OPUCE: A telco-driven service mash-up approach

◆ OPUCE: A Telco-Driven Service Mash-UpApproachJürgen Sienel, Alberto León Martín, Carlos Baladrón Zorita,Laurent-Walter Goix, Álvaro Martínez Reol, and Belén Carro Martínez

Telecom operators are facing major business challenges as Internetplayers are becoming an increasing threat in both new and traditionalcommunications markets. Technologies like Web 2.0, Session InitiationProtocol (SIP), and peer-to-peer (P2P) allow for easy integration ofcommunication features in social networking applications. IP MultimediaSubsystem (IMS) is a proposed solution from the telecommunicationsindustry, but its architecture is complex and costly and still doesn’t offer theInternet world the flexibility that end users expect. The Sixth FrameworkProgramme (FP6) of the Information Society Technologies (IST) IntegratedProject (IP) Open Platform for User-centric service Creation and Execution(OPUCE) addresses these challenges from a technical and business perspective.In this paper, we describe the OPUCE service execution architecture, which isdesigned to allow interoperation of telco and information technology (IT)applications in a seamless event-driven manner, and the service creationworkbench that enables end users to build their own personalized servicemash-ups and share them with the community. © 2009 Alcatel-Lucent.

For instance, Voice over Internet Protocol (VoIP) tech-

nology seems to be a promising and cheap alterna-

tive to traditional voice services.

Hence, operators have been pushed to explore

new opportunities such as content provisioning, to

expand their offers in order to sell value-added ser-

vices that would lead to higher profit margins [8].

However, while telcos have been making huge net-

work investments and migrations for years, new IT

competitors can offer similar services in the near

future, more closely integrated with the plethora of

information services available on the Web.

IntroductionThe current landscape for traditional services in

the telecommunications market is not very pleasant

for operators. The perceived value of pure transport of

voice and data has been decreasing continuously, to

the point where it is now almost considered to be a

commodity. Additionally, a new wave of threatening

competitors are ready to enter the communications

market with breakthrough technologies and services:

information technology (IT) companies have realized

that they can provide similar communication services

at lower costs over the Internet, offering even more

functionalities than their established telco counterparts.

Bell Labs Technical Journal 14(1), 203–218 (2009) © 2009 Alcatel-Lucent. Published by Wiley Periodicals, Inc.Published online in Wiley InterScience (www.interscience.wiley.com). • DOI: 10.1002/bltj.20363

204 Bell Labs Technical Journal DOI: 10.1002/bltj

Telcos have some advantages over their IT coun-

terparts: extensive knowledge of the customer base

and established communication infrastructures that

can easily serve hundreds of million of users. However,

the prospect of identifying one specific service that

converts those advantages into global business suc-

cess is indeed more difficult than expected. Telcos can-

not afford to wait until a “killer application” (a service

that, on its own, generates enough revenue to sus-

tain a market and justify technology investments)

appears. The concept of a killer application attractive

to all has become obsolete, as thousands of new ser-

vice ideas—each with its own niche market—emerges

from the Internet each year.

Telcos are searching for another way to harness

the infrastructures and the information they own, in

order to gain an edge in the market for next-generation

communication services by offering attractive products.

One possible answer is found by addressing the “long

tail” [2]: it is more attractive to offer thousands of ser-

vices where each user finds the precise service he or she

needs than to offer a few services for a huge number of

people. But how will telcos succeed in the great effort

required to analyze customer preferences, and to

design and deploy each specific service?

Paradoxically, an answer can be found by looking

at the model that the Internet has followed during

the last few years in order to be able to offer content

and services for everyone: Web 2.0. In this symmetri-

cal paradigm, the Web is no longer a distributed infor-

mation storage vehicle through which Webmasters

push content towards users, but instead, a dynamic

environment where users are now content creators

and consumers at the same time. Users publish and

share their own content and organize themselves in

communities, thus providing everyone with the exact

information he or she is looking for. It is the key fac-

tor behind the success of sites such as YouTube* or

Wikipedia. Web 2.0 has so deeply impacted society in

general and the IT community in particular that the

“Person of the Year” named by Time magazine for

2006 was actually “You” [11]. The magazine had a

mirrored cover page to underscore the fact that the

user has become the “center” of the Web, providing

and consuming content at the same time, and thus

acting as a “prosumer.”

Panel 1. Abbreviations, Acronyms, and Terms

API—Application programming interfaceBPEL—Business Process Execution LanguageBT—British TelecomConteXtML—Context Markup LanguageEMMUS—European MultiMedia Usability

ServicesFP6—Sixth Framework ProgrammeIM—Instant messageIMS—IP Multimedia SubsystemIP—Internet ProtocolISO—International Organization for

StandardizationIST—Information Society TechnologiesIT—Information technologyJ2EE—Java 2 Enterprise EditionJAIN—Java API for integrated networksOMA—Open Mobile AllianceOPUCE—Open Platform for User-centric service

Creation and ExecutionP2P—Peer-to-peer

PDA—Personal digital assistantREST—REpresentational State TransferRSS—Really Simple SyndicationSCE—Service creation environmentSEE—Service execution environmentSIP—Session Initiation ProtocolSLA—Service level agreementSLEE—Service logic execution environmentSLM—Service lifecycle managerSME—Small and medium-sized enterpriseSMS—Short message serviceSPICE—Service Platform for Innovative

