significance of networking in communication technologies | My Assignment Tutor

25/09/20171• Introduction to the unit contents, assessment types,the significance of networking in communicationtechnologies.• Investigate the purpose, resource implications,communications, working practice, commercialopportunity, information sharing and collaboration• Discuss the benefits and constraints of differentnetwork types and standards• Overview of OSI networking standards and explorethe functionalities of different layers.• Explore and analyse conceptual models (e.g. OSImodel, TCP/IP model), standards (e.g. IEEE 802.x)• Gain knowledge on 7-layer OSI reference modelObjectivesOBJECTIVESLO1 Examine networking principles and their protocols Learning Contract Lectures Do not cover everything Higher grades requiresmore attention anddetails Students responsibility Attend lectures Read textbook Assignment writing Ask questionsWhy ? Motivation Encouragement Fairness Efficiency Collaboration & Care Listen when someone else is speaking Raise your hand when you need help / ask question Be Specific, Measurable, Achievable and Timed Treat other with respect and use positive languageNetworking 225/09/20172Burgess, M., 2003. Principles of Networkand System Administration. 2nd ed.Chichester: John Wiley and Sons Ltd.Hallberg, B., 2005. Networking: ABeginner’s Guide. 4th ed. Osborne:Mcgraw-Hill.Limoncelli, T. & Hogan, C., 2001. ThePractice Of System and NetworkAdministration. London: Addison-Wesley.Lowe, D., 2005. Networking All-In-OneDesk Reference For Dummies. 2nd ed.New York: Hungry Minds Inc.Olifer, N. & Olifer, V., 2005. ComputerNetworks: Principles, Technologies AndProtocols For Network Design.Chichester: John Wiley And Sons Ltd.Stallings, W., 2003. Data and ComputerCommunications. 7th ed. New York:Prentice Hall.Networking 3Subramanian, M., (2000). NetworkManagement: An Introduction toPrinciples and Practice. Chichester:Addison-Wesley.Tanenbaum, A., 2002. ComputerNetworks. London: Prentice Hall Ptr.Dean, T., (2009). CompTIA Network+ 2009In Depth. Boston : Course Technology.Dye, M. A., McDonald, R. & Rufi, A. W.,(2008). Network Fundamentals: CCNAExploration Companion Guide.Indianapolis : Cisco Press .Lewis, W., (2009). CCNA ExplorationCourse Booklet : LAN Switching andWireless.Indianapolis : Cisco PressNetworking 425/09/20173 Learning Outcomes and Assessment CriteriaPassMeritDistinctionLO1 Examine networking principles and their protocolsLO1 & 2D1 Considering a givenscenario, identify thetopology protocol selectedfor the efficient utilisation ofa networking system.P1 Discuss the benefits andconstraints of different networktypes and standards.P2 Explain the impact of networktopology, communication andbandwidth requirements.M1 Compare common networkingprinciples and how protocolsenable the effectiveness ofnetworked systems.LO2 Explain networking devices and operationsP3 Discuss the operatingprinciples of networking devicesand server types.P4 Discuss the inter-dependenceof workstation hardware withrelevant networking software.M2 Explore a range of servertypes and justify the selection of aserver, considering a givenscenario regarding cost andperformance optimisation. Learning outcomes, passes, merits and distinctions. Introduction to assignment brief.Networking 5 Learning Outcomes and Assessment CriteriaPassMeritDistinctionLO3 Design efficient networked systemsP5 Design a networked system tomeet a given specification.P6 Test and evaluate the design tomeet the requirements and analyseuser feedback.M3 Install and configurenetwork services andapplications on your choice.D2 Design a maintenanceschedule to support thenetworked system.LO4 Implement and diagnose networked systemsP7 Implement a networked systembased on a prepared design.P8 Document and analyse testresults against expected results.M4 Recommend potentialenhancements for thenetworked systems.D3 Use critical reflection toevaluate own work and justifyvalid conclusions. Networking 625/09/20174 What is a Network