#36: Last call comments: MCR comments

Comment (by [email protected]):

 6tisch issue tracker <[email protected]> wrote:
     >> 3) I don't think that [I-D.ietf-roll-rpl-industrial-applicability]
     >> will

     >  ever get published. If there is terminology there that we still
 need,
     > I think it should be extracted into the 6tisch-terminology
     > document. While it is an informative reference, the fewer references
 to
     > IDs the better in my opinion.

     >  But this one is really key on why we do RPL on TSCH at 6TiSCH. I'd
     > rather keep it.

 okay.

     >  I suggest we remove the term debate and say this as follows:

     >  " PANA (Layer-3), IEEE802.1x (Layer-2) or some light weight
 variation
     > of those could be used in the join process.  Regardless, the
 security
     > model must ensure that, prior to a join process, packets from a
     > untrusted device are controlled in volume and in reachability.  This
     > piece of the architecture is also deferred to a subsequent volume of
     > the architecture.  A status of the work can be found in Section 13.
 "

 okay.

     >> 7) I don't understand why PANA lives above ACE in figure 3. I think
     >> that
     >  ACE lives above CoAP/DICE (DTLS is missing, but perhaps understood
 by
     > DICE). I think that while technically PANA lives on top of UDP,
 there
     > is of course a layer of EAP, and TLS above it, and perhaps a layer
 of
     > ACE as well. So I'm not saying that this picture needs to be
 changed,
     > just to observe this.

     >  I suggested one, but please come back to me. I think ultimately we
     > need to move all to COMI, including PANA if we adopt it, but none of
     > that is clear now.

 It might be best to remove items from the picture rather than give wrong
 impressions.

     > to the full routing protocol.  The architecture also expects that a
     > 6LoWPAN node that is not aware at all of the RPL protocol may also
     > connect as a host. This can be achieved with an extension to 6LoWPAN
     > ND, adding the capability to carry a sequence number that is used to
     > track the movements of the device, and optionally some abstract
     > information about the RPL instance (topology) that this device will
 be
     > reachable over.  "

 I'm uncomfortable with things that say, "we can do X by extending Y".
 That's always true. ("We can extend 1950s telephone service to do web
 browsing by extending circuit switched networks to do IPv6...")

 Do we need/want to do X?  Is extending Y in our charter already?

     >     When 6LoWPAN ND is coupled with RPL, the 6LBR and RPL root
     > functionalities are co-located in order that the address of the 6LBR
 be
     > indicated by RPL DIO messages and to associate the unique ID from
 the
     > DAR/DAC exchange with the state that is maintained by RPL. The
 DAR/DAC
     > exchange becomes a preamble to the DAO messages that are used from
 then
     > on to reconfirm the registration, thus eliminating a duplication of
     > functionality between DAO and DAR messages.  "

 good.

     >> 13) I think that 6.6 is saying that SEND can not be applied. I
 think
     >> it
     >  should be clearer in saying something like: "The threats against
 IPv6
     > ND as described in RFC3971 apply as well, but the solution can not
 work
     > as the route over network does not permit direct peer to peer
     > communication.  As can be seen in Figure 4..."
     >>

     >  What about

     >  " A typical attack against IPv6 ND is address spoofing, whereby a
     > rogue node claims the IPv6 Address of another node in and hijacks
 its
     > traffic.  The threats against IPv6 ND as described in SEcure
 Neighbor
     > Discovery (SEND) [RFC3971] are applicable to 6LoPWAN ND as well, but
     > the solution can not work as the route over network does not permit
     > direct peer to peer communication.

 good.

     >     Additionally SEND requires considerably enlarged ND messages to
     > carry cryptographic material, and requires that each protected
 address
     > is generated cryptographically, which implies the computation of a
     > different key for each Cryptographically Generated Address (CGA).
 SEND
     > as defined in [RFC3971] is thus largely unsuitable for application
 in a
     > LLN.

     >     With 6LoWPAN ND, as illustrated in Figure 4, it is possible to
     > leverage the registration state in the 6LBR, which may store
 additional
     > security information for later proof of ownership.  If this
 information
     > proves the ownership independently of the address itself, then a
 single
     > proof may be used to protect multiple addresses.

 good.

     >> 14) I think that the relevant parts of [I-D.ietf-roll-rpl-
 industrial-
     >  applicability] need to imported into this document, since this sure
     > looks like a normative reference to me.
     >>

     >  I agree that this spec is fundamental to us. But importing it?

 If it's important, then it needs to be a normative reference. Otherwise,
 it will be a downref that will break publication.

     >  " The architecture defines "soft" cells and "hard" cells. "Hard"
 cells
     > are owned and managed by an separate scheduling entity (e.g. a PCE)
     > that specifies the slotOffset/channelOffset of the cells to be
     > added/moved/deleted, in which case 6top can only act as instructed,
 and
     > may not move hard cells in the TSCH schedule on its own.

     >  "
     >> "6top contains a monitoring process which monitors the performance
 of
     >  cells, and can move a cell in the TSCH schedule when it performs
 bad."

 s/performs bad/performs poorly/


 --
 Michael Richardson <[email protected]>, Sandelman Software Works  -=
 IPv6 IoT consulting =-

-- 
-------------------------+-------------------------------------------------
 Reporter:               |       Owner:  draft-ietf-6tisch-
  [email protected]     |  [email protected]
     Type:  defect       |      Status:  new
 Priority:  major        |   Milestone:
Component:               |     Version:
  architecture           |  Resolution:
 Severity:  In WG Last   |
  Call                   |
 Keywords:               |
-------------------------+-------------------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/6tisch/trac/ticket/36#comment:4>
6tisch <http://tools.ietf.org/6tisch/>

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