SIP Session Timer Feature

SIP does not have a keepalive mechanism for established sessions and it does not have the capability of determining whether a session is still active. User agents (UAs) may be able to determine whether a session has timed out by using session specific mechanisms, but proxies cannot always determine when sessions are still active.

The Oracle® Enterprise Session Border Controller provides a SIP session timer feature that, when enabled, forwards the re-INVITE or UPDATE requests from a User Agent Client (UAC) to a User Agent Server (UAS) in order to determine whether or not a session is still active. This refresh feature works for both UAs and proxies. The following paragraphs provide additional information about the session timers on the Oracle® Enterprise Session Border Controller.