Design Considerations for Low Power Internet Protocols
The 6lowpan Internet Standard opens sensor networks up to Internet connectivity by specifying how to format IPv6 packets over low-power wireless links such as 802.15.4. Examining 6lowpan implementations in major embedded and sensor networking operating system, however, we observe that they do not interoperate. I.e., for any pair of implementations, one implementation sends 6lowpan packets which the other fails to process and receive. We explore why these different implementations do not interoperate and find it is due to some of the basic design goals of 6lowpan. Based on these findings, we propose four principles that can be used to structure protocols for low power devices that encourage interoperability between diverse implementations. These principles are based around the importance of balancing memory usage and radio efficiency, and the importance of not relying on Postel's law when dealing with low resource devices. We evaluate and demonstrate these principles by using them to suggest changes to 6lowpan that would make it easier for implementations to interoperate.
READ FULL TEXT