Human network… to exchange knowledge (news), etc.. In the Café, in the club, professionals of different subjects etc.. What is a Computer Network“A computer network is an interconnected collection ofautonomous computers” Interconnection : enables the exchange of data and information, usingvarious media.o Data : simple and seemingly random and useless until it is organised.o Information : processed data, structured and organised in a given context.o Media:• Copper (telephone, LANs)• Microwaves (telephone, satellite)• fibre optics (light, telephone, data) Autonomous(a) possessed of autonomyo Autonomy(n). right of self government; personal freedom; freedom ofwillSee: conciseoxforddictionarySee: conciseoxforddictionaryNetworking 825/09/20175 Resource SharingPhysicalExpensive resources such as Multifunction printer, Plotters,Scanners can be shared between many users at the same time(Reduce operating costs)Software & dataData storage units, application software can be stored at acommon location by which all users can access them (Reduceoperating costs)Networking 9Elimination of geographic constraintsWorking from homeflexible working patterns Cheaper Officeso hot desking (Reduce operating costs) less direct contact with co-workers.+/-Centralised administration (Reduce operating costs)IT staff and co-workers can manage and administer the networkfrom one single point of presenceIT administrators can remotely Add, change and administerusers permissionIt administrators can support users remotely across the networkNetworking 1025/09/20176Information Internet, home-banking, stock trading.Communication email, video-conferencing, news groups.Entertainment video on demand, multi-user doom, swapping of gamesSocial Implications Network neutralityContent ownershipPrivacyTheft(no network restrictions +-)e.g., (JPG, Camera)e.g., Web tracking and profilinge.g., botnets and phishing Networking 11A Converged Network is one where voice and videocommunications have been combined on a single datanetwork.Legacy Equipment:Until now, mainly feasible on large enterprise networks.Networking 1225/09/20177Advanced Technology:More popular to medium and small sized businesses.Can be a difficult decision considering current investments intechnology.Benefit:Only one network to manage.Networking 13New Options:You can now tie voice and video communications directlyinto an employee’s personal computer system. Software integrated on a PC eliminates an expensivehandset. Add a webcam and video conference.Networking 1425/09/20178Scale Type VicinityPAN (Personal Area Network)BuildingLAN (Local Area Network)CityMAN (Metropolitan Area Network)CountryWAN (Wide Area Network)PlanetThe Internet (network of all networks) • Networks can be classified by their scale:Networking 1525/09/20179 Let us experiment Let us Reflect Look at the final product, (was it identical?) Three lines in total How many words needed to accomplish the task? What are the difficulties arises? Were there any noise created during the task? Will it be better if we are to face each other? Were there any terminology used? will it help? Clarification(interference)( topology )Networking 17Local area networks are defined in terms of the protocol andthe topology used for accessing the networkProtocolis the set of rules established for the users to gain control of the networkto exchange information, (the method by which hosts communicate andexchange data/information)Topologyis the network architecture used to interconnect the networkingequipment, (the physical layout by which hosts aliened and connected toeach others)Networking 1825/09/201710Reflect:Isosceles triangleEquilateral triangleSquare with round anglesEasy to DrawEstablished a committee in 1977 todevelop an architecture for computercommunication OSI : Open Systems Interconnection OSI reference model is the result ofthis effort In 1984, OSI reference model wasapproved as an international standardfor communications architecture “open” ”It denotes that the