Solved Session Boarder Controller

[stephan23]

We were having some rare issues with our phones ( we host with 3CX ).

It was suggested to me to install an SBC.

When educating myself about this ( on this page https://www.3cx.com/docs/3cx-tunnel-session-border-controller/ )I read the following.

Internal calls between phones located on the same network will be set-up directly with each other, without going via the internet link, resulting in improved voice quality.

So it says that internal calls will be set-up directly without going via the internet link.

How will that affect the usage of 3cx apps?

Some employees have desk phones but also use the app when they are out and about. At the moment if they get a call, both phones ring and the employees can choose which phone they want to use ( if they are at their desk ).

If the calls will be set-up directly, will this still be the case?

Also some employees take their phones home to work from home? Will using the SBC require any setting changes in order for the phones to work from home?

Thanks,

 

[Alphabetic]

3CX apps use the tunnel irrelevant to your onsite sbc. Only the handsets using the SBC as their proxy will call directly when doing internal calls

 

[stephan23]

Sorry, I am a total newbie with 3cx and telecoms.

I do understand that only the physical phones will go through the SBC. But I am still not sure if the mobiles with the 3cx app will ring along with the physical phone when an internal call is calling the extension as it says that internal calls will be connected directly without the need to go via the internet link. If there isn't the internet link, how will the pbx know that there is a call being made? And if it doesn't know if a call is being made, how can it tell the 3cx app to ring?

Or is my understanding of how the whole thing works completely wrong?

 

[Alphabetic]

As long as the extensions in the 3cx app/phone/web client are registered then all devices where the extension is registered will be able to make and receive calls.

The SBC is used to send signalling and audio traffic back and forth between PBX and SBC without the need to open ports etc.

When an internal call is made between endpoints behind the same SBC then the PBX tells the endpoints to send the traffic between themselves instead of going out to the PBX and back to the endpoints.

If you have no internet your SBC will not register and then none of your phones will work.

 

[stephan23]

Ah ok, that makes sense. thanks.