Grooming of Survivable Multicast Sessions Against Single Link Failures in Sparse Splitting WDM Mesh Networks

Cost effective grooming of several sessions with fractional wavelength bandwidth onto a single wavelength has become prominent in WDM networks. We, in this paper, address the problem of survivable routing and wavelength assignment of multicast sessions with sub-wavelength traffic demands in sparse splitting WDM networks. We assume a sparse splitting node architecture in which only a few nodes in the network are split-capable. A node with splitting capability can forward an incoming message to more than one outgoing link in the optical form. The multicast capability at the non-split nodes can be achieved by converting the optical signal into electronic form and transmitting in optical form onto all the required outgoing links. However, the traffic duplication at the electronic level is more expensive than the optical level in terms of the delay incurred due to the optical-electronic-optical (O/E/O) conversion. Since the multicast traffic grooming problem is computationally intractable, we adopt a heuristic approach called VSGroom which tries to minimize the resources required for electronic copying. We extend the notion of link disjoint, arc disjoint and path disjoint protection methodologies to groomed multicast sessions in order to protect them from single link failures. The performance of the various protection algorithms is studied and compared through extensive simulation experiments.