Lagopus is a high-performance, open source software switch, primarily for DPDK on Linux, developed at NTT in its Network Innovation Laboratories research group. Lagopus features OpenFlow 1.3 conformance, plus extensions to better support NTT's use cases. This episode is a discussion with Yoshihiro Nakajima, one of the switch's developers, about Lagopus, its history, goals, and future.

Lagopus supports protocols that are particularly important to carriers, such as PBB and MPLS, and includes OpenFlow extensions for general-purpose tunnel support with VXLAN, GRE, and other encapsulations. Yoshihiro talks about how, with DPDK, Lagopus implements some protocols, such as ARP and ICMP, by delegating them to the Linux kernel through TAP devices.

Yoshihiro describes the architecture of Lagopus and how it achieves high performance. It has optimizations specific to the flows that each table is expected to contain; for example, a different lookup implementation for L2 and L3 tables. We talk about how the number of tables in a given application affects performance.

Lagopus targets two main application domains: high-performance switching or routing on bare-metal servers, or high-performance virtual switching for NFV. Some of the latter applications are in a testing phase, aiming for ultimate production deployment.

We discuss some philosophy of SDN (some audio was lost at the beginning of this discussion). The important part of SDN, to Yoshihiro, is to avoid the need to use CLIs to configure switches, instead moving to a “service-defined” model.

We discussed how to fit stateful services into the stateless OpenFlow match and action pipeline model, particularly how to handle the need for sequence numbers in some tunneling protocols such as GRE and GTP.

We talk about the difficulties in forming an open source community around a software switch and attracting contributions from a group outside the immediate organization writing the software. Yoshihiro reports receiving reports from several users, including suggestions for improvement.

Lagopus has a growing worldwide community but some of the outreach from the team has focused on Asia in general and Japan in particular because of lower geographical and communication barriers.

The Lagopus team is currently working on a switch and routing control API that works at a higher level than OpenFlow, based on YANG models.

OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space

Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0

Unported (CC BY 3.0) license.