The greatest benefit of XML lies in its potential for managing "islands of data" locked into proprietary tools, systems, applications, and technologies through the use of a common data format that's understandable to any process and system that use it for data representation, data exchange, and application integration. In fact, if XML doesn't achieve this potential, there is little point in using it at all.
Following a trend all too familiar to the IT industry, XML is being seen as a silver bullet that will magically solve all the problems of data integrity, instantly remove islands of data, and disentangle the spaghetti of data interfaces across the enterprise. Typically, those who have willingly embraced this "Next Big Thing" approach will be sadly disappointed, and another real opportunity to move forward could be lost.
XML's greatest strength is also its biggest weakness. It is so flexible that different vocabularies and structures can be written to define the same type of data. Left unchecked, this can lead to a confused set of fragmented, point-to-point XML formats that simply move the problems of data islands and integration around, instead of actually addressing them. Evidence from early (and very expensive) XML implementations confirms this problem. Many software vendors are implementing proprietary layers of XML that can give the appearance of providing a common format for data exchange, but in fact are designed to lock users into proprietary platforms. As a result, eXtensible Markup Language is fast becoming the "eXtensively Misused Language."
XML will only succeed when businesses truly embrace the principles of openness, transparency, and reusability that XML can support. This will require moving away from point-to-point negotiations for exchanging data toward an agreement on standard ways of defining and expressing XML vocabularies, and on common guidelines for the implementation and ongoing use of these standards.
The Need for an XML Clearinghouse
The effective application of XML to overcome the "islands of data" problem requires proper implementation strategies to ensure consistent exchange and reuse of information assets using XML. All projects using XML should have uniform access to appropriate XML documents and their related metadata, which can be only be achieved through the development and deployment of an XML Clearinghouse (also known as XML registry and repository) for the enterprise that provides a single location to store and manage the common XML standards and vocabularies used in the enterprise.
An enterprise XML Clearinghouse allows users to:
1. Discover and use pertinent XML components in the enterprise
2. Register additional XML components that can be reused (e.g., projects, applications) by other projects within the enterprise
What is an XML Clearinghouse?
An XML Clearinghouse is a software model that consists of two key components:
1. Registry: Stores relevant descriptive information, or metadata, about registered information components and their associated objects, and allows the metadata to be operated on in various ways.
2. Repository: Stores the registered information components and their associates. It also provides interfaces to retrieve and use registered information components and associated objects.
Registered information components and their associated objects provide users with the information necessary to effectively use them. The key information components registered in the Clearinghouse are the XML Schemas and XML DTDs that can be reused within the enterprise by XML developers, projects, applications, etc. Other information components may also be registered.
Examples of associated objects of registered information components include:
- XML documents
- XML specifications
- XML specifications usage
- UML models
- Other projects that use the information components and the implementation details
- XML design and implementation guidelines
- Usage conflicts and collisions, including details of their resolution
- Business process descriptions
- Trading partner agreements
The relationship between an XML registry and an XML repository is shown in Figure 1.
The XML Clearinghouse can store different XML-specific files: XML, XSL, XSLT, XSD, and many others from the XML family. The main goal of the registry and repository is to share XML vocabularies between interested parties so they can discover and understand each other's vocabulary. The XML Clearinghouse ensures consistency, quality, and compatibility among XML projects within the enterprise and also helps to ensure that the XML standards used are controlled and monitored effectively.
Using the XML Clearinghouse
The following step by step example illustrates how the XML Clearinghouse works:
Project A of an enterprise develops an XML vocabulary (DTD or Schema) for structuring the customer name and address data that it uses.
Project A registers the vocabulary (information component) with other appropriate and relevant information (associated objects) as needed, such as description of the vocabulary, implementation guidelines, and so on, with the registry of its enterprise's XML Clearinghouse.
Project A wants to communicate with Project B by submitting name and address data electronically as XML documents that are validated against the registered XML vocabulary. Instead of writing its own XML vocabulary for name and address data, Project B should seek to use an XML vocabulary that has already been registered with the XML Clearinghouse of its enterprise for structuring their submission, as per the policy implemented by the enterprise.
