At Microsoft, Software-Defined Networking Takes Cloudy Turn

By Pedro Hernandez  |  Posted 2015-08-20 Print this article Print
Microsoft SDN

Microsoft details its efforts to help mainstream software-defined networking, a pillar of the company's own hyperscale cloud capabilities.

Microsoft is bullish on software-defined networking (SDN) if for no other reason than the technology's ability to help it provide Azure cloud services to millions of users.

The Redmond, Wash-IT giant is presenting at the ACM SIGCOMM 2015 (Association for Computing Machinery's Special Interest Group on Data Communications) conference, currently taking place in London. There, the company is offering attendees a glimpse at how SDN is enabling cloud-based workloads at a scale that would otherwise grind to a halt under legacy network architectures.

Microsoft is banking on SDN technologies not only to grow its own cloud computing capabilities, but also to meet the needs of enterprise customers and data center operators seeking more flexible, application-aware ways of managing their networks. The latest preview version of Windows Server 2016, released yesterday, offers new SDN capacities, including a scalable network controller and a new software load balancer.

Back at Microsoft's own IT facilities, the company has fully embraced SDN as a pivotal component of the company's software-defined data center vision.

"Given the scale we had to build to, and the need to create software-defined data centers, for millions of customers, we had to change everything in networking, and so we did—from optical to server to NIC [network interface card] to data center networks to WAN [wide area network] to Edge/CDN [content delivery network] to last mile," wrote Albert Greenberg, a distinguished engineer in Microsoft's Networking Development unit, in a company blog post.

One area of focus for the company is the open Switch Abstraction Interface (SAI) specification, championed by Microsoft, Dell, Big Switch Networks and Mellanox.

"The SAI is the first open-standard C API for programming network switching ASICs. With ASICs, vendors are innovating ferociously fast the formerly strict coupling of switch hardware to protocol stack software [that] prevented us from choosing the best combination of hardware and software to build networks, because we couldn't port our software fast enough," Greenberg explained. Microsoft is demoing Azure Cloud Switch, switching software that runs atop SAI, at SIGCOMM.

In managing its large-scale Clos networks—a topology also used by Google in which smaller, commodity switches are configured in a way that delivers the capabilities of a larger logical switch—Microsoft relies on technologies like PingMesh and EverFlow to ensure the availability of its data services. "At cloud scale, component failures will happen, and Azure is fine with that as we scale out to numerous components. Our systems detect, pinpoint, isolate and route around the faulty components," Greenberg said.

Despite the flexibility provided by a software-based approach, it can fall short, admitted Greenberg. When that happens, the company turns to Azure SmartNIC technology.

SmartNIC employs "Field Programmable Gate Arrays (FPGAs), which enable reconfigurable network hardware," he said. "No one knows what SDN capabilities will be needed a year from now. Our FPGA-based SmartNIC allows us to reprogram the hardware to meet new needs, as they appear—reprogramming, not redeploying hardware."


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