Cisco Unveils OpFlex as Alternative to OpenFlow

The OpFlex protocol is the latest addition to Cisco's ACI effort, which gives organizations another option over other SDN platforms.

Cisco Systems is pushing forward with its Application Centric Infrastructure as an alternative to the software-defined networking platforms that are hitting the market. Now, the networking giant is unveiling a standards-based protocol that would play the same role as OpenFlow.

Cisco officials at Interop Las Vegas April 2 introduced OpFlex, southbound protocol that they said was developed alongside Citrix Systems, IBM, Microsoft and Sungard Availability Services. The companies are looking to make it an industry standard through the Internet Engineering Task Force (IETF).

Cisco executives, including CEO John Chambers, in November 2013 introduced the company's Application Centric Infrastructure (ACI), a strategy developed through its Insieme "spin-in" venture that looks to accomplish much of the same goals as software-defined networking (SDN)—create networks that are more automated, programmable, flexible and cost-effective.

SDN—which has been embraced by a wide range of tech vendors, from Hewlett-Packard, Dell, Juniper Networks and VMware as well as smaller startups—calls for network intelligence to be removed from expensive and complex physical gear and housed in software-based controllers. Many SDN proponents say that with this kind of technology, underlying physical switches and routers become less important.

However, Cisco officials have argued that getting the best results requires a combination of open and optimized hardware and software. The ACI initiative includes new switches—the Nexus 9000 lineup—as well as software like the Application Policy Infrastructure Controller (APIC), which helps unify the physical and virtual infrastructures throughout the data center.

OpFlex falls in line with that vision. Rather than keep the network policy and control in a software controller separate from the network, OpFlex pushes out policy onto the network to smart devices that can essentially automatically configure themselves, depending on the need of the applications, and then can reconfigure themselves as demand changes. The combination of APIC and OpFlex will enable organizations to leverage policy federation to manage applications in a scalable and multi-data center environment, according to Mike Cohen, director of product management for Cisco's Data Center Solutions unit.

In an interview with eWEEK, Cohen compared the two kinds of SDN control planes—imperative and declarative—to an airport environment. OpenFlow creates an imperative situation, where all the decisions about the traffic on the network are made centrally, as is seen in an airport baggage handling system; a centralized management system tells the baggage handlers which conveyor belts the bags go on, and the handlers follow the directions.

OpFlex creates a declarative control plane, which he likened to an airport control tower. Policies around the traffic are set in a central location, but the decisions on how to implement those policies are made by the network components themselves. This is similar to an airport control tower, which tells the airplanes where to go and when to take off and land, but then lets the pilots make the decisions in carrying out those policies.

Cisco's ACI creates a more scalable, interoperable and easier to use environment than SDN can, Cohen said. In an imperative model for SDN, the controller becomes a choke point as it manages all the requirements around applications and infrastructure configuration, Cisco officials said.

"The definition of SDN has been morphing a bit," he said, adding that ACI addresses the "need to bring together the physical and virtual pieces [of the network]."