Project B then searches the registry of the XML Clearinghouse for vocabularies that are designed for name and address data, to see how they have been used by other projects, and in particular to verify what has been adopted by Project A, and selects and downloads the proper vocabulary.
Note that the registry should also provide facilities to store multiple versions of the same XML vocabulary. However, it is up to each project to decide which versions of the XML vocabulary it will support.
Figure 2 shows how an XML developer can hypothetically use an XML Clearinghouse in a government environment consisting of many agencies and business units.
Benefits of an XML Clearinghouse
The XML Clearinghouse is an essential part of the infrastructure that supports the reuse of common information components across business applications. It has four main benefits:
1. Helps protect enterprise information assets: The information assets represented in the form of XML Schemas and DTDs that are commonly and consistently used across the enterprise are preserved, maintained, and protected from being locked into proprietary or custom-built applications that result in new data islands.
2. Promotes cross-project activities: The XML Clearinghouse stores information on the use of the XML Schemas and DTDs by different projects, which gives projects insight into XML-related activities and provides opportunities for collaboration.
3. Promotes a common understanding of information components: Storing the information models and metadata for subject areas (such as customer, product, etc.) as XML Schema in a single location promotes a common understanding of the purpose of the registered information components.
4. Facilitates B2B communication: External business partners can access the XML Clearinghouse so they can exchange data with the enterprise in the same standard ways used by internal business systems. This can expedite B2B communication and greatly reduces the cost of supporting it.
The main thrust of the XML Standards Clearinghouse work is to provide visibility and awareness of XML data elements in use within various functional areas across an enterprise. This awareness is important to application integrators and system interfaces.
Use of an XML Clearinghouse needs governance
Despite the benefits of having an XML Clearinghouse for an enterprise, if the XML Clearinghouse were left uncontrolled, every point-to-point XML vocabulary would be registered, each reflecting the narrow interests of application areas. This would result in the proliferation of many diverse data formats within an enterprise to represent the same piece of data. New data islands of information would be created, resulting in new and expensive one-off formatting problems. This would seriously threaten the credibility and integrity of the XML Clearinghouse and defeat the purpose of using XML in the first place.
An XML Clearinghouse will only be effective if policies are set, usage guidelines established, and a management and funding process put in place for effective operation. Policies and procedures should include:
Registration procedures for new XML components
Verification procedures for input to the registry
The extent to which developers will be required to consult the standards registry when deploying XML data structures
Classes of compliance for categorizing how rigorously projects within the enterprise adhere to standard data structures and definitions
A configuration management process to keep track of successive versions of each registered component
Benefits of a governance model
The benefits of a governance model to manage XML Clearinghouse use in an enterprise are numerous. Some of the key benefits are listed below:
Facilitates the convergence of standards within an enterprise, and reduces the costly divergence and fragmentation of XML used by different business units/projects.
Supports the management and control of the information assets of an enterprise by ensuring consistency, quality, and compatibility of the information assets used across the enterprise.
Enables an enterprise to track and monitor the progress of different XML projects, thereby avoiding duplication, conflicts, and inconsistency in the XML initiatives.
Provides a set of guidelines, policies, and procedures for implementing XML standards in an enterprise. This will provide a common understanding of data and a standard way of implementing XML that will enable the interoperability of information and business processes.
Enables an enterprise to monitor the evolution of the XML standards at national and international levels.
Resolves conflicts between different projects within the enterprise regarding the definition, creation, usage, and implementation of XML standards.
Potential XML-Related Work in an Enterprise and the Importance of Governance
This section describes the different types of XML-related work experienced implementing XML strategies for enterprises and the importance of governance for such projects.
Projects that use existing XML standards
Projects could be using existing industry XML standards. It's therefore important for the enterprise to monitor and govern this type of project for the following reasons:
Several projects in an enterprise could be planning to use the same XML standard, which could result in duplication of effort in evaluation and implementation.
A single mechanism should monitor the changes in industry standards on behalf of the enterprise and document how to apply any changes within applications.
