NETWORK DESIGN (REKABENTUK RANGKAIAN) TJ3054LECTURER: KHAIRUL NAJMY ABDUL RANIROOM NO: STM 201OFFICE PHONE NO: 04-928 3724E-MAIL ADDRESSES: najmy@e-web.uum.edu.myOR khairul_najmy@yahoo.com HOMEPAGE: http://www.angelfire.com/mo3/najmy

Overview of computer networkingWhat is a computer networking?An interconnected collection of autonomous computer.2 or more computers are said to be interconnected if they are able to exchange (transmit/receive) information.Autonomous means that acting independently.What is a distributed system?The existence of multiple autonomous computers, which are not visible to the user.The distinction between CN and a DS lies with the SW (NOS) rather than with the HWWhy does a computer networking necessary?For organizations: Resource/Info. sharing, Saving cost, Communication medium (audio/video conferencing/net meeting), high reliability, security, scalability etc.For society: Remote access, Person-to-Person communication (e-mail/messenger/chat), audio/video conferencing etc.

Overview of computer networkingComputer networking can be classified based on type of transmission technology and scale.2 types of transmission technology, which are [1] Broadcast Network [2] Point-to-Point Network.Broadcast Network have a single communication channel that is shared by all the network devices.Broadcasting: A packet is transmitted, received and processed by each network machines/devices.Multicasting: A packet is transmitted, received and processed by a subset of the network machines/devices (e.g. stmnet, studnet etc.)Point-to-Point Network consist of many connections between individual pairs of machines.

Overview of computer networkingComputer networking scale:Local Area Network (LAN): Privately owned networks within a single building or organization or campus of up to a few kilometers in size. (10 m to 1 km inter-processor distance).Metropolitan Area Network (MAN): A bigger version of LAN and normally used similar technology covering a group of nearby corporate offices/ a city either private or public (up to 10 km inter-processor distance).Wide Area Network (WAN): Spans a large geographical area, often a country or continent (100 km to 1000 km inter-processor distance).Wireless Networks: Apply antennas, telephone with analog modem and Cellular Digital Packet Data (CDPD) service. Emerging technology: Bluetooth, GSM and GPRS.Internet: a collection of homogonous interconnected networks.

Overview of computer networkingVital CN hardware devices includes host computer, front-end processor (FEP), modulator/demodulator (modem), and terminal.Host computer: Center computer/processor within a large data communication system. It can be a mainframe or a minicomputer or a microcomputer.FEP is a special purposed computer, which can be programmed to control and process data in a network. It can be either a non-programmable and hardwired communication control unit OR a programmable device operating as a communication input/output and processor. FEP components are channel interface, SW, and line interface unit. FEP purposes are offloading certain processing/controlling data from host computer to a programmed processor, comm. line control, error control, multiplexing, converting protocol/code and etc.

Overview of computer networkingModem transforms digital electrical pulse (generated by computer/terminal) to analog signal before being transmitted via analog voice grade circuit and vice versa.Terminal is a input/output HW located at the communication circuit end points. It can be microcomputer or workstation or video terminal or teleprinter terminal or dumb/intelligent terminal and etc.Other necessary HW devices that make network becomes faster, more reliable and more secure are MUX, protocol converter, HW encryption devices, intelligent controller, line adapter and etc.HW equipments that are commonly used in LAN are server, repeater, bridge, router, gateway, and cabling.

Overview of computer networkingSeveral issues have to be touched when discussing network SW, which is highly structured.Protocol hierarchiesNetwork is arranged on the layer basis. Every layer will give services to its upper layer. Every layer communicate with its peer layer (same level) at other computer. In this case, a protocol (an agreement on how peer communication should be made) is required. Interface and ServicesEntity: Active element in each layer.SAP: The point where service can be obtained.TypesConnection-oriented: Establish, use and release.Connectionless: Each packet is routed independently.QoSReliable (acknowledged) OR Unreliable (not acknowledged)

Overview of computer networking2 reference models: Open Systems Interconnection (OSI) and Transmission Control Protocol/Internet Protocol (TCP/IP).The OSI deals with connecting open systems (open for comm. with other systems).The OSI has 7 layers:Physical: mechanical, electrical, functional, proceduralData link: error & flow control: intermediate nodeNetwork: routing, switching, network addressingTransport: error & flow control, packetizing: end-to-endSession: establish communicationPresentation: format, compression, encryptionApplication: application protocols

