Network Virtualization: Paving the Way to Carrier Clouds (invited)

Network function virtualization (NFV) and multi- layer software-defined networking (SDN) will enable an automated control, management and orchestration of network resources across several network layers and areas. They may also open new possibilities for communication service providers (CSP) to expand their business and offer cloud services w ith carrier- level service-level agreements (SLA). In this paper, we briefly review technological, legal and business aspects of NFV and carrier clouds. Network function virtualization (NFV) is a current trend in the telecommunications industry that transforms tra ditional software and hardware components, i.e., functions f rom physical to virtual in order to enable cloud-like v irtualization and orchestration of network resources. NFV goes ha nd in hand with the software defined networking (SDN), which is a paradigm that provides for separation between the c ontrol and the data (switching or forwarding) planes. Both app roaches promise cost reduction and a rapid service delivery , i.e. an improved service agility and a revenue growth for n etwork operators. Recently, ETSI Industry Specification Gr oup for Network Functions Virtualization created several do cuments defining the architectural framework and requirements for NFV and addressing use cases for various network functions. Many component and system vendors already offer solutions that integrate SDN at different levels of implement ation and various network layers. Network operators already s how an increased interest in integrating SDN and NFV in th eir networks. Use cases include the virtualization of m obile networks (base stations, mobile core - EPC, IMS), c ontent delivery networks (CDNs), wired access networks as well as home/enterprise networks. The virtualization of net work resources opens new ways for network operators, i.e ., communication service providers (CSPs) to extend their business by integrating small and medium-scale data centers into their network infrastructure, thereby building carrier clouds and offering conventional and new cloud services with carrier-grade service level agreement (SLA). In this paper, we briefly review recent development s in NFV and SDN and indicate the main benefits and challenges of network virtualization and carrier clouds from t he technological, performance and legal aspects. II. CARRIER CLOUDS