the challenge of networked enterprises for cloud computing interoperability

Computers in Industry xxx (2014) xxx–xxx

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COMIND-2557; No. of Pages 18

The challenge of networked enterprises for cloud computinginteroperability

Istvan Mezgar a,b,*, Ursula Rauschecker c,1

a CIM Research Laboratory, Computer and Automation Research Institute, Hungarian Academy of Sciences, Kende u. 13-17, Budapest 1111, Hungaryb Department of Manufacturing Science and Engineering, Budapest University of Tecnology and Economics, Hungaryc Fraunhofer Institute for Manufacturing Engineering and Automation (Fraunhofer IPA) Department Ultraclean Technology and Micromanufacturing,

Nobelstrasse 12, D-70569 Stuttgart, Germany

A R T I C L E I N F O

Article history:

Received 5 June 2013

Received in revised form 27 January 2014

Accepted 28 January 2014

Available online xxx

Keywords:

Cloud computing

Networked enterprise

Interoperability

Manufacturing

Standardization

A B S T R A C T

Manufacturing enterprises have to organize themselves into effective system architectures forming

different types of Networked Enterprises (NE) to match fast changing market demands. Cloud

Computing (CC) is an important up to date computing concept for NE, as it offers significant financial and

technical advantages beside high-level collaboration possibilities. As cloud computing is a new concept

the solutions for handling interoperability, portability, security, privacy and standardization challenges

have not been solved fully yet. The paper introduces the main characteristics of future Internet-based

enterprises and the different CC models. An overview is given on interoperability and actual

standardization issues in CC environments. A taxonomy on possible connecting forms of networked

enterprises and cloud-based IT systems with reference on interoperability is introduced, parallel

presenting four use cases as well. Finally, an example of connecting cloud and NE is presented as an

effective application of cloud computing in manufacturing industry.

� 2014 Elsevier B.V. All rights reserved.

Contents lists available at ScienceDirect

Computers in Industry

jo ur n al ho m epag e: ww w.els evier . c om / lo cat e/co mp in d

1. Introduction

Based on the results of the information and communicationstechnologies (ICTs), a new ‘‘digital’’ economy is arising. This neweconomy needs a new set of rules and values, which determinethe behaviour of its actors. Participants in the digital marketrealize that traditional attitudes and perspectives in doingbusiness need to be redefined. In this dynamic and turbulentenvironment that requires flexible and fast responses tochanging business needs organizations have to respond byadopting decentralized, team-based, and distributed structuresvariously described in the literature as, e.g. virtual-, networked-,cluster- and resilient virtual organizations/enterprises. Onemain aspect of this approach is that organizations in thisenvironment are networked, i.e. inter-linked on various levelsthrough the use of different networking technologies. The neworganizational architectures need new information and com-munication architectures as well.

* Corresponding author at: CIM Research Laboratory, Computer and Automation

Research Institute, Hungarian Academy of Sciences, Budapest 1111, Kende u. 13-17,

Hungary. Tel.: +36 1 279 6141; fax: +36 14667 503.

E-mail addresses: [email protected] (I. Mezgar),

[email protected] (U. Rauschecker).1 Tel.: +49 711 970 1240; fax: +49 711 970 1010.

Please cite this article in press as: I. Mezgar, U. Rauschecker, Tinteroperability, Comput. Industry (2014), http://dx.doi.org/10.1016

0166-3615/$ – see front matter � 2014 Elsevier B.V. All rights reserved.

http://dx.doi.org/10.1016/j.compind.2014.01.017

The architecture of the organizations is in a recursiveconnection with the IC systems; the IC technology offers newpossibilities for restructuring the organization (and its businessprocesses) itself, in other cases the new demands of a businessprocess force the development of a special IC solution. The finalgoal of all information systems is to provide secure data-,information-, knowledge-, or different services for the users(human beings), and for firms, enterprises.

Today Cloud Computing (CC) is a hot topic, and according toGartner Inc. there are three cloud-related topics (Hybrid Cloud andIT as Service Broker, Cloud/Client Architecture, The Era of PersonalCloud) among the top 10 strategic information technology list for2014 [1]. Because of the very positive market forecasts every mainplayer of the IT sector has already developed its own (different) CCarchitectures, platforms.

Cloud Computing is an important technology for NetworkedEnterprises, as it offers significant financial advantages (pay onlyfor what you use, less in-house IT staff and costs, etc.) whileoffering high-level collaboration possibilities. In spite of theseadvantages the spread of CC in the practice seems to be behind thevery optimistic forecasts. The main disadvantages lay in privacy,security and interoperability problems. The IT community tries tofind the solution for these problems, e.g. with applying differentDeployment Models; for the Networked Enterprises the PrivateCloud – where the CC architecture is owned or leased by one, or bya closed group of enterprises – can be a solution.

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I. Mezgar, U. Rauschecker / Computers in Industry xxx (2014) xxx–xxx2

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According to a survey [2] the biggest contradiction betweenexpectations and results can be seen in operational cost savings, asthe expected savings were 74% and only 41% was achieved. Butorganizations have to cut costs, so if early cloud investments provethat they lower costs, investments in cloud computing willincrease. SMEs are moving to the cloud much quicker, becauseit allows them to get a role in the market above their size.

In cloud computing there is very fast evolution in every fieldbecause of the huge advantages offered for the enterprises.Interoperability, portability problems have to be solved in a shorttime (together with security/privacy) because these elements arethe negative factors of the applications. The paper can give only asnapshot on the actual status of the standardization activities andresults as many different organizations and groups are workinghard in this field and their results can modify the situationintroduced in this paper within a short time.

The paper introduces the main characteristics of NE and thedifferent CC models, pointing out why CC can be an excellentsolution for NE. The advantages and disadvantages of cloudcomputing are listed as well giving special focus on interoperabili-ty challenges. An overview is given on the interoperability andstandardization issues of CC and a taxonomy is introduced onpossible connection forms of networked enterprise architecturesand cloud deployment models. Finally an example is presentedbriefly to show the application possibilities of cloud computing inproduction environment, in the manufacturing industry.

2. Challenges of networked enterprises for cloud computing

2.1. Main characteristics of networked enterprises

In order to fulfil the market demands the flexible, effectivemanufacturing system architectures become more and morepopular around the world. Manufacturing enterprises have ageographically distributed nature, so computer networks forproduction management is an important feature of their operation.There are different approaches, different names that basicallycover the same idea; a flexible network of co-operating autono-mous manufacturing units. Enterprise architectures of this kindare, e.g. the collaborative enterprise, digital enterprise, smartorganization, extended enterprise, virtual enterprise.

Main characteristic of theses architectures is that organizationsin this environment are networked, i.e. inter-linked on variouslevels through the use of different networking technologies.Besides the Internet new (or pilot phase) solutions are offered;wireless networks (Wi-Fi and mobile), powerline communication(using the electric power grid), the Grid technology and lately thecloud computing.

The main characteristics of the digital economy for marketparticipants are as follows:

� networking and horizontal communication, including the smartproduct,� networked environment,� knowledge-based technologies,� simplification and coordination of structure,� customer focus and real-time, ubiquitous responsiveness to

technical and market trends (what customers want, anytime,anywhere),� flexibility, adaptability, agility, mobility,� organizational extendibility, virtuality,� shared values, trust, confidence, transparency and integrity,� ability to operate globally co-operating with local cultures.

In this turbulent environment only those organizations cansurvive which effectively apply the resultsof the differentdisciplines.


2.2. Collaboration in networked enterprises

The collaboration and cooperation are main characteristics ofnetworked enterprises, so the contacts among the users, the humanbeings have outstanding importance. A very important element ofthis human contact is trust. In a networked organization, trust is theatmosphere, the medium in which actors are moving. Trust is thebase of cooperation, the normal behaviour of the human being inthe society. As the rate of cooperation is increasing in all fields of life,the importance of trust is evolving even faster.

Himmelman developed a hierarchy of partnerships [3]. Thelevels of this hierarchy are distinguished from each other by theamount of trust, time, and risk needed to establish and maintainthe partnership. In Himmelman’s framework, networking, coordi-nating, cooperating, and collaborating mean different concepts andare built on each other. Collaboration means exchanging informa-tion, altering activities, sharing resources, and enhancing the

capacity of another individual or organization for mutual benefitand to achieve a common purpose.

A new approach, the collaborative network paradigm has beendeveloped and described in [4] that covers the main characteristicof all different networked units providing a framework to describethese organizations. A collaborative network (CN) is a networkconsisting of different entities (e.g. organization units and humans)that are autonomous, geographically distributed, and heteroge-neous considering their operating goals, environment, socialcapital and culture. The collaboration is supported by computernetwork and makes possible to achieve common or compatiblegoals easier, thus generating joint value.

