Forwarding network mainly forwards packets at the behest of the control network and the management network. The forwarding network consists of forwarders. The forwarders mainly perform the user data processing tasks, such as packet classification, packet scheduling, packet forwarding, traffic shaping, packet filtering, and so on. The main difference between a forwarder and a traditional router is that it does not perform the route calculation and policy processing. There is a special kind of forwarders called separators, which are located in the edge of forwarding network and used to block the end system access to core networking devices.