This document discusses enterprise application integration (EAI). It defines EAI as the unrestricted sharing of data and business processes among any connected applications and data sources in the enterprise. The document outlines EAI architectures including 1 layer, 2 layer, 3 layer and multi-tier architectures. It describes middleware and how it allows communication across different platforms. Benefits of EAI include lower development costs, integration and opportunity costs as well as lower maintenance efforts.

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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