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Computer Concepts – Illustrated Introductory, Seventh Edition UNIT E: Networks and the Internet Objectives Introduce networks Classify networks Explore network hardware Explore data transport Compare wireless and wired technology Install a LAN Computer Concepts – Illustrated Introductory, Seventh Edition Objectives Share network resources Introduce Internet technology Explore IP addresses and domain names Connect to the Internet with wires Connect to the Internet without wires Computer Concepts – Illustrated Introductory, Seventh Edition Objectives Talking points: Why pay for Internet access if you can get it for free? Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Communications network combination of hardware, software, and connecting links that transport data Allow users to share resources – hardware, software, and data Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Ethernet Significant network idea conceived by Bob Metcalfe in 1976 Transfers data between computers Key element in nearly every computer network • Including Internet Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Computer is on network if: computer can access other computers or share hardware with other computers Networks in home Access surveillance and monitoring devices Control media devices Share hardware and software Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Sharing networked hardware Reduce costs Expand access Sharing networked software Reduce costs Facilitate data sharing Enable collaboration Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Disadvantages of network connection Vulnerability to unauthorized access Susceptibility to malicious code Most computer owners believe that advantages far outweigh disadvantages Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Network is like spider web with many interconnecting points Node - each connection point • Network nodes typically contain computers, networked peripherals, or network devices Server Computer connected to network that distributes resources to network users Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Networks Network connects computers and peripherals Computer Concepts – Illustrated Introductory, Seventh Edition Classifying Networks Networks - classified according to size and geographic structure PAN (personal area network) LAN (local area network) NAN (neighborhood area network) MAN (metropolitan area network) WAN (wide area network) Computer Concepts – Illustrated Introductory, Seventh Edition Classifying Networks Networks Technologies Computer Concepts – Illustrated Introductory, Seventh Edition Classifying Networks Client / server network Must have at least one server and one or more clients Network computers can serve as clients or servers Computer Concepts – Illustrated Introductory, Seventh Edition Classifying Networks Server Computer that provides services to other computers the network (clients) Application server Runs application software for network workstations File server Stores files and supplies them to workstations on request Computer Concepts – Illustrated Introductory, Seventh Edition Classifying Networks Print server Handles jobs sent to network printers Workstation Network client, usually personal computer Computer Concepts – Illustrated Introductory, Seventh Edition Classifying Networks Peer-to-peer structure Does not have a server Workstations serve as both clients and servers Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware Network device Any electronic device that broadcasts network data, boosts signals, or routes data to destination Modems, network interface cards, hubs, switches, routers, gateways, bridges, repeaters Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware Modem Converts digital signals into signals that can travel over network Network interface card (NIC) Network circuitry needed to connect to network Ethernet card (Ethernet adapter) NIC designed to support Ethernet protocols Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware If computer does not have Ethernet adapter,can purchased and installed Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware USB and PC Ethernet adapters plug into ports on outside of system unit Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware Network hub Links two or more nodes of wired network Network switch Sends data only to network devices specified as destination Network router Transmits data from one network to another Used to connect LANs and WANs Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware Network Router Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware Special hardware for wireless networks Transceiver • Used to send and receive wireless data MIMO (multiple-input multiple-output) technology Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Network Hardware Networked peripheral Any device with built-in network circuitry Can connect directly to network Network attached storage (NAS) Storage device that directly connects to network Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Communications channel (network link) - physical path or frequency for signal transmission Used for transporting data Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Wired network Data travels from one device to another over cables Wireless network Data travels through air, no need for cables Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Types