Minutes interim-2017-lpwan-10: Tue 17:00
minutes-interim-2017-lpwan-10-201710241700-00

Meeting Minutes IPv6 over Low Power Wide-Area Networks (lpwan) WG
Title Minutes interim-2017-lpwan-10: Tue 17:00
State Active
Other versions plain text
Last updated 2017-10-24

Meeting Minutes
minutes-interim-2017-lpwan-10-201710241700

   Connection details
------------------

*    Date: October 24, 2017
*    Time: 8-9AM DST, 17:00 CEST:
https://www.worldtimebuddy.com/?qm=1&lid=2988507,1816670,5391959,5128581&h=2988507&date=2017-10-24&sln=17-18
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*    Meeting number: 208 224 943

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Agenda
------

*    [17:00] Administrivia                                           [10min]
    o    Note-Well, Scribes, Agenda Bashing
    o    Status of drafts (WGLC / forthcoming WGLC)

*    [17:10] LPWAN Overview - WGLC status and updates                [ 5min]
*    [17:15] Fragmentation comments (Carles)                         [10min]
*    [17:25] Update on SCHC fragmentation (Ana)                      [30min]
*    [17:55] AOB                                                     [ 0min]

Minute takers
-------------

*    Ana Minaburo
*    Arunprabhu Kandasamy
*    Alexander Pelov
*    Dominique Barthel

Attendees
---------

*    Alex Pelov
*    Ana minaburo
*    Arunprabhu Kandasamy
*    Dominique Barthel
*    Julien Catalano
*    Carles Gomez
*    Pascal Thubert
*    Laurent Toutain
*    Vincent Audebert
*    Ivaylo Petrov
*    Uday Davuluru
*    Tomas Lagos
*    Arumugam Paventhan
*    Jack Kozak
*    Juan Carlos Zuniga
*    Sergio López
*    Diego Dujovne
*    ? Mark Nowel -no audio-

Past Attendees (previous meetings, for cc)
---------

*    Stephen Farrell
*    Ana minaburo
*    Laurent Toutain
*    Alex Pelov
*    Diego Dujovne
*    Juan-Carlos Zuniga
*    Julien Catalano
*    Sumankumar Panchal
*    Tomas Bolckmans
*    Carsten Bormann
*    Hannes Tschofenig
*    Carles Gomez
*    Diego Dujovne
*    Juan-Carlos Zuniga
*    Paul Duffy
*    A Paventhan
*    Friedhelm Rodermund
*    Arunprabhu Kandasamy
*    Pascal Thubert
*    Samian Kaur
*    Uday Davuluru
*    Alexander Pelov
*    Alper Yegin
*    Ana minaburo
*    Arunprabhu Kandasamy
*    Bob Heile
*    Pascal thubert
*    Laurent Toutain
*    Julien Catalano
*    Juan-Carlos Zuniga
*    Dominique Barthel
*    Russ Housley
*    Lorenzo Vangelista

Agenda
------

*    [17:00] Administrivia                                           [10min]
    o    Note-Well, Scribes, Agenda Bashing
    o    Status of drafts (WGLC / forthcoming WGLC)

*    [17:10] LPWAN Overview - WGLC status and updates                [ 5min]
*    [17:15] Fragmentation comments (Carles)                         [10min]
*    [17:25] Update on SCHC fragmentation (Ana)                      [30min]
*    [17:55] AOB                                                     [ 0min]

Action Items from last time
----------------------------

* Laurent to split the FSM into two FSM (both for sender and receiver) and add
to draft * Ana to change names of ACK/No ACK to shorter names * Arun to publish
the change of the additional column for field lenght * Publish the version by
next Tuesday (October 17th) * Chairs to wait for final IPR statements and
continue with publishing LPWAN Overview document * The ML should discuss the
Time Scale draft

Minutes
-------

*    [17:00] Administrivia  Alexander makes the announcement
    o    Note-Well, Scribes, Agenda Bashing
       Agenda is agreed.
       Minutes of last interim meeting are approved.
       Most action items from last meeting are now done.
       Left to be done: sephard write-up of LPWN overview doc (expect by
       Thursday); discussion on ML of time scale.
    o    Status of drafts (WGLC / forthcoming WGLC)

*    [17:10] LPWAN Overview - WGLC status and updates                [ 5min]
*    [17:15] Fragmentation comments (Carles)                         [10min]

Arrow to the right - downlink, to the left - uplink (puzzles the audience. Most
would expect End-Device on the left, Infra on the right side of the picture).
Description of pb: if ACK is lost in ACK Always mode on downlink fragmentation
(Receiver is End-Device). In some LPWAN technologies, no downlink but right
after an uplink. Sender will never be able to send ACK request unless the
Receiver (End-Device) sends an uplink. Proposal is to allow the Receiver to
re-send the ACK (uplink) on a timer expiration. Dominique: Link layer issue
(e.g. Class A in LoRa). Do we need to solve link issues at IETF? Juan Carlos:
would cause the receiver to drop the packet. We don't want that. Alex: since we
expect a downlink, the End-Device wants to send an uplink. We can allow for
taht. Pb is timer (???) Carles: pb is transmission is blocked. Could re-use
same mechanism as  in ACK on error mode just for the purpose of the downlink
fragmentation. Laurent: Alex: Alex: what we are looking for is an ack to the
ACK. Carles: a possibility could solve the pb for all but last window. Doesn't
need to be perfect. Laurent: another solution is to copy bitmap. Alex: would
like to avoid DL message in LPWAN. We could add another message Alex: Sender
will infer that all fragments reached the Receiver because otherwise the
Receiver would be requesting again and again for the missing fragments. (an
implicit ack)

*    [17:44] Update on SCHC fragmentation (Ana)                      [30min]

Present the changes done in -07 compared to previous one.
Question: description of FSM in Annex or in main test?
Pascal: usually in Annex, not normative.
Ana: will do.
Ana: better description of all-0 all-1, introducing the notion of "abort". The
state machine takes time.. Ana: verify the description of the state machine
With optimisation of bitmap, can encode all-1 abort Optimized bitmap: only one
bit, set to 1 to mean all bits of the bitmap are 1s. set to 0 to mean frist
fragment was lost (leftmost bit in bitmap is 0). Abort from sender to receiver:
All-1 with no MIC and no payload => Abort If the receiver wants to abort -
it uses ACK with FCN=1 and 1 byte = 1 (which differenciates with ACK) Slide 18:
two separate Abort scenarios in the same drawing. The so-called ACK abort is
not an ACK to the Abort immediately above. It's an abort sent by the Receiver,
using an ACK message format. ANaa: MAX_ATTEMPTS to be used Pascal: why don't we
acknowledge the Abort? Laurent: Abort is informational message. We're jsut
being nice to the other end of the link. Should be able to do without the Abort
message. Pascal: will want to move forward with sending packets, not lock
waiting. Laurent: could echo the Abort. Pascal: can't wait for the ack. Case
where Abort sent because link broken. Alex:

*    [17:55] AOB                                                     [ 0min]
Running out of time.
Pascal: need to book a few hours during the IETF meeting to review and sort out
this stuff. Informal review on whiteboard. During the week, after the LPWAN WG
meeting. Alex: why not during the next interim? Pascal: moving slowly. Will do
much better progress during IETF meeting weeek.

5 volunteers
Dominique, Juan Carlos, Carles, Alex, Pascal, Laurent

Alex: yet, still make progress before that. Review docs, comment on ML.

Next meeting in 2 weeks