uff0c\u6ca1\u6709\u6570\u636e\uff0c\u6ca1\u6709 SYN\/FIN\uff0c\u6240\u4ee5\u5ba2\u6237\u7aef\u7684 seq \u4ecd\u7136\u662f <code>x+1<\/code>\u3002<\/p>\n\n\n\n<p>\u628a\u8fd9\u4e09\u6b65\u538b\u7f29\u6210\u4e00\u4e2a\u56fa\u5b9a\u6a21\u677f\u5c31\u662f\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u6b21\u6570<\/th><th>\u65b9\u5411<\/th><th>\u6807\u5fd7<\/th><th>seq<\/th><th>ack<\/th><\/tr><\/thead><tbody><tr><td>1<\/td><td>C \u2192 S<\/td><td>SYN<\/td><td>x<\/td><td>\u65e0\u6548<\/td><\/tr><tr><td>2<\/td><td>S \u2192 C<\/td><td>SYN + ACK<\/td><td>y<\/td><td>x+1<\/td><\/tr><tr><td>3<\/td><td>C \u2192 S<\/td><td>ACK<\/td><td>x+1<\/td><td>y+1<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u4ee5\u540e\u53ea\u8981\u9898\u76ee\u4e00\u51fa\u73b0\u63e1\u624b\uff0c\u76f4\u63a5\u628a\u8fd9\u4e2a\u8868\u9ed8\u5199\u51fa\u6765\uff0c\u518d\u6309\u9898\u76ee\u7ed9\u7684\u5177\u4f53\u6570\u5b57\u4ee3\u8fdb\u53bb\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u516d\u3001\u56db\u6b21\u6325\u624b\u9898\u7684\u6807\u51c6\u6a21\u677f<\/h3>\n\n\n\n<p>\u8bbe\u4e3b\u52a8\u5173\u95ed\u65b9 A\uff0c\u521d\u59cb\u5173\u95ed\u65f6\u8be5\u65b9\u5411\u5f53\u524d\u5e8f\u53f7\u4e3a <code>u<\/code>\uff1b\u88ab\u52a8\u5173\u95ed\u65b9 B \u5f53\u524d\u5e8f\u53f7\u4e3a <code>v<\/code>\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u6b65\uff0cA \u53d1 FIN\uff1a<\/p>\n\n\n\n<p><code>FIN=1, seq=u<\/code><\/p>\n\n\n\n<p>\u56e0\u4e3a FIN \u5360\u4e00\u4e2a\u5e8f\u53f7\uff0c\u6240\u4ee5 A \u540e\u7eed\u5e8f\u53f7\u4ece <code>u+1<\/code> \u5f00\u59cb\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u6b65\uff0cB \u56de ACK\uff1a<\/p>\n\n\n\n<p><code>ACK=1, seq=v, ack=u+1<\/code><\/p>\n\n\n\n<p>\u6ce8\u610f\u8fd9\u91cc\u901a\u5e38\u662f\u7eaf ACK\uff0c\u6240\u4ee5 B \u7684 seq \u4e0d\u56e0\u4e3a ACK \u6539\u53d8\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u6b65\uff0cB \u81ea\u5df1\u4e5f\u53d1 FIN\uff1a<\/p>\n\n\n\n<p><code>FIN=1, ACK=1, seq=w, ack=u+1<\/code><\/p>\n\n\n\n<p>\u5982\u679c B \u5728\u7b2c\u4e8c\u6b21\u548c\u7b2c\u4e09\u6b21\u4e4b\u95f4\u6ca1\u6709\u518d\u53d1\u9001\u6570\u636e\uff0c\u90a3\u4e48\u5e38\u76f4\u63a5\u6709 <code>w=v<\/code>\u3002<br>\u5982\u679c\u4e2d\u95f4\u53d1\u8fc7\u6570\u636e\uff0c\u90a3 <code>w<\/code> \u5c31\u5e94\u7b49\u4e8e\u53d1\u5b8c\u90a3\u4e9b\u6570\u636e\u540e\u7684\u65b0\u5e8f\u53f7\u3002<\/p>\n\n\n\n<p>\u7b2c\u56db\u6b65\uff0cA \u56de ACK\uff1a<\/p>\n\n\n\n<p><code>ACK=1, seq=u+1, ack=w+1<\/code><\/p>\n\n\n\n<p>\u8fd9\u4e00\u6b65\u7eaf ACK\uff0c\u4e0d\u518d\u989d\u5916\u6d88\u8017\u5e8f\u53f7\u3002<\/p>\n\n\n\n<p>\u6807\u51c6\u6a21\u677f\u53ef\u4ee5\u8bb0\u6210\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u6b21\u6570<\/th><th>\u65b9\u5411<\/th><th>\u6807\u5fd7<\/th><th>seq<\/th><th>ack<\/th><\/tr><\/thead><tbody><tr><td>1<\/td><td>A \u2192 B<\/td><td>FIN<\/td><td>u<\/td><td>\u65e7\u503c\u6216\u65e0\u5173<\/td><\/tr><tr><td>2<\/td><td>B \u2192 A<\/td><td>ACK<\/td><td>v<\/td><td>u+1<\/td><\/tr><tr><td>3<\/td><td>B \u2192 A<\/td><td>FIN + ACK<\/td><td>w<\/td><td>u+1<\/td><\/tr><tr><td>4<\/td><td>A \u2192 B<\/td><td>ACK<\/td><td>u+1<\/td><td>w+1<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u6700\u5bb9\u6613\u9519\u7684\u5730\u65b9\uff0c\u5c31\u662f\u7b2c\u4e8c\u6b65\u548c\u7b2c\u4e09\u6b65\u91cc B \u7684 seq\u3002\u5f88\u591a\u4eba\u4f1a\u673a\u68b0\u5730\u628a\u7b2c\u4e8c\u6b65 ACK \u5f53\u6210\u4e5f\u5360\u4e00\u4e2a\u5e8f\u53f7\uff0c\u8fd9\u662f\u9519\u8bef\u7684\u3002\u7eaf ACK \u4e0d\u5360\u5e8f\u53f7\uff0c\u6240\u4ee5\u5982\u679c\u4e2d\u95f4\u6ca1\u53d1\u6570\u636e\uff0c\u90a3\u4e48\u7b2c\u4e8c\u6b65\u548c\u7b2c\u4e09\u6b65\u7684\u8d77\u59cb seq \u53ef\u4ee5\u4e00\u6837\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e03\u3001\u63e1\u624b\u6325\u624b\u9898\u7684\u4e07\u80fd\u63a8\u9898\u6b65\u9aa4<\/h3>\n\n\n\n<p>\u4ee5\u540e\u78b0\u5230\u4efb\u4f55 TCP \u63e1\u624b\u6325\u624b\u9898\uff0c\u4e0d\u7ba1\u5b83\u662f\u9009\u62e9\u9898\u8fd8\u662f\u5927\u9898\uff0c\u90fd\u53ef\u4ee5\u7528\u4e0b\u9762\u8fd9\u4e2a\u987a\u5e8f\u3002<\/p>\n\n\n\n<p>\u5148\u5199\u6e05\u521d\u59cb\u5e8f\u53f7\u3002<br>\u5982\u679c\u9898\u76ee\u7ed9\u4e86 <code>ISN=100<\/code>\u3001<code>seq=8000<\/code> \u4e4b\u7c7b\uff0c\u5148\u5728\u4e24\u6761\u7ebf\u5404\u81ea\u6807\u597d\u3002<\/p>\n\n\n\n<p>\u7136\u540e\u6309\u62a5\u6587\u6bb5\u987a\u5e8f\u63a8\u8fdb\u3002<br>\u6bcf\u770b\u5230\u4e00\u4e2a\u62a5\u6587\u6bb5\uff0c\u5c31\u5224\u65ad\u5b83\u662f\u5426\u5305\u542b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SYN<\/li>\n\n\n\n<li>FIN<\/li>\n\n\n\n<li>\u6570\u636e<\/li>\n\n\n\n<li>\u7eaf ACK<\/li>\n<\/ul>\n\n\n\n<p>\u63a5\u7740\u66f4\u65b0\u672c\u65b9\u5411\u5e8f\u53f7\u3002<br>\u66f4\u65b0\u89c4\u5219\u975e\u5e38\u673a\u68b0\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5e26 SYN\uff1a\u672c\u65b9\u5411 +1<\/li>\n\n\n\n<li>\u5e26 FIN\uff1a\u672c\u65b9\u5411 +1<\/li>\n\n\n\n<li>\u5e26\u6570\u636e\uff1a\u672c\u65b9\u5411 + \u6570\u636e\u5b57\u8282\u6570<\/li>\n\n\n\n<li>\u7eaf ACK\uff1a\u672c\u65b9\u5411\u4e0d\u53d8<\/li>\n<\/ul>\n\n\n\n<p>\u6700\u540e\u66f4\u65b0\u5bf9\u65b9\u786e\u8ba4\u53f7\u3002<br>\u786e\u8ba4\u53f7\u59cb\u7ec8\u5199\u6210\uff1a<\/p>\n\n\n\n<p><code>ack = \u671f\u671b\u6536\u5230\u7684\u5bf9\u65b9\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7<\/code><\/p>\n\n\n\n<p>\u53ea\u8981\u575a\u6301\u201c\u5148\u66f4\u65b0\u53d1\u9001\u65b9 seq\uff0c\u518d\u66f4\u65b0\u63a5\u6536\u65b9 ack\u201d\uff0c\u8fd9\u7c7b\u9898\u4f1a\u975e\u5e38\u7a33\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u7a97\u53e3\u8ba1\u7b97\u9898\u7684\u505a\u9898\u6a21\u677f<\/h2>\n\n\n\n<p>TCP \u7a97\u53e3\u9898\u6bd4\u63e1\u624b\u6325\u624b\u66f4\u5bb9\u6613\u8ba9\u4eba\u4e71\uff0c\u56e0\u4e3a\u5b83\u540c\u65f6\u53ef\u80fd\u6df7\u7740\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u63a5\u6536\u7a97\u53e3 rwnd<\/li>\n\n\n\n<li>\u62e5\u585e\u7a97\u53e3 cwnd<\/li>\n\n\n\n<li>\u53d1\u9001\u7a97\u53e3<\/li>\n\n\n\n<li>\u5df2\u53d1\u9001\u672a\u786e\u8ba4\u6570\u636e<\/li>\n\n\n\n<li>\u786e\u8ba4\u53f7<\/li>\n\n\n\n<li>\u53ef\u7ee7\u7eed\u53d1\u9001\u7684\u6570\u636e\u91cf<\/li>\n<\/ul>\n\n\n\n<p>\u5982\u679c\u6ca1\u6709\u6a21\u677f\uff0c\u5f88\u5bb9\u6613\u6bcf\u4e2a\u8bcd\u90fd\u8ba4\u8bc6\uff0c\u4f46\u6574\u9053\u9898\u7b97\u4e0d\u660e\u767d\u3002<\/p>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u6700\u91cd\u8981\u7684\u662f\u5148\u628a\u201c\u7a97\u53e3\u201d\u62c6\u6210\u4e09\u4e2a\u5c42\u6b21\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u5c42\u6b21\uff0c\u662f\u63a5\u6536\u65b9\u7a97\u53e3 <code>rwnd<\/code>\uff0c\u5b83\u8868\u793a\u63a5\u6536\u65b9\u8fd8\u80fd\u6536\u591a\u5c11\u3002<br>\u7b2c\u4e8c\u4e2a\u5c42\u6b21\uff0c\u662f\u62e5\u585e\u7a97\u53e3 <code>cwnd<\/code>\uff0c\u5b83\u8868\u793a\u5f53\u524d\u7f51\u7edc\u5141\u8bb8\u53d1\u9001\u65b9\u53d1\u591a\u5c11\u3002<br>\u7b2c\u4e09\u4e2a\u5c42\u6b21\uff0c\u662f\u53d1\u9001\u65b9\u5b9e\u9645\u53ef\u7528\u7a97\u53e3\uff0c\u5b83\u7531\u524d\u4e24\u8005\u8f83\u5c0f\u503c\u51b3\u5b9a\uff0c\u518d\u6263\u9664\u5df2\u53d1\u9001\u672a\u786e\u8ba4\u90e8\u5206\u3002<\/p>\n\n\n\n<p>\u771f\u6b63\u505a\u9898\u65f6\uff0c\u5148\u56fa\u5b9a\u8bb0\u4f4f\u4e00\u4e2a\u603b\u516c\u5f0f\uff1a<\/p>\n\n\n\n<p><code>\u53d1\u9001\u7a97\u53e3\u4e0a\u9650 = min(rwnd, cwnd)<\/code><\/p>\n\n\n\n<p>\u7136\u540e\u518d\u8bb0\uff1a<\/p>\n\n\n\n<p><code>\u5f53\u524d\u8fd8\u80fd\u53d1\u9001\u7684\u6570\u636e\u91cf = \u53d1\u9001\u7a97\u53e3\u4e0a\u9650 - \u5df2\u53d1\u9001\u672a\u786e\u8ba4\u7684\u6570\u636e\u91cf<\/code><\/p>\n\n\n\n<p>\u53ea\u8981\u9898\u76ee\u6709\u7a97\u53e3\u3001\u6709\u786e\u8ba4\u53f7\u3001\u6709\u5df2\u53d1\u672a\u786e\u8ba4\u5b57\u8282\u6570\uff0c\u57fa\u672c\u90fd\u662f\u6309\u8fd9\u4e2a\u601d\u8def\u7b97\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u516b\u3001\u7a97\u53e3\u9898\u91cc\u51e0\u4e2a\u540d\u8bcd\u7684\u56fa\u5b9a\u7406\u89e3<\/h3>\n\n\n\n<p>\u4e3a\u4e86\u9632\u6b62\u540e\u9762\u4e00\u770b\u5230\u9898\u5e72\u5c31\u88ab\u7ed5\u6655\uff0c\u6700\u597d\u5148\u628a\u51e0\u4e2a\u8bcd\u9489\u6b7b\u3002<\/p>\n\n\n\n<p>\u201c\u53d1\u9001\u7a97\u53e3\u201d\u4e0d\u662f\u201c\u5df2\u7ecf\u53d1\u9001\u51fa\u53bb\u7684\u6570\u636e\u201d\uff0c\u800c\u662f\u201c\u5141\u8bb8\u53d1\u9001\u4f46\u5c1a\u672a\u786e\u8ba4\u7684\u5e8f\u53f7\u8303\u56f4\u201d\u3002<\/p>\n\n\n\n<p>\u201c\u53ef\u7528\u53d1\u9001\u7a97\u53e3\u201d\u624d\u662f\u6b64\u523b\u8fd8\u80fd\u7ee7\u7eed\u53d1\u51fa\u53bb\u7684\u90e8\u5206\u3002<\/p>\n\n\n\n<p>\u201c\u63a5\u6536\u7a97\u53e3\u201d\u662f\u63a5\u6536\u65b9\u901a\u544a\u7684\u5269\u4f59\u7f13\u5b58\u7a7a\u95f4\u3002<\/p>\n\n\n\n<p>\u201c\u786e\u8ba4\u53f7\u201d\u8868\u793a\u63a5\u6536\u65b9\u76ee\u524d\u6309\u5e8f\u6536\u5230\u4e86\u54ea\u91cc\uff0c\u56e0\u6b64\u4f1a\u51b3\u5b9a\u53d1\u9001\u7a97\u53e3\u5de6\u8fb9\u754c\u80fd\u5426\u53f3\u79fb\u3002<\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u7a97\u53e3\u9898\u672c\u8d28\u4e0a\u662f\u5728\u95ee\u4e24\u4ef6\u4e8b\uff1a<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u53d1\u9001\u65b9\u7406\u8bba\u4e0a\u6700\u591a\u80fd\u5360\u7528\u591a\u5927\u7a97\u53e3\u3002<br>\u7b2c\u4e8c\uff0c\u5728\u8fd9\u4e2a\u7a97\u53e3\u91cc\uff0c\u5df2\u7ecf\u7528\u4e86\u591a\u5c11\uff0c\u8fd8\u5269\u591a\u5c11\u53ef\u53d1\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e5d\u3001\u7a97\u53e3\u8ba1\u7b97\u9898\u7684\u6807\u51c6\u6b65\u9aa4<\/h3>\n\n\n\n<p>\u4ee5\u540e\u53ea\u8981\u78b0\u5230 TCP \u7a97\u53e3\u9898\uff0c\u5efa\u8bae\u56fa\u5b9a\u6309\u4e0b\u9762\u56db\u6b65\u8d70\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u6b65\uff0c\u627e <code>rwnd<\/code> \u548c <code>cwnd<\/code>\u3002<br>\u5982\u679c\u9898\u76ee\u53ea\u7ed9\u6d41\u91cf\u63a7\u5236\u4fe1\u606f\uff0c\u6ca1\u6709\u62e5\u585e\u63a7\u5236\uff0c\u90a3\u5c31\u9ed8\u8ba4\u53d1\u9001\u7a97\u53e3\u4e3b\u8981\u770b <code>rwnd<\/code>\u3002<br>\u5982\u679c\u4e24\u4e2a\u90fd\u7ed9\uff0c\u5c31\u5148\u53d6\u6700\u5c0f\u503c\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\u6b65\uff0c\u627e\u201c\u5df2\u53d1\u9001\u672a\u786e\u8ba4\u7684\u6570\u636e\u91cf\u201d\u3002<br>\u8fd9\u4e2a\u91cf\u901a\u5e38\u53ef\u4ee5\u901a\u8fc7\u201c\u5df2\u53d1\u9001\u5230\u54ea\u4e2a\u5e8f\u53f7\u201d\u201c\u5df2\u786e\u8ba4\u5230\u54ea\u4e2a\u5e8f\u53f7\u201d\u6765\u6c42\u3002<\/p>\n\n\n\n<p>\u4e00\u822c\u53ef\u5199\u6210\uff1a<\/p>\n\n\n\n<p><code>\u5df2\u53d1\u9001\u672a\u786e\u8ba4 = \u5df2\u53d1\u9001\u6700\u540e\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7 - \u5df2\u786e\u8ba4\u5230\u7684\u524d\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7<\/code><\/p>\n\n\n\n<p>\u5982\u679c\u9898\u76ee\u76f4\u63a5\u7ed9\u201c\u8fd8\u6709\u591a\u5c11\u672a\u786e\u8ba4\u6570\u636e\u201d\uff0c\u90a3\u66f4\u7b80\u5355\uff0c\u76f4\u63a5\u7528\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\u6b65\uff0c\u6c42\u5f53\u524d\u8fd8\u80fd\u53d1\u9001\u7684\u6570\u636e\u91cf\u3002<br>\u516c\u5f0f\u5c31\u662f\uff1a<\/p>\n\n\n\n<p><code>\u8fd8\u80fd\u53d1\u9001 = min(rwnd, cwnd) - \u5df2\u53d1\u9001\u672a\u786e\u8ba4<\/code><\/p>\n\n\n\n<p>\u7b2c\u56db\u6b65\uff0c\u68c0\u67e5\u7ed3\u679c\u662f\u5426\u5408\u7406\u3002<br>\u5982\u679c\u7b97\u51fa\u6765\u662f\u8d1f\u6570\uff0c\u8bf4\u660e\u6b64\u523b\u4e0d\u80fd\u7ee7\u7eed\u53d1\uff1b<br>\u5982\u679c\u7b97\u51fa\u6765\u662f 0\uff0c\u8bf4\u660e\u7a97\u53e3\u5df2\u6ee1\uff1b<br>\u5982\u679c\u5927\u4e8e 0\uff0c\u8bf4\u660e\u8fd8\u53ef\u4ee5\u7ee7\u7eed\u53d1\u8fd9\u4e48\u591a\u5b57\u8282\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u6a21\u677f\u9002\u5408\u7edd\u5927\u591a\u6570\u7a97\u53e3\u9009\u62e9\u9898\u548c\u8ba1\u7b97\u9898\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u3001\u4e00\u4e2a\u6700\u5e38\u89c1\u7684\u7a97\u53e3\u9898\u578b\uff0c\u600e\u6837\u5957\u6a21\u677f<\/h3>\n\n\n\n<p>\u6bd4\u5982\u9898\u76ee\u8bf4\uff1a<\/p>\n\n\n\n<p>\u201c\u53d1\u9001\u65b9\u5df2\u53d1\u9001 3000B\uff0c\u5df2\u786e\u8ba4 2000B\uff0c\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3\u4e3a 4000B\uff0c\u62e5\u585e\u7a97\u53e3\u4e3a 5000B\uff0c\u95ee\u5f53\u524d\u8fd8\u80fd\u53d1\u9001\u591a\u5c11\u5b57\u8282\uff1f\u201d<\/p>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u770b\u8d77\u6765\u5b57\u5f88\u591a\uff0c\u4f46\u5c31\u662f\u673a\u68b0\u5957\u516c\u5f0f\u3002<\/p>\n\n\n\n<p>\u5148\u6c42\u53d1\u9001\u7a97\u53e3\u4e0a\u9650\uff1a<\/p>\n\n\n\n<p><code>min(rwnd, cwnd) = min(4000, 5000) = 4000B<\/code><\/p>\n\n\n\n<p>\u518d\u6c42\u5df2\u53d1\u9001\u672a\u786e\u8ba4\uff1a<\/p>\n\n\n\n<p><code>3000 - 2000 = 1000B<\/code><\/p>\n\n\n\n<p>\u4e8e\u662f\u5f53\u524d\u8fd8\u80fd\u53d1\u9001\uff1a<\/p>\n\n\n\n<p><code>4000 - 1000 = 3000B<\/code><\/p>\n\n\n\n<p>\u8fd9\u5c31\u662f\u7b54\u6848\u3002<\/p>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u771f\u6b63\u96be\u7684\u5730\u65b9\uff0c\u4e0d\u5728\u7b97\uff0c\u800c\u5728\u5206\u6e05\u201c\u5df2\u53d1\u9001\u201d\u548c\u201c\u5df2\u786e\u8ba4\u201d\u4e0d\u662f\u4e00\u56de\u4e8b\u3002\u5f88\u591a\u4eba\u4f1a\u628a\u5df2\u7ecf\u786e\u8ba4\u7684\u4e5f\u7b97\u8fdb\u5360\u7528\u7a97\u53e3\u91cc\uff0c\u5bfc\u81f4\u7ed3\u679c\u504f\u5c0f\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e00\u3001\u786e\u8ba4\u53f7\u4e0e\u7a97\u53e3\u7ed3\u5408\u9898\uff0c\u6700\u5bb9\u6613\u9519\u5728\u54ea<\/h3>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u7ecf\u5e38\u4f1a\u95ee\uff1a<\/p>\n\n\n\n<p>\u201c\u63a5\u6536\u65b9\u53d1\u9001\u786e\u8ba4\u53f7 ack=5001\uff0c\u8fd9\u8868\u793a\u4ec0\u4e48\uff1f\u201d<\/p>\n\n\n\n<p>\u6807\u51c6\u7406\u89e3\u662f\uff1a<\/p>\n\n\n\n<p>\u8fd9\u8868\u793a\u63a5\u6536\u65b9\u5df2\u7ecf\u6309\u5e8f\u6536\u5230\u4e86\u7f16\u53f7\u5230 5000 \u4e3a\u6b62\u7684\u6570\u636e\uff0c\u4e0b\u4e00\u6b21\u5e0c\u671b\u53d1\u9001\u65b9\u4ece 5001 \u5f00\u59cb\u53d1\u9001\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u8fd9\u65f6\u53c8\u7ed9\u51fa\u63a5\u6536\u7a97\u53e3\u4e3a 2000B\uff0c\u90a3\u4e48\u542b\u4e49\u5c31\u662f\uff1a<\/p>\n\n\n\n<p>\u53d1\u9001\u65b9\u63a5\u4e0b\u6765\u6700\u591a\u53ef\u4ee5\u5728 5001 \u5f00\u59cb\u7684\u57fa\u7840\u4e0a\uff0c\u518d\u5360\u7528 2000B \u7684\u63a5\u6536\u7a97\u53e3\u8303\u56f4\u3002<\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u786e\u8ba4\u53f7\u51b3\u5b9a\u5de6\u8fb9\u754c\uff0c\u7a97\u53e3\u5927\u5c0f\u51b3\u5b9a\u53f3\u8fb9\u754c\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u601d\u60f3\u7279\u522b\u91cd\u8981\u3002\u4ee5\u540e\u770b\u5230\u201cack + \u7a97\u53e3\u201d\u653e\u5728\u4e00\u8d77\uff0c\u5c31\u8981\u60f3\u5230\uff1a<strong>ack \u5b9a\u8d77\u70b9\uff0cwindow \u5b9a\u5bbd\u5ea6\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e8c\u3001\u7a97\u53e3\u9898\u3001\u63e1\u624b\u9898\u3001\u9996\u90e8\u5b57\u6bb5\u9898\u4e4b\u95f4\u5176\u5b9e\u662f\u8fde\u7740\u7684<\/h3>\n\n\n\n<p>\u5f88\u591a\u4eba\u590d\u4e60\u65f6\u628a\u8fd9\u4e09\u7c7b\u9898\u5206\u5f00\u8bb0\uff0c\u7ed3\u679c\u8d8a\u8bb0\u8d8a\u6563\u3002\u5b9e\u9645\u4e0a\uff0c\u5b83\u4eec\u4e4b\u95f4\u662f\u4e00\u6761\u7ebf\u3002<\/p>\n\n\n\n<p>\u9996\u90e8\u5b57\u6bb5\u9898\uff0c\u89e3\u51b3\u7684\u662f\u201c\u6bcf\u4e2a\u5b57\u6bb5\u5e72\u4ec0\u4e48\u201d\u3002<br>\u63e1\u624b\u6325\u624b\u9898\uff0c\u8003\u7684\u662f\u201cseq\u3001ack\u3001SYN\u3001FIN \u5982\u4f55\u8054\u52a8\u201d\u3002<br>\u7a97\u53e3\u8ba1\u7b97\u9898\uff0c\u8003\u7684\u662f\u201cack\u3001window\u3001\u5df2\u53d1\u9001\u6570\u636e\u5982\u4f55\u8054\u52a8\u201d\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4ece\u6839\u4e0a\u8bf4\uff0c\u8fd9\u4e00\u7ae0\u771f\u6b63\u53cd\u590d\u51fa\u73b0\u7684\u6838\u5fc3\u53ea\u6709\u56db\u4e2a\u91cf\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>seq<\/code><\/li>\n\n\n\n<li><code>ack<\/code><\/li>\n\n\n\n<li>\u6807\u5fd7\u4f4d<\/li>\n\n\n\n<li>\u7a97\u53e3<\/li>\n<\/ul>\n\n\n\n<p>\u505a\u9898\u65f6\u53ea\u8981\u76ef\u4f4f\u8fd9\u56db\u4e2a\u91cf\uff0c\u9898\u5e72\u518d\u957f\uff0c\u4e5f\u4e0d\u4f1a\u5b8c\u5168\u5931\u63a7\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u6700\u540e\u538b\u7f29\u6210\u4e00\u7248\u201c\u8003\u573a\u901f\u7528\u6a21\u677f\u201d<\/h2>\n\n\n\n<p>TCP \u9996\u90e8\u5b57\u6bb5\u9898\uff0c\u5148\u6309\u529f\u80fd\u5206\u7c7b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7aef\u53e3\uff1a\u8fdb\u7a0b\u590d\u7528\u4e0e\u5206\u7528<\/li>\n\n\n\n<li>seq\uff1a\u6309\u5b57\u8282\u7f16\u53f7<\/li>\n\n\n\n<li>ack\uff1a\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7<\/li>\n\n\n\n<li>\u6807\u5fd7\u4f4d\uff1a\u8fde\u63a5\u5efa\u7acb\u3001\u91ca\u653e\u3001\u590d\u4f4d\u3001\u7d27\u6025\u3001\u63a8\u9001<\/li>\n\n\n\n<li>\u7a97\u53e3\uff1a\u63a5\u6536\u65b9\u8fd8\u80fd\u63a5\u6536\u591a\u5c11\u5b57\u8282<\/li>\n\n\n\n<li>\u6821\u9a8c\u548c\uff1a\u5dee\u9519\u68c0\u6d4b<\/li>\n<\/ul>\n\n\n\n<p>\u63e1\u624b\u6325\u624b\u9898\uff0c\u53ea\u8bb0\u56db\u6761\u89c4\u5219\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>SYN \u5360 1 \u4e2a\u5e8f\u53f7<\/li>\n\n\n\n<li>FIN \u5360 1 \u4e2a\u5e8f\u53f7<\/li>\n\n\n\n<li>\u7eaf ACK \u4e0d\u5360\u5e8f\u53f7<\/li>\n\n\n\n<li>\u6570\u636e\u6309\u5b57\u8282\u6570\u63a8\u8fdb\u5e8f\u53f7<\/li>\n<\/ul>\n\n\n\n<p>\u505a\u9898\u987a\u5e8f\u56fa\u5b9a\u4e3a\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u753b\u4e24\u6761\u5e8f\u53f7\u7ebf<\/li>\n\n\n\n<li>\u770b\u8c01\u53d1<\/li>\n\n\n\n<li>\u770b\u6709\u6ca1\u6709 SYN\/FIN\/\u6570\u636e<\/li>\n\n\n\n<li>\u66f4\u65b0\u672c\u65b9\u5411 seq<\/li>\n\n\n\n<li>\u7528\u201c\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7\u201d\u5199 ack<\/li>\n<\/ol>\n\n\n\n<p>\u7a97\u53e3\u9898\u53ea\u8bb0\u4e24\u4e2a\u516c\u5f0f\uff1a<\/p>\n\n\n\n<p><code>\u53d1\u9001\u7a97\u53e3\u4e0a\u9650 = min(rwnd, cwnd)<\/code><\/p>\n\n\n\n<p><code>\u5f53\u524d\u8fd8\u80fd\u53d1\u9001 = min(rwnd, cwnd) - \u5df2\u53d1\u9001\u672a\u786e\u8ba4<\/code><\/p>\n\n\n\n<p>\u518d\u914d\u4e00\u53e5\u7406\u89e3\uff1a<\/p>\n\n\n\n<p><strong>ack \u51b3\u5b9a\u5de6\u8fb9\u754c\uff0cwindow \u51b3\u5b9a\u7a97\u53e3\u5bbd\u5ea6\u3002<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">TCP \u8fd9\u7ae0\u6700\u5bb9\u6613\u51fa\u9519\u7684\u5178\u578b\u9677\u9631\u6e05\u5355<\/h2>\n\n\n\n<p>TCP \u8fd9\u4e00\u7ae0\u5f88\u5178\u578b\u7684\u4e00\u4e2a\u95ee\u9898\u662f\uff0c\u5355\u770b\u6bcf\u4e2a\u77e5\u8bc6\u70b9\u90fd\u4e0d\u7b97\u96be\uff1a\u4e09\u6b21\u63e1\u624b\u80fd\u80cc\uff0c\u56db\u6b21\u6325\u624b\u4e5f\u89c1\u8fc7\uff0c\u7a97\u53e3\u5b57\u6bb5\u3001\u786e\u8ba4\u53f7\u3001MSS\u3001\u5e8f\u53f7\u8fd9\u4e9b\u6982\u5ff5\u4e5f\u90fd\u8ba4\u8bc6\u3002\u4f46\u4e00\u5230\u505a\u9898\uff0c\u5c24\u5176\u662f\u4e00\u9053\u9898\u91cc\u540c\u65f6\u51fa\u73b0\u591a\u4e2a\u5b57\u6bb5\u3001\u591a\u6b21\u4ea4\u4e92\u3001\u591a\u4e2a\u62a5\u6587\u6bb5\u7684\u65f6\u5019\uff0c\u5c31\u7279\u522b\u5bb9\u6613\u4e71\u3002\u5f88\u591a\u9519\u8bef\u5e76\u4e0d\u662f\u4e0d\u4f1a\uff0c\u800c\u662f\u201c\u4f3c\u61c2\u975e\u61c2\u201d\uff0c\u6700\u540e\u5728\u7ec6\u8282\u5904\u4e22\u5206\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e00\u8282\u5c31\u4e13\u95e8\u628a TCP \u91cc\u6700\u5bb9\u6613\u51fa\u9519\u7684\u9677\u9631\u96c6\u4e2d\u6574\u7406\u4e00\u4e0b\u3002\u540e\u9762\u590d\u4e60\u65f6\uff0c\u5149\u770b\u8fd9\u4efd\u201c\u5751\u70b9\u6e05\u5355\u201d\uff0c\u5f80\u5f80\u6bd4\u518d\u770b\u4e00\u904d\u6982\u5ff5\u66f4\u6709\u7528\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u3001\u628a TCP \u770b\u6210\u201c\u9762\u5411\u62a5\u6587\u201d\u800c\u4e0d\u662f\u201c\u9762\u5411\u5b57\u8282\u6d41\u201d<\/h3>\n\n\n\n<p>\u8fd9\u662f TCP \u6700\u6839\u672c\u3001\u4e5f\u6700\u5bb9\u6613\u5728\u540e\u9762\u53cd\u590d\u8fde\u9501\u51fa\u9519\u7684\u5730\u65b9\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u5728\u521a\u5b66 TCP \u65f6\uff0c\u4f1a\u4e0d\u81ea\u89c9\u5730\u628a\u5b83\u60f3\u6210\u201c\u548c UDP \u4e00\u6837\uff0c\u4e5f\u662f\u4e00\u4e2a\u4e00\u4e2a\u6570\u636e\u5305\u5730\u4f20\uff0c\u53ea\u4e0d\u8fc7\u66f4\u53ef\u9760\u201d\u3002\u8fd9\u4e2a\u7406\u89e3\u5f88\u5bb9\u6613\u5bfc\u81f4\u540e\u9762\u5f88\u591a\u9898\u90fd\u505a\u504f\uff0c\u56e0\u4e3a TCP \u548c UDP \u5728\u4f20\u8f93\u5bf9\u8c61\u4e0a\u5c31\u4e0d\u662f\u4e00\u56de\u4e8b\u3002<\/p>\n\n\n\n<p>UDP \u9762\u5411\u62a5\u6587\uff0c\u5e94\u7528\u5c42\u4ea4\u7ed9\u5b83\u4e00\u6761\u62a5\u6587\uff0c\u5b83\u57fa\u672c\u5c31\u6309\u8fd9\u6761\u62a5\u6587\u53d1\uff0c\u63a5\u6536\u65f6\u4e5f\u6309\u4e00\u6761\u5b8c\u6574\u62a5\u6587\u4ea4\u7ed9\u5e94\u7528\u5c42\uff0c\u56e0\u6b64 UDP \u4fdd\u7559\u62a5\u6587\u8fb9\u754c\u3002<\/p>\n\n\n\n<p>TCP \u9762\u5411\u5b57\u8282\u6d41\u3002\u5e94\u7528\u5c42\u5199\u5165\u7684\u662f\u4e00\u4e32\u5b57\u8282\uff0cTCP \u53ea\u8d1f\u8d23\u628a\u8fd9\u4e32\u5b57\u8282\u53ef\u9760\u3001\u6309\u5e8f\u9001\u5230\u5bf9\u65b9\uff0c\u5e76\u4e0d\u4fdd\u7559\u201c\u8fd9\u90e8\u5206\u539f\u6765\u662f\u4e00\u6b21 write \u53d1\u7684\uff0c\u90a3\u90e8\u5206\u539f\u6765\u662f\u53e6\u4e00\u6b21 write \u53d1\u7684\u201d\u8fd9\u79cd\u8fb9\u754c\u4fe1\u606f\u3002\u4e00\u6b21\u5e94\u7528\u5c42\u53d1\u9001\uff0c\u53ef\u80fd\u88ab\u62c6\u6210\u591a\u4e2a\u62a5\u6587\u6bb5\uff1b\u591a\u6b21\u5e94\u7528\u5c42\u53d1\u9001\uff0c\u4e5f\u53ef\u80fd\u88ab\u5408\u5e76\u8fdb\u4e00\u4e2a\u62a5\u6587\u6bb5\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u5730\u65b9\u4e00\u65e6\u6ca1\u60f3\u6e05\u695a\uff0c\u540e\u9762\u5c31\u5bb9\u6613\u72af\u4e24\u4e2a\u5178\u578b\u9519\u8bef\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u9519\u8bef\uff0c\u662f\u8bef\u4ee5\u4e3a TCP \u7684\u5e8f\u53f7\u5bf9\u5e94\u201c\u7b2c\u51e0\u4e2a\u62a5\u6587\u6bb5\u201d\u3002\u5176\u5b9e TCP \u7684\u5e8f\u53f7\u5bf9\u5e94\u7684\u662f<strong>\u5b57\u8282\u4f4d\u7f6e<\/strong>\u3002<br>\u7b2c\u4e8c\u4e2a\u9519\u8bef\uff0c\u662f\u770b\u5230\u201c\u53d1\u9001\u4e86\u4e00\u4e2a TCP \u62a5\u6587\u6bb5\u201d\uff0c\u5c31\u60f3\u5f53\u7136\u5730\u8ba4\u4e3a\u63a5\u6536\u65b9\u4e5f\u201c\u4e00\u6b21\u6536\u5230\u4e00\u4e2a\u5b8c\u6574\u5355\u4f4d\u201d\u3002\u5b9e\u9645\u4e0a\uff0c\u63a5\u6536\u65b9\u62ff\u5230\u7684\u662f\u5b57\u8282\u6d41\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u8fd9\u4e00\u7ae0\u6700\u5148\u8981\u56fa\u5b9a\u7684\u4e00\u53e5\u8bdd\u5c31\u662f\uff1a<\/p>\n\n\n\n<p><strong>TCP \u6309\u5b57\u8282\u7f16\u53f7\uff0c\u9762\u5411\u5b57\u8282\u6d41\uff1bUDP \u6309\u62a5\u6587\u7ec4\u7ec7\uff0c\u9762\u5411\u62a5\u6587\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e8c\u3001\u628a seq \u5f53\u6210\u201c\u62a5\u6587\u6bb5\u7f16\u53f7\u201d\uff0c\u800c\u4e0d\u662f\u201c\u5b57\u8282\u7f16\u53f7\u201d<\/h3>\n\n\n\n<p>\u8fd9\u662f TCP \u8ba1\u7b97\u9898\u91cc\u6700\u5e38\u89c1\u7684\u9519\u8bef\u4e4b\u4e00\u3002<\/p>\n\n\n\n<p>TCP \u9996\u90e8\u4e2d\u7684\u5e8f\u53f7 <code>seq<\/code>\uff0c\u4e0d\u662f\u201c\u8fd9\u662f\u7b2c\u51e0\u4e2a\u62a5\u6587\u6bb5\u201d\uff0c\u800c\u662f\uff1a<\/p>\n\n\n\n<p><strong>\u672c\u62a5\u6587\u6bb5\u6570\u636e\u90e8\u5206\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u53e5\u8bdd\u5fc5\u987b\u54ac\u5f97\u5f88\u6b7b\uff0c\u56e0\u4e3a\u5b83\u4f1a\u76f4\u63a5\u5f71\u54cd\u4e09\u7c7b\u9898\uff1a<\/p>\n\n\n\n<p>\u7b2c\u4e00\u7c7b\uff0c\u662f\u63e1\u624b\u6325\u624b\u9898\u3002<br>\u7b2c\u4e8c\u7c7b\uff0c\u662f\u5e26\u6570\u636e\u7684\u786e\u8ba4\u53f7\u8ba1\u7b97\u9898\u3002<br>\u7b2c\u4e09\u7c7b\uff0c\u662f\u5e8f\u53f7\u7ed5\u56de\u9898\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u4e00\u4e2a TCP \u62a5\u6587\u6bb5\u643a\u5e26\u4e86 100B \u6570\u636e\uff0c\u8d77\u59cb\u5e8f\u53f7\u662f 3001\uff0c\u90a3\u4e48\u5b83\u8986\u76d6\u7684\u6570\u636e\u8303\u56f4\u5c31\u662f 