This entry contains data describing a subscriber sessions, including its state, configuration, and collected identities. An entry exists for a corresponding entry in the ifTable describing a subscriber session. Currently, subscriber sessions must have one of the following ifType values: 'ppp' 'ipSubscriberSession' 'l2SubscriberSession' The system creates an entry when it establishes a subscriber session. Likewise, the system destroys an entry when it terminates the corresponding subscriber session.