Re: HTTP/2 extensions and proxies

It is safer to mark that the unknown frame was passed through a proxy than
to mark things as hop-by-hop and end-to-end.
The former encourages proxies to filter. The latter does not.

On Mon, Sep 30, 2013 at 4:34 AM, Amos Jeffries <> wrote:

> On 30/09/2013 7:54 p.m., Gábor Molnár wrote:
>> 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.
> 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

Received on Tuesday, 1 October 2013 15:47:44 UTC