1. UbiBay Erfahrungsbericht zur praktischen Umsetzung eines Auktionssystems für großflächige mobile multihop Ad-hoc- Netzwerke Hannes Frey, Daniel Görgen, Johannes K. Lehnert, Peter Sturm, Systemsoftware und Verteilte Systeme, Fachbereich IV Informatik, Universität Trier

2. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke2 03.04.2003 Metropolitan sized networking Mobile devices  Wireless communication facilities  Localized location computation Direct communication only within transmission range Unpredictable network topology changes due to mobility  Network partitions  Permanent link failures Supply and demand as a fundamental communication pattern Problem: Find an agreement among offerer and requester Problems and assumptions Request Offer

3. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke3 03.04.2003 Possible solutions Flooding of the entire network  Network load  Network partitions Waiting for matching peers in transmission range  User has to walk to the transmission range of a supplier  Low probability to find a match Request Offer

4. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke4 03.04.2003 The marketplace solution Basic idea  Definition of a marketplace  Devices acting on behalf of a user Walking to the marketplace Negotiating at the marketplace Walking back to the home zone Further components R O O O R R O R Request Offer R R R O O O

5. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke5 03.04.2003 UbiBay – A mobile auction system Auction at marketplaces  Low value goods  Direct neighborhood Agents  Auction agent Controls the auction  Discovery agent Lists all auctions at marketplace  Bid agent Bids on behalf of a user 15 10

6. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke6 03.04.2003 UbiBay – Security Issues Maximum bid is the most crucial part Security needs for low value goods? Using a PKI  Securing the maximum bid  Signed agents  Secret sharing 4 4 MAX=4 4 4 4 4 4 4 *** MAX=4 3 4 5 00101101 10110011 01101110

7. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke7 03.04.2003 Middleware for mobile Applications Test applications: auction system, digital ride board, the SOUL application, games middleware components investigated at the moment Hardware Abstraction Agent Platform Agent Transport Marketplace-wide Communication Marketplace Localization Marketplace Creation A1A2A3S1S2S3 …… Application AgentsService Agents

8. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke8 03.04.2003 Agent Transport To and from marketplaces Geographic routing  e.g. greedy algorithm  Additional: course information Messages can be carried over network partitions Message duplication to avoid message losses  Sender keeps messages until reception is acknowledged  Duplicated messages can be detected on the marketplace Losses are still possible  Device crash S D

9. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke9 03.04.2003 Marketplace-wide Communication More reliable communication  High device density  Network partitions are rare  Message loss can be detected Agents stay longer at market Discovery  Broadcast only in a small region Discard messages outside  Flooding or neighbor knowledge broadcasts Negotiation  Topology-based routing  Broadcasts as above Only simple solutions are implemented yet

10. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke10 03.04.2003 Marketplace Management Creation  On demand  Loadmonitoring: split and join Localization  Information dissemination  Super-Marketplaces Collecting information about device accumulation  Hotspot detection  enhanced position-based routing

11. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke11 03.04.2003 Further Aspects Service agents  Creation  Jobs Load Monitoring Duplicate detection Ticket Service Caching of data  Running auctions  Public bill-board L D T

12. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke12 03.04.2003 Simulation of mobile applications Focused on Applications  High level of abstraction  Changeable Network and Mobility-Models  Visualization One implementation for both simulation and real hardware Scalability  Up to 10000 Devices  10km x 10km area Simulated user interaction?

13. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke13 03.04.2003 Evaluation of mobile applications Simulation components on real hardware (Toshiba, iPAQ)  WLAN with UDP unicast/broadcast  Device discovery by periodic broadcasts  Use of GPS receivers  Requires Java VM (J9 IBM) User interaction by Java GUI  Replacement for simulated user interaction Evaluation methods  Hybrid: PDA attached to simulation (RMI)  Evaluation solely on real hardware Advantages of hybrid approach  No thousands of real devices needed  Replay of specific scenarios  Nevertheless get a feeling for the real application

14. UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke14 03.04.2003 CeBIT Demonstration