Re: [hybi] Flow control quota

[Martin Sustrik <[e-mail]>]

On 31/05/12 13:01, Arman Djusupov wrote:
> When the per-frame compression extension is being used on a logical channel,
> it is impossible to create a frame of exactly the desired size. A few bytes
> of quota will always be unutilized unless some padding is used. The mux
> specification prohibits sending frames bigger than the available quota. When
> per-frame compression is applied on the payload before mux, this payload
> cannot be fragmented any more. Even if we make compression extension mux
> aware, it cannot produce a 1 byte compressed frame, it can only flag a frame
> as uncompressed and simply send 1 byte. In general, sending 1 byte in a
> separate frame is not desirable.

That seems to suggest there's some kind of mis-layering happening here. 
Frames are used for flow control. Does it make sense to use them for 
compression as well? Shouldn't the compression rather happen on top of 
mutliplexing layer?

The situation is similar to compressing the payload in TCP packets. It 
is feasible, but in corner cases it can clash with MTU limits, cause 
re-fragmentation etc. The clean solution would be to layer compression 
on top of TCP layer.

Martin