chapter 1: introduction to client/server is zlan zlan hardware components zlan software components...
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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
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
GOLDMAN: CSIS FIG. 01-09
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
Mainframe Front-end processor
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)
GOLDMAN: CSIS FIG. 01-11
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
GOLDMAN: CSIS FIG. 01-12
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
GOLDMAN: CSIS FIG. 01-13
Host-Based Processing
Host-Based Data Management
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
Host-Based Data Management
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
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
VAX AS/400 RS/6000 Netware Mainframe UNIX
Se
rve
rsC
lie
nts
Enterprise Network
Mac UNIX WindowsDOS OS/2
ProcessingProcessingProcessingProcessingProcessingProcessing
ProcessingProcessingProcessingProcessingProcessing
TransparencyMiddleware
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
VAX AS/400 RS/6000 Netware Mainframe UNIX
Se
rve
rsC
lie
nts
Enterprise Network
Mac UNIX WindowsDOS OS/2
ProcessingProcessingProcessingProcessingProcessingProcessing
ProcessingProcessingProcessingProcessingProcessing
TransparencyMiddleware
GOLDMAN: CSIS FIG. 01-16
SERVER A SERVER BCLIENT PC
Distributed Application
BACK ENDS or ENGINESFRONT-END
Interprocess Communication
Client Process Server
ProcessServer
Process
Interprocess Communication
Figure 1-16 Distributed Processing Requires Interprocess Communications
GOLDMAN: CSIS FIG: 01-17
VAX AS/400 RS/6000 Netware Mainframe UNIX
Serv
ers
Cli
en
ts Mac UNIX WindowsDOS OS/2
Front-end tools
Database connectivity
software
Front-end tools
Database connectivity
software
Front-end tools
Database connectivity
software
Front-end tools
Database connectivity
software
Front-end tools
Database connectivity
software
Distributed DBMS
Database connectivity
software
Distributed DBMS
Database connectivity
software
Distributed DBMS
Database connectivity
software
Distributed DBMS
Database connectivity
software
Distributed DBMS
Database connectivity
software
Distributed DBMS
Database connectivity
software
Enterprise Network
Database Transparency
Universal Data Access
System
Single Solution Gateway
Figure 1-17 Key Components of Database Distribution
GOLDMAN: CSIS FIG. 01-19
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
Distributed Processing
Distributed Processing
Distributed Data Management
Distributed Data Management
Figure 1-19 Local versus Distributed Transaction Process Monitoring
GOLDMAN: CSIS FIG. 01-20
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
GOLDMAN: CSIS FIG. 01-21
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
Application program request for data
Data retrieval Data storage
Transport of data requests Transport of actual data
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
Mainframe Front-end processor
Cluster controller
3270 Terminals
Server Clients
Network
Hub
Network
3270
3270
Figure 1-21b Client/Server versus Mainframe-Terminal Architectures
GOLDMAN: CSIS FIG. 01-21
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
Application program request for data
Data retrieval Data storage
Transport of data requests Transport of actual data
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
Mainframe Front-end processor
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
GOLDMAN: CSIS FIG. 01-23
Frame Relay WAN services
Internet Services
router
router
router
Figure 1-24 Two-Tiered versus Three-Tiered Client/Server Architecture
GOLDMAN: CSIS FIG. 01-24
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