CallCentric Transport Protocol

[VISA MC]

Today we lost the ability for outbound calls, we had other internet issues today so I didn't think anything of it. It was affecting our cell phones as well. I contacted CallCentric and sent them a log file as it appeared to be on their end and they said we were trying to call using TCP instead of UDP. Looking at the options in the SIP Trunk for CallCentric it has changed to ANY for transport protocol. Changing back to UDP has resolved this. I'm not sure how or when this would have gotten changed as we haven't been in these settings since we set up the trunk. I can only assume an update caused this change - someone might want to look at this before it gets too far out there.

 

[VISA MC]

Interesting.
I just updated another customer account of ours:

The option is not listed under SIP Trunks > Options.
Their PBX version number is 16.0.1581 upgraded to 16.0.676 and installed several CallCentric updates, it appeared as an option under SIP Trunks > Options and is defaulted to Any.

 

[eddv123]

We use Gamma and it is the same for their trunks with this version (I just checked) I think chances are they will be for most.

Surely "Any" covers all the versions (TCP/UDP/TLS) and I would of thought it would adjust to what is being sent to/from the trunk.

Have you confirmed what the other legs of the call are sending (endpoint to PBX for example). I would run a PCAP from the PBX and investigate with Wireshark: https://www.3cx.com/docs/capture-network-traffic/

 

[VISA MC]

I did not because those calls had no issues. Inbound worked fine and extension to extension worked fine. We have been on 3CX for almost a year and made no changes aside from the update.

 

[JohnS_3CX]

Hi @VISA MC

Without a capture this remains an unknown.

Any = asks provider to tell the PBX all the methods they support, and which they prefer to use

UDP = only asks provider to tell the PBX if they support UDP (so more restrictive)

Notice that in both cases, it will ask the provider (this is why my test PBX with Callcentric works with "any" when I test it). I suggest you set it back to any and test it again after allowing it a moment to re-register.