SDN & UC Integration: A Work In Progress

As organizations tackle software-defined networking and figure out ways the technology can help them, one use case emerged early on: helping overcome unified communications performance issues. Microsoft led the charge on this front with its Lync SDN API.

Several SDN vendors, including HP, have demonstrated integration with the SDN API for Lync (now called Skype for Business). And WiFi vendors such as Aruba Networks have branched out into SDN via the Lync API. Some experts, including Tom Hollingsworth, a Network Computing contributor, have called the Lync the "killer app" for SDN.

Terry Slattery, principal engineer at network consulting firm NetCraftsmen, sees great potential for communications and SDN integration, but said there's still work to be done. He'll delve into the topic in his Using SDN APIs for Communications presentation at Interop Las Vegas next week.

The Lync SDI API allows the application to tell the network a call is coming up between two endpoints so that the network to customize itself to handle the call, Slattery said in an interview. What's missing, though, is the ability for the network to be able to tell the application to make adjustments if, say, a link has gone down or a new link has come up. For example, if a link has been added, a telepresence or videoconferencing system could go from standard definition to high definition.

"It can go both ways," he said. "That integration is going to be really powerful."

Slattery expects to see more UC applications follow Microsoft's lead by integrating with SDN controllers. Cisco, for example, is developing an SDN interface for its UC technology, a spokeswoman confirmed.

What's happening with the Lync SDN API isn't an application speaking directly with the SDN controller, but rather there's an intermediate system -- sort of like middleware -- that acts as an interface between the application and network, Slattery said. In the future, that middleware potentially could handle different UC systems (crucial if an organization has gone through a lot of M&As) and eventually other applications that need priority treatment. For example, a healthcare organization may want to prioritize a bedside monitor over a voice call.

The International Multimedia Telecommunications Consortium, a nonprofit industry association, sees SDN as a way to address UC performance issues. Last fall, the group released a whitepaper that describes the shortcomings of traditional QoS systems in UC and collaboration deployments, and an automated "quality of experience" service module using SDN to dynamically adjust the network to UC requirements.

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"A comprehensive approach to delivering an optimal QoE for UC&C environments requires new mechanisms like those defined in the IMTC’s specification, thereby allowing UC&C applications to signal multimedia application requirements to the network via an application programing interface (API)," the association said in announcing the whitepaper. "These mechanisms enable automated QoE services to optimize end user quality, including dynamic QoS marking, dynamic traffic engineering and admission control."

Slattery sees the implementation of SDN -- overall, not just with UC -- leading to a merger of network and IT teams. That will require both new skills and a culture change.

"Networking teams will have to get smarter about what software is about. I don't know if they necessarily need to become programmers, but they need to understand some of the terminology and have to be able to communicate more clearly with the IT team," he said. "And vice versa, the IT team will have to become smarter about networking -- what's reasonable and not reasonable."