Most forms of collaborative networks can be connected to anorganization that covers the activities of its units, giving rules forthe participants. These organizations can be called as collaborativenetworked organizations (CNOs). The key concept related to CNOsis described in [5] parallel providing a high level classification ofcollaborative networks, and introducing some application cases inthe manufacturing industry.

The virtual enterprise (VE) has a dynamic and least of all stablenature in the CNOs. In a VE capabilities and competencies comingfrom different enterprises are put together but no node in thenetwork plays a central role. This is a temporary association ofexisting or newly created business entities offered by severalcompanies to form a new agile business entity to satisfy a one-offmarket need. The communication and collaboration is on highestlevel in VEs, so the need for interoperability, portability andsecurity is the highest in these organizational architectures.

2.3. Trends in networked enterprises

Forecasts and reports on the future of manufacturing and theconnected organizations (factories, enterprises) are regularlypublished by different institutes, committees to appoint theresearch directions, themes in this field. The Industrial AdvisoryGroup working for Unit G2 issued a report with the title ‘‘Factoriesof the Future PPP – Strategic Multi-annual Roadmap’’ [6].

In this study it has been stated that the successful developmentof high added value technology should consider the followingstrategic sub-domains:

� sustainable manufacturing;� ICT-enabled intelligent manufacturing;� high performance manufacturing;� exploiting new materials through manufacturing.

The further integration of any newly developed ICT into theproduction and the industrial environments requires complemen-tary research and innovation efforts. These integration aspects will



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play a key role for generating and using smart production systemsfor factories in different industrial sectors. According to the studyICT is a key enabler for improving manufacturing systems at threelevels:

� agile manufacturing and customization involving processautomation control, planning, simulation and optimizationtechnologies, robotics (smart factories);� value creation from global networked operations involving

global supply chain management, product–service connectionand management of distributed manufacturing units (virtualfactories);� better understanding and design of production and manufactur-

ing systems for better product life cycle management involvingsimulation, modelling and knowledge management from theproduct conception level down to manufacturing (digitalfactories).

The main research areas related to ICT-enabled intelligentmanufacturing should include in the virtual factories: ‘‘Product/service systems: Supporting the manufacturing industry in itstransition towards providing customer value via product-linkedservices and solutions based on integrated product/servicesystems and the co-creation of value’’.

The European Technology Platform Manufuture aims topropose, develop and implement a strategy based on Researchand Innovation. A fundamental concept of the Manufuture vision isthat of ‘innovating production’, which embraces new businessmodels, new modes of ‘manufacturing engineering’ and an abilityto profit from ground-breaking manufacturing sciences andtechnologies. The ‘virtual factory’ of the future will manufacturein adaptable networks linking medium- and large-sized OEMs(original equipment manufacturers) with value-chain partners andsuppliers of factory equipment/services selected according toneeds at a given time. Its composition will not be limited by thepresumption of physical co-location, nor by a need to maintainrigid long-term relationships. [7].

According to the position paper ‘‘Vision: Future Internet basedEnterprise Systems 2025’’ [8] the Future Internet will enableenterprises to interact with other entities within (intra) andoutside (inter) the enterprises (e.g. suppliers, business partners,employees, workers, customers) in a seamless way. Interoperabili-ty that is basic factor of data exchange must be extended fromtechniques and tools to all enterprise ICT systems. CloudComputing Interoperability is a must for effective cooperation ofdifferent Internet resources.

It can be stated that according to the trends in futureenterprises collaboration, agility, security, privacy and interopera-bility aspects will play a key role.

3. Main characteristics of cloud computing

3.1. Definitions of cloud computing

There are three similar computing architectures that can beapplied well in networked enterprises. These are the clusters, grids,and clouds. Various definitions and interpretations of ‘‘clouds’’and/or ‘‘cloud computing’’ exist; two of them are introduced in thefollowings.

According to [9] ‘‘A Cloud is a type of parallel and distributedsystem consisting of a collection of inter-connected andvirtualized computers that are dynamically provisioned andpresented as one or more unified computing resource(s) based onservice-level agreements established through negotiation be-tween the service provider and consumers.’’ At a first glance,clouds appear to be a combination of clusters and grids, but it is


not true. Clouds are next-generation data centres with nodes‘‘virtualized’’ through hypervisor technologies such as VirtualMachines (VM). The Virtual Machine is a file (typically called animage) that, when executed, looks to the user like an actual,physical machine. Infrastructure as a Service is often provided asa VM image that can be started or stopped as needed. Changesmade to the VM while it is running can be stored to disc to makethem persistent.

Mell and Grance from NIST (National Institute of Standardiza-tion and Technologies) gave the following definition [10]: ‘‘Cloudcomputing is a model for enabling convenient, on-demandnetwork access to a shared pool of configurable computingresources (e.g. networks, servers, storage, applications, andservices) that can be rapidly provisioned and released withminimal management effort or service provider interaction’’. Theessential characteristics of cloud computing are:

On-demand, self-service. A consumer can automatically accesscomputing resources, (server time, storage and network)according its need.Broad network access. Resources can be available over thenetwork through standard mechanisms by different clientplatforms (e.g. PDAs, mobile phones, and laptops.).Resource pooling. The computing resources of the provider arepooled to serve multiple consumers using a multi-tenantmodel, with different physical and virtual resources dynami-cally assigned and reassigned according to consumer demand.Rapid elasticity. Capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale outand rapidly released to quickly scale in.Measured Service. Cloud systems automatically control, opti-mize monitor, control, and report resource usage (storage,processing, bandwidth, and active user accounts, etc.) providingtransparency for both the provider and consumer of the utilizedservice.

3.2. Cloud models

Cloud computing, includes many aspects of computing (fromhardware to software) so a single solution is not able to provide itall. Clouds can be described by models when their service anddeployment characteristics are introduced, they can be classifiedinto three service models, and into five deployment models.

By leveraging different types of services provided by cloudcomputing, it is useful to satisfy the needs of different user types.Service Models can be classified into the following groups:

� Cloud Software as a Service (SaaS). This type of clouds is calledalso as Service or Application Clouds. The user simply uses thecloud infrastructure or platform, does not manage or control anypart of the cloud infrastructure.� Cloud Platform as a Service (PaaS). The capacity provided to the

user is to deploy onto the cloud infrastructure. The consumer hascontrol only over the deployed applications and possiblyapplication hosting environment configurations.� Cloud Infrastructure as a Service (IaaS). Called also as Resource

Clouds. The cloud provides for the consumer provision proces-sing, storage, networks, and other fundamental computingresources via a service interface. The consumer does not manageor control the cloud infrastructure but has control over operatingsystems, storage, deployed applications, and possibly limitedcontrol of select networking components.

Table 1 gives an overview on the service layers, parallel listingthe main activities and some standards belonging to each layer. Itintroduces also the controlling hierarchy of the different service



Table 1Layers of cloud architecture with activities and standards.


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models connected to the service provider and the consumersmarking the different layers and sub-layers by different graphicalpatterns.

Clouds may be hosted and employed in different styles,depending on the use case, respectively the business model ofthe provider. Deployment Models are the followings:

� Private cloud. The cloud infrastructure is used typically only byone organization (internal cloud).� Community cloud. The cloud infrastructure is shared by several

organizations and supports a specific community that has sharedconcerns (e.g. mission, security requirements, policy, andcompliance considerations).� Public cloud. The cloud infrastructure is made available to the

general public or a large industry group and is owned by anorganization selling cloud services.� Hybrid cloud. The cloud infrastructure is a composition of two or

more clouds (private, community, or public) that remain uniqueentities but are bound together by standardized or proprietarytechnology that enables data and application portability.


� Special purpose clouds. Special purpose clouds are just extensionsof ‘‘normal’’ cloud systems to provide additional, dedicatedcapabilities.

3.3. Advantages of cloud computing

Cloud computing has important characteristics that will bring itto the most important IC technologies. In the followings theadvantages/disadvantages will be mentioned only in a few fields.The main benefits of this approach are that the users of services donot need to own and manage the capital equipment involved. Fromfinancial aspect cloud computing represents a pay-per-usebusiness model and this is the biggest advantage for an averageuser, customer.

General advantages of cloud computing are the massive scale,the homogeneity, the virtualization, resilient computing, low costsoftware, geographical distribution, service orientation andadvanced central security technologies. Security advantages arethat shifting public data to an external cloud reduces the exposureof the internal sensitive data, cloud homogeneity makes security




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auditing/testing simpler, clouds enable automated security man-agement and redundancy/disaster recovery are simpler.

Advantages in data storage are the automated replication, thedata fragmentation and dispersal, provision of data zones (e.g. bycountry), encryption in storage/in transfer and automated dataretention.

3.4. Problems in cloud computing

3.4.1. Security and privacy problems

The most serious drawbacks of cloud are the security issues ofthe identity of users and the security of data. By the very natureof cloud computing, the data belonging to the organization usinga cloud service will be held in a shared environment. A sharedenvironment is implicitly less secure than a non-shared one.Furthermore delegating the storage and processing of data doesnot relieve the organization of its legal and regulatory obliga-tions around this data. Critical points are among others trustingvendor’s security model, customer inability to respond to auditfindings, indirect administrator accountability, and proprietaryimplementations cannot be examined and loss of physicalcontrol.

