Survivable Branch Servers and Appliances

If an organization is already placing a Mediation Server and media gateway in the branch office, a more robust solution is to deploy a Survivable Branch Server or a Survivable Branch Appliance in the office. These solutions provide the same benefits as a local Mediation Server, but also provide local registrar services in the branch. So when the WAN is unavailable, users in the branch stay connected to the survivable branch component and can still make and receive basic phone calls, as shown in Figure 32.5.

Figure 32.5. WAN outage with a Survivable Branch Server.

User accounts are homed to the survivable branch component, but still receive the majority of services from an associated Front End pool in a central site. The survivable branch component is designated as the primary registrar for the users so that when they sign in, they register to a local server.

However, all conferencing and web services exist only on a Front End pool and are still always accessed across a WAN link to the pool associated with the branch site. The survivable branch component is typically paired with a local media gateway to provide branch users with a local route to the PSTN for inbound and outbound calls.