CHAPTER 15 NETWORK ANALYSIS, DESIGN, AND IMPLEMENTATION

Members Group :

Nurul Farhha Bt Rosland

Nurul Izzah Bt Mat Sanidon

Wan Aznie Bt Wan Ali

Yuzniza Bt Yunus

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Network Development Life Cycle (NDLC)

What ? A set of strategies for upgrading (or totally

replacing) an organization’s network system. Derived from a well established system, the

system development life cycle (SDLC), generic methodology for developing any system

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Cont…

There’s several reason why SLDC is different with NLDC :

Network system needs to be replaced more frequently

Network system expands more rapidly Cost of network installation is decreasing

continuously

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Cont..

Based on the differences, the network designer has agreed that SLDC should be replaced by NLDC because NLDC:

Development process take less time The cost of the process must be less to justify

the frequency

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Differences SLDC and NLDC

Has 5 phases Planning Analysis Design Implementation Maintenance

Has 2 phases: Analysis Design ImplementationRemove:

• Planning : long and expensive phase

• Maintenance : not included in network designer task

SLDC NLDC

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1. Analysis Phase

Analysis phase in network development life cycle (NDLC) is made of 2 major steps :

analysis of the existing system (baselining) analysis of the needs for the new network

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1.1 Baselining

Baselining is the measurement and recording of characteristics and features of the existing network system over a specific period of time.

This is several study analyst must do : System users System nodes Protocols Application programs Network traffic

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Cont..

System Users - baselining usually the measurement of system users (average, peak and maximum). Other measurement is the types of applications used, the number of hours system used, and the level of utilization.

System Nodes- the information collected about system nodes include the number of nodes, type of nodes, logical location of nodes , serial number and etc.

Protocols- contain the type of protocol for example TCP/IP, the version, the computer on which it is installed, and level of utilization.

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Cont..

Application Programs- contain the type of application, the computer on which it is installed and frequency of utilization.

Network Traffic- the most important measurement in baselining is the collection of network traffic information. Carefully measure and record needs for: Throughput (average and peak) Frame size (average and maximum) Number of frames per second (average and peak) Number of collisions (average and peak) Number of dropped frames due to error detection

(average and peak) Number of dropped frames due to congestion (average

and peak)

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1.2 Need Analysis

Defines the characteristics of the new proposed network system.

Have 2 separate activities : Scope needs analysis User needs analysis

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Cont..

Scope needs analysis defines the logical layout of the new network system. The analysis composed of 3 parts :

Local networks Backbones Global access

Local Networks- these are the network will connect internal user (desktop computers inside a building or on a floor) to the network system.

Backbones Network- connect local networks to create a network system for the organization.

Global Connection- part of the network system and part of the baseline analysis.

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Cont..

User needs analysis must be carefully evaluated. \ A user needs :

Hardware resources Software resources Bandwidth

Hardware Resources- runs an application program (desktop computer, printer, storage device-hard drive).

Software Resources- perform a task (application programs and data).

Bandwidth- downloads the application program and data.

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2. Design Phase

Uses the information collected during the analysis phase to create specification for the new network system.

Four major activities: Upper Layer Protocols Lower Layer Protocols Hardware Global Connection / Internet

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2.1 Upper Layer Protocols

Protocol to be run on network system involves two steps:

I. Defining the protocol suite Choices: TCP/IP, Windows 2000, Novell Decision based on factors such as

Application to be used Type of equipment needed Type of interaction between the nodes

II. Defining the types and location of servers selection of the application layer protocols where they should be installed Ex: if TCP/IP protocol suite is chosen in previous step. The

designer may choose to use: SMTP and POP to handle e-mail TELNET to handle login FTP to handle file transfer

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2.2 Lower Layer Protocols

Depends on the capacity needs of each network. Capacity of networks is the number of bits per

second each network can handle. Information collected during baselining and user

needs analysis - determine the capacity of network.

Choice of capacity automatic defines the protocol to be used at lower layers.

Ex: capacity of 100Mbps = 100BASE-T Decision about each local network and the

backbone need, not be the same.

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2.3 Hardware

Type and number of computer needed - Information collected during base lining and user needs report.

Type and number of hardware pieces required to create a network – information obtain from scope needs report and lower layer protocols.

Ex: 10BASE-T for a network with 20 users, a hub with at least 20 ports is needed.

Types of transmission medium is UTP Scope need analysis – length of the cable needed

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2.4 Global Connection

How organization connected to other organization or other sites of the same organization?

Depends on factors including: Needs for security Total capacity Bandwidth of the backbone

Ex: T-1 Line

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3. Implementation Phase

STEPSIMPLIMENTAT

IONPHASE

PURCHASING OR RENTING NEW HARDWARE & SOFTWARE

INSTALLATION OF NEW HARDWARE & SOFTWARE

TRAINING OF USERS

TESTING OF THE SYSTEM & DOCUMENTATION

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New hardware or software can either be done by internal staff the vendor specialists or a third party

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USER TRAINING

Training in accessing the system and the use of the new hardware

Need to know the benefits of the upgrade

Can be trained individually or in groups based on level

21 TESTING

After the users are trained , the system is tested.Tested can be done by monitoring the system.

Identify error and problem.

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DOCUMENTATION

To maintained efficiently.

User Documentation- Users need to know the commands, potential

problems, the person to call

in case of malfunction

SYSTEM DOCUMENTATI

ONCan be

maintenance and must be

system documentation for 3 phases

system