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This page describes the compaction/decompaction of IPv6 headers at the Border Router of the Wireless Sensor Network (OpenLBR):
The packets that come from the Internet to the WSN carry a full IPv6 header. The mission of the OpenLBR is to read the IPv6 header, replace and compact this header into a shorter 6LoWPAN header. The packet with the compacted header then travels across the OpenWSN Network. This involves compacting addresses and removing redundant fields, wherever possible. The details of this procedure are detailed in the IETF document Compression Format for IPv6 Datagrams in 6LoWPAN Networks (draft-ietf-6lowpan-hc-07).
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As a reminder, a 40B IPv6 header looks like this (without options):
We need the following two functions to assemble and disassemble an IPv6 packet into a data structure consisting of the IPv6 header fields, and the IPv6 payload. These functions ease further processing.
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