ted a growth of 8000% of cellular data traffic over the past 4 years [1], and it grows to 10.8 exabytes/month by 2016, an 18-fold increase over 2011. To meet the constantly increasing traffic demands while maintain- ing or improving average revenue per user (ARPU), operators are always seeking new ways to reduce their operational expenditure (OPEX) and capital expenditure (CAPEX). One way to improve the cost-effectiveness of infrastructure is to introduce the concepts of scalable infrastructure and elastic capacity on demand, using virtual- ization and cloud computing, which have become the cornerstones of many successful large-scale IT infrastructure management. Thanks to their successful deployment in Internet companies such as Google and Amazon, emerging cloud computing technologies have started to be borrowed and deployed in the telecom network, in the form of software-defined networking (SDN) and network functions vir- tualization (NFV). The SDN design introduces a separation between the control and forwarding components of the network. Among the use cases of such architecture are the access/aggregation domain of carrier-grade networks, mobile backhaul, cloud computing, and multilayer (e.g., Internet Protocol (IP), Ethernet, Optical Transmis- sion Network (OTN), and wavelength division multiplexing (WDM)) support, all of which are among the main building blocks of today's network infrastructure. Unlike the traditional network architecture, which integrates both forwarding (data) and control planes on the same box, SDN decouples these two and runs the control plane Preface on servers that might be in different physical locations from the forwarding elements (switches). It allows making the forwarding platform simple and bringing network's intelligence into a number of controllers that oversee the switches. Tight coupling of forwarding and control planes in the traditional architecture usually results in overly complicated control plane and complex network management and is known to create a large burden and h