3CX app using multiple SBC (in office) as well as 3CX Tunnel (outside office)

[completeware]

I have a few mobile phones which are being used in different office locations, where the local network each have a SBC for the local IP phones to connect to the 3CX server.

I have noticed that the 3CX app is using the tunnel in those locations and sometimes the quality of the call is severely affected at the locations, while the local IP phones does not experience any degradation at all.

So I was wondering if anyone have done a setup or configuration (and how), with multiple SBCs and an automated switching between using SBC (in office) and tunnel (outside office) for the 3CX app?

I guess an easy way could be to have the SBC on the same IP address in all locations, but I haven't gotten so far yet as to define a local IP address together with the 3CX tunnel FQDN in the extension configuration in the management console.

Does it make any sense at all?
Thx

 

[JohnS_3CX]

Hi,

The app is not designed to work with the SBC and the SBC is not designed to work with the app.

 

[completeware]

Hi John,

Thank you for your reply.

Whats the difference in using the SBC and no tunnel on the app, compared to using the tunnel with the app?

In my case is seems like the tunnel in the app is causing a bad voice quality and echo while the SBC is working perfect (with other IP phones). But perhaps its related to the encoding used in the app?

Best regards
Jesper

 

[JohnS_3CX]

Hi,

The app can work in two ways mainly:

A. Direct connection to the PBX IP
B. Remote connection to the PBX via FQDN - and while using the built-in tunnel

What is the SBC for then?:
Remote Desk Phones cannot use the tunnel, so for them we have the SBC which acts a local proxy, and then sends the calls via its own tunnel (effectively giving deskphones tunnel access like the mobile app has).

So the app will not use the SBC at all since it had its own tunnel capabilities. I think the reason you face issues with the app is either due to the connection (Wifi? LTE?) or sometimes it also comes down to the phone device itself (some are more well behaved than others).



Some recommendations:
1. Try to toggle the Advanced option inside the app that says "Car/Bluetooth support(Telecom API)" and make a few calls to see if your model of phone prefers it. It can make a big difference in some models of phones

2. Alternatively, edit your extension from the management console, go to provisioning, select the 3CX App and change the codec order to have this order as seen below, then reprovision your app and make some calls. This will use a little more bandwidth but you should have improved audio quality.