ESSENTIALS CHAPTER computing Connectivity the Wireless Revolution and

ESSENTIALS CHAPTER computing Connectivity, the Wireless Revolution, and Communications Copyright 2003 The Mc. Graw-Hill Companies, Inc. 7 1

computing ESSENTIALS Competencies Connectivity Wireless Revolution Communication systems Connection devices Transmissions and protocols Network architecture Copyright 2003 The Mc. Graw-Hill Companies, Inc. 2

computing ESSENTIALS Connectivity l Computer networks that link people and resources l Other computers l Large storage devices l Internet Copyright 2003 The Mc. Graw-Hill Companies, Inc. 3

computing ESSENTIALS Wireless Revolution l l l Wireless and mobile telephones l Most dramatic change in connectivity l Connected all the time anywhere Originally voice communication Computer communications l Bluetooth l Device connections Copyright 2003 The Mc. Graw-Hill Companies, Inc. 4

computing ESSENTIALS Communication Systems l Electronic systems that transmit and receive information l Basic elements l Sending/Receiving device l Communication channel l Connection devices l Data transmission specifications Copyright 2003 The Mc. Graw-Hill Companies, Inc. 5

computing ESSENTIALS Communication Channels l Essential element of communication system l Two categories l Physical connection l Wireless connection Copyright 2003 The Mc. Graw-Hill Companies, Inc. 6

computing ESSENTIALS Wired Connections l Telephone lines l Twisted pair l Old standard • Coaxial cable – Single solid-copper core – 80 times faster • Fiber-optic cable – Light through glass – 26, 000 times faster Copyright 2003 The Mc. Graw-Hill Companies, Inc. 7

computing ESSENTIALS Wireless Connections l l Microwave l High-frequency radio waves l Line-of-sight communication l Relayed Satellite l Microwave relay stations l Geostationary l Large volume of data Copyright 2003 The Mc. Graw-Hill Companies, Inc. 8

computing ESSENTIALS Connection Devices l l l Modulator-demodulator l Converts analog signal to digital signal Speed in bits per second (bps) External Internal PC Card Wireless Copyright 2003 The Mc. Graw-Hill Companies, Inc. 9

computing ESSENTIALS Connection Types l l l Dial-up service l Most popular, but slow T 1 – T 4 lines l Special high-speed lines Digital subscriber line (DSL) l Uses existing phone lines, fast Cable l Existing television cables Satellite/air connection services l Slower than DSL, but faster than dial-up Copyright 2003 The Mc. Graw-Hill Companies, Inc. 10

computing ESSENTIALS Data Transmission l Bandwidth l How much information can be transmitted at one time l Protocol l Specific rules guiding the exchange of information Copyright 2003 The Mc. Graw-Hill Companies, Inc. 11

computing ESSENTIALS Bandwidth l l Measurement of capacity of the communication channel Categories l Voiceband l Standard phone line, dial-up l Medium band l Special leased lines l Broadband l High capacity transmissions l DSL, cable, satellite Copyright 2003 The Mc. Graw-Hill Companies, Inc. 12

computing ESSENTIALS Data Transmission Direction l Simplex l l Half-duplex l l One direction only One direction at a time Full-duplex l Both direction simultaneously Copyright 2003 The Mc. Graw-Hill Companies, Inc. 13

computing ESSENTIALS Protocols l l Set of communication rules for exchange of information Transmission control protocol/Internet protocol (TCP/IP) l Identification l IP Address l Domain name system (DNS) l Reformatting l Reassemble packets Copyright 2003 The Mc. Graw-Hill Companies, Inc. 14

computing ESSENTIALS Networks l l Two or more connected computers that share information and resources Node l Device connected to a network Client l Node that requests and uses resources available from other nodes Server l Node that shares resources with other nodes Copyright 2003 The Mc. Graw-Hill Companies, Inc. 15

computing ESSENTIALS More Network Terms l l l Network operating system (NOS) l Software to control and coordinate activities between nodes on a network Distributed processing l Computing power located and shared at different locations Host computer l Large centralized computer, usually a mainframe Copyright 2003 The Mc. Graw-Hill Companies, Inc. 16

computing ESSENTIALS Network Architecture l l l Arrangement of network communication channel Coordinates and shares resources Topology l Star network l Bus network l Ring network l Hierarchical Copyright 2003 The Mc. Graw-Hill Companies, Inc. 17

computing ESSENTIALS Star Network Copyright 2003 The Mc. Graw-Hill Companies, Inc. 18

computing ESSENTIALS Bus Network Copyright 2003 The Mc. Graw-Hill Companies, Inc. 19

computing ESSENTIALS Ring Network Copyright 2003 The Mc. Graw-Hill Companies, Inc. 20

computing ESSENTIALS Hierarchical Network Copyright 2003 The Mc. Graw-Hill Companies, Inc. 21

computing ESSENTIALS Strategies l Ways to coordinate sharing of resources l Most common l Terminal network system l Peer-to-peer network system l Client/Server network system l Enterprise computing Copyright 2003 The Mc. Graw-Hill Companies, Inc. 22

computing ESSENTIALS Network Types l Networks differ in geographical size l Types of networks l Local Area Network (LAN) l Metropolitan Area Network (MAN) l Wide Area Network (WAN) Copyright 2003 The Mc. Graw-Hill Companies, Inc. 23

computing ESSENTIALS Local Area Networks l Computers and devices linked in close proximity to each other l Typically use a bus form of organization l Network gateways l Network bridge Copyright 2003 The Mc. Graw-Hill Companies, Inc. 24

computing ESSENTIALS Metropolitan Area Networks l Link nodes and resources within the geographical bounds of a city l Link between buildings l Cellular phones can extend the reach of a MAN Copyright 2003 The Mc. Graw-Hill Companies, Inc. 25

computing ESSENTIALS Wide Area Networks l Countrywide and worldwide network l Use microwave relays and satellites l Internet l Widest of all WAN Copyright 2003 The Mc. Graw-Hill Companies, Inc. 26

computing ESSENTIALS Look to Future l l Wireless robotic car Toyota and Sony collaboration l Pod l Connects wirelessly to portable terminal l Download l l songs from Internet Use GPS to determine location Communicate with other cars Copyright 2003 The Mc. Graw-Hill Companies, Inc. 27