It's important to have a common agreement on which XML standards will be adopted, since there could be many flavors of similar standards.
It's important to have a common agreement on how XML standards are implemented since an XML standard could be implemented in different ways and still meet its purpose.
Projects that need to extend or develop XML standards
There will be situations where existing industry XML standards don't meet the requirements of a project. In such circumstances the project may decide to cover identified gaps by extending existing standards, or by developing a new standard. It's important for an enterprise to monitor and govern this activity in order to:
Produce a common set of guidelines for adopting, changing, or building XML standards. This will encourage interoperability and foster a common understanding and use of the standards in an enterprise.
Ensure that effort is not duplicated where two projects share the same requirements.
Encourage projects with similar requirements to collaborate to extend or build common standards that meet all requirements, thereby producing more robust XML standards and fostering interoperability and common understanding.
Minimize the impacts that changes to existing enterprise XML standards might have on projects and business applications.
Developing enterprise XML standards
Projects in an enterprise may be building an enterprise XML standard for a subject area not addressed by existing standards, and the enterprise must govern this type of activity. It's important to:
Gather all inputs and requirements in a central place in order to expedite consensus across business units about the development and deployment of XML standards
Enable different projects to communicate using a common language when developing or adopting XML standards
Coordinate the enterprise XML standards initiative to avoid version control problems, conflicts and collisions, confusion, and misunderstandings about developing and deploying XML standards
Turn locally developed XML into open industry standards
There may be times when an enterprise decides to submit an XML standard it has developed to a global XML standards body or a local (e.g., national) standards body to ratify it as an "open" XML standard. For example, our organization submitted three XML standards for customer information management to OASIS to develop and promote them as open industry standards free of royalty and IP issues:
- NAML: Name and Address Markup Language
- CIML: Customer Identity Markup Language
- CRML: Customer Relationships Markup Language
This has resulted in five open industry standards under the control of the OASIS Customer Information Quality Technical Committee:
- xNL: Extensible Name Language
- xAL: Extensible Address Language
- xNAL: Extensible Name and Address Language
- xCIL: Extensible Customer Information Language
- xCRL: Extensible Customer Relationships Language
It's important for an enterprise to monitor and govern this type of activity in order to:
Ensure that the enterprise's interests are strongly and accurately represented at the global or local XML standards level when modifications and extensions to the standards are being considered
Position the enterprise as a world leader in the development of global XML standards for industry (this requires active sponsorship by the enterprise)
Ensure that changes and extensions ratified by the global or local XML standards body to standards submitted by the enterprise are reflected in their deployment within the enterprise
The XML Standards Governance model will enable enterprises to form closer relationships with global/local standards bodies and provides the opportunity to establish business relationships with other organizations involved in the standards initiative and those who are using the standards.
Conclusion
XML allows the specification of an arbitrary set of nonbinary tags for representing information components. This offers an open, independent, and low-cost platform for representing information for a multitude of purposes. However, left uncontrolled, the introduction of XML results in the proliferation of many diverse data formats that represent the same piece of information. This would create new islands of information and result in a new version of the expensive one-off formatting problems that most enterprises are looking to solve.
Information components can be shared, exchanged, and reused through the deployment of an XML Clearinghouse for the enterprise that provides a single, common, sharable location to store and manage the XML standards and vocabularies used in the enterprise. However, the technical solutions used to implement an effective XML strategy need to be managed properly. It is therefore important for an enterprise to establish an XML Standards Governance Model for the XML Clearinghouse to oversee the effective development and deployment of an integrated set of XML standards to represent, share, and exchange enterprise information components.
References
Ferguson, R. (2002). "XML: Plugging into 'standard' hybrids." eWEEK. January.
Kumar, R. (2002). "XML Standards for Global Customer Information Management." DM Review. Volume 12, Number 5.
ebXML: www.ebxml.org
Challenges of effective adoption of the Extensible Markup Language. (2002). GAO Report to the U.S. Government. April.
OASIS Customer Information Quality Technical Committee: www.oasis-open.org/committees/ciq
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