AT&T Picks Barefoot Networks for Programmable Switches

AT&T is the first telecommunications provider to announce using programmable switches from Barefoot Networks in its network.

Barefoot Networks last summer was the first company to announce a switch operating 6.5 Tb/s. It roughly doubled the previous speed record. The company’s Tofino ICs were also the first programmable switches announced. Tofino silicon began sampling only in December.

AT&T has installed Tofino-based white boxes running SnapRoute’s FlexSwitch Network Operating System (NOS) in parts of its existing MPLS-based networks. AT&T exploited the programmability of the chip to add In-band Network Telemetry (INT).

AT&T’s experience is a validation of programmability in switching in general, and of its Tofino products in particular, explained Ed Doe, Barefoot Networks’ vice president of product management and marketing. AT&T completed the entire project in weeks, including creating a version of INT specifically for MPLS networks, Doe told SDxCentral.

Previously, anyone wanting to add a differentiating feature such as INT would have to work with a semiconductor company to design it into the next generation of chips. And IC development cycles can stretch to two years.

Barefoot had been talking about telemetry as an application that could benefit from data plane programmability for at least a couple of years, Doe noted (switch ICs like Tofino operate in the data plane). In collaboration with Arista, Dell, Intel, VMWare, and others, Barefoot put out a specification with the P4 Organization, which develped a programming language for Tofino and other programmable ICs.

Facebook was intrigued by that proposal, but Facebook uses the UDP protocol, so Barefoot and Facebook co-wrote a spec for that, which is now the basis for the IETF’s In Situ OAM. AT&T, in turn, was intrigued by In Situ OAM, but nothing like it existed for MPLS, Doe explained, so it wrote its own version of INT for Barefoot’s Tofino running in an MPLS network.

Barefoot is at the Open Networking Summit (ONS) in Santa Clara, California, this week with a demonstration that closely parallels what AT&T is doing. It includes Barefoot Tofino based 6.5Tb/s Wedge 100B switches from EdgeCore along with SnapRoute’s FlexSwitch network operating system.

Barefoot and SnapRoute

Barefoot is also touting a new level of granularity in network visibility that Tofino-based systems can provide in conjunction with SnapRoute. Barefoot said the two companies can report on every single packet’s path and latency.

Furthermore, a Tofino-based system running SnapRoute is particularly adept when it comes to the difficult task of detecting microbursts in network traffic. A large microburst can disrupt a network, but occur so rapidly it might not otherwise be detected. With Tofino, network operators can not only see these microbursts real-time but also identify the aggressor and victim flows, giving full visibility into the identity of the offending application, according to Barefoot Networks.

Ultimately, that improves a service provider’s ability to guarantee service level agreements (SLAs) to their customers. Barefoot is demonstrating this capability at ONS as well.