NOTE: When the VOD Session Manager is a USRM, Cisco refers to this USRM as a VSM.
Here is an explanation of how the VOD Session Manager (VSM) initiates a release of VOD sessions that are older than 4 hours (configurable). The algorithm described below is similar to the releaseOldSessions script on the DNCS that many of our customers are familiar with. Both release VOD sessions that are older than 4 hours old. Also, the VSM has a retry and session audit mechanism built into its algorithm that is absent in the releaseOldSessions script on the DNCS. The main difference is that this functionality is built into the VSM, but the releaseOldSessions script must either be run manually on the DNCS or put into the DNCS crontab. The VSM will make the decision to release a VOD session base on age, typically configured for 4 hours, and then the VSM will send up to 3 teardown requests to the Edge Resource Manager (ERM). NOTE: Both the VSM and ERM are Linux servers running Cisco USRM software.
The “releaseOldSessions” algorithm is configured on the VSM in the Web UI under Applications.VodSm.Configuration as shown in the screen shot below:
Applications.VodSm.Configuration.SessionTimeout = 14,400 seconds (default, configurable)
ReleaseRetryCount = 3 (default, not configurable)
ALGORITHM: The VSM, being the VOD Session Manager, will send a session release request to the appropriate Edge Resource Manager (ERM) based on the configured “SessionTimeout”. By default this value is 14,400 seconds (4 hours, configurable). When the age of a VOD session reaches the SessionTimeout, the VSM will locate the appropriate ERM and send it a session release request for that session. If the ERM fails to acknowledge this release request, the VSM will retry the session release for the number of times configured in ReleaseRetryCount, which is 3. NOTE: Cisco Development has chosen a value of 3 for this parameter (the ReleaseRetryCount is not configurable). If after the 3rd release retry, the VSM still does not have an acknowledgement of session teardown from the ERM, the VSM will initiate a session audit of that ERM as a final attempt to tear down the session.