Routers Distribution routers aggregate traffic from multiple access routers.

1. Routers forward data packets across computer networks. A Router checks the data packet for its destination address and protocol format details
2. When multiple routers are used in interconnected networks, the routers exchange information about destination addresses, using a dynamic routing protocol.
3. A router records a routing table listing what route should be used to forward a data packet, and through which physical interface connection. It does this using internal pre-configured addresses, called static routes.
4. The router forwards data packets between incoming and outgoing interface connections. It routes it to the correct network type using information that the packet header contains. It uses data recorded in the routing table control plane.
5. Routers may provide connectivity within enterprises, between enterprises and the Internet, and between internet service providers (ISPs) networks
6. All sizes of routers may be found inside enterprises.The most powerful routers are usually found in ISPs, academic and research facilities.
7. Access routers, including 'small office/home office' (SOHO) models, are located at customer sites such as branch offices that do not need hierarchical routing of their own
8. A core router resides within an Autonomous System as a back bone to carry traffic between edge routers.
9. Distribution routers aggregate traffic from multiple access routers, either at the same site, or to collect the data streams from multiple sites to a major enterprise location.
10. a  core router may provide a "collapsed backbone" interconnecting the distribution tier routers from multiple buildings of a campus, or large enterprise locations. They tend to be optimized for high bandwidth