Networking: A killer app for programming languages researchers


May 13, 2013


David Walker


Princeton University


Modern computer networks perform a bewildering array of tasks, from routing and traffic monitoring, to access control and server load balancing. Moreover, historically, managing these networks has been hideously complicated and error-prone, due to a heterogeneous mix of devices (e.g., routers, switches, firewalls, and middleboxes) and their ad hoc, closed and proprietary configuration interfaces. Software-Defined Networking (SDN) is poised to change this state of affairs by offering a clean, simple and open interface between network devices and the software that controls them. In particular, many commercial switches now support the OpenFlow protocol, and a number of campus, data-center, and backbone networks have deployed the new technology.

However, while SDN makes it possible to program the network, it does not make it easy: The first generation of SDN controllers offered application developers the “assembly language” of network programming platforms. To reach SDN’s full potential, research in programming languages and compilers is desperately needed. In this talk, I discuss our work to date on the Frenetic project, which involves the design of language, compiler and run-time system support for SDN programming. Our languages allow programmers to work declaratively, specifying global behaviors of their network at a high level of abstraction. The compiler and run-time system take care of the tedious details of implementing these high-level policies using the OpenFlow protocol.

A key strength of our design is its support for modular programming. Complex network applications can be decomposed in to logical subcomponents — an access control policy, a load balancer, a traffic monitor, a router — and coded independently. Frenetic’s rich combinator library makes it possible to stitch such components back together to form a fully functioning whole. In this talk, we will discuss our latest design ideas, including technology that allows programmers to define abstract, virtual networks and isolated network slices. We will also touch on the semantics of Frenetic, explain some of its key properties, and describe a few of the algorithms needed to implement it.


David Walker

David Walker is a Professor of Computer Science at Princeton University, having received tenure in July 2008 and the rank of full professor in February 2013. He received his B.Sc. from Queen’s University (Canada) in 1995 and his Ph.D. in Computer Science from Cornell University in 2001. At Princeton, he studies programming languages, compilers, type systems, and domain-specific languages. After arriving at Princeton in February 2002, he won an NSF Career award in 2003 and Alfred Sloan Fellowship in 2004. In 2007, with his students and colleagues at Princeton, he won the PLDI best paper award for the paper entitled “Fault-Tolerant Typed Assembly Language.” In 2008, his paper “From System F to Typed Assembly Language,” co-authored with Greg Morrisett, Karl Crary and Neal Glew, won a 10-year retrospective award for the highest impact POPL 1998 paper. In 2013, with his students and colleagues at Princeton and Cornell, he won the NSDI community award for his paper on “Composing Software-Defined Networks.” He is currently serving as an associate editor for the ACM Transactions on Programming Languages and Systems and for Foundations and Trends in Programming Languages.