Software-defined networking (SDN) can help businesses and service providers reduce networking complexity, as well as deployment and operational costs. These benefits are based on abstraction of the control functions from the network forwarding devices (such as switches, routers, and Layer 4 to 7 appliances). Abstraction helps simplify development or modification of new or existing services and applications, and that simplification drives costs down and contributes to faster revenue returns. Many people in the industry advocate the relocation of control functions to centralized general-purpose servers, typically x86 class in data centers. This approach offers lower costs through the use of lower-priced, mass-produced hardware for the forwarding devices.