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Google Cloud using P4Runtime to build smart networks

April 2, 2018
Jim Wanderer

Engineering Director

Amin Vahdat

VP/GM, Machine Learning, Systems, and Cloud AI, Google Cloud

Data networks are difficult to design, build and manage, and often don’t work as well as we would like. Here at Google, we deploy and use a lot of network capacity in and between data centers to deliver our portfolio of services, and the costs and burdens of deploying and managing these networks have only grown with the the scale and complexity of these networks. Almost ten years ago, we took steps to address this by adopting software-defined networking (SDN) as the basis for our network architecture. SDN allowed us to program our networks with software running on standard servers and became a fundamental component of our largest systems. In that time, we’ve continued to develop and improve our SDN technology, and now it’s time to take the next step with P4Runtime.

We are excited to announce our collaboration with the Open Networking Foundation (ONF) on Stratum, an open source project to implement an open reference platform for a truly "software-defined" data plane, designed and built around P4Runtime from the beginning. P4 Runtime allows the SDN control plane to establish a contract with the dataplane about forwarding behavior, and to then establish forwarding behavior through simple RPCs. As part of the project, we’re working with network vendors to make this functionality available in networking products across the industry. As a small-but-complete SDN embedded software solution, Stratum will help bring P4Runtime to a variety of network devices.

But just what is it about P4Runtime that helps with the challenges of building large-scale and reliable networks? Network hardware is typically closed, runs proprietary software and is complex, thanks to the need to operate autonomously and run legacy protocols. Modern data centers and wide-area networks are large, must be fast and simple and are often built using commodity network switch chips interconnected into a large fabric. And despite high-quality whitebox switches and open SDN technology such as OpenFlow, there still aren’t a lot of good, portable options on the market to build these networks.

At Google, we designed our own hardware switches and switch software, but our goal has always been to leverage industry SDN solutions that interoperate with our data centers and wide-area networks. P4Runtime is a new way for control plane software to program the forwarding path of a switch and provides a well-defined API to specify the switch forwarding pipelines, as well as to configure these pipelines via simple RPCs. P4Runtime can be used to control any forwarding plane, from a fixed-function ASIC to a fully programmable network switch.

Google Cloud is looking to P4Runtime as the foundation for our next generation of data centers and wide area network control-plane programming, to drive industry adoption and to enable others to benefit from it. With P4Runtime we’ll be able to continue to build the larger, higher performance and smarter networks that you’ve come to expect.

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