3 Tier ClientServer (PowerPoint) by ewghwehws

VIEWS: 9 PAGES: 38

									3-Tier Client/Server


[OOPSLA 연구실]
[민 경 섭]
Case Study 1
 : U.K. Employment
 Service Rolls Out 3-Tier in
 Record Time
[OOPSLA 연구실]
[민 경 섭]
Table of Contents
 Background
 The Application
 3-Tier Architecture
 Advice
Background
 The U.K. government passed the Job Seekers Allowance legislation
 to encourage people to get jobs and move off benefit payments faster.
 To comply with this new program, the Employment Service’s staff
 quickly needed a top-notch application. They were new required to
 monitor the progress that 2.45 million unemployed people were making
 toward finding work. The IT department at Employment Service rose
 to this mammoth challenge. It rolled out a major new application -
 called the Labour Market System - in record time. It’s one of the largest
 operational client/server systems in the world.
The Application : Requirements
Employment Service is an executive agency of the Department
for Education and Employment in the U.K. Its branch offices are
located throughout England, Scotland, and Wales. The agency’s
main business is to help people without jobs find work. Currently
about 2.45 million people have registered as being unemployed.
Before the government passed the Job Seekers Allowance(JSA)
legislation, unemployed people received benefit payments if they
had previously made unemployment insurance payments, or if
they requested income support. JSA added additional requirements.
To keep receiving benefit payments, Employment Services clients
have to sign and comply with a Job Seekers Agreement. This agreement
makes them promise to apply for a certain number of jobs within a
particular time period. Staff members at the employment offices have
to log their client’s Job Seekers Agreement and job-seeking activities.
As a last resort, they can recommend that benefits payments be docked
if clients aren’t making progress.
The Application
    : Existing Systems
 OSCAR
  – log the meetings between the employment office
    staff and the people coming in to seek jobs
  – have its own data locally
 SVACS
  – show the vacancies available for jobs in the U.K.
  – have data in nine relational database
 The Benefits Payment System
  – track payments of unemployment benefits and
    allowances
The Application
    : New System
 Labor Market System(LMS)
  – N-tier client/server application
  – combine OSCAR and SVACS’s local
    information into global databases
 Job Seekers Agreement Payment
  system(JSAP)
  – extend ‘the Benefits Payment System’
  – users can access it through the LMS PCs
Architecture
 Physical architecture
  LMS server, JSA server, many LMS PCs, JSA
   Payment System, LMS Database Centers,
   dedicated 64Kbps WAN, etc
 Logical architecture
  – tier 1
     • the client s/w and Tuxedo /WS running on the PCs
       in the employment offices
  – tier 2
     • multiple LMS servers that run Tuxedo services
  – tier 3
     • four regional Ingres database
Physical architecture
Logical architecture
Advice
 Use UNIX multiprocessors so you can
  inexpensively increase processing power in small
  increments as you need it
 A TP Monitor is essential when dealing with many
  client connections
 Test, test, test at all stages of development
 Plan for the challenges of distributing s/w
  remotely to a large number of users
 Recognize that users will need on-going training
  and mentoring to exploit a new system’s fill
  capabilities
Case Study 2
 : PeopleSoft Moves
 Applications to 3-Tier

[OOPSLA 연구실]
[민 경 섭]
Table of Contents
 Background
 The Application
 3-Tier Architecture
 Advice
Background

