<title>Multi-layer resilience in data-centric optical networks</title>

Abstract

Next generation automatic switched optical networks (ASON) show great promise in coping with increasing bandwidth demands, as they provide both on-demand bandwidth and improved switching flexibility. In a multi-layer data-centric network, such an ASON acts as a server layer and provides the topology for a client IP network. Multi-layer Traffic Engineering (MTE) enhances single-layer traffic engineering (i.e. adaptive routing) with the possibility to reconfigure the logical IP topology, utilizing the aforementioned optical flexibility in setting up and tearing down end-to-end lightpaths. To provide a robust network service, the multi-layer networks must be recoverable from different types of failures. Resilience mechanisms such as various forms of protection and restoration allow to recover from optical layer failures. In a multi-layer network however, some traffic will be forwarded through the IP layer routers, requiring a survivability scheme in this IP layer. This paper shows how MTE strategies that normally cope with changing traffic demands, can be used to provide this IP layer resilience. This is done through diverting affected IP traffic and replacing failing optical lightpaths, effectively leading to a dynamic restoration scheme. We will evaluate and compare failure performance of different types of resilience mechanisms, based on an existing MTE strategy.