Routing; Overview - D-Link DFL-1600 User Manual

10.1

Overview

Routing is a major role in the network layer (OSI layer 3), which
determines how to transport packets from the initiating host to the desired
receiving end.
The devices functioning at the network layer, such as routers or firewalls,
perform routing to achieve two tasks primarily, the Path Determination
and the Packet Switching.
Path determination
Before any packet can be sent from the sender to the receiver, a path
need to be determined for the packet to travel through. Located in
the heart of any routing capable device, like a firewall or a router, is
the routing table, a map that provides all the path selections. Each
entry in this mapping table describes an available route.
The definition of the route here is the connection that links the two
communication ends and also all the intermediate routing devices.
The description of route inside the routing table indicates the address
of the receiver, and where is the next stop(hop) the packet should go
to get one step closer to its destination, since in the network
circumstance, it is common to have more than one device sitting
along the way. These contents are stored in the table as different
10
69

Routing