TCP 全双工数据保持关闭：功能与实现

TCP\u7684\u5168\u53cc\u5de5\u6570\u636e\u4fdd\u6301\u5173\u95ed\u662f\u4e00\u4e2a\u5728\u7c7b\u4f3c\u7684\u753b\u50cf\u7684 ISO\u4f20\u8f93\u534f\u8bae TP4\u4e2d\u4e0d\u542b\u6709\u7684\u7279\u6027\u3002\u4e00\u4e9b\u7cfb\u7edf\u6ca1\u6709\u5b9e\u73b0\u534a\u5173\u95ed\u7684\u8fde\u63a5\uff0c\u53ef\u80fd\u662f\u56e0\u4e3a\u5b83\u4eec\u4e0d\u7b26\u5408\u5176\u7279\u5b9a\u64cd\u4f5c\u7cfb\u7edf\u7684 I/O\u6a21\u5f0f\u3002\u5728\u8fd9\u4e9b\u7cfb\u7edf\u4e0a\uff0c\u4e00\u6b21\u5e94\u7528\u7a0b\u5e8f\u8c03\u7528\u4e86 CLOSE\uff0c\u5c31\u4e0d\u80fd\u518d\u4ece\u8fde\u63a5\u4e2d\u8bfb\u53d6\u8f93\u5165\u6570\u636e\uff1b\u8fd9\u88ab\u53eb\u505a\u201c\u534a\u53cc\u5de5\u201d\u7684 TCP\u5173\u95ed\u5e8f\u5217\u3002TCP\u7684\u4f18\u96c5\u5173\u95ed\u7b97\u6cd5\u8981\u6c42\u8fde\u63a5\u72b6\u6001\u5728\u8fde\u63a5\u7684\u81f3\u5c11\u4e00\u7aef\u4fdd\u6301\u5b9a\u4e49\uff0c\u8d85\u65f6\u65f6\u95f4\u4e3a 2\u500d MSL\uff0c\u5373 4\u5206\u949f\u3002\u5728\u6b64\u65f6\u95f4\u5185\uff0c\u5b9a\u4e49\u8fde\u63a5\u7684\uff08\u8fdc\u7aef\u5957\u63a5\u5b50\uff0c\u672c\u5730\u5957\u63a5\u5b50\uff09\u5bf9\u662f\u752f\u63a5\u7684\uff0c\u4e0d\u80fd\u91cd\u65b0\u4f7f\u7528\u3002\u4e3a\u4e86\u7f29\u77ed\u7ed9\u5b9a\u7aef\u53e3\u5bf9\u88ab\u5360\u7528\u7684\u65f6\u95f4\uff0c\u4e00\u4e9b TCP\u5141\u8bb8\u5728 TIME-WAIT\u72b6\u6001\u4e0b\u63a5\u53d7\u65b0\u7684 SYN\u3002