Internet2 has moved its production network off of OpenFlow, putting users back onto MPLS for now, a step that seems retrograde but is also meant to be temporary.

In other words, Internet2 is not giving up on software-defined networking (SDN). The organization has now separated its production and research networks, and the latter still has OpenFlow 1.0 available, with OpenFlow 1.3 support likely to be ready in the third quarter, says Rob Vietzke, Internet2's vice president of network services.

But for the production network, which serves as a backbone connecting universities and research institutions, backtracking to MPLS will give users some of the features they've been craving and that Internet2's vendors couldn't get working in OpenFlow 1.0.

"Internet2 is just as bullish on SDN as it was a couple of years ago. OpenFlow 1.0 is just not there," Vietzke says. "We've had three-and-a-half years of production networking on 1.0, and it's given us a great run."

The shift back to MPLS was announced during Internet2's 20th anniversary conference, held in Chicago earlier this month.

While Internet2 serves a practical use, it's also available as an experimental playground, a place for testing new theories around computer science and networking.

SDN was an obvious fit there. Internet2 began using OpenFlow 1.0 for Layer 2 networking about three-and-a-half years ago, with Layer 3 support available in the form of VLANs riding atop the Layer 2 network.

In 2014, Internet2 also introduced a network virtualization capability, letting users create their own private networks on the consortium's 100-Gb/s backbone.

Since then, OpenFlow advanced to version 1.3, but Internet2 found itself still stuck on version 1.0.

Moving to 1.3 proved problematic, partly because vendor support "has gotten softer," Vietzke says. Vendors aren't feeling the same red-hot urgency to support OpenFlow as they did in 2013.

That led to another problem. Production users began requesting features such as quality-of-service (QoS) or the VLAN stacking technology known as QinQ, and Internet2's vendors couldn't get them to work in OpenFlow 1.0. A faster solution was to have users go back to MPLS.

But that doesn't mean Internet2 is abandoning SDN, Vietzke stresses.

"No one is going back on the drive to have that complete network programmability, and for Internet2, it's in our wheelhouse to provide that kind of programmability. What form it takes is not clear right now, whether it's OpenFlow 1.3 or P4 or whatever," Vietzke says.

That next SDN step could also involve new equipment choices; Vietzke rattles off possibilities such as white box switches or Corsa’s programmable data plane. The goal is to devise a plan during the next year that can be executed in 2018.

Meanwhile, the research network is indeed going to get OpenFlow 1.3, later this year. The test bed is being set up now and should be completed during the third quarter, Vietzke says.

Photo: K. Kendal on Flickr. CC2.0 license. Photo has been cropped.