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meetings / 140124_webex

Minutes Webex 24 January 2014, 6TiSCH WG

Note: timestamps in PST.

Taking notes (using Etherpad)

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

Present (alphabetically)

  1. Alaeddine Weslati
  2. Diego Dujovne
  3. Giuseppe Piro
  4. Kuor Hsin Chang
  5. Maria Rita Palattella
  6. Michael Behringer
  7. Michael Richardson
  8. Nicola Accettura
  9. Pascal Thubert
  10. Pat Kinney
  11. Patrick Wetterwald
  12. Pouria Zand
  13. Qin Wang
  14. Raghuram Sudhaakar
  15. Rene Struik
  16. Rouhollah Nabati
  17. Sedat Gormus
  18. Thomas Watteyne
  19. Xavi Vilajosana
  20. Yoshihiro Ohba



Action Items

  • Qin to check whether YANG supports a composite key. Maybe by using a new container type.


  • Administrivia [2min]
    • Approval agenda
    • Approval minutes last call
  • cellID and chunk discussion [5min]
  • draft-dujovne-6tisch-on-the-fly [10min] [Diego Dujovne]
  • plugfest: overview participants [10min] [Xavi Vilajosana]
  • draft-pritikin-bootstrapping-keyinfrastructures [20min] [Michael Behringer]
  • AOB [1min]


  • [08.05] Meeting starts
  • [08.06] Administrivia [Thomas Watteyne]
    • Approval agenda

      No issues raised. Agenda approved.

    • Approval minutes last call

      No issues raised. Minutes approved.

  • [08.08] cellID and chunk discussion [Qin Wang]
    • In the CellList, every cell has a cell id
    • A chunk includes multiple cells, should cellID be the foreign key to related CellList and list of cells that form a chunk?
    • [Pascal] What is the cellID used for?
    • [Qin] Local index to reduce the the size of (index, slotOffset. channelOffset, ASN) composite key
    • [Qin] Just and ID, not sure if necessary to detail how is created?
    • [Xavi] Why not use (slotOffset, channelOffset) as composite ID?
    • [Qin] Too many bytes.
    • [Thomas] Can we really use cellID if not unique in chunkcells?
    • [Qin] The list of chunk cells contains all cells to that chunk they are static but have different states (used, not used, etc)
    • [Thomas] Might be useful to have a chunk cell status as attribute, but identify cells only by (slotOffset,channelOffset).

      Action item: Qin to check whether YANG supports a composite key. Maybe by using a new container type.

