A novel approach for protecting multicast sessions in metropolitan WDM ring networks

The introduction of the wavelength division multiplexing (WDM) into the metro environment and the rapid growth of multicast (single source and multiple destinations) applications such as video conferencing, distance learning, and online-auction initiated the need to realise multicasting in WDM metropolitan area networks (MANs) in a cost effective way. Because of their simplicity in maintenance, operation, and control, rings became dominant topologies in metropolitan networks. But, like in any other communication network, the optical network is also prone to link (fiber) failures. Because of the large amount of traffic a fiber carries, fiber failures in a WDM system would cause severe service loss or disruption. Hence, protecting such multicast sessions against link failures is an important cause of concern. This paper assumes a single link failure model and addresses the problem of multicast protection in the scenario of WDM metropolitan ring networks. The paper discussed the SONET like self-healing schemes based on unidirectional fibers and has proposed novel approaches which are based on bidirectional fibers.