Languages for Software-Defined Networks

Nate Foster, Michael J. Freedman, Arjun Guha, Rob Harrison, Naga Praveen Katta, Christopher Monsanto, Joshua Reich, Mark Reitblatt, Jennifer Rexford, Cole Schlesinger, Alec Story, and David Walker
IEEE Communications Magazine 51(2):128-134, 2013

Modern computer networks perform a bewildering array of tasks, from routing and traffic monitoring, to access control and server load balancing. Yet, managing these networks is unnecessarily complicated and error-prone, due to a heterogeneous mix of devices (e.g., routers, switches, firewalls, and middleboxes) with closed and proprietary configuration interfaces. Software- Defined Networks (SDN) are poised to change this by offering a clean and open interface between networking devices and the software that controls them. In particular, many commercial switches support the OpenFlow protocol, and a number of campus, data-center, and backbone networks have deployed the new technology. Yet, while SDN makes it possible to program the network, it does not make it easy. Today’s OpenFlow controllers offer low-level APIs that mimic the underlying switch hardware. To reach SDN’s full potential, we need to identify the right higher-level abstractions for creating (and composing) applications. In the Frenetic project, we are designing simple and intuitive abstractions for programming the three main stages of network management: (i) monitoring network traffic, (ii) specifying and composing packet-forwarding policies, and (iii) updating policies in a consistent way. Overall, these abstractions make it dramatically easier for programmers to write and reason about SDN applications.