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computing ESSENTIALS 9 Connectivity, the Wireless Revolution, and Communications 1 computing ESSENTIALS Competencies Connectivity Wireless Revolution Communication systems Connection devices Transmissions and protocols Network architecture 2 computing ESSENTIALS Connectivity Computer networks that link people and resources Other computers Large storage devices Internet 3 computing ESSENTIALS Wireless Revolution Wireless and mobile telephones Most dramatic change in connectivity Connected all the time anywhere Originally voice communication Computer communications Bluetooth Device connections 4 computing ESSENTIALS Communication Systems Electronic systems that transmit and receive information Basic elements Sending/Receiving device Communication channel Connection devices Data transmission specifications 5 computing ESSENTIALS Communication Channels Essential element of communication system Two categories Physical connection Wireless connection 6 computing ESSENTIALS Wired Connections Telephone lines Twisted pair Old standard • Coaxial cable – Single solid-copper core – 80 times faster • Fiber-optic cable – Light through glass – 26,000 times faster 7 computing ESSENTIALS Wireless Connections Microwave High-frequency radio waves Line-of-sight communication Relayed Satellite Microwave relay stations Geostationary Large volume of data 8 computing ESSENTIALS Connection Devices Modulator-demodulator Converts analog signal to digital signal Speed in bits per second (bps) External Internal PC Card Wireless 9 computing ESSENTIALS Connection Types Dial-up service Most popular, but slow T1 – T4 lines Special high-speed lines Digital subscriber line (DSL) Uses existing phone lines, fast Cable Existing television cables Satellite/air connection services Slower than DSL, but faster than dial-up 10 computing ESSENTIALS Data Transmission Bandwidth How much information can be transmitted at one time Protocol Specific rules guiding the exchange of information 11 computing ESSENTIALS Bandwidth Measurement of capacity of the communication channel Categories Voiceband Standard phone line, dial-up Medium band Special leased lines Broadband High capacity transmissions DSL, cable, satellite 12 computing ESSENTIALS Data Transmission Direction Simplex Half-duplex One direction only One direction at a time Full-duplex Both direction simultaneously 13 computing ESSENTIALS Protocols Set of communication rules for exchange of information Transmission control protocol/Internet protocol (TCP/IP) Identification IP Address Domain name system (DNS) Reformatting Reassemble packets 14 computing ESSENTIALS Networks Two or more connected computers that share information and resources Node Device connected to a network Client Node that requests and uses resources available from other nodes Server Node that shares resources with other nodes 15 computing ESSENTIALS More Network Terms Network operating system (NOS) Software to control and coordinate activities between nodes on a network Distributed processing Computing power located and shared at different locations Host computer Large centralized computer, usually a mainframe 16 computing ESSENTIALS Network Architecture Arrangement of network communication channel Coordinates and shares resources Topology Star network Bus network Ring network Hierarchical 17 computing ESSENTIALS Star Network 18 computing ESSENTIALS Bus Network 19 computing ESSENTIALS Ring Network 20 computing ESSENTIALS Hierarchical Network 21 computing ESSENTIALS Strategies Ways to coordinate sharing of resources Most common Terminal network system Peer-to-peer network system Client/Server network system Enterprise computing 22 computing ESSENTIALS Network Types Networks differ in geographical size Types of networks Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) 23 computing ESSENTIALS Local Area Networks Computers and devices linked in close proximity to each other Typically use a bus form of organization Network gateways Network bridge 24 computing ESSENTIALS Metropolitan Area Networks Link nodes and resources within the geographical bounds of a city Link between buildings Cellular phones can extend the reach of a MAN 25 computing ESSENTIALS Wide Area Networks Countrywide and worldwide network Use microwave relays and satellites Internet Widest of all WAN 26 computing ESSENTIALS Look to Future Wireless robotic car Toyota and Sony collaboration Pod Connects wirelessly to portable terminal Download songs from Internet Use GPS to determine location Communicate with other cars 27