Strongly related to these issues concerning legislation and datadistribution is the concern of data protection and other potentialsecurity holes arising from the fact that the resources are sharedbetween multiple tenants and the location of the resources beingpotentially unknown. In particular sensitive data or protectedapplications are critical for outsourcing issues. Whilst the datashould be protected in a form that addresses legislative issues withrespect to data location, it should at the same still be manageableby the system.

Because of the many applications of cloud systems and thevariety of cloud types imply different security models andrequirements by the user. As such, classical authentication modelsmay be insufficient. In particular in cases of aggregation and resaleof cloud systems, the mix of security mechanisms may not onlylead to problems of compatibility, but may also lead to the userdistrusting the model due to lack of insight.

3.4.2. Data storage problems

The main problems in the field of data storage are the isolationmanagement/multi-tenancy, the storage controller, single point offailure, exposure of data to third parties.

3.4.3. Interoperability and standardization

Interoperability and standardization have huge impact on thecloud adoption and usage. Standardization will increase andaccelerate the adoption of cloud computing as users will have awider range of choices in cloud without vendor lock-in, portabilityand ability to use the cloud services provided by multiple vendors.This will also include the ability to use an organization’s ownexisting data centre resources seamlessly.

Every new cloud service provider have their own way on how auser or cloud application interacts with their cloud leading to cloudAPI propagation. There is a need for complex developed businessapplications on the clouds to be interoperable. Cloud adoption willbe hampered if there is not a good way of integrating data andapplications across clouds.

According to certain experts interoperability is a biggerproblem than security. ‘‘The greatest challenge facing longer termadoption of cloud computing services is not security, but rathercloud interoperability and data portability’’ say cloud computingexperts from IEEE [11] ‘‘The lack of integration between thesenetworks makes it difficult for organizations to consolidate their ITsystems in the cloud and realize productivity gains and costsavings. To overcome this challenge, industry standards must be


developed to help cloud service providers design interoperableplatforms and enable data portability.’’

3.5. Trends in cloud computing R+D

Cloud computing will play a major role in tomorrow’s economy,creating new jobs and growth. It has to be ensured that there willbe sufficient supply of cloud computing facilities and services sothat companies of all sizes, government institutions and indivi-duals as well can use these to develop innovative services. Cloudsystems must be compatible with the region/country legal system(e.g. in the area of data protection) and technically secure. It shouldalso make extensive use of standards and other means to ensureinteroperability so that all potential users can take full advantageof cloud computing.

Many reports, white papers and other different materials areavailable on cloud trends, research directions, but the forecastedfields cover each other pretty well. According to [12] as an examplethe following fields will be in focus.

Technical research topics to be addressed are:

� elastic scalability;� cloud (systems) development and management;� data management;� programming models and resource control;� trust, security and privacy;� interoperability and standardization.

Non-technical specific issues are:

� economic aspects;� legal issues;� green IT.

4. Interoperability and standardization in cloud systems

4.1. Interoperability in networked enterprises

Interoperability is the ability of two or more systems orapplications to exchange information and to mutually use theinformation that has been exchanged without special effort on thepart of the customer. Interoperability is realized by the implemen-tation of standards (ETSI SR 002 761). In the context of networkedenterprises, interoperability refers to the ability of interactions(exchange of information and services) between enterprisesystems.

Interoperations can take place on different levels in theenterprise. In the ATHENA EU project four layers of interoperabilityconcerns have been defined that can be applied also for networkedenterprises, virtual organizations [13]. In Table 2, these layers areextended with the activities and the applicable standards on eachlevel.

There are different approaches how to solve the interoperabilityproblem in enterprises:

� Integrated approach. There is a common format for all models.This format must be agreed by all parties to elaborate models andbuild systems.� Unified approach. The common format exists at meta-level and

provides a means for semantic equivalence to allow mappingbetween models.� Federated approach. No common format exists. Partners have

to solve interoperability prompt, real-time that means theyhave to share an ontology to map their concepts at the semanticlevel.



Table 2Layers of virtual enterprises for interoperability with activities and standards.

VE Layers Description of functions, activities Standards

Business Collaborative modelling, semantic interoperability, company culture KIF, KQML, UEML 1.0

Process Cross organizational business process, in NEs integrate different internal processes

into a common one

PSL, UEML 1.0

Service, application Flexible execution and service composition, identifying, composing and making

various application functions together

UEML 1.0, APIs, STEP, EDI,

HTML, XML, or eb-XML, J2EE, Java, .NET

Data Information interoperability – to make query languages and different data models

working together

UEML 1.0, XML, flat files, DB


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The detailed description of the methods can be found in [14].The trend and the issues for enterprise integration and interoper-ability in manufacturing systems are presented in detail in [15,16].

4.2. Interoperability and portability in cloud systems

Potential customers (users) identified the huge advantages ofcloud computing, so they have a strong interest in moving to thecloud. Adoption of cloud computing depends greatly on how thecloud can match concerns of the users on interoperability,portability and security. Security is one of the most importantaspects but it is out of the focus of this paper.

In cloud systems there are different demands that can beconnected to interoperability. Portability and data migration havealso emphasized importance in cloud environments.

� Interoperability is concerned with the ability of systems tocommunicate. It requires that the communicated information isunderstood by the receiving system. In the world of cloudcomputing, this means the ability to write code that works withmore than one cloud provider simultaneously, regardless of thedifferences between the providers, so users are concerned aboutthe capability to communicate between or among multipleclouds.� Portability is the ability to run components or systems written

for one environment in another environment. In cloud comput-ing, this includes software and hardware environments (bothphysical and virtual). In this case customers are interested toknow whether they can move their data or applications acrossmultiple cloud environments at low cost and minimal disrup-tion.� Data Migration means the periodic transfer of data from one

hardware or software configuration to another or from onegeneration of computer technology to a subsequent generation.Migration is a necessary action for retaining the integrity of thedata and for allowing users to search, retrieve, and make use ofdata in the face of constantly changing technology.

Cloud providers have to develop mechanisms to support:

� Data portability – the ability of cloud consumers to copy dataobjects into or out of a cloud or to use a disc for bulk data transfer.� System portability – allows the migration of a fully stopped

virtual machine instance or a machine image from one providerto another provider, or migrate applications and services andtheir contents from one service provider to another.� Service interoperability – the ability of cloud consumers to use

their data and services across multiple cloud providers with aunified management interface.

It is important to mention that various cloud service models(SaaS, PaaS, IaaS) may have different requirements in relation toportability and interoperability.


Interoperability can be divided into two main groups in cloud-based systems/applications:

� the interoperability of the cloud systems itself (cloud layer);� the interoperability of the applications (application layer –

industry specific, HW/SW specific).

4.3. Standardization in cloud environments

Standards are the implementation of the technical require-ments of a given ICT field/topic. The fields of standardization can be– e.g. security, portability and interoperability but in this paperonly the latter two are in the focus in spite of the importance ofsecurity.

There are two main aspects mentioned here that have to betaken into consideration when develop standards for cloudcomputing:

� There are a many standards from the fields of, e.g.networking, shared IT systems that can be applied also in cloudcomputing.� All users intends to use the data information stored in their ‘‘old’’

systems.

These two aspects define the technology of standardizationactivities for cloud-based systems. Today it is a problem todetermine exactly where cloud-interoperability standards areneeded. Taking into consideration the great number of the existingstandards that could be applied in clouds, the diverse requirementsof the different system/firms and the very strong demands of thecompanies for immediate launching new cloud standards. It isobvious that the members of the IT community has to join witheach other and forming groups, task forces dealing with thedifferent standardization tasks [17].

Different groups, committees have established a Wiki site forCloud Standards Coordination [18]. The goal of this wiki is todocument the activities of the various SDOs (leading technologyStandards Development Organizations (SDOs)) working on Cloudstandards. Over 10 different (government, professional, university)organizations collaborate to coordinate and communicate stan-dards for Cloud computing and storage.

The working methodology is the following, e.g. in case ofNational Institute of Standards and Technology (NIST). Threecomplementary activities all performed in collaboration with otheragencies and standards development organizations:

1. NIST inserts existing standards and de-facto interfaces asspecifications. – NIST identifies and validates specificationsusing use cases.

2. Organizations contribute open specifications. – NIST receivesand coordinates the prioritization of specifications, and vali-dates using use cases.




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3. NIST identifies gaps in cloud standards (and specifications) andpublishes the gaps on the portal: produces opportunity foroutside organizations to fill them.

Based on the collected materials and documents a ReferenceArchitecture has been developed that helps to define the holes inthe cloud standardization space.

