With the rapid acceleration in XML standardization activities and initiatives comes confusion in the industry regarding which standards should be used to implement layered solutions. As businesses race to integrate their processes with customers and suppliers, a consistent approach based on industry-accepted standards can be used minimize development and support costs across organizational boundaries. It should be possible, for example, for web services, implemented using different technologies such as COM and CORBA, to communicate in a secure and reliable fashion over the internet in a platform, language, and protocol agnostic fashion. While many areas of web service functionality are being addressed and standardized in various working groups, to achieve solution nirvana, interoperability and technology gaps in current specifications must be filled. Intel sees a number of opportunities to address industry confusion and functional gaps in specifications.
At a high level, Web service implementations can be characterized as having several layers. These layers, which can be represented in several different ways, can be classified according to features relevant to particular information constituents. One such way to diagram web service functionality that resides between organizational gateways (i.e. firewalls) follows:
|Information Constituent||Functionality Layer||Description|
|Business Decision Maker||Business Process Integration/Dictionary||Describes the steps involved in a business process using commonly accepted terminology|
|Information Technology||Packaging and Messaging||Secure, reliable packaging and data transmission in a platform, language, and protocol agnostic manner|
|Information Technology||Directories||Find a business/Web service|
|Information Technology||Communication Mediation Framework||Manage communication exchange between parties involved in a business operation.|
|Information Technology||Core XML Standards||Data representation|
|ISVs||Service-Oriented Architectures||Back-end integration|
The following sections discussion each layer in slightly more detail. While standardization of each layer may not necessarily belong in a W3C working group, working groups should be cognizant of issues associated with integration of the layers and interoperability between different specifications that may overlap functional areas. Common to each layer discussed below is the need for security and data privacy.
The Business Process Integration and Dictionary layer, owned by business decision makers, is the representation of cross-organizational business processes using mutually agreed upon, XML-based terminology. For example, a company that wishes to accept electronic invoices may implement an invoice submission Web service using RosettaNet PIPs (Partner Interface Processes), an XML description of the business process. In addition to defining the interfaces, expected behaviors can also be described that provides the interface consumer with an understanding of what to expect if the service invocation is successful or fails. The actual invoice can be described using a mutually accepted dictionary that details the fields contained in an invoice that can be processed by a back-end systems that reside behind a firewall. Challenges associated with this layer include standardization of a process and dictionary description language and framework(s). Also, in many situations such as purchasing or invoice submittal, it will be necessary to ensure that the business operation initiator is who they say they are and is authorized to perform the requested operation for their company.
IT infrastructure owners and decision makers are the primary stakeholders for this layer which should make secure and reliable packaging and transmission of business data across organizational boundaries possible in a platform, language and protocol agnostic manner. It should be possible, for example, for a Blackberry pager that is running a mini-browser or custom application that communicates via SMTP to request flight arrival or gate information from an airport web service. Since flight information is personal data, it should also be possible to protect the information from unauthorized access. In addition to dealing with handling of non-XML data and privacy issues, reliable messaging is another opportunity in this layer. Challenges associated with this layer include coordination with other specifications that address this same functionality.
IT infrastructure owners and decision makers are the primary stakeholders for this layer which provides a namespace for web service registration. Examples include UDDI and ebXML Registry/Repository activities. Ad-hoc e-Business relationships should be a long-term goal for W3C activities. Establishment of commonly agreed upon process modeling and dictionary standards in addition to providing a namespace will be necessary for success. In addition to potentially supporting multiple process/dictionary implementations, challenges in this layer include standardization of data distribution and query methods (distributed vs. centralized queries).
This layer addresses the need for session and communication coordination between parties in a business transaction. Session management and transaction coordination in a loosely-coupled environment will be necessary for multi-organizational business operations where the Web services may not be readily accessible at all times. One example might involve a business wishing to order piece parts for a customer's component assembly. In the case of high-cost, low-volume, custom assemblies, it may be impractical to keep inventory of particular components on hand, and a business may not wish to complete purchase of the components from its suppliers if the entire order cannot be filled within the requested timeframe. A communication mediation framework standard might address specification of timing and session parameters around a business transaction. IT infrastructure owners and decision makers are the primary stakeholders for this layer. Challenges and possible activities for this layer include coordination with other related standards and providing ACID-like capabilities in a loosely-coupled environment. Additionally, there will be legal challenges associated with partner agreements and maintenance thereof that will affect the directories layer as well.
This layer provides a standard way to represent data in an XML document. Examples include XML Protocol, XML Schemas, XSL/XLST, XForms, XHTML etc. IT infrastructure owners and application developers are the primary stakeholders for this layer. While there may be additional standardization activities such as W3C XML Protocol modules address key areas of functionality, other layers and functionality areas may require higher priority attention. Good progress is being made in this layer.
This layer provides the hook into enterprise systems and may have the fewest opportunities for standardization. Independent Software Vendors comprise the primary stakeholders for this layer who should be able to build competitive solutions on XML standards which may be developed in W3C and other standards bodies.
The business process, dictionary, packaging & messaging, directories and communication mediation layers of the XML-based stack described above offer many opportunities for standards activities. These standards activities will be dependent on other efforts, such as W3C XML Protocol which are already underway. It may also be necessary to liaise with other standards bodies to prevent potential fragmentation of XML standards. The reduction of the standards confusion, achieved by cooperation with other standards bodies and completion of an XML-based solution stack, will be necessary for the rapid adoption of Web services. Intel is very interested in contributing to the reduction of confusion through the establishment of a widely accepted and adopted XML-based solution stack.
Randy E Hall
e-Architecture Solutions Lab
Intel W3C AC Representative