1/16 DIANE Project Philipp Obreiter, Michael Klein Vertical Integration of Incentives for Cooperation Universität Karlsruhe, Germany Institute for Program Structures und Data Organization Universität Karlsruhe GERMANY The Second Mediterrean Workshop on Ad Hoc Networks June 25-27, 2003 – Mahdia, Tunisia

2/16 Motivation A C D B is connected to a printer wants to print a document Questions: Why should D offer a printing service to A? Why should B and C forward packages from A to D?

3/16 Autonomy and Elementary Cooperation Typically in Ad hoc Networks: Autonomous devices  devices are free to cooperate or not  tend to be uncooperative due to scarceness of resources (e.g. battery power)  cooperative behavior must be stimulated PrincipalAgent action remuneration

4/16 Conceptual Layering Application Discovery Transport Network Link User Interface Application Discovery Transport Network Link User Interface device Adevice B autonomy border

5/16 Asymmetric Cooperation Patterns Example on the network layer b c d inherent principals inherent agent runs out of remunerations amasses remunerations a  Vertical trading of remunerations

6/16 Overview Vertical interaction Generic model combining vertical & horizontal collaboration Applicability issues

7/16 Vertical Interaction (n+1) Protocol Entity (n) Protocol Entity Conventional vertical interaction (n+1) PE relinquishes resources to (n) PE in order to consume its services resourcesservices

8/16 Vertical Trading of Remunerations (n+1) Protocol Entity (n) Protocol Entity remuneration In the presence of incentive schemes a vertical flow of remunerations is required inh. agentinh. princ.

9/16 Introductory Example (1) A PDA user repeatedly prints documents User PE Appl. PE PDA User PE Appl. PE Printer Vertical trading of remunerations: The PDA user pays for printing documents The printer owner is refunded for the operation costs

10/16 Introductory Example (2) The communication between the PDA and the printer is routed Appl. PE Netw. PE PDA Appl. PE Netw. PE Printer User PE Netw. PE Router

11/16 Introductory Example (3) Combined view: Appl. PE Netw. PE PDA Appl. PE Netw. PE Printer User PE Netw. PE Router User PE

12/16 The Generic Model of Stimulated Cooperation (n+1) PE (n) PE Device A (n+1) PE (n) PE Device B The generic model combines Vertical interaction and trading stimulated cooperation

13/16 Problems with Vertical Trading Main Problem Protocol layers are encompassed by different incentive schemes: different remuneration types (“currencies”) closure constraints of incentive schemes  Then, protocol entities cannot vertically trade remunerations

14/16 Vertical Trading of Remuneration in Practice (n+1) PE (n) PE Device A (n+1) PE (n) PE Device B Is vertical trading of remunerations implementable?

15/16 Conclusion Summary cooperation beyond autonomy borders requires incentives vertical trading of remunerations prerequisite for the effectiveness of the incentive scheme we proposed a generic model that combines vertical and horizontal collaboration illustrated how vertical trading of remunerations is implemented Future work conception of appropriate transaction protocols that support vertical trading of remunerations implement the concept

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17/16 Elementary Cooperation PrincipalAgent action remuneration service ConsumerProvider check Application Layer forwarding SenderRouter reputation Network Layer

18/16 Account Based Incentive Schemes: Properties Remuneration mechanism every entity possesses an account accounts stored on virtual banks principal issues a check agent accesses a virtual bank in order to credit its account Implementation requires static trust mechanisms virtual banks managed by dedicated devices banker nodes accessibility? accounts distributed to account holders tamper resistant hardware

19/16 Reputation Based Incentive Schemes: Properties Remuneration mechanism principal adapts agent's reputation according to its action agent might decrease principal's reputation agent only cooperative if principal has good reputation Implementation couple trust and remuneration local views of reputation may be kept local shared, i.e., disseminated increases effectiveness introduces further opportunities for misbehavior requires stable or localized cooperation patterns

20/16 Vertical Interaction (n+1) Protocol Entity (n) Protocol Entity Conventional vertical interaction (n+1) PE relinquishes resources to (n) PE in order to consume its services resourcesservices Resource assessment makes costs for service provision transparent provides a basis for decision making

21/16 Heterogeneity and Integration What happens if protocol layers belong to different incentive schemes? vertical trading of remunerations goes beyond incentive scheme borders protocol entities cannot vertically trade remunerations Integration of incentive schemes has to cope with heterogeneity with regard to: 1.incentive schemes and encompassed layers 2.incentive schemes and incentive patterns