Minutes IETF101: 6tisch

Meeting Minutes IPv6 over the TSCH mode of IEEE 802.15.4e (6tisch) WG
Title Minutes IETF101: 6tisch
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Last updated 2018-03-22

Meeting Minutes

# Minutes, IETF 101 6TiSCH WG Meeting #

Note: these minutes are formatted using Markdown.

Agenda and Meeting Information

Meeting        :   IETF 101 Wednesday 21 March 2018
Time           :   13:30-15:00 London time, Wednesday Afternoon session I
(90min) Location       :   Viscount, Hilton Metropole, London, UK Chairs       
 :   Pascal Thubert
                   Thomas Watteyne
Responsible AD :   Suresh Krishnan
URLs           :   http://tools.ietf.org/wg/6tisch/

 Intro and Status
    * Note-Well, Blue Sheets, Scribes, Agenda Bashing
    * Status of the work, link with other WGs                   [ 5min]
    * next 6TiSCH Interop event                                 [ 5min]

 Chartered items
    * draft-ietf-6tisch-6top-protocol-10                        [10min]
      (Xavi Vilajosana)
      goal: in IESG LC, inform about reviews and revision

    * draft-ietf-6tisch-minimal-security-05                     [10min]
      (Malisa Vucinic)
      goal: prepare for WGLC, ask for 2 reviewers, liaise with CORE

    * draft-ietf-6tisch-terminology-10                          [ 2min]
      (Maria Rita Palattella)
      goal: inform about update

    * draft-ietf-6tisch-6top-sfx-01                             [ 8min]
      (Diego Dujovne)
      goal: present editorial updates, discuss readiness for WGLC

    * draft-chang-6tisch-msf-01                                 [10min]
      (Tengfei Chang)
      goal: in "Candidate for WG Adoption", prepare for WG adoption

    * draft-duquennoy-6tisch-asf-01                             [10min]
      (Simon Duquennoy)
      goal: identify components, discuss how to best integrate

 Unchartered items, time permitting
    * draft-vilajosana-6tisch-globaltime-00                     [10min]
      (Xavi Vilajosana)
      goal: assess importance of problem, validity of solution

    * draft-richardson-6tisch-enrollment-enhanced-beacon-00     [ 5min]
      (Michael Richardson)
      goal: discuss the 4 priority fields

    * draft-richardson-6tisch-roll-enrollment-priority-00       [ 5min]
      (Michael Richardson)
      goal: prepare for call for consensus

 Total scheduled time                                          80/90min


* agenda: https://datatracker.ietf.org/meeting/101/materials/agenda-101-6tisch
* slides: https://datatracker.ietf.org/meeting/101/materials.html
* recording: https://www.youtube.com/watch?v=IJILScTmzrU


_(This summary is also posted in the INT area wiki,

During IETF101, the 6TiSCH WG had one WG meeting session, and 3 side meetings.

The **WG meeting** covered 9 drafts, including 3 unchartered -00 drafts.

* `draft-ietf-6tisch-6top-protocol` is in IESG LC. Xavi Vilajosana (author)
gives an update about the changes triggered by the detailed reviews. These
changes are editorial; we do not expect these changes to derail the IESG LC
process. * `draft-ietf-6tisch-minimal-security` is close to WGLC. A comment was
made about using FETCH rather than GET in the join request. **Malisa Vucinic**
(_editor_) to evaluate the use of FETCH and report to WG. *
`draft-ietf-6tisch-terminology` was updated to follow the work of the WG. No
action needed. * `draft-ietf-6tisch-6top-sfx`: discussion about status and
outcome of this document. * `draft-chang-6tisch-msf` is stable and answers a
point in the charter. The authors asks for WG adoption. **Chairs** to confirm
WG adoption on the ML. * `draft-duquennoy-6tisch-asf` presents new interesting
ideas in scheduling function. Discussion about how to integrate with existing
work. **Simon Duquennoy** (_editor_) to work with WG to integrate ideas of the
`draft-duquennoy-6tisch-asf` into `draft-chang-6tisch-msf` (pending bit might
be a different document). * `draft-vilajosana-6tisch-globaltime` introduces new
(unchartered) work on how to give 6TiSCH node knowledge of global time.
Discussions about drift, security. Sense from room is that there is interest.
**Chairs** to assess consensus on whether there is interest to work this draft,
and possibly add to the charter. *
`draft-richardson-6tisch-enrollment-enhanced-beacon` and
`draft-richardson-6tisch-roll-enrollment-priority` introduce new work on how a
node can select the right network and join proxy to join. Discussion on use

The WG meeting was followed by **3 side meetings**, all held in the code lounge:

* a side meeting to discuss the use case for
`draft-richardson-6tisch-enrollment-enhanced-beacon`. The group identified and
agreed on the uses, and Michael Richardson (editor) took the action item to
modify the slides to be presented in the ROLL WG meeting, and the draft. * a
side meeting to prepare the 2nd F-Interop 6TiSCH interop event * a side
hackathon around the OpenWSN reference open-source implementation of the 6TiSCH

Some **"running code"** announcements were made during the 6TiSCH WG meeting:

* 6TiSCH Simulator, release 1.0.0 (https://bitbucket.org/6tisch/simulator/).
Can be used to assess the performance of a 6TiSCH network. * OpenWSN, release
1.12.0 (www.openwsn.org). Reference open-source 6TiSCH stack implementation.
"Golden device" firmware for interop events. * Wireshark, dissectors for all
major protocols contributed to main Wireshark repository.

