Chapter 1: Introduction to Client/Server IS zLAN zLAN Hardware Components zLAN Software Components...

Chapter 1: Introduction to Client/Server IS LAN LAN Hardware Components LAN Software Components LAN Connectivity Client/Server IS (C/S IS) Effective Analysis, Design and Implement of C/S IS C/S Connectivity and Compatibility C/S Analysis - business oriented Paradigm Shift Logical Architecture of C/S Physical Architecture of C/S

Local Area Network

Limited to a geographical areaowned, administrated and used by a

single organization (not subject to FCC regulations)

support moderate data transfer rates with lower error rates

supports full connectivity among WS

LAN Hardware Components

Network Interface CardServer - typesWorkstationHub, MAU, Concentrator, SwitchConnectorCable UPS

LAN Software Components

Network Operating SystemBackup SoftwareWorkstation System SoftwareNetwork Application Programs

LAN Connectivity

Client/Server Information Systems

Client/Server Information System Distributed IS

Organization’s Success right information right end user right format right place and time right price

Benefits of C/S IS

Resource Sharing Communication

GroupWare Management Control Reduced Costs - downsizing Support business environmental changes Improved Information Accessbility Faster/Better Information Open Architecture - Compatibility Issues Empowered Users

Problems of C/S IS

Transition CostsHigh cost of training, supportMultivendor architectureLack of management tools for distributed

environmentLack of standardsTechnology not ready for missing critical

applicationLack of software conversion tools

Effective Analysis, Design, & Implmentation of

C/S(1): Top-Down Approach

GOLDMAN: CSIS FIG. 01-03

APPLICATION

DATA

NETWORK

TECHNOLOGY

BUSINESS

RE

QU

IRE

ME

NT

S

SO

LU

TIO

NS

Top-Down Approach:

Business identifying business-level objectives strategic business planning BPR

Application identifying information need relating information needs to business

process & opportunities

Top-Down Approach: Effective Analysis, Design, & Implmentation of C/S(2)

Data identifying data collection and distribution data modeling

Network network analysis & design physical location data data characteristics & compatabilities data transfer

Technology technology analysis

Top-Down Approach

Business

ApplicationDataNetwork

Technology

Business Requirements/Functions

Application DesignDatabase DesignNetwork Model

Logical Network Design

Technology Model Physical Network Design

Client/Server Connectivity and Compatibilities Issues

The OSI Model Application Presentation Session Transport Network Data Link Physical

Business-Oriented Client/Server Analysis

User Issues # of users, their activities, security, support

Local Communication required speed, distance to cover

Resource Sharing # of printer, modems, etc

File Sharing # of concurrent users

Business-Oriented Client/Server Analysis

Distributed Data Access database partition & allocation

Client/Server IS Management/Administration personnel training

Extended Communication internetworking

Paradigm Shift


Mainframe Front-end processor

Cluster controller

SYSTEMS ARCHITECTURE

PA

RA

DIG

M I

AG

E O

F T

HE

MA

INF

RA

ME

PA

RA

DIG

M II

INT

RO

DU

CT

ION

OF

TH

E P

ER

SO

NA

L C

OM

PU

TE

R

PA

RA

DIG

M III

DA

WN

OF

TH

E C

LIE

NT

/SE

RV

ER

AR

CH

ITE

CT

UR

E

Host-based development and operations.

PEOPLE ARCHITECTURE

Centralized MIS departments Specialization in

Application development Systems analysis Systems programming SNA network support

Centralized MIS departments Development of departmental PC expertise Beginning of debate, "Whose information is this?"

MIS department's? User department's?

Dawn of the empowered user Cross-functional, department-based applications development MIS personnel in consultative roles Changing role of centralized MIS department

Simultaneous development and operation of departmental LANs.

PCPC

PARADIGM SHIFT

Mainframe as corporate super-server

Departmental servers

Distributed computing on multivendor systems delivering transparent interoperability

Client PCs

PARADIGM SHIFT

3270

3270

PC PC

Enterprise Network


Cluster controller

Host-based development and operations.

