Designing Controller Abstractions for Software-Defined Networks

Опубликовано 21 июня 2016, 21:52

Today's networks apply many different, yet often overlapping, pieces of control logic to packetized network traffic. Each packet must be routed, monitored, blocked, balanced, and/or redirected: dependent on both the packet's properties and operator requirements. Moreover, this control logic must constantly adapt to a changing landscape in which links go up and down; users arrive and depart; traffic demands fluctuate; hosts are compromised and patched; and operator requirements change. Software-Defined Networking (SDN) enables applications to realize these tasks by directly updating network switch routing tables. Yet, today’s popular SDN controller platforms provide only relatively low-level facilities for programming network switches. These controllers offer limited support for creating modular network controllers and, even less, for encoding dynamic control logic in a structured, compact, and intuitive manner. As a result, SDN controllers are challenging to write, hard to reason about, difficult to reuse or combine, and prone to bugs. In this talk, I will describe a progression of new programmer constructs and runtime concepts for SDN that are embodied in our Pyretic SDN Controller Platform and PyResonance Library. I will explain how together these provide a platform upon which better SDN controllers can be created. In particular, I will cover abstractions in both our SDN language and runtime architecture for supporting modularity, querying network state, and compactly encoding controller dynamics.