Other groups of professionals, e.g. Cloud Computing Use CaseDiscussion Group (CCUCDG), Distributed Management Task Force(DMTF) also have developed Reference Architectures in coopera-tion focusing other field of cloud standardization. In the followingsections, a short overview of the NIST, CCUCD and DMTFarchitectures are given.

In the frame of most reference architectures, taxonomies forcloud components have been developed as based on the structuredcontexts a better overview can be given on complex systemstructures and their operation. (Taxonomy is the science ofcategorization, or classification, of things based on a predefinedsystem.) As a next step taxonomy can be the base of an ontologythat can provide very flexible, intelligent services, e.g. for a cloudmanagement systems.

4.3.1. NIST cloud computing reference architecture

The NIST cloud computing reference architecture (NCCRA)(Fig. 1) is a tool for describing, discussing, and developing a system-specific architecture using a common framework of reference [19].The objectives of the NIST cloud computing reference architectureare the followings: to illustrate and understand the various cloudservices in the context of an overall cloud computing conceptualmodel; to provide a technical reference to users and otherconsumers to understand, discuss, categorize and compare cloudservices; and to facilitate the analysis of candidate standards forsecurity, interoperability, and portability and reference imple-mentations.

In the following subchapters those components of the referencemodel will be introduced shortly that can be connected tointeroperability and portability standardization issues.

Fig. 1. The NIST conceptual


4.3.1.1. Actors in the cloud. Dataflow communication goes onamong the actors through the cloud carrier:

Cloud consumer – A person or organization that has abusiness connection with, and uses services from the CloudProviders.Cloud provider – A person, organization, or entity responsible forproviding a service available for interested parties.Cloud auditor – A party that can conduct independentassessment of cloud services, information system operations,performance and security of the cloud implementation.Cloud broker – An entity that manages the use, performance anddelivery of cloud services, and negotiates relationships betweenCloud Providers and Cloud Consumers.Cloud carrier – An intermediary that provides connectivity andtransport of cloud services from Cloud Providers to CloudConsumers.

In the followings the roles, activities of cloud consumer, cloudprovider and the cloud carrier will be in the focus.

4.3.1.2. Service orchestration layers. These layers are the base of thecommunication between the Cloud Provider and the CloudCustomer, how the services are working in the cloud.

Service Orchestration refers to the composition of systemcomponents to support the Cloud Providers activities in arrange-ment, coordination and management of computing resources inorder to provide cloud services to Cloud Consumers.

� Service layer – Cloud Providers define interfaces for CloudConsumers to access the computing services in this layer. Accessinterfaces of each of the three service models are provided in thislayer. The optional dependency relationships among SaaS, PaaS,and IaaS components are graphically given as componentsstacking on each other.� Resource abstraction and control layer – This layer contains the

system components that Cloud Providers use to provide and

reference model [19].




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manage access to the physical computing resources throughsoftware abstraction. Examples of resource abstraction compo-nents include software elements such as hypervisors, virtualmachines, virtual data storage, and other computing resourceabstractions. Besides virtual machine technology, other meansfor providing the necessary software abstractions are alsopossible. The control aspect of this layer refers to the softwarecomponents that are responsible for resource allocation, accesscontrol, and usage monitoring.� Physical resource layer – This layer includes all the physical

computing resource elements (e.g. computers (CPU and memo-ry), all networks HW elements, storage components) and otherphysical computing infrastructure elements.

4.3.1.3. Cloud service management. Cloud service managementincludes all of the service-related functions that are necessaryfor the management and operation of those services required by orproposed to cloud consumers. Cloud service management can bedescribed from the perspective of business support, provisioningand configuration, and from the perspective of portability andinteroperability requirements.

4.3.1.4. Taxonomy based on NCCRA. A four-level taxonomy hasbeen developed to describe the key concepts about cloudcomputing based on the NIST cloud computing referencearchitecture. A short summary of the levels is as follows:

� Level 1: Role, which indicates a set of obligations and behavioursas conceptualized by the associated actors in the context of cloudcomputing.� Level 2: Activity, which entails the general behaviours or tasks

associated to a specific role.� Level 3: Component, which refer to the specific processes,

actions, or tasks that must be performed to meet the objective ofa specific activity.� Level 4: Sub-component, which present a modular part of a

component.

A vocabulary with cloud taxonomy terms and definitions canalso be found in the publication.

Fig. 2. The CCUCDG taxonomy


4.3.2. DMTF cloud reference architecture and life cycle model

The DMTF architecture together with the associated service lifecycle and interoperability concepts forms a whole [20]. The work ofthe DMTF is of special interest because it has a clear focus on thelife cycle of Cloud Services and provides a comprehensive set ofrelated use cases together with detailed formal specifications ofprovider interfaces. The life cycle definition of cloud services is theessence of the DMTF White Papers.

The proper definition of the lifecycle of cloud services allows theidentification of exemplary functional interfaces that cloudconsumers need to establish with the cloud service provider.The cloud service reference architecture describes key entitiessuch as actors, interfaces, data artefacts, and profiles with anindication of interrelationships among them. The following stagesare defined within the lifecycle:

1. Template. A developer defines the service in a template thatdescribes the content of and interfaces to a service.

2. Offering. A provider applies constraints, costs, and policies to atemplate to create an offering available for request by a consumer.

3. Contract. A consumer and provider enter into a contract forservices, including agreements on costs, SLAs, SLOs, and specificconfiguration options.

4. Provision service. A provider deploys (or modifies) a serviceinstance per the contract with the consumer.

5. Runtime maintenance. A provider manages a deployed serviceand all its resources, including monitoring resources andnotifying the consumer of key situations.

6. End of service. A provider halts a service instance, includingreclaiming resources for redeployment to support other service

4.3.3. Taxonomy for cloud computing – CCUCDG

Comparable to the DMTF reference architecture the CCUCDGintroduces a so-called Cloud Taxonomy as shown in Fig. 2 [21]. Inthis figure, service consumers use the services provided throughthe cloud, service providers manage the cloud infrastructure, andservice developers create the services themselves.

From this Cloud Taxonomy the paper derives a StandardsTaxonomy that can be used to categorize Cloud related standardsand to identify different types of reference points.

for cloud computing [21].




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The different types of standards indicate several interoperabili-ty issues:

� Across Cloud Service Types: As cloud applications can usedifferent types of cloud services (SaaS, PaaS, IaaS) standards todefine how these different services can work together.� Within Cloud Service Types: Within each type of cloud service

(IaaS, PaaS or SaaS), open standards make it possible to avoidvendor lock-in.

* In case of IaaS Common APIs for other cloud infrastructureservices such as storage, message queues could provide similarbenefits, as common formats for data and data interchange. Inthe case of virtual machines, a common virtual machine formatis crucial.

* For Platform as a Service, most of the platforms in the cloud areapplication frameworks. Those frameworks typically providecommon services such as user interfaces, storage anddatabases, but they are accessible only through the APIs ofthe framework.

* For Software as a Service, open standards are applied at theapplication level. Most of the standards work here are non-cloud-specific. E.g. a word processing application running onthe cloud should support standards for document portability;not taking into consideration whether the application isrunning in the cloud.� Between the Cloud and the Enterprise: The standards that can

define how an enterprise application can communicate withcloud resources such (e.g. a database) would make possible thatapplication to use cloud services directly, without modifica-tions. Standards that can integrate cloud computing withexisting architectures and applications belong to the ‘‘mostwanted’’ category of developers.� Within an Enterprise: The standards within an enterprise are

determined by the interoperability demands of the usedapplications and the standards that are applied between theenterprises and the cloud also have to take into consideration.

4.3.4. Existing standards for cloud computing

The interfaces that are offered for cloud users can be groupedinto two major categories, with interoperability determinedseparately for each service category. The interface that is presentedto (or by) the contents of the cloud encompasses the primaryfunction of the cloud service. This is distinct from the interface thatis used to manage the use of the cloud service. The cloud usercontrols the use of the cloud services through the ManagementInterface (starting, stopping, and manipulating virtual machineimages and associated resources) [22].

4.3.4.1. Standards for interoperability. The interoperability of cloudservices can be categorized by the management and functionalinterfaces of the cloud services. Many existing IT standardscontribute to the interoperability between cloud consumerapplications and cloud service, and between cloud servicesthemselves. There are standardization efforts that are specificallyinitiated to address the interoperability issues in the cloud.

� Open Cloud Computing Interface (OCCI); Open Grid Forum.� Cloud Data Management Interface (CDMI); Storage Networking

Industry Association, SNIA.� IEEE P2301 – Draft Guide for Cloud Portability and Interopera-

bility Profiles (CPIP) – for application in portability, management,interoperability interfaces, file formats and operating conven-tions (final version for 2014). – The standard is planned to beapplied by vendors, service providers, and consumers indeveloping, building, and using cloud computing. (http://standards.ieee.org/develop/project/2301.html).


