Clone wiki

meetings / 130628_webex

Minutes Webex 28 June 2013, 6TSCH group

Note: timestamps in PDT.

Note: the Etherpad service we usually use was performing bad during the call.

Taking notes

  1. Xavi Vilajosana
  2. Dominique Barthel
  3. Thomas Watteyne

Present (alphabetically)

  1. Alfredo Grieco
  2. Dominique Barthel
  3. Guillaume Gaillard
  4. Kris Pister
  5. Maria Rita Palattella
  6. Pascal Thubert
  7. Pouria Zand
  8. Qin Wang
  9. Rafa Marin-Lopez
  10. Raghuram Sudhaakar
  11. Thomas Watteyne
  12. Tina Tsou
  13. Tom Phinney
  14. Xavi Vilajosana
  15. Yoshihiro Ohba




  • Approval minutes last call [2min]
  • draft-ohba-6tsch-security-00 [10min]
  • 6TSCH definition [5min]
  • Overview slides [20min]
  • Simulation [20min]
  • Schedule next meetings, AOB [3min]


  • [08.05] Meeting starts
  • [08.06] Approval minutes last call
    > The people on the call approve the minutes.
  • [08.06] Berlin
    • Preliminary agenda posted at
    • 6tsch BoF accepted and scheduled on Tuesday Afternoon (preliminary)
    • [Pouria] Any other 6TSCH related meetings?
    • [Dominique] Looks like most LLN-related meetings on Mon/Tue/Wed, except 6lo which is on Thursday afternoon.
  • [08.08] draft-ohba-6tsch-security-00
    • Thomas presents overview of discussion about draft
    • formal presentation next week or following.
    • goal: requirements on security for the 6tsch networks
    • Summary of comments on the ML:
      • Phase 0- what a mote should have before deployment?
      • add PANA overview on appendix
      • clear statement of interaction with CCM* on 15.4e
      • Footprint and complexity of the proposal. (PKI complexity??)
      • EB protection-- need to be protected. How protected can it be if you have a shared key?
    • [Yoshihiro]
      • agrees to present next week. He will also be in Berlin.
      • Two important decisions we need to make:
        • do we use asymetric key-based operation or not?
        • do we need multiple MAC keys, Or a common network key?
    • [Pascal] Long debate on that question, using profiles we can define different levels of security.
    • [Yoshihiro] need security warnings. Not all levels of security are need for all applications.
    • [Thomas] is that a problem on having different profiles of security?
    • [Yoshihiro] good approach, but need clear differentiation and identify what each profile covers.
  • [08.15] 6TSCH definition
    • Yoshihiro pointed out that 6TSCH was not defined well in the terminology draft.
    • Proposal from Maria Rita:

      6TSCH: IPv6 over Time Slotted Channel Hopping.
      It defines a set of IETF sublayers and protocols (for setting up a schedule with a centralized or distributed approach, managing the resource allocation, etc.), as well as the architecture to bind them together, for use in IPv6 TSCH based networks.

    • [Thomas] De we agree?
    • [Pascal] Replace "etc" by "in particular, for setting..."
    • [Maria Rita] OK.

      Maria Rita to add definition to terminology draft.

    • [Pascal] Do we want to rename 6tus sublayer by something else?

      Pascal to start discussion on the name of the 6tus sublayer.

  • [08.20] Overview slides
    • Pascal presents the overview slides he is using to present work at 6TSCH
    • We can use some of them during BoF.
    • Slide are available is someone wants to use them.
    • No copyright.
    • Centralized vs decentralized.
    • RPL sibling walkable structures.
    • ARC of siblings that join siblings together.
    • use ARCs for forwarding in case of congestion.
    • Routing with PCE
    • Opportunistic track reuse. have a slot that can be reused for one hop.
    • RPL instance ID: global and local rpl instance. Use local instance ID to identify the track id.
    • Coexistance of PCE routes with RPL routes. What happens when routes conflict?
    • TF field in 6LoWPAN header indicate how to compress the flow label
    • draft in 6man that defines the use of the flow label:
    • [Thomas] what is the context of the slides?
    • [Pascal] keep the slides up-to-date with the work so the group can use them and used to clarify architecture.
  • [08.45] Simulation
    • Xavi has done some preliminary simulation to determine whether the purely random approach to scheduling is appropriate for a 6TSCH networks.
    • [Xavi]
      • Goal not to build another NS-2, but just to know how random allocation works.
      • Each node randomly selects the cell in the schedule.
      • With less than 10-20% of allocated cells, the behavior is OK.
    • [Thomas] The plots explore the network's performance almost to the point where it is saturated?
    • [Xavi] Yes
    • [Thomas]
      • Shares desktop and shows a Python-based simulator to see the dynamic behavior of the network.
      • Help wanted to continue work on the simulator.
    • [Pascal] We can extract from the European directive how they envision CCA. Standard being produced by ETSI on behalf on the European Commission. Deals with durations related to CCA. If we implement random scheduling. Found for thought in our algorithm.
    • [Kris] Can you send out this document?
    • [Tom] will send EN 300 328 and associated IEC compliance analysis.
  • [09.05] Schedule next meetings, AOB
    • Summer is here, and people might be on vacation next week, especially in the US. Is the same time OK?

      No problems from the call.

    • Let's have the next meeting on Friday.
    • [Pascal] we need to start talking about the 1.5h in Berlin, and how to go from BoF to WG.
  • [09.08] Meeting ends