In/Out direction flags

Last Updated : Mar 08, 2017 |

The In/Out direction flags are available for each media type and refer to the direction of the media stream that the Application Rule processes if checked or enabled.

For an Inbound Call with SDP to the Avaya SBC, Application Policy Enforcer checks if the Inward direction flag is enabled for all the media streams received in the SDP. For an Outbound Call with SDP from the Avaya SBC, Application Policy Enforcer checks if the Outbound direction flag is enabled for all the media streams received in the SDP. If at least one of the required In or Out flags is disabled, the Application Policy Enforcer rejects the call with a SIP error response. An Incidence/Syslog is raised with the appropriate cause for administrative reasons.

The Avaya SBC does not release a call immediately after receiving a SIP BYE from the network. The software internally holds the call state for 32 seconds before releasing the call completely. This hold time is required for internal Avaya SBC call resource management and SIP Protocol procedures.

So the counters Maximum concurrent sessions per endpoint / policy must be configured by accounting for the call hold time and the additional 32 seconds of hold time.

Max Concurrent Sessions Per endpoint = (Number of Calls per second) * (Call Hold Time in seconds + 32)

For example, if an endpoint makes 2 calls every 1 second with a call duration of 60 seconds, the maximum concurrent sessions for each endpoint can be 2*(60 + 32)=184.

  1. The system runs the Application Policy Enforcer twice during Inbound / Outbound Policy Invocation while processing a call.

    If the same endpoint policy group is run twice, the counters Maximum concurrent sessions per endpoint / policy are increased twice. This process might cause a Policy violation if not provisioned correctly.

    So use separate Endpoint Policy Groups for Subscriber and Server Flows.

    Note:

    Also note that in case of a call from a Remote User to Remote User, four Policy Invocations are performed as there are two separate SIP Dialogs involved in a call. This process is the general case where the Call Server acts as a B2B UA.