With revenues of $450 million in 1996, PeopleSoft has built a successful
business delivering 2-tier client/server applications that run their customers’
core business functions. While these are enterprise-class applications -
mostly used by Global 2000 customers - they are typically installed as
departmental applications that support a few hundred concurrent users.
But PeopleSoft recognized that its customers were changing the way they
were using their applications. With the arrival of the Internet, many of
PeopleSoft’s customers began launching initiatives to let all their employees
access the applications. In addition, many of these customers were using
several PeopleSoft applications together
The Application : Requirements
Instead of a few hundred users in a department accessing a particular
application, tens of thousands of concurrent users will be using an entire
suite of applications.
PeopleSoft must provides a series of integrated modules that run its
customers’ core business functions. These applications will be used by
Global 2000 customers that are eighty percent of PeopleSoft customers. And
remaining small business, higher education institutions, and federal, state,
and logical governments in US and Canada will use them.
PeopleSoft have to improve performance, expand scalability, and increase
the interoperability between its applications.
Architecture
 Physical architecture
  Tuxedo application server with EventBroker,
   Back-end Database, remote call over WAN
 Logical architecture
  – tier 1
     • PCs running the PeopleSoft client application, Tuxedo
       /WS, and Jolt
  – tier 2
     • application servers running Tuxedo services
  – tier 3
     • broad range of databases, including Informix, Oracle,
       MS-SQL server, Sybase, DB2
Physical architecture
Logical Architecture
Advice
 Keep it simple, stupid
 Clearly define your goals at project start. Make
  sure you get extensive feedback from customers
 Adopt a gradual strategy for moving to a 3-tier
  environment
 Understand what’s flowing back and forth on the
  network to make the right choices in separating
  client and server functionality
 Take advantage of third-party products. There’s
  no need to spend time developing a component if
  someone else has one that does the job
Case Study 3
 : Wells Fargo Leads the
 Way to Internet Banking

[OOPSLA 연구실]
[민 경 섭]
Table of Contents
 Background
 The Application
 3-Tier Architecture
 Advice
Background

It was once simple to understand the difference between a bank,
a brokerage house, a mutual fund company, and an insurance company.
They offered fundamental products, and there was little overlap. Today,
the differences have become blurred as financial institutions of all types
compete for investors’ funds. Leadership in the financial services industry
now requires that an organization be able to quickly adapt to a changing
market, offering new products and services to its customers in a timely
and efficient manner.
Wells Fargo Bank has become a technology leader in banking, thanks in
part to its pioneering use of distributed object computing technology. This
technology has helped the company achieve several business objectives,
including changing the way bank employees work with computers to become
customer-focused rather than account-focused
Innovations made possible through the use of this technology also enabled
Wells Fargo to become the first major bank to offer its customers secure
on-line access to account balances through the World Wide Web.
The Application : Requirements
In the 1980s, competition for investors’ funds - traditionally kept in banks -
expanded to include brokerage and insurance companies. To remain
competitive, banks began offering products such as mutual funds and
brokerage accounts - products historically outside the purview of traditional
banking. By the late 1980s, a growing trend wad compound statement
banking, where customers expected to receive a single, unified statement
listing the balances and transactions for all of their accounts - including
checking and savings, mortgage, credit card, brokerage, and retirement
accounts. Customers wanted their banking activities to be structured in terms
of their overall relationship with the bank instead of a single account.
The Application
    : Existing Systems
 Direct deposit accounts in mainframe
 Mutual funds in Digital VAX/VMS system
 Brokerage account processing in Tandem

       How can we combine all these information
       seamlessly and correctly ?
The Application
    : New System
 Customer Relationship System(CRS)
  – use BEA’s ORB, ObjectBroker
  – customers can retrieve overall relationship
    with the bank, including all accounts owned
    and their balances and statues by using SSN
    or EIN
 Applications
  –   Wells Fargo’s Internet Banking Solution
  –   Interactive Voice Response Unit(IVRU)
  –   Automated Teller Machine(ATM)
  –   A Stock market data application
Architecture
 Physical architecture
  Back-end mainframe application servers,
   Middle-tier ObjectBroker, client PCs
 Logical architecture
  – tier 1
     • windows-based client application to provide GUI
  – tier 2
     • Digital’s ObjectBroker using CORBA object model
  – tier 3
     • several legacy application systems
Interactive Voice
 Response Unit                                         Client PC
                                                      (Windows)

                                                    ObjectBroker
                      ObjectBroker

       Sun
     (SunOS)                              HP 9000
                                          (HP-UX)
                                     ObjectBroker




