An Introduction

1. Enterprise Application Integration
(EAI)
System Integration & Architecture
Inam Ul Haq
BSIT-6th
University of Education Okara
Lecture 3

2. Contents
• EAI?
• Architectures
• Middleware
• What is EAI
• A Typical EAI System
• EAI Benefits
• Conclusion
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3. Defining EAI
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• Why EAI?
– Wouldn’t it be great if everyone used the same servers with
the same operating system with the same clients.
• Reality is very diverse. We can expect a mix of mainframes,
Windows, UNIX, Linux, VMS, as well as many other systems
– Getting them to work/share data together is the issue!
– EAI is defined as “the unrestricted sharing of data and
business processes among any connected applications and
data sources in the enterprise.”
• Using EAI effectively will allow us to integrate without making
major changes to our current infrastructure.
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4. Architectures
• 1 layer architecture
• monolithic Information Systems
• presentation, application logic, and resource
management were merged into a single tier
• 2 layer architecture
• separation of presentation layer from other 2 layers
(app + resource)
• became popular as 'server/client' systems
• 3 layer architecture
• can be achieved by separating RM (resource
management) from application logic layer 4/31
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5. 5/31
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6. Multi-tier Architectures
In software engineering, multitier architecture (often referred to as n-
tier architecture) is a client–server architecture in which presentation,
application processing, and data management functions are physically
separated.
The most widespread use of multitier architecture is the three-tier
architecture. (Wikipedia)
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7. Multi-tier Architectures
• Where to put the business-logic?
• Middle tier -> YES!
• Business logic has its own tier
• A data-tier application (DAC) is a logical database management
entity that defines all of the SQL Server objects - like tables, views,
and instance objects
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Web browsers
HTML, Java
GUI clients
C++, VB, Java
Client tier
user interfaces
Middleware
Server
e.g. Web server
Middle tier
business logic
Data tier
data sources
Databases
Legacy Systems
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8. Middleware I
• Allows communication
• through a standard language e.g. JSP
• across different platforms
• between legacy and moderm applications
• Takes care of
• transactions between servers
• data conversion
• authentication
• communications between computers
• E.g. Web servers, application servers, CMS, and releted tools
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9. Middleware III
• Main use today: covering thin client architectures (heavily
server dependent)
• CORBA enables communication between software written in different
languages and running on different computers.
• EJB (Enterprise JavaBeans) is a subset of the Java EE specification.
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User interfaces
Business logic
Data sources
Client-tier (GUI applications, browsers)
Middle-tier (CORBA/EJB)
Data-tier (databases, mainframes)
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10. What is EAI
• Integrates applications and enterprise data sources so that
they can easily share business processes and data
• Integration is done without significant changes of applications
and data sources
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11. 11/31
Middleware
Middleware
Middleware
Middleware
Middleware
EAI
Middleware
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12. 12/31
ERP System
Legacy System
Databases
CRM System
Enterprise Portal
Application
Financial System
Suppy Chain Mgt System
Internal Applications
(Java,C,C++)
EAI
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13. EAI benefits:
• Lower development costs
• Integration is simpler because systems are more
loosely coupled than in object brokers
• Lower opportunity costs
• Integration is done more quickly
• corresponding cost savings reachieved sooner
• Lower maintenance effort
• adapters extract the interaction with external systems
• significant advantage from the software engineering
point of view 13/31
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14. Real World Example:
• 1875 Alexander Graham Bell invented the telephone
in the 19th century and AT&T became parent
company of the Bell System, the American telephone
monopoly
• The system broke up into eight companies in 1984.
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15. Conclusion
• Enterprises integrate their applications
• less expensive than replacement
• more efficient than „information islands“
• Enterprises must establish web-presence and make business
services available to web-clients
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16. References
• http://www.ibm.com
• http://www.att.com
• http://www.eaipatterns.com/
• http://www.iwaysoftware.com/
• http://www.capterra.com/enterprise-application-integration-software
• http://www.infoworld.com/techindex/enterprise_application_integration_-
_eai.html
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