1. Carnet: A Scalable Ad Hoc Wireless Network System SIGOPS European Workshop, 2000. Authors: Robert Morris, etc., MIT Library of Computer Science Presenter: Shang-Chieh Wu (meou@cs)

2. Outlines Carnets places radio nodes in cars. Grid and a geographic forwarding protocol Misc. Conclusion.

3. Grid: a scalable and dynamic network architecture (Hope) Self-configured. (Hope) Not rely on any fixed infrastructure. (Hope) Support mobility (Hope) Interact with a changing neighborhoods easily (Hope) Proper APIs to support changing in neighborhoods. (Hope) Hundreds of thousands of nodes.

4. Carnet A network of cars equipped with Grid nodes. Each node has an embedded Linux computer, an 802.11 radio, a GPS receiver, and displays for drivers/passengers. Much of Carnet is speculative. Focus on the scalable ad hoc routing.

5. Grid Location Service Geographic forwarding. At each node, a purely local decision is made to forward the packet to the neighbor that is geographically closest to the the destination. No global information involved helps it scale well and cope well with mobile nodes.

6. Grid Location Service (2) All nodes agree on a distributed algorithm f(i) that maps each node identifier to as list of physical locations, express as latitudes and longitudes. f(i) has hash-like qualities that ensure that its values for different arguments are spread out over physical space. The location produced by f(i) act as node i’s location servers. Whenever node i move, it send update info to f(i).

7. Grid Location Service (3)

8. Others Use variable-power radio. Grid-to-Internet gateway. Privacy issue.

9. Conclusion Carnet handle scaling to large numbers of nodes using geographical forwarding and GLS distributed location service.

10. My opinion 2-D hashing for location service is a nice idea. However, the main beef had been used in their other conference paper. What’s the killer application for a carnet with hundreds of thousands of cars ?