1. Networks and networking
A network is an intricately connected system of objects or people. Networks are all around us, even inside us. Your own nervous system and cardiovascular system are networks. The cluster diagram in the figure shows several types of networks; you may think of others.Notice the groupings:
2. Data networksData networks came about as a result of computer applications that had been written for businesses. . However, at the time when these applications were written, businesses owned computers that were standalone devices and each one operated on its own, independent from any other computers. Therefore, it became apparent that this was not an efficient or cost effective manner in which to operate businesses.
They needed a solution that would successfully address the following three questions:
1. how to avoid duplication of equipment and resources
2. how to to communicate efficiently
3. how to set up and manage a network
Businesses recognized how much money they could save and how much productivity they could gain by using networking technology. They started adding networks and expanding existing networks almost as rapidly as new network technologies and products were introduced. As a result, the early 1980s saw a tremendous expansion in networking and however, the early development of networks was chaotic in many ways.
By the mid-1980s, growing pains were felt. Many of the network technologies that had emerged had been created with a variety of different hardware and software implementations. Consequently, many of the new network technologies were incompatible with each other. It became increasingly difficult for networks that used different specifications to communicate with each other.
One early solution to these problems was the creation of local area networks (LANs). Because they could connect all of the workstations, peripherals, terminals, and other devices in a single building, LANs made it possible for businesses using computer technology to efficiently share such things as files and printers.
As the use of computers in businesses grew, it soon became obvious that even LANs were not sufficient. In a LAN system, each department or company is a kind of electronic island.
What was needed was a way for information to move efficiently and quickly, not only within a company, but from one business to another. The solution, then, was the creation of the metropolitan area networks (MANs) and wide area networks (WANs). Because WANs could connect user networks over large geographic areas, they made it possible for businesses to communicate with each other across great distances.
3. Data Networking SolutionsFor your studies, most data networks are classified as either local area networks (LANs) or wide area networks (WANs). LANs are usually located in single buildings or campuses, and handle interoffice communications. WANs cover a large geographical area, and connect cities and countries. Several useful examples of LANs and WANs appear in the figure; these examples should be referred back to whenever there’s a question about what constitutes a LAN or WAN. LANs and/or WANs can also be linked by internetworking.
|0.1 m||Printed Circuit board.||Motherboard|
|1.0 m||Milimeter||Computer System Network|
|10 m||Room||Local Area Network|
|100 m||Building||Local Arena Network|
|1 km||Campus||Local Arena Network|
|100 km||Country||Wide Area Network|
|1,000 km||Continent||Wide Area Network|
|10,000 km||Planet||Wide Area Network|
|100,000 km||Eart-moon Syatem||Wide Area Network|
4. Local area networksOne early solution to these problems was the creation of local area networks (LANs). Because they could connect all of the workstations, peripherals, terminals, and other devices in a single building, LANs made it possible for businesses using computer technology to efficiently share such things as files and printers.
Local area networks (LANs) consist of computers, network interface cards, networking media, network traffic control devices, and peripheral devices. LANs make it possible for businesses that use computer technology to share, efficiently, such items as files and printers, and to make possible communications such as e-mail. They tie together: data, communications, computing, and file servers.
LANs are designed to do the following:
* operate within a limited geographic area
* allow many users to access high-bandwidth media
* provide full-time connectivity to local services
* connect physically adjacent devices
There are many online resources for gaining the most recent information on LANs. Take a moment to browse some of these sites.
* Communications Week
* Data Communications
* Network Magazine
* LAN Times
* Network Computing
5. Wide area networksAs computer use in businesses grew, it soon became apparent that even LANs were not sufficient. In a LAN system, each department, or business was a kind of electronic island. What was needed was a way for information to move efficiently and quickly from one business to another.
The solution was the creation of wide area networks (WANs). WANs interconnected LANs, which then provided access to computers or file servers in other locations. Because WANs connected user networks over a large geographical area, they made it possible for businesses to communicate with each other across great distances. As a result of being networked or connected, computers, printers, and other devices on a WAN could communicate with each other to share information and resources, as well as to access the Internet.