Communication Links Communication Link = Physical connection or Physical Medium Types: Wire Pair or Twisted Pair Coaxial Cable Fiber Optics Bandwidth,
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Presentation on theme: "Communication Links Communication Link = Physical connection or Physical Medium Types: Wire Pair or Twisted Pair Coaxial Cable Fiber Optics Bandwidth,"— Presentation transcript:
1 Communication LinksCommunication Link = Physical connection or Physical MediumTypes:Wire Pair or Twisted PairCoaxial CableFiber OpticsBandwidth, Optical Fiber, Light as medium, Low noise susceptibility as compared to othersMicro Wave TransmissionSatellite TransmissionTransponder, Geosynchronous sat. 22,300 miles
3 Microwave and satellite transmission Microwave and satellite transmission. (a) To relay microwave signals, dish-shaped antennas such as these are often located atop buildings, towers, and mountains. Microwave signals can follow a line-of-sight path only, so stations must relay this signal at regular intervals to avoid interference from the curvature of the earth. (b) In satellite transmission, a satellite acts as a relay station and can transmit data signals from one earth station to another. A signal is sent from an earth station to the relay satellite, which changes the signal frequency before transmitting it to the next earth station. Transponder
5 ProtocolsSet of rules for the exchange of data between a terminal and a computer or between two computeror precommunication agreement about the form in which messages or data is to be sent and receipt acknowledged.two devices must be able to ask each other questions (Are you ready to receive a message? Did you get my last message? Is there trouble at your end?) and to keep each other informed
6 Standard Protocolsoftware development can be a nightmare because different vendors use different protocols. Standards helpCommunications standards exist and are constantly evolving and being updated for new communications formsthe most important protocol is the one that makes Internet universality possible called Transmission Control Protocol/ Internet Protocol (TCP/IP)
7 Network Topologies Physical Layout Node (any computer or component) TypesStarHub computerMessage routed through hub computerRingUnidirectional, one at a timeBusPossible collision, retry if collision
8 Kinds of Network WAN (wide area network) MAN (Metropolitan area network)Mainframe to PC connectionTerminal emulation softwareMicro to mainframeHost computerFile transfer softwareDownload, Upload
9 Kinds of Network LAN (local area network) Physical Medium Twisted Pair, Co-Axial Cable, Fiber optics etc.Wireless (using infra-red or radio waves) – Easy to install and configure but slow and of short range.NIC (network interface card)The card contains circuitry that handles sending, receiving, and error checking of transmitted data.
10 Networking Components BridgeSimilar networks can be connected by a bridge, a hardware/software combination that recognizes the messages on a network and passes on those addressed to nodes in other networksRouterA router is a special computer that directs communications traffic when several networks are connected together. If traffic is clogged on one path, the router can determine an alternative pathIP SwitchIP used as Protocolrouters are being replaced with IP switches, which are less expensive and, since no translation is needed, faster than routers
11 Networking Components GatewayA gateway is a collection of hardware and software resources that lets a node communicate with a computer on another dissimilar networkThe main task of Gateway is Protocol conversion
12 Types of LAN Client Server Peer to Peer Thin client: A computer that has no disk storage ability and is used basically to send input to the server for processing and then receive the outputPeer to PeerAll computers in a arrangement have equal status
13 LAN Protocols Ethernet Token Ring the network protocol that dominates the industryuses a high-speed network cable.Ethernet uses a bus topology and is inexpensive and relatively simple to set up.The transmission method used by Ethernet is know as: “carrier sense multiple access with collision detection” or CSMA/CDToken RingToken neededToken Ring Uses Ring topology
14 Work of Networking Office Automation E-mail Fax (Facsimile) Groupware TeleconferencingVideo conferencingEDI (electronic Data Interchange)Electronic Fund Transfer: Instant BankingATM machinesTelecommutingOnline servicesWeather, news, online ordering of food, clothing etc.