ObjectBroker        ObjectBroker



                                   IBM(MVS)     IBM(MVS)      IBM(MVS)
HP 9000          Digital
(HP-UX)        (VAX/VMS)
     Customer       Uses       Product




          Account

                                              Service


Deposit               Credit




     Container Account          On-line Service         Bill Pay Service




                           Business Object Model
Advice
 Transform your organization into a group that can
  effectively develop component-based,
 Include users and business participants in the
  design and development processes
 Understand the business process - both the
  existing and the desired one
 Invest time and energy in developing an object
  model that truly represents the business process
 Provide sufficient funding to maintain and
  enhance your object model
Case Study 4
 : Apple Improves Ordering
 With 3-Tier Upgrade

[OOPSLA 연구실]
[민 경 섭]
Table of Contents
 Background
 The Application
 3-Tier Architecture
 Advice
Background

Apple computer relies on its electronic ordering systems to give its
authorized resellers and service providers an easy way to order computers
and parts. This lets the resellers have greater control over the ordering
process, and it offers Apple cost savings by minimizing administrative tasks.
But when Apple decided to move to an SAP-based solution for all its
corporate functions, it found that it also had to replace the existing ordering
systems with a new one that could interoperate with SAP R/3.
To accomplish this, Apple developed a new worldwide ordering system
based on a 3-tier architecture. The new system - called AppleOrder Global -
serves as a font-end to SAP for processing electronic orders. It provides the
scalable, on-line performance needed to service thousands of resellers
around the world. AppleOrder Global is now up and running in Canada and
Europe; U.S. resellers are due to come on-line in 1998.
The Application : Requirements
To develop and roll out an electronic ordering system that would garner
internal acclaim - at least from Apple’s resellers - we need as follows.
First, to develop a scalable system with interactive interfaces.
Next, to support an international production environment. That is, we must
provide real-time performance on a global scale.
Last, to ensure that all the functionality of existing systems are offered.
The Application
 Existing system
  – five different electronic ordering systems in
    different regions around the world
 New system
  – AppleOrder Global
     • electronic ordering system
     • use SAP R/3 modules
     • users can get information about the status of
       pending orders and shipments and access their
       account and invoice information and up-to-date
       product and pricing information. etc…
Architecture
 Physical architecture
  Macintosh computers, Leased line, AppleOrder
   Global RS/6000 application server, SAP
   RS/6000 Order management server
 Logical architecture
  – tier 1
     • AppleOrder Global GUI and Tuxedo /WS
  – tier 2
     • AppleOrder Global application server
  – tier 3
     • SAP R/3 Order Management application server
                           AppleOrder Global      SAP RS/6000
                               RS/6000          Order Management
Reseller’s                 Application Server         Server
Macintosh

                     T1 Line
    Dial-up or Dedicated
    Leased-line Network
    Connection



                                           RFCs over
Reseller’s                              High-speed LAN
Macintosh


                      Physical Architecture
                                                              Tier 3
        Tier 1                   Tier 2             Order Management Server
        Client             Application Server         (acting as SAP client)
AppleOrder MacApp          Application Objects       Custom
Global GUI Framework
                         Order Management API         Order    SAP
 Application Layer API                              Management R/3
                      AppleOrder                     ABAP/4 Application
  Application Objects
                      Global API Local SAP           Routines
 Order Management API              Data
                                           API
Loca Data AppleOrder  Middleware API
   API     Global API    API                                Remote
          Middleware   Tuxedo            Remote             Function
  CTree                                                      Calls
              API     Workstation Oracle Function
Database
          Tuxedo /WS   Handler            Calls




                                    Logical architecture
Advice
 Take time in designing the system. Once you
  begin development, it’s hard to go back and
  revise the design
 Make sure you have a specialist in each
  technology
 Be sure to have people from the business side of
  the house participate as you design and develop
  the system
 If possible, reuse work you’ve already completed

								
To top