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Minutes, 05 June 2015 interim, 6TiSCH WG

Note: timestamps in PST.

Connection details


Taking notes (using Etherpad)

  1. Thomas
  2. Pascal

Present (alphabetically)

  1. Thomas Watteyne
  2. Pascal Thubert
  3. Alexandre Pelov
  4. Elvis Vogli
  5. Giuseppe Piro
  6. Guillaume Gaillard
  7. Kallol Das
  8. Malisa Vucinic
  9. Maria Rita Palattella
  10. Michael Richardson
  11. Michel Veillette
  12. Nicola Accettura
  13. Pat Kinney
  14. Patrick Wetterwald
  15. Pouria Zand
  16. Qin Wang
  17. Rene Struik
  18. S.V.R.Anand
  19. Sedat Gormus
  20. Tamer Elzayyat
  21. Xavi Vilajosana
  22. Zuo Chen

Action Items

  • Chairs to check announcements for 7 vs 8AM pacific
  • Xavi to sync with Nicolla on Ranks in the diagram by next Friday (June 12)
  • Malisa to start a thread on security settings for in MAC for K1 and K2 for text to be included in example section
  • Xavi to publish 08 and Pascal to push to IESG by next Friday (June 12)


  • Administrivia [4min]
    • Approval agenda
    • Approval minutes last call
    • update IETF93
    • chair's statement on refocusing the work
  • draft-ietf-6tisch-minimal
    • security text statement [10min] (chairs)
    • update minimal with RPL DAGrank [10min] (Nicola Accettura)
  • draft-ietf-6tisch-coap
  • AOB [1min]


  • [07.??] Meeting starts
    • Just received deck from Alex, added to the slides
    • RenĂ©: meetings are announced at the old time (8AM) need to chage this in the future
    • Thomas todo for chairs, check the announcements
  • [07.??] Administrivia [4min]

    • Approved agenda
    • Approved minutes last call
    • update IETF93
      • requested 2.5 hours early in the week
      • 17-18 July plugtest
      • 19 July hackathon
      • need to publish preliminary agenda in 2 weeks
      • then draft cut off 2 week before IETF
    • chair's statement on refocusing the work
      • need to wrapup coap and interface document
      • need more attention. Proposal: a sprint
      • 2 weeks focus per document. Additional webex on 15th and 29th 4PM CET proposed to focus on the drafts
      • first interface, presenting at the interim
      • idea is a respin for each draft by IETF cutoff
      • Qin: find for me (Qin is in Pennsylvania)
    • news on detnet
      • BoF for WG forming (2h)
      • close to final charter
      • chairs for BoF have accepted
      • will be highly focused on problem statement
      • new draft: 6TiSCH requirements for detnet
      • idea: feed requirements
      • important link with interface/coap drafts
      • important to move forward quickly before interface draft published
      • 6TiSCH is a feed for detnet, pce/teas/ccamp is a technology provider
  • [07.??] draft-ietf-6tisch-coap

    • preparation: please read
    • mail thread: YANG hash clashes & full extended name [20min]
      • 75 emails in the past couple of weeks
      • 6TiSCH is positioned as having requirements to COMI
      • Thanks Michel, Alex and others
      • Thomas: 6TiSCH would like to avoid interactions with nodes as they come up, like fetch a file or a resource zero or whatever. This may saturate the limited bandwidth.
    • Alex: on goals, summarizing discussion with Micehland Andy
      • We want short ID sand no hash clash
      • Want 1 byte instead of 5 bytes for the hash and CBOR
      • Proposed compression by zero elimination
      • IDs 1 to 255 -> yang and cbor result in 1 octet
      • how can we force that hashid start with 0?
      • propose to use these for hash aliases frequently used
      • e.g. cell id, channel id, time slots
      • assignment? one way is to say that alias 0 is meta resource, querying 0 would tell you what's happening
      • can use POST to setup mapping
      • hash collisions: Michel's idea is to use managed module IDs and deterministic value. 20 bits module ID. Remaining 10 bits is datanode ID
      • Michel supports the proposal. Sadly missing people from COMI..
      • Michel: in some situation the node must fetch both the list of module and ?
      • Thomas: do I need to retrieve the list of module? In the context of 6TiSCH, a node will have the 6TiSCH resources and 6TiSCH knows how to hit those whatever else is on the mote. No required discovery
      • Michel: yes but is another module augments the 6TiSCH model, this goes under the 6TiSCH model and we need the module list
      • Michel: can save up to 8 bytes on each request, makes a lot of difference
      • Thomas: 6TiSCH is a small subset of what COMI can do, let us keep it very simple. Q: can we retrieve a version number (like rfc nb) so I know which level of 6top interface and then I know exactly what that model exposes?
      • Michel: 2 problems. No versioning in COMI. NO notion of module. I create one for definitions but the names/hashes end up mixed in the same bucket. In Alex's proposal there is a module ID in the identifier.
      • Alex is we accept that 0 is the meta resource. GET to 0 will give a hash value of the alias assignment and if that hash is known, all set; else more introspection is required.
      • Michel: Alias does not solve all problem, there is also the node ID and we do not have that construct.
      • Thomas: in the slides, I'm showing what would be nice o have and versioning would be one such thing.
      • Thomas: Proposal for 6TiSCH to have well known alias and not use mg.
      • Michel: will work
  • [07.??] draft-ietf-6tisch-minimal

    • security text statement [10min] (chairs)
      • Thomas: to RenĂ©'s point we'd better stay on the Dallas text since we did not get consensus on update. We need this in for the plugtest
      • Rene: What is Dallas text
      • Thomas: the text that was submitted to the ML by Rene with the corrections pointed by Rene Struik.
      • from Rene Struik to Everyone:
      • from Michael Richardson to Everyone: works for me.
      • Pascal: can we have examples from Malisa's work
      • Malisa: will propose text
    • Status on minimal (Xavi) * correction on dagroot pointed out by Nicola
      • added a paragraph in section 10 example to explain little endian reading
      • Nicolla: there is still a mistake, node 1 should be 3 or 4
      • Xavi: will fix
      • Thomas: can you please expose to Nicolla your final for validation
      • Maria Rita: We need to publish minimal before we publish plug test
      • Pascal: we want to push the draft to IESG by end of next week. Let us sove
  • [07.??] AOB [1min]

  • [08.??] Meeting ends