Cisco On Board with SDN, OpenFlow

Networking giant Cisco Systems has remained an industry leader by understanding and leading industry transitions. One such transition occurring is the emergence of software defined networking (SDN) and the OpenFlow protocol and it’s a transition that Cisco doesn’t plan to miss.

SDN, OpenFlow embraced with open arms

While some have speculated that SDN is a risk to Cisco and its networking business, nothing could be further from the truth. The truth is that today, Cisco executive, David Ward is the chair of the Technical Advisory Group (TAG) at the Open Networking Foundation (ONF), helping to build SDN. In an interview with EnterpriseNetworkingPlanet, Ward detailed his views on what’s right and what’s wrong with SDN and OpenFlow, as well as providing insight into what Cisco is doing today.


At Cisco, Ward is the CTO and chief architect of the Service Provider Division and as such is directly involved with Cisco’s technical efforts. His role at ONF is about helping to ensure the effort moves towards a real standards body. In terms of Cisco’s view of SDN in general terms, it’s an area of active interest and activity, today.

“The machine is turned on,” Ward said. “What I mean is that Cisco is embracing and has been embracing the concepts of software defined networking for quite a while now. We haven’t gone public because we’ve been doing the research side for R&D.”

Ward even hinted that carriers are using Cisco networking equipment for SDN deployments already.

Cisco’s vision of SDN is a broad one due to the breadth of Cisco’s vast networking portfolio. In fact, as reported in eWeek today, the company is “spinning-in” a company called Insieme to develop products around SDN.

“You can use programmability to harvest information and program state into the network at so many different points in the network, we don’t want to see SDN limited to just a multi-tenant data center,” Ward said. “We’re embracing SDN and we’re trying to push it into different parts of the network where we have visibility and where customers want to use this type of technology.”

To date, big networking vendors like HP and Juniper have officially supported OpenFlow and SDN on their switches. To fully program a network also requires a controller layer, which is where companies like startup Big Switch now play. Cisco could well be active in both of those layers.

“We have already invested and acquired a number of orchestration vendors,” Ward said. “What we see from a controller point of view, is that there won’t just be one controller doing all services and aspects of network, it’s just not the way the network is built today.”

Today, on the ASR 9000 router for example, Cisco already has an SDN model that is enabled for customers. Devices can be programmed such that the ASR 9000 is the controller for a programmable network. Overall, Ward stressed that it is challenging to see how all the different network elements might come together for unified SDN orchestration.

“As we evolve network architectures, we may see a unification of orchestration elements or they may continue to be different items where one is fired up for each distinct service,” Ward said.

OpenFlow protocol emerging

While SDN can take many forms, the open source OpenFlow protocol is one of the key and primary drivers in the market today. It’s an area that Cisco is now also actively developing too. “There are butts in seats and fingers on keyboards, pounding out the software for OpenFlow as well as extensions to that technology,” Ward said.

Ward noted that certain modules and protocols do certain things really well. In over 20 years of experience with protocols, WardRandom cloud image said that the biggest mistake is to take a single protocol connection and jam every single feature you want into that connection.

“At Cisco, we’re looking at a variety of protocols to take the architecture of OpenFlow and some of its limitations and we’re trying to go beyond that,” Ward said. “OpenFlow will be supported, but it’s yet to be determined which version will be productized.”

In Ward’s view there is a lot to like about OpenFlow. It’s a protocol that allows administrators to program state into a networking device without the need for the traditional transaction semantics for doing configuration.

That said, there are some issues with the architecture behind OpenFlow. At the top of Ward’s list is it is not easy to properly implement in hardware. “When you look at the definition of a virtual port in the OpenFlow specification there is no typing of that.”

Typing would define the specific type of port used, whether it’s a VLAN, GRE, physical or logical port and what the actual construct of the port is. With that contextual information, Ward noted that the right features can be applied.

OpenFlow is also challenging when it comes to the typing of tables. Ward noted that work is now ongoing to develop a generic forwarding plane description language and typing of particular elements.

“With that, we could put together a forwarding feature set that can be defined, described and can have a rule set for how to pass information,” Ward said. “OpenFlow 1.3 right now is very undefined, meaning tables are generic and ports are generic.”

Today, OpenFlow attempts to abstract all that information at the controller layer in an effort to be more open. The challenge is an application developer still needs to know the typing for every chip that they need to program.

“If you put it in the spec you’d have a generic and it could work with chips from Cisco, Huawei, Juniper, Broadcom etc.,” Ward said. “But, by shoving it up into the controller, you need to know the driver semantics to be able to know where the rules will work as there is no feature advertisement available today in the protocol.”

SDN is not a risk to Cisco in Ward’s view, it’s a big opportunity.

“The opportunity is to augment the existing Internet that we have today with the ability to extract and harvest intelligence and to program state into the network,” Ward said. “This will open us up for a rampant period of innovation.”

Sean Michael Kerner is a senior editor at, the news service of the IT Business Edge Network, the network for technology professionals Follow him on Twitter @TechJournalist.

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