Networking Hardware

Cabling :
Cable is the medium that ordinarily connects network devices. Network users have three basic cable choices : coaxial, twisted-pair and fiber-optic. Coaxial and twisted pair cables both use copper wire to conduct the signals, fibre-optic cable uses a glass or plastic conductor. Before the Ethernet standards for unshielded twisted-pair installations were approved in 1992, the majority of LANs used coaxial cable, but a high proportion of subsequent installations have used the more flexible and less costly unshielded twisted-pair medium. the use of fiber optics in local network growing, albeit slowly. Fiber is most often used on the backbone network and is not commonly run to the desktop.
Coaxial Cable : Coaxial cable or coax, has a long history. Remember the cable television in our homes, Broadband transmission uses the same principles as cable TV and runs on coax. Broadband and cable TV takes advantage of coaxial cables ability to transmit many signals at the same time. Each signal is called a channel. Each channel travels along at a different frequency, so it does not interfere with other channels. Coaxial cable provides a higher capacity than the copper or twisted-pair cables. Coax cable has four parts. The inner conductor is a solid metal wire surrounded by insulation. A thin, tubular piece of metal screen surrounds the insulation. Its axis of curvature coincides with that of the inner conductor, hence the name coaxial. Finally an outer plastic cover surrounds the rest.
Coax comes in two sizes. Thick Ethernet and Thin Ethernet. Thicker coax is more robust, harder to damage and transmits data over longer distances. It's also more difficult to connect.
Thin Ethernet uses a biconic ( or BNC) connector which is easer to install.

Modern Benefits of Networking

1. Data Sharing :
Sharing data today is easier than ever, thanks to networking. E-mail has become one of the leading motivators for companies to invest in networks. Shared files may exist in one location with multiple accessing them or updating parts of them. Not only data files may be shared, but executable files may be shared as well. When user invokes an executable file on a network server, a copy of it is transmitted over the network into the memory of the local user's workstation.

2. Resource Sharing :
One of the distinct benefits of modern networking is the ability to share peripherals. Few companies have the available resources to place a printer on every user's desk. Networks offer a logical and cost-effective solution. Since, once again the introduction of several users could cause conflict at the printer, spooling is utilized so that print jobs can be arranged in an orderly manner. NetWare privides such services in the form of print queues and print servers.

Introduction to Modern Networking

The ability to balance processing load and resources was the prime motivator for moving towards the modern era of networking. The U.S. government had discovered the necessity of spreading out loads of information on its numerous computers. Department of Defense, a move to create a network linking the government's vast computer resources was undertaken. This expensive network as called ARPANET (Advanced Research Projects Agency Network).
Important about the development of ARAPNET was the creation of protocols for linking dissimilar computers together. The evolution of these successes in interoperability lead to the development of a very dominant set of protocols (called a suite) called TCP / IP protocols (Transmission Control Protocol / Internet Protocol). The huge internetwork that sprang from ARPANET is now called Internet.
In the late 70s, DEC, Intel and Xerox developed a scheme for networking across multi-vendor platforms. This new type of localized network, called Ethernet. Ethernet governs the physical aspects of interconnecting local computers such as the cabling type, allowable distance, how data is placed on the wire, how the data is formatted, etc. Because of these characteristics, Ethernet is often referred to as a "media" protocol. Ethernet is still in use today, in the PC network era, offering speeds of data transfer up to 10 million bits per second (Mbps).
The ability to link computers, often those created by different vendors, is made feasible by the adoption of standards. Standards-setting organizations include the International Organization for Standardization (formerly the International Standards Organization or ISO) and the Institute of Electrical and Electronic Engineers (or IEEE).
The growth of modern networking will continue on its rapid curve for quite some time as technology continues to develop. Networks will continue to grow in both size and complexity. From their humble beginnings to the colossal systems of today, networks have evolved into an integral and necessary part of the corporate world.

Computer Network - Use of Computer Networks

Use of Computer Networks

1. Networks for companies :
Many organizations have a substantial number of computers in operation, often located far apart. For example, a company with many factoires may hava a computer at each location to keep track of inventories, monitor productivity and to do the local payroll. Management may have decided to connect them to be able to extract and correlate information about the entire company.
The issue here is resource sharing and the goal is to make all programs, equipment and especially data available to anyone on the network without regard to the physical location of the resource and the user.
A second goal is to provide high reliability by having alternative sources of supply. For example all files could be replicated on two or three machines, so that if one of them is unavilable, the other copies could be sued.

• Another goal is saving money. Small computers have much better price/performance ratio than large ones.

Another networking goal is scalability, the ability to increase system performance gradually as the workload increases.
Another goal of setting up a computer network has to do with technology. A computer network can provide a powerful communication medium among widely separated employees.

2. Networks for People :

Starting in the 1990's computer network began to start delivering services to private individuals at home. These services and the motivations for using them are quite different thatn the "corporate efficiency" model.

• Access to remote information
• Person to person communication
• Interactive entertainment

Access to remote information : Access to remote information will come in many forms. Many peoples pay their bills, manage teir bank accounts and handle their investments electronically. Home shopping is also becoming popular.

Person to person communication : Electronic mail or email is widely used by millions of people and contain audio and video as well as text.

Interactive entertainment : It may possible to select any movie or television program, in any country and have it displayed on the screen instantly. Live television may also become interactive , with the audience participating in quiz shows.

COMPUTER NETWORK

Introduction to Networks

The term computer network means an interconnected collection of autonomous computers.

Computers can be linked by networks to share data and resources. Computer networking began in early 1980.

In its simplest form, a network consists of computers connected together using network interface cards (NIC), networking software and network cabling. An individual computer connected to a network is a workstation, and any individual device such as workstation, printer, scanner or fax connected to a network is a node.

The main utility of a computer networks is involved in sharing resources between users shraring of resources of common needs can help companies reduce cost.

People use different types of networks every day :

• Mail delivery system
• Telephone system
• Public transportation system
• Corporate computer network
• The Internet
  

Different types of network media:

• Copper cabling


• Fiber-optic cabling


• Wireless connection

Benefits of Networking

* Fewer peripherals needed

* Increased communication capabilities

* Avoid file duplication and corruption

* Lower cost licensing

* Centralized administration

* Conserve resources

Internet Explorer Error !!!

When internet explorer opens and view some of the sites, but open hotmail it not show anything one , done is appear at bottom of the internet explorer as like open yahoo mail , it opens all yahoo inbox items, but you should open a individual mail, then it opens but no contents of the message is appear on the screen. I tried the following commands in windows 2003 server, then the Internet Problem is solved.

Go to RUN in the start menu, then type in the following commands:
regsvr32 urlmon.dll
regsvr32 jscript.dll
regsvr32 wshom.ocx
Each should prompt a confirmation box saying it has been successful.
This should fix your problems.

After that IE works fine.