DATA COMMUNICATIONS AND NETWORKING II


Wide Area Networks | Internet | Electronic Data Interchange (EDI) and Electronic Commerce


NOTE: These notes are prepared exclusively for the benefit of the students at the State University of New York at Albany. They are not to be used by others without the permission of J. Gangolly.


Wide Area Network

A wide-area network ia a computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs). Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet. (From PCWebopaedia.)

The main difference between Local Area Networks (LANs) and Wide Area Networks (WANs) is in the distance over which communication is provided. Unlike LANs, WANs do NOT limit the distance spanned by the network. A good exampole is the internet itself -- a good example of a WAN.

In a LAN, each computer on the network has a network interface card (NIC), usually the ethernet card, which connects the computer directly to the network medium (thick/thin ethernet wire or 1o Base T wire). On the otherhand, in WANs, the network consists of a series of complex computers, called packet switches interconnected by communication lines & modems; a computer is attached to the WAN by connecting it to one of the packet switches.

WANs usually operate at slower speeds (56Kbps to 155 Mbps) and have significant delays, compared with LANs which operate at higher speeds (10Mbps to 2Gbps) and have significantly lower delays.

WANs can be either public or private.

Private WAN:

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Internet

Internet is a global web connecting more than a million computers. Currently, the Internet has more than 30 million users worldwide, and that number is growing rapidly. More than 100 countries are linked into exchanges of data, news and opinions. (From PCWebopaedia.)

Intranets & Extranets.


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Electronic Data Interchange & Electronic Commerce

the transfer of data beween different companies using networks, such as the Internet. As more and more companies get connected to the Internet, EDI is becoming increasingly important as an easy mechanism for companies to buy, sell, and trade information. ANSI has approved a set of EDI standards known as the X12 standards. (From PCWebopaedia. )



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Updated on September 24, 1997 by Jagdish S. Gangolly.