Incoming calls dropping at the 3 minute mark

[Michael Menor]

Has anyone experienced this issue where an incoming call would drop exactly at the 3 minute mark? This also happens when an incoming call is Parked, then picked up by the end user - it will end at the 3 minute mark. VERY FRUSTRATING!!

A little background on the setup:

• Incoming SIP trunk is provided by CallCentric
• "Support Re-Invite" is disabled under the Options tab
• 3CX v15.5 SP6

We have opened a case with CallCentric Support and this is their response (highlights are in bold):

Generally speaking, with the "Supports Re-Invite" setting disabled the 3CX trunk shouldn't forward Re-Invite packets towards the SIP trunk externally. Reviewing the example with the call from 18xx2xxxx91 on 12/9 at 20:33 GMT we can see that the same issues occurred in relevant to Re-Invite packets from 3CX:

INVITE sip:[email protected]:5060;transport=udp SIP/2.0
Via: SIP/2.0/UDP xxx.xxx.xxx.xxx:5060;branch=z9hG4bK-524287-1---44541a44216cb012;rport
Max-Forwards: 70
Contact: <sip:[email protected]:5060>
To: "John Doe" <sip:[email protected]>;tag=cj2y3Sa2FK3ZF
From: "Jane Doe"<sip:[email protected]>;tag=e22ff441
Call-ID: f26bafde-9565-1238-60b6-0010e0690d2e
CSeq: 3 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REGISTER, SUBSCRIBE, NOTIFY, REFER, INFO, MESSAGE, UPDATE
Content-Type: application/sdp
Supported: replaces, timer
User-Agent: 3CXPhoneSystem 15.5.15502.6 (15502)
Content-Length: 226

v=0
o=3cxPS 2684354560 508735520771 IN IP4 xxx.xxx.xxx.xxx
s=3cxPS Audio call
c=IN IP4 xxx.xxx.xxx.xxx
t=0 0
m=audio 9530 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=sendrecv

In addition to your example from the number 18xx2xxxx91 yesterday after you disabled the setting for Re-Invites we located a more recent example such as the call from 18xx396xxx9 today at 20:02 GMT where the 3CX is still sending our server the Re-Invite packets such as:

INVITE sip:[email protected]:5060;transport=udp SIP/2.0
Via: SIP/2.0/UDP xxx.xxx.xxx.xxx:5060;branch=z9hG4bK-524287-1---c260d415d2716837;rport
Max-Forwards: 70
Contact: <sip:[email protected]:5060>
To: "JOHN DOE" <sip:[email protected]>;tag=Kgr9avrpFZv0p
From: <sip:[email protected]>;tag=d77ace5c
Call-ID: e4dfa74f-962a-1238-1b98-0010e068b4de
CSeq: 2 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REGISTER, SUBSCRIBE, NOTIFY, REFER, INFO, MESSAGE, UPDATE
Content-Type: application/sdp
Supported: replaces, timer
User-Agent: 3CXPhoneSystem 15.5.15502.6 (15502)
Content-Length: 228

v=0
o=3cxPS 336953606144 240048406530 IN IP4 xxx.xxx.xxx.xxx
s=3cxPS Audio call
c=IN IP4 xxx.xxx.xxx.xxx
t=0 0
m=audio 9570 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=sendrecv

If possible please contact 3CX support in regard to whether it's a known bug where Re-Invite packets are still forwarded externally to the SIP trunk even with the "Supports Re-Invite" parameter disabled.

 

[eddv123]

Normally 32 seconds is the calling card of SIP ALG being enabled on the firewall. Although this is 3 minutes I would still check the firewall as it sounds like a port is being closed after a certain duration of time.

What make and model is the firewall and does the firewall checker pass inf front of 3CX ?

 

[Michael Menor]

I can confirm that SIP ALG is disabled.
This particular client has a Cisco RV320 and yes, the firewall checker does pass.

 

[eddv123]

Run a PCAP from the PBX of the call with audio proxied via the PBX, replicate the call and let's see where the BYE message is coming from.

 

[simply7]

Check your session timer value in your firewall.

 

[Michael Menor]

Another update on this. It only happens when an incoming call is parked. When the call is picked up from park, it will end at 3 minutes.

I will be checking the firewall's session timer value to see what it might be.

 

[Michael Menor]

Session timeout is set to: 1800

 

[Michael Menor]

Looking at packet #907033. Does this mean that caller "TOP / 4248" is ending the call to extension 223?



Call Flow