A Call Admission Profile provides SIP level call admission control by regulating call attempts per second, and the rate of new invite/non-invite sessions. Once the SBC limits are met, SIP will no longer accept/issue new invite or non-invite sessions (except 911 calls). This feature protects the SBC from overload conditions (an overload condition is detected if the average rate of invite and non-invite sessions exceeds the pre-determined limit or the CPU threshold is exceeded). It also prevents internal/external DOS attacks in an otherwise normal network using overload detection and resource leaks/malfunction detection.
When rejecting calls or sessions on account of admission-control, SBC sends "480 Temporarily Unavailable" response to the peers.
This functionality applies to SIP calls only.
Managing Call Admission Control
- In the WebUI, click the Settings tab.
- In the left navigation pane, go to SIP> Call Admission Control Profile. The Call Admission Control Profile window is displayed.
- From the Admin State drop down box, select Enable (default; enables Call Control feature) or Disable (disables Call Control feature).
- Click Apply.