System Support for Cross-Layering in Heterogeneous Sensor Stack Rajnish Kumar, Junsuk Shin, Umakishore Ramachandran IES Micromeasurements SensorStack with Cross-layering support Why support cross-layering? Information overlap across layers Spaghetti Coding Modules take inefficient decision DFuse application needs routing information to decide about role migration Linux EMM Performance: Rule computation delay is minimal compared to event handling TinyOS DMM Performance: IES access using cache has much less latency compared to HSN information access. Information Exchange Service (IES) Design Goals: Efficient use of limited memory Simple interface for information sharing Extensibility Asynchronous delivery of the information Complex event notification SensorStack without Cross-Layering Support Application Lifetime Improvement IES Architecture DFuse performance without Cross-layer information DFuse performance with Cross-layer information for role-migration Heterogeneous WSN Application SensorStack Data management module Stackability by using standard data interface Publish/subscribe based shared memory system Fully-associative cache for performance Event management module Adaptability by notifying when to adapt Complex event notification Reactive memory access DRE: Data request event RSE: Rule satisfied event DAE: Data available event EMM: Event management module DMM: Data management module Adaptability Vs. Stackability of protocol layers Adaptability deals with cross-layer data A must for wireless sensor networks Stackability deals with cross-layer functionalities A must for modular design Principle behind SensorStack Decouple data from functionalities