The 6LoWPAN architecture

6LoWPAN is a protocol definition to enable IPv6 packets to be carried on top of low power wireless networks, specifically IEEE 802.15.4. The concept was born from the idea that the Internet Protocol could and should be applied to even the smallest of devices. The initial goal was to define an adaptation layer -- "IP over Foo" to deal with the requirements imposed by IPv6, such as the increased address sizes and the 1280 byte MTU. The final design takes the concepts used in IPv6 to create a set of headers that allow for the efficient encoding of large IPv6 addresses/headers into a smaller compressed header - sometimes as small as just 4 bytes, while at the same time allowing for the use of various mesh networks and supporting fragmentation and reassembly where needed. This paper describes some of the underlying assumptions and decision points made during the development of 6LoWPAN and how the "stacked header" concept is applied so that in using the protocol you only have to "pay for" what you use. It concludes with open problems and challenges for further development and research.