Routing is the process of taking a packet from one network device, sending it through the network to another device in a different network. Communications across the Internet is one of the best examples of routing.
The connection of WANs and LANs to a network router and configuring it with logical network addresses (IP address) to all the host on the internetwork to enable communication across the network is a form of routing.
To enable routing between inter-networks, you need a router. If your network have no router it means you not routing and cannot deliver a packet from one inter-network to another.
Routers are generally known as intermediate systems, which operates at the network layer of the OSI reference model, routers are devices used to connects two or more networks (IP networks) or a LAN to the Internet.
The router is responsible for the delivery of packets across different networks. The destination of the IP packet might be a web server in another country or an e-mail server on the local area network. It is the responsibility of the router to deliver those packets in a timely manner. The effectiveness of internetwork communications depends on the ability of routers to forward packets in the most efficient way possible.
Routers are now being added to satellites in space. These routers will have the ability to route IP traffic between satellites in space in much the same way that packets are moved on Earth, thereby reducing delays and offering greater networking flexibility.
Advantages of a Router
In addition to packet forwarding, a router provides other services as well. To meet the demands on today’s networks, routers are also used :
i. To ensure steady, reliance availability of network connectivity. Routers use alternative parts in the case the primary part fails to the delivery of packets.
ii. To provide integrated services of data, video, and voice over wired and wireless networks.
For security, router helps in mitigating the impact of worms, viruses, and other attacks on the network by permitting or denying the forwarding of packets.