Re: HTTP/2 and Websockets

On 26 November 2014 05:17:41 GMT+08:00, Martin Thomson <martin.thomson@gmail.com> wrote:
>On 25 November 2014 at 11:55, Jason Greene <jason.greene@redhat.com>
>wrote:
>>
>> What is the benefit to preventing reframing? The negative of such a
>restriction is that intermediaries will be unable to utilize their
>knowledge of their network topology to improve performance.
>
>
>It would appear that Yukata and Andy want to use HTTP/2 frame
>boundaries as the basis for WS frame boundaries.  That implies that
>you need to prevent blind reframing.  Since reframing is an inherent
>part of HTTP/2, I note that this would be unwise.  (And for more than
>just the reasons you describe.)

Nah.

Like http2 framing, ws framing is perfectly fungible with no guarantees that what was sent is what is received, other than for the payload to be the right total amount eventually and in the right order.  Ws is also fine with frame fragmentation during transport as much as you like.

Since in the scheme described the DATA frame is the ws frame, fragmenting the DATA at the same time fragments the ws frame which is fine.

The only problem is we stuck the ws frame flags byte at the start of the DATA / ws frame.  If that's how it is, then the fragmentation action has to understand the stream upgraded to ws and manage adding / removing that extra byte when splitting or combining DATA.

If you have a suggestion for getting rid of the extra byte and just having pure ws payload in the DATA, that would make it completely transparent for http2 fragmentation.

-Andy

Received on Wednesday, 26 November 2014 01:29:02 UTC