Communication EnvironmentUGC—User generated contentUGS—User generated servicesUIM—User information managerVoIP—Voice over Internet ProtocolWS—Web servicesXDM—XML Document ManagementXML—Extensible Markup Language

DOI: 10.1002/bltj Bell Labs Technical Journal 205

More recently, Web 2.0 has expanded to enable

end users to generate not only content, but also ser-

vices in the form of mash-ups—small applications cre-

ated by interconnecting smaller Web services with

each other. For example, it is possible to link an online

database with the popular Google* Maps service in

order to show the location of the most popular restau-

rants in a geographic area. Some graphical tools, such

as Microsoft Popfly*, have been launched to support

the creation of these mash-ups. Without requiring

programming skills, they let all end users create the

specific Web mash-up they need.

Open Platform for User-centric service Creation

and Execution (OPUCE), a 9 million euro integrated

project co-funded by the European Commission

under the Sixth Framework Programme (FP6), aims

at porting this user-centric philosophy into the telco

world. It provides the tools necessary to allow every-

one to build his or her own communication services

without having a specific background in computing.

In addition, it relieves telcos from the pressure of find-

ing a “killer application” in next-generation services

and simply allows users to build their own, completely

tailored to their needs.

Following this approach, there is no need to

spend resources in polling and studying end users to

discover the applications they demand, nor in build-

ing those applications. On the other hand, it is essen-

tial to rely upon user-friendly service creation tools,

an infrastructure to automate the service manage-

ment processes, and a safe execution environment

which guarantees data privacy as well as the integrity

of the operator’s network and resources [10, 14].

The OPUCE platform integrates all of the ele-

ments shown in Figure 1:

• Service creation environment (SCE), including Web-

based and mobile graphical service editors which

employ drag-and-drop operations and allow ser-

vices to be created as a composition of basic build-

ing blocks known as base services.

• Service lifecycle manager (SLM) to automate the

deployment and management of services and

resources.

• Service execution environment (SEE) designed to

orchestrate base services safely.

In addition, OPUCE is not restricted to the telco

domain. It has been designed as a union point of the

Web and communication services, a step forward in

the convergence of both worlds that is now being pur-

sued. With OPUCE, traditional information services can

be merged with communication capabilities, resulting

in an integrated and enriched experience for the user.

This is achieved using standard Web services middle-

ware, which permits the interaction of heterogeneous

components from both worlds.

Finally, OPUCE is an open platform. A key factor

in the Web’s success is that it is a completely distributed

and open system, composed of an enormous number

of independent nodes that can interact and offer all

types of services. Since no one controls the whole sys-

tem, the Web is incredibly flexible, constantly adapting

itself to fulfill a wide variety of purposes. OPUCE also

aims at porting this open philosophy to the telco world,

where operators have traditionally been reluctant to

forfeit control of their networks. The secured SEE

allows external providers to offer their services through

the operator’s infrastructure, where they can interact

with other OPUCE base services.

This paper is organized as follows. First, a study of

the current business environment of user-generated

services (UGS) is discussed. Then, we present the

SCE—the set of tools offered by OPUCE that allow

end users to build and personalize their services.

Following that, the two modules that allow the man-

agement and execution of services inside the OPUCE

platform are described—the service lifecycle manager

and the service execution environment. Finally, plat-

form validation results and conclusions are presented.

Business Environment: UGS and Potential NewRoles for Operators

Telecommunication networks and the Internet

have, until recently, existed as two completely sepa-

rate worlds, and so have their business models. While

telco services are provided directly by operators in a

closed environment, sometimes called the “walled gar-

den,” Internet services are traditionally offered by ser-

vice providers in a much more open way, sometimes

supplying third parties with open access to their appli-

cation programming interfaces (APIs). In their will to


adopt the Internet model, many operators are trying to

replicate the Web 2.0 paradigm in telecommunications,

the so-called Telco 2.0 concept. One of the most rele-

vant experiences in this new field is BT’s 21st Century

initiative [6]. BT has released a series of “open” APIs, so

that third parties can have access to operator services

and provide their own communication services. This

type of initiative is being adopted by companies such

as Orange, Telefonica (Open MovilForum [15]),

Telecom Italia, Deutsche Telekom, and Vodafone.

In this context, the appearance of initiatives mix-

ing telco and Web capabilities was quite predictable,

since both worlds are working toward a more open

and “user-centric” environment. Recently, proposals

have been announced such as Broadsoft’s Xtended,

which aims to add voice capabilities to Web mash-ups,

and Apple’s* iPhone* APIs for mixed services creation

(Web � telco). Ongoing innovative projects funded by

the European Commission, such as OPUCE, which

is the focus of this article, and Service Platform for

Innovative Communication Environment (SPICE)

[17], are also targeting these Web � telco mash-ups.

These initiatives are prompting a migration from

the user-generated content (UGC) era to the user-

generated services era, where end users are not only

content creators but also service creators. This evolu-

tion is highly relevant from the business model per-

spective. In contrast to content, which is generally free,

services usually have an associated cost. Thus, there

are some key issues that should be taken into account:

• Business view. The key question is: Could creation

and consumption of highly personalized and

Service executionenvironment (SEE)

Service creationenvironment (SCE)

Web:

AmazonGoogle† MapsYouTube†

Operator’sinfrastructure:

Call controlSMS sendingLocation

Third partyservice provider

Service lifecyclemanager (SLM)

OPUCE

End user

†Trademarks of Google, Inc.

