Specifications

20 Reference Architecture | Dell
TM
Unified Communication Solution with Microsoft® Lync® Server 2013 for Single Site
Implementation | Version 1.0
for conferencing, the Front End VM may need to periodically request increased memory from the
hypervisor instead of being guaranteed resources.
• Use fixed disks instead of dynamic disks. The use of fixed disks (or pass-through disks) guarantees best
performance and is recommended for production environments.
• Microsoft recommends that physical CPUs not be oversubscribed by the VMs residing on the host. For
example, if the number of cores available is 16 and the number of vCPUs allocated is 24, this indicates
over-subscription since the Virtual CPUs (vCPU) : Processor Cores ratio is more than 1:1. Over-
subscribing the CPUs will cause contention for resources. Since Lync works with delay-sensitive voice
and video traffic, there could be adverse effects due to over-subscription, and it is not recommended
at this time.
• The use of “Synthetic network adapter” is preferred over “legacy network adapter” in Hyper-V and
offers better performance.
3.3 Lync Server 2013 Edge Architecture
The highlighted section of Figure 4 shows the Lync components that need to reside in the perimeter
network with internal and external firewalls. This reference architecture assumes that an existing perimeter
network already exists and does not explicitly provide details for firewalls. Dell SonicWall
has a wide range
of products to fulfill any needs for security or firewall devices.
In order to follow the high availability design principle, the proposed Edge architecture consists of an Edge
pool with two Edge Server VMs and uses DNS load balancing on both the internal and external Edge
interfaces. An HTTPS Reverse Proxy can also be configured and is required to support the sharing of web
content and web services to federated and external users and for enabling certain features as detailed on
the Microsoft Setting Up Reverse Proxy Servers
site. Since Reverse Proxy cannot be collocated with the
Edge Server, two additional VMs would be needed if a Reverse Proxy Server is required. To see a list of
Reverse Proxies qualified with Microsoft Lync Server 2013, visit the
Infrastructure qualified for Microsoft
Lync site.
Both the Edge and Reverse Proxy Servers are consolidated as VMs on two Dell™ PowerEdge™ R420 1U
servers, each with dual-socket Intel® Xeon® E5-2400 series processors, 32 GB of DDR3 RAM and support
for up to 8 x 2.5-inch internal HDDs. Each of these servers is running Windows Server 2012 with Hyper-V.
The detailed hardware specifications for these servers are provided in Section 4.