Hi, In our setup we have a TCP server that continuously sends data (@35 Mbyte/sec) to a single TCP client and, after running for more than 24hours continuously, the client side stops acknowledging the messages with as a result that the server side retransmitting the data over and over again. We caught this issue using wireshark running on another Dell Server with a fast raid controller for storage. Any ideas on why the client side stops sending ACKs? A couple of keywords on our setup: . Server side: a FPGA . Client side: Dell Server (windows server 2012) with a Intel 4P I350-t network adapter . TCP client using overlapped IO Kind regard, Peter asked 05 Sep '15, 10:31  peter73 |
2 Answers:
I would say it is due to the client losing the ARP entry for the server. NB: You are receiving multicast packets for the ip.dst == 192.168.9.255 which is far away from your interface's IP address 192.168.4.100 so maybe this is a misconfiguration issue and is contributing to this problem... Regards Matthias answered 07 Sep '15, 04:00  mrEEde Thank you for your reply. What can be the reason for the client to loose the ARP entry? is there a log that shows this was the case? I'll will check the multicast from 192.168.9.255, no idea at the moment where this is coming from. Regards, Peter (07 Sep '15, 04:50) peter73 The multicast is coming one of the other interface of the the machine doing the wireshark capture, no problem there because this is not used operationally. (07 Sep '15, 08:38) peter73 |
Till packet 9 server is sending data to client on mac a0:36:9f:2b:f2:f4 and it received ack also but from packet 12 server is sending data to same client(same session) on mac a0:36:9f:2b:f2:84 and may be a different client system where that session doesnt exist,so no ack sent by this client. answered 07 Sep '15, 10:32  kishan pandey Holy smokes! I totally missed that. Thank you very much for pointing this out! (07 Sep '15, 13:07) peter73 |
Could you provide us a capture file somewhere publicly accessible, like http://www.cloudshark.org, dropbox or somwhere else, and post a link to the capture file.
I've placed an export of the capture in my dropbox, https://dl.dropboxusercontent.com/u/29942579/Retransmit_Export_2015_09_07.pcapng
Many thanks for your support, Peter