OPUCE—Open Platform for User-centric service Creation and ExecutionSCE—Service creation environmentSEE—Service execution environmentSLM—Service lifecycle managementSMS—Short message service

Figure 1.OPUCE high-level scheme.


customized services, even when devoted to a spe-

cific and narrow audience, be relevant from a busi-

ness perspective? This question is answered by the

long tail paradigm proposed by Chris Anderson in

2004 [1], which explains how significant revenues

can be when obtained in a large number of small

amounts. In such an approach, it is crucial to keep

the costs of creating/providing those services to a

minimum. This requires the end users to create

services on their own and requires automation of

the deployment and maintenance for these ser-

vices in the platform.

• User demand. It is necessary to include end users in

the creation process (even integrating them in the

value chain as creators and consumers, i.e., pro-

sumers) in order to synchronize an offer with cus-

tomer demands. The goals are to lower the

barriers to participate in the service developer

community, to identify user needs directly, and

to use crowd intelligence to build solutions.

• Telco and Internet convergence. As previously men-

tioned, a remarkable difference between the two

worlds is the underlying business model approach:

telecom operators usually deal with associated

costs, whereas offering capabilities for free is the

common rule on the Internet. How, then, can

both strategies be combined? Noted industry ana-

lysts such as Forrester [18] suggest that the opera-

tors should “change their mindset” and replicate

the usual Internet model by coming up with alter-

natives (advertising, for instance) to obtain reve-

nues. Chris Anderson has proposed a witty model

called “Free!”[3], which emphasizes the impor-

tance of providing services to end users for free.

The model does not suggest that companies

should forget about making a profit, just that

companies have to get it from other indirect

sources.

These experts propose a series of alternatives that

can be grouped into six categories:

1. “Freemium.” The freemium concept reflects the

duality between basic and premium users. The lat-

ter are those who pay for a more exclusive service

including additional facilities. The same model can

be used when operators offer free basic services

in concert with others offering a certain added

value that makes them unique and for which the

user would agree to pay a fee.

2. Advertising. Benefits are obtained from advertis-

ing. The advertiser pays, not the end user.

3. Cross-subsidies. This is the well-known formula of

getting something for free while paying for

another product or service. This model became

very popular with the mobile telephony boom;

e.g., terminals were offered for free when sign-

ing a service contract with a particular mobile

operator.

4. Labor exchange. In this model, services are offered for

free, but in return the provider obtains some infor-

mation regarding user interests (e.g., a profile).

5. Altruism and zero marginal cost. This refers to the

possibility of offering services free of charge as a

result of pure altruism or just because they have

no real cost to the provider.

6. End user satisfaction. Finally, end user motivation

is a key point to be considered. Why do users

find it interesting to create their own services?

Furthermore, what encourages users to publish

those services so that others can consume them?

On one hand, a key social factor is prestige, which

is quite usual within the peer-to-peer (P2P) and

Web 2.0 worlds. On the other hand, profit can also

be considered, where a part of the benefits gener-

ated are shared with the end user, as would be

done with a legacy telco service provider. This

revenue sharing concept is quite an innovative

idea that is just gaining traction at companies like

Virgin, with its Virgin Mobile Studio V initiative.

Another example is the Apple AppStore, where

fees for downloading applications are directly for-

warded to the application creators, with a 30 per-

cent reduction. A percentage is retained by Apple

for hosting and distribution.

The aforementioned “Freemium” strategy and the

advertising model-as-revenue source are seriously

being considered by telco operators to avoid being

relegated to the role of a simple connectivity provider

(known as a “dumb pipe”). Those models, together

with the possibility of obtaining revenue from hosting

and distribution of services, could be the pillars for a


new role played by operators. Their implementation is

under consideration for a potential market version of

OPUCE.

Finally, the OPUCE platform is structured in sev-

eral modules that can potentially be exploited as a

whole and/or individually. In this sense, an essential

part could be released under some kind of open

source license in order to involve the developer’s com-

munity. For instance, all the modules related to opera-

tor network resources management and protection

would remain private, while some service editors

could be released as open source.

Giving Control to End UsersWithin the concept of user-centric service creation,

a paradigm shift is occurring, since service creators

are not specialists or professionals. Instead these end

users often have little knowledge or background in

computer technologies. This role change imposes

some constraints upon the service creation environ-

ment. As traditional SCE interfaces are difficult to

handle for average users, the entire creation process

needs to be supported via intuitive graphical wizards

or assistants.

The analysis and definition of a user-centric SCE

require a study that goes beyond functional specifica-

tion, such as the editing metaphors necessary to make

end users feel comfortable with the design process,

security, and limitation concerns. In particular, the

following topics need to be addressed:

• Language. In a global context such as the Internet,

users interact independently of geopolitical barri-

ers. Hence, interfaces for creating, sharing, and

editing another user’s service need to be interna-

tionalized and easily understood in the end user’s

own language.

