Question & Answer
Question
When WebSphere DataPower sends a syn packet to a backend server and the backend server can't respond to the syn packet, how long will DataPower wait to sends the second syn packet?
Answer
It depends on how the back-side timeout and TCP retry values are configured.
These two values, the number of TCP retries and the back-side time out, will determine how many TCP syn packets are attempted and over how long a period of time they are attempted.
For example, if TCP retries is set to 5 (the default value) but back-side time out is set to 400 secs, the timeout will be the lesser of the two values. In this case with the 5 TCP retries, it would only take 189 seconds to complete re-transmission of the TCP syn packets.
TCP retries and the timeout at the TCP level shows the exponential relationship:
TCP Retry Packet time out(sec)
1 9 (3 + 3*2)
2 21 (3 + 3*2 + 3*2*2)
3 45
..
5 189
This information relates to TCP packet level retries. If there are further questions or issues around timeout of response content at the HTTP, MQ, or other protocol layer, review the product Information Center. Also, see What IBM DataPower timeouts are used in specific configuration methods.
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Document Information
Modified date:
08 June 2021
UID
swg21504724