standard’sspecifications are publicly available”All – People – Seem – To – Need – Data – ProcessingPlease – Do – Not – Throw – Salami – Pizza – AwayISO : International Standards OrganisationNetworking 2025/09/201711Why? Layer architecture simplifies the network design It is easy to debug network applications in a layeredarchitecture network The network management is easier due to the layeredarchitecture Network layers follow a set of rules, called protocol The protocol defines the format of the data beingexchanged, and the control and timing for the handshakebetween layers The process of breaking up the functions or tasks ofnetworking into layers reduces complexity Think(Production Line)Each layer provides a service to the layer above it inthe protocol specification The lower “4 layers” (transport, network, data link andphysical — Layers 4, 3, 2, and 1) are concerned with the flow ofdata from end to end through the network The upper “3 layers of the OSI model” (application,presentation and session — Layers 7, 6 and 5) are orientatedmore toward services to the applicationsNetworking 21 A principled, international standard, seven layer model to connectdifferent systems LayerFunctionProtocolApplicationProvides functions neededby usersFTP, DNS, HTTP, DHCP etc..PresentationConverts differentrepresentationsASCII, GIF, MPEG etc..SessionManages task dialogsControl Sessions betweenApplicationsTransportProvides end-to-enddeliveryTCP, UDP, SPX etc..NetworkSends packets over multiplelinksIPv4, IPv6, IPX, IPSECDataSends frames of information802.3 (Ethernet), ATM,Frame-RelayPhysicalSends bits as signalsHubs, RepeatersBits (0101001) as electricalsignal Networking 2225/09/201712DataSegmentPacketFrameBitsNetworking 23Each layer solves a particular problem but must include mechanisms toaddress a set of recurring design issues IssueExample mechanisms at different layersReliability despitefailuresCodes for error detection/correction Routingaround failuresNetwork growthand evolutionAddressing and naming Protocol layeringAllocation ofresources likebandwidthMultiple access Congestion controlSecurity againstvarious threatsConfidentiality of messages Authentication ofcommunicating parties Networking 2425/09/201713 A four layer model derived from experimentation; omits some OSIlayers and uses the IP as the network layer.The TCP/IP model with some protocols we will study.Networking 25OSI+ Very influential model with clearconcepts─ Models, protocols and adoption allbogged down by politics andcomplexityTCP/IP+ Very successful protocols thatworked well and thrived– Weak model derived after the factfrom protocolsNetworking 2625/09/201714Networking 27Networking 2825/09/201715 Physical Layer Provides physical interface for transmission of information Defines rules by which bits are passed from one system to another on aphysical communication medium Covers all – mechanical, electrical, functional and procedural – aspectsfor physical communication Such characteristics as voltage levels, timing of voltage changes,physical data rates, maximum transmission distances, physicalconnectors, and other similar attributes are defined by physical layerspecificationsNetworking 29ModulationCarrier waveSinusoidal modulating signalAmplitude-modulated signalFrequency-modulated signalNetworking 3025/09/201716 StandardorganisationNetworking StandardsISO• ISO 8877 : Officially adopted the RJ connectors (e.g., RJ-11, RJ-45)• ISO 11801: Network cabling standard similar to EIA/TIA 568.EIA/TIA• TIA-568-C: Telecommunications cabling standards, used by nearly all voice,video and data networks.