Re: [quicwg/base-drafts] allow PRIORITY frames referring to placeholders exceeding `SETTING_NUM_PLACEHOLDERS` (#2761)

Kazuho Oku <> Tue, 04 June 2019 03:45 UTC

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From: Kazuho Oku <>
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Subject: Re: [quicwg/base-drafts] allow PRIORITY frames referring to placeholders exceeding `SETTING_NUM_PLACEHOLDERS` (#2761)
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> However, to support your argument, it may be better to ignore all priority tree requests rather than fail e.g. half of them. And because the server doesn't know how many placeholders the client wants, it can never guess how many would be enough, ever.

Yeah. I think that the anticipation behind this PR is that a server would either support no placeholders at all, or be capable of handling enough number of placeholders. FWIW, Firefox uses 4 "placeholders" in HTTP/2. I do not think that there would be a reason for a HTTP/3 with support for placeholders to support something below 4.

Maybe we should change the recommendation of SETTINGS_NUM_PLACEHOLDERS that state "this value SHOULD be set to a non-zero value by servers" to  "this value SHOULD be set to a value equal to or greater than four" or something alike.

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