[BXXPwg] Flow Control again

Steve Harris sharris@primus.com
24 Jul 2000 10:05:29 -0700

JohnnyXia@acersoftech.com.cn writes:


> But "Shrinking the Window" is NOT ALLOWED in BXXP. So after a
> channel has been created, the window size is determined. It can only
> be enlarged.

I followed you well all the way to up this last bit. The window size
can in fact be reduced - without doing what we're calling "shrinking
the window." In fact, it may never be increased beyond zero after the
first 4096 octet promise.

After the first 4096 window is used up, the receiver may elect to only
open up, say, 1024 octets. That may violate the receiver-side SWS
avoidance policy if the receiver still has a buffer that will support
4096 octets. But maybe the receiver shrank its buffer to conserve
memory. If it subsequently offers up less room on its SEQ window
extensions, that's fine. So long as it never moves that right window
edge to the left, it's not short changing the sender and may use any
size window it pleases.

Steven E. Harris
Primus Knowledge Solutions, Inc.