I am investigating a problem that has arisen after changing a PC (updating to a new Dell PC). the operating system is windows Xp SP3.
The application software was running on the old system without any problems. The application communicates with several Agilent Digital voltmeters using the SCPI protocol over Ethernet (TCP port 5025). After the hardware was changed, the same application started to encounter frequent timeouts (as timed in the application).
I installed Wireshark on the PC and captured the Ethernet port traffic with a capture filter of
host 10.41.3.123 (and the other IP addresses of the voltmeters). The PC IP address is 10.41.8.98 and the digital voltmeter IP address is 10.41.3.123.
I notice that there are several TCP Retransmissions from the PC according to Wireshark and would like to gain second opinions as to the probable cause.
Since Wireshark indicates no intervening packets between the retries, I am concluding that the retries are being generated by the PC network card driver (or even the network card itself ?). Wireshark indicates a header checksum error on all the packets sent by the PC but I am assuming that this is because the checksum is being generated by the network card firmware or the windows driver and is not available to wireshark. The network card driver doesn't have the ability to be configured so as to disable checksum error discards.
My conclusion is that the issue is due to the PC network card since the problem was not evident when the original PC hardware was being used.
I attach a Wireshark capture log and ask for comments to either confirm or correct my conclusions.