Point-to-multipoint Virtual Link Embedding in Multi-domain SDN Networks

This paper proposes an approach based on Steiner trees to efficiently support point-to-multipoint communications in an SDN based multi-domain context, where each domain exposes a synthetic and aggregated view of its network. The approach that we propose is based on three pillars: The adoption of a topology aggregation of each domain's network as a Steiner tree, the adoption of global Steiner trees derived from the aggregated topologies as the embedding solution and the use of a shortest path heuristic for the computation of domains aggregated topologies as well as the global Steiner trees. Two resource allocation algorithms are proposed. The first addresses the case where network resources are abundant and, if expressed, the bandwidth requirement of the multipoint virtual link to embed can be easily supported by all links. The second algorithm assumes that network resources are limited and for some embedding requests some links may not be able to support the required bandwidth or some nodes may not have enough available entries in their flow tables. In this case, when possible, our algorithm computes a global tree that meets the requirements with the objective of minimizing the allocated resources as well as spreading network load. An experimental study on random and real network topologies assesses the performance of our approach in terms of both accuracy and computational complexity.