Networking Guide : Network Components


Router functions to forward packets across different networks. Router maintains a routing table. The routing table contains IP addresses of other networks routers. In a static router the routing table is configured manually, while a dynamic router can communicate with other routers and configure the routing table according to information it receives from other routers.

Router function in OSI Model protocol stack

Picture: Router in OSI Model protocol stack
Router is a (OSI's) Layer 3 device.
Packet goes through the protocol stack from its source to its destination.

When receiving a packet, a router examines the packet destination IP address and forwards it to its destination by looking at the routing table. Router determines the best path to deliver a packet based on the routing algorithm it uses, usually the path will be the shortest and the most reliable.

In publications, router is often named according to its capacity or its position in the network. You may find these terms: edge router, core router, backbone router. And a type of router specially designed for home Internet users, is commonly known as residential gateway.

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