Survivable Branch Appliances

In Lync Server, third-party media gateway vendors will be producing devices called Survivable Branch Appliances (SBAs), which give a remote site’s basic telephony features in the event of a WAN outage. Previously, when a remote site lost a WAN link, it caused users in that site to become disconnected from Communicator and unable to make phone calls. Now, the SBA can be connected to the PSTN and in the event of a WAN outage, users remain connected and are able to make and receive phone calls.

SBAs are first configured by administrators at the main site and then shipped to a branch office where they can be powered on and running with a few basic steps. The SBAs come in the form of stand-alone appliances or modules for switching equipment already located at a branch. Figure 17.18 shows a sample topology where an SBA exists in a branch office with its own PSTN connection.

Figure 17.18 Survivable Branch Appliance