Re: WINDOW_UPDATE with streamid = 0 redundant?

On 11 February 2014 14:33, Daniel Sommermann <dcsommer@fb.com> wrote:
> "Separate WINDOW_UPDATE frames are sent for the stream and connection level
> flow control windows. "
>
> It seems that we don't usually need a separate WINDOW_UPDATE for the
> connection (with streamid = 0). When a particular stream gets processed, we
> send a WINDOW_UPDATE for that stream, but doesn't this also imply that the
> connection-level window should also be updated? When would a WINDOW_UPDATE
> for a stream NOT imply an update on the connection window?
>
> I can see keeping around WINDOW_UPDATE with streamid = 0 for the case where
> you want to increase only the connection window size at the beginning of the
> connection, but after that setup, it seems like a waste of bandwidth to send
> these extra WINDOW_UPDATE frames for the connection window.
>
> Thoughts?

There are two layers of flow control windows, one per stream, and a
single connection-level window.

WINDOW_UPDATE on stream 0 increases the space advertised on the
connection-level window.  It's critical to protocol operation that
this be separately updated to the stream-level windows.

Received on Tuesday, 11 February 2014 22:40:45 UTC