Call Group Issue - One phone rings vs all phones

[GMCS]

I have a client that I setup a call group with 4 extensions. Through out the day, about 4 to 5 times, when a call comes in, only one extension will ring (the first extension in the group). Outside of those calls all phones ring like they are supposed to. I do have the phones provisioned via STUN, I will be setting up a SBC to help rule out another issue I am having that I posted in a different thread. Any suggestions? Would the SBC correct this?

 

[leejor]

It very well may be a STUN issue (all sets have been assigned a unique local SIP port, right?). Have you confirmed, using the 3CX Activity Log, that the call that only rang the one set, was a call to the ring group?

 

[GMCS]

I do not believe i set a unique local SIP port to each set. I looked at the activity log and I am seeing a lot of this for different extensions:
07/20/2021 8:38:12 AM - [CM503003]: Call(C:3808): Call to <sip:[email protected].3cx.us:0> has failed; Cause: 487 Request Terminated/INVITE from xxx.xxx.xxx.xxx:5065

I also saw this:

07/19/2021 2:56:56 PM - Call to T:RingAll:801@[Dev:sip:[email protected]:5065,Dev:sip:[email protected]:21085,Dev:sip:[email protected]:60025,Dev:sip:[email protected]:53763] from L:3734.1[Line:10000<<1xxxxxxxxxx] failed, cause: Cause: 486 Busy Here/INVITE from xxx.xxx.xxx.xxx:21085

I am using ALLOWUSEBUSYOPTFORGROUP so the users so they can see more than one call at a time when a call comes in to a group. I know it can cause some issues, but until they are comfortable with moving to a que I have to leave it for not.

I also changed the IP's to x for obvious reasons.

I think switching to a SBC would be a good start then see how things are from there.

 

[leejor]

If you've set the local SIP port of all devices, to the same port number, when using STUN, then that may cause issues. 3CX will address each set as (publicIP+port number), which means every set will look the same from outside the local LAN, not good. Some routers might be able to keep track of things, but you can't count on that.

Using an SBC should correct these problems, but, again, check the 3CX Activity Log for one of the failed calls, to see if an Invite was sent to all members of the ring group. Compare it to a log of a working call.

 

[ChrisC_3CX]

@GMCS
As leejor mentioned, the 3CX SBC is the way to go for remote IP Phones that are on the same site, especially since the existing STUN configuration was not set up as per our guides.

Also, I am obligated to tell you that modifying parameters will render the 3CX configuration unsupported. Specifically the ALLOWUSEBUSYOPTFORGROUP parameter will cause issues and will produce unexpected call flow behavior that varies from call to call making it difficult to troubleshoot and identify the root of the issue.

That said, what I recommend is to not only switch to the 3CX SBC provisioning method, but also disable the said parameter.