Calls "bouncing through" Hunt Group

[David Searles]

Hi all,

I'm having a very strange random issue occurring at one of my customers...

Basic set-up where if the reception phone does not answer the call, then all the other phones in the office ring as part of the main hunt group.

Randomly, when a user tries to take the call (by picking up their handset) the line is dead, and the call jumps to another random phone. It then bounces from phone to phone with no on being able to accept the call?

I'll attach a log of a specific call it happened on this morning... the call was eventually answered by ext 122

 

[JohnS_3CX]

Hi David,

Please provide some basic information like:

3CX Version, e.g. Standard Annual 16.0.2.910
Is the 3CX Server Hosted and where?
IP Phone Make/Model/Firmware
Provisioning Method: Local / VPN / STUN / SBC
Are custom Phone Templates being used?

 

[David Searles]

Apologies - that would help wouldn't it...

3CX Version: e.g. Standard Annual 16.0.2.910
Hosted on Amazon EC2
IP Phone: Fanvil X3 (Firmware 2.10.0.6646
Provisioning Method: SBC
No custom templates are used

 

[JohnS_3CX]

You might need to run a capture for this one, if can trigger the event to happen.

Sounds like the call ends, the PBX sends a CANCEL but the end points don't receive it hence you are answering a call that already ended.

 

[David Searles]

Hmm... that might actually make some sense As it appears that the call was answered at some point...

I'll fire Wireshark up and see what that throws out.. As it's extremely random (maybe once every week or so) it's gonna be tough to identify.

 

[JohnS_3CX]

You can look into using tshark in this case, which runs constantly in the background capturing for you.

It's a little extra work but is perfect for catching random or intermittent cases like the one you have.

Install Tshark and start capture doing the below:

apt-get install tshark
mkdir pcap
chmod +7777 pcap
tshark -i 1 -b filesize:10240 -w pcap/capture.pcap

Doing the above, tshark will capture network traffic into file chunks of 10MB.

Wait for the issue to occur, and when this happens write down date/time. Stop the capture by pressing Ctrl + C.

Keep an eye on the pcap folder and delete the older files every now and then.

 

[David Searles]

Thanks for that John, I'll do just that...

I'm spending a couple of days at this particular customers office in a couple of weeks, so hopefully, I'll see this in 'real life'.

Thanks again,
David

 

[AWS2P]

how long ringing time have you set between call rings to next phone, if this randomly happen is it possible the call is picked up just in time pbx try to ring next phone, so you are with dead line ?

Or may be caller already hanged up before someone try to pickup the call

 

[Corey Logsdon]

We appear to be having a very similar issue with a 3CX installation for a client. The configuration for this situation is a bit different than the original post. There are two sites connected by vpn over fiber back to the main location where the 3CX server is located.

Very randomly at either of the two farside locations connected over vpn a phone will ring, and once picked up the call jumps from phone to phone until every one has been picked up. But there is never anyone on the line.

We have been unable go get any significant data to correlate with it happening because it occurs so randomly, sometimes once or twice a day, and sometimes we get no complaints for a week. When we do recieve a complaint so far we haven't been able to correlate anything meaningful from the logs.

 

[JohnS_3CX]

Hi Corey,

You can catch it by following the steps above. You need to look at a capture and see when the PBX sends the invite, versus when the phone acknowledges the request. If there is a significant enough time difference, it may indicate possible issues with the connection (or anything really between the PBX and the endpoint).

Provided this is indeed the case, you will see for example the phone gets the invite late, and by the time it replies back, the PBX already cancelled the ringing and moved on to the next phone, causing a chain reaction as the hunt takes place. The caller might even hang up half way through while you still have phones ringing. Without assuming too much here, it seems like a network-related issue.