Enhanced Voice Resiliency in Central Sites and Branch Offices
Topic Last Modified: 2011-03-18
In Microsoft Lync Server 2010, enhanced client registration, discovery, and routing improve service resiliency and flexibility in the design and deployment of your Enterprise Voice solution.
The Registrar authenticates users and provides routing services. The Registrar is not a stand-alone server role but is installed on Standard Edition servers, Front End Servers, and Survivable Branch Appliances.
Each user is assigned to a particular Front End pool, which becomes that user’s primary Registrar pool. Each pool can have a designated secondary Registrar pool, which is used in if the primary pool fails.
Central Site Resiliency
If a user’s primary and secondary Registrar pools are at different central sites that are connected by a resilient WAN link, if the primary pool fails, the user can be immediately transferred to the secondary pool. The first sign-in server—typically a Director—will always direct the user’s client to either the primary pool or, in the event of failover, to the secondary pool.
If clients connect to the secondary Registrar pool, the following voice features will be available:
All two-party functionality, including instant messaging and audio/video calls
Outbound PSTN calls
Inbound PSTN calls, if the carrier provides the ability to failover to a secondary central site
Enterprise calls both within a site and between sites
Basic call handling, including call hold, retrieval, and transfer
Advanced call handling, depending on user’s call-forwarding settings, including call forwarding, simultaneous ringing of endpoints, and call delegation features
Call detail recording (CDR)
Location Information service for emergency calls
Branch Site Resiliency
For smaller branch sites without on-site IT administrators, a Survivable Branch Appliance (that is, a "branch in a box" that is easy to deploy, configure, and remotely manage) can provide basic voice services to users in the branch site during a WAN outage.
The Survivable Branch Appliance is a combination of a server (often a blade server) and a PSTN gateway. It is designed for branch sites that do not have a Lync Server 2010 Front End pool or Standard Edition server. The Survivable Branch Appliance can provide basic phone services to users at the branch site when the WAN link to the Lync Server central site is down.
The blade server of the Survivable Branch Appliance runs the Windows Server 2008 R2 operating system and the Lync Server Registrar service and Mediation Server. 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 site. 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 (A/V) calls
PSTN inbound and outbound calls
Intrasite and intersite calls
Call hold, retrieve, and transfer
User authentication and authorization
Leaving and retrieving voice mail
Call forwarding, simultaneous ringing, call delegation, and team calling
Call detail recording (CDR).
PSTN dial-in conferencing with Conferencing Auto-Attendant