WebPagetest Forums
How to find initcwnd from the test result ? - Printable Version

+- WebPagetest Forums (https://www.webpagetest.org/forums)
+-- Forum: WebPagetest (/forumdisplay.php?fid=7)
+--- Forum: General Discussion (/forumdisplay.php?fid=25)
+--- Thread: How to find initcwnd from the test result ? (/showthread.php?tid=15928)



How to find initcwnd from the test result ? - durai_raj_kumar - 10-22-2019 04:25 AM

Hi

I am new to this webpage testing site, where I am trying to interpret and find the initcwnd value configured on the web page hosted server.

Is that possible to check ? If yes, please let me know me how and where can I find this value.

Thank you in advance

Regards
Durai


RE: How to find initcwnd from the test result ? - pmeenan - 10-23-2019 12:22 AM

No, it isn't a metric that is easily measured from the outside. You can try to infer it by testing a large static file (like an image) over http (not https) with a connection that has high bandwidth and high RTT (like 5Mbps + 500ms RTT) and with tcpdump enabled. They you need to look at the tcpdump and see how many packets are sent in the first round, how many in the second, etc.

It has to be http otherwise the certificate exchange will warm up the connection.


RE: How to find initcwnd from the test result ? - durai_raj_kumar - 11-17-2019 03:51 AM

Thank you for the reply

Unfortunately, my test results are all HTTPS

Anyway, Thanks again