SOA Definition

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SOA Definition

• The goal of an SOA is to allow business
  activities to be orchestrated as components in
  applications targeting both internal and
  extra-organizational actors, ultimately enhancing
  business agility

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SOA in Action
Chapter 10 Enterprise SOA

• Padmaja Mandava
• Harish Kethireddy

CSU Prof David Woolbright
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SOA In Action
This chapter shows how a service can be
implemented in the real world to serve the need
of different usage models.

• Building Web Applications
• Enterprise Application Integration
• Business -to- Business
• Fat Clients
• Small devices and
• Multi Channel Services

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Building Web Applications

• Web applications are particularly suited as
  clients for a Service Oriented Architecture Due
  to

• Web requests are stateless by nature
• Provide rich interfaces with high degree of
  interactivity.

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Building Web Applications Contd...

• Initial authentication by web tier either by
  username and password or by a certificate.
• Subsequent call authentication is done by

• Principal Propagation
• Trust

State of service is stored in web tier
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Building Web Applications Contd...

• Precautions should be taken in handling service
  requests by trust and when handling duplicate
  requests by impatient user.

Main Disadvantage In principal propagation, for
web application that uses a framework that
doesnt support this feature, the process of
authenticating for subsequent calls is not
straight forward.
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Enterprise Application Integration

• EAIs pose a certain set of requirements in
  addition to profound non-technical issues that
  must consider.

• Highly fragmented application infrastructure
• Use of multiple programming platforms and
  communication infrastructures from multiple
  vendors.

Nevertheless, if an SOA is properly deployed, it
will address many technical and core concerns
related to EAI.
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Enterprise Application Integration Contd
Quality Customer Service
Strategic Insight
Flexible Business Model
Rapid Market Response
Innovative Products Services
Low Cost
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Enterprise Application Integration Contd

• Service Enablement

• Encapsulate the functionality of an existing
  application
• Define a service façade that sit between
  application frontend and the distributed
  components.

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Enterprise Application Integration Contd

• Upgradeability

The service provider must be able to upgrade a
service without having an impact on current
applications that integrate these services. Two
main styles doing this are

• Backward Compatibility
• Provision for different versions.

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Integration vs. Interoperability

• Integration
• Two (or more) applications exchange data Ex EAI
• Interoperability
• Two (or more) applications are able to exchange
  information (if they want to). Ex B2B imp

• If ( _youHaveQuestions )
• throw FatalException( Service Not Available any
  more )
• Else
• ? ? ? ?
• PadmajaPlease take over.

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Business-to-Business

• A corporate offers some service to another
  corporation over public networks such as the
  internet.
• In B2B scenario, both the service consumer and
  the provider benefit greatly by following two
  policies

• Following global standard protocols while
  developing the services. and
• Providing location transparency by registry
  services.

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Business-to-Business Contd...

• In B2B services, in most of the scenarios,
  Authentication is achieved by trusting the remote
  system believing that business partner is
  trustworthy.

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Fat Clients

• An application type that provides a lot of its
  processes on the client machine and usually
  relies on a single backend system, which can be a
  relational database, is commonly synonymies as
  Fat Clients.

• Disadvantage
• Complex deployments

• Advantage
• Known for most users friendly, stability and
  interactivity.

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Fat Clients Contd...

• With SOA implementation, fat clients can be
  converted as rich clients.
• The core advantage of this method is that the
  rich client application can be completely
  decoupled from the backend implementation.

Fat clients authentication is by trusted clients
or might be authenticated using a certificate.
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Designing for small Devices

• Services are developed for specific device due to
  
• Compatibility of technology,
• Limited processing power,
• Limited memory availability and
• Limited data entry support.

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Designing for small Devices Contd...

• Security and authentication is often a big
  challenge due to limitations.
• Processing power and available memory may not
  allow encryption and signature of messages.
• Authentication can be done in mainly two ways.
• One by username and password entering directly
  and second by
• certificate stored in client (device)

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Designing for small Devices Contd...

• Use resources for the application rather than the
  communication.

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Multi-Channel Applications

• SOAs are extremely effective at implementing
  multi-channel applications.
• Accessed through different channels by either
  human users or programs.
• Typical multi-Channel applications can provide
  channels such as the
• Internet,
• various mobile channels such as WAP,
• B2B,
• fat clients..

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In Conclusion

• we have the following challenges in developing
  SOA applications
• Handling duplicate requests.
• Handling transaction based operation services.
• Location transparency. mainly in B2B applications

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In Conclusion Contd...

• Using simplest protocol in small device
  applications
• And finally, Granularity of the service, security
  constraints, and the technologies to use is
  mainly depending on usage scenario of the service.

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Summary

• SOA Design is NOT an IT-only initiative
• SOA Design ! distributed computing
• As always no single or definitive answers but
  rather guidance, best practices and patterns
• Nothing replaces hands on experience

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Thank You
CSU Prof David Woolbright
SOA in Action Chapter 10 ESOA
Harish Kethireddy
Padmaja Mandava