� IEEE P2302 – Draft Standard for Intercloud Interoperability andFederation (SIIF). For access of documents, photos (storage), anddifferent (computing) applications from anywhere by anyequipment (e.g. laptops, tablets, smart-phones) (http://stan-dards.ieee.org/develop/project/2302.html).

4.3.4.2. Standards for portability. Portability issues in the cloudinclude workload and data portability. While some of the cloudworkload portability issues are new, a lot of existing data andmetadata standards have been developed before the cloud era. Inthe followings only the few cloud-specific portability standards arelisted.

* Data portability- Cloud Data Management Interface (CDMI); SNIA. Approved

Standard.* System portability

- Open Virtualization Format (OVF); DMTF.- IEEE P2301, Draft Guide for Cloud Portability and Interopera-

bility Profiles (CPIP), IEEE.

4.3.5. Demands for standards in cloud computing

Based on the collected existing standards and the demands ofthe customers the gap analysis can be done. The extent of thisstudy does not allow presenting the results they can be reach in[22] or at the Wiki site [18].

Mentioning only a few standardization priorities in thefollowings:

� Standards supporting migration in all levels.� Interoperability between existing in-house IT systems and cloud

based systems.

5. A taxonomy of cloud architectures in networked enterprises

5.1. Virtual enterprises and cloud computing

Collaborative network organizations have a very flexibleoperation philosophy based on the continuous change in theirstructure, in the integration of information – and material flowsand in their high level collaboration.

From the different types of networked enterprises the virtualenterprise (VE) has been selected for the analysis as the membersof a VE are changing frequently, its organization structure is highlyflexible. Originating from the frequent organizational changestheir IT systems has to be able to follow the demand of the new VEmembers. This means that new IT systems are involved frequentlyinto the VE, so the interoperability is a continuous challenge for theIT system of a VE.

As cloud computing offers the same flexibility on the field of ITas VE do in the field of organizations it is obvious to analyse theintegration possibilities of the systems based on the twoparadigms. In case of connecting VE and cloud architectures anenhanced focus has to be taken on interoperability issues as thefast changes in the different fields of VEs generates frequent needfor smooth migration, data-, system- and service-portability incloud environments.

As an addition the virtual enterprise can be handled as anapproach for achieving high efficiency in intra- and inter-organizational value/supply chains. Integration of information –and material flow generates transparency in the entire value chainthat raises the operation efficiency in the VE. So, in today’s serviceorientated approaches in information technology based systemsthe connection of VE and cloud computing paradigms has acommanding importance.


http://standards.ieee.org/develop/project/2301.html






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5.2. A taxonomy of cloud-based VE architectures

5.2.1. Background of the taxonomy

Taxonomies are structured descriptions of a given set of objectsor terms taking into consideration all components. Mathematical-ly, taxonomy is a tree structure of classifications for a given set ofobjects, terms. Based on the taxonomy the structure and operationof a complex system can be better understood, the transparency ofthe processes will be on higher level.

The goal of developing the taxonomy was to classify, describethe objects, actors and different components interrelated withinteroperability when connecting virtual enterprises with cloudenvironment (CE). In the taxonomy not all aspects of connectingVEs and clouds have been taken into consideration, only somebasic combinations of VE architectures and different CEs (Fig. 3).The classification has a simplified, practice-oriented structurefocusing on IT or closely IT related issues. A ‘‘perfect’’ taxonomy isalways too complex, not easy to manage, so simplifications makethe taxonomy more transparent. The VE-CE taxonomy is based onand can be considered as an extension of the approach presented in[21] into the direction of connecting virtual enterprises and cloudenvironments. The figures in the Use Case introductions do notcontain structural details but the basic characteristics of thecombined environments can be seen.

In the literature it is not always clear what is the differencebetween enterprise integration (EI) and connection. In the presenttaxonomy the approach detailed in [23] has been applied. Theintegration of (inter- or intra-) enterprise activities is differentfrom enterprise information systems integration. While EI hasstrong organizational, control, technological and managementdimensions, from IT view EI mostly means connecting computersystems and IT applications to support business process opera-tions like distributed business processes, business-to-businessintegration.

The taxonomy is not focusing directly on interoperability but onconnection, operation of connected VE and cloud informationsystems. Interoperability possibilities are embedded into thisenvironment on different levels, in different ways as a vitalelement of the joint operation.

In the previous chapters the main characteristics of both virtualenterprises and cloud computing have been introduced so in thedescription of classes no duplicated detailed introductions havebeen given, only short summaries are written.

Connecting VCloud

Actors in the architecture Cloud Installation Types

Cloud

Virtual Enterprise

Service provider

Customer, user

Cloud Service types

SaaS

PaaS

IaaS

Private

Public

Cloud ininteroper

Applicinteroper

XaaS

Service inter

System po

Data por

Data mig

Hybrid

Community

Broker Special purpose

Fig. 3. Taxonomy of VE and cloud connec


5.2.2. Classes of the taxonomy

This section describes the classes and subclasses on the first andsecond levels of the taxonomy.

The root (Level 0) of the taxonomy refers to the connection of VEand cloud-based systems.

Classes on the first level:Class1 – Actors in the Architecture – The humans, IT systems

and organizations that participates in the activities of theconnected cloud and VE.

Subclasses:

� The cloud system.� The virtual enterprise.� The customers, consumers, users – organization/person who

uses the output of a system.� The service providers – offers services for consumers.� The broker – integrator of an e.g. production network who

manages the network.

Class2 – Cloud Service types – define the services that areavailable on the different levels. The levels are organized into foursub-classes.

Subclasses:

� Software as a Service (SaaS) – collaboration, content anddocument management, business (sales, billing, etc.), ERP, e-mail, social networks, web services, different other servicesprovided by software applications.� Platform as a Service (PaaS) – integration; business intelligence;

general services; develop, test, deploy manage applicationshosted in the cloud environment over the Internet (e.g.virtualized servers and operating systems).� Infrastructure as a Service (IaaS) – access to virtual computers,

service management, platform hosting, network accessiblestorage, hardware, network infrastructure components, funda-mental computing resources� Anything as a Service (XaaS) – the acronym refers to the

increasing number of services that are delivered over theInternet, e.g. Network as a Service (NaaS), Manufacturing as aService (MaaS).

Class3 – Cloud Deployment types – As the term cloudcomputing refers in general to the delivery of services according

E and

Cloud interoperability types and levels

Duration of VE connection

ternal ability

ation ability

Single-project

Temporary

VE interoperability levels

Business

Process

Service, application operability

rtability

tability

ration

Permanent

Data

tion types and their interoperability.



Fig. 4. Main cloud layers controlled by different service models – figures applied in

use case scenarios.

Fig. 5. Layers of interoperability in VE – figure applied in use case scenarios.


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to demand of consumers over a computer network, this classdescribes the possible basic deployment types based on [19].

Subclasses:

� Private – cloud infrastructure is operated only for a singleorganization that has exclusive access to infrastructure andresources (on-site or outsourced).� Public – cloud infrastructure and computing resources are

available for the general public through a public network.� Hybrid – is a composition of two or more clouds they keep their

unique entities but are connected through proprietary orstandardized interfaces/protocols. Data and application porta-bility is possible.� Community – serves a group of organizations that have common

security and privacy considerations.� Special purpose – this type of cloud has special attributes or

combination of them with the conventional ones.

Class4 – Cloud interoperability types and levels – information,data, etc. exchange within or, between different cloud services, ormoving data, services, virtual machine instances from a provider toanother one – all interoperability, portability and migrationactivities belongs to this class.

Subclasses:

� Cloud internal interoperability – interoperability within cloudservice types.� Application interoperability – applications can be moved

between different cloud deployment models, e.g. back and forthbetween private clouds and public clouds. SW tools andstandards are needed that makes possible communicationbetween different cloud vendors and services.� Service interoperability – applications can use different types of

cloud services (XaaS). Working together these services needsproper standards.� System portability – moving applications or service content or

virtual machine instances between providers.� Data portability – the ability to copy data objects into or out of

cloud.� Data migration – periodic data transfer from one HW, SW

configuration to another one.

Class5 – Duration of VE connection – Fast reaction (speed) andflexibility are necessary to meet short-term emerging marketopportunities. VE capacities and capabilities can rapidly transformto adapt to these emerging conditions. The duration of VEoperation depends on the frequency of market changes.

Subclasses:

� Single-project – project-based organization exists only until theproject is concluded and then break up.� Temporary – in unstable conditions the VE may constantly

change its partnership structure to match dominant conditions.� Permanent – under stable conditions the networked VE may

keep the same partners for a considerable time and maintaincloser collaborative relationship with them.

Class6 – VE interoperability levels – Interoperations can takeplace on various levels of a VE. This classification is given from apoint of view of IT based applications (see Table 2).

Subclasses:

� Business – semantic interoperability;� Process – business processes;� Service, applications – application functions;� Data – information interoperability.


