I. Introduction
In recent years, the Internet has been growing at a rapid pace, and currently consists of over 5 billion nodes [11]. This growth has been supported by the development of high performance networking hardware, made possible by the continuous advancements in semiconductor technology. Network virtualization [1], [2] was proposed to take advantage of these advancements to improve network efficiency. This has been realized via router virtualization, at the hardware level. Router virtualization allows multiple network hardware to be consolidated onto a single shared platform, thereby enabling centralized management of multiple networks. Reduced hardware costs, reduced power consumption, and ease of management are a few additional benefits. These features have become attractive especially in the context of datacenter networking and Software Defined Networking (SDN) [4].