Random Dropped Calls

[Michael Menor]

We have a phone that is randomly dropping calls and from the Activity Logs I see multiple entries such as:

08/18/2017 10:49:35 AM - Leg L:372.1[Extn:223] is terminated: Cause: BYE from 192.168.1.36:5060

and

08/18/2017 10:45:26 AM - Leg L:375.3[Extn:223] is terminated: Cause: 487 Request Cancelled/INVITE from 192.168.1.36:5060

Does this mean that the phone is ending the call??
192.168.1.36 is the phone (Yealink T29G (yes I know it's older) and they're running on 3CX v15.5.1694.0.

Please help me decipher the Activity Logs.

 

[lneblett]

The first one is a BYE, which may or may not be normal. It depends on what caused the BYE to be issued and by which device. Not knowing this is critical as it could be that the caller was disconnected on their end and the provider sent a BYE to the PBX and then the PBX sent a BYE to the phone. The same would happen if the caller was not disconnected but simply ended the call normally. So, as stated, not enough to go on.

The CANCEL is an indication that is sent to a phone when the system has sent a SIP message to a phone, such as an INVITE, but before the phone could actually establish the call, the system sent a CANCEL to tell the phone to quit ringing. This is usually the case in a ring group where there may be more than one phone and the strategy is ring-all. When one of the member phones answers the call, the system will send the CANCEL to the others to let them know that the request (INVITE) is off the table and as a result....stop ringing.

 

[OCWI]

try unchecking pbx delivers audio under sip trunks

 

[Michael Menor]

Sorry for the late follow up. Thank you for the quick response @lneblett !!

I had another case today with this in the Activity Log. Any idea what "BYE from local" means?? I couldn't find anything on the forum regarding this.

09/12/2017 3:13:25 PM - Leg L:295.2[Line:10002>>1866xxxxxxxxx] is terminated: Cause: BYE from local
09/12/2017 3:13:25 PM - [CM503008]: Call(C:295): Call is terminated
09/12/2017 3:13:25 PM - Leg L:295.1[Extn:223] is terminated: Cause: BYE from local
09/12/2017 2:57:45 PM - [CM503007]: Call(C:295): Line:10002>>1866xxxxxxx has joined

 

[YiannisH_3CX]

That could mean that the phone or PBX terminated the call. Unfortunately we will need to see the whole call flow to determine why this happens and who is sending the BYE message. Could you please clarify what do you mean by dropped calls? Does the call get answered and it randomly drops during a conversation? Does it drop before pick up? Does it drop after a specific amount of time? Is the phone on the supported firmware? Any detail regarding the issue could help identify the cause.

 

[Michael Menor]

I understand that the Call Flow is the best way to determine what happened, but I can't have an active Packet Capture going for an indefinite amount of time, just waiting for something like this to happen. What is the best practice for this? When these issues happen its too late to troubleshoot.

The call is dropped during an active conversation. In this case it seems like it happened after 15 minutes of conversation.

 

[YiannisH_3CX]

The best practice is to run a tshark command that cuts the capture into smaller packages reducing the load on the server until the issue is replicated. If you have the ability to open a ticket for this please do so and we will provide the command for doing this. Is the phone on the supported firmware and is it running the default template? If the calls drop around the 15 minute mark it could be a re-invite from the provider that is causing this.

 

[Michael Menor]

We're currently on 3CX v15.5.1694.0 and we have Yealink T29Gs - the firmware on the Phone menu shows "Not Supported 46.81.0.60" and yes it is running the default phone template. As for the 15 minute mark - I spoke to our voice provider and they looked into the 15 minute re-invite and this was not the case.

 

[YiannisH_3CX]

The first step then is upgrading the phone to the supported firmware for your PBX version and see if the issue persists. Was the provider able to give you any insights as to why the calls disconnect? Do they see anything from their side?