Wednesday, October 5, 2011

What Is Ethernet ?

We have covered all important topics in computer network section regarding Computer networking, writing about Ethernet with context to all the topics in this section will help enhance and clear the understanding to even better levels. In this particular section, we will explain terminologies of LAN, overview of basic Ethernet networking, introduction to IEEE, Wan Standards etc. You can review other important related topics of computer networks by going to main computer network section.

If you know little bit of Computer networks, I am sure you will be familiar with IEEE standards, this is Institute of Electrical and Electronic Engineers developed by International Standard Organization (ISO) in 1985. IEEE developed LAN standards, which is commonly known as IEEE 802 standards. These are set of standards which are widely adopted by IT sector through out the world. Most commonly known and popular standards of IEEE are IEEE 802.3 which is known as Ethernet. Ethernet is LAN technology used world wide on very large scale, almost every office, school and even homes have deployed Ethernet technology. Xerox corporation developed LAN in 1972 which was world first LAN as well. All the hardware manufactures uses set of Standards by ISO to produce products which can operate any where in the world.
The Ethernet in its simplest form uses a passive bus that operates at 10 Mbps. The bus is formed from the co-axial cable, which connects all the PCs in the LAN. LAN is widely used computer network type world wide, it can practically hold up 1024 computers attached to a single LAN. Although we do not see this many computers connected to LAN, far lesser numbers of computers are used in LAN depending on the size of the organization and computer requirements.
Time has changed dramatically now, It is all about time and reliability now, time is the most vital factor when it comes to send, receive and share information securely. Distance has increased from just a building to thousands of miles, data is sent, received and shared among this distance in seconds now, same data can be shared from miles simultaneously, nature of the data can be voice, video etc, which moves from remote location in fraction of seconds. This all happens because of Internet, which allows businesses from remote location to share information with their customers to other part of the world.
In today’s IT world the reliable and timely access to the information has become vital. Today coworkers thousands of miles apart from each other can share data, voice, video etc with the fractions of seconds. Similarly a larger number of the coworkers can review the research data simultaneously. The Internet allows businesses to share information and resources with their customers. Ethernet is communication protocol for all majority networks; this protocol is embedded in hardware devices and software. Ethernet has become the standard protocol of computer networking with help of companies like Intel, Xerox and Digital.
Components of LAN

LAN consists of the following components.

a) Number of Computers, 2 or more
b) NIC, network interface cards in every computer
c) Ethernet Cable Cat5, STP/UTP
d) Router, and Hub or switch
e) Computer network software.
LAN card which is also called Network interface card is installed in every individual computer which is to be included in network, each Nic is assigned unique address for unique identification. Two computers are connected with communication medium Ethernet Cable, cable has RJ45 connectors at the both ends of the cable. Either two computers are directly attached to each other or each computer is directly connected with hub/switch which enable networked computers to communicate with each other. Switch and hubs works as relay.

In same way the entire computer network can be setup wirelessly, instead of using cable, radio signals are used for communication, Wireless LAN cards are used instead of simple LAN cards. A small antenna is used in wireless network cards which send and receive radio signals from other computers or wireless hubs, wireless switches and wireless routers. Wireless LAN is very easy to set up, it keeps the environment rather clean and organized, however more configuration is required to keep up the wireless network perform flawlessly. Wireless LAN is also know as Wi-Fi, We have covered Wi-Fi topic in details.

Wireless LAN is alternative technology to Ethernet; Token ring topology is another alternative technology to Ethernet. IBM and ATM have designed Token Ring. Using ATM technology, devices are connected with each other over very large distance; which become possible due to Wireless LAN. Ethernet is established network standards and supports both small and medium sized networks. It is in for past 3 decades and have formed excellent communication environment. Ethernet follows some rules and before we go to rules some terminologies are important to enough to be read about.

a) Node – The devices that are attached to the segments are nodes.
b) Frame – Frames are short messages which are sent by nodes (computer and network devices). Frames are basically chunk of information which size varies.
c) Segment – A single shared medium is known as Ethernet segment.
d) Medium – The Ethernet devices are attached to a common communication medium. The frames of the data travel along with that medium. This medium can be coaxial cable. Most commonly used communication mediums are UTP/STP cable, fiber optic cables.

Ethernet Set of Rules

Ethernet has specific set of rules for generating frames.
• Length of frame Varies
• Frame must contain source of message and destination address for identification
• Nodes should be uniquely identifiable
• Unique Address for each Ethernet device

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