I've tried on two phone types - a 7821, and an 8841 - but the result is the same on both; sometimes the BYE message comes from the ITSP straight away, other times it takes 30 seconds (approx) for the VG to receive the BYE from the ITSP. I contacted the ITSP about it, and they're investigating why in some cases they aren't passing it on straight away. My initial thought was maybe I hadn't configured the SIP profile correctly on the VG to give them the external IP in all the correct places.

Both phones are registered to CUCM as SIP devices.

I'll have a look at getting some logs from CUCM!

It also looks pretty good, the BYE from the ITSP is sent to the CUCM by the VG right away, so it seems like the problem is not with the VG.

It would be interesting to see the messages between CUCM and the phone itself.

What kind of a device is it? 
Is it SCCP or SIP?

You could try collecting CUCM logs for a failed call and load them into translatorX, it should show us what went wrong.

If the failed call is with an SCCP device, I would try to see if it work fine with a SIP based device. It would also be easier to troubleshoot with.

Pasha.

Sure!

ITSP: 81.187.30.116 and voiceless.aa.net.uk - it appears they use the domain in the incoming invite, and the IP elsewhere.

VG202: 90.255.244.xxx is the external IP (configured by SIP profiles) and 192.168.15.222 is the internal IP

CUCM: 192.168.15.10

Thanks again for helping me with this :)

Looking at the SIP messages, when the calling PSTN party hangs up, there's a delay before the gateway receives the BYE message from the ITSP

This looks a bit messy, can you please help me combine and name some of the SIP-UAs so we could better understand the flow?

Thanks for this - I've had a look at some of the SIP messages this morning and noticed that in some places, the internal IP of the gateway was showing when it should be the external IP address. I've updated the sip profile attached to the inbound dialpeer to amend this but it still hasn't resolved the issue.

Looking at the SIP messages, when the calling PSTN party hangs up, there's a delay before the gateway receives the BYE message from the ITSP - this leads me to believe it's something to do with the SIP profile attached to the dialpeer - maybe it's initially trying to send the BYE someplace else, before not getting a response and sending it to my external IP - but I'm struggling to see where.

I've attached the sip messages from a call that doesn't disconnect from the IP phone without a delay. I've also done a deb voip ccapi inout which shows the incoming dialpeer as 200, and the outbound dialpeer as 300 - which it's meant to be, but as for the rest of the info in there, I'm not 100% sure what I'm looking for.

Any chance you could again point me in the right direction? :) If there are any other debugs that might help, let me know - I'm still getting to grips with the myriad of options!

Samuel

It's hard to say if the config is good without the logs as we don't know which dial-peers the incoming call hits and which SIP profiles kick in.

In any case, what I would be looking for in the first stage is the BYE message from the ITSP and then make sure that the VG sends it onwards to CUCM (and make sure that CUCM responds properly).

Let us know how it goes.