Service Composition for Mobile Ad Hoc Networks using Distributed Matching
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This document proposes a distributed service composition approach for mobile ad hoc networks. It involves disseminating service descriptions between nodes to create a distributed service graph (DSG). When a search request is received, the DSG is used to detect compatible services and compose a workflow by finding pre-computed paths between services. The approach is evaluated in a network simulator and shown to reduce composition search time compared to flooding while increasing failures due to graph maintenance challenges with topology changes. Future work includes testing with larger networks and real devices.
Service Composition for Mobile Ad Hoc Networks using Distributed Matching
- 1. Service Composition for Mobile Ad Hoc Networks using Distributed Matching UCAmI 2012 Unai Aguilera and Diego López-de-Ipiña DeustoTech - Deusto Institute of Technology, University of Deusto http://www.morelab.deusto.es 3 December 2012 The degeneration of rationalism 1/6
- 2. Problem definition ►Automatic service composition on MANET ● User or app. → specification of required service ● Description of service inputs and outputs ● Distributed process → Composition / Graph UCAmI 2012 2/18
- 3. Architecture ►Layered architecture → Peer-to-peer nature UCAmI 2012 3/18
- 4. Dissemination ►Service discovery → not central directories ►Nodes propagate service information ● Service input and outputs ►Parameter table ● Table Message → node to node ● Maximum distance for dissemination ● Triggered by ● Neighbour dis/appearance ● Reception of new information UCAmI 2012 4/18
- 5. Dissemination ►Disseminated information is grouped ● To reduce transmitted data ● According to a taxonomy of parameter types ● Equality, subsumption, no-relation ● Only the most generic type is propagated UCAmI 2012 5/18
- 6. Service Discovery ►Uses previously disseminated information ►Searching node propagates an special message ● Required inputs and outputs UCAmI 2012 6/18
- 7. Route Management ►Combined with search process ● Search message → route to start node ● Response message → route to responding node ►Routing table update ● Message processing ● Neighbour dis/appears ►Supported communication ● Unicast ● Multicast UCAmI 2012 7/18
- 8. Distributed Matching ►Detect relations among compatible services ►No centralized solution → distributed information ● No easy way to perform service matching ► Proposed solution ● Create and maintain during topology change ● Distributed Service Graph (DSG) ● Service matching → intermediate nodes ● Detect collisions among compatible parameters ● UCAmI 2012 8/18
- 9. Distributed Service Graph ►Graph distributed across the network → DSG UCAmI 2012 9/18
- 10. Collision Detection 1.Intermediate nodes check propagated information 2.Match compatible I/O parameters → collision occurs UCAmI 2012 10/18
- 11. Collision Detection 3.Search for compatible services → New routes 4.Responses from services → New routes 5.DSG connection update UCAmI 2012 11/18
- 12. Composition Search ►DSG used during composition search ● Obtain a compatible work-flow ● Pre-computed paths ►Searchprocess: 1.Create composition search special services 2.Register special services 3.Connection if compatibility exists 4.Forward search UCAmI 2012 12/18
- 13. Composition Search UCAmI 2012 13/18
- 14. Evaluation ►Network simulator ns-2 ►Extended with AgentJ → Java code ►Simulation parameters ● 30 nodes over a 300 x 300 meters area ● 100 m transmission range ● Random Waypoint → 0-5 m/s uniform dist. ● 54 Mb/s transmission rate ● Max. packet size 1500 bytes ● 30% of the nodes → 1 search/second UCAmI 2012 14/18
- 15. Evaluation Results ►Composition length: 3, 5, 7 services ● 10 executions → average values ● Distributed Service Matching (DSM) ● Compared with Flooding Based Solution (FBS) UCAmI 2012 15/18
- 16. State of the Art ►Service Graph has been previously applied ● Centralized solutions ● Networks with infrastructure ►Semantic descriptions of services already used ● Service described as a whole ● Not their input and output parameters ● More adequate for functional composition UCAmI 2012 16/18
- 17. Conclusions ►Proposal ● Layered architecture: Discovery, Composition ● Response to MANET topology changes ● Avoids centralization ►Composition search time reduction ● Pre-computed DSG ►Increases search failures ● Graph maintenance / Invalid routes ►Future work ● Evaluate with larger networks ● Test with real devices UCAmI 2012 17/18
- 18. Thank you! UCAmI 2012 18/18