Link-coloring based scheme for multicast and unicast protection

We propose a computationally efficient link-coloring based scheme that facilitates end-to-end protection for dynamic multicast and unicast connections. For a given source node, links are colored as red or blue such that, for any destination node, the red and blue paths are guaranteed to be node disjoint. Red and blue trees, constructed using only the red and blue links, respectively, always form redundant trees (RTs) independent of the used tree selection method. RTs connect the source of a multicast connection to all its destinations in such a way that in the event of a single link or node failure in the network, every destination is still connected to the source in at least one of the two trees. In network topologies where such RTs cannot be constructed due to lack of required path diversity, our scheme constructs two multicast trees such that the red and blue paths to any destination node only share cut links or nodes. To our knowledge, our scheme is the first that can construct such RTs. Although finding the optimal RTs is known to be NP-complete, extensive simulations show that our scheme calculates near optimal RTs and substantially outperforms other solutions.