Living Online Module Lesson 23 — Networks and Telecommunication Computer Literacy BASICS

2 Objectives Describe a network. Explain the benefits of a network. List and describe the types of networks. Explain the advantages and disadvantages of networked computing. List and describe communications media.

Computer Literacy BASICS 3 Objectives (cont.) Describe communications hardware. Describe network architecture. Describe communications software.

Computer Literacy BASICS 4 Vocabulary Bridge Client Client/server network Communications channel Extranet Gateway Hub Intranet

Computer Literacy BASICS 5 Vocabulary (cont.) Modem Network interface cards (NICs) Peer-to-peer network Router Server Transmission media

Computer Literacy BASICS 6 Networks A network is a group of two or more computers linked together. Most networks have a server that manages the network resources. Most networks have multiple clients, which are computers that access the server. An endpoint of a network connection, such as a computer terminal, server, or printer, is called a node.

Computer Literacy BASICS 7

8 Networks (cont.) A network confined to a limited geographical area is called a local area network (LAN). A network spread over a wide area is called a wide area network (WAN). – Most WANs are made up of several LANs. The transmission of data from one location to another is called data communications.

Computer Literacy BASICS 9 Components Required for Data Communications A sending device, which is generally a computer A communications device, such as a modem, that converts the computer signal into signals supported by the communications channel A communications channel or path, such as telephone lines, cable, or a wireless transmission link, over which the signals are sent A receiving device that accepts the incoming signal, which is generally a computer Communications software

Computer Literacy BASICS 10 Communications Components

Computer Literacy BASICS 11 Network Benefits Networks provide almost instant communication with other users on the network. Users can share information. Users can share hardware. Users can share software. Users can work on group projects.

Computer Literacy BASICS 12 Communications Media Sending data from one computer to another requires a channel, the link through which the message is sent. – A phone line or cable serves as a channel. You also need a device on each end of the channel to convert the computer signal to a signal type that the channel can send. – A modem is a conversion device.

Computer Literacy BASICS 13 Transmission Media Sending a message through the channel requires a transmission media, which can be physical or wireless. Examples of physical media include twisted- pair cable, coaxial cable, and fiber-optic cable. Examples of wireless media include radio signals, microwave signals, and satellite transmissions.

Computer Literacy BASICS 14 Types of Physical Media Twisted-pair cable Coaxial cable Fiber-optic cable

Computer Literacy BASICS 15 Types of Wireless Media Microwave towers Satellite transmissions

Computer Literacy BASICS 16 Network Hardware Most networks consist of a server and multiple client computers. They also include two other categories of hardware: – Communications hardware to facilitate the transmitting and receiving of data – Network transmission hardware to connect the cabling and amplify signals as they travel across the network.

Computer Literacy BASICS 17 Communications Hardware A modem converts analog signals to digital and vice versa. – Modems enable a computer to send data over a standard phone line. – The sending computer and the receiving computer must both have modems. Cable modems use coaxial cable to send data over cable television lines. – These have much faster transmission rates than a standard telephone line modem.

Computer Literacy BASICS 18 Communications Hardware: A Computer with Attached Modem

Computer Literacy BASICS 19 Network Transmission Hardware Network Interface Cards (NICs): All computers in a LAN must have a NIC, which enables and controls the sending and receiving of data between the computers. Hub: Receives and sends signals back out Bridge: Connects one LAN to another LAN Gateway: Links networks using different protocols Router: Connects multiple networks and determines the fastest route for sending data over the network

Computer Literacy BASICS 20 Network Transmission Hardware HUB NIC

Computer Literacy BASICS 21 Network Transmission Hardware BRIDGE ROUTER

Computer Literacy BASICS 22 Network Transmission Hardware: Computers Connected to a Hub

Computer Literacy BASICS 23 Network Transmission Hardware: The bridge connecting two LANs

Computer Literacy BASICS 24 Network Transmission Hardware: Networks Connected by a Router

Computer Literacy BASICS 25 Local Area Networks Local area networks (LANs) are usually confined to a limited area. Most LANs connect computers and peripherals, such as printers or scanners. The two most popular LANs are – Client/server Client/server – Peer-to-peer Peer-to-peer Next

Computer Literacy BASICS 26 A Client/Server Network A computer (or more than one computer) called a server manages the network resources for all of the devices on the network. Back

Computer Literacy BASICS 27 A Peer-to-Peer Network All of the computers on a peer-to-peer network are equal— there is no server, and people on the network each deter- mine what files they will share with others on the network. Back

Computer Literacy BASICS 28 Wide Area Networks Wide area networks (WANs) cover a large geographical area such as a city, a state, a country, or the world. Most WANs consist of two or more LANs connected by routers. Two types of WANs are – Intranets – Extranets

Computer Literacy BASICS 29 Intranets An intranet is designed for the exclusive use of people within an organization. Many businesses have intranets that they use to make files, such as handbooks and employee manuals, newsletters, and employment forms, available to company employees. An intranet may use HTML files and browsers to create and view documents on the network.

Computer Literacy BASICS 30 Extranet An extranet is similar to an intranet, but it allows specified users outside of the organization to access internal information systems. Like the Internet, extranets utilize and support Web technologies, such as hyperlinks and Web pages, coded in hypertext markup language (HTML).

Computer Literacy BASICS 31 Network Operating Systems Networks require a network operating system (NOS) and a desktop operating system. The NOS runs on the server and provides – Network administration tools – Print services – Client services – Security services

Computer Literacy BASICS 32 Summary A network is a group of two or more computers linked together. A local area network is generally confined to a limited geographical area. A wide area network is made up of several connected local area networks. Data communications is the transmission of data from one location to another.

Computer Literacy BASICS 33 Summary (cont.) The Internet is the biggest network of all. You can use a network for information sharing, hardware sharing, software sharing, and as a collaborative environment. The link through which data is transmitted is the communications channel. Transmission media can be either physical or wireless.

Computer Literacy BASICS 34 Summary (cont.) Physical media includes twisted-pair cable, coaxial cable, and fiber-optic cable. Wireless media includes radio signals, microwaves, and satellite transmission. Most networks consist of a network server and computer clients. A modem is a type of communication device.

Computer Literacy BASICS 35 Summary (cont.) Network interface cards enable the sending and receiving of data between PCs in a LAN. A hub is a device that controls the incoming and forwarding of data. A bridge connects one LAN to another. A gateway links two different types of networks.

Computer Literacy BASICS 36 Summary (cont.) A router directs traffic on the Internet or on multiple connected networks. The two popular types of LANs are the client/server network and the peer-to-peer network. Networks require network operating system software.