Chapter 5- Eai Part 1

8/2/2019 Chapter 5- Eai Part 1

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ENTERPRISE APPLICATIONINTEGRATION (PART 1)

ITS580- Introduction to

Enterprise ArchitectureFramework


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CHAPTER OUTLINE

Enterprise Applications

Evolution of Enterprise ApplicationsEnterprise Application Integration

Why EAI?

What is EAITypes of EAI


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Enterprise Applications (1)

Enterprise applications are the applicationsdeveloped for large organization which will

have many, disparate subsystems.The intention for automation is tointegrate all subsystems and processes inthe systems.

Normally Enterprise Applications havedistributed architecture and huge in size.


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Enterprise applications solve businessproblems.

This involves safe storage, retrievaland manipulation of business data.It may have multiple interfaces, like:

Web interface for customersGUI application running on the desktopfor the employees.


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Enterprise Applications may communicate withremote systemsIt may have to co-ordinate data in multiple stores.It should follow a set of business rules.If any part of the system fails, the enterprise willstart losing money and if the business grows, theapplication needs to grow with it.

These factors make an enterprise application quitecomplex.


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Enterprise Application Integration, or EAI,encompasses the following areas:

Opening up ways for the information to flowfrom one application to another,

Letting applications to reach other sources ofdata outside themselves, and

Allowing other programs to peer into theinnards of formerly closed programs.

Sharing data between divisions or even betweenseparate corporations

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Examples of enterprise programs that canbenefit from EAI include

Enterprise Resource PlanningCustomer Relationship Management

Supply Chain Management

Human Resources Management

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Example


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Components of Enterprise

ApplicationAn enterprise application will have

Presentation Logic

Processing of instruction or routine

Required to display/print dataExecution of GUI

Business Logic

Perform data processing of the business

Data entry, update, query and report processingFunctional algorithm that handle information exchangebetween database and GUI

Data Access LogicData repository / Database


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Evolution of Enterprise

Applications- Single Tier

AdvantagesNo client side management is requiredData consistency is easy to achieve

DisadvantagesDifficult to maintain and reuse

Mainframe

Dumb Terminal

Dumb Terminal

Dumb Terminal

Business logic, Presentation

logic and Data access logic

reside on the single layer


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Applications- Single TierClients to Single tier EAs have only dumb terminals.Presentation logic, Business logic and Data Access logicresides at single place, mostly on mainframes. All these layersare tightly coupled to each other. Any change in them,

requires NO change at client side.So, NO client side management is required.But as, all these layers are tightly coupled to each other, anychange happening to any of the layers, will affect otherlayers as well.So difficult to maintain and reuse.

Again, for maintenance, we may require people who have skillsets in different areas such as Presentation + DevelopingBusiness Logic + Data Access logic; which is difficult to get.As data is stored at single location, integrity and consistencyof data is easy to achieve.


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Example: IBM z10 mainframe

computer

IBM z10 mainframe computer offers the computing power of 1,500 PC-style servers, uses 85 percent less

electricity, and occupies 85% less floor space. The all-new z10 is IBM's first mainframe purposely built to

handle the exploding demand for digital transactions enabled by the Internet, a trend that is creating crowded,

over-burdened corporate data centers -- computer rooms that process everything from consumer banking

transactions to drivers' license forms. (Feature Photo Service/IBM)


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Applications - Two Tier

DataBase

Data Layer

Business Logic &

Presentation Logic

Advantages

DB product independence

Disadvantages

Difficult to maintain and update


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Evolution of EnterpriseApplications - Two Tier

In Two tier EAs, the Data Layer is separated from the Businessand Presentation logic, which give app developers flexibility tomaintain database independently. Changes or migration in this layerwill be independent and can be taken care of efficiently.

But as Business and presentation logic resides together at Clientside, this applications are difficult to maintain and update.Ex: Consider the app is deployed at 50,000 clients. Any change inPresentation (frequent) or business rules (less frequent) will haveto managed/ updated at all 50,000 clients, which is difficult toachieve.And again there would be too much inter-dependence betweenPresentation and Business logic, which leads to poor maintenancecapabilities.


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Example: VB Application


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Evolution of EnterpriseApplications - Two Tier

Two tier client server architectures issuitable for the following circumstances:

when the number of users is expect to be lessthan 100

for non-real-time information processing in non-complex systems that requires minimal operator

intervention(Content from SEI websitehttp://www.sei.cmu.edu/str/descriptions/threetier.html)


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Evolution of EnterpriseApplications - Three Tier

Advantages

Business logic can change more easily - greater degree of flexibility

Increased security, as security can be defined for each service, and at eachlevel

Increased performance, as tasks are shared between servers

DisadvantagesComplexity introduced in middle-tier.

Server

DataBase

Data Layer

Presentation Logic

Business Logic


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Evolution of EnterpriseApplications - Three Tier

In 3-tier EAs, Presentation, Business and Data layers are separated andkept at different locations. This will ease maintenance of any of the layerswithout other layers getting affected.

