单个报文段超过MSS大小

MTU：maximum transmission unit，最大传输单元，由硬件规定，如以太网的MTU为1500字节。

MSS：maximum segment size，最大分节大小，为TCP数据包每次传输的最大数据分段大小，

一般由发送端向对端TCP通知对端在每个分节中能发送的最大TCP数据。

MSS值为MTU值减去IPv4 Header（20 Byte）和TCP header（20 Byte）得到。


node1发送到node2:

22:37:31.588659 IP node1.47322 > node2.discard: Flags [S], seq 1368220320, win 2560, options [mss 256,sackOK,TS val 25983697 ecr 0,nop,wscale 6], length 0
22:37:31.588901 IP node2.discard > node1.47322: Flags [S.], seq 2351798279, ack 1368220321, win 2440, options [mss 256,sackOK,TS val 239126 ecr 25983697,nop,wscale 7], length 0
22:37:31.588995 IP node1.47322 > node2.discard: Flags [.], ack 2351798280, win 40, options [nop,nop,TS val 25983698 ecr 239126], length 0


22:37:31.589371 IP node1.47322 > node2.discard: Flags [.], seq 1368220321:1368221297, ack 2351798280, win 40, options [nop,nop,TS val 25983698 ecr 239126], length 976
22:37:31.589439 IP node1.47322 > node2.discard: Flags [P.], seq 1368221297:1368221345, ack 2351798280, win 40, options [nop,nop,TS val 25983698 ecr 239126], length 48
22:37:31.589489 IP node1.47322 > node2.discard: Flags [.], seq 1368221345:1368222321, ack 2351798280, win 40, options [nop,nop,TS val 25983698 ecr 239126], length 976
22:37:31.589545 IP node1.47322 > node2.discard: Flags [.], seq 1368222321:1368222565, ack 2351798280, win 40, options [nop,nop,TS val 25983698 ecr 239126], length 244

