Relaxed Failure Recovery Process for Reliable Quality-of-Service using Unreserved Backup Paths

Guaranteed, high-quality service in the computer network often requires a single reserved path. However, a single path can easily suffer from single point failures. This paper provides a solution to handle flows when their reserved primary paths fail. The solution pairs a reserved primary path with an unreserved backup path. When a failure occurs and a primary path fails, the initial service guarantee is relaxed slightly, and the flow with the failed primary path is re-routed on the least congested alternate path. This approach allows all flows to continue despite a failure in the network. In addition, even though the service quality is relaxed to accommodate flows with failed primary paths, by carefully planning the least congested alternate paths as backups, very high levels of service quality can still be retained after failure.