Router – What is a router?

What is Router and what is he doing?

Router is the device that has the ability to route packets. In other words, primary responsibility of router is to find the best way for a packet to arrive at his destination network and forward packets from one network to the next one through this selected path. Devices on different networks would not be able to communicate if there is no router between those networks.

Routers are hidden but they are always working for us

Typical users are unaware of all the routers in their network environment or on the Internet. Users are expecting to send e-mails, browse web pages and download data and they are not really interested where is this data stored. They don’t ask if the server that they are accessing is on their local network or is on some other remote network.

How is Router doing his job?

A router connects multiple networks in the way that it has multiple interfaces that each belongs to a different network. When a packet comes into the router on one interface, router determines which interface is the best for forwarding the packet onto its destination. This interface that the router uses to forward the packet can be the interface in the final destination of the packet or a way to next router that is the best way to reach the destination network.

Each network that a router connects to needs a separate interface. Interfaces are used to connect to Local Area Networks – LAN or Wide Area Networks – WAN. LANs are commonly Ethernet networks that contain devices such as PCs, printers, and servers. WANs are used to connect networks over a large geographical area.

What else are they doing?

Router has additional services as well and not only packet forwarding function. All of these services are built around the routers main function.

Modern routers have the ability to:

  • Ensure continuous around-the-clock availability.
  • Guaranteed network reachability by use of alternate paths in case the primary path fails.
  • Integrated services of voice, data and video over all kinds of wired and wireless networks. This is made possible by use of Quality of service (QoS) prioritization of IP packets to ensure that real-time traffic, such as voice; video and critical data are not delayed.
  • Integrate some firewall abilities and in that way fight against worms, viruses, and other attacks on the network by permitting or denying the forwarding of packets.

Networks today are used in a variety of ways, including IP telephony, gaming, web applications, commerce, education, and etc. The center of the network is the place where the router stands. Router’s job is to connect one network to some other network. We can say that the Router is responsible for the delivery of packets across different networks. IP packet might be sent to some web server or mail server in another part of the world and the routers are responsible for efficient delivery of all those packets.



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