3001 \u5230 3100\uff0c\u4e0b\u4e00\u4e2a\u62a5\u6587\u6bb5\u82e5\u7d27\u63a5\u7740\u53d1\uff0c\u5e8f\u53f7\u5c31\u5e94\u4ece 3101 \u5f00\u59cb\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u9519\u5728\u628a\u201c\u53d1\u4e86\u4e00\u4e2a\u62a5\u6587\u6bb5\u201d\u5c31\u5f53\u6210\u201c\u5e8f\u53f7 +1\u201d\u3002\u8fd9\u5728 TCP \u4e2d\u662f\u9519\u8bef\u7684\u3002\u53ea\u6709\u4e24\u79cd\u7279\u6b8a\u63a7\u5236\u4f4d\u4f1a\u65e0\u8bba\u662f\u5426\u5e26\u6570\u636e\u90fd\u989d\u5916\u5360\u4e00\u4e2a\u5e8f\u53f7\uff0c\u90a3\u5c31\u662f SYN \u548c FIN\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u5e8f\u53f7\u63a8\u8fdb\u7684\u771f\u6b63\u89c4\u5219\u5e94\u8be5\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d1\u6570\u636e\uff1a\u5e8f\u53f7\u52a0\u6570\u636e\u5b57\u8282\u6570<\/li>\n\n\n\n<li>\u53d1 SYN\uff1a\u5e8f\u53f7\u52a0 1<\/li>\n\n\n\n<li>\u53d1 FIN\uff1a\u5e8f\u53f7\u52a0 1<\/li>\n\n\n\n<li>\u7eaf ACK\uff1a\u5e8f\u53f7\u4e0d\u53d8<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u4e2a\u89c4\u5219\u662f TCP \u6574\u7ae0\u6700\u6838\u5fc3\u7684\u8ba1\u7b97\u5e95\u5ea7\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e09\u3001\u628a ack \u7406\u89e3\u6210\u201c\u6536\u5230\u4e86\u54ea\u4e2a\u7f16\u53f7\u201d\uff0c\u800c\u4e0d\u662f\u201c\u4e0b\u4e00\u4e2a\u60f3\u6536\u54ea\u4e2a\u7f16\u53f7\u201d<\/h3>\n\n\n\n<p>\u786e\u8ba4\u53f7\u4e5f\u662f TCP \u91cc\u975e\u5e38\u5bb9\u6613\u534a\u61c2\u4e0d\u61c2\u7684\u70b9\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u5728\u8111\u4e2d\u4f1a\u628a\u5b83\u7406\u89e3\u4e3a\u201c\u6211\u6536\u5230\u4e86\u7f16\u53f7 1000 \u7684\u6570\u636e\uff0c\u6240\u4ee5 ACK=1000\u201d\u3002\u8fd9\u79cd\u7406\u89e3\u5728\u76f4\u89c9\u4e0a\u4f3c\u4e4e\u4e5f\u8bf4\u5f97\u8fc7\u53bb\uff0c\u4f46\u4e25\u683c\u6765\u8bf4\u662f\u4e0d\u5bf9\u7684\u3002<\/p>\n\n\n\n<p>TCP \u7684 ack \u7684\u51c6\u786e\u542b\u4e49\u662f\uff1a<\/p>\n\n\n\n<p><strong>\u63a5\u6536\u65b9\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7\u3002<\/strong><\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u5982\u679c ack=1001\uff0c\u771f\u6b63\u7684\u542b\u4e49\u4e0d\u662f\u201c\u6211\u53ea\u6536\u5230\u4e86 1001\u201d\uff0c\u800c\u662f\uff1a<\/p>\n\n\n\n<p>\u201c\u5230 1000 \u4e3a\u6b62\u7684\u5b57\u8282\u6211\u90fd\u5df2\u7ecf\u6309\u5e8f\u6536\u5230\u4e86\uff0c\u4e0b\u4e00\u6b21\u8bf7\u4ece 1001 \u5f00\u59cb\u53d1\u3002\u201d<\/p>\n\n\n\n<p>\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48 TCP \u4f7f\u7528\u7d2f\u8ba1\u786e\u8ba4\u3002\u786e\u8ba4\u53f7\u4e00\u65e6\u524d\u8fdb\u5230\u67d0\u4e2a\u4f4d\u7f6e\uff0c\u5c31\u8868\u793a\u5728\u6b64\u4e4b\u524d\u7684\u6309\u5e8f\u6570\u636e\u90fd\u5df2\u7ecf\u786e\u8ba4\u4e86\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u5751\u6700\u5bb9\u6613\u5728\u5e26\u6570\u636e\u7684\u9898\u91cc\u51fa\u95ee\u9898\u3002\u6bd4\u5982\u4e00\u4e2a\u62a5\u6587\u6bb5\u8d77\u59cb seq=500\uff0c\u6570\u636e\u957f\u5ea6 200B\uff0c\u90a3\u4e48\u5b83\u8986\u76d6\u5b57\u8282\u7f16\u53f7 500 \u5230 699\u3002\u5982\u679c\u5bf9\u65b9\u6b63\u786e\u6536\u5230\u5e76\u786e\u8ba4\uff0c\u90a3\u4e48\u8fd4\u56de\u7684 ack \u5e94\u8be5\u662f 700\uff0c\u800c\u4e0d\u662f 699\uff0c\u4e5f\u4e0d\u662f 500\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u53ef\u4ee5\u628a ack \u6c38\u8fdc\u7ffb\u8bd1\u6210\u4e00\u53e5\u56fa\u5b9a\u7684\u8bdd\uff1a<\/p>\n\n\n\n<p><strong>ACK \u4e0d\u662f\u201c\u6536\u5230\u54ea\u201d\uff0c\u800c\u662f\u201c\u4e0b\u6b21\u8be5\u4ece\u54ea\u5f00\u59cb\u53d1\u201d\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u3001\u5fd8\u8bb0 SYN \u548c FIN \u90fd\u4f1a\u5360\u7528\u4e00\u4e2a\u5e8f\u53f7<\/h3>\n\n\n\n<p>\u8fd9\u53ef\u4ee5\u8bf4\u662f\u8fde\u63a5\u7ba1\u7406\u9898\u91cc\u6700\u81f4\u547d\u7684\u5751\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u77e5\u9053\u6570\u636e\u4f1a\u8ba9\u5e8f\u53f7\u524d\u8fdb\uff0c\u5374\u5fd8\u4e86 SYN \u548c FIN \u4e5f\u4f1a\u5404\u5360\u4e00\u4e2a\u5e8f\u53f7\u3002\u4e8e\u662f\u4e09\u6b21\u63e1\u624b\u3001\u56db\u6b21\u6325\u624b\u7684 seq \u548c ack \u4e00\u7b97\u5c31\u9519\u3002<\/p>\n\n\n\n<p>\u5fc5\u987b\u7262\u7262\u8bb0\u4f4f\uff1a<\/p>\n\n\n\n<p><strong>SYN \u5360 1 \u4e2a\u5e8f\u53f7\uff0cFIN \u5360 1 \u4e2a\u5e8f\u53f7\uff0c\u7eaf ACK \u4e0d\u5360\u5e8f\u53f7\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u53e5\u8bdd\u662f\u505a\u63e1\u624b\u6325\u624b\u9898\u7684\u7b2c\u4e00\u94c1\u5f8b\u3002<\/p>\n\n\n\n<p>\u6bd4\u5982\u5ba2\u6237\u7aef\u53d1\u9001\uff1a<\/p>\n\n\n\n<p><code>SYN=1, seq=100<\/code><\/p>\n\n\n\n<p>\u90a3\u4e48\u670d\u52a1\u5668\u786e\u8ba4\u65f6\u5c31\u5fc5\u987b\u5199\uff1a<\/p>\n\n\n\n<p><code>ack=101<\/code><\/p>\n\n\n\n<p>\u56e0\u4e3a SYN \u672c\u8eab\u4e5f\u5360\u7528\u4e86\u4e00\u4e2a\u5e8f\u53f7\u3002<\/p>\n\n\n\n<p>\u518d\u6bd4\u5982 A \u53d1\u9001\uff1a<\/p>\n\n\n\n<p><code>FIN=1, seq=800<\/code><\/p>\n\n\n\n<p>\u90a3\u4e48 B \u786e\u8ba4\u65f6\u5e94\u5199\uff1a<\/p>\n\n\n\n<p><code>ack=801<\/code><\/p>\n\n\n\n<p>\u8fd9\u548c\u201c\u5e26\u4e86 1B \u6570\u636e\u6240\u4ee5 +1\u201d\u5728\u5f62\u5f0f\u4e0a\u5f88\u50cf\uff0c\u4f46\u6765\u6e90\u4e0d\u540c\u3002\u5b83\u4e0d\u662f\u6570\u636e\u957f\u5ea6\uff0c\u800c\u662f\u63a7\u5236\u4f4d FIN \u672c\u8eab\u5360\u4e86\u4e00\u4e2a\u5e8f\u53f7\u3002<\/p>\n\n\n\n<p>\u4ee5\u540e\u53ea\u8981\u770b\u5230\u9898\u76ee\u4e2d\u51fa\u73b0 SYN \u6216 FIN\uff0c\u5c31\u5e94\u8be5\u7acb\u523b\u5728\u8111\u4e2d\u4eae\u8d77\u4e00\u4e2a\u63d0\u9192\uff1a<\/p>\n\n\n\n<p><strong>\u8fd9\u91cc\u8981 +1\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e94\u3001\u8bef\u4ee5\u4e3a\u201c\u51e1\u662f ACK \u90fd\u4f1a\u8ba9 seq \u52a0 1\u201d<\/h3>\n\n\n\n<p>\u8fd9\u901a\u5e38\u662f\u4e0a\u4e00\u4e2a\u5751\u7684\u8fde\u5e26\u9519\u8bef\u3002<\/p>\n\n\n\n<p>\u56e0\u4e3a\u5f88\u591a\u4eba\u80cc\u63e1\u624b\u6325\u624b\u65f6\uff0c\u53ea\u770b\u5230\u4e00\u8fde\u4e32\u201c101\u3001102\u3001103\u201d\u4e4b\u7c7b\u7684\u6570\u5b57\u53d8\u5316\uff0c\u5c31\u8bef\u4ee5\u4e3a ACK \u4e5f\u4f1a\u63a8\u52a8 seq \u524d\u8fdb\u3002\u5b9e\u9645\u4e0a\uff0cACK \u53ea\u662f\u8868\u793a\u786e\u8ba4\u53f7\u5b57\u6bb5\u6709\u6548\uff0c\u7eaf ACK \u672c\u8eab\u4e0d\u5360\u7528\u5e8f\u53f7\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u5982\u679c\u4e00\u4e2a\u62a5\u6587\u6bb5\u53ea\u662f\uff1a<\/p>\n\n\n\n<p><code>ACK=1, seq=x, ack=y<\/code><\/p>\n\n\n\n<p>\u800c\u6ca1\u6709\u6570\u636e\u3001\u6ca1\u6709 SYN\u3001\u6ca1\u6709 FIN\uff0c\u90a3\u4e48\u8fd9\u4e2a\u62a5\u6587\u6bb5\u53d1\u5b8c\u4ee5\u540e\uff0c\u53d1\u9001\u65b9\u81ea\u5df1\u7684\u5e8f\u53f7\u4ecd\u7136\u8fd8\u662f x\uff0c\u4e0d\u4f1a\u56e0\u4e3a\u201c\u53d1\u4e86\u4e00\u4e2a ACK\u201d\u5c31\u81ea\u52a8\u53d8\u6210 x+1\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u5751\u5728\u56db\u6b21\u6325\u624b\u7b2c\u4e8c\u6b65\u548c\u7b2c\u56db\u6b65\u6700\u5e38\u89c1\u3002<\/p>\n\n\n\n<p>A \u53d1 FIN \u540e\uff0cB \u4f1a\u5148\u56de\u4e00\u4e2a ACK\uff0c\u8fd9\u4e2a ACK \u5982\u679c\u6ca1\u6709\u5e26\u6570\u636e\uff0c\u90a3\u4e48 B \u7684 seq \u4e0d\u53d8\u3002\u540e\u9762 B \u518d\u53d1 FIN \u65f6\uff0c\u5982\u679c\u4e2d\u95f4\u4e5f\u6ca1\u53d1\u6570\u636e\uff0c\u90a3\u4e48\u5b83\u53d1 FIN \u65f6\u7684 seq \u548c\u521a\u624d\u90a3\u4e2a ACK \u7684 seq \u5f80\u5f80\u662f\u4e00\u6837\u7684\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u9898\u5c31\u4e13\u95e8\u5229\u7528\u8fd9\u4e00\u70b9\u8bbe\u9677\u9631\uff0c\u8ba9\u4eba\u8bef\u628a ACK \u5f53\u6210\u4e5f\u6d88\u8017\u5e8f\u53f7\uff0c\u6700\u540e seq \u5168\u7ebf\u9519\u4f4d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u516d\u3001\u628a TCP \u9996\u90e8\u4e2d\u7684\u201c\u7a97\u53e3\u201d\u8bef\u5f53\u6210\u53d1\u9001\u65b9\u81ea\u5df1\u7684\u5269\u4f59\u53d1\u9001\u80fd\u529b<\/h3>\n\n\n\n<p>TCP \u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\u5f88\u5bb9\u6613\u671b\u6587\u751f\u4e49\uff0c\u4ee5\u4e3a\u201c\u7a97\u53e3\u201d\u5c31\u662f\u53d1\u9001\u65b9\u80fd\u53d1\u591a\u5c11\u3002\u5176\u5b9e\u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\uff0c\u662f<strong>\u63a5\u6536\u65b9\u901a\u544a\u7ed9\u53d1\u9001\u65b9\u7684\u7a97\u53e3<\/strong>\uff0c\u4e5f\u5c31\u662f\u63a5\u6536\u65b9\u5f53\u524d\u8fd8\u80fd\u63a5\u6536\u591a\u5c11\u5b57\u8282\u3002<\/p>\n\n\n\n<p>\u6362\u53e5\u8bdd\u8bf4\uff0c\u5b83\u4e0d\u662f\u53d1\u9001\u65b9\u81ea\u8a00\u81ea\u8bed\u5199\u8fdb\u53bb\u7684\uff0c\u800c\u662f\u63a5\u6536\u65b9\u544a\u8bc9\u5bf9\u65b9\uff1a<\/p>\n\n\n\n<p>\u201c\u6211\u8fd9\u8fb9\u63a5\u6536\u7f13\u5b58\u8fd8\u6709\u8fd9\u4e48\u591a\u7a7a\u95f4\uff0c\u4f60\u6700\u591a\u8fd8\u80fd\u5f80\u6211\u8fd9\u91cc\u538b\u8fd9\u4e48\u591a\u5b57\u8282\u3002\u201d<\/p>\n\n\n\n<p>\u6240\u4ee5\u8fd9\u4e2a\u5b57\u6bb5\u53cd\u6620\u7684\u662f<strong>\u6d41\u91cf\u63a7\u5236<\/strong>\uff0c\u7ea6\u675f\u7684\u662f\u53d1\u9001\u65b9\u7684\u53d1\u9001\u901f\u5ea6\uff0c\u4f9d\u636e\u7684\u662f\u63a5\u6536\u65b9\u7684\u63a5\u6536\u80fd\u529b\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u9898\u91cc\u4f1a\u95ee\u201c\u7a97\u53e3\u5b57\u6bb5\u7684\u542b\u4e49\u662f\u4ec0\u4e48\u201d\uff0c\u6700\u7a33\u7684\u7b54\u6cd5\u4e0d\u662f\u53ea\u5199\u201cTCP \u7684\u7a97\u53e3\u5927\u5c0f\u201d\uff0c\u800c\u662f\u5199\uff1a<\/p>\n\n\n\n<p><strong>\u7a97\u53e3\u5b57\u6bb5\u8868\u793a\u63a5\u6536\u65b9\u5f53\u524d\u53ef\u63a5\u6536\u7684\u6570\u636e\u91cf\uff0c\u7528\u4e8e\u901a\u77e5\u53d1\u9001\u65b9\u8fdb\u884c\u6d41\u91cf\u63a7\u5236\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u6837\u8868\u610f\u6700\u5b8c\u6574\uff0c\u4e5f\u6700\u4e0d\u5bb9\u6613\u6df7\u6210\u201c\u53d1\u9001\u65b9\u7a97\u53e3\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e03\u3001\u4ee5\u4e3a\u53d1\u9001\u7a97\u53e3\u53ea\u7531 rwnd \u51b3\u5b9a\uff0c\u5fd8\u4e86\u8fd8\u6709 cwnd<\/h3>\n\n\n\n<p>\u5982\u679c\u53ea\u5b66\u4e86\u6d41\u91cf\u63a7\u5236\uff0c\u5f88\u591a\u4eba\u4f1a\u89c9\u5f97\u201c\u7a97\u53e3\u5927\u5c0f\u5c31\u662f\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3 rwnd\u201d\u3002\u8fd9\u5728\u53ea\u8ba8\u8bba\u6d41\u91cf\u63a7\u5236\u7684\u9898\u76ee\u91cc\u4e0d\u7b97\u9519\uff0c\u4f46\u5982\u679c\u9898\u76ee\u628a\u62e5\u585e\u63a7\u5236\u4e5f\u5e26\u8fdb\u6765\uff0c\u8fd9\u4e2a\u7b54\u6848\u5c31\u4e0d\u5b8c\u6574\u4e86\u3002<\/p>\n\n\n\n<p>TCP \u53d1\u9001\u65b9\u771f\u6b63\u7684\u53d1\u9001\u7a97\u53e3\u4e0a\u9650\uff0c\u5e94\u8be5\u53d6\uff1a<\/p>\n\n\n\n<p><code>min(rwnd, cwnd)<\/code><\/p>\n\n\n\n<p>\u5176\u4e2d\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>rwnd<\/code> \u53cd\u6620\u63a5\u6536\u65b9\u63a5\u6536\u80fd\u529b<\/li>\n\n\n\n<li><code>cwnd<\/code> \u53cd\u6620\u5f53\u524d\u7f51\u7edc\u62e5\u585e\u72b6\u51b5<\/li>\n<\/ul>\n\n\n\n<p>\u6240\u4ee5\u53d1\u9001\u65b9\u4e0d\u662f\u201c\u60f3\u53d1\u591a\u5c11\u5c31\u53d1\u591a\u5c11\u201d\uff0c\u4e5f\u4e0d\u662f\u201c\u53ea\u8981\u63a5\u6536\u65b9\u88c5\u5f97\u4e0b\u5c31\u884c\u201d\uff0c\u800c\u662f\u65e2\u4e0d\u80fd\u628a\u63a5\u6536\u65b9\u6491\u7206\uff0c\u4e5f\u4e0d\u80fd\u628a\u7f51\u7edc\u6253\u7206\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u70b9\u7ecf\u5e38\u5728\u9009\u62e9\u9898\u91cc\u8003\u8868\u8ff0\u7684\u5b8c\u6574\u6027\u3002<br>\u5982\u679c\u9898\u76ee\u53ea\u5728\u8bb2\u6d41\u91cf\u63a7\u5236\uff0c\u53ef\u4ee5\u8bf4\u53d1\u9001\u7a97\u53e3\u53d7\u63a5\u6536\u65b9\u7a97\u53e3\u5f71\u54cd\uff1b<br>\u5982\u679c\u9898\u76ee\u660e\u786e\u628a\u62e5\u585e\u63a7\u5236\u4e5f\u7eb3\u5165\u6761\u4ef6\uff0c\u5c31\u5fc5\u987b\u5199\u5b8c\u6574\uff1a<\/p>\n\n\n\n<p><strong>\u53d1\u9001\u7a97\u53e3\u7531\u63a5\u6536\u7a97\u53e3\u548c\u62e5\u585e\u7a97\u53e3\u4e2d\u8f83\u5c0f\u8005\u51b3\u5b9a\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u516b\u3001\u628a\u201c\u53d1\u9001\u7a97\u53e3\u5927\u5c0f\u201d\u548c\u201c\u5f53\u524d\u8fd8\u80fd\u7ee7\u7eed\u53d1\u9001\u7684\u6570\u636e\u91cf\u201d\u6df7\u4e3a\u4e00\u8c08<\/h3>\n\n\n\n<p>\u8fd9\u662f\u7a97\u53e3\u8ba1\u7b97\u9898\u91cc\u7279\u522b\u5bb9\u6613\u7cca\u6d82\u7684\u5730\u65b9\u3002<\/p>\n\n\n\n<p>\u201c\u53d1\u9001\u7a97\u53e3\u5927\u5c0f\u201d\u901a\u5e38\u662f\u8bf4\u53d1\u9001\u65b9\u7406\u8bba\u4e0a\u5141\u8bb8\u5360\u7528\u7684\u7a97\u53e3\u8303\u56f4\uff0c\u5e38\u7531 <code>min(rwnd, cwnd)<\/code> \u51b3\u5b9a\u3002<br>\u4f46\u201c\u5f53\u524d\u8fd8\u80fd\u7ee7\u7eed\u53d1\u9001\u591a\u5c11\u201d\uff0c\u5e76\u4e0d\u7b49\u4e8e\u8fd9\u4e2a\u7a97\u53e3\u4e0a\u9650\uff0c\u56e0\u4e3a\u7a97\u53e3\u91cc\u53ef\u80fd\u5df2\u7ecf\u88c5\u4e86\u4e00\u90e8\u5206\u201c\u5df2\u53d1\u9001\u4f46\u672a\u786e\u8ba4\u7684\u6570\u636e\u201d\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u771f\u6b63\u80fd\u518d\u53d1\u591a\u5c11\uff0c\u5e94\u8be5\u662f\uff1a<\/p>\n\n\n\n<p><code>\u5f53\u524d\u53ef\u53d1\u9001\u91cf = min(rwnd, cwnd) - \u5df2\u53d1\u9001\u672a\u786e\u8ba4\u6570\u636e\u91cf<\/code><\/p>\n\n\n\n<p>\u8fd9\u4e24\u4e2a\u6982\u5ff5\u5fc5\u987b\u5206\u5f00\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u9898\u91cc\u7ed9\u51fa\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u63a5\u6536\u7a97\u53e3 5000B<\/li>\n\n\n\n<li>\u62e5\u585e\u7a97\u53e3 6000B<\/li>\n\n\n\n<li>\u5df2\u53d1\u9001\u672a\u786e\u8ba4 2000B<\/li>\n<\/ul>\n\n\n\n<p>\u7136\u540e\u95ee\u201c\u5f53\u524d\u8fd8\u80fd\u53d1\u591a\u5c11\u201d\u3002<br>\u8fd9\u65f6\u7b54\u6848\u4e0d\u662f 5000B\uff0c\u800c\u662f\uff1a<\/p>\n\n\n\n<p><code>5000 - 2000 = 3000B<\/code><\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u7a97\u53e3\u4e0a\u9650\u662f 5000B\uff0c\u4f46\u91cc\u9762\u5df2\u6709 2000B \u5728\u201c\u5360\u4f4d\u201d\uff0c\u5269\u4f59\u53ef\u53d1\u53ea\u6709 3000B\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u770b\u5230\u7a97\u53e3\u9898\uff0c\u5148\u522b\u6025\u7740\u4ee3\u516c\u5f0f\uff0c\u4e00\u5b9a\u5148\u95ee\u81ea\u5df1\uff1a<br>\u9898\u76ee\u95ee\u7684\u662f\u201c\u7a97\u53e3\u4e0a\u9650\u201d\uff0c\u8fd8\u662f\u201c\u6b64\u523b\u8fd8\u80fd\u53d1\u591a\u5c11\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e5d\u3001\u770b\u5230\u786e\u8ba4\u53f7\u5c31\u53ea\u4f1a\u673a\u68b0\u76f8\u51cf\uff0c\u4e0d\u7406\u89e3\u201c\u5de6\u8fb9\u754c\u201d\u548c\u201c\u53f3\u8fb9\u754c\u201d<\/h3>\n\n\n\n<p>\u7a97\u53e3\u9898\u91cc\u8fd8\u6709\u4e00\u4e2a\u975e\u5e38\u5bb9\u6613\u88ab\u5ffd\u89c6\u7684\u672c\u8d28\uff1a\u786e\u8ba4\u53f7\u548c\u7a97\u53e3\u5b57\u6bb5\u5176\u5b9e\u662f\u5728\u4e00\u8d77\u5b9a\u4e49\u53d1\u9001\u7a7a\u95f4\u3002<\/p>\n\n\n\n<p>\u786e\u8ba4\u53f7\u51b3\u5b9a\u7684\u662f<strong>\u5de6\u8fb9\u754c<\/strong>\uff0c\u8868\u793a\u53d1\u9001\u65b9\u5df2\u7ecf\u786e\u8ba4\u5230\u4e86\u54ea\u91cc\u3002<br>\u7a97\u53e3\u5b57\u6bb5\u51b3\u5b9a\u7684\u662f<strong>\u53f3\u8fb9\u754c\u76f8\u5bf9\u5de6\u8fb9\u754c\u8fd8\u80fd\u5411\u524d\u5f00\u591a\u5bbd<\/strong>\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u5982\u679c\u63a5\u6536\u65b9\u53d1\u6765\uff1a<\/p>\n\n\n\n<p><code>ack = 5001, window = 3000<\/code><\/p>\n\n\n\n<p>\u8fd9\u8868\u793a\uff1a<\/p>\n\n\n\n<p>\u201c5000 \u53ca\u4ee5\u524d\u7684\u5b57\u8282\u6211\u90fd\u6309\u5e8f\u6536\u5230\u4e86\uff0c\u4f60\u63a5\u4e0b\u6765\u53ef\u4ee5\u4ece 5001 \u5f00\u59cb\u7ee7\u7eed\u53d1\uff0c\u5e76\u4e14\u6700\u591a\u8fd8\u53ef\u4ee5\u5411\u524d\u5360\u7528 3000B \u7684\u63a5\u6536\u7a97\u53e3\u7a7a\u95f4\u3002\u201d<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u505a\u9898\u65f6\u53ea\u4f1a\u628a\u7a97\u53e3\u5f53\u4f5c\u4e00\u4e2a\u5b64\u7acb\u6570\u5b57\u770b\uff0c\u6ca1\u628a\u5b83\u548c\u786e\u8ba4\u53f7\u7ed3\u5408\u8d77\u6765\u7406\u89e3\uff0c\u8fd9\u6837\u4e00\u9047\u5230\u56fe\u793a\u9898\u3001\u533a\u95f4\u9898\u3001\u53d1\u9001\u7a97\u53e3\u6ed1\u52a8\u9898\u5c31\u5bb9\u6613\u8499\u3002<\/p>\n\n\n\n<p>\u771f\u6b63\u7a33\u59a5\u7684\u7406\u89e3\u662f\uff1a<\/p>\n\n\n\n<p><strong>ack \u5b9a\u8d77\u70b9\uff0cwindow \u5b9a\u5bbd\u5ea6\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u3001\u628a MSS \u548c\u201c\u6574\u4e2a TCP \u62a5\u6587\u6bb5\u957f\u5ea6\u201d\u6df7\u6dc6<\/h3>\n\n\n\n<p>MSS \u4e5f\u662f\u4e00\u4e2a\u7279\u522b\u5bb9\u6613\u56e0\u4e3a\u540d\u5b57\u800c\u60f3\u5f53\u7136\u7406\u89e3\u9519\u7684\u6982\u5ff5\u3002<\/p>\n\n\n\n<p>MSS \u53eb\u6700\u5927\u62a5\u6587\u6bb5\u957f\u5ea6\uff0c\u4f46\u5b83\u6307\u7684\u5e76\u4e0d\u662f\u201c\u6574\u4e2a TCP \u62a5\u6587\u6bb5\u603b\u957f\u5ea6\u201d\uff0c\u800c\u662f\uff1a<\/p>\n\n\n\n<p><strong>TCP \u62a5\u6587\u6bb5\u4e2d\u6570\u636e\u90e8\u5206\u7684\u6700\u5927\u957f\u5ea6\u3002<\/strong><\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0cMSS \u4e0d\u5305\u62ec TCP \u9996\u90e8\uff0c\u4e5f\u4e0d\u5305\u62ec IP \u9996\u90e8\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u770b\u5230\u201c\u6700\u5927\u62a5\u6587\u6bb5\u957f\u5ea6\u201d\u5c31\u672c\u80fd\u89c9\u5f97\u662f\u6574\u4e2a\u6bb5\u4ece\u5934\u5230\u5c3e\u7684\u957f\u5ea6\uff0c\u8fd9\u6837\u4e00\u505a MTU \u76f8\u5173\u9898\u5c31\u4f1a\u51fa\u9519\u3002<\/p>\n\n\n\n<p>\u6700\u5e38\u89c1\u5173\u7cfb\u662f\uff1a<\/p>\n\n\n\n<p><code>MSS = MTU - IP\u9996\u90e8\u957f\u5ea6 - TCP\u9996\u90e8\u957f\u5ea6<\/code><\/p>\n\n\n\n<p>\u4f8b\u5982\u4ee5\u592a\u7f51 MTU=1500B\uff0cIPv4 \u9996\u90e8 20B\uff0cTCP \u9996\u90e8 20B\uff0c\u90a3\u4e48\uff1a<\/p>\n\n\n\n<p><code>MSS = 1500 - 20 - 20 = 1460B<\/code><\/p>\n\n\n\n<p>\u5982\u679c\u628a MSS \u8bef\u5f53\u6210\u6574\u4e2a IP \u6570\u636e\u62a5\u957f\u5ea6\uff0c\u6216\u8005\u8bef\u5f53\u6210\u542b\u9996\u90e8\u7684 TCP \u603b\u957f\u5ea6\uff0c\u7ed3\u679c\u90fd\u4f1a\u9519\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u8fd9\u4e2a\u70b9\u6700\u7a33\u7684\u8bb0\u6cd5\u5c31\u662f\uff1a<\/p>\n\n\n\n<p><strong>MSS \u53ea\u770b TCP \u8d1f\u8f7d\uff0c\u4e0d\u770b\u9996\u90e8\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e00\u3001\u628a MSS \u548c MTU \u770b\u6210\u4e00\u56de\u4e8b<\/h3>\n\n\n\n<p>MSS \u548c MTU \u7ecf\u5e38\u4e00\u8d77\u51fa\u73b0\uff0c\u56e0\u6b64\u5f88\u591a\u4eba\u4f1a\u987a\u624b\u628a\u5b83\u4eec\u6df7\u6210\u4e00\u4e2a\u6982\u5ff5\u3002<\/p>\n\n\n\n<p>\u4f46\u8fd9\u4e24\u4e2a\u91cf\u4e0d\u5728\u540c\u4e00\u5c42\u3002<\/p>\n\n\n\n<p>MTU \u662f\u6570\u636e\u94fe\u8def\u5c42\u6982\u5ff5\uff0c\u8868\u793a\u94fe\u8def\u5c42\u5e27\u4e2d\u53ef\u627f\u8f7d\u7684\u7f51\u7edc\u5c42\u6570\u636e\u7684\u6700\u5927\u957f\u5ea6\u3002<br>MSS \u662f\u4f20\u8f93\u5c42\u6982\u5ff5\uff0c\u8868\u793a TCP \u6570\u636e\u90e8\u5206\u6700\u5927\u957f\u5ea6\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5 MTU \u66f4\u9760\u4e0b\uff0cMSS \u66f4\u9760\u4e0a\u3002<br>MSS \u5f80\u5f80\u662f\u4e3a\u4e86\u9002\u914d MTU\uff0c\u907f\u514d IP \u5206\u7247\u800c\u786e\u5b9a\u7684\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u9898\u76ee\u540c\u65f6\u51fa\u73b0 MSS \u548c MTU\uff0c\u8981\u7acb\u523b\u53cd\u5e94\u8fc7\u6765\uff1a\u8fd9\u4e0d\u662f\u540c\u4e49\u66ff\u6362\uff0c\u800c\u662f\u4e0a\u4e0b\u5c42\u4e4b\u95f4\u7684\u7ea6\u675f\u5173\u7cfb\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e8c\u3001\u8bef\u4ee5\u4e3a\u4e09\u6b21\u63e1\u624b\u53ea\u662f\u201c\u6253\u62db\u547c\u201d\uff0c\u6ca1\u6293\u4f4f\u5176\u771f\u5b9e\u4f5c\u7528<\/h3>\n\n\n\n<p>\u5982\u679c\u53ea\u662f\u6b7b\u80cc\u201c\u4e09\u6b21\u63e1\u624b\u5efa\u7acb\u8fde\u63a5\u201d\uff0c\u4e00\u5230\u9009\u62e9\u9898\u95ee\u201c\u4e3a\u4ec0\u4e48\u8981\u4e09\u6b21\uff0c\u4e0d\u662f\u4e24\u6b21\u201d\uff0c\u5c31\u5bb9\u6613\u7b54\u5f97\u5f88\u865a\u3002<\/p>\n\n\n\n<p>\u4e09\u6b21\u63e1\u624b\u7684\u672c\u8d28\uff0c\u4e0d\u662f\u793c\u8c8c\u6027\u6253\u62db\u547c\uff0c\u800c\u662f\u53cc\u65b9\u8981\u786e\u8ba4\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6211\u80fd\u53d1<\/li>\n\n\n\n<li>\u6211\u80fd\u6536<\/li>\n\n\n\n<li>\u4f60\u80fd\u53d1<\/li>\n\n\n\n<li>\u4f60\u80fd\u6536<\/li>\n<\/ul>\n\n\n\n<p>\u6362\u53e5\u8bdd\u8bf4\uff0c\u53cc\u65b9\u90fd\u8981\u786e\u8ba4\u5f7c\u6b64\u6536\u53d1\u80fd\u529b\u6b63\u5e38\uff0c\u5e76\u5b8c\u6210\u521d\u59cb\u5e8f\u53f7\u540c\u6b65\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4e09\u6b21\u63e1\u624b\u7b2c\u4e8c\u6b65\u4e0d\u662f\u5355\u7eaf\u56de\u590d\u4e00\u53e5\u201c\u597d\u201d\uff0c\u800c\u662f\u670d\u52a1\u5668\u4e00\u8fb9\u786e\u8ba4\u5ba2\u6237\u7aef\u7684 SYN\uff0c\u4e00\u8fb9\u628a\u81ea\u5df1\u7684 SYN \u53d1\u51fa\u53bb\uff1b\u7b2c\u4e09\u6b21\u63e1\u624b\u5219\u662f\u5ba2\u6237\u7aef\u786e\u8ba4\u670d\u52a1\u5668\u7684 SYN \u5df2\u7ecf\u6536\u5230\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u8fd9\u4e2a\u903b\u8f91\u6ca1\u641e\u6e05\uff0c\u4e00\u5230\u9898\u76ee\u53d8\u5f62\u6210\u201c\u4e3a\u4ec0\u4e48\u4e24\u6b21\u4e0d\u591f\u201d\u201c\u4e3a\u4ec0\u4e48\u7b2c\u4e09\u6b21\u5fc5\u8981\u201d\u201c\u5931\u6548\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\u6bb5\u4e3a\u4f55\u4f1a\u51fa\u95ee\u9898\u201d\u65f6\uff0c\u5c31\u53ea\u80fd\u9760\u6b7b\u8bb0\u786c\u80cc\uff0c\u5f88\u5bb9\u6613\u7b54\u4e71\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e09\u3001\u8bef\u4ee5\u4e3a\u56db\u6b21\u6325\u624b\u662f\u201c\u89c4\u5b9a\u52a8\u4f5c\u201d\uff0c\u6ca1\u7406\u89e3\u4e3a\u4ec0\u4e48\u901a\u5e38\u9700\u8981\u56db\u6b21<\/h3>\n\n\n\n<p>\u540c\u6837\u5730\uff0c\u56db\u6b21\u6325\u624b\u5982\u679c\u53ea\u80cc\u6d41\u7a0b\uff0c\u4e0d\u7406\u89e3\u539f\u56e0\uff0c\u4e5f\u5f88\u5bb9\u6613\u5728\u9898\u76ee\u53d8\u5f62\u65f6\u51fa\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u56db\u6b21\u6325\u624b\u4e4b\u6240\u4ee5\u901a\u5e38\u662f\u56db\u6b21\uff0c\u4e0d\u662f\u56e0\u4e3a TCP \u4eba\u4e3a\u89c4\u5b9a\u8981\u56db\u6b21\uff0c\u800c\u662f\u56e0\u4e3a TCP \u662f\u5168\u53cc\u5de5\uff0c\u4e24\u4e2a\u65b9\u5411\u7684\u5173\u95ed\u8981\u5206\u5f00\u8fdb\u884c\u3002<\/p>\n\n\n\n<p>A \u53d1 FIN\uff0c\u53ea\u8868\u793a A \u8fd9\u8fb9\u6ca1\u6709\u6570\u636e\u8981\u53d1\u4e86\uff0c\u5373 A \u2192 B \u8fd9\u4e2a\u65b9\u5411\u51c6\u5907\u5173\u95ed\u3002<br>\u4f46\u8fd9\u5e76\u4e0d\u610f\u5473\u7740 B \u2192 A \u65b9\u5411\u4e5f\u7acb\u523b\u6ca1\u6570\u636e\u4e86\uff0c\u6240\u4ee5 B \u5148\u56de\u4e00\u4e2a ACK\uff0c\u7b49\u81ea\u5df1\u6570\u636e\u53d1\u9001\u5b8c\u6bd5\u540e\uff0c\u518d\u53d1 FIN\u3002<\/p>\n\n\n\n<p>\u8fd9\u624d\u5f62\u6210\u4e86\u201cFIN \u2192 ACK \u2192 FIN \u2192 ACK\u201d\u7684\u56db\u6b65\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u6ca1\u6293\u4f4f\u201c\u4e24\u4e2a\u65b9\u5411\u72ec\u7acb\u5173\u95ed\u201d\u8fd9\u4e2a\u672c\u8d28\uff0c\u5c31\u4f1a\u5bf9\u5f88\u591a\u53d8\u5f62\u9898\u611f\u5230\u56f0\u60d1\uff0c\u6bd4\u5982\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e3a\u4ec0\u4e48\u4e0d\u80fd\u603b\u662f\u4e09\u6b21\u6325\u624b<\/li>\n\n\n\n<li>\u4e3a\u4ec0\u4e48\u7b2c\u4e8c\u6b21\u548c\u7b2c\u4e09\u6b21\u6709\u65f6\u80fd\u5408\u5e76<\/li>\n\n\n\n<li>\u4e3a\u4ec0\u4e48\u6536\u5230 FIN \u540e\u4e0d\u4e00\u5b9a\u9a6c\u4e0a\u4e5f\u53d1 FIN<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u4e9b\u95ee\u9898\u7684\u7b54\u6848\uff0c\u672c\u8d28\u90fd\u6765\u81ea\u201c\u5168\u53cc\u5de5\u3001\u53cc\u5411\u72ec\u7acb\u5173\u95ed\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u56db\u3001\u770b\u5230\u56db\u6b21\u6325\u624b\u5c31\u5fd8\u4e86 TIME-WAIT \u7684\u610f\u4e49<\/h3>\n\n\n\n<p>TIME-WAIT \u662f TCP \u91cc\u53e6\u4e00\u4e2a\u9ad8\u9891\u4f46\u5f88\u5bb9\u6613\u80cc\u5f97\u7a7a\u6d1e\u7684\u70b9\u3002<\/p>\n\n\n\n<p>\u5f88\u591a\u4eba\u53ea\u8bb0\u5f97\u201c\u4e3b\u52a8\u5173\u95ed\u65b9\u6700\u540e\u8981\u8fdb\u5165 TIME-WAIT\uff0c\u7b49\u5f85 2MSL\u201d\uff0c\u4f46\u4e0d\u77e5\u9053\u4e3a\u4ec0\u4e48\uff0c\u4e8e\u662f\u4e00\u5230\u9009\u62e9\u9898\u5c31\u5bb9\u6613\u5728\u8868\u8ff0\u4e0a\u88ab\u5e72\u6270\u3002<\/p>\n\n\n\n<p>TIME-WAIT \u7684\u4e3b\u8981\u4f5c\u7528\u901a\u5e38\u53ef\u4ee5\u5f52\u7eb3\u6210\u4e24\u4e2a\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u4fdd\u8bc1\u6700\u540e\u4e00\u4e2a ACK \u80fd\u5230\u8fbe\u3002<br>\u5982\u679c\u4e3b\u52a8\u5173\u95ed\u65b9\u53d1\u51fa\u7684\u6700\u540e ACK \u4e22\u5931\uff0c\u90a3\u4e48\u88ab\u52a8\u5173\u95ed\u65b9\u4f1a\u91cd\u4f20 FIN\u3002\u4e3b\u52a8\u5173\u95ed\u65b9\u5728 TIME-WAIT \u72b6\u6001\u4e0b\u8fd8\u80fd\u91cd\u53d1 ACK\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\uff0c\u9632\u6b62\u65e7\u8fde\u63a5\u4e2d\u7684\u5ef6\u8fdf\u62a5\u6587\u6bb5\u5f71\u54cd\u540e\u7eed\u65b0\u8fde\u63a5\u3002<br>\u7b49\u5f85 2MSL\uff0c\u53ef\u4ee5\u8ba9\u7f51\u7edc\u4e2d\u8be5\u8fde\u63a5\u6b8b\u7559\u7684\u65e7\u62a5\u6587\u6bb5\u57fa\u672c\u5931\u6548\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u8fd9\u4e24\u4e2a\u4f5c\u7528\u53ea\u8bb0\u4f4f\u4e00\u53e5\u6a21\u7cca\u7684\u201c\u907f\u514d\u51fa\u9519\u201d\uff0c\u505a\u9898\u65f6\u5c31\u4e0d\u7262\u3002\u6700\u597d\u76f4\u63a5\u8bb0\u6210\uff1a<\/p>\n\n\n\n<p><strong>TIME-WAIT = \u9632\u6700\u540e ACK \u4e22\u5931 + \u9632\u65e7\u62a5\u6587\u5e72\u6270\u65b0\u8fde\u63a5\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e94\u3001\u628a\u201c\u53ef\u9760\u4f20\u8f93\u201d\u7b80\u5355\u7406\u89e3\u6210\u201c\u6c38\u8fdc\u4e0d\u4f1a\u4e22\u201d<\/h3>\n\n\n\n<p>TCP \u53ef\u9760\uff0c\u4e0d\u7b49\u4e8e\u7269\u7406\u4e0a\u6c38\u8fdc\u4e0d\u4e22\u5305\u3002<br>TCP \u53ef\u9760\u7684\u771f\u6b63\u542b\u4e49\u662f\uff1a\u5373\u4f7f\u7f51\u7edc\u4e2d\u53ef\u80fd\u4e22\u5931\u3001\u5931\u5e8f\u3001\u91cd\u590d\uff0cTCP \u4e5f\u901a\u8fc7\u786e\u8ba4\u3001\u91cd\u4f20\u3001\u6392\u5e8f\u3001\u6821\u9a8c\u7b49\u673a\u5236\uff0c\u5c3d\u91cf\u4fdd\u8bc1\u5e94\u7528\u5c42\u6700\u7ec8\u62ff\u5230\u6b63\u786e\u3001\u6309\u5e8f\u3001\u4e0d\u91cd\u590d\u7684\u6570\u636e\u6d41\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u70b9\u5728\u6982\u5ff5\u5224\u65ad\u9898\u91cc\u5f88\u5bb9\u6613\u51fa\u201c\u8bed\u8a00\u9677\u9631\u201d\u3002<\/p>\n\n\n\n<p>\u6bd4\u5982\u9898\u76ee\u8bf4\uff1a<\/p>\n\n\n\n<p>\u201cTCP \u53ef\u9760\u4f20\u8f93\u662f\u6307\u5728\u4f20\u8f93\u8fc7\u7a0b\u4e2d\u4e0d\u4f1a\u53d1\u751f\u4e22\u5305\u3002\u201d<\/p>\n\n\n\n<p>\u8fd9\u79cd\u8bf4\u6cd5\u5c31\u662f\u9519\u7684\u3002<br>\u7f51\u7edc\u4e2d\u5f53\u7136\u53ef\u80fd\u4e22\u5305\uff0cTCP \u7684\u53ef\u9760\u6027\u6070\u6070\u662f\u5efa\u7acb\u5728\u201c\u53ef\u80fd\u4e22\u3001\u4f46\u80fd\u8865\u6551\u201d\u7684\u673a\u5236\u4e0a\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4ee5\u540e\u770b\u5230\u201c\u53ef\u9760\u201d\u4e8c\u5b57\uff0c\u4e0d\u8981\u628a\u5b83\u7406\u89e3\u6210\u201c\u7edd\u4e0d\u51fa\u9519\u201d\uff0c\u800c\u8981\u7406\u89e3\u6210\u201c\u901a\u8fc7\u534f\u8bae\u673a\u5236\u4fdd\u8bc1\u6b63\u786e\u4ea4\u4ed8\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u516d\u3001\u628a TCP \u8bef\u5f53\u6210\u6570\u636e\u94fe\u8def\u5c42 GBN \u7684\u7b80\u5355\u7ffb\u7248<\/h3>\n\n\n\n<p>\u8fd9\u4e2a\u5751\u901a\u5e38\u51fa\u73b0\u5728\u5b66\u5b8c\u6570\u636e\u94fe\u8def\u5c42\u6ed1\u52a8\u7a97\u53e3\u534f\u8bae\u4e4b\u540e\u3002<\/p>\n\n\n\n<p>TCP \u786e\u5b9e\u548c GBN\u3001\u6ed1\u52a8\u7a97\u53e3\u6709\u76f8\u4f3c\u6027\uff0c\u6bd4\u5982\u90fd\u6709\u5e8f\u53f7\u3001\u786e\u8ba4\u3001\u7a97\u53e3\u3001\u8d85\u65f6\u91cd\u4f20\u3001\u6d41\u6c34\u7ebf\u53d1\u9001\uff0c\u6240\u4ee5\u521d\u5b66\u65f6\u4f1a\u89c9\u5f97\u201cTCP \u4e0d\u5c31\u662f\u66f4\u590d\u6742\u4e00\u70b9\u7684 GBN \u5417\u201d\u3002<\/p>\n\n\n\n<p>\u8fd9\u79cd\u611f\u89c9\u4e0d\u7b97\u5b8c\u5168\u9519\uff0c\u4f46\u5982\u679c\u76f4\u63a5\u628a\u5b83\u4eec\u7b49\u540c\u8d77\u6765\uff0c\u5c31\u4f1a\u51fa\u95ee\u9898\u3002<\/p>\n\n\n\n<p>TCP \u548c GBN \u81f3\u5c11\u6709\u51e0\u4e2a\u6839\u672c\u5dee\u5f02\u3002<\/p>\n\n\n\n<p>\u9996\u5148\uff0c\u5c42\u6b21\u4e0d\u540c\u3002<br>GBN \u662f\u6570\u636e\u94fe\u8def\u5c42\u534f\u8bae\u601d\u60f3\uff0cTCP \u662f\u4f20\u8f93\u5c42\u534f\u8bae\u3002<\/p>\n\n\n\n<p>\u5176\u6b21\uff0c\u7f16\u53f7\u5355\u4f4d\u4e0d\u540c\u3002<br>GBN \u901a\u5e38\u6309\u5e27\u7f16\u53f7\uff0cTCP \u6309\u5b57\u8282\u7f16\u53f7\u3002<\/p>\n\n\n\n<p>\u518d\u6b21\uff0cTCP \u9664\u4e86\u53ef\u9760\u4f20\u8f93\uff0c\u8fd8\u8981\u5904\u7406\u6d41\u91cf\u63a7\u5236\u548c\u62e5\u585e\u63a7\u5236\u3002<br>GBN \u4e3b\u8981\u4e0d\u662f\u4e3a\u4e86\u89e3\u51b3\u7f51\u7edc\u62e5\u585e\u95ee\u9898\u8bbe\u8ba1\u7684\u3002<\/p>\n\n\n\n<p>\u6700\u540e\uff0cTCP \u7684\u786e\u8ba4\u4e0e\u91cd\u4f20\u673a\u5236\u66f4\u590d\u6742\uff0c\u5b9e\u9645\u5b9e\u73b0\u4e2d\u8fd8\u53ef\u80fd\u6709\u5ef6\u8fdf\u786e\u8ba4\u3001\u91cd\u590d ACK\u3001\u5feb\u91cd\u4f20\u3001SACK \u7b49\u673a\u5236\uff0c\u4e0d\u80fd\u7b80\u5355\u5957\u6210\u201c\u4e22\u4e00\u4e2a\u5c31\u5168\u56de\u9000\u201d\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u66f4\u7a33\u7684\u8868\u8ff0\u5e94\u8be5\u662f\uff1a<\/p>\n\n\n\n<p><strong>TCP \u5728\u786e\u8ba4\u548c\u7a97\u53e3\u601d\u60f3\u4e0a\u4e0e\u6ed1\u52a8\u7a97\u53e3\u534f\u8bae\u76f8\u4f3c\uff0c\u4f46\u5b83\u4e0d\u662f\u7b80\u5355\u7b49\u540c\u4e8e GBN\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e03\u3001\u628a\u201c\u7d2f\u8ba1\u786e\u8ba4\u201d\u7406\u89e3\u6210\u201c\u53ea\u80fd\u786e\u8ba4\u4e00\u4e2a\u62a5\u6587\u6bb5\u201d<\/h3>\n\n\n\n<p>TCP \u7684\u7d2f\u8ba1\u786e\u8ba4\u673a\u5236\u4e5f\u662f\u4e00\u4e2a\u5f88\u5bb9\u6613\u88ab\u8868\u9762\u5316\u7406\u89e3\u7684\u70b9\u3002<\/p>\n\n\n\n<p>\u6240\u8c13\u7d2f\u8ba1\u786e\u8ba4\uff0c\u4e0d\u662f\u201c\u6bcf\u6b21\u53ea\u786e\u8ba4\u5f53\u524d\u8fd9\u4e2a\u62a5\u6587\u6bb5\u201d\uff0c\u800c\u662f\uff1a<\/p>\n\n\n\n<p><strong>\u786e\u8ba4\u53f7\u4e00\u65e6\u63a8\u8fdb\u5230\u67d0\u4e2a\u4f4d\u7f6e\uff0c\u5c31\u8868\u793a\u8fd9\u4e2a\u4f4d\u7f6e\u4e4b\u524d\u6309\u5e8f\u5230\u8fbe\u7684\u6570\u636e\u90fd\u5df2\u7ecf\u6536\u5230\u4e86\u3002<\/strong><\/p>\n\n\n\n<p>\u4f8b\u5982 ack=5001\uff0c\u5e76\u4e0d\u662f\u53ea\u786e\u8ba4\u4e00\u4e2a\u201c5000 \u53f7\u5305\u201d\uff0c\u800c\u662f\u786e\u8ba4\u5230 5000 \u4e3a\u6b62\u7684\u6240\u6709\u6309\u5e8f\u5b57\u8282\u90fd\u5df2\u6536\u5230\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u70b9\u5982\u679c\u6ca1\u7406\u89e3\uff0c\u4e00\u5230\u5224\u65ad\u9898\u91cc\u51fa\u73b0\u201cTCP \u6bcf\u6536\u5230\u4e00\u4e2a\u62a5\u6587\u6bb5\u53ea\u786e\u8ba4\u8be5\u62a5\u6587\u6bb5\u201d\u8fd9\u79cd\u8bf4\u6cd5\uff0c\u5c31\u5f88\u5bb9\u6613\u8bef\u5224\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u516b\u3001\u5e8f\u53f7\u7ed5\u56de\u9898\u91cc\u5fd8\u8bb0\u5355\u4f4d\u6362\u7b97<\/h3>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u5c5e\u4e8e\u8ba1\u7b97\u5e76\u4e0d\u96be\uff0c\u4f46\u5f88\u5bb9\u6613\u56e0\u4e3a\u5355\u4f4d\u800c\u7ffb\u8f66\u3002<\/p>\n\n\n\n<p>TCP \u5e8f\u53f7 32 \u4f4d\uff0c\u5e8f\u53f7\u7a7a\u95f4\u662f\u4e00\u5708 <code>2^32<\/code>\u3002<br>\u5173\u952e\u662f\uff1a\u8fd9\u4e2a <code>2^32<\/code> \u7684\u5355\u4f4d\u662f<strong>\u5b57\u8282<\/strong>\uff0c\u4e0d\u662f bit\uff0c\u4e5f\u4e0d\u662f\u62a5\u6587\u6bb5\u4e2a\u6570\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u9898\u76ee\u518d\u7ed9\u94fe\u8def\u901f\u7387\uff0c\u6bd4\u5982 10Gb\/s\u300140Gb\/s\uff0c\u90a3\u4e48\u5fc5\u987b\u5148\u628a\u901f\u7387\u4ece bit\/s \u6362\u6210 B\/s\uff0c\u518d\u53bb\u8ba1\u7b97\uff1a<\/p>\n\n\n\n<p><code>\u65f6\u95f4 = 2^32 B \u00f7 \u53d1\u9001\u901f\u7387(B\/s)<\/code><\/p>\n\n\n\n<p>\u6700\u5bb9\u6613\u9519\u7684\u5730\u65b9\u901a\u5e38\u6709\u4e24\u4e2a\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u5fd8\u8bb0 TCP \u6309\u5b57\u8282\u7f16\u53f7\uff0c\u628a <code>2^32<\/code> \u8bef\u5f53\u6210 bit\u3002<br>\u7b2c\u4e8c\uff0c\u5fd8\u8bb0 <code>1B = 8bit<\/code>\uff0c\u76f4\u63a5\u62ff bit\/s \u53bb\u9664 byte \u6570\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4ee5\u540e\u53ea\u8981\u770b\u5230\u201cTCP \u5e8f\u53f7\u7ed5\u56de\u201d\u51e0\u4e2a\u5b57\uff0c\u5148\u5728\u8111\u4e2d\u81ea\u52a8\u8865\u4e00\u53e5\uff1a<\/p>\n\n\n\n<p><strong>\u5148\u7edf\u4e00\u5355\u4f4d\uff0c\u5e8f\u53f7\u7a7a\u95f4\u6309\u5b57\u8282\u7b97\u3002<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5341\u4e5d\u3001\u628a\u201c\u5efa\u7acb\u8fde\u63a5\u9700\u8981\u4e09\u6b21\u201d\u6b7b\u8bb0\u6210\u7edd\u5bf9\u683c\u5f0f\uff0c\u4e0d\u4f1a\u5904\u7406\u53d8\u5f62\u9898<\/h3>\n\n\n\n<p>\u5f88\u591a\u5b66\u751f\u80cc\u719f\u7684\u662f\u4e00\u4e2a\u6807\u51c6\u56fe\uff1a<\/p>\n\n\n\n<p><code>SYN \u2192 SYN+ACK \u2192 ACK<\/code><\/p>\n\n\n\n<p>\u4f46\u9898\u76ee\u4e00\u65e6\u53d8\u5f62\uff0c\u6bd4\u5982\u95ee\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7b2c\u4e09\u6b21\u63e1\u624b\u80fd\u4e0d\u80fd\u643a\u5e26\u6570\u636e<\/li>\n\n\n\n<li>\u7b2c\u4e8c\u6b21\u63e1\u624b\u4e3a\u4ec0\u4e48\u65e2\u6709 SYN \u53c8\u6709 ACK<\/li>\n\n\n\n<li>\u67d0\u4e2a\u62a5\u6587\u6bb5\u4e22\u5931\u4f1a\u53d1\u751f\u4ec0\u4e48<\/li>\n<\/ul>\n\n\n\n<p>\u5c31\u5bb9\u6613\u4e0d\u4f1a\u4e86\u3002<\/p>\n\n\n\n<p>\u672c\u8d28\u4e0a\uff0c\u4e09\u6b21\u63e1\u624b\u4e0d\u662f\u80cc\u201c\u54ea\u4e09\u4e2a\u5305\u201d\uff0c\u800c\u662f\u80cc\u201c\u53cc\u65b9\u5404\u81ea\u8981\u5b8c\u6210\u4ec0\u4e48\u72b6\u6001\u786e\u8ba4\u201d\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u4e00\u65e6\u7406\u89e3\u4e3a\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5ba2\u6237\u7aef\u53d1\u8d77\u540c\u6b65\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u53f7<\/li>\n\n\n\n<li>\u670d\u52a1\u5668\u786e\u8ba4\u5ba2\u6237\u7aef\u5e76\u540c\u6b65\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u53f7<\/li>\n\n\n\n<li>\u5ba2\u6237\u7aef\u786e\u8ba4\u670d\u52a1\u5668\u7684\u521d\u59cb\u5e8f\u53f7<\/li>\n<\/ul>\n\n\n\n<p>\u5f88\u591a\u53d8\u5f62\u9898\u5c31\u987a\u4e86\u3002<\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u63e1\u624b\u9898\u4e0d\u8981\u53ea\u8bb0\u201c\u56fe\u201d\uff0c\u66f4\u8981\u8bb0\u201c\u6bcf\u4e00\u6b65\u5404\u81ea\u5728\u786e\u8ba4\u4ec0\u4e48\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e8c\u5341\u3001\u628a\u9898\u76ee\u91cc\u7684\u201c\u62a5\u6587\u6bb5\u201d\u201c\u786e\u8ba4\u53f7\u201d\u201c\u7a97\u53e3\u201d\u5272\u88c2\u5f00\u770b<\/h3>\n\n\n\n<p>\u8fd9\u662f\u5f88\u591a\u7efc\u5408\u9898\u505a\u4e0d\u51fa\u6765\u7684\u6839\u672c\u539f\u56e0\u3002<\/p>\n\n\n\n<p>TCP \u5927\u9898\u5f80\u5f80\u4e0d\u662f\u5355\u72ec\u8003\u67d0\u4e2a\u70b9\uff0c\u800c\u662f\u628a\u8fd9\u4e9b\u91cf\u653e\u5728\u4e00\u8d77\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u67d0\u62a5\u6587\u6bb5\u7684 seq<\/li>\n\n\n\n<li>\u67d0\u62a5\u6587\u6bb5\u7684\u6570\u636e\u957f\u5ea6<\/li>\n\n\n\n<li>\u6536\u5230\u540e\u7684 ack<\/li>\n\n\n\n<li>\u63a5\u6536\u7a97\u53e3\u5927\u5c0f<\/li>\n\n\n\n<li>\u8fd8\u80fd\u7ee7\u7eed\u53d1\u9001\u591a\u5c11<\/li>\n\n\n\n<li>\u4e0b\u4e00\u6b21\u53d1\u9001\u7684 seq \u5e94\u8be5\u662f\u591a\u5c11<\/li>\n<\/ul>\n\n\n\n<p>\u5982\u679c\u590d\u4e60\u65f6\u628a\u8fd9\u4e9b\u5185\u5bb9\u5b64\u7acb\u80cc\u8bf5\uff0c\u505a\u9898\u65f6\u5c31\u4f1a\u89c9\u5f97\u4fe1\u606f\u592a\u591a\u3001\u592a\u4e71\u3002<\/p>\n\n\n\n<p>\u5176\u5b9e\u8fd9\u4e9b\u4fe1\u606f\u4e4b\u95f4\u7684\u5173\u7cfb\u975e\u5e38\u56fa\u5b9a\uff1a<\/p>\n\n\n\n<p><code>seq<\/code> \u51b3\u5b9a\u672c\u6bb5\u4ece\u54ea\u5f00\u59cb\u3002<br><code>\u6570\u636e\u957f\u5ea6<\/code> \u51b3\u5b9a\u672c\u6bb5\u53d1\u5230\u54ea\u3002<br><code>ack<\/code> \u51b3\u5b9a\u5bf9\u65b9\u786e\u8ba4\u5230\u4e86\u54ea\u3002<br><code>window<\/code> \u51b3\u5b9a\u8fd8\u80fd\u5411\u524d\u5f00\u591a\u5bbd\u3002<br>\u4e8e\u662f\u5c31\u80fd\u5224\u65ad\u4e0b\u4e00\u6bb5\u4ece\u54ea\u53d1\u3001\u8fd8\u80fd\u53d1\u591a\u5c11\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5 TCP \u7efc\u5408\u9898\u771f\u6b63\u7684\u6838\u5fc3\u4e0d\u662f\u201c\u8bb0\u4f4f\u5f88\u591a\u77e5\u8bc6\u70b9\u201d\uff0c\u800c\u662f\u628a\u51e0\u4e2a\u91cf\u7684\u5173\u7cfb\u8fde\u8d77\u6765\u770b\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u6700\u540e\u538b\u7f29\u6210\u4e00\u7248\u201c\u9ad8\u9891\u5751\u70b9\u901f\u8bb0\u6e05\u5355\u201d<\/h2>\n\n\n\n<p>\u5982\u679c\u8003\u524d\u53ea\u60f3\u5feb\u901f\u626b\u4e00\u904d\uff0c\u4e0b\u9762\u8fd9\u4e00\u7248\u6700\u9002\u5408\u76f4\u63a5\u8fc7\u8111\u5b50\u3002<\/p>\n\n\n\n<p>TCP \u9762\u5411\u5b57\u8282\u6d41\uff0c\u4e0d\u4fdd\u7559\u6d88\u606f\u8fb9\u754c\uff1bUDP \u9762\u5411\u62a5\u6587\uff0c\u4fdd\u7559\u6d88\u606f\u8fb9\u754c\u3002<br>TCP \u7684 seq \u6309\u5b57\u8282\u7f16\u53f7\uff0c\u4e0d\u6309\u62a5\u6587\u6bb5\u7f16\u53f7\u3002<br>TCP \u7684 ack \u8868\u793a\u201c\u671f\u671b\u6536\u5230\u7684\u4e0b\u4e00\u4e2a\u5b57\u8282\u7f16\u53f7\u201d\u3002<br>SYN \u5360 1 \u4e2a\u5e8f\u53f7\uff0cFIN \u5360 1 \u4e2a\u5e8f\u53f7\uff0c\u7eaf ACK \u4e0d\u5360\u5e8f\u53f7\u3002<br>TCP \u9996\u90e8\u4e2d\u7684\u7a97\u53e3\u5b57\u6bb5\u662f\u63a5\u6536\u65b9\u901a\u544a\u7a97\u53e3\uff0c\u4e0d\u662f\u53d1\u9001\u65b9\u81ea\u62a5\u53d1\u9001\u80fd\u529b\u3002<br>\u53d1\u9001\u7a97\u53e3\u4e0a\u9650\u53d6 <code>min(rwnd, cwnd)<\/code>\u3002<br>\u5f53\u524d\u8fd8\u80fd\u53d1\u9001\u7684\u6570\u636e\u91cf\uff0c\u8981\u518d\u51cf\u53bb\u5df2\u53d1\u9001\u672a\u786e\u8ba4\u90e8\u5206\u3002<br>ack \u51b3\u5b9a\u5de6\u8fb9\u754c\uff0cwindow \u51b3\u5b9a\u5bbd\u5ea6\u3002<br>MSS \u53ea\u6307 TCP \u6570\u636e\u90e8\u5206\u6700\u5927\u957f\u5ea6\uff0c\u4e0d\u542b TCP\/IP \u9996\u90e8\u3002<br>MSS \u548c MTU \u4e0d\u662f\u4e00\u56de\u4e8b\uff0c\u524d\u8005\u662f\u4f20\u8f93\u5c42\u6982\u5ff5\uff0c\u540e\u8005\u662f\u94fe\u8def\u5c42\u6982\u5ff5\u3002<br>\u4e09\u6b21\u63e1\u624b\u7684\u672c\u8d28\u662f\u53cc\u65b9\u786e\u8ba4\u5f7c\u6b64\u6536\u53d1\u80fd\u529b\u5e76\u540c\u6b65\u521d\u59cb\u5e8f\u53f7\u3002<br>\u56db\u6b21\u6325\u624b\u901a\u5e38\u662f\u56e0\u4e3a TCP \u5168\u53cc\u5de5\uff0c\u4e24\u4e2a\u65b9\u5411\u8981\u5206\u522b\u5173\u95ed\u3002<br>TIME-WAIT \u7684\u4f5c\u7528\u662f\u4fdd\u8bc1\u6700\u540e ACK \u53ef\u91cd\u53d1\uff0c\u4ee5\u53ca\u9632\u65e7\u62a5\u6587\u5e72\u6270\u65b0\u8fde\u63a5\u3002<br>TCP \u53ef\u9760\u4e0d\u7b49\u4e8e\u6c38\u4e0d\u4e22\u5305\uff0c\u800c\u662f\u901a\u8fc7\u534f\u8bae\u673a\u5236\u4fdd\u8bc1\u6700\u7ec8\u6b63\u786e\u4ea4\u4ed8\u3002<br>TCP \u4e0e\u6ed1\u52a8\u7a97\u53e3\u534f\u8bae\u76f8\u4f3c\uff0c\u4f46\u4e0d\u80fd\u7b80\u5355\u7b49\u540c\u4e8e GBN\u3002<br>\u5e8f\u53f7\u7ed5\u56de\u9898\u4e00\u5b9a\u5148\u7edf\u4e00\u5355\u4f4d\uff0c\u6309\u5b57\u8282\u7f16\u53f7\u3001\u6309\u5b57\u8282\u901f\u7387\u8ba1\u7b97\u3002<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001\u5148\u628a\u6700\u5bb9\u6613\u6df7\u7684\u5730\u65b9\u634b\u987a\uff1aTCP\u201c\u62a5\u6587\u6bb5\u201d\u548c UDP\u201c\u7528\u6237\u6570\u636e\u62a5\u201d\u5230\u5e95\u6709\u4ec0\u4e48\u533a\u522b \u8fd9\u90e8\u5206\u5728\u8003\u7814\u91cc\u5f88\u5bb9\u6613\u88ab\u4e00\u53e5 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[54],"tags":[],"class_list":["post-2075","post","type-post","status-publish","format-standard","hentry","category-text"],"_links":{"self":[{"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/posts\/2075","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/comments?post=2075"}],"version-history":[{"count":2,"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/posts\/2075\/revisions"}],"predecessor-version":[{"id":2077,"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/posts\/2075\/revisions\/2077"}],"wp:attachment":[{"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/media?parent=2075"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/categories?post=2075"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.preluna.xyz\/index.php\/wp-json\/wp\/v2\/tags?post=2075"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}