Branch Site Topologies and Components

Either through organic growth or through acquisitions, many organizations have multiple offices, often called branch offices, in different geographic locations. This creates a challenge for the IT department to service such remote offices. Often it’s not cost effective to deploy a Standard Edition server or Front End pool and hire a full-time IT administrator for each branch office. This leaves remote management as the most cost effective way to administer IT in these remote offices.

Another problem that often occurs when remote offices are connected to the central office or headquarters over a WAN link is network connection failures to the central office. In such circumstances, employees in these remote offices must be able to continue working. This is particularly important when it comes to mission-critical services such as voice service and connectivity between users within the remote office.

To address these two concerns, Lync Server 2010, through Microsoft Certified Partners, provides appliances that are specifically designed to be deployed in remote offices. These Survivable Branch Appliances, as the name indicates, provide a back-up when connectivity to the Lync Servers in the central office is severed. When users are no longer able to connect to their pool in the central office, Lync 2010 automatically signs-in to the backup home server, the Survivable Branch Appliance that is deployed in the branch office, and continues to provide the same service with some limitations.

The Survivable Branch Appliance runs the Windows Server 2008 R2 operating system with the Lync Server Registrar service and Mediation Server, and is integrated with a media gateway to provide connectivity to the PSTN. Because the location of the Survivable Branch Appliance may not have IT personnel, the appliance is designed for easy deployment and remote management. Before a Survivable Branch Appliance is deployed, administrators can set up its account and configuration at the central office. A technician at the branch site then begins the deployment, and the deployment can be completed by the branch site technician or by administrators at the central site.

If the WAN connection between a branch site and its central site fails, the Survivable Branch Appliance provides the following voice features to users at the branch site:

  • All two-party functionality, including instant messaging and audio/video conferencing
  • PSTN inbound and outbound calls
  • Intrasite and intersite calls
  • Call hold, retrieve, and transfer
  • User authentication and authorization
  • Leaving and retrieving voicemail
  • Call forwarding, simultaneous ringing, call delegation, and team calling
  • Call detail recording (CDR).
  • PSTN dial-in conferencing with Conferencing Auto-Attendant

Users in the branch office when connected to the Survivable Branch Appliance can place calls to the PSTN via the Survivable Branch Appliance integrated gateway. This failover solution allows branch office users to continue doing business as usual as well as place emergency calls in the event of a natural disaster.