• User sphere. Reference to personal information at

creation time has to be abstracted to reflect a “me-

centric” concept of “my phone number” or “my

wife’s e-mail.” At execution time, this abstract

representation will be translated into the actual

information of the user invoking the service, who

may be different from the original creator.

• Assistance. Apart from online help to assist the user

in the creation process, editing tools must provide

intelligent features that automatically perform

complicated actions.

• Seamless access. Similarly to service execution, ser-

vice creation by end users needs to be ubiquitous

and adapted to the current user conditions.

• Validation. Services created by end users may

potentially harm the platform, so it is necessary to

introduce validation mechanisms to ensure that

services are safe.

• Extensibility. Users are more motivated to create

services if the set of base services they can com-

pose is large and diverse. Hence, the service crea-

tion process must support the provisioning of new

base services for enriching this set, whether cre-

ated by end users themselves, or commercial third

parties.

User Generated Services: New Roles for End UsersOne of the main aspects of Web 2.0 [16] is that

users are able to add value to the services offered.

Rich Web-based interfaces, communities, and social

networks are just a few examples of how users are

continuously stimulated to remain active. Sharing

services, voting, and social reputation can be effec-

tively applied to evaluate services and/or service crea-

tors and to stimulate users’ creativity.

Following the emerging concept of the prosumer,

two roles are identified for end users interacting with

a UGS platform:

• Service subscriber (consumer). After browsing a ser-

vice catalog or being notified when a new service

of interest has been created, this individual can

subscribe, start using the service, and potentially

personalize it as well.

• Service creator (producer). The service creator uses

the platform to create new services by combin-

ing base services (atomic enablers) and sharing

those composed services with the community.

However, enabling end users to create their own

services using attractive tools is not enough to create

a complete marketplace that stimulates them to join

and engage with the community. Incentives have to

be provided, and the progressive increase in the

number of producers can be envisioned as a step-

wise approach:


• Personalization. Most users begin to act as con-

sumers of available services and are interested in

using a service “as is” or with only minimal per-

sonalization/configuration.

• Create my own service. At this stage, the user starts

creating simple services that exactly fit his/her

needs for personal and private consumption and

are thus extremely personalized, although not

configurable.

• Share my services. The private consumption of self-

created services, if successful, can increase user

confidence with the system and speed its prolif-

eration across the user’s social sphere. Such usage

ultimately causes the user to share the service

with friends and any other user in the community

who may be interested in using (or personaliz-

ing) it. This transition may be based on some

incentives, either to become known, to pioneer,

or to obtain some tangible reward (i.e., money,

based on revenue sharing models).

Service Editing in OPUCEAccording to project goals, the OPUCE service

creation environment is ultimately addressing a wide

population of users who create new services or per-

sonalize existing ones.

The OPUCE SCE includes a mobile editor and a

Web editor. The Web editor is a Web-based interface

embedded in a community portal. The mobile editor is

a local application on the user’s terminal (e.g., per-

sonal digital assistant [PDA]) with simplified features

and user interface. Both editorial interfaces share the

same philosophy for service creation based on a ser-

vice composition paradigm: the end user will be

assembling base services that will be connected and

configured to define the service flow (as Lego* bricks

create a final construct). This approach is similar to

one employed in current mash-up tools like Yahoo!*

Pipes and offer a palette of building blocks that com-

prise base services, which users drag and drop onto

an editing canvas before linking inputs and outputs

to compose a workflow.

One of the challenges in the editing process

for OPUCE is to define telco services whose intrinsic

characteristics require support for event-based flows.

Events received from the network must be managed

with simple graphical representations through han-

dlers that manage events occurring in the network

and actions to take upon them.

Each base service exposes a set of properties and

actions and fires a set of events, while service com-

position occurs by linking events with actions. For

example, by linking a base service that fires the event

“when-SMS-is-received” to the action “make-video-

call,” one produces a service that automatically initi-

ates a video call whenever an SMS is received.

Properties are used to configure base services and

share information between them.

The output of the Web or mobile editor is a ser-

vice description [5]—an XML document that stores

all of the information required by the platform about

the new service: the graphical layout in the SCE,

semantics, and the service logic. As both editors share

this service description, it is possible to modify a ser-

vice created with one editor by using the other.

Web editor. Figure 2 provides a snapshot of the

OPUCE Web editor highlighting its main sections.

The figure shows a very simple example flow

that helps a user retrieve an important e-mail when

he/she is not at the desk, either by getting notified

via short message service (SMS) or through a voice

call depending on his/her current context. The

semantics of the service are not relevant; however,

the graphical representation of the base services and

their connections inside the composition are

essential for usability purposes. As previously men-

tioned, a proper choice allows the service composi-

tions created to be read with a sentence. Referring to

the earlier example, “When e-mail is received then

get context; when context is found and X then start

call; otherwise send SMS to user,” it is quite evident

how multi-language support greatly improves the

overall solution.

Another point revealed by the example is that

using the proposed notation, the designer does not

need to worry about synchronous or asynchronous

(event-based) interactions: each block can manage

events (internal or external) through specific handlers

that allow the drawing of outgoing arcs.


