L Depré

Recovery in multilayer optical networks

The integration of different network technologies into a multilayer network, as in Internet-based networks carried by optical transport networks (OTNs), creates new opportunities but also challenges with respect to network survivability. In different network layers, recovery mechanisms that are active can be exploited jointly to reach a more efficient or faster recovery from failures. This interworking is also indispensable in order to overcome the variety of failure scenarios that can occur in the multilayer-network environment. A well-considered coordination between the different layers and their recovery mechanisms is crucial in order to attain high performance recovery. This paper provides an overview of multilayer recovery issues and solutions in an Internet protocol (IP)-over-optical-network environment, which is illustrated by quantitative case studies.

A Quantitative Comparison of Some Resilience Mechanisms in a Multidomain IP-over-Optical Network Environment

When we examine todays internet architecture, we notice that the IP layer network is divided into multiple domains, managed by different service providers, operating different architectures, providing different services, handling different business strategies. In order to provide survivable inter-domain connections, to ensure connectivity in case of the most prevalent failures, different strategies can be followed. In this paper, we present some multidomain resilience schemes for a single optical backbone network interconnecting different IP domains. We then present a quantitative study of the network capacity required, in a specific pan-European backbone network.

Recovery strategies in multilayer networks

Due to a continuous stream of technological advances, enormous amounts of traffic are aggregated onto a single fiber. The main drive for this is the cost savings that are realized due to the economy of scale. However, a major drawback is the impact of a single failure (e.g., cable cut), which can become very and even unacceptably large. This paper aims at discussing the different techniques that can be applied to deal with such circumstances.