Early Review of draft-ietf-6lo-nfc-10
review-ietf-6lo-nfc-10-iotdir-early-haberman-2018-09-25-00

* Section 3.4 mentions the use of both UI PDUs and I PDUs to carry IPv6
packets. However, Section 3.2 only mentions the use of I PDUs for carrying IPv6
packets. This seems to be a discrepancy that needs to be cleared up.

* Section 3.4 has the formula MIU = 128 + MIUX. Should MIU be MTU?
Additionally, the use of MIUX is only stated as a SHOULD. If the MIU is 128 and
the minimum IPv6 MTU is 1280, shouldn't the use of MIUX be a MUST? The text in
Section 4.8 seems to mandate the use of MIUX (i.e., "MUST be configured with an
equivalent MIU size to fit the MTU of IPv6 packet"). Given that Section 3.2
says that the NFC LLCP does not fragment/reassemble, I am not sure how NFC can
support a minimum IPv6 MTU without MIUX. If it can, can you specify a scenario
where the lack of the MIUX is not a problem?

* Section 4.3 says to use RFC 7217 for generating IIDs. Given the small size of
the NFC address space, should there be some guidance on how the Network_ID
parameter of f() can be used to increase the randomness of the generated IID?

* Section 4.3 refers to RFC 7136, which says that the 'u' bit is meaningless
unless the IID comes from an IEEE MAC address. However, the text then says that
the 'u' bit of the generated IID MUST be set to 0. Why?

* Section 4.5 seems incomplete. Is IPv6-over-NFC only viable in the mesh-under
topology? Are there 6LBR <--> 6LBR scenarios in NFC that need to be described?

* I don't see any technical benefits in Section 5 as it does not specify any
interoperability details.

* I don't see where anything from RFC 4944 is used in this document. The only
text that refers to 4944 says to not use the FAR procedure from 4944. Either
the reference should be removed or this document should specify which parts of
4944 should be applied.