|  | 11.5 | The Context of Different Routing Protocols
| 11.5.5 | Path selection and switching of multiple protocols and media
Routers are devices that implement the network service. They provide interfaces for a wide range of links and subnetworks at a wide range of speeds. Routers are active and intelligent network nodes that can participate in managing a network. Routers manage networks by providing dynamic control over resources and supporting the tasks and goals for internetwork connectivity, reliable performance, management control, and flexibility. In addition to the basic switching and routing functions, routers have a variety of additional features that help to improve the cost-effectiveness of the internetwork. These features include sequencing traffic based on priority and traffic filtering. Typically, routers are required to support multiple protocol stacks, each with its own routing protocols, and to allow these different environments to operate in parallel. In practice, routers also incorporate bridging functions and sometimes serve as a limited form of hub.