In the following subchapter some selected scenarios ofconnecting VE and cloud architectures will be introduced in theform of use cases. The aspects of selection were

� typical combinations from the practice;� representing the manufacturing example in Section 6.

5.3. Use Case scenarios of connecting virtual enterprises and cloud

environments

The following Use Cases are based on the taxonomy introducedin the previous subsections and outline the interoperabilitypossibilities/tools/standards in the given scenario.

The Use Cases intend to illustrate the most typical cloudscenarios in operating virtual enterprises within a cloudenvironment. There are many combinations of connectingdifferent types of VEs to different types of clouds, so in thepresent descriptions only a very little part of them will beintroduced. Figs. 4 and 5 are small-sized qualitative figuresembedded into the cloud and VE symbols of Use Cases showingwhich layers are involved into interoperability operations in thegiven case.

The set of symbols in Fig. 4 represent the main cloud layers(service, resource, and physical resource) in a qualitative waygiving the control range of the different service models (SaaS, PaaS,IaaS) at the same time. One or more of these qualitative figures areinserted into the cloud symbols according to their role in the givenUse Case. Fig. 5 shows the four interoperability levels of VE(business, process, service, and data) in a qualitative way. Byinserting this figure into the VE symbol of the Use Case it makesthese figures more informative as it can give the acting layers in theactual Use Case.



Fig. 6. Use Case I – a permanent virtual enterprise interacts with the end user

(customer) using a community cloud.Fig. 7. Use Case II – VE uses a private cloud for internal resource sharing.


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5.3.1. Use Case I – VE interacts with customer through a community

cloud

In this scenario a virtual enterprise uses an internal communitycloud to provide services and data for the customer (Fig. 6). Whenthe customer interacts with the VE the proper member enterpriseof the VE provides data, service or results for the customer who hasno information which member of the VE has provided the service/data.

The member enterprises are connected to the community cloudinside the VE. This scenario looks a good solution both forindividual enterprises and the VE. In this case the memberenterprises do not need to communicate directly to each other, allinternal data exchange can be done through the community cloud.The outgoing communication from the VE to/from customers alsouses the community cloud. Enterprises and customers need toregister to join to the VE and using the cloud services.

The inserted small-size qualitative figures show that thecommunity cloud can apply in this case SaaS or PaaS servicemodels. The member-enterprises of the VE apply all four VE layersas there are data, service, process flows and collaboration amongthem as their connection is a permanent (marked with P in thefigure), works for a longer period.

Based on the figure it can be defined in preliminary systemconfiguration/selection phase the standards (interoperability) thatwill be needed for smooth operation of the system introduced inUse Case I.

Main characteristics of Use Case I when applying the classes/subclasses of the proposed taxonomy are the following:

� Class1: Actors in the Architecture – customer/user, cloud, virtualenterprises (with members).� Class2: Cloud Service types – service models can be SaaS or PaaS.� Class3: Cloud Deployment type – community cloud� Class4: Cloud interoperability types and levels – application

standards are sector specific in this case.� Class5: Duration of VE connection – the VE is a permanent one as

the community cloud collects a group of enterprises belonging tothe same sector.� Class6: VE interoperability levels – process, service, application,

data.


The VE-CC configuration that will be introduced in Section 6(ManuCloud) belongs to this type of connected VE-cloud environ-ment.

5.3.2. Use Case II – VE using a private cloud for internal resource

sharing

The members (E1; E2) of VE1 are connected to the private cloudthrough intranet (Fig. 7). The enterprises interact with each otherdirectly using proprietary interfaces, industry-specific standardsand common APIs. The member enterprises use the resources ofthe cloud (service, data) according to their actual needs. There is nohigh-level collaboration among the members, so only the data andservice layers of the VE interoperability model are in use (the littleembedded figure shows this). The private cloud can apply in thiscase SaaS or PaaS service models as data and services are providedfor the cloud users.

The VE is a permanent one (e.g. VE1-P). The big advantage ofthis scenario is that security, privacy and management aspects donot need to be severe as the environment is a closed one.

Use Case II can be described with the classes/subclasses of theproposed taxonomy as follows:

� Class1: Actors in the Architecture – virtual enterprises (withmembers), cloud.� Class2: Cloud Service types – SaaS, PaaS.� Class3: Cloud Deployment type – private cloud.� Class4: Cloud interoperability types and levels – not cloud

specific standards, data portability.� Class5: Duration of VE connection – permanent.� Class6: VE interoperability levels – depending on applications.

5.3.3. Use Case III – VEs use the resources of a public cloud

In Fig. 8, a simple architecture is represented. Two VEs areconnected to a public cloud. Resources are hosted in the publiccloud and member organizations of the VEs have access to them.All the three service models can be selected as option in the publiccloud in this type of scenario. The VE can be a temporaryorganization in this case (e.g. VE1-T). In the VE there is only dataand application flow (shown by the embedded figures too).



Fig. 8. Use Case III – VE member enterprises use the resources of the public cloud according to their actual needs.

Fig. 9. Use Case IV – coordinated use of multiple clouds by a VE and its member-

enterprises.


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The interoperability problem is more serious in case of VEs;they are more sensitive for the lack of standards.

Supply chain control is a typical application example in thiscase for networked production environments. The standards forinteroperability can be selected based on the final configurationdecision.

When applying the classes/subclasses of the proposed taxono-my the description of Use Case III looks like the following:

� Class1: Actors in the Architecture – VEs (with members), cloud.� Class2: Cloud Service types – SaaS, PaaS, IaaS.� Class3: Cloud Deployment type – public cloud.� Class4: Cloud interoperability types and levels – depending on

application and cloud service type.� Class5: Duration of VE connection – it can be single-project or

temporary.� Class6: VE interoperability levels – depending on application and

cloud service type.

5.3.4. Use Case IV – coordinated use of multiple clouds by a VE

In this use case (Fig. 9) member enterprises operate theirprivate cloud and these private clouds work together with thecommunity cloud inside the VE. This scenario is a complex one, atpresent it is a theoretical possibility. The private clouds serve theinternal needs of the enterprise (E1, E2) and the private clouds areconnected to a community cloud coordinating the operation of thevirtual enterprise (similar to Use Case I). Interoperability problemscan occur when connecting the different private clouds to thecommunity cloud, and also can be critical handling the manydifferent services in the community cloud.

As a next step the virtual enterprise is connected to a publiccloud. The layered structure provides a very effective access toservices and resources. In the first step the resources of the privatecloud is used by the enterprises then the community cloud comesto operation. In this configuration security and privacy problemshave more emphases besides the big question marks of interoper-ability.

The description of Use Case IV using the classes/subclasses ofthe proposed taxonomy looks like the following:

� Class1: Actors in the Architecture – virtual enterprises (withmembers), clouds.


� Class2: Cloud Service types – can be SaaS, PaaS or IaaS.� Class3: Cloud Deployment types – Private, community and

public.� Class4: Cloud interoperability types and levels – depending on

application and cloud service type.� Class5: Duration of VE connection – permanent (private and

community), temporary (public).� Class6: VE interoperability levels – depending on application and

cloud service type.

It can be seen that the combination of virtual enterprises withcloud computing can result very effective production systemarchitectures in case the proper standards are available. So, theinteroperability problem is more serious in these cases then in caseof a conventional (simple) enterprise.




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Based on the descriptions of the introduced Use Cases it can bestated that with the proposed taxonomy for connected configura-tions of virtual enterprises and cloud environments the use cases(the connected virtual enterprises and cloud environments) can bedescribed correctly.

6. Application of cloud computing in production

6.1. Industrial applications of cloud computing

Manufacturing enterprises both SMEs and larger enterprises aretrying to find the way how to apply cloud technology. Theadvantages (agility, easy configuration/reconfiguration of ITsystem, ‘‘pay-as-you-go’’ model) seem to be really attractive butthe drawbacks are stronger at present. According to industrial ITexperts, e.g. [24] there are two main areas where CC will becomepopular for manufacturing companies:

� inter-factory collaboration (supply chain visibility, transporta-tion management, supplier/contract negotiation),� high performance computing that use digital models to (1)

virtually test the products or manufacturing system, (2)understand the business environment better through businessintelligence and (3) make decisions.

In order to be able to use effectively cloud technology in theabove applications standardization and interoperability solutionshave of vital importance.

Cloud solutions are/will be used most frequently for supplychain visibility, transportation management and supplier/contractnegotiation. Partners can create cloud computing modules toaddress other manufacturing issues, e.g. supply chain execution,shop floor planning, demand planning and production scheduling.

Companies increase the use of digital models to virtually testtheir products or manufacturing system, to understand theirbusiness environment better through business intelligence anddecision making that needs additional, flexibly usable, computingpower. The models are typically highly parallelizable and fit wellfor a cloud environment.

