Aditya Abeysinghe Networking

We discussed about switches in a previous post and this post will explain you about routers. In this article : 1. Routers vs Switches 2. Use of routing tables 3. How data packets are transferred by a router Routers vs Switches Consider the following two networks. Fig 1 : Network at the start Suppose you want to connect the computers in the first network together, you could use a switch for that purpose. Same thing could be done with the second network. However, if you want to communicate from one of the computers in the first network with that of a second network, can you just use switches? The answer is no. This is where routers come in to play. Use of routers for such connections serves many purposes. But most importantly, routers enable you to connect to all sorts of networks like local area networks (LANs), metropolitan area networks (MANs) or even wide area networks (WANs, such as the Internet). For example, assume the first network in some part of Asi...

In simple terms, both hubs and switches are used to connect devices, as shown below. However, hubs work differently from switches in their operations (that is in how they send packets).  How does a hub work? When a hub is connected as shown above to all computers, then data is broadcast to all the devices connected. For example, consider the diagram below. Suppose that computer A needs to send data to computer C.  Then it first sends data to the hub, where all the devices are connected, and then the hub will send this data to all the devices. Simply, a hub does not filter the addresses and sends a packet it receives to all the devices connected to it as shown below. Every computer checks the destination address of the packet and if the destination address of the packet match with that of the computer, the packet is accepted. Therefore, this is not an efficient approach of exchanging data. Furthermore, this nature of data sharing le...