Reducing NOTIFY Traffic
RFC 3265 stipulates that the Subscription server sends NOTIFY messages to all subscribers when a UA sends a registration refresh. This can generate excessive NOTIFY traffic. You, however, can mitigate this by configuring the Oracle Communications Core Session Manager to limit notification traffic. By specifying the number of seconds between NOTIFY messages, you prevent the Oracle Communications Core Session Manager from sending notifications upon events that do not generate a change in the registration database.
Database changes that trigger notifications when this option is configured include:
- The Cseq number of the REGISTER message increases by more than 1
- The call-ID changes
- A contact parameter changes
- The number of contacts changes
Upon expiry of this timer, the Oracle Communications Core Session Manager sends out a NOTIFY for every registration event subscription. Note also that the Oracle Communications Core Session Manager does not send the cseq attribute in the CONTACT element when this interval is configured.