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Minutes Webex 13 December 2013, 6TiSCH WG

Note: timestamps in PST.

Taking notes (using Etherpad)

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

Present (alphabetically)

  1. Diego Dujovne
  2. Dominique Barthel
  3. Elvis Vogli
  4. Guillaume Gaillard
  5. Ines Robles
  6. Kuor Hsin Chang
  7. Maria Rita Palattella
  8. Pascal Thubert
  9. Pat Kinney
  10. Pouria Zand
  11. Qin Wang
  12. Raghuram Sudhaakar
  13. Thomas Watteyne
  14. Tina Tsou
  15. Xavi Vilajosana



Action Items

  • Thomas to repeat best practice for issue tracking on ML, asking for comments.
  • Pascal to post updated list of milestones to ML.
  • Thomas to create preliminary a list of participants. Once ready, send list and goals of interop to ML.
  • Maria Rita to propose changes in terminology to ML, and make changes to draft.


  • Administrivia [10min]
    • Approval agenda
    • Approval minutes last call
    • security architecture
    • issue tracker usage
    • new ACE mailing list
  • 6TiSCH Milestones [5min]
    • update
    • Interop test ?
  • YANG and SNMP [20min]
    • YANG model compiler
    • RFC6087
    • draft-vanderstok-core-comi-01
  • definitions (new terms) [10min]
  • OTF draft [10min]
    • initial comments
  • AOB [3min]


  • [08.05] Meeting starts

    Pascal starts recording

  • [08.06] Administrivia
    • Approval agenda

      No issues raised. Agenda approved.

    • Approval minutes last call

      No issues raised. Minutes approved.

    • Security Architecture discussions
      • On-going discussions for security-focused architecture document
      • To be merged in main architecture
      • Looking for authors that define the architecture of the security as a separate document and merge eventually to the architecture draft.
      • Pascal and Thomas contacted Michael Richardson and it seems that there is some interest on doing that.
    • Holiday break
      • No call on 27 December 2013
      • No call on 3 January 2014
    • Shepherd
      • Chairs are in the process of assigning shepherds to WG documents.
      • Shwetha Bhandari accepted to shepherd the architecture draft.
    • issue tracker usage
      • rules:
      • For individual submissions
        • Tracked by Bitbucket issue tracker
        • [Thomas] encourage authors to use bitbucket issue tracking for personal submissions
        • [Thomas] editor manages issues there
        • [Thomas] When the new revision is published issues can be closed.
      • For WG documents
        • IETF issue tracker used
        • Managed by chairs
        • New revisions need to address all issues
        • Issue closed only when new revision published
      • Discussion
        • No issues raised.

          Action item: Thomas to repeat best practice for issue tracking on ML, asking for comments.

    • new ACE mailing list
  • [08.18] milestones
    • updates allow ADs to do preliminary review of our drafts before formally submitting to the IESG. Minimal and 6top for early 2015.
    • updated proposal:
      • 12/2013 – WG to adopt 6TiSCH terminology
      • 12/2013 – WG to adopt IEEE802.15.4e TSCH overview
      • 12/2013 – WG to adopt 6TiSCH architecture
      • 12/2013 – WG to adopt 6TiSCH minimal configuration
      • 04/2014 – WG to adopt 6top draft(s)
      • 04/2014 – WG to adopt 6TiSCH data model for CoAP
      • 08/2014 - Submit YANG data model in 6top draft for preliminary OPSDIR review
      • 08/2014 - Submit 6TiSCH architecture for preliminary SECDIR review
      • 11/2014 – Submit first draft of 6TiSCH minimal configuration to the IESG
      • 11/2014 – Submit first draft of 6top draft(s) to the IESG
      • 11/2014 – Submit first draft of 6TiSCH data model for CoAP to the IESG
      • 12/2014 – Submit first draft of 6TiSCH terminology to the IESG
      • 12/2014 – Submit first draft of 6TiSCH architecture to the IESG
      • 12/2014 – Evaluate WG progress, propose new charter to the IESG
      • 06/2015 – 6TiSCH Minimal and 6top draft(s) in RFC publication queue
      • 12/2015 – 6TiSCH architecture and terminology in RFC publication queue
    • any issues?
      • [Pascal] security architecture could be delayed a little bit.

        Action item: Pascal to post updated list of milestones to ML.

    • Interop
      • [Thomas] contacted different people to see interest. Interest from OpenWSN and a couple of companies.
      • [Thomas] keep it simple: minimal draft to start with.
      • [Thomas] What is really needed now if an interop chair.
      • [Pascal] IPSO could help out.

