Peer Trunking GXW42xx FXS Extensions with a Session Border Controller (SBC)

This article explains how to setup a Grandstream GXW4216/32/48 port analog gateway for use with a Session Border Controller or PBX via Peer Trunking (where FXS ports are not registering back to the SBC or PBX).

1. Login to the GXW42xx and specify the IP address of your SBC/PBX in the SIP Server field (this is where your outbound calls from your FXS ports will be directed to) and save changes:
   
   
   
2. Enable 'Use Request Routing ID in SIP Headers under Profiles > Profile 1 > SIP Settings > Basic Settings to use the Routing ID specified on the FXS port (i.e. the caller id of the outbound call will use the number specified on FXS Ports > Advanced Port Settings > FXS1-16 > Request URI Routing ID):
   
   
   
3. Assign your numbers/extensions to the appropriate FXS ports (FXS Ports > Port Settings > FXS 1-16):
   
   
   
4. Set the Hunting Group and Request URI Routing ID for each port configured. This will route calls destined for 0331234001 to FXS1 and FXS3 (based on the Hunting Group Type specified) and 031234002 to FXS2:
   
   
   
5. Make some test calls and expect the following results:
   

   Call from	Call to	Port
   External	031234001	FXS1 followed by FXS3 after Hunting Group Ring Timeout occurs
   External	031234002	FXS2
   031234001	External	FXS1
   031234002	External	FXS2

   
   Notes:
   All internal calls between extensions will be routed via the SBC/PBX (not directly from port to port). Please ensure your SBC/PBX is configured correctly to route calls between extensions.