ONF Connect 2018

In this talk I would like to present few approaches, which networking gear vendors can consider to incrementally introduce P4 in their existing product line. I would like to introduce the approaches of “Stratum controlled P4 Sandboxes” and “Pushing P4 defined forwarding pipeline chunks through control plane’s northbound API”. We have successfully tried these approaches in Juniper. To give practical example I would introduce the specific use case of “Flexible Tunnels” in which a controller controls a part of forwarding plane topology, defined in P4, to define and dynamically change tunnel encapsulations in data plane.

These pragmatic approaches, apart from providing a reasonable path for networking vendors to adopt P4, would make a lot of sense for various reasons. Existing data plane code (think of NPUs) of various networking vendors has value which has been created over a long period of time. Defining (re-writing ) the complete data plane in P4, which would involve compiler backend changes and changing the existing local control planes’ south-bound interface to P4Runtime) for all the features, which are currently supported by vendors’ routers and switches, would require significant development and testing efforts. Moreover, some customers may not want to assume complete ownership of control plane. They may not either be equipped (read resource constraints) or do not want to handle/rewrite P4 enabled control plane (even if vendors are willing to provide P4 programmable data plane) for features which are already available from vendors’ existing field-proven control-plane and data-plane code of the vendors.