Introduction to Networking & TelecommunicationsStarsLearning ObjectivesComputer NetworkSlide 5Why Networking ?The Language of Computer NetworksVoice & Data CommunicationsCircuit Switching and Reserved CapacityPros and cons of Reserved CapacityPacket-Switching Data NetworksSlide 12The Big Picture of NetworksSlide 14Elements of a Simple LANSlide 16Slide 17Slide 18Hub operationSwitch operationSummary QuestionsSummary Questions (cont.)Slide 23Introduction to Networking & Telecommunications School of BusinessEastern Illinois University © Abdou Illia, Spring 2007(Week 1, Tuesday 1/9/2007)2StarsSomething to which you should pay special attention.Multiple stars are for especially important or difficult material3Learning ObjectivesYou should be able to describe basic Networking Concepts in wide use today:Basic terminology of computer networksVoice and Video Communications Versus Data CommunicationsCircuit Switching Versus Packet SwitchingComponents of a simple computer network4Computer NetworkAn interconnection of computers and computing equipment using either wires or radio waves over small or large geographic distances“Connect to GHI”ABCDEFGHIJKLMNO5Computer NetworkLocal area network - networks that are small in geographic size spanning a room, building, or campusMetropolitan area network - networks that serve an area of 3 to 30 miles - approximately the area of a typical cityWide area network - a large network that encompasses parts of states, multiple states, countries, and the world6Why Networking ? Resource sharing High reliability–Same resources at different places–Fault tolerance Cost saving Communication tool7The Language of Computer NetworksVoice network - a network that transmits telephone signalsVoice communication - Transmission of analog data (specifically spoken words) usually between peopleTelecommunications - the study of telephones and the systems that transmit telephone signalsData network - a network that transmits computer dataData communications - the transfer of digital or analog data using digital or analog signalsNetwork management - the design, installation, and support of a network and its hardware and software8Voice & Data CommunicationsOriginally, There was a Sharp Distinction:–Voice Communication–Data Communications, in which one or both parties is a computer Database Electronic mail World Wide WebDistinction is fading because voice communication is increasingly computer-based9Circuit Switching and Reserved Capacity –Circuit capacity is reserved during duration of each call–At each switch–On each trunk lineCircuitReservedCapacityReservedCapacity10Pros and cons of Reserved CapacityNothing like the congestion on the InternetReserved Circuit Capacity is Expensive–Have to Pay for it whether you use it or not–Good for voice, because conversations are fairly constant–Bad for data, because most data transmission is bursty; e.g., in World Wide Web, download, then stare at screen for a long time until next download11Packet-Switching Data NetworksPacket Switching–Large messages are broken into small pieces called packets (or frames)–Packets are short (averaging a few hundred bytes) because networking devices handle short messages more efficientlyMessagePackets12Packet-Switching Data NetworksMultiplexing–Packets from many conversations are mixed (multiplexed) over each trunk lineMultiplexing onTransmission LinePacket Switching13The Big Picture of Networks.14The Big Picture of NetworksWorkstationsPCs or terminals used to receive services form the NetworkServersComputers that store the Network software and shared or private user files. It provides service to workstations.hubs (or switches)Collection points for wires that interconnect WorkstationsBridgesConnecting devices between separate LANsRoutersConnecting devices between LANs and WANsNodesComputing devices that make decisions as to which route a piece of data will follow next15Elements of a Simple LANHub or SwitchMedia16Elements of a Simple LANHub or SwitchMediaHub or Switch: Devicethat connect all stationsMedia: Wired or Wireless transmission media used to transfer data.17Elements of a Simple LANClient PCClient PCClient PCs are used byordinary managers andProfessionals. Receive servicesServers provide servicesto client PCs18Elements of a Simple LANF i g u r e 1 . 5 : S m a ll P C N e t w o r k B u il t o n a L A NH u b o r S w it c hB u s i n e s s T e l e p h o n e W i r eN e t w o r kI n t e r f a c eC a r dN I CC l i e n tP CS e r v e rNIC: Device that provides a dedicated connection to the network. Includes a physical address called MAC address191.Station A transmitsto the Hub2.Hub broadcaststo all stationsStation C must wait,or its signal willcollide with Station A'ssignalStationAStationBStationCStationAStationBStationCHub operationHubs split available bandwidth among computers, i.e. with a 100 Mbps hub, the network speed will be 100 Mbps / n (where n is the number of computers)Active hubs include repeater capabilities for regenerating signals.Passive hubs don't regenerate signals. Limited to a 30meter distance apart from computers.(Except sending station)20Switch operationStationCStationDSwitchStationBStation ATransmitsto Station CSwitch SendsSignal out aSingle Port162345StationAStation BTransmitsSimultaneouslyto Station DSwitches send out a single port: destination port.Most switches can efficiently handle simultaneous transmissionsSwitches provide a full bandwidth to all connected computers.21Summary Questionsa) Define the following:–Computer Network  Data communications–Voice Network  Network managementb) Distinguish between voice and data communications.c) Distinguish between circuit switching and packet switching. d) List and explain the elements of a Simple Network4,789-1215-22Summary Questions (cont.)What category of network is illustrated here?23Summary Questions (cont.)What category of network is illustrated