A Web Services based Communication Services
Framework for Collaborative Work
Jun Liu, Bo Yang, Wei Lu
IBM China Research Lab
100085 Beijing, China
Abstract. This paper considers the problem of integrating communication ser-
vices that support group collaboration systems. Past experience has shown that
heterogeneous communication services are extremely difficult to be integrated
into collaboration environment and extended to meet continuous changing re-
quirements. This paper aims at proposing a common, interoperable framework
based on Web Services technology for integrating communication services in a
collaboration environment. This framework allows the implementation of reus-
able communication services components that can be plugged into the collabo-
ration system and be invoked on demand according to communication require-
ments of collaboration applications. Based on this framework, a prototype sys-
tem called Rich Media Collaborative Workplace is developed. This system pro-
vides an integrated collaborative workplace with benefits of increasing produc-
tivity, saving cost and improving efficiency.
1 Introduction
In today's extremely competitive environment, success of business is the result of
collaboration of corporate groups. Efficient collaboration relies on effective commu-
nications. With the information technology revolution, computer supported collabo-
rative work (CSCW) [1] system becomes the popular tool to support people work
together anywhere and anytime to solve a common problem. A typical CSCW sys-
tem integrates the control and presentation of heterogeneous types of data channels,
such as text, image, audio and video, to enhance the quality of distributed collabora-
tive work. From the perspective of communication services, CSCW system has a
broad range of requirements. In the last decade, enterprises focus on building com-
munication infrastructures in order to meet the ever-increasing requirements for intra-
enterprise and inter-enterprise communications. In this perspective, enterprises have
brought together various communication technologies and applications to facilitate
and improve the collaboration. Hence at present most collaboration systems must
adapt a heterogeneous communication environment, which are not designed in the
approach of a unified communication subsystem. It will bring substantial benefits to
users if we can build an integrated communication services environment for collabo-
rative work system, which combines various communication services as well as other
collaboration applications into a single easy-to-use environment. Therefore, it is
Liu J., Yang B. and Lu W. (2005).
A Web Services based Communication Services Framework for Collaborative Work.
In Proceedings of the 2nd International Workshop on Computer Supported Activity Coordination, pages 109-117
DOI: 10.5220/0002540401090117
Copyright
c
SciTePress
important to create a more general framework to integrate wide range of communica-
tion services into a collaborative work system.
In this paper, we define such a common, interoperable framework based on Web
Services [2] technology for integrating communication services in a collaboration
environment. Based on this framework, we developed a Rich Media Collaborative
Workplace system, which integrates various communication services including in-
stant message, email, telephone and audio conference in a heterogeneous environ-
ment.
The remainder of this paper is organized as follows: Section 2 introduces the moti-
vation of building a Web Services based framework of communication services for
collaborative work. Section 3 describes the communication services framework for
collaborative work. Section 4 introduces the implementation of Rich Media Collabo-
rative Workplace system as the prototype. The conclusion is given in section 5.
2 Using Web Services to Build a Communication Services
Framework
2.1 Collaborative Work Model
To achieve a goal with a collaborative approach, people need to cooperate towards a
common purpose, to coordinate for organizing themselves and to communicate for
exchanging thoughts. These three concepts, cooperation, coordination and communi-
cation, consist the 3C model (Figure 1) for collaborative work [3]. They surround the
working group, which is the centric role of this model, to provide desired services for
collaborative work.
Fig. 1. 3C Model for Collaborative Work
Cooperation services provide means for a group of people working together to-
wards a common purpose. It support users with the mechanisms and means they
need in order to perform their collaborative tasks within dislocated working groups.
Members of groups could be spatially separated from each other. The inter-member
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cooperation is implemented by means of groupware, which are combinations of soft-
ware and hardware that efficiently support group people in their collaborative works.
There are two essential factors for successful cooperation: well-understood goal and
organized process. They are ensured by communication and coordination services.
