Computer Network Overview

Computer networking or data communication is a most important part of the information technology. Today every business in the world needs a computer network for smooth operations, flexibly, instant communication and data access. Just imagine if there is no network communication in the university campuses, hospitals, multinational organizations and educational institutes then how difficult are to communicate with each other. In this article you will learn the basic overview of a computer network. The targeted audience of this article is the people who want to know about the network communication system, network standards and types.

A computer network is comprised of connectivity devices and components. To share data and resources between two or more computers is known as networking. There are different types of a computer network such as LAN, MAN, WAN and wireless network. The key devices involved that make the infrastructure of a computer network are Hub, Switch, Router, Modem, Access point, LAN card and network cables.

LAN stands for local area network and a network in a room, in a building or a network over small distance is known as a LAN. MAN stands for Metropolitan area network and it covers the networking between two offices within the city. WAN stands for wide area network and it cover the networking between two or more computers between two cities, two countries or two continents.

There are different topologies of a computer network. A topology defines the physical layout or a design of a network. These topologies are star topology, bus topology, mesh topology, star bus topology etc. In a star topology each computer in a network is directly connected with a centralized device known as hub or switch. If any computer gets problematic in star topology then it does not affect the other computers in a network.

There are different standards and devices in computer network. The most commonly used standard for a local area network is Ethernet. Key devices in a computer network are hub, switch, router, modem and access point etc. A router is used to connect two logically and physical different networks. All the communication on the internet is based on the router. Hub/Switch is used to connect the computers in local area network.

Hopefully, in this article you may have learnt that what a computer network is, how important it is in our lives, what are different network devices, standards, topologies and communication types.

B. Bashir manages this website Networking Tutorials and regularly writes articles on various topics such as Computer Networking, Network Troubleshooting Tips Wireless Networking, Computer Hardware, Certifications, How Tos, Network Security Guide and computer tips.

An Overview Of Computer Networks

My second degree, or should I say my second go through inside the education system was in networking. I'm a certified Novell and Microsoft engineer, not that I'm all that excited about the fact. Networking is actually pretty mindless work once you learn it. It's pretty much do it by the numbers based on what the customer wants. After you hook everything up the software installation is pretty straight forward. My 16 year old daughter could do it or as GEICO would say, a caveman could do it.

In this article I'm just going to cover the basics of what a network is and the types of networks. I'll go into more detail in later articles.

A network is simply a means for computers to speak to each other, or communicate with each other. With a network, computers can receive emails from each other, send files to each other, instant message each other and a variety of other things. This is something that we take for granted today but there was a time when networks were not so sophisticated and not all that efficient either.

There are basically two types of networks.

The simplest network is a LAN or Local Area Network. This is where all the computers in the network are located in one place such as an office building. Within this type of network you have 2 ways to connect.

The simplest way is peer to peer. This is where 2 or more computers are hooked up directly to each other. In other words if you have 5 computers you would have computer 1 hooked into computer 2 which would be hooked into computer 3 and so on. In this type of connection each computer is dependent on the other. So if computer 3 would go down then computers 1 and 2 would not be able to communicate or exchange information with computers 4 and 5 and visa versa. That is the main problem with a peer to peer network. Also in peer to peer networks the write process between computers leads to data corruption problems. This is not something they teach you in school but something you learn from experience.

The more common type of LAN connection is client server. This is where all the computers in the network are connected to each other via a central computer. This kind of connection does require more work in set up but is more efficient, carries data better and if one computer goes down the others aren't affected. However, should the server go down then all the computers on the network would be affected as far as their ability to get information from the other computers and the server itself. They, however, would still be able to do work locally on their own such as with a word processing program, unless the word processing program was located on the server. Then it would not be available. Usually, however, most applications are installed on each computer. What is most commonly lost when a server goes down is the ability to retrieve data that is common to everyone in the network, say an in house database of all employees.

The second type of network is a WAN or wide area network. This is where several LAN networks or even single computers are connected to a much larger network. A perfect example of a WAN is the Internet. This is where users from all over the world can interact with each other through email, chat rooms and instant messaging. WANs are enormous to say the least and are very intricate in their design, requiring hubs from all over the world to stay connected. One hub goes down and it can affect connections for millions of people though there are protocols instituted to reroute connections if a hub does go down.

The above is a very simplified overview of computer networks. In future articles I'll go into detail on the hardware and software required to set up these networks and some of the finer points. Stay tuned.