3270

3270

People Architecture

Dawn of empowered userCross-functional, user department-

based application developmentMIS personnel in consultative rolesChanging role for centralized MIS

department

Logical Architecture of C/S IS

PAD Architecture Presentation (User Interface) Application (Processing) Data (Data Manipulation)


Presentation

Application

Data

Communication

Presentation Logic

Interfaces to Presentation GUI

Business Logic Actual Program

Rules

Database Logic Interfaces to DBMS

in Data Layer

Presentation Logic

Interfaces to Presentation GUI

Business Logic Actual Program

Rules

Database Logic Interfaces to DBMS

in Data Layer

Presentation

Application

Data

CLIENT SERVER

Figure 1-11 Presentation-Application-Data Logical Model


Presentation

Application

Data

Client Only Cooperative Client

and Server

Server Only

Host-Based Presentation

(Remote Presentation, Dumb Terminals)

Host-Based Processing

Host-Based Data Management

(Remote Data Management)

Distributed Presentation (Cooperative Presentation)

Distributed Computing (Cooperative Computing, Cooperative Processing)

Database Distribution

(Distributed Data

Management, Distributed Database)

Client-Based Processing

Pre

se

nta

tio

n -

Ap

plic

atio

n -

Da

ta

LA

YE

R

Executing Platforms

Client-Based Data Management

(Local Data Management)

Client-Based Presentation (Client GUI,

Local Presentation, GUI Veneer)

Figure 1-12 Potential Categories of Elements of Client/Server Information Systems

Characteristics of C/S IS

Client-based Presentation


Host-Based Processing


Host-Based ProcessingCategory of Client/Server Information Systems

Dis

trib

ute

d

Co

mp

utin

g

Dis

trib

ute

d

Da

ta M

an

ag

em

en

t

Co

op

era

tive

Pro

cess

ing

Client-Based Processing


Client-Based ProcessingCategory of Client/Server Information Systems

Data Management

Processing

Presentation

Processing

Data Management

Client-Based Presentation

Figure 1-13 Presentation + Processing + Data Management = Logical Client/Server Architecture


Transparency

GOLDMAN: CSIS FIG: 01-15

Transparency: Clients and servers cooperatively share processing load without regard for operating system or protocol differences.

VAX AS/400 RS/6000 Netware Mainframe UNIX

Se

rve

rsC

lie

nts

Enterprise Network

Mac UNIX Windows

Scalability: Additional clients are added to system with little or no effect on processing load owing to incremental processing power added by each client.

DOS OS/2

Original Clients Additional Clients

ProcessingProcessingProcessingProcessingProcessingProcessing

ProcessingProcessingProcessingProcessingProcessing

DOS OS/2

ProcessingProcessing


Se

rve

rsC

lie

nts

Enterprise Network

Mac UNIX WindowsDOS OS/2



TransparencyMiddleware


Scalability


Transparency: Clients and servers cooperatively share processing load without regard for operating system or protocol differences.


Se

rve

rsC

lie

nts

Enterprise Network

Mac UNIX Windows

Scalability: Additional clients are added to system with little or no effect on processing load owing to incremental processing power added by each client.

DOS OS/2

Original Clients Additional Clients



DOS OS/2

ProcessingProcessing


Se

rve

rsC

lie

nts

Enterprise Network

Mac UNIX WindowsDOS OS/2



TransparencyMiddleware


Interprocess Communication


SERVER A SERVER BCLIENT PC

Distributed Application

BACK ENDS or ENGINESFRONT-END


Client Process Server

ProcessServer

Process


Figure 1-16 Distributed Processing Requires Interprocess Communications

Database Distribution




Serv

ers

Cli

en

ts Mac UNIX WindowsDOS OS/2

Front-end tools

Database connectivity

software

Front-end tools


software

Front-end tools


software

Front-end tools


software

Front-end tools


software

Distributed DBMS


software

Distributed DBMS


software

Distributed DBMS


software

Distributed DBMS


software

Distributed DBMS


software

Distributed DBMS


software

Enterprise Network

Database Transparency

Universal Data Access

System

Single Solution Gateway

Figure 1-17 Key Components of Database Distribution


Distributed Transaction Processing


Local TP Monitor

Distributed Processing

Distributed Data Management

Client-Based Presentation

Local TP monitors ensure integrity of local transaction postings.

