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