Database Reference
In-Depth Information
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The security vertical denotes the serious commitment to security in Web Services while not
complete; work is well underway to enhance SOAP and UDDI with security mechanisms;
examples include authentication and nonrepudiation.
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The management vertical denotes the absolute need for building solutions that can be
easily deployed, monitored, and upgraded. At this time, the impact on the stack layers is
unclear.
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The quality of service vertical denotes the increasing importance of guarantees regarding
response time, cost, transactional characteristics, and other aspects of e-business interactions;
work is just starting in this vertical.
Service-oriented architecture has the following characteristics:
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Distributed service-oriented architectures
: These are distributed functional elements of the
application that are deployed on multiple systems and across local and even remote networks.
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Loosely coupled interfaces
: These require a much simpler level of coordination and also allow
for more flexible configuration compared to the traditional applications that depend upon a
tight interconnections of all subsidiary elements.
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Standards
: All these connections are based upon vendor-independent standards.
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Process centric
: All services are designed with a task orientation; they function as discrete
steps in a larger workflow or business process.
10.3.1 Web Services
Web Services emerged from the initial efforts to achieve integration and interoperability between
distributed software applications. The last decade was dominated by the client/server-and-database
approach to systems, an innovation that was pioneered by SAP for enterprise applications with the
introduction of SAP R/3 in 1993. Client/server applications are designed with a dedicated client
and server, each server used by a single application and with integration performed by expen-
sive point-to-point data connections that quite often use proprietary communication protocols.
Because of the huge number of required interfacing connections, this resulted in large escalations
in costs for the development and maintenance of applications. As mentioned earlier, this approach
to application integration resulted in integration costs that were reported to be between 30%
and 60% of the total IT budget of companies. EAI solutions thus led to a very dense network
of applications and interfaces, which were difficult to maintain and that too at very high costs.
As an intermediate solution, to obviate the need for developing customer-specific interfaces, the
communication between applications was abstracted by using XML messages to enable different
applications to interact by using a standardized format. However, this still leaves unaddressed the
fundamental issue of integrating the business processes themselves.
Web Services are the interface technology of the future. They are the new standards for cre-
ating and delivering cooperative applications over the Internet. Web Services allow applications
to communicate irrespective of the platform or the operating system. By using Web Services,
developers can eliminate major porting and quality testing efforts, potentially saving millions of
dollars. They will radically change the way that applications are built and deployed in the future.
As explained in Section 10.1.3 “Enterprise Component Architecture,” a developer can create
an application out of reusable components. But what good is it to have a large library of reusable
components if nobody can find out that they exist, where they are located, and how to link to and
communicate with such programmatic components? Web Services are standards for finding and
