Hi Kieran,
I have run the capture over night and i can see in the capture file that dup ack flooding is still a problem for me.
I am at a loss as to where this is comming from. Any pointers is greatly appriciated.
regards,
Martin
From: address@hidden
To: address@hidden
Subject: RE: [lwip-users] lwip 1.3.0 Duplicate ack flood problem
Date: Wed, 23 Apr 2008 12:53:25 +0200
Hi Kieran,
I have adjusted the TCP_MSS value in the lwipopts.h file, from 1536 to 1480. This seems to have affected how often dup acks are present.
Are there other values that could affect this also ?
I am currently running a capture where both TCP_WND and TCP_MSS is set to 1500. Until now i have only seen dup acks send when the TCP connection is closed
from the client side.
I will let the capture run for some time to see if, i am still plagued by dup acks being flooded. I'll keep you posted.
Regards,
Martin
From: address@hidden
To: address@hidden
Subject: RE: [lwip-users] lwip 1.3.0 Duplicate ack flood problem
Date: Tue, 22 Apr 2008 14:09:37 +0200
Hi Kieran,
I have attached the capture file to this mail. This capture file shows one ack being sent followed by 33 dup acks.
If its not possible to attach such files to this please let me know.
If you can receive the attached, please use the following display filter in wireshark:
(ip.src != 192.168.2.202 && ip.dst != 192.168.2.202) && tcp.flags.ack && tcp && (ip.src == 192.168.2.106 && ip.dst == 192.168.2.110) || (ip.src == 192.168.2.110 && ip.dst == 192.168.2.106)
and scroll down almost to the bottom of the capture.
below are the hex representation of the sequence described earlier:
1135 67.021489 192.168.2.110 192.168.2.106 TCP 52876 > http [SYN] Seq=0 Win=8192 Len=0 MSS=1460
00bd33026424001d0992c42a08004500003008d7400080060000c0a8026ec0a8026ace8c005081f175b80000000070022000864b0000020405b401010402
1136 67.027078 192.168.2.106 192.168.2.110 TCP http > 52876 [SYN, ACK] Seq=0 Ack=1 Win=1536 Len=0 MSS=1536
001d0992c42a00bd3302642408004500002cd9c90000ff065bd9c0a8026ac0a8026e0050ce8cad8c0c7e81f175b9601206008b0f0000020406002f00
1137 67.027123 192.168.2.110 192.168.2.106 TCP 52876 > http [ACK] Seq=1 Ack=1 Win=64240 Len=0
00bd33026424001d0992c42a08004500002808d8400080060000c0a8026ec0a8026ace8c005081f175b9ad8c0c7f5010faf086430000
1138 67.027766 192.168.2.110 192.168.2.106 HTTP GET /index.html HTTP/1.1
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
1140 67.060687 192.168.2.106 192.168.2.110 TCP http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9ca0000ff065bdcc0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a31800006d0000000000
1141 67.069519 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#1] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9cb0000ff065bdbc0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a3180000020000000000
1142 67.077683 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#2] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9cc0000ff065bdac0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a31800006d0000000000
1143 67.085665 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#3] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9cd0000ff065bd9c0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a3180000020000000000
1144 67.093682 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#4] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9ce0000ff065bd8c0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a31800006d0000000000
1145 67.101690 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#5] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9cf0000ff065bd7c0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a3180000020000000000
1146 67.109709 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#6] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9d00000ff065bd6c0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a31800006d0000000000
1147 67.117691 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#7] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9d10000ff065bd5c0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a3180000020000000000
...
1173 67.323976 192.168.2.106 192.168.2.110 TCP [TCP Dup ACK 1140#33] http > 52876 [ACK] Seq=1 Ack=571 Win=966 Len=0
001d0992c42a00bd33026424080045000028d9eb0000ff065bbbc0a8026ac0a8026e0050ce8cad8c0c7f81f177f3501003c6a3180000020000000000
1174 67.327842 192.168.2.106 192.168.2.110 TCP [TCP segment of a reassembled PDU]
1175 67.375113 192.168.2.106 192.168.2.110 TCP [TCP segment of a reassembled PDU]
1176 67.375172 192.168.2.110 192.168.2.106 TCP 52876 > http [ACK] Seq=571 Ack=868 Win=63373 Len=0
1177 67.376786 192.168.2.106 192.168.2.110 HTTP HTTP/1.0 200 OK (text/html)
1178 67.376848 192.168.2.110 192.168.2.106 TCP 52876 > http [ACK] Seq=571 Ack=869 Win=63373 Len=0
1179 67.383815 192.168.2.110 192.168.2.106 TCP 52876 > http [FIN, ACK] Seq=571 Ack=869 Win=63373 Len=0
1180 67.411823 192.168.2.106 192.168.2.110 TCP http > 52876 [ACK] Seq=869 Ack=572 Win=1535 Len=0
regards,
Martin
> Subject: Re: [lwip-users] lwip 1.3.0 Duplicate ack flood problem
> From: address@hidden
> To: address@hidden
> Date: Tue, 22 Apr 2008 11:50:32 +0100
>
> On Tue, 2008-04-22 at 12:40 +0200, B B wrote:
>
> > has anyone experienced something similar ?
> > or has anyone an idea, what the cause of this might be ?
> >
>
> Can you provide a binary packet capture? 600 duplicate ACKs is rather a
> lot, but a smaller number are to be expected if you have any loss on
> your network.
>
> Kieran
>
>
>
> _______________________________________________
> lwip-users mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/lwip-users
Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! Try it!
Invite your mail contacts to join your friends list with Windows Live Spaces. It's easy! Try it!
Discover the new Windows Vista Learn more!
|