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So you want UC… what about your network?

When it comes to a Unified Communications (UC) solution, one of the things you may hear in your research is that UC will “bring your network to its knees” or that UC will necessitate an investment in large amounts of wide area network (WAN) bandwidth.  While certain UC modalities (video or application sharing) will take more bandwidth than others (instant messaging or voice) any decent enterprise UC solution can address bandwidth concerns through congestion management – prioritizing traffic when you need more bandwidth than is currently available – and congestion avoidance – mechanisms that try to avoid congestion in the first place.  Congestion management and avoidance mechanisms built-in to Microsoft Lync take the form of Quality of Service, Call Admission Control and policy sets complimented by a full suite of reports to validate or adjust these settings.
Quality of Service (QoS) configuration in Microsoft Lync is a fairly straightforward.  With a few PowerShell commands, Lync can be configured to mark network packets with Differentiated Services Code Point (DSCP) bits as well as to run specific modalities (Audio, Video, Application Sharing) within a set range of network ports.  Once these items are configured in Lync all that’s left is to have your routers and switches properly prioritize the workloads as appropriate within your network.
With Call Admission Control (CAC), Lync can be configured with specific bandwidth policies for Audio and Video calls.  CAC allows the Lync Administrator to configure thresholds for permitted bandwidth within a single call as well as permitted bandwidth for the aggregate of all calls.  CAC policies are typically created and assigned to bandwidth constrained links such as WAN connections between central and branch offices.  If a user tries to place a call and the bandwidth demands of the call exceed the set thresholds, CAC can be configured deny the call or redirect the call through an alternate connection.
Microsoft Lync has a full complement of policy settings that can be configured and applied to sites or users.  These policies allow for the control of items such as whether or not to allow video calls, desktop sharing or file sharing.  Video call policies can be further fine-tuned by configuring the maximum video resolution and maximum bandwidth allowed for a video call.
While configuring QoS, CAC, and policy settings is important to a successful, high quality UC experience, it is equally important to have good monitoring and reporting to validate the settings and to know what changes to make as conditions change.  The monitoring and reporting available in Microsoft Lync provides everything from the granular detail of a specific call to month over month call reporting statistics.
Proper planning and implementation of all of the tools outlined here: QoS settings, Call Admission Control and policy sets along with regular validation of settings through Lync monitoring reports will help you keep control of your network bandwidth as well as ensure a successful, high quality Microsoft Lync Unified Communications infrastructure.

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Scott Middlebrooks

I am a Senior Technical Architect within the Microsoft practice at Perficient. In this role, I am responsible for strategy, delivery, operations, and technical sales support aspects of enterprise infrastructure projects, especially Microsoft Unified Communications projects. I have extensive experience in traditional telephony, voice over IP, network design and architecture, systems engineering and infrastructure security. Prior to joining Perficient, I served as the Chief Information Officer at Northridge. Northridge was a leading Microsoft consultancy based in Atlanta, Georgia and was acquired by Perficient in July of 2012. I posses several Microsoft Certifications including: Microsoft Certified Systems Engineer (MCSE) on both the Windows NT 4.0 platform as well as the Windows Server 2003 platform, Microsoft Certified Technology Professional for Lync and Microsoft Certified Technology Specialist for Virtualization. I hold a Bachelor of Business Administration degree in Management Information Systems from the University of Georgia, GO DAWGS! In my time away from the office I enjoy time with my family and friends, UGA football, anything aviation related and I love cooking, especially on my Big Green Egg!

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