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.
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.