?????????????????????????????
?????????????????????????????????????????????????????????????????????????????????????????????????????????Щ?????￡????????????????潻?????衣
???????????NAT??????
????IPV4?????????????????????NAT·???豸????????????豸?????????????????TCP?????????NAT?豸????????????????????????????????????IP:PORT??????IP:PORT??????????????????????????????????????г??????????????????????????
???????NAT?豸???????????????????????????????????NAT?豸???????????????????????????????????????й???????????????????????????????5????????????????в?????????????????????????
??????????????IP????
???????????????2G/3G/4G??WIFI????л???????IP????????????????????????????е?????????-??????????????????????????????·?????????????????????
???????Multipath TCP??????豸???????????? 2G/3G/4G ?? WiFi ????Mutlpath?????????????????????????????????????y????????繲???????￡?????????ж????????????????ж?????豸???????????????????????????
???????????????????????????Multipath TCP???????????????????????
??????????
?????????IOS 7????????汾???
????Linux kernel 3.10????????????????????????????????????????????δ?
?????????????A closer look at the scientific literature on Multipath TCP
???????????TCP????????
??????·???????????????????????г?????????????????????????????????????ó?????????????????????????????????????????
??????????????????????????????????????????????????????????????°棬??????3.6???ɡ?
?????????????Bufferbloat
???????????TCP????????
????IP??TCPЭ?????????????check sum????У???????16λ?????????????????????????ο? TCPУ?????????????????????????????????????????16λ?????????????????????ī???
??????????CRC32У?????????????OK?????????????????????·????????￡??п?????????????????????????????

?????????Client??Server???????TCP segment?????segment???????????IP packet??????????ethernet frame???????·????????????a????Router???ethernet frame (b)????????????????(c)????Server???d??????ó???Ethernet CRC????a??b?????c??d?????TCP header check sum???????????????payload????????????????????Router????NAT?????NAT???????c???滻???????????????a??d??payload??????tcp header checksumУ?顣
????·?????????????????/????????????IP????????bit/??bit??????????????????????????????payload??????????????·?????????????check sum???????????????ò??check sum?????????????ò???跨???У??????????
????????????????У?鱣??????????????????MD5???????????????
?????ο??????
????Paper??When the CRC and TCP checksum disagree??
????The Limitations of the Ethernet CRC and TCP/IP checksums for error detection
????Amazon S3???????bit????????1?
????????????С??
??????????????綼??TCP??????￡?????TCP???????????????????????????????????????е??????????С?????????????????Android/IOS?????/?????Linux???????????м??豸/?н??豸????·??????????????????????????????????
????TCPλ???????????????????????????鷳????????????????????Щ???????????????????????????????/???????????????????????????????????????Google??????????UDPЭ??????й??????????????????????QUICЭ?飬?????UDP????????TCP???????????????????????
????????????????Э???????????????
?????????????????????????????Э?飬??????QUIC
?????????TCP/UDP?????????????????????????
????????Э?????????????????????????
????????????????????????????????????Э???????????so???
????dpdk/netmap??Packet IO??? + ??????Э?????????????????????????????
????Linux?????????????????SSH?????
???????TCP??????????????????????????????????????????????????????????Щ??????????????????????????????????????