Re: [6tisch] Comment to draft-wang-6tisch-6top-coapie-01.txt

[Tero Kivinen <[e-mail]>]

Pat Kinney writes:
> As you know from subclause 13.4 of IEEE 802.15 WG’s Operation
> Manual, IEEE 802.15 WG needs a letter (or email attachment) from an
> IETF authority that could enforce the assurances necessary for the
> release of ID number assignment (s) from IEEE 802.15. I was thinking
> that IANA could be that authority. I can expedite the request within
> IEEE 802.15’s ANA once we receive that letter.

If my reading is right then there will be one assignment for the whole
IETF, so we most likely would like to make RFC to specify how it is
splitted for different IETF protocols. I do not think COAP is the only
one in IETF who will ever want to use 802.15.4 payload IE. Most likely
adding one byte at the start of payload IE would be enough as
multiplexer for the rest of the payload...

On the other hand as I already told that 802.15.9 already does that
and even more, and the multiplex id there is 16-bit so getting numbers
from there is easier, and getting one number for CoAP would be no
problem etc.

Btw, the overhead of 802.15.9 is as follows:

If frame fits in one 802.15.4 frame 1+2 = 3 octets (1 for MP IE
control, and 2 for ethertype).

If it does not fit in one frame, and needs to be fragmented, then the
overhead will be 1+1+2+2 = 6 octets (1 for MP IE control, 1 for
fragment number, 2 for total payload length, and 2 for ethertype) for
the first frament and 1+1 = 2 octets (MP IE control, fragment number)
for rest of fragments.

In addition to that there is of course MAC header, Header IE
termination IE, and Payload IE header overhead for each fragment.
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