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WAAS "TCP ACKed lost segment" message

I have deployed a couple of WAAS units across a link and have issues.

If I set everything to pass-thru, everything works OK (as no traffic is hitting any classifiers). The top line of my policy is basically a match-all pass-thru (just for testing).

All ethernet ports are nailed to 100M/FD and run with clean stats.

If I disable the pass thru rule and allow traffic to hit classifiers in my policy, I get issues for any classifiers that apply any form of acceleration.

I have captured data using tethereal on the WAE's and am seeing "TCP ACKed lost segment" messages on the ACK frame of the SYN-SYN/ACK-ACK sequence of the TCP setup. I see this on the WAN port of one of my WAE's.

Is this a symptom of a stateful firewall in my service providers network that is disrupting the WAAS discovery method ? My SP says that there are no FW's in the path, but I'm starting to wonder if I'm getting the whole story here.

The code is

If I physically back-to-back the WAE's on the bench via a test router, they work fine!

Any ideas ?


Cisco Employee

Re: WAAS "TCP ACKed lost segment" message


Do you have packet captures from both sides of the link? That's the quickest way to see of the final ACK for the optimized connection is being dropped.


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