Foundry F5 load balancer fails H2 priorization test

[Schepp]

Summary

Foundry F5 load balancer fails HTTP/2 priorization test

Server / CDN etc.

Foundry F5

Browser

Desktop Chrome on 3G via Webpagetest

Link to WebPageTest result

https://webpagetest.org/result/191123_46_0726dd35ed3895eee67d74dc85d58146/

Link to upstream bug report

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[andydavies]

Thank You!

I need to repeat the test on 3G Fast but having a working URL helps!

@pmeenan Any ideas why Chrome gives the last two requests on this test LOWEST priority, even on 3G Fast?

https://webpagetest.org/result/191128_GN_f5be7638e6f688d1202093cc72a5efe9/1/details/#waterfall_view_step1

[Schepp]

You are welcome! We are right now trying to figure out, what version our site uses and if there is potential for misconfiguration. Sadly I'm sitting in a company with a DevOps mindset, meaning that all these processes take way longer and are more complicated than they should be. If we can narrow down the reasons as to when F5 fails, I'll open a new issue with more details.

[pmeenan]

Wow, the F5's are even more broken than prioritization. Looks like they limit HTTP/2 to 10 concurrent streams:

    "http2_server_settings": {
        "SETTINGS_MAX_HEADER_LIST_SIZE": 32768,
        "SETTINGS_MAX_CONCURRENT_STREAMS": 10,
        "SETTINGS_INITIAL_WINDOW_SIZE": 32768
    },

Requests #16 and 28 were the higher-priority requests in this case instead of the last 2 because the prioritization was done on the client since only 10 streams were in flight at a time.