Re: [quicwg/base-drafts] Disallow changes of table size after 0-RTT (#2276)

Mike Bishop <notifications@github.com> Mon, 07 January 2019 23:14 UTC

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Subject: Re: [quicwg/base-drafts] Disallow changes of table size after 0-RTT (#2276)
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I don't feel strongly about the feature itself, but this would make QPACK differ from the "increase is permitted" pattern we've created.

Assuming that SETTINGS arrives before any acknowledgements do and given that you can't evict unacknowledged entries from the dynamic table anyway, there's no way you could be wrapping under the old value of MaxEntries; increasing the max table size upon receipt of SETTINGS won't change the interpretation of anything you've sent.

The problem scenario seems to be a SETTINGS frame that's delayed past some acknowledgements on the decoder stream -- a bar on evicting anything until SETTINGS is received seems like the simplest fix.

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