        Action item: Thomas to create preliminary a list of participants. Once ready, send list and goals of interop to ML.

  • [08.??] YANG and SNMP
    • Idea was that people from NETCONF, RESTCONF people to join and discuss about that.
    • [Qin] Summary of the 6top draft evolution. Going to focus on YANG model next. 6top draft is split in 2 parts: interface and sublayer, the interface contains the command list but the YANG model still is empty. Work in progress.
    • YANG model compiler
      • [Thomas] The YANG language defines the syntax and semantics of datastore content, operational data, custom protocol.
      • [Thomas] NETCONF is a protocol that enables you to manage resources. It is too heavy to be implemented in a node.
      • [Thomas] RESTCONF is a RESTful version of NETCONF, based on REST. Datastores are defined in YANG and are accessible through HTTP. It only implements a subset of NETCONF. It is over HTTP but not to CoAP, so it is not very well aligned with our constrained devices.
      • [Thomas] AFAIK, no on-going work on a constrained version of RESTCONF, i.e. where CBOR and CoAP replace JSON and HTTP, respectively.
    • draft-vanderstok-core-comi-01
      • CoRE Management Interface (CoMI). Using CoAP to manage MIB, can be seen as integration of SNMP into CoAP.
      • Peter will present them to the group when he submits a new version, tentatively first half January.
  • [08.33] definitions (new terms)
    • [Maria Rita] Goal of today: identify new term and discuss first draft of definitions
    • current definitions:
      • [Maria Rita] presents the current definitions of cell and bundle.

        Cell: A single element in the TSCH sloframe, identified by a slotOffset value, a channelOffset value, a slotframe_ID and Hopping_Sequence_ID. A cell can be scheduled or unscheduled. During an unscheduled cell, the node does not communicate. When a cell is scheduled, it is assigned a MAC-layer slotframe identifier, a neighbor MAC address (which can be the broadcast address), and one or more of the following flags: TX, RX, shared, timeskeeping, hard. A broadcast cell is an alias for "a scheduled cell with neighbor address the broadcast address". Bundle: A group of equivalent scheduled cells, i.e. cells identified by different [slotOffset, channelOffset], which are scheduled for a same purpose, with the same neighbor, with the same flags, and the same slotframe. The size of the bundle refers to the number of cells it contains. Given the length of the slotframe, the size of the bundle translates directly into bandwidth, either logical, or physical.

      • [Xavi] the current definition of cell contains the hard flag. Given the recent discussions about the relationship between TSCH and 6top, we need to differentiate this flags from the shared, TX, RX, timekeeping.
      • [Pascal] +1. hard/soft applies to the way the schedule is managed, not to the cell itself.
    • new definitions
      • (un)schedule(d)
        • [Thomas] Suggests to separate the definition in 3 parts (unscheduled, scheduled, scheduling)
        • [Thomas] in summary, let's take out the hard/soft qualifier from the cell definition and add a separate definition for hard cell and soft cell.
        • [Thomas] objective of the terminology draft is to serve as an index (dictionary) of ALL the terms we want to make sure everyone understands as we understand.
        • [Maria Rita, Qin] confusion between schedule, reschedule, allocate, reallocate
        • [Pascal] let's avoid synonyms
        • [Pascal] re-schedule: move a cell, it is another entry in the time-freq metric, it only involves one cell.
        • [Thomas] suggestion: use schedule and reallocate only. reallocate: change the location of the same transmission unit between same peers.
      • allocate

        Short on time, let's continue over ML.

      • reserve

        Short on time, let's continue over ML.

      • chunk

        Short on time, let's continue over ML. Action item: Maria Rita to propose changes in terminology to ML, and make changes to draft.

  • [08.58] OTF draft
    • update changes
      • [Diego] working on new draft version with co-authors.
      • [Diego] replace Pre- Post- and Hybrid approaches with a one: single cell or group cell allocation. This is a simple approach.
      • [Diego] Define a method to track the cell usage on bundles.
      • [Diego] Need 6top bundle functionalities to update draft allocations policies.
    • initial comments
      • [Thomas] Suggestion: use only mechanisms already present in published draft. Otherwise makes it not implementable.
      • [Xavi] If the OTF draft requires new functionality, publish requirement on ML, will then appear as feature request ticket associated for e.g. 6top draft.
      • [Thomas] It might be interesting to have a basic/default algorithm in the OTF draft.
      • [Kuor Hsin Chang] +1
      • [Diego] ACK. Will work on adding.
  • [09.08] AOB
  • [09.09] Meeting ends