The main risks of cloud computing for the industry are network-(reliability, privacy and security) and SLA (Service Level Agree-ment) related. In SLAs services, responsibilities, warranties,guaranties and priorities are fixed that provide the safe andreliable operation (from legal aspects) for the consumer by theservice provider.

In the followings an on-going project will be introduced brieflyto illustrate the industrial application of cloud computingtechnology.

6.2. Cloud architecture for manufacturing

This section describes how the ideas of this paper match currentindustrial needs and research efforts, especially the challengesdealt with in the ManuCloud project which is funded within FP7 ofthe European Commission [25,26].

6.2.1. Main goals of the project

During the past years, manufacturing has experienced anincreasing need for customer-specific production as well as forfast reaction to rapidly changing market needs. These trends couldbe found throughout many high-tech industry branches, likeautomotive, photovoltaic, semiconductor, and consumer elec-tronics. However, it has to be noticed, that especially in theseindustries products are usually not manufactured within oneproduction site or one company. This means that product changesor product customization not only affects the organization selling


the end-product but also influences at least parts of the relatedsupply chain. Due to this interference, it is necessary thatmanufacturers closely cooperate with their suppliers in orderto exchange information about product specifications and to alignwith each other in terms of delivery dates and other logisticdetails. In some cases, it may even be necessary to choosealternative suppliers whose manufacturing capabilities cover thenewly requested features. Of course, this causes much effort onboth sides and also delays feedback to end-customers when everysupply chain member has to gather feedback from its suppliersbefore.

Obviously, networked enterprise and cloud computingapproaches as described above could be a measure to improvethe work- and information flow throughout such productionnetworks as they support the (semi-) automated integration ofproduction network integration on IT level. Up to now, there arealready solutions available for the exchange of business documentslike orders and invoices [27]. However, the related work flows anddata transfer is restricted to business-related information. What ismissing in order to enable flexible production network setup basedon product and production needs is the integration of productspecifications and manufacturing IT systems to the overall multi-site manufacturing management infrastructure.

There are various emerging concepts of cloud manufacturingwhich are promising to transfer the principles and benefits of cloudcomputing to the manufacturing and supply chain managementdomain [28,29,30]. What all of these approaches have in commonis the idea of distributed manufacturing throughout a networkwhich is managed based on services.

Especially the adaption of this XaaS (Anything-as-a-Service)concept to the production domain which means implementation ofMaaS (Manufacturing-as-a-Service) could help to overcome theissues explained above. However, it has to be considered that thisis still an object to research work due to the complexity whichresults from the various aspects which range from exchange ofproduct specifications and business documents to the alignment ofschedules, to the tracking of products throughout the supply chain,etc.

The primary disadvantages of CC for the industry are the risksassociated with internet reliability, security and access of data(third party), intellectual property rights and the financial stabilityof the service provider.

6.2.2. The cloud architecture

The trend of changing traditional business models to servicebusiness models can be noticed for various industry branches. Oneof the most important reasons for the success of these models is theflexibility which they provide to their users or customers. This isalso why MaaS (Manufacturing-as-a-Service) is regarded as one ofthe most promising approaches in order to increase qualitative andquantitative production network flexibility. For this reason, theManuCloud project focuses on the development of appropriateservice descriptions and a MaaS infrastructure to manage theprovided manufacturing services throughout the network. Accord-ing to computing cloud actors, the following roles have beenidentified for manufacturing clouds matching with the first class‘‘Actors in the Architecture’’ of the taxonomy introduced in Section5.2.2 (Table 3).

In order to illustrate how such an infrastructure works, thefollowing work-flow is described (Fig. 10): Manufacturers(manufacturing service providers) extract manufacturing servicedescriptions from their internal IT systems like ERP (EnterpriseResource Planning) and MES (Manufacturing Execution System),and publish them to a MaaS infrastructure via a so-called CloudConnector. There, the services can be searched, aggregated, andconfigured by supply chain integrators or end-customers. The



Table 3Roles identified in manufacturing cloud.

Actor in manufacturing Cloud actor Description of activities

Infrastructure provider Cloud provider The party who hosts the IT infrastructure for the MaaS environment

Manufacturing service provider Service host Manufacturing service provider (Manufacturing cloud provider): A party which owns

manufacturing facilities and would like to deliver products to a manufacturing cloud. Its motivation

may be to increase or balance production load or to strengthen the market position by providing

additional information and flexibility.

Manufacturing service consumer Cloud consumer A user who wants to purchase a product or sub-product. He may not be able to manufacture the

products by himself due to reasons like cost-effectiveness or know-how leakages

Manufacturing service integrator Cloud broker The integrator of a supply chain or production network who combines manufacturing services in

order to build up an aggregated and interlinked manufacturing service structure which represents

the structure of the respective production network. He manages the production network and adapts

it, based on the options provided by the services, flexibly to current needs and herewith, provides a

more sophisticated manufacturing service to his customers


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configured service instances are sent back to the service providersin order to check their availability by means of up-to-date datafrom internal IT systems, e.g. in terms of costs and due dates. Whenthere are no constraints hurt, an order is to be created andforwarded to each organization that contributes (sub-) services toits fulfilment. In this way the interaction between manufacturingenterprises and end-customers is bi-directional.

6.2.3. Interoperability challenge

In order to be able to execute those workflows in a consistentand integrated way, the following features of the Cloud Connectorhave been identified to be relevant:

� Extraction of manufacturing service descriptions from factory-level IT systems and their publication to the MaaS environment.� Providing feedback about the manufacturability of certain

service requests (e.g. in terms of technology or time).� Receiving orders and forward them to factory-level IT systems

(e.g. after manual confirmation).� Providing information about the current status of production and

further tracking and tracing data (e.g. measurement data to beused for a later production step at another manufacturing site).

In order to achieve these goals, it is not only necessary totransfer messages in a harmonized format that is able to beadapted to all kinds of factories which are to be integrated to theoverall infrastructure. For the extraction of manufacturing servicedescriptions and for receiving concrete orders etc. a standardizedframework and workflow for the integration of the cloud connectorinfrastructure to factory-level IT systems is required. Theseintegration levels of the IT system answer to the descriptiongiven in the taxonomy ‘‘VE interoperability levels’’ class. On thecloud side of the Cloud Connector the subclasses ‘‘ApplicationInteroperability’’ and ‘‘Service Interoperability’’ of ‘‘Cloud Interop-erability Types and levels’’ class are matching the descriptions.

It is also essential to ensure that security and privacy areensured by the MaaS and communication infrastructure. Thisincludes not only the exchange of messages but also a detailedmanagement of access rights which goes beyond role basedconcepts on data level. Furthermore, there is a need forstandardized contracts as long-lasting negotiations would elimi-nate at least partially the benefits from flexible and fast IT-integration.

6.2.4. Applied standards

As the exchange of information among participants in the MaaSinfrastructure requires harmonization and standardization, areview on the state-of-the-art and existing standard wasconducted which had the following results:

From the IT infrastructure point of view, there could existingstandards be reused which support the management of IT


infrastructures and standardized message transfer, such as XML,web services, and IaaS/PaaS concepts (see Table 1 introducingcloud standards).

For the structuring and standardization of information to beexchanged, there are various approaches. On business level, thereare mainly EDI (Electronic Data Interchange)-related standards likeOdette, ebXML, RosettaNet, etc. which are widely applied inindustry for the exchange of business documents like purchaseorders and invoices. However, they do not cover the product andproduction aspect which is needed to enable communication incloud manufacturing. Further approaches like USDL (UnifiedService Description Language) are only focusing on the descriptionof services, their providers, cost models, etc. but here again, theaspect of product and production technology is missing.

Most approaches to describe manufacturing technologiesprovided by manufacturing services are based on ontologies[31,32,33]. The manufacturing service descriptions defined in thatway, however, are in most cases restricted to a certain industrybranch or application such as machining and do not includeproduct-related information which is needed to provide custom-izable manufacturing services. On the other hand, productspecification standards like STEP do in most cases not supportthe involvement of manufacturing information.

For this reason, the ManuCloud project develops an overallmanufacturing service description that combines product andproduction aspects with information about the providing organi-zation, costs, and logistic-related boundary conditions by alsoinvolving, extending, and combining existing standards.

6.2.5. Applied security services

Security is the most important characteristics of cloud systemsparallel with interoperability. Security aspects influence in thebiggest rate the decision makers to invest or not to invest into acloud environment.

There are three main statements on which further securityconsiderations are based:

1. It has to be ensured that no (external) third parties would beable to access the system and execute attacks on it.

2. Data has to be protected against access from unauthorized users.3. Users have to be uniquely identified, authenticated and

authorized when accessing the system.

In order to deal with these challenges and to develop a secureManuCloud IT infrastructure, the following subset of the functionalclasses of cloud computing have been considered:

Identification and authentication, privacy and data protection,confidentiality and integrity, communication (encrypt messages),encryption (database) and interfaces.

