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Leveraging the Power of Web Services Applications
The shift from traditional application design to Service Oriented Architecture (SOA) principles utilizing XML and Web Services promises increased IT agility and reduced technology costs. However, without effective production-caliber infrastructure, the benefits available from SOA and Web Services will go unrealized.
Many early adopters that started with a simple Web service and a corresponding consumer are now implementing composite or sequenced applications where multiple Web services are used to build an application. Others have found that the success of initial deployments have created a huge demand to address the needs of new partners and consumers of Web services. Still others have found that the myriad of identities required by disparate services create significant identity and access enforcement challenges.
As application systems are developed using SOA principals and implemented using XML and Web Services, the increasing sophistication of these applications creates added stress on the supporting infrastructure. Network traffic increases to support distributed application components; integration with Identity and Access Management Systems is required to identify and secure loosely coupled services and other principals; monitoring, auditing and control systems are needed to understand and manage dynamically changing application systems.
This white paper introduces the requirements for an XML Infrastructure that is designed to ensure the opportunities and benefits of SOA's and Web Services can be realized. For the purposes of this paper, infrastructure represents the supporting capabilities in the network that allow semiautonomous, loosely coupled elements to operate together in a meaningful fashion.
Standards and XML Infrastructure
Many architectural models and design patterns have been devised to support Service Oriented Architecture (SOA) concepts. A significant body of standards and specifications has been created to address many aspects of Web Services development and integration, and enable cross-platform, crossapplication loose coupling.
However, the standards and specifications used to define even mature architectural models are not sufficient to fully address all the issues that arise when developing an operational system. The task of addressing interoperability between various implementations is handled by several groups, such as WS-I and the Liberty Alliance. Valuable as these efforts are, the unique aspects of each Web Service deployment leaves a significant number of system issues that are not addressed.
The enormous body of standards and specifications underlying Web Services require support from an infrastructure that is designed to address the implementation, operation, integration and optimization requirements of practical and scalable deployments. These issues must be addressed before usable and operational application systems can be constructed and deployed.
This is where XML infrastructure plays a vital role. XML infrastructure is the substrate that allows complex distributed application systems to be built, tested, managed, secured, integrated, deployed, operated, validated and monitored.
Crossing Domain Boundaries
The complexity level of these new application systems increases dramatically when the various Web Service components and consumers reside in different domains. Integration of business logic from many parts of an organization may require contribution of service components from different domains including:
- Servers
- Data Centers
- Geographies
- Trust domains
- Organizational groups
The underlying policies and mechanisms that allow these boundaries to be crossed effectively must be provided as part of the execution, deployment and management environment supporting these application systems. XML Infrastructure integrates the other systems and infrastructures within an organization that facilitate crossing these boundaries.
The Essential System Problem
Applications constructed from XML and Web Service components are rapidly becoming complex systems in their own right. It is necessary to understand the operation of the system and the have the ability to control the system to ensure its optimal operation.
The Need for a New Infrastructure
A dedicated XML Infrastructure is needed for several reasons. Web Services provide a different level of abstraction from either a network infrastructure or an application infrastructure. The resulting XML Infrastructure sits between the traditional Networking and Application Infrastructures.
At the network level, the granularity of the application processing resources addressed and the need to understand complex application context are not supported by existing network capabilities.
At the application level, existing infrastructures do not support the loosely coupled, highly distributed, and extremely heterogeneous models that Web Services entail. Applications are becoming complex distributed systems that must be understood and controlled as a whole.
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