of cables Twisted pair Shielded twisted pair (STP) Coaxial (coax) Fiber-optic Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Buying cable - choose Category 5 (Cat 5) or Category 6 (Cat 6) Rating indicates capacity Higher number, higher capacity Cables can be purchased in variety of lengths Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Ethernet network cables terminated at each end with RJ45 connector Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Bandwidth Transmission capacity of communications channel • High-bandwidth systems include cable and DSL (broadband) • Systems with less capacity include dial-up, referred (narrowband) Computer Concepts – Illustrated Introductory, Seventh Edition Exploring Data Transport Other cables can be used to transport data over wired network USB, serial, parallel, SCSI, and FireWire Wireless networks transport data via RF (radio frequency) signals Microwaves Infrared lights Computer Concepts – Illustrated Introductory, Seventh Edition Comparing Wireless and Wired Technology Wired networks Fast, secure, reliable, simple to configure Wireless Provide mobility No unsightly wires or cables to tangle No need to run wires through walls, ceilings, floors Computer Concepts – Illustrated Introductory, Seventh Edition Comparing Wireless and Wired Technology Wired network is best choice if you need speed Wired networks more secure than wireless networks Wireless signals pass through air and can be intercepted more easily Computer Concepts – Illustrated Introductory, Seventh Edition Comparing Wireless and Wired Technology Range limits Wired network - defined by longest cable in configuration Wireless network - depends on type of signal, transmitter strength, and physical environment Signal strength of wireless network Computer Concepts – Illustrated Introductory, Seventh Edition Comparing Wireless and Wired Technology Prices have equalized between wired and wireless networks May need some additional equipment for wireless • Wi-Fi card • Wireless access point or router Computer Concepts – Illustrated Introductory, Seventh Edition Installing a LAN Place router in central location, plug into surge protected outlet Run cables from router to Ethernet adapter in each workstation Run cable from Internet device and router’s WAN port Turn on devices, computer should recognize and establish connection Computer Concepts – Illustrated Introductory, Seventh Edition Installing a LAN Before using network, adjust router configuration settings Computer Concepts – Illustrated Introductory, Seventh Edition Installing a LAN Other ways to set up wired network HomePNA network uses telephone wiring in home Power-line network uses existing electrical wiring Computer Concepts – Illustrated Introductory, Seventh Edition Installing a LAN Power-line networks form infrastructure of LAN using existing electrical wiring Special NIC to connect computer to standard electrical outlet Computer Concepts – Illustrated Introductory, Seventh Edition Sharing Network Resources Wireless and wired devices can be connected to same network Most wireless routers include ports for Ethernet cables and WAN port for cable to Internet device Computer Concepts – Illustrated Introductory, Seventh Edition Sharing Network Resources Access network by clicking workgroup name May also have to enter password and user ID SSID (service set identifier) Helps log into correct network in places where networks may overlap Computer Concepts – Illustrated Introductory, Seventh Edition Sharing Network Resources To add workstations Turn on computer with wireless capabilities Choose correct network Enter network key or passphrase Workstation owners can specify whether files and locally attached printers can be accessed from other workstations on network Computer Concepts – Illustrated Introductory, Seventh Edition Sharing Network Resources File Sharing Computer Concepts – Illustrated Introductory, Seventh Edition Sharing Network Resources Three ways to connect printer to network using Windows Control Panel Connect it to one workstation in network Network print server Connect printer directly to hub or router Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology Internet backbone Consists of high-speed fiber-optic cables connecting high-capacity routers that direct network traffic Provide main high-speed routes for data traffic Network service providers (NSP) maintain backbone links and routers NSP equipment and links are tied together by network access points (NAPs) Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology Connecting computer to Internet Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology ISP equipment offers variety of services e-mail, chat groups, IM capabilities, music file sharing, FTP, and more Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology Upstream speed Rate of data transmitted from computer to Internet Downstream speed Rate of data arriving at computer Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology Internet uses variety of communications protocols Support basic data transport and services • TCP – Breaks message or file into packets • IP – Addresses packets so they can be routed to destinations Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology Main Protocols used on Internet Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology PING (Packet Internet Groper) Sends signal to specific