Subject: [6tisch] Minutes webex 20 June 2014

From: Thomas Watteyne <[email-masked]>
Date: Fri, 20 Jun 2014 11:32:59 -0700

All,

You will find the minutes of the last webex below.

FYI, all the minutes and slides are archived a
https://bitbucket.org/6tisch/meetings/.

Thanks to Xavi and Pascal for taking notes.

As usual, please fix anything we might have missed directly in the e-mail
and reply.

Thomas

-----

Minutes Webex 20 June 2014, 6TiSCH WG

Note: timestamps in PDT.
Taking notes *(using Etherpad)*

   1. Xavi Vilajosana
   2. Pascal Thubert
   3. Thomas Watteyne

Present *(alphabetically)*

   1. Diego Dujovne
   2. Ines Robles
   3. James Pylakutty
   4. Kazushi Muraoka
   5. Kuor Hsin Chang
   6. Nicola Accettura
   7. Pascal Thubert
   8. Pat Kinney
   9. Patrick Wetterwald
   10. Qin Wang
   11. Raghuram Sudhaakar
   12. Sedat Gormus
   13. Thomas Watteyne
   14. Xavi Vilajosana

Recording

   - Webex recording (audio+slides,streaming)
   -
   https://cisco.webex.com/ciscosales/lsr.php?RCID=aaceeff6b70e4287823ce809b08f1b5a
    *[60min]*

Slides

   -
   https://bitbucket.org/6tisch/meetings/src/master/140620_webex/slides_140620_webex.ppt

Action Items

   - *Xavi* to propose wording of "slot duration" text in minimal draft to
   ML.
   - *Diego* to confirm on the ML whether OTF draft can be presented in
   Toronto by one of the authors.

Agenda

   - Administrivia *[Chairs]* *[7min]*
      - Approval agenda
      - Approval minutes last call
      - IETF90 updates
      - ANIMA/UCAN BoF approved for IETF90

      http://trac.tools.ietf.org/bof/trac/wiki/WikiStart#UCANApprovedforIETF90

      - ACE WG approved

      http://tools.ietf.org/wg/ace/

      - Summary ML discussions and call for consensus *[Chairs]* *[5min]*
   - update on plugfest *[Ines]* *[5min]*
      - practical things
      - list participants
   - Update OTF ad-hoc meeting *[Diego,Maria Rita]* *[5min]*
      - summary discussion tracks

      Question: status draft for IETF90?

      - Updated 6top ad-hoc meeting *[Qin]* *[5min]*
      - summary discussion URI path
      - summary wrapper IE draft
   - draft-ietf-6tisch-architecture-02 *[Pascal]* *[5min]*
      - overview updates
   - draft-ietf-6tisch-minimal update *[Xavi]* *[5min]*
      - overview updates
   - presentation to describe/discuss/present track management *[Pascal]*
   *[5min]*
   - next meetings *[Thomas]* *[2min]*
   - AOB *[1min]*

Minutes

   - *[08.05]* Meeting starts
      - *[Pascal]* reminds note well, recorded, etc.
   - Administrivia *[Chairs]* *[7min]*
      - Approval agenda

      No issues raised. Agenda approved.

      - Approval minutes last call

      No issues raised. Minutes approved.

      - IETF90 updates
      - Friday 4th of July cutoff date for draft submission
      - Draft agenda for IETF90 should be published today
      - ANIMA/UCAN BoF approved for IETF90

      http://trac.tools.ietf.org/bof/trac/wiki/WikiStart#UCANApprovedforIETF90

      - new ML discussion about the Autonomic Networking
         - Not a WG forming BoF. Only discussion, and ideas presented. No
         charter has been published (yet?).
      - ACE WG approved

