3CX includes the 3CX Session Border Controller (SBC) which allows easier bridging of remote 3CX instances and connection of remote extensions. The 3CX SBC combines all SIP (signaling) and RTP (media) VoIP Packets from one location and delivers them to and from another location (typically the PBX Server) using a custom TCP protocol.
This simple concept allows 3CX to overcome firewall or telecom provider issues. The 3CX SBC can be used for the following reasons:
The image above demonstrates how the 3CX SBC works. In this example, 3CX Phone System is on IP Address 10.0.0.181, and listens on TCP port 5090 (by default) for incoming Tunnel traffic. We must set up a single Port Forwarding rule on the NAT/Firewall Device, telling it that all incoming TCP and UDP traffic received on port 5090 should be delivered to LAN IP Address 10.0.0.181.
The remote setup is shown on the left hand side of the cloud. In this example, the machine with IP address of 192.168.0.2 has the 3CX app installed. We will need to tell the VoIP Phone the public IP address of the PBX Server (which in this case is 220.127.116.11), and also the private IP address of the PBX Server (which in this case is 10.0.0.181). Since the 3CX app will by default use the standard port numbers used by 3CX, typically no further configuration is necessary.
The 3CX SBC can be used in the following scenarios:
2* USB 2.0 for external storage or disaster recovery system
2 (100Mbps speed)
3CX SBC Pre installed