Technical Summary
Controlling the amount of data transmission is one possible means of
saving energy. In a number of LLN standards, the frame size is
limited to much smaller values than the IPv6 maximum transmission
unit (MTU) of 1280 bytes. In particular, an LLN that relies on the
classical Physical Layer (PHY) of IEEE 802.15.4 [IEEE802154] is
limited to 127 bytes per frame. The need to compress IPv6 packets
over IEEE 802.15.4 led to the 6LoWPAN Header Compression [RFC6282]
work (6LoWPAN-HC).
As more and more protocols need to be compressed, the encoding
capabilities of the original dispatch defined in the 6lo adaptation
layer framework ([RFC4944],[RFC6282]) becomes saturated. This
specification introduces a new context switch mechanism for 6LoWPAN
compression, expressed in terms of Pages and signaled by a new Paging
Dispatch mechanism.
Working Group Summary
There was minimal controversy and rough consensus appears to have been
achieved. The shepherd had initially raised some concerns with the draft
and his criticisms were entertained on the working group list, with the
objections heard and considered in fairness. The consensus of the
working group is that the additional operational complexity of
introducing the paging state variable in the 6LoWPAN parser is worth the
energy savings to be had by not using a more verbose grammar for
extending the dispatch code space while preserving the statelessness of
the parser.
Document Quality
There are at least two independent open-source implementations, i.e.
OpenWST and Kontiki, and both have been tested for interoperability at
an ETSI plugfest event.
Personnel
James Woodyatt is the document shepherd. Suresh Krishnan is the
responsible AD.