Multicast Tree Repair and Maintenance in the Cloud

Network virtualization enables the multi-tenancy concept where multiple tenants´s services can cohabit the same substrate network and share its resources. With multi-tenancy, the problem of allocating resources to the various tenants emerges as a challenging problem. This former is commonly known as the virtual network embedding problem (VNE), which has attracted numerous effort from the research industry due to its NP-Hard nature. Yet, most of the existing work overlook the various modes of communication a virtual network (VN) can exhibit, assuming it is always a one-to-one communication between virtual machines (VMs). The recent technological advancements (such as Software Defined Networks (SDNs)) have paved the way for efficient multicast in data center networks, thereby leveraging the support of services and applications which multicast data in large volumes. While much work has been devoted for studying the problem of multicast virtual network (MVN) embedding in the cloud, little attention has been paid to investigating the impact of failure on this service class. In this paper, we study the impact of facility node failure on embedded MVNs, and introduce a novel post-failure restoration scheme to repair failed MVNs while maintaining their requested Quality of Service (QoS). Our numerical results prove that our suggested method achieves encouraging restoration ratio in considerably fast execution time.