 | |||
|
Wednesday May 22 2002 Web Services and Virtual Enterprises Virtual Building Blocks Download the free extended PDF version of this article. The notion of "virtual enterprises" has been around for quite some time and in some ways most IT efforts are concentrated on realizing some of the features of virtual enterprises, even without recognizing or labeling them as such. The meaning of the term "virtual enterprise" itself has undergone several versions or modifications. Some synonyms include "virtual corporation", "virtual organization", and, more recently, "extended enterprises". In this article, we'll take a look at how Web Services can help us to create a virtual enterprise. What do we mean by Virtual There are many connotations associated with virtual organizations. Virtuality has several dimensions, which are not orthogonal. VoNet (http://www.virtual-organization.net/) provides a good source of articles and discussions on virtuality. For our purposes, we will confine discussion to the following points:
Almost Real With information technologies a virtual organization will behave almost like a real organization for the external actor or consumer. Virtual Worlds Concepts such as Virtual Exhibitions, Virtual Shopping Malls, or Virtual Schools capture this dimension of virtuality. These worlds do not physically exist. They are created and accessed typically through Web browsers. Virtual Presence Virtual presence means the person is available, participating, and conducting their tasks without physically being there. Virtual offices are perhaps the most common example. Virtually Cohesive and Well Aggregated The key feature of virtuality here is that the various applications, repositories, and even roles or organizations appear to be well aggregated and integrated. Virtual Existence This means the organization can come together whenever needed. A good example of this is a network of consultants who can come together whenever there is a need. Dynamic and Temporal One of the big advantages of a virtual organization is the fact that it is dynamic; partners could change. With virtual enterprises the focus is on the objectives - what the organization is trying to achieve. The Scope of Virtual Enterprises Virtual enterprise does not necessarily imply connectivity to other external organizations, although the ultimate goal and model of virtual enterprises will most likely involve many trading partners in value/supply chains. Even efforts such as the Semantic Web and Ontologies are attempts to achieve virtual enterprise characteristics when it comes to connecting concepts and content on the Web. Virtual enterprises features, concepts, and technologies span internal applications, acquired organizations, and of course trading partners. The scope of virtual enterprises can be summarized as follows:
Foundational Features of Virtual Enterprises The following are the foundational features of virtual enterprises:
Web Services for Virtual Enterprises So what does all this have to do with Web Services? Just about everything. The following diagram illustrates the Web Services technology stack:
The Web Services lower stacks (SOAP+WSDL+UDDI) actually define Web Services. . XPDL and Wf-XML are from the Workflow Management Coalition (WfMC). XPDL stands for XML Process Definition Language and, as its name suggests, it is used to define processes. BPQL (Business Process Query Language, http://www.bpmi.org/bpql.esp), from BMPI, and Wf-XML can be used to query the states and control the execution of process instances. Virtual Enterprises are realized through process integration. The processes involve human participants, packaged applications, custom applications, and trading partners. There are some inherent advantages that make Web Services the ideal platform for realizing virtual enterprises, which include ease of integration, the ubiquity of XML and HTTP, and the ease with which business partners may be discovered. Ease of Integration As we have seen elsewhere, integration is difficult, and many complex integration projects have failed. That is about to change with Web Services. With Web Services integration is seamless. The technologies that Web Services use - such as HTTP and SOAP/XML at the wire level and XML standards for registries and payload - are robust and readily available. There is tremendous flexibility in binding the implementation of a published interface (WSDL) to the actual run-time execution of the Web Service. As long as the operations defined in the port types and the overall protocol through SOAP messages is followed, the service provider has complete flexibility in implementing the Web Service. SOAP/XML over HTTP There are two fundamental advantages here for XML in Web Services:
Discovery of Business Partners The Web Services architecture is dynamic. Service requestors dynamically query internal (private UDDI) or external (public UDDI) registries and discover potential business partners and the services they support. If several service providers have implemented the same service, the service requestor can dynamically bind to a particular service provider, thus realizing one of the most promising features of dynamic e-businesses. Outstanding Issues It should be pointed out that even though a number of key technologies and standards for Web Services have been defined (such as SOAP and UDDI), there are still several issues that need to be addressed before the full potential of virtual enterprises through Business Process Management over Web Services architectures can be realized. Two of the most important technologies that are particularly important in B2Bi are reliability and security. A number of standardization efforts are addressing these. A companion article in Web Services Architect (http://www.webservicesarchitect.com/content/articles/fernandez01.asp) describes some of the security standard associated with Web Services, including Security Assertion Markup Language (SAML, http://www.saml.org/) and XML Key Management Specification (XKMS, http://www.w3.org/TR/xkms/). The Web Services End Point Language (WSEL, http://www.w3.org/2001/04/wsws-proceedings/rod_smith/img13.htm) addresses the complex issues of Quality of Service and Service Level Agreements between business organizations. A number of Web Services vendors such as Flamenco Networks (http://www.flamenconetworks.com/) and Grand Central Communications (http://www.grandcentral.com/) are addressing these important security and reliability issues through Web Services Networks. For more on Business Process Management (BPM), see http://www.webservicesarchitect.com/content/articles/oriordan01.asp. Web Services For Virtual Enterprise Requests Web Services represent a distinct advantage in several areas for the virtual enterprise. Organizational Model The UDDI registries in Web Services architectures already support Yellow and White pages for businesses. These could and should be extended to provide more comprehensive information about organizations, to enable the creation of partners or participants in virtual organizations. Vocabularies The XML message or document payload represents the input and output data of particular exchange or activity. Each vertical domain will have several XML schemata for its message definitions. Different types of applications (ERP, CRM, HR, legacy applications) will have their own data types and operations. Process Definition A business process is actually the best way to compose Web Services. Thus, different Web Services can be brought together through process integration and offered as new Web Services. A number of the proposed standards for process definitions such as BPML from BPMI.org and XLANG from Microsoft have solid theoretical foundations. Process Actions The composition of Web Services through processes allows the specification of the process templates. Business process management spans and includes workflow, enterprise application integration, and business-to-business integration. Each of these categories or processes will have different requirements for the process actions mentioned here. Nevertheless, it is important for a business process infrastructure potentially executed and supported by many process engines to support the process actions mentioned here (and many more) as Web Services. Web Services can be used to accomplish the following things:
Process Status Communication The BPQL (Business Process Query Language) standard from BPMI as well as Wf-XML from WfMC both address the dynamic communication of the status of processes. This is especially important for longer-duration processes. For instance, if an organization activates a large and complex process that consists of Web Services from different partner organizations, decision makers might be interested in finding out how far the process has progressed in its choreography of Web Services activities. If human participants are involved, processes tend to be longer. Consider for instance the process of writing and publishing a business plan. It can take several weeks. Many sub-processes involving human and system participants, such as Document Management and Accounting Systems, could be involved. An executive stakeholder might be interested in the status of the business plan process. The status could also be used by automated systems to enact business rules that implement the Service Level Agreements (SLAs) between organizations. There is a lot of value in Web Services that query the status of one or a collection of process instance states. For instance, a Web Service could provide information on which shipping company made the most on-time shipping in the past three months, through gathering the status information of shipping processes. Thus the business intelligence gathered from the status of process instances could be used to dynamically bind the service provider (participant). Conclusion The challenges in realizing virtuality are many. Despite the challenges of process re-engineering and the difficulties of integration efforts, however, the notion of a virtual enterprise has persisted. In fact, most enterprise application integration, business-to-business integration, and workflow projects have addressed virtual enterprise issues, even if they are not labeled as such. All supply and value chain projects attempt to implement virtual enterprises. Web Services through their robust ease of integration, flexibility, and support of XML vocabularies provide the best platform to realize virtual enterprises. Every application and computer-human interaction can be modeled as a Web Service. Every domain is being enriched by agreed upon XML vocabularies for particular vertical or horizontal applications. XML transformation and other associated technologies facilitate the system level integration of services and trading partners. Finally, the recent advances in business process management standards for Web Services have made it possible for organizations to define, deploy, and interact with Web Services within the context of processes spanning the entire virtual enterprise. There are of course challenges: Web Services can be "bulky" or slow; some of the technologies associated with Web Services are still immature. This is especially true of security, reliability, metering of Web services, and message tracking. There are, however, aggressive and serious efforts that are addressing security, reliability, process flow standards, and much more. Perhaps most importantly, those who are raising flags and doubting Web Services are not offering any serious alternative that could challenge and provide a solution on a par with XML over HTTP. In other words, Web Services provide the best framework to realize virtual enterprises. The extended PDF version of this article is available now. Web
Services and Virtual Enterprises by Setrag Khoshafian Adobe Acrobat format (PDF) - 133K If you are interested in obtaining additional information on Web Financial Services capabilities and the value they can bring to your Enterprise, contact Nick Berberi, VP Business Development at nberberi@wfsc.com. Keep up to date with all the new articles and features on
Web Services Architect: |
