Calls dropping after 30 mins

[celswood]

Hi all,

I am having issues with a installation whereby an outbound call to an external conferencing service is initiated, the call appears to be fine (voice ingress / egress) for the majority of the call. Then after 30 mins of the call being open the local caller will appear to hangup the call, even though the caller has not physically hung up. Checking a TCP dump of the call control the 3300 will send a BYE message to the SIP provider. Cheking the SIP ACTIVE ALL command the call still appears to be open for a short period before timing out. This happens 100% of the time and will kick the call out after 30 mins.

So far I have communicated with the SIP provider and all they can tell me is that the PBX sends the BYE message as if the call has been hung up. I have disabled session timers as the SIP provider manages the refreshing of the call but so far this issue is still happening. This is happening from both Mitel handsets and their Polycom IP 7000 SIP phone.

Mitel CX-II
Release: 6.0 PR1
Load: 12.0.0.52

Any suggestions would be welcome.

Many thanks.

 

[wireman50]

Call duration limit set in Class of Service? Either on stations or trunks?

 

[celswood]

Hi Wireman,

Thanks for the response, it seems that call duration limit is not enabled on the handsets or SIP trunk:

IP Handset:
Call Duration 10
Call Duration Forced Cleardown Timer 0
Enable Call Duration Limit on External Calls No
Enable Call Duration Limit on Internal Calls No

SIP Trunk:
Call Duration 10
Call Duration Forced Cleardown Timer 0
Enable Call Duration Limit on External Calls No
Enable Call Duration Limit on Internal Calls No

 

[wireman50]

What is the subscription period set to? If its happening on minet and SIP calls then it does kinda point to the SIP provider if you are on SIP trunking...does a normal call survive the 30 minutes timeout?

 

[celswood]

SIP Peer Timers below:

Keep-Alive (OPTIONS) Period 120
Registration Period 3600
Registration Period Refresh (%) 50
Registration Maximum Timeout 90
Session Timer 0
Subscription Period 3600
Subscription Period Minimum 300
Subscription Period Refresh (%) 80
Invite Ringing Response Timer 0

It's strange in that some normal calls will last over 30 mins, this is hard to tell becuase the users don't make many long calls apart from calling this conferencing service.

 

[wireman50]

If normal calls will last over 30 mins then I would suspect the conference service personally. Can you do a wireshark on the port to see what is happening as the 30 minutes come up? Possibly you will only need the last 5 minutes or so....

 

[celswood]

I have captured the last portion of a call from the PBX using the SIP TCPDUMP facility as this only captures the control port I can only see the BYE message from the PBX to the SIP provider. The customer is not really local and we do not have any smart hands in the area we can call out to take a capture. I will be looking to set up a test SIP peer with another third party provider to see if this is not something with the primary provider.

 

[RDECIT]

Sorry to piggy back off someone else's thread, but we are having th same problem here with a CXi II v6 software and SIP trunks. Out calls last 30/40 minutes. Spoke to provider and done some logging and we also get the PBX sending BYE.

 

[celswood]

Hi RDECIT,

I never posted the solution but it was down to the SIP voice provider not responding to polling requests from the carrier.

We also saw the PBX sending the BYE message but this was actually the user hanging up because even though the call disconnected it was the RTP stream that dropped not the SIP connection itself.

One way to check is when the call drops do you get a dial tone?

Dial tone = PBX ends the call
No dial tone = Carrier disconnects the call.