• TIA-569-B: Commercial Building Standards for TelecommunicationsPathways and Spaces• TIA-598-C: Fibre optic colour coding• TIA-942 : Telecommunications Infrastructure Standard for Data CentresANSI• 568-C: RJ-45 pinouts. Co-developed with EIA/TIAITU-T• G.992: ADSLIEEE• 802.3: Ethernet• 802.11: Wireless LAN (WLAN) & Mesh (Wi-Fi certification)• 802.15: Bluetooth Networking 31 MediaPhysicalComponentsFrame EncodingTechniqueSignallingMethodCoppercable• UTP• Coaxial• Connectors• NICs• Ports• Interfaces• Manchester Encoding• Non-Return to Zero (NRZ) techniques• 4B/5B codes are used with Multi-LevelTransition Level 3 (MLT-3) signalling• 8B/10B• PAM5• Changes in theelectromagnetic field• Intensity of theelectromagnetic field• Phase of theelectromagnetic waveFibreOpticcable• Single-mode Fibre• Multimode Fibre• Connectors• NICs• Interfaces• Lasers and LEDs• Photoreceptors• Pulses of light• Wavelength multiplexing usingdifferent colours• A pulse equals 1.• No pulse is 0.Wirelessmedia• Access Points• NICs• Radio• Antennae• DSSS (direct-sequence spreadspectrum)• OFDM (orthogonal frequency divisionmultiplexing)• Radio waves Networking 3225/09/201717Networking 33Encoding Technique Nonreturn to Zero-Level (NRZ-L)Two different voltages for 0 and 1 bitsVoltage constant during bit intervalno transition i.e. no return to zero voltage, such as absenceof voltage for zeroconstant positive voltage for one more oftennegative voltage for one value and positive for the otherNetworking 3425/09/201718Encoding Technique Manchester Encodinghas transition in middle of each bit periodtransition serves as clock and datalow to high represents onehigh to low represents zeroused by IEEE 802.3common specified for the IEEE 802.3 (Ethernet)Networking 35Signalling MethodNetworking 3625/09/201719Physical ComponentsTwo main media categories:Guided ― wires, cablesTwisted-Pair cables:o Unshielded Twisted-Pair (UTP) cableso Shielded Twisted-Pair (STP) cablesCoaxial cablesFibre-optic cablesUnguided (wireless transmission)RadioMicrowaveInfraredNetworking 37Twisted-Pair CablesTwisted PairIf the pair of wires are not twisted, electromagnetic noises from,e.g., motors, will affect the closer wire more than the furtherone, thereby causing errorsNetworking 3825/09/201720 1. CAT 6 cables can use the full 100 metre length when used with 10/100/1000 BaseTnetworks, with 10GbaseT networks, CAT 6 is limited to 55 metres 2. CAT6a cables can use the full 100 metre length with networks up to 10GBaseT.Local Area Networking Technologies 39CATRating Max Frequency Max Bandwidth Status with TIA/EIA CAT1< 1MHzNo longer recognisedAnalogue phone linesonly4 MbpsCAT24 MHzNo longer recognisedCAT316 MHz16 MbpsNo longer recognisedCAT420 MHz20 MbpsNo longer recognisedCAT 5CAT 5eCAT 61CAT 6a2CAT 7cat 7a100 MHz100 MHz250 MHz500 MHz600 MHz1000 MHz100 Mbps1 Gbps10 Gbps10 Gbps10 Gbps10 GbpsNo longer recognisedRecognisedRecognisedRecognisedRecognisedRecognised Shielded Twisted-Pair (STP)The Shield Typically wrapped inside a plastic cover (for mechanical protection) A sample UTP cable with 4 shielded twisted pairs of wires STP cables are similar to UTP cables, except there is a metal foil orbraided-metal-mesh cover that encases each pair of insulated wiresNetworking 4025/09/201721Networking 41Coaxial CablesCoaxial CablesIn general, coaxial cables, or coax, carry signals of higherfrequency (100KHz–500MHz) than UTP cablesOuter metallic wrapping serves both as a shield against noiseand as the second conductor that completes the circuitNetworking 4225/09/201722Fibre-Optic CablesFibre-Optic CablesLight travels at 3×108 ms-1 in free spaceLight slows down in denser media, e.g. glassRefraction occurs at interface, with lightbending away fromthe normal when itenters a less densemediumNetworking 43Copper CablingPower over Ethernet (PoE)Wireless Access Points, Power IP phones, CCTV cameras, using thepower over Ethernet which drives the power through thenetworking cable itselfLess expensive componentsMore Flexible: TDM environments are built to run on copperinfrastructuresPulling Tension: According to TIA/EIA-568A standard isspecified in “ Cabling Practices“ The maximum pullingtension for 4-pair, UTP cables should not exceed 25 pound force(lbf), where basic fibre has a 100-200 pound tension limitNetworking 4425/09/201723Fibre CablingElectromagnetic : Optical Fibre is immune to electromagneticinterferenceHigh Bandwidth: Fibre has a higher bandwidth