Each Trunk Group can have a Media Port Range
configured that indicates a range of values to use when allocating UDP ports. To provision a UDP media port range slightly larger than the actual count of ports ostensibly required to support the maximum simultaneous calls (not applicable to TCP media). The system reserves two UDP ports for each incoming UDP media call leg: one for (S)RTP and one for (S)RTCP. Thus, a configured port range must contain at least twice as many port numbers as the maximum simultaneous calls to be supported for that IPTG (not applicable to TCP media).
On SBC main screen, go to All > Zone > GW Trunk Group > Media > Media Port Range.
Select the desired Address Context, Zone and GW Trunk Group from the drop-down list to view its respective Media Port Range parameters.
The following fields are displayed:
Make the required changes and click Save at the right hand bottom of the panel to save the changes made.