As communication between components (and users) appears atvarious points in the ManuCloud inter-factory infrastructure (and



Fig. 10. The MaaS infrastructure and workflow in the ManuCloud.

Table 4The functional layers of the cloud manufacturing platform.

ATHENA layer Cloud connector layer

Business Provision of the overall platform framework including basic

functionalities such as virtual organization and product

management

Process MES and ERP functionalities on cloud level: inter-factory

process planning and scheduling, execution, tracking, etc.

Services Manufacturing services and their management

Data Cloud connector: data extraction and alignment


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also appears periodically), several communication security sce-narios should take place in a standardized way:

� User Registration – during the registration process it is necessaryto uniquely identify a user (organization) and to make sure thathe really belongs to the organization as stated, that the given(personal) information is correct.� Certificates – a unique software certificate is distributed to each

user.� Authentication – authentication of users and organizations will

take place.� Encryption of messages – encryption of messages is based on

certificates.� Exchange of messages – between the ManuCloud infrastructure

components which takes place via the Internet will applystandards.

There are many standards between ERP-systems or in case ofManuCloud project for Intra-Factory communication. Anothergroup of standards could be considered between the Intra-FactoryMES and the Automation System layer communication and forinteraction in cloud computing environment.

While developing ManuCloud systems the security possibilitiesof several standards (e.g. OCCI, EDIFACT, ebXML, MyOpenFactory,RosettaNet, SEMI Interface-A.) have been studied.

6.2.6. Cloud manufacturing platform levels

The cloud manufacturing platform is split into four functionallayers which are shown in the following table and which can bemapped with the four ATHENA layers as shown in Table 4.

The layers introduced in the table are identical to the ones listedin the taxonomy (refer to Fig. 3).

Within the factory-specific IT systems like ERP and MES,specific data formats are used. Those are mapped to a uniquedescription format for factory capabilities by means ofmanufacturing service descriptions (refer to previous section).The extraction of those descriptions from intra-factory IT systemshas to include harmonization mechanisms which adapt thefactory-internal syntax and semantic to the one provided by themanufacturing service description schema. This mapping enables


to integrate manufacturing capabilities on platform level and tohandle them in a consistent way. The service descriptions arepublished to the platform Manufacturing Service Managementwhich archives the descriptions, but also supports their composi-tion to higher level manufacturing services.

The execution of those manufacturing services is managed bythe ERP and MES functionalities on cloud level. This means thatprocess chains which are configured, e.g. by service aggregation arecontrolled there. The functionalities of this layer include ordermanagement, planning and scheduling of processes and processsteps (i.e. service execution), tracking of manufacturing servicesand related products, quality management, etc.

On business level, the platform provides generic functionalitiesfor the management of member organizations which also includestheir integration by means of individual cloud connectorimplementation. Besides this, virtual enterprises are establishedand managed within this layer based on the specified services andprocesses.

6.2.7. Performance and reliability

The reliability (availability) and performance in cloud-basedsystems are very important for the customers. The calculation ofthese indexes happens by using different indicators. Theseindicators can be technical related (response time, service time,power consumption (reducing migration, data handling, volume ofrequests that could be fulfilled, etc.)) or financial ones. In case ofcloud platforms on the market the performance analysis can focuson Return of Investment (ROI) as well. Cloud service reliability canbe defined how probable the cloud can successfully provide the




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requested service by the users. Cloud service performance isconcerned how fast cloud can provide the requested service.

As the ManuCloud is a prototype system the focus ofperformance analysis was on functional characteristics, onefficiency, on usability and other characteristics that apply newmethods and technologies in order to demonstrate the positiveresults of the work.

� Evaluation of functional requirements (based on demonstrationscenarios developed from use cases).� Evaluation of systems – the security system has been selected as

an important element of the whole information system (e.g. interms of data level access control).� Evaluation of human computer interaction, interfaces (GUI) –

usability evaluation.

Non-functional requirements were not analysed (like perfor-mance of the system, response times, etc.) as in case of a prototypesystem this type of evaluation would produce non-relevant results.Based on the evaluation results some modifications have beendone in different modules of the ManuCloud system.

6.2.8. Comparing ManuCloud architecture and Use Case I

Based on the above description, ManuCloud fits Use Case Iwhere a permanent virtual enterprise interacts with the end user(consumer) through a community cloud (Fig. 6). The communitycloud operates based on a PaaS service model. The descriptions inthe taxonomy classes ‘‘Cloud Service Types’’ and ‘‘Cloud Deploy-ment Types’’ meet the main characteristics of the ManuCloudarchitecture and operation.

The characteristics of the ManuCloud environment can beinserted into the classes/subclasses of the proposed taxonomy inthe following way:

� Class1: Actors in the Architecture – consumer, broker, serviceprovider, cloud, virtual enterprise (member enterprises).� Class2: Cloud Service type – service type is ‘‘Platform as a

Service’’ as the Cloud Connector has been developed inside thecloud.� Class3: Cloud Deployment type – manufacturing community

cloud.� Class4; Cloud interoperability type and levels – application- and

sector-specific standards are used in this case – application, data,runtime and middleware layers participate in the communica-tion.� Class5: Duration of VE connection – the VE is a permanent one as

the manufacturing community cloud collects a group ofenterprises belonging to the same narrow sector.� Class6: VE interoperability levels – process, service, application,

and data levels are involved. ManuCloud project develops anoverall manufacturing service description that combines productand production aspects as well.

The classes and the relevant sub-classes of the presentedtaxonomy have been identified in the ManuCloud descriptiondemonstrating that the taxonomy is appropriate for representingreal, industrial VE-CC systems as well.

7. Conclusions

Cloud computing technology is under development today, butits basic characteristics look very promising for the networkedenterprises. Interoperability in cloud computing has a basic role asfor networked enterprises, so an overview has been given on thestatus of cloud interoperability standardization activities. It can bestated that important standards are missing but very concentrated


efforts are done on international level to develop the strategicallymost important standards. Reference architectures, taxonomieshave been developed to define systematically the missing standardsand parallel build into these systems the existing applicable ones.The situation alters very quickly, so, the most important cloudstandards will be available in the not too far future.

A taxonomy has been presented for analysing connectionsbetween cloud – and VE architectures as this type of informationsystems will play important role in different service andproduction sectors in the coming years. The taxonomy focuseson the connection of cloud and VE IT architectures taking intoconsideration interoperability aspects as well. First level classesare, e.g. the actors, cloud service types, cloud hosting types, cloudand VE interoperability levels. Based on the taxonomy four usecases have been introduced that are/will be typical in VE-CCconnected systems.

The intermediate results of the ManuCloud project also havebeen described. In the frame of this project a new promisingapproach, the MaaS (Manufacturing-as-a-Service) has beendeveloped in order to increase qualitative and quantitativeproduction network flexibility and to manage the providedmanufacturing services throughout the network via a so-calledCloud Connector. Services can be searched, aggregated, andconfigured by end-customers then the configured service instancesare sent back to the manufacturers in order to check theiravailability by means of up-to-date data from their internal ITsystems. The implementation of the Cloud Connector wassuccessful but a proprietary SW module had to be developed asthere was no available standard for some functions yet. The classesand the relevant sub-classes of the presented taxonomy have beenidentified in the ManuCloud description demonstrating that thetaxonomy is appropriate for representing real, industrial VE-CCsystems.

Based on the market researches and on theoretical and practicalworks introduced in this paper it can be predicted with goodchances that connecting VE and cloud computing will result veryefficient manufacturing enterprises but parallel very complex(hybrid) clouds can be generated. In these cases interoperabilityand portability will have even more important role then in caseconventional enterprises apply cloud technology.

Acknowledgement

The part of the research work described in the article has beendone in the frame of the FP7EU project ‘‘Distributed Cloud productspecification and supply chain manufacturing execution infra-structure’’ (ManuCloud), No: 260142.

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Dr. Istvan Mezgar is a senior researcher and deputyhead of CIM Research Laboratory at the Computer andAutomation Research Institute, Hungarian Academy ofSciences. He is an Associate Professor at the Departmentof Manufacturing Science and Engineering, BudapestUniversity of Technology and Economics (Dr.Habil.:2006 from the TUB). He is Editorial Board member ofnumerous international journals, member of IFAC WG5.3, has more then 130 scientific publications atinternational forums. He served as visiting scientist/professor several times at different universities/re-search institutes of Italy, Japan, New Zealand andRepublic of Korea. His current interests focus on

networked organizations, wireless communication networks and their security,cloud computing, trust building in networked IC systems.

Ursula Rauschecker is a project manager and seniorscientist at Fraunhofer Institute for ManufacturingEngineering and Automation (Fraunhofer IPA). Sheholds a diploma in mechatronics and now is active inthe field of manufacturing IT. Among other activities,she has successfully contributed to numerous publicand contract research projects in production IT withspecial regard to systems integration acrossmanufacturing sites/throughout the supply chain.







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the challenge of networked enterprises for cloud computing interoperability

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