than copper Category 6A Cable handle a bandwidth up to 600 MHz over 100 meters Fibre Two kilometres between the hub and the nodeCost : fibre cable is less expensive than copper, but expensivecomponents are requiredLightweight, optical cable weighs less than a comparablecopper wire cableSecurity: Eavesdropping on copper cables only requires asensitive antenna to pick up the energy radiated from the cable fibre optic cable is difficult and can’t be done without causing attenuation an optical-time domain reflectometer will easily locate the location of a tapon fibre cablingNetworking 45Fibre CablingNon-flammable: Fibre is a dielectric, which means that thereisn’t any electrical current that flows through it,Distance & Attenuation: Attenuation measured in decibels (dB),the loss in fibre optic is much less than copper wire The maximum allowed industry standard of attenuation for multi-modefibre over a 100-meter distance is 0.15 dB.o The fibre looses only 3% of its original signal strength over 100meters. The maximum allowed industry standard of attenuation for Category 6Acable over 100 meters at 100 MHz is 20.9 dBo Category 6A cable Looses about 94% in signal strength The attenuation of fibre doesn’t change as bandwidth increases ordecreases.Networking 4625/09/201724 Implementation issuesCopper mediaFibre-opticBandwidth supported10 Mbps – 10 Gbps10 Mbps – 100 GbpsDistanceRelatively short(1 – 100 meters)Relatively High(1 – 100,000 meters)Immunity to EMI and RFILowHigh(Completely immune)Immunity to electrical hazardsLowHigh(Completely immune)Media and connector costsLowestHighestInstallation skills requiredLowestHighestSafety precautionsLowestHighest Networking 47 • IEEE 802.11 standards• Commonly referred to as Wi-Fi.• Uses CSMA/CA• Variations include:• 802.11a: 54 Mbps, 5 GHz• 802.11b: 11 Mbps, 2.4 GHz• 802.11g: 54 Mbps, 2.4 GHz• 802.11n: 600 Mbps, 2.4 and 5 GHz• 802.11ac: 1 Gbps, 5 GHz• 802.11ad: 7 Gbps, 2.4 GHz, 5 GHz, and 60 GHz• IEEE 802.15 standard• Supports speeds up to 3 Mbps• Provides device pairing over distances from 1to 100 meters.• IEEE 802.16 standard• Provides speeds up to 1 Gbps• Uses a point-to-multipoint topology to providewireless broadband access. Networking 4825/09/201725 StandardMaximumSpeedFrequencycompatible Backwards802.11a54 Mbps5 GHzNo802.11b11 Mbps2.4 GHzNo802.11g54 Mbps2.4 GHz802.11b802.11n600 Mbps2.4 GHz or 5 GHz802.11b/g802.11ac1.3 Gbps(1300 Mbps)2.4 GHz and 5.5GHz802.11b/g/n802.11ad7 Gbps(7000 Mbps)2.4 GHz, 5 GHz and60 GHz802.11b/g/n/ac Networking 4925/09/201726 When selecting the infrastructure cabling, some consideration maybe required to choose the type of cables ConsiderationNotesInstallationlogisticsHow easy is the cable to install and work with?Is security a main concern?ShieldingWill the cabling run near “noisy” areas, such as power lines or motors?Is crosstalk a major concern?Transmission rateHow fast does the network need to transmit data?Will the speed support growth in the future?Signal attenuationHow far does the cable need to run?CostWhat is the budget for cabling? Networking 51 RepeaterCopies bits from one network to anotherDoes not look at any bitsAllows the extension of a network beyondPhysical length limitationsHigherLayersPhysicalHigherLayersPhysical PhysicalRepeaterNetwork A Network BNetworking 5225/09/201727 Hubs Extends max distance between nodes Backbone Hub (Repeater) interconnects LAN segments The individual segment collision domains become one large collisiondomain if a node in CS and a node in EE transmit at same time: collisionNetworking 53 Bandwidth is the raw capability of a communications channel tomove data through that channel. Typically measured in bits or bytesper second (or some, possibly large, multiple thereof). May also bemeasured in hertz. How fast a device can send data on a single cable. Throughput is the total capability ofa processing system to moveproduct through that system. How many hits (bits) are actuallytransferred between two computersNetworking 5425/09/201728 