Distributed TP monitor ensures integrity of overall distributed postings.

Distributed TP monitor and local TP monitor communicate via DTP API.

Local TP Monitor

Local TP Monitor

Distributed Transaction Processing Monitor

Transaction Processing

Monitor

Presentation

Application

Data

Management

Inte

r-P

rocess C

om

munic

ation

All software installed on same system.

Logical Model of Distributed Transaction Processing MonitorLogical Model of Local or

Nondistributed Transaction Processing Monitor

All

postings d

one a

nd m

onitore

d locally

CLIENT SERVER A SERVER B

DTP

API

DTP

API

DTP

API





Figure 1-19 Local versus Distributed Transaction Process Monitoring


Business

Application

Data

Network

Technology

Increased competition on a global scale Corporate downsizing Information systems downsizing Business process redesign/reengineering

Client presentation Application rightsizing Distributed computing Distribute applications

Distributed databases

Enterprise networks Distributed network management

To be determined by physical client-server design

D

istribu

ted

Tra

nsa

ction

Pro

cess M

on

itors

Mid

dle

wa

re

Inte

rpro

cess C

om

mu

nica

tion

C

lien

t/Se

rver A

rchite

cture

Figure 1-20 The Top-Down Model and Logical Client/Server Architecture

Physical/Technology Architecture

Client/Server Architecture vs. Mainframe/Terminal Architecture


Formatting of data for presentation to user

Application program request for data

Data retrieval Data storage

Transport of data requests Transport of actual data

Presentation of data to userMainframe Network Terminal

Mainframe - Terminal




Presentation of data to user Formatting of data for

presentation to user Application program request

for data Data retrieval Data storage Transport of data requests Transport of actual data

Server Network Client Workstations

Client/Server


Cluster controller

3270 Terminals

Server Clients

Network

Hub

Network

3270

3270

Figure 1-21b Client/Server versus Mainframe-Terminal Architectures


Formatting of data for presentation to user




Presentation of data to userMainframe Network Terminal

Mainframe - Terminal




Presentation of data to user Formatting of data for

presentation to user Application program request

for data Data retrieval Data storage Transport of data requests Transport of actual data

Server Network Client Workstations

Client/Server


Cluster controller

3270 Terminals

Server Clients

Network

Hub

Network

3270

3270Figure 1-21a Client/Server versus Mainframe-Terminal Architectures

Figure 1-23 Example of an Enterprise Network Physical Topology

router

Minicomputer configuration

Mainframe configurationEthernet LAN

Token-Ring LAN

LAN

to

LAN

S

ervi

ces


Frame Relay WAN services

Internet Services

router

router

router

Two Tierd vs. Three-Tiered CS Architecture

Two-tierdThree-tierd

Figure 1-24 Two-Tiered versus Three-Tiered Client/Server Architecture


Fat Client Fat Server

TWO-TIERED ARCHITECTURE

THREE-TIERED ARCHITECTURES

Presentation Logic

Database Logic

Middleware

CL

IEN

TS

TIE

R 1

TIE

R 2

DE

PA

RT

ME

NTA

L

SE

RV

ER

S

TIE

R 3

SU

PE

R-S

ER

VE

RS

M

AIN

FR

AM

ES

Business Logic

Database Logic

Business Logic

Presentation Logic Presentation Logic

Business Logic

Database Logic

Chapter 1: Introduction to Client/Server IS zLAN zLAN Hardware Components zLAN Software Components...

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Transcript of Chapter 1: Introduction to Client/Server IS zLAN zLAN Hardware Components zLAN Software Components...