Surrogate Agent Refresh on Invalidate
Surrogate agent registrations normally only re-register when nearing their expiration time. When a registrar fails, the surrogate agent will wait until the expiration time to refresh the registration with an in-service registrar.
You can configure your Oracle® Enterprise Session Border Controller to immediately refresh the surrogate agent registrar with an in-service registrar by enabling the existing parameter invalidate-registrations.
Invalidate Registrations
An existing feature called invalidate-registrations located in the session agent keeps track of when surrogate agents go out of service. When REGISTER messages are received, registration entries that had out-of-service session agents since the last REGISTER will always allow the message through to the registrar (as opposed to responding directly from the cache).
The invalidate-registrations parameter in session agent configuration enables the Oracle® Enterprise Session Border Controller to detect failed Registrar session agents.
If invalidate-registrations is enabled for the session agent, a response from a surrogate REGISTER that contains a service-route header that corresponds to a session-agent is installed to the registration cache entry.
The surrogate-agents are scanned. Surrogate agents with registration entries matching the out-of-service registrar have their timer reset to initiate a refresh. For an immediate refresh, the registration entry will only be considered when the service-route session agent goes out-of-service. The service-route session agent takes precedence and any previous registrar session agent w ill not be considered for an immediate refresh of the surrogate-agent registration.