Data Link LayerData link layer attempts to provide reliable communication overthe physical layer interface.Breaks the outgoing data into frames and reassemble thereceived frames.Create and detect frame boundaries.Handle errors by implementing an acknowledgement andretransmission scheme.Implement flow control.Supports points-to-point as well as broadcast communication.Supports simplex, half-duplex or full-duplex communication.Networking 55 NetworkDataLinkLLC SublayerMAC SublayerPhysical 802.3 Ethernet802.11 Wi-Fi802.15 BluetoothLogical LinkControlNetworking 5625/09/201729Networking 57The MAC address, also called the Ethernet, physical,hardware or adapter addressThe MAC address can be obtained from computers operatingunder Microsoft Windows by typing the ipconfig /all commandwhile in the command mode.The MAC address is 6 bytes (48 bits) in length The address is displayed in 12 hexadecimal codes. The first 6hexadecimal codes are used to indicate the vendor of thenetwork interface, also called the Organisationally UniqueIdentifier (OUI)Networking 5825/09/201730 The last 6 hexadecimal values are unique numbers assigned by the vendor. IEEE is the worldwide source of registered OUIs. Company ID / Vendor Serial #Manufacturer00-AA-00-B6-7A-57Intel Corporation (00-AA-00)00-00-86-15-9E-7AMegahertz Corporation (00-00-86)00-50-73-6C-32-11Cisco Systems, Inc. (00-50-73)00-0A-27-B7-3E-F8Apple Computer Inc. (00-0A-27)00-00-86-15-9E-7AMegahertz Corporation (00-00-86) Networking 59 A data frame is used to transport data across the networkpp. 78-85Networking 6025/09/201731Preamble consists of sevenbytes all of the form10101010, and is used by thereceiver to establish bitsynchronisationStart frame delimiter is asingle byte, 10101011,which is a frame flag,indicating the start of aframeThe MACaddresses usedin 802.3 arealways 48 bitslongLength/Type field is theindicates the number ofbytes of data (0 to 1500bytes).Frames size must be min46 bytes, not including thepreamble, if data is lessthan 46 bytes, the Pad fieldwill compensatedData: This is the databeing transferred from thesource to the destinationand destination to thesource4 byteChecksum fielduses a CRC-32polynomialcode(dest. MACthrough to Pad)Networking 61Networking 6225/09/201732 StandardorganisationNetworking StandardsIEEE• 802.2: Logical Link Control (LLC)• 802.3: Ethernet• 802.4:Token bus• 802.5: Token passing• 802.11: Wireless LAN (WLAN) & Mesh (Wi-Fi certification)• 802.15: Bluetooth• 802.16: WiMaxITU-T• G.992: ADSL• G.8100 – G.8199: MPLS over Transport aspects• Q.921: ISDN• Q.922: Frame RelayISO• HDLC (High Level Data Link Control)• ISO 9314: FDDI Media Access Control (MAC)ANSI• X3T9.5 and X3T12: Fiber Distributed Data Interface (FDDI) Networking 63 Switch-Bridge (L2) Stores and forwards Ethernet frames Examines frame header and selectively forwards frame based on MAC destaddress When frame is to be forwarded on a segment, uses CSMA/CD to accesssegment Transparent (hosts are unaware of presence of bridges) plug-and-play, self-learning (bridges do not need to be configured)HigherLayersPhysicalHigherLayersPhysical 1 PhysicalBridgeData Link23-01-88-A8-77-45Physical 2Data Link Data LinkData Link53-F1-A4-AB-67-4FNode in Network ANode in Network BNetworking 6425/09/201733 The networking protocol used in most modern computer networks isEthernet. Ethernet is a CSMA/CD LAN protocolCS – Carrier SenseMA – Multiple AccessCD – Collision Detection The information in an Ethernet network is exchanged in a Frame The Frame provides grouping of the information for transmission.Networking 65Networking 6625/09/201734Networking 67 Network LayerImplements routing of frames (packets) through the network.Defines the most optimum path the packet should take from thesource to the destinationDefines logical addressing so that any endpoint can beidentified.Handles congestion in the network.Facilitates interconnection between heterogeneous networks(Internetworking).The network layer also defines how to fragment a packet