Here, still we need to deploy the presentation logic at each and every client

separately, which will be difficult to achieve, once presentation logicchanges. (Not a scalable model)

Business logic exists at middle-tier also known as application server. Thereare various system-level issues related to the working of the middleware,such as

1.When is this server supposed to create instance of the servlet? At the startup

time or after first request comes in?2.Can it connect to database with single connection object? No. Then, if we have tocreate multiple connections, can we keep it as pool of connections? What should beits size?3.Should it support single thread model or Multi-threading is inherent?4. In that case, how many threads should be created and kept ready in a thread-pool?

So all these issues add up the complexity in the middle tier, which needs tobe answered.


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Example: ICRESS System


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Evolution of EnterpriseApplications - n Tier

AdvantagesMore loosely coupledMore reusableZero client management

DisadvantagesComplexity in the middle tier

Server Server

DataBase

Data Layer

Presentation Logic Business Logic

Thin Client


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Evolution of EnterpriseApplications - n Tier

N-tier EAs, most of the discussed issues are resolvedThe Presentation, business and data layers are separated and arelocated on separate server components.Users access the applications using thin clients. Thin clients are the

clients, which do not have any application logic residing at the localmachine. At client side, no special requirements are needed.Example of thin client : Web browser

Now, even if your web sites presentation logic is changing everyweek (this was happening for yahoo mail sometimes back) , no client

side management is required. You can change it at only one place (i.ein your server where your sites presentation logic resides)!

But as the middle-tier component exists in this architecture, soissues relating to it will still remain in this model, which can bethought as disadvantage!!!


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Example: Google Website


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Role of Application Servers inEnterprise Application

To reduce complexity in the middle tier,enterprise programmers build their applications ontop of systems called Application Servers.

Application Servers provide the system servicesto address the non-functional requirement likescalability, performance, and reduces thecomplexity of the middle tier

Resource Pooling

MultithreadingApplication developers can concentrate on thefunctional requirements by concentrating on thebusiness logic.


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DISCUSSION

Give example (s) of an applicationsystem for each of these categories:

Single Tier

Two Tier

Three Tier

N-Tier


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Enterprise ApplicationIntegration - Introduction

Enterprise application integration (EAI) enables anenterprise to integrate its existing applicationsand systems and to add new technologies and

applications to the mix.EAI also helps an enterprise to model andautomate its business processes.Enterprise application integration has always

focused on a company

s IT department integratingnew software modules or applications with itsexisting systems.


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Enterprise ApplicationIntegrationIntroduction (2)

Enterprise organizations also must weigh the costof replacing existing systems with new systemswith the cost of merging existing systems with

new systems.Discarding existing systems is never an easychoiceIn addition to retaining the existing systems,

companies can integrate them with newapplications to enhance functionality. The key withthis option is the cost of integrating the separateapplications and systems


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http://aurassystems.com/images/eai.jpg


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http://aurassystems.com/images/eai.jpg


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Why EAI?

In the past, enterprise systemarchitectures have been poorly planned.Many organizations built systems based onthe cool technology of the day withoutrealizing how these systems wouldsomehow, someday, share information .Another important factor that is driving

enterprises toward the promised land ofEAI is the broad acceptance of packagedapplications, such as Enterprise ResourcePlanning (ERP) application


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Why EAI? (2)

As organizations begin to realize the necessity ofinterconnection of disparate systems in order tomeet the needs of the business, the significance

of integration technology is being simultaneouslyfelt.Thus it becomes a very important milestone forevery enterprise to effectively architect, design,an develop systems based on EAI technology.

It needs a steep learning curve to acquire theknowledge and wisdom to identify when to applyEAI technology, selecting appropriate technology,architect a solution, and they applying itsuccessfully to the problem.


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What is EAI

EAI is the unrestricted sharing of data andbusiness processes among any connectedapplications and data sources in the

enterprise.The demand of the enterprise is to sharedata and processes without having to makesweeping changes to the applications or

data structures.Only by creating a method ofaccomplishing this integration can EAI beboth functional and cost effective.


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What is EAI (2)

EAI is the solution to the unanticipated outcomeof generations of development undertaken withoutcentral vision or strategy.

A number of stovepipe systems are in yourenterprise-for example, inventory control, salesautomation, general ledger, and human resourcesystems.

Packaged applications such as SAP, Baan, andPeopleSoft- which are natural stovepipesthemselves- have only compounded the problem.


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Types of EAI

1. Data-level EAI is the process andthe techniques and technology of

transferring data between datastores

2. Application interface level EAI

refers to the leveraging ofinterfaces exposed by custom orpackaged applications


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Types of EAI

3. Method level EAI is the sharing of thebusiness logic that may exist within the

enterprise. Applications can accessmethods on any other application

4. User interface level EAI is a moreprimitive approach. Architects and

developers are able to bundle applicationsby using their user interfaces as acommon point of integration


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DISCUSS

Concept of EAIwhat do youunderstand?

Prepare for next class

Documents

Chapter 5- Eai Part 1