Coordination services provide means for organizing working group members and
bringing them order. Coordination service is accomplished by one entity (known as
the coordinator) disseminating coordination context to group members to complete a
task corporately. From previous research work [4], we can that the ability of group
members to reach and maintain a superior coordination relies on the efficiency of
communication service. And the performance of coordination can be improved by
increasing the potential of using communication services.
Communication services provide group communication facilities to working mem-
bers for transmitting and exchanging information. These services include: text-based
instantaneous exchange of messages (Instant Message Service), individual electronic
mail exchange (E-Mail Service), peer-to-peer voice-based conversation (Telephone
Service), prearranged or ad-hoc meeting for discussion (Conference Service), etc.
Communication services are important for collaborative work. Working group mem-
bers must share information as widely as possible. Effective communication helps
members understand how their works fit the objective and perform collaboration
work in order. Otherwise, individuals in a working group tend to work independ-
ently, often in conflict with one another.
Thus, we can say that communication is the foundation for collaborative work. It
is the basic element and provides support for cooperation as well as coordination.
2.2 Challenges to Communication Services
Development of communication services in collaborative work environment is evolv-
ing quickly. At the same time, challenge of heterogeneity to communication services
also comes out. In the last decade, computer supported communication improved the
performance of collaborative work by enabling working group to collaborate in ways
of distributed cooperation. Therefore, there are a large number of communication
systems are built to meet the ever-increasing user requirements. In these systems,
there are various communication technologies and applications exist to facilitate and
improve the collaboration. This situation brought the big challenge of heterogeneity
to communication services for collaborative work system [5]. The heterogeneity is
represented not only by the variety of hardware, operating system platform, pro-
gramming language, but also by the diversity of underlying communication protocol,
software architectures and models. This heterogeneity is the barrier to services inter-
operability and usability. It causes different perspectives and needs for cooperation
and coordination services, which leads to incompatible design specifications for col-
laboration workspace solutions. Hence, developers of collaboration systems usually
face this complex problem which must be efficiently solved. It is desired to build an
integrated communication services environment for collaborative work system, which
is easy to combine various communication services as well as other collaboration
applications into a single easy-to-use environment.
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2.3 Using Framework as a Solution
Above subsections indicated the heterogeneity challenge of communication services
for collaborative work, which brought the complexity problem to developers of col-
laboration system. Managing this complexity in collaboration system development is
essential for the success of the system. Here we propose to use a Communication
Services Framework (CSF) to support integration of communication services in the
development and implementation of a collaboration system. The CSF makes it easier
to integrate sophisticated communication services supporting collaborative work.
The CSF seeks to abstract the developer from the specifics of the underlying commu-
nication services platforms, applications and protocols. It eliminates the need for the
developer to fully understand the detailed operation, configuration and integration of
communication services in a collaborative environment. Thus, making use of the
CSF can simplify the design, development and implementation of collaboration sys-
tem. Developers can use it to accelerate the development process, leading to shorter
time, lower cost, higher product quality and stronger competitiveness. To achieve
this, the framework should have the following features:
- Integration solution for consolidation of heterogeneous hardware, software and
protocols.
- Flexibility architecture for combination different communication services to meet
various requirements.
- Standard-based interface for interoperation between different technology vendors.
2.4 Web Services: the Best Choice
We proposed our new concept that is to combine different communication services
into a collaborative environment using an integrated communication services frame-
work above. This framework should have following capabilities: integration, flexibil-
ity and standardization. From those perspectives, Web Services [2] seems to be the
best candidate for this framework.
Web Services is a standard technology of integrating Web-based applications us-
ing a set of open standards (XML, SOAP, WSDL and UDDI) over an Internet proto-
col network. Web Services provide a way to describe and publish application’s inter-
faces to allow client applications invoke them. It supports different applications from
different sources to communicate with each other. Following benefits from Web
Services make it as the best choice to be used to build the communication services
framework for collaborative work.