Mobile editor. Coupled to the Web editor described,

the mobile editor shown in Figure 3 targets simple

terminals and provides most of the capabilities of the

Web editor. The mobile editor’s main attribute is

“minimal user interface” based on “automation by

default,” which means that by default the user deals

only with higher level aspects of composition, and

editor automation tries to provide the lower-level

aspects without user interaction.

At a high level, the mobile editor manages a list of

base services that the user wants to combine. Depending

on the device capabilities, this list may be a chain of

boxes or a simple text list. In both cases, the list is

navigable to access details of each base service, such as

inputs, outputs, and configuration.

Editor automation tries to fulfill all detailed

aspects of each base service in real time, mainly using

type matching of inputs and outputs, or adding adap-

tation base services when no direct connection is

available. Further configuration and inputs may auto-

matically refer to the user information.

The status of an element connection is graphically

highlighted, so that the user editing the service is aware

of the status of the composition process and has the

potential to control some detailed aspects manually.

The mobile editor has some limitations with

respect to the Web editor, namely, that it does not

allow conditional flows. Hence, a service created in

the Web editor may not always be editable in the

mobile editor.

Enabling Personalized ServicesTelco knowledge of their user base—namely, pro-

file, preferences, or context data such as location or

presence—is a key driver toward the personalization of

services in a highly automated manner, which can

already be supported at the service creation level,

besides its operation at execution time. OPUCE sup-

plies this information through the user information

manager (UIM), a distributed infrastructure that stores

and manages user identity, profile, and context, relying

upon standards such as Open Mobile Alliance* (OMA)

XML Document Management (XDM), Diameter, and

Context Markup Language (ConteXtML) [13]. The

OPUCE portal and client applications allow the editing

and publication of this information to the UIM.

RSS—Really Simple SyndicationSMS—Short message service

Figure 2.A snapshot of the Web editor.


Leveraging this feature, OPUCE embraces three differ-

ent ways to achieve this personalization:

• Workflow adaptation. The “context” base service

retrieves context information from the UIM [13].

Based on this information, the service creator can

use “if…then” blocks to define separate branches

of the workflow depending on the context of the

end user.

• Context-aware base services. Some base services are

intrinsically designed to retrieve context infor-

mation and react accordingly. For example, a

message sender base service internally retrieves

presence information and could send an instant

message (IM) if the user’s presence status is online

or send an email if it is not.

• $me. The $me construct virtually represents the

user’s personal information to be resolved at exe-

cution time—namely, the identity, profile, and

context variables stored in the UIM, such as

$me.location or $me.my_wife_phone_number. The

use of $me properties as values of base service

properties in the SCE allows the personalization

of service behavior to whoever uses it, while

providing a me-centric view of the service for the

creator. For example, the “Send to:” property of a

“Send SMS” base service set to $me.phone_number

will at execution time be resolved into the phone

number of the end user invoking the service

pulled from his/her profile in the UIM.

Dynamic Execution Models for User-GeneratedServices

Along with the difficulties that may encompass

the exposure of the service creation process to end

users, another important challenge is the provisioning

of a scalable and secure service delivery platform and

execution environment for user-generated services.

In traditional telecommunication systems, the

platform resource requirements are calculated based

on the number of users, the number of provided

resources, and the network traffic generated, e.g.,

defined by the number of requests to a service or

resource. Typically, this is differentiated to identify the

floor traffic and peak traffic (e.g., during business

hours). The Erlang formula [4] is used to dimension

telecommunication systems, and it works well for pro-

visioning services such as call control, presence, Web

servers, or call center applications.

When applying this model to user-generated ser-

vices, a new dimension has to be taken into account—

the number of services, which may become infinite in

order to tackle the long tail of all possible applications.

OPUCE—Open Platform for User-centric service Creation and ExecutionSMS—Short message service

Figure 3.A snapshot of the OPUCE mobile editor.


The relevance of providing a huge number of ser-

vices when the number of users remains stable may

be something to be considered, but at least the distri-

bution of resources among the services will play an

important role, as the requirements for each single

service may not be as predictable as those for a fixed

amount of services.

When looking at user-generated content, peer-

to-peer systems play a more important role than

client/server based architectures, because of better

scalability and reliability. Within OPUCE, we have

been investigating the application of a dynamic and

distributed approach to service infrastructure. The

openness of the service environment requires man-

agement features that monitor the use of services and

resources in the execution environment. For each

base service, and subsequently each service composi-

tion, service level agreements can be defined. Those

can be either set explicitly from the creator in the por-

tal or derived, e.g., from the chosen business model.

The service level agreements (SLAs) will be used at

deployment and at execution time.

The OPUCE Service Execution ModelWhen defining the service composition and exe-

cution model in OPUCE, two important requirements

had to be considered. First of all, the composition

model needs to be easily understandable by end users

who have no or limited programming skills, and, sec-

ond, it must allow the seamless cooperation of telco

and IT resources.

As a result of the first requirement, the project team

decided to implement an event-driven, workflow-

oriented composition model. This model describes all

available base services by action/event patterns. Each

base service covers a single functionality by defining at

least one single but normally a set of correlated

actions that implement that function. Whenever such

an action is invoked, it will execute the function and

provide notification of changes with respect to the

execution state through the triggering of events. These

events are used in our model to invoke actions in

other base services or to terminate an ongoing service

composition session. We have chosen this model not

only because it is more intuitive to the end user for

service composition purposes, but also because it

coherently conveys concepts that are widespread in

the telecommunications world.

