Modeling recoverable connections in fault-tolerant ATM networks

摘要

As reliance on ATM networks increases, there is a corresponding increase in the need for reliability. One approach to fault-tolerance is to make the network selfhealing, by haivng the network automatically reconnect virtual paths disconnected by a failure. Existing recovery schemes suffer from an inability to provide multiple grades of reliability to higher lares when recovery occurs at a lower level. This paper introduces a new model of a virtual path, the variable priority virtual path, that allows the network to perform path level recovery that respects the priorities of individual circuits without segregating them onto separate VPs. We also discuss the impact of fault-tolerance on the user interface and propose an extension to existing service casses, degradable service, that is made possible by variable priority paths. We derive a novel multi-commodity flow problem, recovery flow, that captures both the bandwidth and QoS constraints of ATM. AN example is given of how the recover flow problem can be solved using integer programming techniques.