- Web Services is a simplified solution to integrate applications regardless of the
device, platform and protocol that they use. Web Services works with standard Inter-
net and Web protocols such as TCP/IP, HTTP and XML. The Web infrastructure is
widely built in a significant number of companies for collaboration system. People
have had sufficient knowledge and experience in using and managing it. So Adopt-
ing of Web Services can potentially improve collaborative process efficiency and
reduce IT implementing cost.
- Web Services is designed as a flexible solution with loosely coupled feature. By
adopting XML protocol, Web Services allows applications written in different lan-
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guages on different platforms to communicate with each other in a standard way. So
it is an ideal technology to orchestrate various information exchanging processes for
supporting collaborative work.
- Web Services is based on industry standard protocols with universal support.
The full life cycle of Web Services are covered by standards including describing,
publishing, discovering and invoking. It makes Web Services to support the devel-
opment of interoperable applications across a wide array of environments. The open
standards help to reduce technology cost and increase service quality by wide choice
of suppliers.
3 Web Services based Communication Services Framework
With the framework concept and benefits of Web Services, we propose a Web Ser-
vices based Communication Services Framework (WS-CSF) to support integration of
communication services in the development and implementation of a collaboration
system. Figure 2 shows the five-layer architecture of WS-CSF framework. They are
transport layer, access layer, collaborative presentation layer, mediation layer and
communication middleware layer. The WS-CSF allows the implementation of reus-
able communication services components that can be plugged into the collaboration
system and be invoked on demand according to aommunication requirements of col-
laboration applications. In this framework, communication services are wrapped into
an independent component to hide the complexity of underlying communication net-
works, platforms and protocols. This component exposes a defined set of Web Ser-
vices interfaces to use supporting communication services, such as message, tele-
phone and conference services.
Fig. 2. WS-CSF Framework
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Access Layer: This is the application interface layer for end users. This layer pro-
vides user interaction interfaces with the collaboration system. It contains different
kinds of application endpoints to participate collaboration sessions, such as computer,
telephone and PDA. Since different application endpoints have their own signaling
and media protocols for participating, we abstract them as an access interface be-
tween access layer and transport layer.
Transport Layer: This layer is the carrier component to interconnect other layers.
It provides capabilities to reliable transmit information from a source to single or
multiple destinations. This layer comprises a collection of transportation networks,
such as IP network, Public-Switched Telephone Network and Mobile network. Each
network is responsible for supporting a communication service to meet a specific
requirement.
Collaborative Presentation Layer: This layer provides a collaboration portal to
end users for the aggregation of different collaboration services. It is a container of
various collaboration applications for collaborative work. The main concerns of this
layer are the representation of collaborative information and integration of various
collaboration methods. It takes care of visualizing the collaboration service interfaces
to the user in a way that is adapted to the application endpoint that the user is used.
Users can customize the layout of their collaboration portal. With this layer, it is easy
to integrate various collaboration services into a consolidated workplace. These ser-
vices can be installed and removed dynamically by using service configuration facili-
ties.
Mediation Layer: This layer is the mediator between collaborative presentation
layer and communication middleware layer. It brokers interconnections and bridges
communication services requestor and provider between these two layers. The pur-
pose of introducing this layer is to conceal the heterogeneity of communication ser-
vices by offering a unified interface. The main component of this layer is a Web
Services Bus. This bus offers an enhanced environment for conducting dynamic
communication services invocation with Web Services. It receives service requests
from requestor (i.e. applications in collaborative presentation layer) and dispatches
requests to corresponding service providers (i.e. servers in communication middle-
ware layer) to accomplish a communication process.
Communication Middleware Layer: Below the mediation layer, the communica-
tion middleware layer provides the core communication facilities to access supporting
communication services. It contains the engines of communication services. This
layer comprises a group of service server that is responsible for providing a specific
communication service. Each service server offers capabilities to collaboration appli-
cations for accessing underlying communication resources. These capabilities are
exposed as Web Services interfaces to be invoked through Web Service Bus in me-
diation layer. The service request conveyed in Web Services message is mapped to
specific protocol by service server and transmitted into transport layer.
