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Network protocols / Local-area networks (LANs)


Network protocols
2.1.5 Protocol suites are collections of protocols that enable network communication between hosts. A protocol is a formal description of a set of rules and conventions that govern a particular aspect of how devices on a network communicate. Protocols determine the format, timing, sequencing, and error control in data communication. Without protocols, the computer cannot make or rebuild the stream of incoming bits from another computer into the original format.


Protocols control all aspects of data communication, which include the following:

• How the physical network is built
• How computers connect to the network
• How the data is formatted for transmission
• How that data is sent
• How to deal with errors

These network rules are created and maintained by many different organizations and committees. Included in these groups are the Institute of Electrical and Electronic Engineers (IEEE), American National Standards Institute (ANSI), Telecommunications Industry Association (TIA), Electronic Industries Alliance (EIA) and the International Telecommunications Union (ITU), formerly known as the Comité Consultatif International Téléphonique et Télégraphique (CCITT).

Local-area networks (LANs)
2.1.6 LANs consist of the following components:


• Computers
• Network interface cards
• Peripheral devices
• Networking media
• Network devices

LANs allow businesses to locally share computer files and printers efficiently and make internal communications possible. A good example of this technology is e-mail. LANs manage data, local communications, and computing equipment.

Some common LAN technologies include the following:

• Ethernet
• Token Ring
• FDDI


WANs interconnect LANs, which then provide access to computers or file servers in other locations. Because WANs connect user networks over a large geographical area, they make it possible for businesses to communicate across great distances. WANs allow computers, printers, and other devices on a LAN to be shared with distant locations. WANs provide instant communications across large geographic areas.


Collaboration software provides access to real-time information and resources and allows meetings to be held remotely. WANs have created a new class of workers called telecommuters. These people never have to leave their homes to go to work.

WANs are designed to do the following:

• Operate over a large and geographically separated area

• Allow users to have real-time communication capabilities with other users

• Provide full-time remote resources connected to local services

• Provide e-mail, Internet, file transfer, and e-commerce services

Some common WAN technologies include the following:

• Modems

• Integrated Services Digital Network (ISDN)

• Digital subscriber line (DSL)

• Frame Relay

• T1, E1, T3, and E3

• Synchronous Optical Network (SONET)

The next page will introduce metropolitan-area networks (MANs).

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