A comparative analysis of two-stage approaches for embedding network function virtualization enabled multicast services

The Network Function Virtualization (NFV) technology has emerged to turn hardware-based network functions into software-based virtual entities. In NFV-enabled multicast services, the data flow should be passed through a series of Virtual Network Functions (VNFs) before reaching destinations. In the problem of NFV-enabled multicast service embedding, not only the VNFs must be deployed, but also the traffic forwarding topology must be constructed. As the exact solution of this problem suffers from high computational complexity, the heuristic or approximation approaches are used in practice. However, as a way to control the trade off between complexity and efficiency, using multistage solutions is offered in literature. In this article, some two-stage approaches for embedding NFV-enabled multicast services are introduced, and they are compared through analysis and simulation. Specifically, a new low-complexity approach based on the Auxiliary VNF Graph (AVG) is proposed to determine the sub-optimal locations for VNF placement and to construct the NFV-based multicast routing tree. The comparative analysis shows that the proposal has acceptable performance while reducing the computational complexity significantly.