Designing a high availability subnetwork to support availability differentiation

In a recent series of papers [1-3] we studied the problem of how to provide both high levels of availability and service differentiation to traffic flows in a cost efficient manner. The basic idea developed was to embed at the physical layer a high availability set of links and nodes (termed the spine) in the network topology to support protection and routing in providing differentiated classes of resilience with varying levels of end-to-end availability. In this paper, we present an optimization model formulation of the spine design problem considering link availability and the cost of upgrading link availability. Numerical results show the advantages of modifying the availability of a subset of the network topology to provide QoR classes.