1. Distributed Hop-by-Hop Rate Adjustment for Congestion Control in Sensor Networks Presented by: Vipul Bhasin Sapna Dixit Vishal Kumar Singh Manmohan Voniyadka

2. Goal Implement a distributed rate adjustment strategy to minimize congestion Adjust the source rate using congestion factor for better response

3. Design Calculate congestion factor Used queue length, channel load, and retransmission counter Adjust source rate when consecutive congestion factor found to increase Propagate cumulative congestion factor upstream Propagated only when threshold exceeded

4. Code Changes Suppress Message Behavior sendSupressMsg suppressMsgRcvd calcCongestionFactor Source Rate Adjustment (via AIMD) suppressMsgRcvd NAK Implementation (packet dropped from queue as criteria to post NAK) sendNakMsg NakMsgRcvd

5. Experiments Simple Model of VC vs. EC Varied source rates from 5 to 20 EC outperformed VC Lossy Model of VC vs. EC Two models – one-hop and generated (from lossy builder) Comparable results in generated and EC outperformed VC in one-hop Lossy Model Topology of VC vs. EC EC outperformed VC in new lossy topology

6. Results

7. Pros/Cons Pros Higher Responsiveness Local decisions can be made based on global congestion scenario NAK counter better estimates congestion Cons More suppress messages due to greater propagation of congestion factor