Re: [hybi] Is it important to know frame length at the start of frame? (was: Re: Discontinuation of mux ...)

[Joakim Erdfelt <[e-mail]>]

Let me see if I grok this entirely...

You are saying that HTTP/2.0 HEADERS has a 14 bit value already.
You would like to utilize this existing 14 bit value to represent websocket
payload data.
You would like to avoid having to adjust or supplement HTTP/2.0 HEADERS
just for WebSocket behaviors.
You are indicating that this 14 bit value is not a 1 to 1 representation of
"original WebSocket frame size" as determined by various APIs or extensions
before hitting the HTTP/2.0 layer.
You hint at the behavior of large (over 14 bit length) "original WebSocket
frames" being likely sent in multiple HTTP/2.0 DATA/END_SEGMENT portions.

Wouldn't this also mean that any "original WebSocket frame" length
information not being present on the receiving side. right?
The receiving side would just see HTTP/2.0 DATA/END_SEGMENT with some
indicator that the DATA is for WebSocket, right?
The receiving side would never see the "original WebSocket frame" as this
information is now lost.  Is that correct?
Instead you have HTTP/2.0 DATA length header for WebSocket payload data,
along with an END_SEGMENT indicating the separation between WebSocket
messages.


--
Joakim Erdfelt <[e-mail]>
webtide.com <http://www.webtide.com/> - intalio.com/jetty
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On Mon, Feb 24, 2014 at 11:28 AM, Takeshi Yoshino <[e-mail]>wrote:

> Thanks all for your comments.
>
> First, please note that I wanted to discuss the question in the context of
> WS/HTTP/2.0 layering. Not about redesign of RFC 6455 itself.
>
> I asked this question since the length header is the biggest field when
> encoded into HTTP/2.0 HEADERS format. Whether we can eliminate it or not in
> WS/HTTP/2.0 is one of the most important points to evaluate the plans
> employing HTTP/2.0 HEADERS.
>
> Though the ranges the length headers represent differ (HTTP/2.0: 14 bit,
> WS length format: 63 bit), it seems everyone can live without a header of
> "original WebSocket frame size".
>
> Please reply to this post if you have any objection, but please don't
> write objection to use of HTTP/2.0 HEADERS itself in this thread.
>
> Thanks
>