On Diagnosis of Forwarding Plane via Static Forwarding Rules in Software Defined Networks

TL;DR

This paper proposes methods to install minimal static forwarding rules in SDN switches, enabling rapid topology verification and link failure detection without controller communication, achieving near-optimal rule count and sub-second localization.

Contribution

It introduces solutions for static rule placement that allow fast, controller-independent topology verification and failure detection with near-optimal rule efficiency.

Findings

Near-optimal static rule placement within 14% of optimal

Sub-second link failure localization at data-center scale

Latency of tens of milliseconds for networks with thousands of links

Abstract

Software Defined Networks (SDN) decouple the forwarding and control planes from each other. The control plane is assumed to have a global knowledge of the underlying physical and/or logical network topology so that it can monitor, abstract and control the forwarding plane. In our paper, we present solutions that install an optimal or near-optimal (i.e., within 14% of the optimal) number of static forwarding rules on switches/routers so that any controller can verify the topology connectivity and detect/locate link failures at data plane speeds without relying on state updates from other controllers. Our upper bounds on performance indicate that sub-second link failure localization is possible even at data-center scale networks. For networks with hundreds or few thousand links, tens of milliseconds of latency is achievable.