what is router

A router is a device or a specialized computer which takes data packets from incomming lines, and decides outgoing lines on which to forward them.


A router is responsible for routing the data packets towards their destination.


A router is a device, which enables communication between two different networks or enables communication between two different series/classes of network.


A router is a internetworking device.


A router routes the packet from one logical network to other logical network.


The main job or function of router is to calculate the best path/route for the packet to reach to it’s destination. or


The main role of router is to determine the best path towards destination.


It determines where the data should go on the physical network.


It deals with, finding the way to the destination.


Types of Routers:


There are two types of routers: Fixed router and Modular router


Fixed router:


1. Parts in the router are inbuilt where modification to theinterface is not possible.


2. Access layer router are the exmple of fixed router except 1600 and 1700 series.


Modular Router:


1. Parts to the router can be added and removed i.e modification to the interface is possible.


2. Distribution and core layer router are the examples of modular router.






Cisco Routers are divided into 3 catagories or layers:


1. Access Layer Router


2. Distribution Layer Router


3. Core Layer Router


Access Layer routers are used by small organizations.Also knownas desktop or company layer routers. Router that are mostly used here are,router series – 800, 1000, 1600, 1700, 2500.

Distribution Layer router are used by ISP’s .Also known as IS layer routers.Router series – 2600, 3200, 3600, 3700.

Core layer router are used by global ISP’s .Also known as backbone routers. Router series – 6400, 7200, 7300, 7400, 7500, 7600, 10000, 12000.