The system uses the Server Flow PSTN-Trunk to determine the Endpoint Policy Group configuration PSTN-default-low. The routing system applies all the endpoint policy group configurations on the incoming SIP INVITE request before proceeding with Route Resolution.

Application Rules for the endpoint policy group PSTN-default-low are enforced by the Application Policy Enforcer on the incoming SIP INVITE request. The counters Maximum sessions per endpoint/policy are increased by one for the profile PSTN-default-low. The counters are decreased after the call is released.

If this is the first call received by Avaya SBC from the PSTN trunk, the value of the counters will be 1.