Internet address Waits for reply Reports elapsed time between sending and receiving signal Traceroute Records packet’s path from your computer to destination Computer Concepts – Illustrated Introductory, Seventh Edition Introducing Internet Technology Connection options Fixed Internet access - links to ISP from stationary point Portable Internet access - allows easy movement of access device Mobile Internet access – allows Internet use on the go Computer Concepts – Illustrated Introductory, Seventh Edition Exploring IP Addresses and Domain Names IP address - Series of numbers 204.127.129.001 Each section called ‘octet’ Each address requires 32 bits Four sections create classes of IP addresses • Based on size, type of network, other functions ICANN (Internet Corporation for Assigned Names and Numbers) • Coordinates allocation of IP addresses, and more Computer Concepts – Illustrated Introductory, Seventh Edition Exploring IP Addresses and Domain Names IP addresses - assigned by ISPs or network or system managers IP addresses can also be obtained through DHCP (Dynamic Host Configuration Protocol) Computer Concepts – Illustrated Introductory, Seventh Edition Exploring IP Addresses and Domain Names Dynamic IP addresses Temporary address Generally assigned to computers running client software for accessing Web, email, listening to Internet radio, chat groups Static IP address Permanent address Assigned to ISPs, Web sites, Web hosting services, email servers Computer Concepts – Illustrated Introductory, Seventh Edition Exploring IP Addresses and Domain Names Domain name Corresponds to unique IP address entered into database called Domain Name System Domain name server – any computer that hosts this database Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires Dial-up connection POTS (plain old telephone service) is used to transfer data Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires Voiceband modem Converts digital signals from computer into analog signals for telephone lines Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires ISDN (Integrated Services Digital Network) Fixed Internet connection moves data over ordinary telephone lines Use telephone wall jack as fixed point of connection Connect computer to ISDN terminal adapter which sends digital signals Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires DSL (digital subscriber line) High-speed, digital, always-on Internet access Uses standard phone lines to transport data Requires modem and filters Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires Dedicated line T1, T3, and T4 services - high-capacity dedicated lines can be leased from telephone company Not used by other customers Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires Cable connection Provides always-on broadband Internet access over same infrastructure that offers cable television services Bandwidth is divided to offer both television and Internet access Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet with Wires Connecting to Internet via cable TV Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet without Wires Satellite Internet service Means of distributing always-on, highspeed, asymmetric Internet access Broadcasting signals to and from personal satellite dish Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet without Wires Fixed wireless Internet service (wireless broadband) Internet access to homes and businesses by broadcasting data signals over areas large enough to cover most cities and outlying areas WiMAX (Worldwide Interoperability for Microwave Access) – well-known fixed wireless standard Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet without Wires Public Wi-Fi network Wireless LAN that provides open access to public In many public places such as bookstores, coffee shops, airports, hotels, and restaurants Wi-Fi hotspot Range of Wi-Fi network’s coverage Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet without Wires Mobile WiMAX Designed to offer Internet access with seamless handoff from coverage area of one tower to another Portable satellite Internet service - available for those who need access when traveling in remote locations Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet without Wires WAP (Wireless Access Protocol) Communications protocol providing wireless Internet access from handheld devices Computer Concepts – Illustrated Introductory, Seventh Edition Connecting to the Internet without Wires Mobile broadband Allows access to full spectrum of Internet via handheld device Requires fast connection, data service subscription, and mobile broadband equipment Computer Concepts – Illustrated Introductory, Seventh Edition Talking Points: Why pay for Internet access if you can get it for free? Free wireless LANs (WLAN) Found in airports, hotels, coffee shops Sometimes offered by rogue WLAN operators who buy service, then distribute connections over wireless LANs to friends, neighbors, and anyone who passes by But is this free access always legal? Computer Concepts – Illustrated Introductory, Seventh Edition Talking Points: Why pay for Internet access if you can get it for free? Problems include Piggyback use Data security Providers feel every person using free Wi-Fi is one fewer customer Wisdom of unregulated network availability is questioned by resulting ethical, security, and privacy issues Computer Concepts – Illustrated Introductory, Seventh Edition