2.1.2+Networks

= = ===**2.1.2 Networks edited by Macaulay Jape **===

Definition A **computer network** is a group of computers that are connected to each other for the purpose of communication. Networks may be classified according to a wide variety of characteristics. This article provides a general overview of some types and categories and also presents the basic components of a network.

Students must study and evaluate the social and ethical issues involved in the use of networks. These may include: - Vulnerability of networks to intrusion - Ability to implement different levels of access - Implications of network failure, for example, banks, transportation, hospitals, schools - Implications of collaboration, groupware and data sharing - Threat of compromising data integrity in shared databases - Additional threats to privacy on a network compared with stand-alone computers - The need to authenticate information - Intellectual property protection on networks, for example, site licences, file access - Equality of access for different groups and individuals - Ability to monitor users (surveillance); concerns of people regarding monitoring - Ability to filter incoming data - Ability to control personal, business, military, government operations over a wide geographical area - Increased globalization, for example, EFT, EDI, e-commerce - Need for interface standards - Need for network use policy
 * // Social and ethical issues //**

**Syllabus details** In order to study and evaluate the social and ethical issues involved in the use of networks the student must have an understanding of related technological concepts. These may include:
 * // Knowledge of technology //**

- Key terms—LAN, WAN, client, server, Ethernet, access, access permissions, login, password, firewall, sysadmin, UPS, EDI

- Types of intrusion, for example, viruses, hacking, phreaking

- Security measures

- Network types, for example, Intranet, Internet, VPN

- Encryption and SSL

- E-commerce

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** Chapter 8 Key of Terms from Computer Confluence **

**Analog signal:** A continuous wave.


 * Asynchronous communication:** Delayed communication, such as that used for newsgroups and mailing lists, where the sender and the recipients don't have to be logged in at the same time.


 * Attachments:** A way to send formatted word processor documents, pictures, and other multimedia files via email.


 * Bandwidth:** The quantity of information that can be transmitted through a communication medium in a given amount of time.


 * bits per second (bps):** The standard unit of measure for modem speed.


 * Bluetooth:** A type of wireless technology that enables mobile phones, handheld computers, and PCs to communicate with each other regardless of operating system.


 * Bounce:** The automatic return of an undeliverable email message to its sender.


 * Bridges:** Hardware devices that can pass messages between networks.


 * Chat room:** Public real-time teleconference.


 * Client/server model:** For a local-area network, a hierarchical model in which one or more computers act as dedicated servers and all the remaining computers act as clients. The server fills requests from clients for data and other resources.


 * Communication software:** Software that enables computers to interact with each other over a phone line or other network.


 * Digital signal:** A stream of bits.


 * Direct connection:** A dedicated, direct connection to the Internet through a LAN, with the computer having its own IP address.


 * Download:** To copy software from an online source to a local computer.


 * Electronic mail (email):** Allows Internet users to send mail messages, data files, and software programs to other Internet users and to users of most commercial networks and online services.


 * Ethernet:** A popular networking architecture developed in 1976 at Xerox.


 * FAQs (frequently asked questions):** Posted lists of common queries and their answers.


 * Fiber-Optic cable:** High-capacity cable that uses light waves to carry information at blinding speeds.


 * File server:** In a LAN, a computer used as a storehouse for software and data that are shared by several users.


 * Gateways:** Computers connected to two networks that translate communication protocols and transfer information between the two.


 * Global Positioning System (GPS):** A Defense Department system with 24 satellites that can pinpoint any location on the Earth.


 * Host system:** A computer that provides services to multiple users.


 * Instant Messaging (IM):** A technology that enables users to create buddy lists, check for buddies who are logged in, and exchange typed messages and files with those who are.


 * Internet telephony (IP telephony):** A combination of software and hardware technology that enables the Internet to, in effect, serve as a telephone network. Internet telephony systems can use standard telephones, computers, or both to send and receive voice messages.


 * Local Area Network (LAN):** Multiple personal computers connected on a network.


 * Mailing lists:** Email discussion groups on special-interest topics. All subscribers receive messages sent to the group's mailing address.


 * Modem:** Modulator/demodulator. A hardware device that connects a computer to a telephone line.


 * Netiquette:** Rules of etiquette that apply to Internet communication.


 * Network interface card (NIC):** Card that adds an additional serial port to a computer. The port is especially designed for a direct network connection.


 * Network license:** License for multiple copies or removing restrictions on software copying and use at a network site.


 * Network Operating System (NOS):** Server operating system software for a local-area network.


 * Newsgroups:** Ongoing public discussions on a particular subject consisting of notes written to a central Internet site and redistributed through a worldwide newsgroup network called Usenet. You can check into and out of them whenever you want; all messages are posted on virtual bulletin boards for anyone to read anytime.


 * Peer-to-peer Model:** A LAN model that allows every computer on the network to be both client and server.


 * Port:** Socket that allows information to pass in and out.


 * Protocol:** A set of rules for the exchange of data between a terminal and a computer or between two computers.


 * Real-time Communication:** Internet communication that enables you to communicate with other users who are logged on at the same time.


 * Remote Access:** Network access via phone line, TV cable system, or wireless link.


 * Routers:** Programs or devices that decide how to route Internet transmissions.


 * Server:** A computer especially designed to provide software and other resources to other computers over a network.


 * Site License:** License for multiple copies or removing restrictions on software copying and use at a network site.


 * Spam:** Internet junk mail.


 * TCP/IP (Transmission Control Protocol/Internet Protocol):** Protocols developed as an experiment in internetworking, now the language of the Internet, allowing cross-network communication for almost every type of computer and network.


 * Telecommunication:** Long-distance electronic communication in a variety of forms.


 * Telephony:** Technology that enables computers to serve as speakerphones, answering machines, and complete voice mail systems.


 * Terminal Emulation Software:** Software that allows a PC to act as a dumb terminal-an input/output device that enables the user to send commands to and view information on the host computer.


 * Upload:** To post software or documents to an online source so they're available for others.


 * Video Teleconference:** Face-to-face communication over long distances using video and computer technology.


 * Voicemail:** A telephone-based messaging system with many of the features of an email system.


 * Wide Area Network (WAN):** A network that extends over a long distance. Each network site is a node on the network.

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 * Wi-Fi:** A popular wireless LAN technology that allows multiple computers to connect to a LAN through a base station up to 150 feet away. Often referred to as 802.11b
 * Wireless network:** A network in which a node has a tiny radio or infrared transmitter connected to its network port so it can send and receive data through the air rather than through cables.