Aatrox Communications works with customers and partners to make sure the initial deployment of your 3CX phone system is going to be reliable and maintainable moving forward.
Through many deployments we have learnt the pain points of maintaining phone system solutions. We have found that if done properly 3CX give you the tools to run a maintainable phone system.
One of the tools which 3CX offer to use with their phone systems is what they call a “Session Border Controller” or “SBC”, a SBC is a lightweight Microsoft Windows program which dials a tunnel from the PC the SBC is installed on to the 3CX Cloud Instance.
We suggest that you think of it as a Site to Site VPN which only transfers voice traffic from the SBC Window machine to the 3CX Cloud Instance. It also encrypts your voice traffic as it is transferred from onsite to the 3CX Cloud Instance.
It dials a tunnel on port 5090 (this is the default tunnel port which can be changed if needed), and then discovers all the phones on the network so that they are discoverable, can be assigned to extensions and provisioned from the 3CX Cloud Instance’s Management Console.
The SBC overcomes the majority of Firewall, NAT, and ISPs that block VoIP traffic. The only port which needs to be open is the tunnel port which forwards to the 3CX Cloud Instance. One thing that is recommended is that you setup a monitoring agent of some kind to watch the SBC service on the Windows machine to make sure that it is still running, because if it stops then so will all of the devices relying on it.
A major advantage of the SBC over STUN is that you don’t need to forward ports to use advanced features such as CTI Mode on the softphone. If you want to use CTI Mode with STUN when your 3CX Instance is hosted in the cloud, you will need to:
- Set each phone a local static IP
- Forward ports on the onsite firewall
- Set the ports of the phone on 3CX extension
It is much easier to deploy a SBC than configure the above for each and every phone configured using STUN.
Deploying 3CX on the right infrastructure and connecting the phones in the right method is the difference between having a maintainable solution and not.
Aatrox Communications is here to assist in advising, deploying solutions for customers and partners. Don’t hesitate to get in touch.
April 7, 2023
Phone System 