Michael Russell

Your Independent guide to Networking [http://networking.for-home-and-office.com/]

An Overview of the Computer Network Devices & Components

A Computer network is comprised of different devices to share, transmit, and boost the signal, voice and data. Network devices or components are the physical parts connected to a network. There is a large number of the network devices and are increasing daily. The basic network devices are: Individual Computers, Server, Hub, Switch, Bridges, Routers, Modems, Printers, DSL Modems & Routers, Gateways, Network Interface Cards, Cabling & Wireless access point. The following is a overview of each of these network devices.

INDIVIDUAL COMPUTERS: The personal computer is usually a desktop computer, a work station or a laptop. The personal computers are most widely used in any organization or for personal use. The individual computers are the most common types of the microcomputers.

SERVER: A server is a computer on a network, which process request and is used to share the data and resources among the other computers in a network. A server stores all the necessary information and provides the different services like, workstation computer's logon access, internet sharing, print sharing, disk space sharing etc. There are different types of servers e.g File and print server, database server, proxy server, Fax server, backup server etc. A database server stores all the data and software, which may related to the certain database and it allows other network devices to access and process the database queries. A file server is used to store the data of any user on the network and a print server manages one or more printers in a network. Similarly a network server is a server that manages the network traffic.

NETWORK INTERFACE CARD: Network interface cards are attached with the computer or other network devices and are used to provide the connectivity between the two computers. Each network card is specifically designed for the different types of the network like Ethernet, FDDI, Token Ring and Wireless Networks. The Network card operates on the first and second layers of the OSI models i.e Physical layer and datalink layer specifications. NIC basically defines the physical connection methods and the control signals that provides the timings of the data transfer over the network.

HUBS: Hub is a simplest network device. The function of the hub is broadcasting i.e data is forwarded towards the all ports of a hub, regardless of whether the data was intended for the particular systems in the network or not. Computers in a network are connected to a hub with a twisted pair (CAT5) cables. There are two types of the hubs. 1. Active Hubs. 2. Passive Hubs.

SWITCHING HUB: The Switching hub (also called "switch" is the most advance shape of the basic hub. In a basic hub all the computers are connected with the hub and the speed of the network is defined by the slowest computer network card connected. For example if you have 10/100 Mbps cards in a network and only one card of 10Mbps speed then the system cannot run faster than the 10 Mbps. Now if you have a switching hub in a network, it will allow all the faster connections in the network to remain at the higher speed and still interact with the 10Mbps system.

SWITCHES: Switch is a intelligence device than hub. Switch is a layer 2 device. Swith provides the same function as a hub or a bridge but it has the advance functionality of connecting the two computers together temporarily. Switch contains the switch matrix or switch fabric that can connect and disconnect ports. Unlike hubs, switch only transmit or forwards the data to the destined computer and it does not broadcasts the data to all its ports.

MODEMS: Modems are the devices, which are used to translate the digital data into the analog format and vice versa. It performs the two main functions. Modulation and demodulation. A modulated data can travel across the conventional telephone lines. The modem modulates the signals at the sending end and demodulates at the receiving end. Modems are required for different types of the access methods such ISDN, DSL and 56K data modem. Modem can be the internal devices that plug into the expansion slots in a system or can be external devices that plug into the serial or USB ports. In Laptops, PCMCIA cards are used for this purpose and many new laptops having the built in integrated modems. The specialized devices are designed for use in the systems such as handheld computers. In ISPs where the large scaled modems are required, rack-mounted modems are used.

ROUTERS: Routers route the data between two logically and physically different networks. A Router has the capability to determine the destination address for the data and hence provides the best way for the data to continue its journey. Router gets this capability through its software called routing software. Unlike Switches and Bridges, which use hardware configured MAC address to determine the destination of the data, router uses logical network address such as IP address to make the decision in determining the destination of the data.

GATEWAY: A gateway performs the function of translating the data from one format to another format without changing the data itself. A gateway can be a device, system, software. A computer with two NIC cards can function as a gateway. Router acts as a gateway e.g a router that routes the data from a IPX network to a IP network is technically a gateway. The same can be said of translational switch converts from a Ethernet network to a token ring network.

CABLES: There are two most common types of the cables. 1. 10baseT and 10base2. 10baseT is a four paired cable. 10baseT has further two types 1. UTP (unshielded twisted pair) and 2. STP (shielded twisted pair. STP is most secure cable covered with the silver coated twisted paper to protect the cable. On the other end Thin 10base2 looks like the copper coaxial cabling that often used to connect TV sets and VCR. 10baseT/Cat5 cables are most commonly used cables to connect the computers. It has the connector, (like a telephone connector) called RJ45 connector.

Twisted pair cables are ideal for the small, medium or large networks.

My recommendation for using cables for networking is to use 10baset/Cat5 cables

Submitted by:

Fiza
http://www.theitlibrary.com