Overview of computer networkingFormat dataHantar melphysical portencriptionaddressingMod dialogElectrical voltageswitchingSignal mana hantar dulucompressionError controlFlow controlBerapa laju hantar electrical voltage

AplikasiPresentationSessionTransportNetworkData LinkPhysical

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(Application layer)

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(Session layer)

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Komputer Y YYYYYXXXaYXYFungsi-Fungsi Lapisan OSI

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Bertanggungjawab terhadap penghantaran bit-bit data.

Menakrifkan spesifikasi mekanikal, elektrikal, fungsian dan prosedur penghantaran bit-bit data.

Biasanya dilaksanakan secara perkakasan

Contoh piawaian pada lapisan ini adalah RS-232-C dan RS-449.

Aplikasi A di

Komputer X Fungsi-Fungsi Lapisan OSI

Lapisan Fizikal

Bertanggungjawab terhadap penghantaran bit-bit data.

Menakrifkan spesifikasi mekanikal, elektrikal, fungsian dan prosedur penghantaran bit-bit data.

Biasanya dilaksanakan secara perkakasan

Contoh piawaian pada lapisan ini adalah RS-232-C dan RS-449.

Media Penghantaran

RANGKAIAN KOMUNIKASI

Overview of computer networkingThe OSI principles:Each layer can be implemented independentlyEach layer communicates with its peer layer (same level)Each layer needs service provided by bottom layer esp. related to primitive functions.In the real world:There is almost no OSI product.In LAN, the 2 most bottom layer used LAN standard.In WAN, the 3 most bottom layer used X.25, ATM and FR

Overview of computer networkingTCP/IP has 4 layers:Network interface/physical communication: Connects the network using some protocol so it can send/receive IP packet over it.Internet (IP): Permits hosts to injects packet into any network and have them travel independently to the destination. This layer defines an official packet format and protocol known as Internet Protocol (IP).Transport (TCP/UDP): Allows peer entities on the source and destination hosts to do conversation. Transmission Control Protocol (TCP) is a reliable connection-oriented protocol that allows a byte stream originating on one machine to be delivered without error to any other machine in the Internet. User Datagram Protocol (UDP) is an unreliable connectionless protocol that do not want TCP sequencing or flow control.

Overview of computer networkingApplication: Contains all the higher level protocols, such as virtual TELNET, FTP, SMTP, POP3, DNS, HTTP and etc.

SNA

IPX/ SPX

Apple-Talk

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ApplicationTCP/UDPIPPhysical Communication

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Overview of computer networkingStandard can affluence the current network design and implementation, such as tackling problems related to HW and SW.Standard are usually enacted/regulated by vendors, users and ISPs OR NSPs.Standard are usually drafted by certain committee, which some of the members are vendor representatives Standard can be either de jure or de facto.de jure: is being enacted by formal/official bodies, such as IEEE, ISO, ANSI etc.de facto: is being established by informal organization, such HW/SW manufacturers like Microsoft, IBM etc.ISO is being represented by 90 countries dealing with a lot of standard subjects.

Intro. of system approach in network designActually, there are a lot of approach types can be made in designing a new network or in upgrading an existing network.In this course, the system approach is being chosen to design a network or to upgrade an existing network.The system approach can be used by network designer in: [1] planning a new data communication network [2] troubleshooting or upgrading the performance of a current network [3] planning a public data network.In designing a network, all the affluence factors and limitations/problems should be clarified and highlighted their effects on the network performance.The key of success starting from a good and effective planning particularly, based on fulfilling the system user interface requirement

Intro. of system approach in network designCurrently, network designer usually emphasizes on user application system. In this case, 2 types of network user should be classified, which are organization management (e.g. manager/director/employer) and individual user (e.g. employee/subordinate).Manager needs a reliable network so that they believe whatever messages that they receive.User needs a consistent/stable network so that they can keep maintaining/upgrading their productivities.There are 13 basic steps used in network design.Feasibility StudyThe main purpose is to improve the current network or to build entirely a new network for organization/public.