  • [08.19] draft-dujovne-6tisch-on-the-fly [Diego Dujovne]
    • We agreed to put some order in the issues about the draft. Issues on the bitbucket issues tracker.
    • Solved most of them. Whenever new issue raised on the ML, put in the tracker.
    • Improved the allocation policy, explained why one method might be better than another.
    • Allocation policy: we are doing pre-allocation, estimated bandwidth to parent.
    • Policy means preallocation based on estimates; allocation method is implementations.
    • [Maria Rita] The different of policy and methodology is clear. It looks like single allocation policy can be seen as the single cell allocation method and the group allocation policy can be seen as the bundle allocation policy. Both policies seem to overlap.
    • Diego picked Prof. Pister's contribution as the default algorithm, if disagree please discuss on ML.
    • How to pass direct commands, how OTF talks to other modules, how OTF is called?
    • API from MIBs to get current allocations?
    • Parametrization of the algorithm and other configurations to OTF, how to do it?
    • How to obtain BW request?
    • [Thomas] Format of extra IEs send by 6top is part of the 6top draft.
    • [Qin] To answer how to obtain the BW, this can be done by reading bundle list.
    • [Thomas] The interface internal to a node between OTF and 6top is conceptual only, and far less critical than the communication between distant nodes over the air. We can define the interface for informational purposes, but the important part is what goes over the air.
  • [08.34] plugfest: overview participants [Xavi Vilajosana]
    • Started to organize agenda for plugfest.
    • Identified 6 groups, although still open.
    • Organization:
      • Focus 1: overview of the platforms and groups (short)
      • Focus 2: Interoperability testing (minimal draft)
      • Focus 3: test minimal RPL implementation see if people could implement based on draft.
      • Focus 4: scheduling approaches (centralized and distributed approaches). See if there is any implem of OTF
      • Focus 5: Tools (e.g. analyzers, wireshark)
      • Focus 6: Future improvements
    • Confirmed participants:
      • Linear Technology, Dust Networks (US)
        • Thomas Watteyne
      • Cisco (France/US)
        • Pascal Thubert
      • Universitat Oberta de Catalunya (Spain)
        • Xavi Vilajosana
        • Pere Tuset
      • UC Berkeley (USA)
        • Tengfei Chang?
        • Qin Wang?
      • University of Bari (Italy)
        • Niccola Accettura
        • Gennaro Boggia
        • Alfredo Grieco
      • INRIA (France)
        • Alaeddine Weslati
        • Cedric Adjih
      • Ghent University (Belgium)
        • Pieter de Mil?
    • [Thomas] Can we have some time for "demo" activities?
    • [Xavi] Yes, will add.
  • [08.42] draft-pritikin-bootstrapping-keyinfrastructures [Michael Behringer]
    • Fundamental idea is quite easy to describe. Defined with routers/switches in mind thus looking for feedback for 6TiSCH specific issues.
    • Comes from autonomic networking project where networks configure themselves with no human intervention.
    • Here we use domain certificates, each device will have a device to assert that the device belongs to the network. The rest can be made autonomic.
    • Question: how can we get that domain certificate. Resource consuming but there are stripped down versions of the proposal; in the draft we have many variations.
    • Michael is looking for help to adapt this in a 6TiSCH environment.
    • A new device has some authentication material pre-provisonned, e.g. 802.1AR VENDOR certificates. We use the installed key material at manufacturing to bootstrap a second certificate that is a local DOMAIN certificate.
    • Until after join the node can not access anything (only layer 2 connectivity).
    • Domain certificate boostrap?
    • Registrar forwards the client ID to the device factory (VENDOR) service. We can prevent the device to join until the VENDOR has validated. Then, the VENDOR can keep a record so next time we know that this device is not brand new and may have been tempered with.
    • Back from the VENDOR, the registrar may decide to accept the device or not. For example, policy acceptance if there is an authorization token and the device was brand new;
    • Then, the device can make a decision to proceed to joining the network based on the content of the authorization token signed by the factory (VENDOR). If needed, the VENDOR can control that the device can only join the network for which it was sold.
    • The device need only Link local connectivity to join. It cannot reach Internet until joined. Without 802.1AR certificate, any device can pretend to be some VENDOR. 802.1AR protects against brand/serial usurpation.
    • The proxy does not need outside connectivity; can be deployed in a factory floor. Registrar does need outside connectivity, which can be through additional security layer.
    • [Pascal] The proxy will be a one-hop device, it can be any device. The proxy can be a device that joined the network before.
    • [Thomas] If the proxy is transparent, a mote can be flooding the network as the messages will be routed to the registrar. Is there a way to have some gate-keeping at the proxy?
    • [Michael B.] Yes. Several straightforward method, e.g. throttling.
    • [Rene] How to build the authorization token?
    • [Michael B.] The cloud service has a mapping between customers and node IDs, then the token is generated on the server side.
    • [Michael B.] Without that token, the device may join any network it likes, this is what the authorization token protects
    • There can be different modes of operation depending on how much control the vendor will have vs. knowledge about the deployment
    • [Rene] Need evidence of the cryptographic operations and associated cost.
    • [Michael B.] Normal certificate cryptography, TBD if that fits in a sensor. Smart cards have that facility on board.
    • [Thomas] is draft intended for a particular WG?
    • [Michael B.] Started in Homenet as bootstrap mechanism, was a lot more high level. Found that the problem is more generic and would work in many WGs.
    • [Michael B.] Planning to take through various WG and security area. Lots will happen at next IETF.
  • [09.09] AOB [1min]

    No other business raised.

  • [09.09] Meeting ends