ONF envisioning a more wireless-friendly OpenFlow

Tammy Parker, FierceWirelessTech

The Open Networking Foundation's newest working group is taking an evolutionary approach to bringing software-defined networking (SDN) to the wireless and mobile network domains, but the results of its efforts may nonetheless be revolutionary.

The ONF's new Wireless and Mobile Working Group is starting out by looking at three primary areas where SDN could dramatically affect operations. These are the wireless transport network, or backhaul; 3GPP-defined mobile packet core; and enterprise applications that unify and control fixed and wireless operations. Serge Manning, the group's head, said an example of that last one is wireless in the form of Wi-Fi integrated with fixed in the form of Ethernet.

What is notable about the group's initial remit is that it could have been much more extensive, but as Dan Pitt, ONF executive director explained, the idea wasn't to "boil the ocean."

He said the ONF began studying the idea of SDN for wireless and mobile in late 2012, and efforts quickly transitioned to a discussion group. A charter application was subsequently prepared for the ONF board outlining potential use cases.

"We normally send a charter application to the board of about five pages," he said. This time, however, it was about 10 pages, which was actually shortened from 55 pages because participants had articulated 17 different use cases. That reflects the phenomenal interest in the working group's mission.

Manning, whose day job is being Huawei's senior manager for corporate standards, said the working group got a bit of a jump start because the discussion group did so much work on the use cases that they basically finished and soon will be posted on the ONF website. The working group is now moving on to addressing the architecture and protocol set.

OpenFlow can already be applied in wireless networks, but there is a need for protocol extensions, new parameters "and slightly different ways of doing things that will bring more value to the wireless networks," Manning said.

He stressed that the group's approach revolves around maintaining the 3GPP control and signaling that already exists in the cellular system in order to enable operators to start using SDN and the OpenFlow protocol without having to do away with their legacy systems, which run the gamut from billing systems, back-ends, policy engines, etc.

"If you look at the gateways within an LTE evolved packet core, for example, there are monolithic gateways. There's a control plane in the gateway and also a data plane," Manning said. He explained that the new working group envisions separating those control and data planes and pushing them out to the edge or using them in different ways "to make them more flexible and adaptable for the wireless network."

Manning acknowledged that down the road SDN and related virtualization efforts may very well impact actual network blueprints, but any changes will not come overnight. The working group is being careful to ensure that its proposals make good business sense and will benefit mobile and wireless operators with their current use cases, he added.

Since October, the ONF has had a working group exploring the northbound interface between SDN controllers and automation systems and orchestration software. But OpenFlow is a southbound protocol, enabling direct access to, and manipulation of, the data plane (also called the forwarding plane) of network devices, such as switches and routers.

SDN can make use of other protocols rather than OpenFlow, and more than a few pundits contend that OpenFlow is "just another protocol" in a jungle of protocols, something that riles both Manning and Pitt. "If you look at the Internet protocol it certainly has changed the world. So [its impact] depends on what the protocol is, and what it allows you to do," said Manning.

Added Pitt: "Yes, OpenFlow is a protocol and there are lots of them out there, but it is sort of the antidote to the bucket of protocols we have now in networking, including mobile and wireless and beyond."

ONF wants to make OpenFlow suitable for many different environments, so people can innovate above and below it. "What we don't want to see is a plethora of single-purpose protocols on the southbound side of SDN, and that's why we started this working group," Pitt said. --Tammy