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Posts Tagged ‘What Is The Function Of Router?’

What Is The Function Of Router?

A router is specialized computer connected to more than one network. A router runssoftware that allows the device to move data from one network to another. Routers operate at the network layer (OSI Model’s layer 3). The primary function of a router is to connect networks together and keep certain kinds of broadcast traffic under control. There are several companies that make routers: Cisco (Linksys), Juniper, Nortel (Bay Networks), Redback, Lucent, 3Com, and HP just to name a few.

Why do I need a Router?

Routers used in networks perform the following functions:

  • Restrict network broadcasts to the LAN
  • Act as the default gateway.
  • Move data between networks
  • Learn and advertise loop free paths
  • Restrict Broadcasts to the Local LAN

Networks (especially Ethernet networks) use broadcast communication at the datalinkand network layer. Network layer broadcasts are transmissions sent to all hosts using the network layer protocol (usually Internet Protocol [IP] or IPX). Network broadcastcommunication is used to communicate certain kinds of information that makes thenetwork function (ARP, RARP, DHCP, IPX-SAP broadcasts etc.). Since several devices could attempt to transmit simultaneously and cause collisions, it is preferable to separate large sets of hosts into different broadcast domains using a switch, or router.

As the number of hosts on the network increases, the amount of broadcast traffic increases. If enough broadcast traffic is present on the network, then ordinary communication across the network becomes difficult.

To reduce broadcasts, a network administrator can break up a network with a large number of hosts into two smaller networks. Broadcasts are then restricted to each network, and the router performs as the ‘default gateway’ to reach the hosts on the other networks.

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