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

 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-

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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

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.

References

1. Grudin J.: Computer-Supported Cooperative Work: History and Focus. IEEE Computer,

27(5) (1994), 19-26

2. Booth D., Haas H., McCabe F., etc.: Web Services Architecture. W3C Working Group Note

(2004)

3. Fuks, H., Gerosa, M.A. and Lucena, C.J.P.: The Development and Application of Distance

Learning on the Internet. Open Learning - The Journal of Open and Distance Learning, 17(1)

(2002), 23-38

4. Miller J.H., Moser, S.: Communication and Coordination. Santa Fe Institute Working Pa-

pers (2003)

5. Kogiomtzis G., Martakos D.: Integrating Heterogeneous Communication and Messaging

Systems in an Object-Oriented Middleware Framework. Proceedings of the 8th Interna-

tional Conference on Object-Oriented (2002), 488-493

6. Rosenberg J., Schulzrinne H., and Camarillo G., etc.: SIP: Session Initiation Protocol. IETF

RFC3261 (2002)

7. Bellas, F.: Standards for second-generation portals. Internet Computing, IEEE, 8(2) (2004),

54-60

8. Gudgin M., Hadley M., Mendelsohn N., etc.: Simple Object Access Protocol (SOAP) 1.2.

W3C Recommendation, 2003

9. The Parlay Group: Parlay Web Services Overview. The Parlay Group Specification (2002)

117