intosmaller packets to accommodate different media.Networking 6825/09/201735 Switch-Bridge (L3) Stores and forwards Ethernet frames examines frame header and selectively forwards frame based on IPdest address when frame is to be forwarded on a segment, uses CSMA/CD to accesssegment Can be configured to create a VLAN Transparent hosts are unaware of presence of switchNetworking 69RouterHigherLayersPhysicalHigherLayersPhysical 1 PhysicalRouterData LinkPhysical 2Data Link Data LinkA node in Network AA node in Network BData LinkNetwork145.65.23.102Network137.22.144.6Network NetworkNetworking 7025/09/201736Transport LayerPurpose of this layer is to provide a reliable mechanism for theexchange of data between two processes in differentcomputers.Ensures that the data units are delivered error free.Ensures that data units are delivered in sequence.Ensures that there is no loss or duplication of data units.Provides connectionless or connection oriented service.Provides for the connection management.Multiplex multiple connection over a single channel.Networking 71 Session LayerSession layer provides mechanism for controlling the dialogue betweenthe two end systems. It defines how to start, control and endconversations (called sessions) between applications.This layer requests for a logical connection to be established on an enduser’s request.Any necessary log-on or password validation is also handled by thislayer.Session layer is also responsible for terminating the connection.This layer provides services like dialogue discipline which can be fullduplex or half duplex.Session layer can also provide check-pointing mechanism such that if afailure of some sort occurs between checkpoints, all data can beretransmitted from the last checkpoint.Networking 7225/09/201737Presentation LayerPresentation layer defines the format in which the data is to be exchangedbetween the two communicating entities.Also handles data compression and data encryption (cryptography). Application Layer Application layer interacts with application programs and is thehighest level of OSI model.Application layer contains management functions to supportdistributed applications.Examples of application layer are applications such as file transfer,electronic mail, remote login etc. Networking 73Burgess, M., 2003. Principles of Network and System Administration. 2nd ed.Chichester: John Wiley and Sons Ltd.Hallberg, B., 2005. Networking: A Beginner’s Guide. 4th ed. Osborne: Mcgraw-Hill.Limoncelli, T. & Hogan, C., 2001. The Practice Of System and NetworkAdministration. London: Addison-Wesley.Lowe, D., 2005. Networking All-In-One Desk Reference For Dummies. 2nd ed. NewYork: Hungry Minds Inc..Olifer, N. & Olifer, V., 2005. Computer Networks: Principles, Technologies AndProtocols For Network Design. Chichester: John Wiley And Sons Ltd.Stallings, W., 2003. Data And Computer Communications. 7th ed. New York:Prentice Hall.Subramanian, M., (2000). Network Management: An Introduction to Principles andPractice. Chichester: Addison-Wesley.Tanenbaum, A., 2002. Computer Networks. London: Prentice Hall Ptr.JournalsThe Institute of Engineering and TechnologyNetworking 7425/09/201738 Structuring an introductory paragraph1Introduce the context or background to the topic: Perhaps you couldexplain the title in your own words or use a quotation from an author whooffers a supporting or contradictory statement about your topic area.2What is the purpose of writing about this topic?Is there a problem orcontroversy with the topic?3Definitions: Are you using any complex terminology or acronyms thatneed defining? Try to use a working definition from an expert in yoursubject area rather than referring to a general dictionary definition.4Introduce the main ideas that stem from your topic: You cannot writeabout everything; for a 2,000 word assignment, select between 3-5 keyideas and introduce them in the precise order in which they will bediscussed. Networking 75


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