[lwip-users] a question of tcp_ack

[刘良]

     On the project of simhost under Unix, when i set lwipopts.h TCP_WND = 4096 
,
use ->tcpdump -i tap0 ,
(server(unix):192.168.1.162:4000, client(simhost):192.168.0.2 )capture some 
data:

16:12:34.374198 192.168.1.162.4000 > 192.168.0.2.4097: . 5455872:5456896(1024) 
ack 1 win 5840 (DF)
16:12:34.374206 192.168.1.162.4000 > 192.168.0.2.4097: . 5456896:5457920(1024) 
ack 1 win 5840 (DF)
16:12:34.374210 192.168.1.162.4000 > 192.168.0.2.4097: P 5457920:5458944(1024) 
ack 1 win 5840 (DF)
16:12:34.374214 192.168.1.162.4000 > 192.168.0.2.4097: . 5458944:5459968(1024) 
ack 1 win 5840 (DF)
16:12:34.374968 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5457920 win 2048 
(DF)
16:12:34.375182 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5459968 win 0 (DF)
16:12:34.614123 192.168.1.162.4000 > 192.168.0.2.4097: . ack 1 win 5840 (DF)
16:12:34.614391 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5459968 win 4096 
(DF)
16:12:34.614434 192.168.1.162.4000 > 192.168.0.2.4097: P 5459968:5460992(1024) 
ack 1 win 5840 (DF)
16:12:34.614442 192.168.1.162.4000 > 192.168.0.2.4097: . 5460992:5462016(1024) 
ack 1 win 5840 (DF)
16:12:34.614446 192.168.1.162.4000 > 192.168.0.2.4097: . 5462016:5463040(1024) 
ack 1 win 5840 (DF)
16:12:34.614450 192.168.1.162.4000 > 192.168.0.2.4097: P 5463040:5464064(1024) 
ack 1 win 5840 (DF)
16:12:34.615222 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5462016 win 2048 
(DF)
16:12:34.615437 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5464064 win 0 (DF)
16:12:34.854113 192.168.1.162.4000 > 192.168.0.2.4097: . ack 1 win 5840 (DF)
16:12:34.854370 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5464064 win 4096 
(DF)
16:12:34.854407 192.168.1.162.4000 > 192.168.0.2.4097: . 5464064:5465088(1024) 
ack 1 win 5840 (DF)
16:12:34.854414 192.168.1.162.4000 > 192.168.0.2.4097: P 5465088:5466112(1024) 
ack 1 win 5840 (DF)
16:12:34.854418 192.168.1.162.4000 > 192.168.0.2.4097: . 5466112:5467136(1024) 
ack 1 win 5840 (DF)
16:12:34.854422 192.168.1.162.4000 > 192.168.0.2.4097: . 5467136:5468160(1024) 
ack 1 win 5840 (DF)
16:12:34.855192 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5466112 win 2048 
(DF)
16:12:34.855408 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5468160 win 0 (DF)
16:12:35.084111 192.168.1.162.4000 > 192.168.0.2.4097: . ack 1 win 5840 (DF)
16:12:35.084363 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5468160 win 4096 
(DF)
16:12:35.084401 192.168.1.162.4000 > 192.168.0.2.4097: P 5468160:5469184(1024) 
ack 1 win 5840 (DF)
16:12:35.084408 192.168.1.162.4000 > 192.168.0.2.4097: . 5469184:5470208(1024) 
ack 1 win 5840 (DF)
16:12:35.084412 192.168.1.162.4000 > 192.168.0.2.4097: P 5470208:5471232(1024) 
ack 1 win 5840 (DF)
16:12:35.084416 192.168.1.162.4000 > 192.168.0.2.4097: . 5471232:5472256(1024) 
ack 1 win 5840 (DF)
16:12:35.085168 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5470208 win 2048 
(DF)
16:12:35.085381 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5472256 win 0 (DF)
16:12:35.314111 192.168.1.162.4000 > 192.168.0.2.4097: . ack 1 win 5840 (DF)
16:12:35.314354 192.168.0.2.4097 > 192.168.1.162.4000: . ack 5472256 win 4096 
(DF)
16:12:35.314391 192.168.1.162.4000 > 192.168.0.2.4097: . 5472256:5473280(1024) 
ack 1 win 5840 (DF)

   Server send the packet: ack 1 win 5840 (DF)  costs the time too long. Can 
anyone help
me? thanks!!


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　　　　　　　　　　2004-05-18