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How an SDN API could improve Microsoft Lync performance

With a new Microsoft Lync SDN API, network managers can correlate unified communications performance with what's happening on the routed network.

Microsoft will use an SDN application programming interface (API) to address a critical weak spot in its Lync unified communications solution -- a lack of integration with the underlying network.

In December, the company released a Lync SDN API that gives users clear visibility into the characteristics, health and metrics of each voice, video and data media stream in the Lync environment, as well as information about user, location and device.

Before you had the Lync SDN API, you had network health metrics and you had call quality metrics from Lync, but you didn't have an easy way to correlate them.

Robert Fenstermacher,
director of product and marketing solutions, Aruba Networks

Because all media streams in Lync are encrypted, it was previously impossible for network engineers to see whether sessions were made up of voice, video or data, or to pin the root of application performance problems to issues in the underlying network.

"Before you had the Lync SDN API, you had network health metrics and you had call quality metrics from Lync, but you didn't have an easy way to correlate them," said Robert Fenstermacher, director of product and marketing solutions at wireless networking vendor Aruba Networks. For wireless network managers, this was especially problematic because Wi-Fi users tend to roam, in addition to switching between communications types during the course of one session.

Meanwhile, similar problems arose on wired networks, where traditional network monitoring and deep packet inspection tools didn't work due to encryption, explained Tom Tuttle, vice president of Nectar Services, a network monitoring and management tool provider. In a Cisco or Avaya UC environment, Nectar tools essentially act as another router in the network, gaining knowledge of all of the interfaces and routing tables and correlating this to application performance.

"Microsoft knew there were issues taking place in the client routed network that were impacting Lync," Tuttle said. "If you are going to play in the big leagues, you need diagnostic capability."

With the Lync SDN API, users can connect to a front-end server in the Lync environment that is responsible for initiating every single media stream. That server will provide ongoing information about each stream, user and device. A number of companies, including Aruba, Nectar and HP Networking are already using the API. In Aruba's case, the server will feed data directly into the centralized Wi-Fi network controller, which can rely on the information for network optimization, such as load balancing. There will also be a shared diagnostic and management dashboard integrating Lync and Aruba performance information, Fenstermacher said.

For Nectar the information will be fed directly into monitoring tools.

"Now we can see that a certain router has Lync pre-set for 10% of traffic, but that the router is pushing over 25%, for example. We know this instantly," Tuttle said.

While many users still don't totally understand SDN, explaining the role of an SDN API in UC won't be a huge challenge, said Michael Cassady, director of operations at The Via Group, a systems integrator that sells both HP Networking and Lync technology. The company has spent plenty of time tackling quality of service (QoS), jitter and latency issues in Lync 2013, so customers understand the need for network analysis and assessment, he explained.

Lync SDN API will become more crucial in changing network architecture

While the Lync SDN API can immediately enhance diagnostics and QoS in a legacy network, it will have bigger benefits as SDN architecture is implemented in the enterprise network.

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Cisco vs. Lync: Comparing the features

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Are Lync's collaboration tools ready for business?

Polycom and Microsoft Lync for better video

Will the Skype-Lync integration spark UC federation?

In a total SDN architecture, Lync will be able to demand more network capacity or varying levels of QoS in real time, and networks can automatically respond. Essentially, Microsoft is capitalizing on one of the more radical concepts in SDN -- that applications should be able to directly demand resources from automated underlying networks for improved performance.

"In any UC implementation, there are dozens of network elements -- from routers to reverse proxies, intrusion detection systems to application delivery controllers, firewalls to session border controllers -- that all need to be provisioned and configured correctly for optimal media flow," wrote Senior Product Marketing manager Jamie Stark on the Lync blog. "Instead of having all of these elements configured discretely, SDN provides a model for a single policy-based method of operations, where the application tells the network what needs to happen."

New SDN networks will mirror Wi-Fi architectures such as Aruba's that have a centralized controller, which directs flows between nodes on a distributed network. In SDN, that centralized controller will not only direct packet flows, but will play a role enabling automated provisioning of virtual network segments and the policies that guides them.

In the Lync scenario, the front-end server will speak directly to these SDN controllers, which in turn will make network provisioning and policy changes to support the application automatically. HP networking, which has OpenFlow switches and an SDN controller, is already demonstrating this with the Lync SDN API.

This week at the Lync conference in Las Vegas, Microsoft is expected to further detail plans for Lync in the SDN environment.

Let us know what you think about the story; email Rivka Gewirtz Little, executive editor, or follow her on Twitter @RivkaLittle.

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I'd be happy if Microsoft simply fixed Lync 2011 for Mac and made a reliable client for Mac users.