22:37:31.590569 IP node2.discard > node1.47322: Flags [.], ack 1368220565, win 23, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.590660 IP node2.discard > node1.47322: Flags [.], ack 1368220809, win 27, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.590683 IP node1.47322 > node2.discard: Flags [.], seq 1368222565:1368223541, ack 2351798280, win 40, options [nop,nop,TS val 25983699 ecr 239127], length 976
22:37:31.591014 IP node2.discard > node1.47322: Flags [.], ack 1368221053, win 31, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591030 IP node1.47322 > node2.discard: Flags [.], seq 1368223541:1368223785, ack 2351798280, win 40, options [nop,nop,TS val 25983700 ecr 239127], length 244
22:37:31.591090 IP node2.discard > node1.47322: Flags [.], ack 1368221297, win 35, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591102 IP node2.discard > node1.47322: Flags [.], ack 1368221345, win 35, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591111 IP node1.47322 > node2.discard: Flags [.], seq 1368223785:1368225005, ack 2351798280, win 40, options [nop,nop,TS val 25983700 ecr 239127], length 1220
22:37:31.591188 IP node2.discard > node1.47322: Flags [.], ack 1368221589, win 39, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591241 IP node2.discard > node1.47322: Flags [.], ack 1368221833, win 42, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591250 IP node2.discard > node1.47322: Flags [.], ack 1368222077, win 46, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591257 IP node1.47322 > node2.discard: Flags [.], seq 1368225005:1368226225, ack 2351798280, win 40, options [nop,nop,TS val 25983700 ecr 239127], length 1220
22:37:31.591323 IP node2.discard > node1.47322: Flags [.], ack 1368222321, win 50, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.591332 IP node2.discard > node1.47322: Flags [.], ack 1368222565, win 54, options [nop,nop,TS val 239127 ecr 25983698], length 0
22:37:31.594570 IP node2.discard > node1.47322: Flags [.], ack 1368222809, win 58, options [nop,nop,TS val 239131 ecr 25983699], length 0
22:37:31.594603 IP node1.47322 > node2.discard: Flags [.], seq 1368226225:1368226957, ack 2351798280, win 40, options [nop,nop,TS val 25983703 ecr 239131], length 732
22:37:31.594685 IP node2.discard > node1.47322: Flags [.], ack 1368223053, win 61, options [nop,nop,TS val 239131 ecr 25983699], length 0
22:37:31.594696 IP node2.discard > node1.47322: Flags [.], ack 1368223297, win 65, options [nop,nop,TS val 239131 ecr 25983699], length 0
22:37:31.594703 IP node1.47322 > node2.discard: Flags [.], seq 1368226957:1368227445, ack 2351798280, win 40, options [nop,nop,TS val 25983703 ecr 239131], length 488
22:37:31.594761 IP node2.discard > node1.47322: Flags [.], ack 1368223541, win 69, options [nop,nop,TS val 239131 ecr 25983699], length 0
22:37:31.594878 IP node2.discard > node1.47322: Flags [.], ack 1368223785, win 73, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.594885 IP node2.discard > node1.47322: Flags [.], ack 1368224029, win 77, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.594889 IP node2.discard > node1.47322: Flags [.], ack 1368224273, win 81, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.594893 IP node2.discard > node1.47322: Flags [.], ack 1368224517, win 84, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.594904 IP node1.47322 > node2.discard: Flags [.], seq 1368227445:1368228665, ack 2351798280, win 40, options [nop,nop,TS val 25983703 ecr 239131], length 1220
22:37:31.595728 IP node2.discard > node1.47322: Flags [.], ack 1368224761, win 88, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595740 IP node2.discard > node1.47322: Flags [.], ack 1368225005, win 92, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595745 IP node2.discard > node1.47322: Flags [.], ack 1368225249, win 96, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595749 IP node2.discard > node1.47322: Flags [.], ack 1368225493, win 100, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595753 IP node2.discard > node1.47322: Flags [.], ack 1368225737, win 103, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595757 IP node2.discard > node1.47322: Flags [.], ack 1368225981, win 107, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595762 IP node2.discard > node1.47322: Flags [.], ack 1368226225, win 111, options [nop,nop,TS val 239131 ecr 25983700], length 0
22:37:31.595801 IP node2.discard > node1.47322: Flags [.], ack 1368226469, win 115, options [nop,nop,TS val 239131 ecr 25983703], length 0
22:37:31.595833 IP node2.discard > node1.47322: Flags [.], ack 1368226713, win 119, options [nop,nop,TS val 239131 ecr 25983703], length 0
22:37:31.595839 IP node2.discard > node1.47322: Flags [.], ack 1368226957, win 122, options [nop,nop,TS val 239132 ecr 25983703], length 0
22:37:31.595843 IP node2.discard > node1.47322: Flags [.], ack 1368227201, win 125, options [nop,nop,TS val 239132 ecr 25983703], length 0
22:37:31.595909 IP node1.47322 > node2.discard: Flags [.], seq 1368228665:1368229885, ack 2351798280, win 40, options [nop,nop,TS val 25983704 ecr 239132], length 1220
22:37:31.596085 IP node1.47322 > node2.discard: Flags [.], seq 1368229885:1368231593, ack 2351798280, win 40, options [nop,nop,TS val 25983705 ecr 239132], length 1708
22:37:31.597604 IP node2.discard > node1.47322: Flags [.], ack 1368229885, win 130, options [nop,nop,TS val 239134 ecr 25983703], length 0
22:37:31.597640 IP node1.47322 > node2.discard: Flags [.], seq 1368231593:1368231837, ack 2351798280, win 40, options [nop,nop,TS val 25983706 ecr 239134], length 244
22:37:31.597721 IP node1.47322 > node2.discard: Flags [.], seq 1368231837:1368233789, ack 2351798280, win 40, options [nop,nop,TS val 25983706 ecr 239134], length 1952
22:37:31.599435 IP node2.discard > node1.47322: Flags [.], ack 1368230129, win 134, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599526 IP node2.discard > node1.47322: Flags [.], ack 1368230373, win 138, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599541 IP node2.discard > node1.47322: Flags [.], ack 1368230617, win 142, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599559 IP node2.discard > node1.47322: Flags [.], ack 1368230861, win 145, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599565 IP node2.discard > node1.47322: Flags [.], ack 1368231105, win 149, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599568 IP node2.discard > node1.47322: Flags [.], ack 1368231349, win 153, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599574 IP node2.discard > node1.47322: Flags [.], ack 1368231593, win 157, options [nop,nop,TS val 239134 ecr 25983705], length 0
22:37:31.599580 IP node2.discard > node1.47322: Flags [.], ack 1368231837, win 161, options [nop,nop,TS val 239134 ecr 25983706], length 0
