Subject: HTTP/2 extensions and proxies

From: Gábor Molnár <[email-masked]>
Date: Mon, 30 Sep 2013 08:54:07 +0200

Currently, "Implementations MUST ignore frames of unsupported or
unrecognized types.". As far as I see, the point of this is to enable
the extension of the protocol in a backwards compatible way.

But what about proxies? Should they ignore unrecognized frames too, or
should they forward them? If they drop every unknown frame, it is not
possible to specify end-to-end extensions. Is this constraint
intentional? I think that end-to-end extensions would be useful, too,
e.g. WebSockets over HTTP2 if a HTTP2 proxy does not support
WebSockets explicitly.

  Gábor

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From: Amos Jeffries <[email-masked]>
Date: Tue, 01 Oct 2013 00:34:30 +1300

> e.g. WebSockets over HTTP2 if a HTTP2 proxy does not support

And if they pass all unknown frames it will not be possible to develope 
future hop-by-hop extensions.

I think there needs to be a flag indicating which group the frame 
belongs to or splitting the frame type value range into two segments.
I suggest the uppermost bit of the frame type value be set to 1 on 
end-to-end frames.

Amos