Specifications

14 Reference Architecture | Dell
TM
Unified Communication Solution with Microsoft® Lync® Server 2013 for Single Site
Implementation | Version 1.0
3.2 Lync Server 2013 Core Architecture
When deploying a Lync solution, the first step is to articulate a design that will address the communication
requirements across the enterprise. The following section provides the design framework adequate for
1,000 Lync users with instant messaging, audio/video, web conferencing and Enterprise Voice
communication modalities.
The primary component of this architecture is a paired Lync Server 2013 Standard Edition server pool that
serves these different modalities. The Standard Edition pool consists of two Standard Edition servers that are
identical and provide communication services for a group of users. This pool of identically configured
servers provides scalability as well as availability in the event of a server failure. The Standard Edition server is
also the primary store for the user and conference data, where each user’s data is replicated to another
Standard Edition server. The Lync Standard Edition server that acts as the primary registrar hosts an SQL
Express instance to store the databases, and these databases are synchronized with the databases on
another Standard Edition server for Lync, which acts as the backup registrar. The databases are important to
show the presence information and to continue other user activities.
In addition, an SQL Server virtual machine is deployed to host the Archiving+Monitoring and Persistent Chat
server databases.
Figure 2 provides a high-level schematic of a Lync Server 2013 core architecture that has been sized for
1,000 users. The architecture has been built on the design principles discussed in Section 3.1.
High Availability
• Application-level high availability. The Microsoft Lync Server 2013 core architecture uses paired
Standard Edition servers and two Office Web Apps servers (OWS). By ensuring that there are two
instances of the server roles, there is no single point of failure at the application level and thus
service downtime to the end user is minimized.
•
Infrastructure high availability. This is provided by having the VMs hosted on multiple physical
Hyper-V hosts and by having the hosts connected to redundant network switches. Further, the
placement of these VMs is arranged to ensure that no VMs with identical server roles are on the
same physical Hyper-V host. Note that the Hyper-V hosts are not part of a virtualized cluster and
the VMs do not fail over or live migrate across Hyper-V hosts. Lync service availability is provided
by having paired the pool of Lync applications, which is a native high availability feature.
Resource Consolidation
• Leveraging virtualization. By virtualizing the Lync Server roles on top of Windows Server® 2012
Hyper-V hosts, dedicated hardware for each role is no longer necessary. For example, in the
reference architecture, one of the Dell™ PowerEdge™ R620 hosts consolidates Lync Standard
Edition, Office Web Apps (OWS) and a Lync Persistent Chat role on a single server.
• Service consolidation. By deploying the Mediation Server, Archiving and Monitoring roles
collocated with the Standard Edition server, management complexities are reduced without any