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4 Implementation of a Prototype System
Based on WS-CSF, we have built a Rich Media Collaborative Workplace prototype
system that is used for worldwide collaboration work. This system integrated follow-
ing communication services into a single collaborative workplace: synchronous com-
munication for real-time interaction including voice-based (telephone) and text-based
(instant message), asynchronous communication for users not available simultane-
ously (email), pre-scheduled and ad-hoc voice conference and white board. Figure 3
shows the system architecture of Rich Media Collaborative Workplace.
Fig. 3. Rich Media Collaborative Workplace Architecture
We built a converged IP network based communication infrastructure as the trans-
port layer. In this infrastructure, we construct a SIP-based VoIP network to provide
voice communication capability for users. Session Initiation Protocol (SIP) [6] is an
application-layer control protocol for creating, modifying and terminating communi-
cation sessions with one or more participants. The SIP proxy and SIP/PSTN gateway
create a VoIP domain, which is bridged with traditional voice network, for voice
terminals to perform voice communication. Additional servers including media
server for voice mixing and LDAP server for user information storing provide sup-
plemental functions. The converged transport layer offers diversity data and voice
channels for user to access this collaboration system. Users can use computer, mobile
phone, PSTN phone, softphone and SIP phone to access collaboration services.
We implemented this system using a flexible componentized architecture, which
makes it easy for using, managing and extending. The system provides a collabora-
tion portal to users to aggregate different collaboration services into a single work-
place. It is built based on a portal server which contains various collaboration port-
lets [7] for each collaboration services. Users can customize their collaboration por-
tals by adding and removing collaboration portlets and changing the layout of their
workplace portal. With the power of portlet administration tool, the system adminis-
trator can easily integrate various communication services into workplace by dynami-
115
cally installing and uninstalling portlets. In addition to existing Domino portlet for
email and Sametime portlet for instant message, we developed two kinds of portlets
for telephone call control and conference services. These two portlets are built with
Web Services adaptor for encoding and decoding request to SOAP [8] message.
Through the SOAP connection on mediation layer, the collaborative workplace portal
can invoke Web Services provided by service servers in communication middleware
layer. We implemented two communication middleware servers by leveraging Parlay
Web Services technology [9], which is a set of standard APIs that enable third party
to access resources of communication network. After receiving request routed from
mediation layer, communication service server translates the high-level commands to
signaling messages of underlying protocol (i.e. SIP messages) and sends them to
corresponding collaboration clients or feature server through transport layer.
With this system, we provide an easy-to-use web interface for users to perform
collaborative work. In addition to text message and email, users can start voice con-
versation and conference by a single-click through workspace portal. Figure 4 shows
the scenario of using this system. We can see that a user invite another user into a
voice conference by choosing an option of context-aware menu through clicking
people’s name. And the conference status can also be seen in a popup window.
Instant Message
Email
Conference
Fig. 4. Usage Scenario of Rich Media Collaborative Workplace
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5 Conclusion
For years, computer supported communication services have been converged into
collaboration systems. It is changing the way how workers interact and perform
collaborative work. By adopting enhanced communication services, companies can
improve efficiency of collaboration and increase productivity for business growth. In
this paper, we presented a Web Services based Communication Services Framework
(WS-CSF) to support integration of communication services in the development and
implementation of a collaboration system. This framework has five-layer architecture
to solve the heterogeneity problem in a collaboration environment. Under the WS-
CSF framework, various communication services can be integrated into a single col-
laboration workplace to meet various communication requirements. Based on this
framework, we have developed a prototype system called Rich Media Collaborative
Workplace. This collaboration system provides an integrated collaborative work-
place with multiple communication channels including instant message, email, tele-
phone and audio conference. It can benefit users by increasing productivity, saving
cost and improving efficiency.
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