1 G.R. Gangadharan 1, Hong-Linh Truong 2, Martin Treiber 2, Vincenzo D‘Andrea 1, Schahram Dustdar 2, Renato Iannella 3, Michael Weiss 4 1 University of Trento, Italy 2 Vienna University of Technology, Austria 3 National ICT Australia, Austrilia 4 Carleton University, Canada Consumer-specified Service License Selection and Composition 7th IEEE ICCBSS, Feb 2008, Madrid

Talk outline  Motivation  ODRL-S license overview  License-aware service selection and composition framework  License composition for composite service  Directional Matchmaking Algorithm  Illustrating scenario  Conclusion and next steps 27th IEEE ICCBSS, Feb 2008, Madrid

Software as a Service/Utility & License  Web service, SaaS and Service Utility  Can be composed and used by different consumers  Different usage modes (e.g., subscription, pay per use)  etc.  Some questions  How to deal with legal „terms“? Such as noncommercial use  How to associate licenses with a service utility?  How to search, select and compose service utility, taking into account the license? 7th IEEE ICCBSS, Feb 2008, Madrid 3

4 What is a Service License? A license between a service provider (as the licensor) with (could be) many service consumers (the licensees). Describes the use of and access to services in machine interpretable form. A complementary concept for completeness of service usage description. Can be viewed as a superset including SLAs and Policies. 7th IEEE ICCBSS, Feb 2008, Madrid

5 Existing work in Service License? Though there are few examples of service licenses (by Amazon, Google, Yahoo!), to the best of our knowledge, there is no conceptualization of service licensing. These licenses are not machine interpretable. 7th IEEE ICCBSS, Feb 2008, Madrid

6 Why Not a Software License for Services? Services are also software fragments! Services are not targeted as standalone applications. Consumers do not require to download them for local use. Services support composition and reuse. 7th IEEE ICCBSS, Feb 2008, Madrid

What is this paper about This paper: Uses ODRL-S to describe service license Proposes composition and selection of services based on licenses We do not discuss The comparison between ODRL-S with other specifications (e.g., WS-Policy, WSPL, WSOL, WSLA, Slang, etc.) Specifying license is not the focus of this paper See Selecting a service based on functional parameters Contribution: Consumer-specified license-based service selection 77th IEEE ICCBSS, Feb 2008, Madrid

8 ODRL-S (Open Digital Rights Language for Services) Based on ODRL-S ( Subject define the service being licensed Scope of Rights adaptation, composition, attribution, derivation, sharealike, non-commercial use Financial Terms Warranty, Indemnity, and Limitation of liability (WIL) Evolution deal with software evolution/versioning Background: Anatomy of a Service License 7th IEEE ICCBSS, Feb 2008, Madrid

9 Subject Scope of Rights Financial Terms Warranties, Indemnities, Limitation of Liabilities Evolution ODRL Asset Model Extended ODRL Rights Model Representation of SLA in ODRL Representation of Service Evolution in ODRL Background: ODRL-S Service License Model 7th IEEE ICCBSS, Feb 2008, Madrid ODRL-S is nominated by the ODRL consortium as a standard for representing service licensing and currently open for public review at a Working Group (ODRL-S WG).

10 Element Value Background: ODRL-S Service License Structure urn:service-id 1.00 Model Attribute Name Element Attribute Value 7th IEEE ICCBSS, Feb 2008, Madrid

Previous and background work for this paper  License Compatibility analysis [ICSOC’07].  Service selection based on functional parameters  Vector space-based web services search (  Web Services Evolution Management Framework (SEMF)  Managing licenses and other services information  [ICSOC’07] G.R.Gangadharan, M.Weiss, V.D’Andrea, R.Iannella “Service License Composition and Compatibility Analysis”, Proc. of the Intl. Conf. on Service Oriented Computing (ICSOC’07), Vienna, Austria, Sept th IEEE ICCBSS, Feb 2008, Madrid

Service Evolution Management Framework (SEMF) 12 License-aware Service Composition Framework 7th IEEE ICCBSS, Feb 2008, Madrid User interface, Web services consumers Service Selection Request Handler FCA (Function Compatibility Analyzer) LCA (License Compatibility Analyzer) Service DiscoveryResource Management Service Information Functional parameters license clauses Services and licenses Functional parameters Compatible services license links License clauses and links Compatible license

13 urn:uuid:3043abca-90a5-45d bbaa4945ffad urn:uuid:121f3368-aea b0- f0561a T16:37:53+02:00 Licence <link href=" /services/WISIRISFuzzySearchService?odrls"/> <category term="License" scheme=" Software/Licensing/"/> ODRL-S License Managing Service License using SEMF 7th IEEE ICCBSS, Feb 2008, Madrid

