🤖 AI Summary
This work addresses the challenges of in-band SDN control planes in resource-constrained wide-area telecommunication networks, including autonomous bootstrap, source routing, sub-50ms failure recovery, and multi-controller coordination. The authors propose Periplus, a system that embeds a forwarding graph—encoding both primary and per-hop backup paths—into L2/L3 packet headers. This design enables controller-independent local failover within 50 milliseconds and facilitates switch bootstrap with minimal flow table overhead. Notably, only two switches require initial configuration, eliminating network-wide flooding during provisioning. Flow table occupancy is decoupled from network size, scaling only at nodes that encode multipath information. Experimental evaluation using Ryu and Open vSwitch (augmented with Nicira extensions for NSH encapsulation) demonstrates Periplus’s capabilities in rapid recovery, scalable bootstrapping, and efficient resource utilization.
📝 Abstract
Many resource-constrained, wide-area telecommunications deployments could benefit from an in-band SDN control plane, but several challenges stand in the way. This paper presents Periplus, an in-band SDN control plane designed to address four challenges that this approach presents in such contexts: automatic bootstrapping, source-based routing, fast failure recovery, and multi-controller coordination. The first three are developed in detail, while multi-controller coordination is addressed in a separate paper. For bootstrap, Periplus avoids network-wide flooding: when a new switch joins, the controller installs flow rules in only two switches. For routing and failure recovery, Periplus encodes a primary path and per-hop alternatives in a graph structure encapsulated between L2 and L3 headers; switches forward along the primary path and, upon detecting a failure, fall over locally to the encoded alternative without controller involvement. We evaluate a Ryu-based implementation of Periplus in Mininet across multiple topologies. Periplus runs on stock Open vSwitch (OVS), relying only on its built-in Nicira extensions for Network Service Header (NSH) encapsulation. The evaluation shows sub-50 ms failure recovery, scalable bootstrap across topologies of varying size and diameter, and a per-switch flow-table footprint that is independent of network size and grows only at switches where the controller encodes multiple alternatives.