The second requirement is addressed by providing

an open service execution environment; it does not

stick to a single application server technology, but

seamlessly integrates the orchestration of services run-

ning on top of several technologies like Java* 2

Enterprise Edition (J2EE*), Java API for integrated

networks service logic execution environment (JAIN*

SLEE), Session Initiation Protocol (SIP) servlets, .NET

or client-side widgets. This gives base service develop-

ers the freedom to choose their preferred environment

to develop and deploy the base services. Base service

exposure follows the service-oriented architecture para-

digm, using the Web service protocol stack as the

interface between base services and the Business

Process Execution Language (BPEL) as the orchestra-

tion layer. While such a model is suitable for server-

based interaction, the inclusion of clients such as

mobile terminals, personal digital assistants, or laptop

computers is more difficult, due to the heavy protocol

stack. For this, we decouple the server side execution

via a proxy that plugs the client side components into

the Web services (WS) stack, while using more light-

weight communication models like REpresentational

State Transfer (REST) or Session Initiation Protocol for

communication with the client. This allows us to exe-

cute specific base services on the client terminals as

part of the execution platform, to reduce the load on

networks and network-centric resources, and to inter-

act with the end users via dedicated well-adapted

interfaces. We adopted state-of-the-art widget tech-

nology into the OPUCE service execution orchestrated

by SIP as a communication protocol.

Each base service is identified by a unique name

inside the platform and is specified by three sets of

elements:

1. Properties. Each property consists of a name (unique

within the base service) and a value; each base

service instance will manage its own properties,

keeping track of their values and updating them.

2. Actions. The actions describe the operations that a

base service can perform. The triggering of an

action might modify the state of the base service


instance. It is not mandatory that the actions are

independent. Constraints can be applied that

determine the sequence of the different actions.

After the invocation of an action, the base service

will fire one or more events.

3. Events. Events are the notifications sent to exter-

nal entities informing them of any change of state

or of the arrival of a message during the execution

of a base service. Each event is characterized by

an event name, which is unique inside the base

service. Events can be fired by a base service after

one of its actions has been invoked. The events

fired by a base service can trigger the invocation

of an action by another base service.

Since base services have, per se, no knowledge

about the service context (i.e., the composition in

which the reside), a higher layer orchestration is nec-

essary to maintain the overall service logic. This ser-

vice logic layer invokes the actions of the different base

service instances passing the correct parameters in the

given context and handles the events that are fed back

by the base services. Since the event-action pattern

is an asynchronous model, we need a mechanism to

dispatch the events to the correct service session. In

our demonstration system, we have implemented this

function in an event-gateway or session manager as a

front-end of a BPEL engine that maintains session

variables and service logic flow.

Figure 4 represents the service execution archi-

tecture and the deployment function that is described

in the next paragraph. More details about the execu-

tion model can be found in [7].

Deploying a Service CompositionSince the creation of a new service in the service

editor involves working with abstract representations,

we need a mechanism to translate and instantiate this

abstract service representation into the execution

environment. This task is performed by the deploy-

ment manager.

Given the graphical representation of the service

as defined in the service creation environment, it will

execute the following steps:

• Extract the base services to be used through the

service composition process.

• Identify dependencies between the base services

and their interconnection requirements.

• Find, for each base service, an active deployment

instance that has enough resources to fulfill the

SLA requirements for the service.

• If no such instance exists, instantiate the base

service in another suitable execution container.

• Reserve the resource according to SLA require-

ments.

• Provision the base service, adding service-dependent

instantiation information.

• Deploy the BPEL script into the service logic exe-

cution engine.

• Activate the service composition by attaching the

initial event in the event gateway.

After the deployment, each service composition

can act as an independent instance in the service plat-

form and a session can be established. A session will

be created as soon as an initial event is triggered in the

event gateway. Upon the initial event, a new session

object is generated and maintained in the service

orchestration engine. Base services may be shared

between compositions so it is necessary to monitor

the individual usage of resources for single base ser-

vices and the overall load on the compositions.

Nevertheless, the sharing of base services must not

lead to interference between the services; therefore,

service and service state are strictly separated.

This is achieved via a monitoring system that con-

trols resource usage and detects potential overload

situations in advance. In the case of overload on a

base service or an execution container, the deploy-

ment manager will be informed and create a new

instance of a base service with the heaviest load in a

different container. This re-deployment capability pro-

vides a self-optimization of the service execution envi-

ronment.

OPUCE Platform Validation ResultsThe first version of the OPUCE platform prototype

was successfully integrated in October 2007, namely,

version 1 (v1). This alpha prototype, which aims to

validate the OPUCE proof of concept, was periodically

updated through February 2009 (v3), which marked

the end of the funded stage of the project.


The validation results reported in this paper are

those of prototype v1.5, which has been used suc-

cessfully since June 2008 for public and internal

demonstrations, as well as testing purposes. It is capa-

ble of the complete lifecycle of a service inside the

platform: creation, deployment, sharing and adver-

tising, personalization and adaptation, and finally,

execution. The SCE, SLM, and SEE—the three core

modules driving the service chain—have been imple-

mented and properly integrated along with three

other side components: the service advertiser, which

facilitates intelligent matching and notification/shar-

ing of services; the user information manager, which

stores user profiles in a secure manner to allow a

personalized OPUCE experience; and the Web portal

for accessing the platform.

