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cinergi
join:2012-11-18
Canada

cinergi

Member

[Voip.ms] Ring group and IP phone call log issue

Hello,

I have a DID on voip.ms routed to a ring group that rings 2 subaccounts: an ATA and an Aastra 9480i IP phone. This setup works fine with one exception: my 9480i has not been logging any missed calls in its call log for the past month, i.e. calls that are not answered by any members of the ring group and therefore go to voice mail. It worked fine before. At first I thought it was a phone issue, but I haven't changed anything in the configuration. As a test, I routed my DID directly to the 9480i subaccount instead of going through the ring group, and it then worked as expected, i.e. missed calls were logged properly by the phone. This shows that the issue is on voip.ms' side - something related to the ring group.

I have a theory of what's going on. The 9480i does not log missed calls that are answered by another member of the ring group, i.e. it does not log missed calls when it receives a SIP CANCEL message with the text "Call completed elsewhere". This behavior makes sense because calls that are answered elsewhere are not missed calls, and I like this feature. My theory is that voip.ms has recently started sending this SIP CANCEL even when nobody answers the call, causing the phone to not log any calls.

Does anybody know whether voip.ms has recently changed something in their system? This may seem like a minor issue but it is actually very annoying because I can't know whether I've missed any calls without going into the online CDRs. It's especially frustrating because it worked fine up until approximately a month ago.

Thanks
cinergi
Stewart
join:2005-07-13

Stewart

Member

You can see what headers are being sent in both cases by using the debug (IIRC, it's called troubleshooting) feature of Aastra to send a copy of all SIP sent or received to syslog.

Or, temporarily add a softphone to the ring group and view the SIP with Wireshark.
cinergi
join:2012-11-18
Canada

cinergi

Member

Thanks, I already tried the Aastra syslog but to be honest it's a mess - it logs everything including internal function calls (for example) and is hard to follow. Good idea regarding the softphone! I'll either try that with Wireshark, or tcpdump on my router.

Thanks
cinergi
cinergi

cinergi

Member

Bingo! I did a packet capture and found the cause of the issue. When a call to my ring group times out and goes to voice mail, the SIP server sends a CANCEL with Reason: SIP;cause=200;text="Call completed elsewhere". This Reason should only be sent if one of the other ring group members answers the call, which is not the case. It therefore appears that the server is responding incorrectly. I've opened a support ticket with voip.ms.

When I call the phone directly (not going through the ring group) and let the call time out, the CANCEL message does not contain the Reason 200 message, and the missed call is displayed properly in my phone's log.

Thanks
cinergi