14 … Managing Service License using SEMF (cont.) 7th IEEE ICCBSS, Feb 2008, Madrid

Managing Service License using SEMF (cont.) 7th IEEE ICCBSS, Feb 2008, Madrid 15

16 A service provider defines a license for the service and publishes the service with the license. Service consumers are often interested in selecting a service with a particular type of license. Consumer-specified license: A set of license clauses specified by a consumer to be used in the selection of services. Consumer-specified Licenses 7th IEEE ICCBSS, Feb 2008, Madrid

Consumer-specified License-based Service Selection and Composition  Consumers specify licenses for a service to be composed  Our framework  Finds suitable services  Checks if licenses allow services to be composed  Proposes composite service license  Applies Directional Matching Algorithm for consumer- specified and provider-specific licenses in license composition 7th IEEE ICCBSS, Feb 2008, Madrid 17

18 Service License Composition Objective To propose a service license for composite service Composite license associated with composite service Approach Two licenses are compared using our algorithm presented in [ICSOC’07]. A composite service license is generated by Extracting elements of each license and put them together in a single license. Removing redundant clauses. 7th IEEE ICCBSS, Feb 2008, Madrid

19 A set of functionalities and the requested license clauses are provided by a consumer as inputs. Services matching the functionality specified by a consumer is retrieved. LCA searches in the Service Information for the information about licenses of each service being selected by FCA The license of the selected service is compared with the consumer-specified license. Service License Composition 7th IEEE ICCBSS, Feb 2008, Madrid

Service License Composition Algorithm  Find all services to be composed that functional parameters met consumer-specified license clauses 7th IEEE ICCBSS, Feb 2008, Madrid 20 Licenses of all services to be composed must be compatible  Compose a license for composite service  Directional Matching Algorithm

21 Analyzing the compatibility between a consumer specified license and a provider specified service license. Compatibility is directional Based on a set of rules for compatibility between consumer-specified license clauses against unspecified Scope of Rights and Financial Terms in provider- specified license clauses. unspecified Scope of Rights and Financial Terms in consumer-specified license clauses against provider- specified license clauses. Directional Matchmaking Algorithm (DMA) 7th IEEE ICCBSS, Feb 2008, Madrid

22 Two licenses are compatible, if all the respective models in both the licenses are compatible. A model is compatible with another model, if the model types are same and their elements are compatible. An element e 1 is compatible with another element e 2, if: e 1 and e 2 have same type or using redefinition or unspecification [use tables] e 1 and e 2 have equal value. for all nested elements, corresponding elements are compatible. all attributes of e 1 and e 2 are compatible. An attribute a 1 is compatible with another attribute a 2, if the attributes are of same type and the associated values of attributes are equal. Directional Matchmaking Algorithm (DMA) (cont.) 7th IEEE ICCBSS, Feb 2008, Madrid

Illustrating scenario  Current implementation  Not all features have been implemented  Java-based algorithms  Tested in house  Simple scenario  RestauranceService to be composed from  LocationService: provides map/location information  ReservationService: provides table reservations  We need to find possible LocationService and ReservationService suitable to consumer-specified license 7th IEEE ICCBSS, Feb 2008, Madrid 23

Illustrating scenario: examples of licenses 7th IEEE ICCBSS, Feb 2008, Madrid 24 LocationService License ReservationService License Consumer-specified license

25 Consumer-Specified Service License LocationService LicenseReservationService License Illustrating scenario: Consumer Specified SL Composition Compatible Compatible 7th IEEE ICCBSS, Feb 2008, Madrid

26 LocationService License ReservationService License Illustrating scenario: Consumer Specified SL Composition Compatible 7th IEEE ICCBSS, Feb 2008, Madrid

27 Illustrating scenario: Resulting Composite Service License 7th IEEE ICCBSS, Feb 2008, Madrid

Summary and next challenges  Mechanism to specify and associate licenses with services  To support consumer-specified, license-aware service selection and composition, motivated by SaaS and service utility models  Foundation study for our next steps:  How to realize and provide a full implementation of service license model for SaaS/service utility  Validation of a real system with license-aware selection and composition  License enforcement for services 287th IEEE ICCBSS, Feb 2008, Madrid

29 Thanks for your attention! Feedback, suggestion, research collaboration are more than welcome! Hong-Linh Truong Distributed Systems Group Vienna University of Technology 7th IEEE ICCBSS, Feb 2008, Madrid