CANC is an autonomous message transmitted by the network element (NE) to a user when a session established by that user is terminated because no messages were exchanged for a long period of time and the session times out. There is a default timeout period based on the user’s privilege/security level. Timeouts can be provisioned through Cisco Transport Controller (CTC). Timeouts can be provisioned with the SET-ATTR-SECUDFLT command. The default timeouts based on privilege/security level are:
The Superuser (SUPER) has a timeout period of 15 minutes.
The Provisioning user (PROV) has a timeout period of 30 minutes.
The Maintenance (MAINT) user has the timeout period of 60 minutes.
The Retrieve user (RTRV) has no timeout.
When a timeout occurs, the corresponding port drops the session and the next session initiation at that port requires the regular login procedure.
The CANC message is only used to indicate that a session has been terminated because of a timeout. If a session is terminated for a different reason (for example, forced logout or loss of communication), the REPT EVT SESSION message is used.