1. INTRODUCTION
Nowadays, many organizations form dynamic partnerships
to effectively deal with market requirements. Companies
focus on their core business and outsource secondary activi-
ties to other organizations. Growing complexity of products
requires co-makership relations between organizations. Val-
ue chains require a tight cooperation between companies
participating in these chains. As a result, the creation of vir-
tual organizations has become a major issue. To enable their
operation, the information processing infrastructures of the
participating organizations need to be linked. In the context
of the close cooperation between companies, automated sup-
port for processes crossing organizational boundaries is an
essential element [27]. The advent of business-to-business
electronic commerce adds a dynamic dimension to this: vir-
tual enterprises are formed and dismantled dynamically in
rapidly evolving markets. Consequently, their process sup-
port infrastructure must be constructed dynamically. Work-
flow management systems that control the processes in the
individual organizations are a key element here.
In today’s businesses, the application of workflow man-
agement systems (WFMSs) for automated process support is
widespread. The use of WFMSs ensures a well-structured
and standardized management of processes within organiza-
tions [12]. Traditionally, the emphasis of workflow manage-
ment has been on homogeneous environments within the
boundary of a single organization. Using workflow support
in virtual organizations, however, implies extending the
functionality of workflow support such that workflow man-
agement systems in different organizations can be linked to
manage integrated cross-organizational processes. The
extended workflow support must be able to deal effectively
with heterogeneous workflow environments, well-specified
levels of autonomy of partners in a virtual enterprise, and
dynamic formation of new and dismantling of existing col-
laborations. Linked workflow systems should allow one
organization (the service consumer) to start a process (a ser-
vice) on its behalf in another organization (the service
vol 15 no 5 september 2000 277
Comput Syst Sci & Eng (2000) 5: 277–290
© 2000 CRL Publishing Ltd
CrossFlow: cross-organizational
workflow management in dynamic
virtual enterprises*
Paul Grefen*, Karl Aberer†, Yigal Hoffner‡ and Heiko Ludwig‡
*Computer Science Department, University of Twente, PO Box 217, 7500 AE Enschede, Netherlands. Email: grefen@cs.utwente.nl
†GMD-IPSI, Dolivostrasse 15, D64293, Darmstadt, Germany. Email: aberer@darmstadt.gmd.de
‡IBM Research, Säumerstrasse 4, CH8803, Zürich, Switzerland. Email: {yho,hlu}@zurich.ibm.com
This paper gives a detailed overview of the approach to cross-organizational workflow management developed in the CrossFlow project. CrossFlow is a
European research project aiming at the support of cross-organizational workflows in dynamic virtual enterprises. The cooperation in these virtual enterprises
is based on dynamic service outsourcing specified in electronic contracts. Service enactment is performed by dynamically linking the workflow management
infrastructures of the involved organizations. Extended service enactment support is provided in the form of cross-organizational transaction management
and process control, advanced quality of service monitoring, and support for high-level flexibility in service enactment. CrossFlow technology is realized on
top of a commercial workflow management platform and applied in two real-world scenarios in the contexts of a logistics and an insurance company.
International Journal of
Computer Systems
Science & Engineering
*The work presented in this paper is supported by the European Commis-
sion as ESPRIT project No. 28635

provider) and receive the results of this process. As black-
box processes are too coarse for tightly cooperating organi-
zations, advanced monitoring and control mechanisms are
required to support fine-grained interaction between these
organizations, while preserving their autonomy as much as
possible.
This paper gives a detailed overview of the conceptual
and technical approach in the CrossFlow project, which aims
at developing support for cross-organizational workflow
management in dynamic virtual enterprises using an out-
sourcing paradigm. CrossFlow aims at an end-to-end solu-
tion, including all functionality from contract establishment
for outsourcing services to workflow enactment for execut-
ing services. It is this end-to-end overall view that we pre-
sent in this paper. Details of specific CrossFlow aspects are
described in other publications [21, 25, 41, 24].
CrossFlow is a European research project of the 4th
ESPRIT Framework that researches and develops cross-
organizational workflow support for virtual enterprises. The
prime contractor in CrossFlow is IBM, participating with its
e-business group of the Zürich Research Laboratory in
Switzerland, its development laboratory in La Gaude,
France, and its workflow software development group at its
site in Böblingen, Germany. Technology providers in the
consortium are GMD-IPSI in Darmstadt, Germany, and the
University of Twente in the Netherlands, who contribute
their experience in groupware [3] and workflow manage-
ment [14]. User partners are KPN Research in Groningen,
the research division of the largest telecom operator in the
Netherlands, and Church & General, an Irish insurance com-
pany that is part of the Allianz Group. Sema Group in
Madrid, Spain, acts as industrial observer in the consortium.
The CrossFlow project started in September ’98 and is
planned to run for two years. The project covers the com-
plete spectrum from requirements analysis to prototype
assessment in two real-world scenarios. Further information
on the CrossFlow project can be obtained via the project’s
web site [5].
This paper is organized as follows. In Section 2, we dis-
cuss the CrossFlow approach to cross-organizational work-
flow management, in which contracts play a central role.
Section 3 presents the CrossFlow contract model and lan-
guage. The CrossFlow architecture is discussed in Section 4,
outlining the support for basic cross-organizational work-
flow management. In Section 5, we present the advanced
aspects in workflow support, called the cooperation support
services. Section 6 gives a short overview of the CrossFlow
application scenarios. Work related to the CrossFlow project
is discussed in Section 7. We end this paper with conclusions
and a brief look into the future.
2. THE CROSSFLOW APPROACH
The CrossFlow project develops information technology for
advanced process support in dynamic virtual organizations.
Four main aspects characterize the CrossFlow approach:
• Dynamic service outsourcing. The cooperation between
partners is based on a dynamic service outsourcing
paradigm with service consumers and service providers.
Compatible business partners find each other through a
matchmaking facility based on trading technology.
• Contract-based service specification. A detailed service
specification in the form of a contract is the basis for a
tightly-linked cooperation implementing the service pro-
vision from service provider to service consumer. The
definition of the interaction in the contract is independent
of the specific enactment technology of the organizations.
• Fine-grained, advanced interaction. The interaction level
between service consumer and provider is at a fine-
grained and a high semantic level, enhanced by the avail-
ability of a set of advanced cooperation support services.
• Contract-dependent generation of enactment infrastruc-
ture. The enactment infrastructure that connects the infor-
mation systems of service provider and consumer is
dynamically set up according to the contract and a specifi-
cation of the way the contracted service is to be imple-
mented and supervised.
Figure 1 illustrates the CrossFlow approach. In this figure,
we see how the service consumer outsources its activities D
and E to a service provider that can perform these activities
with an additional value (hence D+ and E+). The contract is
the basis for the cooperation that, apart from service invoca-
tion and result reception, also encompasses detailed monitor-
ing and control of the outsourced activities.
The first three aspects above are of a conceptual nature. In
the sequel of this section, we will discuss these in more
detail. The contract framework is further elaborated in Sec-
tion 3. The fourth aspect above is of an architectural nature
that we discuss in Section 4.
Note that the trading-based approach to service outsourc-
ing means that CrossFlow can be considered a project inves-
tigating the intersection of workflow management and
electronic commerce technology.
2.1 Dynamic service outsourcing
The CrossFlow approach to cross-organizational workflow
management is based on a dynamic service
consumer/provider paradigm. This means that an organiza-
tion that wants a service to be performed on its behalf (the
278 computer systems science & engineering
P GREFEN ET AL.
Figure 1 Dynamic service outsourcing in a virtual organization