Survivability in IP over WDM networks

The Internet is emerging as the new universal telecommunicationmedium. IP over WDM has been envisioned as one of the mostattractive architectures for the new Internet. Consequentlysurvivability is a crucial concern in designing IP over WDMnetworks. This paper presents a survey of the survivabilitymechanisms for IP over WDM networks and thus is intended to providea summary of what has been done in this area and help furtherresearch. A number of optical layer protection techniques have beendiscussed. They are examined from the point of view of cost,complexity, and application. Survivability techniques are beingmade available at multiple layers of the network. This paper alsostudies the recovery features of each network layer and explainsthe impact of interaction between layers on survivability. Theadvantages and issues of multi-layer survivability have beenidentified. The main idea is that the optical layer can providefast protection while the higher layers can provide intelligentrestoration. With this idea in mind, a new scheme of carrying IPover WDM using MPLS or Multi Protocol Lambda-Switching has beendiscussed. Finally, an architecture is suggested by means of whichthe optical layer can perform an automatic protection switch, withpriority considerations with the help of signaling from the higherlayers.