While not an integral part of the OPUCE platform,

a set of base services has also been developed for test-

ing purposes, offering IT features (Really Simple

Syndication [RSS] feed reading, Gmail* monitoring)

as well as telco capabilities (SMS, call control, and

text-to-speech). With this set of base services, com-

positions such as the one shown in Figure 2 have

been successfully built, deployed, and executed.

In order to validate OPUCE project results from a

user’s perspective, human factors experts have been

involved from the outset. Use case scenarios and veri-

fication processes have been carried out by experts

Figure 4.Service execution architecture.

BSwidget

Protocoladaptor

Protocoladaptor

WS RA

Lifecyclemanager

Deployment

Provisioning

Event gateway Service logic engine (BPEL)

Base service

Base service

JSLEE AS J2EE† AS

Base service

Base service

Service logicscripts

notifyEvent()

invokeAction()

DeployServiceLogic()

Deploy baseservice

Deploywidget

Provisionbaseservice

Deploy baseservice

Provisionbaseservice

Service mapper

CreateSession()

AS—Application serverBPEL—Business Process Execution LanguageBS—Base serviceJ2EE—Java† Platform, Enterprise Edition

†Trademarks of Sun Microsystems, Inc.

JSLEE—Java Service Logic Execution EnvironmentRA—Resource AdaptorWS—Web service


including psychologists, who also introduced some

perceived value analysis questions. Several standards

and evaluation techniques then identified user inter-

action problems and strengths in order to produce

recommendations.

The goal has been to obtain user feedback under

real OPUCE scenarios, gathering as much user inter-

action data as possible. In the user-centric design phi-

losophy applied in OPUCE, it is crucial to place user

requirements at the forefront. European MultiMedia

Usability Services (EMMUS) specifications [9] and the

International Organization for Standardization (ISO)

9241-11 model [12] have been used to establish a

proper framework.

The results of these quality of experience and

value tests have been both encouraging and enlight-

ening. Encouraging, because the results prove that

the creation paradigm employed in OPUCE is user-

friendly enough to allow non-experts to perform con-

ceptually complicated tasks, and enlightening because

the feedback from quality of experience experts has

revealed the areas in which the user interfaces are

most valuable or should be improved.

Of the test subjects 100 percent without a back-

ground in computer science were able to login to the

platform and start the creation environment, and as

many as 89 percent were able to drag and drop new

base services and configure them without any exter-

nal help. The average perceived ease of use score was

4.78 out of 7 points for the most difficult task: create

and deploy a complete service. Figure 5 shows the

ease of use perceived for several tasks, and demon-

strates that while there is a little frustration in the first

steps, ease of use increases as the user becomes famil-

iarized with the platform.

Suggestions for improvements were mostly related

to user-friendliness and include adding an “undo” but-

ton and help windows in the editors. Both will be

included in future versions of the platform.

Additionally, stress tests have been performed

over the SEE in order to determine how far the

OPUCE platform is from a prototype system that could

be deployed to the general public and handle huge

numbers of users and services. The results have

shown that while the deployment system and Web

service framework are quite robust and work properly

(even if the additional middleware introduces some

latency), the BPEL orchestrator could become a

bottleneck, and become overloaded if the number of

services increases too rapidly.

Different options are currently being explored as

solutions to this problem and will be analyzed for

4.33

3.11

4.11

4.78

1,00

2,00

3,00

4,00

5,00

6,00

7,00

Scenario 1:start to usethe system

Scenario 2:show/hide

actions/events andconnect base services

Scenario 3:configure abase service

Scenario 4:create

a service

Easy

Difficult

Figure 5.Average ease of use perceived for several tasks on a 7-point scale.


possible implementation in OPUCE v3, after consid-

ering the project work plan and resources. The most

basic solutions are based on the substitution of the

current BPEL engine for one that is more robust and

the implementation of a parallelized orchestrator that

can handle multiple BPEL engines at a time. More

complex alternatives aim at a completely distributed

orchestration approach, in which each base service

would be able to determine on its own the next step

in the service composition. Preliminary results show

that this distributed orchestration can function up to

ten times faster.

ConclusionsAs discussed in this paper, the OPUCE platform

integrates all of the required elements to allow user-

driven creation and management of integrated ser-

vices, including Web and communication capabilities. It

includes an intuitive user-friendly graphical interface

that can be used by non-experts to build services, a

lifecycle manager to automate difficult deployment

and maintenance processes, an interface that allows

external providers to introduce their services through

the platform, and a secured execution environment in

which all components are able to interact without

harming the operator’s infrastructure. It is therefore a

solution which is potentially prepared to become

a marketable product in the near future.

OPUCE offers significant advantages to all three

actors in the service delivery chain. First, end users

can use it to build the specific communications appli-

cation they need. Second, it is a means for external

service providers, i.e., small and medium-sized enter-

prises (SMEs), to enter the communications market

without requiring big investments for the deployment

of new infrastructure. And finally, the platform

owner/operator enriches its service portfolio and out-

sources the demanding task of service creation, while

increasing customer satisfaction.

