Re: A Transport Protocol Without ACK (resend)

[Matt Wakeley <matt_wakeley@agilent.com>]

Douglas Otis wrote:

> I agree, XON/XOFF would not work.  A credit token scheme similar to FC Class
> 3 would.

FC class 3 does not have an end to end "credit token scheme".  It (class 3 bb
credit) is simply a credit mechanism between a node and it's neighbor node
(the
switch port) on whether the node can receive a frame.  This means that the
fabric has buffering inside it, and will hold onto a frame if the destination
node does not have room for it.  Thus, if the receiving node temporarily runs
out of buffers, it will withold credit from the switch port.  The sending node
doesn't know that the receiving node has run out of buffers, so the fabric
buffers fill up with undeliverable frames.

-Matt