EX90's P-T-P Calls through VCS-C Failing

awatson20 · ‎02-01-2014

We had a weird issue yesterday that affected 4 of our EX90's on TC6.1 software at one location. We have approximately 30 EX90's deployed through out our network all on that software code. All are registered to a VCS Control. It appeared that this problem affecrted both H.323 and SIP, although most of our testing was with H.323

Call flow: 

172.31.36.29 (DN 4460015) ------ VCS 172.31.168.250 -----> 172.31.36.210 (DN 4460013)

Through debug logging we can see the VCS sending setup messages to the destination endpoint, the destination endpoint responds with the CONNECT, then VCS forwards the CONNECT message to the calling endpoint but the calling endpoint is not receiving the CONNECT and disconnects the call with "user not responding."

The endpoints we tested with first were not on the same LAN, but this problem was happening even if I did a P-T-P call to another endpoint(one of the 4) on the same subnet.

In taking packet captures from the VCS-C and the endpoints involved, we saw the calling endpoint is receiving the alerts and the CONNECT, but it does not process it.

1892     83.151546     172.31.36.29     172.31.168.250     H.225.0     1169     [TCP ACKed unseen segment] CS:
setup

A reboot of the codec ultimately fixed the problem. We had to reboot all 4 EX90's. Once rebooted, they could dial out and connect with no issues.

We talked to Cisco and they seem to think it was either network related or a software bug, but we cannot find any network related event that could have caused this. It is strange that it only affected EX90's at this one location. We were advised to upgrade to TC6.3, but I am skeptical since we have not seen this issue anywhere else but this one location. These type of problems cause us major grief with the users and lose credibility with video technology. I would appreciate any advice or input concerning this that others may have experienced. Thank you.

Wayne DeNardi · ‎02-03-2014

I've previously seen issues similar to this - the receiving end doesn't see the incoming call.

This was reported here previously - See this thread: https://supportforums.cisco.com/message/4131581.

It sounds like you're hitting the same issue: CSCum04312. This has been fixed in TC7.0.2.

Wayne
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awatson20 · ‎02-03-2014

Thanks. I saw that post. It does sound like it could be related. This is the first time I have encoutnered this with the EX90's and they have been in production for a while.

Wayne DeNardi · ‎02-03-2014

Give TC7.0.2 a go. I can confirm that it's fixed the issue on my devices (C60s, EX90s, SX20s).

As it was a new bug in the TC6.x releases (TC5.x and earlier are fine), and only occurs after a network outage (even if it's so brief your other equipment doesn't notice it), I'm not surprised you haven't seen it occur very often - it's been a semi-recent thing.

Wayne
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Nick Halbert-Lillyman · ‎02-03-2014

While it certainly sounds similar to the bug mentioned above, in my testing it only affected TC6.2 and above - TC6.1.1 and below were fine. You should note that this bug is NOT fixed in 6.3 - only fixed in 7.0.2.

One way you can try reproducing it is to unplug then re-plug the network cable. If this causes the EX90 to fail to recieve incoming calls even after re-registering, then you are probably affected by the bug.