Survivability in IP over WDM networks

The Internet is emerging as the new universal telecommunication medium. IP over WDM has been envisioned as one of the most attractive architectures for the new Internet. Consequently survivability is a crucial concern in designing IP over WDM networks. This paper presents a survey of the survivability mechanisms for IP over WDM networks. A number of optical layer protection techniques have been discussed. They are examined from the point of view of cost, complexity and application. The case of survivability at multiple layers has been considered. The advantages and issues of multi-layer survivability have been identified. The main stressed idea is that the optical layer should provide fast protection while the higher layer should provide intelligent restoration. With this idea in mind, a relatively new scheme of carrying IP over WDM using MPLS or Multi Protocol Lambda-Switching has been discussed.