22:37:31.599585 IP node2.discard > node1.47322: Flags [.], ack 1368232081, win 164, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599591 IP node2.discard > node1.47322: Flags [.], ack 1368232325, win 168, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599596 IP node2.discard > node1.47322: Flags [.], ack 1368232569, win 172, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599599 IP node2.discard > node1.47322: Flags [.], ack 1368232813, win 176, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599603 IP node2.discard > node1.47322: Flags [.], ack 1368233057, win 180, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599607 IP node2.discard > node1.47322: Flags [.], ack 1368233301, win 183, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599620 IP node2.discard > node1.47322: Flags [.], ack 1368233545, win 187, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599636 IP node2.discard > node1.47322: Flags [.], ack 1368233789, win 191, options [nop,nop,TS val 239135 ecr 25983706], length 0
22:37:31.599692 IP node1.47322 > node2.discard: Flags [.], seq 1368233789:1368235741, ack 2351798280, win 40, options [nop,nop,TS val 25983708 ecr 239135], length 1952
22:37:31.599800 IP node1.47322 > node2.discard: Flags [.], seq 1368235741:1368237693, ack 2351798280, win 40, options [nop,nop,TS val 25983708 ecr 239135], length 1952
22:37:31.601887 IP node2.discard > node1.47322: Flags [.], ack 1368234033, win 195, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.601903 IP node1.47322 > node2.discard: Flags [.], seq 1368237693:1368238669, ack 2351798280, win 40, options [nop,nop,TS val 25983711 ecr 239138], length 976
22:37:31.601955 IP node2.discard > node1.47322: Flags [.], ack 1368234277, win 199, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.601981 IP node2.discard > node1.47322: Flags [.], ack 1368234521, win 203, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.601984 IP node2.discard > node1.47322: Flags [.], ack 1368234765, win 206, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.601986 IP node2.discard > node1.47322: Flags [.], ack 1368235009, win 210, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.601990 IP node1.47322 > node2.discard: Flags [.], seq 1368238669:1368239645, ack 2351798280, win 40, options [nop,nop,TS val 25983711 ecr 239138], length 976
22:37:31.602023 IP node2.discard > node1.47322: Flags [.], ack 1368235253, win 214, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602057 IP node2.discard > node1.47322: Flags [.], ack 1368235497, win 218, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602061 IP node2.discard > node1.47322: Flags [.], ack 1368235741, win 222, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602064 IP node2.discard > node1.47322: Flags [.], ack 1368235985, win 225, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602067 IP node2.discard > node1.47322: Flags [.], ack 1368236229, win 229, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602111 IP node2.discard > node1.47322: Flags [.], ack 1368236473, win 233, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602216 IP node2.discard > node1.47322: Flags [.], ack 1368236717, win 237, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602224 IP node1.47322 > node2.discard: Flags [P.], seq 1368239645:1368241597, ack 2351798280, win 40, options [nop,nop,TS val 25983711 ecr 239138], length 1952
22:37:31.602266 IP node2.discard > node1.47322: Flags [.], ack 1368236961, win 241, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602270 IP node2.discard > node1.47322: Flags [.], ack 1368237205, win 244, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602273 IP node2.discard > node1.47322: Flags [.], ack 1368237449, win 248, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602299 IP node2.discard > node1.47322: Flags [.], ack 1368237693, win 252, options [nop,nop,TS val 239138 ecr 25983708], length 0
22:37:31.602310 IP node2.discard > node1.47322: Flags [.], ack 1368237937, win 256, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602314 IP node2.discard > node1.47322: Flags [.], ack 1368238181, win 260, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602316 IP node2.discard > node1.47322: Flags [.], ack 1368238425, win 264, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602319 IP node2.discard > node1.47322: Flags [.], ack 1368238669, win 267, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602321 IP node2.discard > node1.47322: Flags [.], ack 1368238913, win 271, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602323 IP node2.discard > node1.47322: Flags [.], ack 1368239157, win 275, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602325 IP node2.discard > node1.47322: Flags [.], ack 1368239401, win 279, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602327 IP node2.discard > node1.47322: Flags [.], ack 1368239645, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.602353 IP node1.47322 > node2.discard: Flags [.], seq 1368241597:1368243061, ack 2351798280, win 40, options [nop,nop,TS val 25983711 ecr 239139], length 1464
22:37:31.602399 IP node1.47322 > node2.discard: Flags [.], seq 1368243061:1368244525, ack 2351798280, win 40, options [nop,nop,TS val 25983711 ecr 239139], length 1464
22:37:31.603241 IP node2.discard > node1.47322: Flags [.], ack 1368240133, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603251 IP node2.discard > node1.47322: Flags [.], ack 1368240621, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603256 IP node2.discard > node1.47322: Flags [.], ack 1368241109, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603263 IP node1.47322 > node2.discard: Flags [.], seq 1368244525:1368245989, ack 2351798280, win 40, options [nop,nop,TS val 25983712 ecr 239139], length 1464
22:37:31.603309 IP node2.discard > node1.47322: Flags [.], ack 1368241597, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603314 IP node2.discard > node1.47322: Flags [.], ack 1368242085, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603316 IP node2.discard > node1.47322: Flags [.], ack 1368242573, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603319 IP node1.47322 > node2.discard: Flags [.], seq 1368245989:1368247453, ack 2351798280, win 40, options [nop,nop,TS val 25983712 ecr 239139], length 1464
22:37:31.603349 IP node2.discard > node1.47322: Flags [.], ack 1368243061, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603353 IP node2.discard > node1.47322: Flags [.], ack 1368243549, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603355 IP node2.discard > node1.47322: Flags [.], ack 1368244037, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603358 IP node1.47322 > node2.discard: Flags [.], seq 1368247453:1368248917, ack 2351798280, win 40, options [nop,nop,TS val 25983712 ecr 239139], length 1464
22:37:31.603386 IP node2.discard > node1.47322: Flags [.], ack 1368244525, win 283, options [nop,nop,TS val 239139 ecr 25983711], length 0
22:37:31.603824 IP node2.discard > node1.47322: Flags [.], ack 1368245013, win 283, options [nop,nop,TS val 239140 ecr 25983712], length 0
22:37:31.603833 IP node2.discard > node1.47322: Flags [.], ack 1368245501, win 283, options [nop,nop,TS val 239140 ecr 25983712], length 0
22:37:31.621334 IP node2.discard > node1.47322: Flags [F.], seq 2351798280, ack 1368253090, win 283, options [nop,nop,TS val 239158 ecr 25983714], length 0
22:37:31.621382 IP node1.47322 > node2.discard: Flags [.], ack 2351798281, win 40, options [nop,nop,TS val 25983730 ecr 239158], length 0
^C