Survivable Virtual Topology Mapping in IP-Over-WDM networks using differential evolution optimization

In IP-over-WDM networks, a virtual topology is placed over a physical topology of the optical network. Since a simple link failure or a node failure on the physical topology can lead to a huge loss of information, an important challenge is to make the routing of the virtual topology on to the physical topology survivable. This problem is known as the Survivable Virtual Topology Mapping (SVTM), which is an NP-complete problem. So far, this problem has been analysed using heuristic strategies or by the application of optimization tools. In this paper we introduce the application of Differential Evolution (DE) to solve the SVTM problem. The method typically requires few control parameters. An illustrative example is presented showing the effectiveness and efficiency of the proposed algorithm. To the best of our knowledge, our work is the first application of a DE algorithm to the SVTM problem.

1. INTRODUCTION

Considering the IP level restoration scenario in IP-over-WDM networks [1], an important challenge is to make the routing of the virtual topology (VT) on to the physical topology (PT) survivable. To achieve the IP restoration level the virtual topology needs to remain connected after a failure occurs. The failure can be of many types: node failure, link failure or multiple link failure. Single link failure is the most common failure in optical networks. The problem of routing virtual links into a physical topology in such a way that the virtual topology (lightpaths set up on the physical network) remains connected after a physical link failure is known as the Survivable Virtual Topology Mapping (SVTM) problem. This combinatorial problem is an NP-complete problem [2].