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What are Routers, Switches, Hubs — Is There a Difference between them ?

ashish — Wed, 01 Jul 2009 14:23:59 +0000

Each device has its own function in a network environment. Two reasons confusion exists are
(1) all three are simple boxes with several plugs that accept cables and
(2) at times the functions of each device are rolled into one single device.

A hub, also known as a repeater, is a simple device used for years to connect all nodes, or computers, on a network to a central location. Each node on a network has a unique hardware address called a MAC address. A hub is known as a repeater because when a packet of data, or frame, is sent through the hub, it is repeated to each and every computer on the network.

A switch-based network is one that utilizes switches instead of hubs. A switch is a major upgrade to a hub. Instead of sending all network data to each and every network node, the switch will analyze the MAC address and determine where to send the data. Network bandwidth is not wasted by sending every frame to every port.

Routers not only provide connections to the internet, they also protect the LAN from the Internet. The router could block any Packet that has a destination address outside of the LAN. In short, a router can perform many of the same functions as switches and hubs, but it has address translation and filtering capabilities.

Quick description – How does a Router work?

ashish — Wed, 01 Jul 2009 14:20:45 +0000

Here is a technical description of how a router works. This would make sense if you have already an understanding of the network protocols.
The layers 2 and 3 of the OSI model i.e. Data Link layer, is where the Ethernet protocol, MAC addresses and switches fit in.
Layer 3, the Network layer, is where the IP protocol, IP addresses and routers fit in. All traffic is sent from your computer, starting with Layer 7 (your network application) and going down to Layer 1 (physical). With the physical layer, the traffic is going across your network medium.
Traffic goes to a router only if it is not on your local LAN. Routers work primarily at Layer 3 but must understand Layers 1-3, at a minimum. Many routers understand traffic all the way up to Layers 4-7 in varying ways.
One of the tools a router uses to decide where a packet should go is a configuration table. A configuration table is a collection of information, including:
• Information on which connections lead to particular groups of addresses
• Priorities for connections to be used
• Rules for handling both routine and special cases of traffic
Internet data, whether in the form of a Web page, a downloaded file or an e-mail message, travels over a system known as a packet-switching network. In this system, the data in a message or file is broken up into packages about 1,500 bytes long which includes information on the sender’s address, the receiver’s address, the package’s place in the entire message, and how the receiving computer can be sure that the package arrived intact. Each data package, called a packet, is then sent off to its destination via the best available route — a route that might be taken by all the other packets in the message or by none of the other packets in the message.

Introduction to Routers

ashish — Tue, 30 Jun 2009 18:23:39 +0000

A computer networking device which forwards data packets across a network toward their destinations, through a process of routing is known as Router. In companies and large corporations, a central computer system acts as a router to connect all of the company’s computers to one network. This allows group participation and collaboration on large projects or just to connect all of the company’s resources at one central location. It also aids in reliable communication between employees working on different floors in the building or in different countries.

1. Router is required to connect multiple networks, like your LAN to the Internet.
2. Routers store large tables of networks and addresses, then using algorithms to determine the shortest routes to individual addresses within those networks.
3. Routers not only facilitate intra-network communications, but also play a role in overall network performance.
4. Routers help in delivering the information faster.
5. Routers also protect LAN from Internet.
6. Router blocks any packet that has a destination address outside of the LAN. If the destination address is valid, the router could check the Packet for an error. If there is an error, the router could discard the Packet and send a message to the originating address.
7. Routers have address translation and filtering capabilities.