Forum Discussion
CirrusSlowness issue / tcp window
Hi all
There is a slowness issue I am diagnosing with a url hosted on ltm in data center. The url is a plain vip on 443 which has tcp, client ssl & default server profile.
While I did tcpdump on vip & pool members on 443, i see there are tcp window full, tcp window zero & tcp window update sent from pool member to vip/snat ip.
Please advise if these tcp window messages indicate or message of slow performance.
Dylan_375544Cirrocumulus
It sounds like the back end server may be being over loaded.
If a window size is 0, that means that the buffer is full and the server cant receive any more data.
HERE is some more info from wireshark.
Hope that helps! If it does please up-vote and select this answer, it'd be greatly appreciated!
-Dylan
Andy_304337Hi Dylan
Thank you for your response and a happy new year.
Agree with tcp zero window. But how do we continue to investigate with tcp full window & tcp window update ?
- Dylan_375544
Is this a VIP that has been working fine before and is now encountering this error? Or is this a new VIP?
One thing I would look at is the system resource usage on the backend server and make sure they aren't being over loaded.