Service Availability in IP Networks

Recent studies reveal that Internet backbones are capable of providing very low loss rates and end-to-end delays close to the speed of light (in optical fiber). However link failures may lead to packet losses, delay variations and outages due to missing or inconsistent forwarding information in routers. Link failures occur everyday, and may ultimately affect the quality of service experienced by an ISP's customers. On the other hand, not all link failures impact customer service. Therefore we advocate the need for a new metric to characterize IP service availability in the presence of link failures. We analyze the various factors affecting service availability in IP networks, and explore how to define this metric