Intro. of system approach in network designFeasibility Study (Continued)The responsibility is to define clearly the problem existed and make it as (a) written document. In the document, highlight the problems, possible root causes, possible counter measures (solutions) that can be offered and the objective/benefits of building a new network. Besides, state also the complete and realistic costs for a newly designed network or accurate costs/benefits comparison for an upgraded network.Prepare a Network Design Plan(s)The main purpose is to provide a framework(s) for the network design plan. Ensure that the plan meets the requirements. Identify also possible constraints. Besides, enlist functions that newly upgraded/designed network can perform.

Intro. of system approach in network designUnderstand the current/existing networkTry to know fully attributes of existing network system, such as operational functionality and HW (CPU type, memory size and configurations), SW (type applications and network drivers/NOS), protocols and standards, and operational support methods. Besides, enlist some proposed network application for future use. If possible put written ideas in terms of notes/DFD/flowchart.Define the network requirementThe purpose is to determine the what in the development of a new network and to describe attribute the network must contain. Conceptually, identify inputs, such as user needs, organizational needs, existing systems, regulations, and environment politics in order to draw out the network requirements and constraints. In details, review the org. long and short term plan.

Intro. of system approach in network designAlso, simulate the circuit capacity, reliability and processing time (response time/queuing theories). If possible, highlight future requirement(s) that may be uncovered for now.Define the geography scopeThe purpose is to identify the physical location that must be interconnected by the newly designed or upgraded network. There are 4 basic levels in mapping the network, which are International, Country, State/City, and Local Area/Facility.Analyze the messageThe purpose is to identify msg. char., no. of msg. and how to estimate volume of message. This step can be done simultaneously with step no. 5 above. The output is a list of msg. With no. of char. per msg., network link traffic table.

Intro. of system approach in network designCalculate the network traffic and circuit loadingThe purpose is to calculate the circuit capacity that is needed for traffic based on no. of char. per msg.& no. of msg. delivered per given period of time. Therefore, needs to calculate the response time / turnaround time. RIT = MIT + APT + MOT. Besides, it is possible to show the circuit capacity req. for each link. The output is the documented of traffic analysis (msg. & total of char. per day).Identify network control and securityThe purpose is to control and protect info. from various threats, such as errors & omissions, msg. Loss/damage, disasters, poor error handling, viruses/worms, unreliability etc. Use ctrl spreadsheet to identify, prepare document and re-evaluate all the ctrl point within a network. The output are ctrl spreadsheet, list of threats def. & list of ctrl methods performed.

Intro. of system approach in network designDesign network configurationThe purpose is to configure the network based on network goals/objectives.The ckt. config. is done btw. The user and host computer. The result depends on node/terminal and SW/HW changing. The output is the network config. maps/layouts and list of network goals.Consider the SW selection The purpose is to overcome the limitation resulted by terminal usage and diff. types of SW used thru the using of protocol converter/router/gateway. The output is the details of network config. Either it is PTP or Multiplexed or Multidropped or Packet switched or combinations of above. Besides, there should be a description of protocol selected as well as WAN/LAN SW documentation.

Intro. of system approach in network designConsider the HW selectionThe purpose is to get all the HW required. The HW of network can be categorized as transmission media and internetworking devices.The output is the layout and the config. (multidrop/multiplex, etc.) showing all the linked nodes. Calculate the cost requiredThe purpose is to estimate the cost of building/upgrading a network and to review the complexity of costing on the chosen network configuration. A lot of techniques can be used to estimate the cost, such as network cost analyzer, cost/benefit analysis, voice grade leased circuit cost, dial-up circuit cost, wideband analog circuit cost, digital circuit cost, T-carrier circuit cost, pkt sw. cost, HW cost, and further design cost.

Intro. of system approach in network designCalculate the cost requiredThe network cost generally can be classified into two groups, which are direct cost and indirect cost. Direct cost includes processor/server, comm. devices, common carrier line tariffs, SW/NOS, spare part cost, and maintenance cost. Indirect cost will be personnel training and disruption of normal activities. The output is a report of network expenditure generated by network cost analyzer.Implement the new networkThere will two subtasks, which are selling the proposed network to mgmt. or to client/user and implementing the network. Selling the network can be done orally to top mgmt. There are 4Ps techniques in implementing the network that are Pilot, Phased, Parallel, and Plunge.