The Integration and Interoperability Issues of Legacy and Distributed Systems

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The Integration and Interoperability Issues of
Legacy and Distributed Systems

• Proff Dr. Mukkamala From
• CS 775
  Vijetha Devarashetty
• 
  

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Agenda

• Introduction
• Existing Issues in Legacy Systems and Distributed
  Systems
• The Syntax of Legacy Systems
• Usage of Distributed Technologies
• Summary
• Conclusions
• References

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Introduction

• Lack of interoperability
• Legacy applications represent a major investment
• Integration of the legacy environments with the
  new breed of distributed applications
• Presents an analysis of distributed systems
  concepts and design as seen from the perspective
  of the integration of a monolithic legacy systems
  into a distributed systems

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Existing Issues in Legacy Systems and
Distributed Systems

• Legacy systems communicate with other systems in
  various ways
• Systems are distributed around the world
• Designing architectures involving the integration
  of monolithic legacy systems within distributed
  systems

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• Basic Legacy Communication Architecture.

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• Move the distributed systems in the direction of
  front-ending the legacy systems in an
  integration process.
• Using legacy proprietary software commonly
  available for the legacy systems, such as GUI,
  Web enabled, ODBC enabled.

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• Therefore, this success combined with the simple
  architecture of Figure 2 can provide a one-tier
  monolithic system that has been recreated as a
  distributed system
• Robust (legacy) back office that can talk to the
  Web and talk to other parts of the distributed
  system
• The gap seems to have been bridged and the
  project is complete
• As a result , we do not have a proper distributed
  system

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• However, we will allow a simple expression of
  some distributed system requirements to guide us
  forward, which is
• The applications possibly need to be decoupled -
  they should communicate via interfaces
• Also, an important point are the interfaces to
  application components which are maintained at a
  higher level of abstraction

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• Therefore in a three-tier model the client tier
  becomes thinner.
• Focused on providing an easy to use graphical
  user interface
• Business logic moves from the client tier to the
  application server.
• At the same time, stored procedures has moved to
  the application server
• But, how is a legacy system integration process
  can be achieved?
• This question will be dealt with in two parts
  the syntax of the legacy systems, and the use of
  distributed technologies

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The Syntax of Legacy Systems

• Legacy systems are generally extremely complex
  systems.
• Therefore, a simple syntax for describing the
  legacy systems in the framework of distributed
  systems is required
• Helpful to understand the legacy systems in terms
  of what they produce and consume

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• They consume human and system input, and the
  things that the businesses collected within their
  legacy systems termed as legacy artifacts
• Public artifacts such as statements, invoices,
  interface files, dispatch advices, reports, EDI
  uploads and
• Private artifacts such as internal data files,
  internal locks, semaphores, registers, reports.
• Exposure of public artifacts to the distributed
  systems.

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Usage of Distributed Technologies

• Web services are a set of interoperable or
  connecting protocols which standardize the
  distributed systems
• Facilitate the introspection of data services,
  embed the nature of the public artifact that the
  legacy systems have to offer
• Many tools would have to be created within the
  legacy systems
• Provided by the distributed architecture within a
  Web services framework

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• The Web services works with legacy systems
  through an understanding of the legacy system's
  public artifacts and how they are integrated
  using Web services/middleware.
• Web services architecture (WSA) is an ideal
  technology to incorporate enterprise legacy
  applications into this new area

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• The eXtensible Markup Language (XML) is a central
  part of the architecture
• An XML-RPC message is an HTTP-POST request
• The body of the request is in XML, a procedure
  executes on the server and the value that it
  returns is also formatted in XML

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• Figure 4 shows the basic look and feel of the
  interface structure.
• By using this style of interface structure the
  same format of communication can be used between
  the legacy and distributed systems.

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• Application of Web services to legacy systems
  integration has the methods and protocols to
  provide a robust and common framework
• The great benefit of Web services architecture is
  that, it provides the legacy system with a close
  associate.
• Web services and legacy systems to communicate in
  the same language
• Also the distributed systems via web services
  have the power of the legacy systems within their
  architecture

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Summary

• The philosophy and rationale of a system
  integration of legacy and distributed elements
  are valid.
• Interfacing legacy systems to distributed systems
  can range from simple interface file passing
  using proprietary to Web services integration

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Conclusions

• Web services architecture may be of great value
  in this integration
• Understanding legacy systems in terms of some
  'distributed systems'-like syntax can allow the
  legacy systems to present public artifacts to the
  distributed systems via Web services
• The XML standard provides a structure for data
  presentation and process management
• The other services may also use this standard
  widely in the future
• However for both public and private legacy
  artifacts will require further development and
  analysis
• Distributed systems protocols and architecture
  must be tailored to various levels within the
  legacy systems in order for an integration
  project to succeed.

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References

• The Integration and Interoperability Issues of
  Legacy and Distributed SystemsMakki,
  S.K.Web-Age Information Management Workshops,
  2006. WAIM apos06. Seventh International
  Conference onVolume , Issue , June 2006
  Page(s)21 - 21
• Web Services No Silver Bullet, http//www.
  ecommercetimes.com/perl/story/17589.htmlstory-sta
  rt Report
• XML-RPC Specification, http//xmlrpc-c.
  sourceforge.net/xmlrpc-howto/xmlrpc-howto-spec.
  html and http//www.xmlrpc. com/spec
• Web Services - The Next Big Thing,
  http//www.internetnews.com/dev-news/article.php
  /10_970851