In the dual registration model, the phones are configured with the Lotus Sametime Unified Telephony as their Primary SIP Server/SIP Registrar and a secondary SIP Server as their backup SIP Server. In this case, the communication layer of the phone will send registration requests directly to the Lotus Sametime Unified Telephony and to the backup SIP Server (RG8700 v1.2). The backup SIP Server offers a similarly limited set of SIP Server capabilities.
When compared to the proxy registration model, the dual registration model has some disadvantages:
Phones have to register with both the Lotus Sametime Unified Telephony and the Survivable Media Gateway.
When detecting survivaibility mode, the media gateway takes no further action. Thus phones have to detect the outage themselves.
Also when detecting a restoration of normal mode, the media gateway takes no further action. Thus phones have to wait, until they registered themselves successfully again.
As an advantage, dual registered phones are not effected by an outage of the proxy itself.
Parent topic: Survivability Overview