      http://tools.ietf.org/wg/ace/

      - Summary ML discussions and call for consensus *[Chairs]*
      - *[Xavi]* long discussion about minimal slot length. Kris Pister
      proposed to use 10ms slot to be able to use default template. Saves 25
      bytes on EBs, since we only send template ID.
         - Pro: more BW
         - Con: more complicated implementation
      - *[Xavi]* modified this in the minimal draft. Discussion is whether
      we the 10ms is a MUST or a SHOULD.
      - *[Pascal]* Understand we start with 10ms as the default. Can we
      configure something else and send through EB?
      - *[Xavi]* Yes. 10ms, but if you want to change, we can send another
      value through EB.
      - *[Pascal]* other concern is that, if we send 24 bytes in EB, is it
      difficult to implement for nodes?
      - *[Xavi]* from implementation point of view, no particular
      difficulty.
      - *[Pascal]* for the moment, 10ms, and MAY use something else?
      - *[Xavi]* yes, also suggests to use power-of-2 10ms if not 10ms
      (from Pieter De Mil)
      - *[Pat]* will try to find out more. There is a concern from many
      that 10ms inhibits and reduces performance. Will talk to people
to get firm
      details.
      - *[Xavi]* fine, but if we allow for other lengths, not locked to
      10ms, just default.
      - *[Pat]* also heard about factor of two.
      - *[Pascal]* only recommendation from Pieter de Mil. If you have
      another constraint, you can change.
      - *[Thomas]* Pieter proposed to have this power of 2 aligned slots
      - *[Thomas]* Xavi's text makes that a recommendation.
      - *[Thomas]* Why do people believe that going to 10ms will reduce
      performance?
      - *[Pat]* Will coordinate and come back to WG.
      - *[Thomas]* The current the minimal draft is not completely
      compliant with 15.4e, we need to either use 10ms, or 15ms with
extra bytes
      in EB. Believe 15ms time slot template is what OpenWSN in Berkeley used.
      - *[Thomas]* 10ms is used in places like wireless HART so it is a
      decent default.
      - *[Xavi]* Another point raised is that we don't want to complicate
      things, so considering options of duocast is out of scope of
minimal. Very
      important to be clear on that.
      - *[Pascal]* The question was really whether, if I want to share my
      schedule between minimal and some other scheduling approach, the rest of
      network should be 10ms. Seems that, if you have multiple slotframes, all
      should be aligned to same slot duration.
      - *[Thomas]* Usually, multiple slotframes are of the same length.
      - *[Thomas]* It is possible to have multiple slot length in the same
      network, but very "exotic", and wouldn't recommend to follow
that path too
      far.
      - *[Thomas]* It is certainly possible to use minimal draft and some
      dynamic scheduling at the same time in the same network. We need to
      remember, however, that minimal is NOT a MUST in all networks, it can be
      complemented, combined, it is up to the policy of the network.
      - *[Thomas]* The minimal draft is written as a first step to allow
      inter-operability. Is nothing that needs to be carried in all networks.
      - *[Pascal]* let's go back to Xavi's questions about MUST vs SHOULD.
      - *[Xavi]* better to have 10ms requirement.
      - *[Pascal]* if we agree it can be configured to something different,
      might be compliant. Why bar anything?
      - *[Qin]* agree with Xavi, we can set 10ms as default value if there
      is no new size in EB. If somebody wants to define something else, can be
      defined in EB.
      - *[Pascal]* we agree, the question is whether we MUST capability of
      10ms.
      - *[Qin]* we don't MUST or MAY, we just describe IEEE802.15.4e-2012.
      - *[Pascal]* if you can configure the slot length, don't see why MUST
      10ms.
      - *[Thomas]* In reality, the timeslot template is a groupd of 8 or so
      durations, not limited to only the duration of the slot.
      - *[Pascal]* Xavi, can you propose text?
      - *[Xavi]* yes
      - Action item: *Xavi* to propose wording of "slot duration" text in
      minimal draft to ML.
      - *[Thomas]* one important question is what a node does if cannot
      satisfy timings.
   - update on plugfest *[Ines]*
      - *[Ines]* working with Stephanie to get everything ready.
      - *[Ines]* Collecting requirements from participants.
      - 9 participants confirmed == 9 groups of people.
      - Ines and Xavi are working on guidelines
      - There is people that want to join in the next Plugfests
      - *[Diego]* will the plugfest be broadcast online?
      - *[Ines]* We asked for meetecho, waiting for confirmation.
   - Update OTF ad-hoc meeting *[Diego]*
      - *[Diego]* OTF 6top call on how to obtain statistics and interact
      between 6top and OTF. OTF is at Layer 3 and uses best effort track to add
      cells.
      - *[Diego]* discussions needed on ML. Which commands can be used; how
      to extract statistics (direct access to MIB or not); interface with 6top.
      - *[Diego]* enforce the idea that OTF happens when no PCE.
      - *[Diego]* OTF is using a best effort track.
      - *[Diego]* OTF can be used without a PCE.
      - *[Diego]* Need to identify what are the inputs for OTF to decide.
      Bind this with 6top interface.
      - *[Diego]* OTF interface and algorithms need to be decided.
      - *[Diego]* Redefinition pre- and post-allocation mechanisms, using
      thresholds. Hope to have a new draft for the cut-off date.
      - *[Diego]* should not base on specific cells statistics. Use queues
      AND other measurements.
      - *[Diego]* new draft before cutoff day

