PQ Show 64: OpenFlow TTPs Won’t Save Us with Rob Sherwood

On this Packet Pushers Priority Queue, we interview Rob Sherwood, CTO of Big Switch Networks, to gain an alternate view on OpenFlow TTPs (table type patterns). We first talked about TTPs in Weekly 220 in a discussion with Curt Beckmann back in January 2015. While Curt was fairly enthused that TTPs were going to move the ball forward, Rob is not convinced that TTPs are the long-term answer to make it easier for OpenFlow controllers and switches to share capabilities. What We Discuss * How OpenFlow is used by a switch to make decisions * What tables are used by a switch to store actionable information impacting packet forwarding * How TTPs describe these tables – the schemas that TTPs provide * Why defining specific TTP schemas is short-changing hardware capabilities in some silicon, and might even result in sub-optimal performance in specific operations * The emergence of P4 as a “language of constraints” * Silicon manufacturers obfuscate details of their specific chips as a competitive advantage. That puts TTPs that describe switching capabilities generically at a disadvantage. Without knowing specifics, it’s probably not possible to write a TTP that will result in a chip being used optimally * TTP is the best solution we have today. But perhaps not tomorrow Links Weekly 220: OpenFlow + Table Type Patterns with Curt Beckmann Rob Sherwood on Twitter