We study methods for reducing the cost of secure link state routing. In secure link state routing, routers may need to verify the authenticity of many routing updates, and some routers such as border routers may needtosignmany routing updates. Previous work such as public-key based schemes either is very expensive computationally or has certain limitations. This paper presents an efficient solution, based on a detection-diagnosis-recovery approach, for the link state routing update authentication problem. Our scheme is scalable to handle large networks, applicable to routing protocols that use multiple-valued cost metrics, and applicable even when link states change frequently.
S. Cheung