Distributed sub-light-tree based multicast provisioning with shared protection in elastic optical datacenter networks

In an elastic optical network, it is critical to protect a multicast request against any single link failure with minimum spectrum consumption. However, conventional single light-tree based multicast provisioning schemes are spectrum inefficient with low modulation level employed. Since a multicast service can be hosted in multiple geographically-distributed datacenters in an elastic optical datacenter network (EODN), we construct several distributed sub-light-trees (DSLTs) to serve the users of a multicast request. Further, we protect each source-destination pair of a primary DSLT by a link-disjoint backup path against any link failure. Spectrum resource can be shared among the backup paths of different multicast requests (i.e., cross-sharing) or among the primary paths and the backup paths of the same multicast request (i.e., self-sharing) if they do not fail simultaneously. To formulate such a problem, an Integer Linear Program (ILP) is developed for a static traffic scenario. We also propose an efficient heuristic approach for the dynamic traffic scenario. Numerical results show that the proposed DSLT-based multicast provisioning with shared protection scheme outperforms conventional survivable multicast provisioning schemes based on single light-tree with or without shared protection in terms of spectrum efficiency and blocking probability.