A Location Service for Beacon Vector Routing Chris Baker, Daekyeong Moon, Jorge Ortiz

Motivation and Problem Formulation  Beacon Vector Routing (BVR)  Point-to-point routing scheme  Dynamic beacon-derived coordinate system  Each node in network has an associated node id and a runtime-derived coordinate  Assumptions  Node id’s are unique and unchanging  Beacon Vector Coordinates are subject to change with topology of the network  Current BVR  sends [node_id, BVCoords] mapping through Ethernet backchannel

Key Solution Ideas  Distributed Cache/Lookup Scheme  Consistent hashing to spread the lookup-request load amongst beacons  Cache entry replacement  Explore cache size and replacement schemes to minimize packets moving through network and balance with system constraints (i.e. memory size, power, etc)  Eavesdropping scheme  Nodes eavesdrop packets on route to beacons and cache beacon responses  Nodes respond to beacon request to shorten response time and decrease network traffic

Current Status and Future Plans  Currently implemented/tested:  Initial version of BVR Location Service modules in place (no local caching)  Cache modules in progress  Code tested in TOSSIM  High-level simulator (HLS) in progress for testing different caching schemes  Future Plans:  Integrate local caching into version 0.1 of Location Service  Test and implement cache entry replacement in HLS and TOSSIM  Test BVR Location Service on Motes  Tweak and turn knobs to find best performance/overhead tradeoffs in real test-bed  Implement Beacon election algorithm

Questions?