Internet Routing Dynamics and NSIS Related Considerations

Design of Next Step In Signaling (NSIS) protocol and IP routing interaction requires a good understanding of today's Internet routing behavior. In this report we present a routing measurement experiment to characterize current Internet dynamics, including routing pathology, routing prevalence and routing persistence. The focus of our study is route change. We look at the types, duration and likely causes of different route changes and discuss their impact to the design of NSIS. We also review common route change detection methods and investigate rules to determine whether a route change happened in a node's forward-looking or backward-looking direction is detectable. We introduce typical NSIS deployment models and discuss specific categories of route changes that should be considered in each of these models. With the NSIS deployment models in mind, we further give experimental evaluation of two route change detection methods - the packet TTL monitoring method and a new delay variation monitoring method.