In the past year, the ONF has morphed into a different beast. In fact, some people involved with open source networking are referring to the group as “the new ONF.” It has merged with On.Lab. Its new executive director, Guru Parulkar, is placing emphasis on the group’s popular Central Office Re-architected as a Data Center (CORD) projects. And now, the P4 programming language is breathing new life into OpenFlow.
OpenFlow is all about separating the forwarding plane from the control plane in networks. “OpenFlow was the first to do that,” said Timon Sloane, VP of marketing at the ONF, speaking with SDxCentral at the SDN and NFV World Congress this week. “P4 is poised to usher in the next wave: true programmability. The P4 language makes the chip layer programmable so you can do dynamic things to packets.”
Sloane explained that the forwarding plane is defined by the ASIC capability in the hardware. And every vendor has a different pipeline of hardware and chip capability. “OpenFlow exposed this pipeline so it could be controlled,” he said. “But tweaks were required in the controller every time you tried to do something different.”
Now, with advancements in ASICs, these pipelines can be programmed with P4. Specifically, P4 creates the table entries in the ASICs, and the new P4 Runtime enables controllers to speak to the table entries.
Just last week, Google Cloud and Barefoot Networks announced they had created an open source P4 Runtime application programming interface (API). It’s designed for control plane software and is independent of the underlying forwarding plane type. It offers the ability to control a variety of networking devices including software switches and programmable ASICs.
“P4 is an amazing innovation,” said Sloane. “It’s putting in the hands of software developers the ability to program the network.”
Dan Pitt, who was the ONF’s original executive director and is now the senior vice president at MEF, said P4 “is a language to program the forwarding plane of a programmable chipset. We haven’t had too many programmable chipsets.”
At this point, there are programmable chipsets from Broadcom, the Xpliant chipset bought by Cavium, and the Tofino chipset from Barefoot Networks. “I hear rumors that other well-known chip companies are developing the same capacity,” said Pitt.
From ONF’s perspective, the forwarding plane, in its CORD projects, is comprised of general purpose servers that talk to the controller using OpenFlow. With P4-enabled chips, this underlying fabric can become programmable, offloading functions to the hardware itself.
Speaking about P4 last week, Nick McKeown, who was involved with P4 early on, envisioned a scenario where operators could run CORD racks on top of ONOS with P4 below to program operations. “When you can program the control plane of the network, it makes sense for these operators to want to change the forwarding plane as well,” McKeown said. “It’s an easy way to change behavior on the network.”