Web mash-up editors such as Yahoo! Pipes or

Microsoft Popfly could be considered competitors for

OPUCE, although it offers several competitive advan-

tages. Most notably, OPUCE is specifically designed to

include communications capabilities, while mash-up

editors are bound to the Web domain and IT services.

Although it seems feasible to integrate mash-up editors

with telco APIs, OPUCE is unique in the sense that it

opens the platform to third parties, while the plat-

form operator maintains control of the sensitive envi-

ronment directly related to network resources and

security. Its event-based execution model specifically

fits the typical asynchronous telco approach, allowing

seamless convergence of both the IT and telco worlds.

OPUCE is designed to support an open service

marketplace that is able to generate revenues for the

platform operator, third parties, and even end users. It

is designed to become a viable market solution, evolv-

ing from the user-generated content era to a user-

generated services one. As a result, the operator will

retain full parity as a key player in the value chain

and cash flows.

In summary, OPUCE is a big step forward toward

the integration of telecommunications and the Web

and provides a powerful tool for telco operators to

compete effectively in the evolving Internet services

market.

AcknowledgementsThe work presented in this paper is executed as

part of the OPUCE project and is partly funded by the

European Union under contract IST-034101. OPUCE

is an Integrated Project of the Sixth Framework

Programme, Priority IST.

*TrademarksApple and iPhone are trademarks of Apple, Inc.Gmail and Google are trademarks of Google Inc.J2EE, JAIN, and Java are trademarks of Sun Microsystems,

Inc.Lego is a trademark of Lego Juris A/S Corporation.Open Mobile Alliance is a trademark of Open Mobile

Alliance Ltd.Popfly is a trademark of Microsoft Corporation.Yahoo! is a registered trademark of Yahoo! Inc.YouTube is a trademark of Google, Inc.

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(Manuscript approved December 2008)

JÜRGEN SIENEL is a research project leader in theservice infrastructure domain at Bell Labsin Stuttgart, Germany. He holds a Diplom-Informatiker degree in computer sciencefrom the University of Stuttgart. Hiscurrent work is focused on service-

oriented computing in telecommunication environmentsincluding IMS enhancements and peer-to-peer systems.Past work also covers different areas in man-machineinterface technologies and multimodal interactionwhere he has contributed to W3C standardization. He iswork-package manager for service lifecycle managementin OPUCE and has been appointed a distinguishedmember of the Alcatel-Lucent Technical Academy.

ALBERTO LEÓN MARTÍN is innovation projects managerof the New Services over Next-GenerationNetworks Division at Telefónica I�D,functioning as a key internationalinnovation expert and businessdevelopment contributor. Previously, he

worked in Latin America and Europe within TelefónicaGroup business units as a technical leader of TelefónicaIP network deployments.

CARLOS BALADRÓN ZORITA serves as the technicalmanager of IST OPUCE. He holds a M. Eng.degree in telecommunications engineeringfrom the University of Valladolid, Spain,where he is also a Ph.D. candidate andworks as a researcher. He has been involved

in several Spanish national and European projects,including IST FP6 satellite-based communicationssystems within IPv6 (SATSIX), covering topics such assatellite communications, voice encoding, next-generation networks (NGNs), VoIP, quality of service(QoS) over NGN, service engineering, and service-oriented architecture (SOA) systems.


LAURENT-WALTER GOIX is a senior research engineerat Telecom Italia Labs, Torino, Italy. Hegraduated in telecommunicationengineering at the National Institute ofApplied Sciences (INSA) Lyon, France andreceived a master’s in telecommunications

from TILS, Italy. His research experience centers on VoIPand next-generation network (NGN) service platforms,focusing on service creation, management, anddelivery. He currently leads a team on context-awareness, Social Web 2.0, and converging NGN/ITmobile services. He is scientific manager of IST OPUCE.

ÁLVARO MARTÍNEZ REOL is an R&D engineer atTelefónica I�D. His research has spannedthe areas of services, software engineering,IP and next-generation networks (NGN),Web and Voice over IP pre-commercialservices, applications, platforms and

terminals, and applied research and development forthe Telefonica Group. Currently, he works in openresearch and collaborative European innovationprojects, targeting residential, SMEs, and communitycustomers.

BELÉN CARRO MARTÍNEZ is a telecommunicationsengineer and a professor within theTelecommunications School in theUniversity of Valladolid, Spain. She holdsa Ph.D. in telecommunications. She alsocollaborates with Cedetel, a non-profit

technological center in management and innovativeR&D projects dealing with systems, networks, andservices for the information society. Her research isfocused on broadband access networks and advancedQoS topics. Dr. Carro Martínez has led projectsincluding IST FP5 Conferencing with BroadbandMultimedia over Geostationary Satellites (ICEBERGS),IST FP6 Media Networking (MEDIANET), and severalCooperation for European sustained Leadership inTelecommunications (CELTIC) initiative projects—Multimedia Communication Service (MaCS), Quality ofReal Time Applications End-to-End over HeterogeneousDomains (QUAR2), and Integrated MultiserviceArchitectures for next Generation Services (IMAGES).She has also managed other R&D projects related tobroadband access network performance and services,including Spanish national research projects incollaboration with major telecommunicationscompanies. ◆

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OPUCE: A telco-driven service mash-up approach