I assume you mean SEG.ACK. It is not persistent. It does not exist, except
while processing an incoming segment. Web100 is locked out while processing a
segment so, no it can't be observed.
Unless there are reordered ACKs, SND.UNA is the same as the last received
SEG.ACK. If there is reordering, SEG.ACK will sometimes be less than SND.UNA,
and TCP knows that the segment is late.
Does this make sense? I think you want SND.UNA. BTW outside of recovery,
SND.NXT-SND.UNA is a direct measure of the TCP window size.
(John, it would have been cool to count and sum negative SEG.ACK-SND.UNA
This would yield a strong measure of return path reordering. Oh well).
Thanks,
--MM--
-------------------------------------------
Matt Mathis http://www.psc.edu/~mathis
Work:412.268.3319 Home/Cell:412.654.7529
-------------------------------------------
Evil is defined by mortals who think they know
"The Truth" and use force to apply it to others.
On Mon, 27 Aug 2007, Richard Carlson wrote:
> John;
>
> I'm wondering why the SEQ.ACK is not exposed as a Web100
> variable? Should it be?
>
> Rich
>
>
> ------------------------------------
>
>
>
> Richard A. Carlson e-mail: RCarlson@xxxxxxxxxxxxx
> Network Engineer phone: (734) 352-7043
> Internet2 fax: (734) 913-4255
> 1000 Oakbrook Dr; Suite 300
> Ann Arbor, MI 48104
>
>
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