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application integration (EAI) and/or business to
business (B2B) integration to become a reality, we
need common architectures and open standards to
support it. B2B protocols attempt to establish a
common language between businesses, so that
collaborations (which occur between two business
partners) can take place without the need for pair-
wise negotiation of integration. Such protocols are
message centric by definition, describing the formal
message exchange necessary for an interaction to
take place between two business partners. B2B
protocols have been an active area of research
(Bussler, 2002) with two of the predominant
solutions in this area being RosettaNet
www.rosettanet.org and ebXML www.ebxml.org.
An alterative area of active research for enabling
automated inter-business interaction, and facilitating
system integration is obviously web service
technology (www.webservices.org). Web service
technology’s potential in the area of integration and
interoperation has generated great interest, with
initiatives from leading software vendors such as
Hewlett-Packard, IBM, Microsoft, SAP, Oracle and
Sun Microsystems. Web services are seen as a
means of integrating applications, promoting
interoperability and facilitating process management
over decentralized environments. The loose coupling
and dynamic binding characteristics of web services
are the main justifications towards achieving the
above.
The web service architecture is described by a
Web Services Stack (Kreger, 2001), however the
most appropriate stack structure remains a debated
issue, with a number of alternative architectures
offered by various consortiums and leading vendors.
Despite this disagreement, moves have been made
towards standardization, with a general consensus
existing concerning the underlying protocols
necessary in the architecture such as the Web
Services Definition Language (WSDL) Universal
Discovery Description (UDDI) and Simple Object
Access Protocol (SOAP). WSDL, UDDI and SOAP
however, are not alone enough to facilitate complex
and meaningful interactions with and between web
services, which would allow private and public
processes to harness the full potential of this
technology. Currently, many organizations are
attempting to address this problem, with proposals
intended to extend the basic web service
functionality primarily at the level which is often
referred to as the orchestration or choreography
layer of the web services stack (Uldell, 2002). These
extensions are aimed at capturing more meaningful
semantics than simply service invocations, enabling
the modelling and implementation of business
processes in the web service context. Prominent
initiatives in this area include WSCI, and
BPEL4WS. In addition, the importance of this area
is being recognized by emerging products (see e.g.
Collaxa http://www.collaxa.com/home.index.jsp).
An essential component of the next generation of
distributed architectures is message oriented
middleware (MOM). MOM provides the basic
means for target applications to communicate in a
distributed environment. Messaging middleware
however is not a new technology.
The past decade's move from client/server to
Web applications has intensified the need to move
information in real-time between disparate systems
and in a more controllable manner. In response to
these new developments, a set of Web-native
asynchronous messaging technologies has emerged
to take over where their legacy predecessors fall
short. These include products based on standard
implementations such as the Java Messaging Service
(JMS) or those that span multiple standards and
platforms.
In its new role, MOM has gained increasing
deployment and has already delivered great benefits
for communication between disparate systems, and
as a grass roots component of the web services
stack. In spite of the move from propriety networks
to open standards, the fundamental functionality of
MOM has not changed substantially. Looking at
currently available solutions, we see that the focus of
MOM has been primarily to deliver Security
(authorization, digital signatures, non-repudiation);
Reliability and Serializability (guaranteed delivery
in the proper order); and Scalability (high volume
and speed). The technology is driven by mainly two
dispatch models.
One is point to point, where message exchange
takes place between a sender and one recipient. This
is often based on queuing methods, such as the
IBM’s WebSphere MQ series (http://www-
3.ibm.com/software/ts/mqseries/). A second dispatch
model is publish-subscribe, which is used for
content dissemination to multiple recipients or
subscribers. Some essential enhancements to basic
messaging technology have been proposed, for
example in content-based routing which provides a
dynamic model, using the contents of the message to
filter messages to appropriate subscribers, see e.g.
Elvin (Arnold & Segall, 1997), Gryphon (Strom et
al, 1998), READY (Gruber et al, 1999).
3 HARMONIZED MESSAGING
Our vision of a new integration platform that would
provide universal sub-process connectivity has roots
in principles of messaging systems. The messaging
features that are imperative to the success of private
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