NetCP: Consistent, Non-Interruptive and Efficient Checkpointing and Rollback of SDN

Abstract

Network failures are inevitable due to its increasing complexity, which significantly hampers system availability and performance. While adopting checkpointing and rollback recovery protocols (C/R for abbreviation) from distributed systems into computer networks is promising, several specific challenges appear as we design a C/R system for Software-Defined Networks (SDN). The C/R should be coordinated with other applications in the SDN controller, each individual switch C/R should not interrupt traffic traversing it, and SDN controller C/R faces the challenge of time and space overhead. We propose a C/R framework for SDN, named NetCP. NetCP coordinates C/R and other applications to get consistent global checkpoints, it leverages redundant forwarding tables in SDN switches for C/R so as to avoid interrupting traversing traffic, and it analyzes the dependencies between controller applications to make minimal C/R decision. We have implemented NetCP in a prototype system using the current standard SDN tools and demonstrate that it achieves consistency, non-interruption, and efficiency with negligible overhead.