The Media System Configuration contains system-wide settings for the Media System, configuring the media system means setting the number of RTP/RTCP port pairs and the starting port. Other aspects of media handling, such as Media Profiles, Lists, and Managing SDES-SRTP Profiles are handled in different sections of the UI and are explained on their own topic pages.
UDP ports are used for transmission of VoIP calls employing RTP protocols (RTP over UDP). The start port is the first port that can be used for a call. Calls require a pair of ports, one for the voice the other for the control information (RTP/RTCP). The number of port pairs determines the number of simultaneous IP Call Legs on the SBC Edge (SBC). For example; if you have 100 pairs, you can have a maximum of 100 simultaneous IP Call Legs. This does not affect the number of TDM/TDM calls.
Port Pair Considerations
For SWe Lite Release 7.0 and later only: The number of RTP Port Pairs must be configured slightly larger than the actual number of ports required to support the projected number of calls. We recommend you over-allocate the number of port pairs by approximately 25 - 30% above the number of calls you want to support.
Projected Number of Calls
Approximate Number of Port Pairs
|100 sessions||250||Audio calls only *|
|1000 sessions||2500||Audio calls only *|
How Ping Affects Media
The SBC periodically (approximately every 30 seconds) pings all the media endpoints that are engaged in calls with the SBC. For local endpoints (that are on the same subnet as the SBC), this ping mechanism is used to keep the ARP cache refreshed in the SBC. If a local endpoint does not respond to the pings, and if media IP address is different than signaling IP address, the call may have audio issues.
Configuring the Media System
- In the WebUI, click the Settings tab.
In the left navigation pane, go to Media > Media System Configuration.
Media System Configuration
Port Range - Field Definitions
Number of Port Pairs
Music on Hold - Field Definitions
Music on Hold Source
Other Options - Field Definitions
Echo Canceller Type Option
Echo Cancel NLP Option
Send Stun Packets