A framework for traffic engineering and routing in survivable multiservice high bit rates optical networks

This paper presents a general framework for Traffic Engineering (TE) of primary and backup paths and routing of Quality of Service (QoS) and Best-Effort (BE) flows in multi-service high bit rates optical networks capable of surviving against single or multiple node and/or link failure(s). The aforementioned framework involves an off-line and an on-line phase. In the off-line phase either a method based on a Integer Linear Programming (ILP) TE problem or a method based on a heuristic TE algorithm provides the primary and backup routes for the Qos-guaranteed flows, where backup paths are required, and the routes for the BE flows. In the on-line phase the QoS and BE flows are routed based on the outputs of the off-line phase. In the case that one or more primary paths fail the corresponding backup paths are used for restoration. However, if one or more backup paths also fail or a backup path is not defined, dynamic restoration is applied utilising a special source-routing algorithm. Implementation issues are also discussed and test results regarding the two off-line TE methods are presented.