Entering Survivable Mode

Registration Behavior

When the Oracle® Enterprise Session Border Controller enters Survivable Mode, it performs as follows for registrations:

For endpoints already Registered...	For new Registration requests... (either new endpoints or endpoints whose registration expires when in Survivable Mode)
the Oracle® Enterprise Session Border Controller acts as the registrar of the local SIP phones by providing 200 OK responses to subsequent REGISTER refresh messages from endpoints in the Oracle® Enterprise Session Border Controller’s reg-cache for the duration of Survivable mode. This presumes that "registration-caching" has been enabled in the Oracle® Enterprise Session Border Controller onfiguration.	the Oracle® Enterprise Session Border Controller allows the new Registrations to be successful (without providing Authentication), incorporating them into the Oracle® Enterprise Session Border Controller registration cache.
the Oracle® Enterprise Session Border Controller lowers the "reg-expires" value to 30 seconds by default for all Registration Requests between the endpoints and the Oracle® Enterprise Session Border Controller.	the Oracle® Enterprise Session Border Controller lowers the "reg-expires" value to 30 seconds by default for all Registration Requests between the endpoints and the Oracle® Enterprise Session Border Controller.

In Survivable Mode, the Oracle® Enterprise Session Border Controller routes incoming INVITEs based on the lookup from the registration cache. If the entry is part of the registration cache, the INVITEs are routed depending on the contact information from the cache. If the entry is not part of the registration cache, local policy is used if there is any local policy configured on the Oracle® Enterprise Session Border Controller. The prefix length in the Survivability configuration is taken into consideration when creating the extension for the phone number in the registration cache.

Call Processing Behavior

After the Oracle® Enterprise Session Border Controller enters Survivable Mode, it performs as follows for call processing:

• Allows incoming sessions (either from an endpoint or an external PSTN gateway or alternate trunk) to be processed locally, based on its Registration cache.
• Locally handles multiple identities based on the registered P-Preferred-Identity (or via BroadSoft’s proprietary mechanism).
• For session requests coming from local endpoint destined to non-local destinations, it routes to alternate PSTN gateways or SIP trunks, if configured.
• It performs registration cache (reg-cache) matching based on substrings of the received dialed digits (for example, a phone registers as sip:[e-mail] and a local user dials sip:[e-mail]).

  Note:

  The Oracle® Enterprise Session Border Controller allows extensions to be dialed based on it's multiple user identities (identified either by using P-Asserted-Identity or BroadSoft's proprietary mechanism.) For more information about Survivability when using the BroadSoft server, see Remote Site Survivability with a BroadSoft Server