1. CarTorrent : Swarming Protocol for Vehicular Networks

2. Basic Idea
Internet
file
Vehicle-Gateway Communication

3. Basic Idea
Internet
Download a piece

4. Co-operative Download
Internet
Exchange Pieces
Vehicle-Vehicle Communication

5. Protocol Steps Procedure Initiate_download(torrentID)
if (|d0 – dG| < Radio_range) Send_request
if (Recv_Reply) Start_download(chunk)
else Wait for Gateway to fetch
Init_gossip( )
Exchange BitFields
if(|d0 - dG| > Radio_range) Exchange(chunks)

6. Protocol Features Peer Discovery – Gossip based
Piece Selection – Proximity driven
Content Delivery
Broadcast medium leveraged for “communication efficiency”
Reputation System (Tit-for-Tat policy, game-theoretic approach to achieve Pareto Efficiency)
Data Validation using MD5 checksums
Insert graphs of piece selection

7. Simulation Results (Piece Selection)
Proximity Driven Piece Selection performs best

8. Simulation Results ( Gossip O/H)
Gossiping to discover peers has low overhead

9. Deterministic Model n √n
log n

10. Expected Path length
Add the graph and analytical results

11. Analytical Results
Average Delay with √n compared with log n for the wired case and n without co-operative download
Capacity of Ad Hoc Networks limits the exponential growth of “service capacity”
Physical layer aware by reducing the expected path length
Measurements show that hop count performs better than ETX and other routing metrics in presence of mobility since the updates are not fast enough to propagate.
Add analytical results
Theorem
Expected Path Length