A novel approach for ensuring high end-to-end availability: The spine concept

Telecommunications networks need to guarantee that all node pairs involved in critical service communications are highly available. Typically only a small fraction of traffic and users needs high levels of availability but this traffic often drives the network design to over engineering. In this paper we adopt a novel approach to the problem of how to provide high levels of availability in an efficient manner. The basic idea is to embed a high availability set of links and nodes (termed the spine) in the network topology and leverage protection and routing to provide differentiated classes of resilience with varying levels of availability. In this paper we first explore the spine concept through a simple example illustrating the potential benefits of the approach. Then we study how the structural properties of a network topology can be used to determine heuristics to select a suitable spine and compare this with the case where all network components have the same availability. This is followed by a numerical based study comparing the heuristics with all possible spanning tree based spines for sample topologies. Our results are a step along the path of how to best design a physical network to support protection methods in achieving high levels of availability cost efficiently.