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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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= *** MAX=

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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 Devices  10km x 10km area Simulated user interaction?

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke 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

UbiBay: Ein Auktionssystem für mobile multihop Ad-hoc-Netzwerke CeBIT Demonstration