      Action item: *Diego* to confirm on the ML whether OTF draft can be
      presented in Toronto by one of the authors.

      - *[Pascal]* Some people claim that TDM is wasting resources. The
      6TiSCH architecture has the capability to use slots opportunistically for
      other flows. If the track is not being used, then the slot can be used to
      forward L3 traffic.
      - *[Pascal]* In "normal" networks, there is more traffic incoming
      than the available BW on the track. In a classical network, the traffic
      that cannot be routed is sent in a best effort track.
      - *[Thomas]* the width of the track should be sized for the quality
      of the different links. Might be possible to take shortcuts and
put packets
      again in track. Using the DSCP you can do that.
      - *[Pascal]* with that mechanisms the overprovisioned BW can be
      distributed across different tracks. The goal is to make a track
      individually smaller.
      - *[Qin]* If we want to use OTF to schedule the best effort track. We
      need a statistic for how many times it retry.
      - *[Pascal]* OTF might decide to increase the bundle.
   - Updated 6top ad-hoc meeting *[Qin]*
      - *[Qin]* last week, discussion about how to present WrapperIE.
      - *[Qin]* 3 drafts will be build for 6top, the one presenting wrapper
      IE will be later merged
      - *[Qin]* discussed size and URI path and resource name
      - *[Qin]* summary discussion URI path
         - The problem is how to name URI-PATH. the available payload is
         64bytes if we use blocks of 64bytes, the CoAP packet requires
62 bytes not
         considering URI PATH. With that, we only have 2 bytes for
URI-PATH element.
         We propose to use a pre-defined prefix "/6t" for packets
carrying wrapper
         IE.
      - *[Thomas]* Why "/6t" and then "/6"? As long there is no resource
      called 4 and e the 6t seems overkill, we should drop "/6"
      - *[Qin]* then that blocks the 4 and the e
      - *[Thomas]* Recommends to Qin to coordinate with CoAP draft authors.
   - draft-ietf-6tisch-architecture-02 *[Pascal]*
      - overview updates
         - several issues solved. Moved section 7.5 in section 9.
      - draft-ietf-6tisch-minimal update *[Xavi]*
      - overview updates
         - *[Xavi]* need a clear idea of where we want to go and then will
         publish
      - presentation to describe/discuss/present track management *[Pascal]*

   This was covered earlier.

   - next meetings *[Thomas]*
      - Friday 6/20, 10-11 PDT
         - plugfest
      - Monday 6/23, 7-8am PDT
         - Security DT
      - Monday 6/30, 7-8am PDT
         - Security DT
      - Friday 7/4, 8-9am PDT
         - 6TiSCH webex
      - AOB

   No other Business raised.

   - *[09.05]* Meeting ends