Hi, I have received a wireshark log. Some of the queries are marked [Retransmission....]. When logging in the lab, and delaying the response to above timeout-limit. I get a new query with the same trans-ID, but it is not marked [Retransmission.....]. Could this action be triggered by something different? BR Frenzie asked 19 May '14, 06:01  Frenzie |
One Answer:
Your forced new query probably does not have the same sequence number as the original one. You should compare the TCP layers of both packets to see if the sequence numbers are identical or not - if they're different you're not seeing a TCP retransmission, just an "application retransmission". Retransmissions usually occur due to packet loss, which is not easy to recreate in a lab environment - at least not in a very exact kind of way. answered 19 May '14, 06:10  Jasper ♦♦ |
Thank you for your answer. But this leads to another one: Where/how can I set the parameters for these retransmissions?
What kind of parameters do you mean? If a segment is lost it is retransmitted, so if the receiver tells the sender that there is a gap in the packets it will trigger a retransmit at the sender. These mechanisms are more or less hard coded into the TCP stacks of each OS.