[6lowpan] Ke Management pre 15.4e

[Robert Moskowitz <[e-mail]>]

I was asked if Key Management can be provided pre-15.4e.  A number of 
concerns were raised about 4e including there are lots of chips out 
there that do not support it.

This is really challenging.

I do not see how to suborn an existing Command Frame to carry a KMP.  I 
would have to define a new one and that would be itself a deviation from 
the existing 802.15 spec.

I do not see how to define a Data Payload Field for KMP that would be 
effective across a number of higher layers.  There is no EthType field 
or similar differentiator.  I suspect that within 6lowpan a new Dispatch 
Type could be defined to carry the KMP.  I leave such specific 6lowpan 
modifications to those that created it.

As I define the KMP shim over the next two months, I would be happy to 
work with some 6lowpan people in developing an ID for its support within 
6lowpan as well.

Or just fake out the little bit of 4e that I will use for supporting KMP 
within 4e.  The basic thought is to use the new Information Element in 
either the Multifunction or Command frame.  And the Command frame mode 
only applies to PANs that use the Associate command.  So 'just' add what 
little you need...