**2nd F-Interop 6TiSCH Interoperability Event** will be help 26-27 June 2018,
in Paris, organized by ETSI, LIST and Inria.


* notetaker 1:   **Dominique Barthel**
* notetaker 2:   **Jonathan Munoz**
* Jabber scribe: **Ines Robles**

Action items

* **Malisa Vucinic** to evaluate the use of FETCH in
`draft-ietf-6tisch-minimal-security` and report to WG. * **Chairs** to confirm
WG adoption of `draft-chang-6tisch-msf` on the ML. * **Simon Duquennoy** to
work with WG to integrate ideas of the `draft-duquennoy-6tisch-asf` into
`draft-chang-6tisch-msf` (pending bit might be a different document) *
**Chairs** to assess consensus on whether there is interest to work on
`draft-vilajosana-6tisch-globaltime`, and possibly add to the charter. *
**Michael Richardson** to lead a discussion with the 6TiSCH WG about precise
use cases for `draft-richardson-6tisch-enrollment-enhanced-beacon`


* _[13:30]_ (exp. 13:30) meeting starts
* _[13:30]_ (exp. 13:30) Intro and Status (**chairs**)
    * Note-Well, Blue Sheets, Scribes, Agenda Bashing
        * [**Pascal Thubert**] Please note that the Note-Well has changed;
        Includes other policies than just IPR; Look at the BCP documents
        listed. * 6TiSCH relies on documents produced in other WGs, does not do
        everything locally. * 2 slots for 6TiSCH documents at 6lo tomorrow, 1
        at ROLL * [**Thomas Watteyne**] Presents agenda.
    * Status of the work, link with other WGs [**Thomas**]
        * 6TiSCH simulator 1.0.0 just released. Written in python. Captures the
        full 6TiSCH behavior. 2 developers are on-site here. >
        https://bitbucket.org/6tisch/simulator * OpenWSN 1.12.0 just released.
        Support 12 platforms, including the new OpenMote B. >
        http://openmote.com/ * Wireshark dissectors, already contributed to
        official Wireshark >
        https://www.ietf.org/mail-archive/web/6tisch/current/msg05799.html *
        Reserved code lounge for discussions, this afternoon and tomorrow.
        Various topics, related to 6TiSCH. Populate bottom of these minutes to
        add topics for next time.
    * next 6TiSCH Interop event [Thomas Watteyne, on behalf of **Maria Rita
        * 2nd F-Interop 6TiSCH interoperability in Paris, 26-27 June 2018.
        * Scope to be discussed today, 6-8pm today.
* _[13:42]_ (exp. 13:40) `draft-ietf-6tisch-6top-protocol-10` (**Xavi
    * [**Xavi Vilajosana**] This draft is under WGLC. Got comments from 4
    reviewers. Published -10 version as a result. More comments coming,
    discussed here. * comment: Possible race condition, in 3.1.1. To be
    checked. * comment: Added MSF to the list of SF. * comment: IE shows the
    number of cells. Clarification * comment: Clarification for ADD. if want to
    include many candidate cells, need to do multiple ADDs. * comment: Global
    SeqNum? need to be clarified. * comment: Implementor's feedback from Lotte:
    provided example text for clarification. * comment: from Nicola;
    alternative mechanism for cell allocation at bootstrap (the minimal cell is
    likely to be saturated). * Next step: publish -11 and wait for IESG final
    decision. * [**Thomas Watteyne**] any further remarks? Remarks to this
    draft can be rapidly addressed, in order to get the last version published
    ASAP. * [**Xavi Vilajosana**] all responses to comments already in the
    draft source code, only a matter of publishing. * [**Lotte Steenbrink**]
    add a remark on how to react to missing ACKs. Produced own drawing of
    decision algorithm, wondering if this is correct. * [**Thomas Watteyne**]
    session after the meeting to address any remark.
* _[13:51]_ (exp. 13:50) `draft-ietf-6tisch-minimal-security-05` (**Malisa
    * status: -05 published just before cutoff.
    * major change since -04: solved exposure to attack from malicious nodes
    via resource exhaustion. Uses DiffServ Code Point for Join Requests. * when
    a single JRC manages multiple networks, needs to know which network the
    pledge is attempting to join. Resolved with a Join Request payload with
    CBOR payload. * [**Malisa Vucinic**] question to the CoAP experts in the
    room. Should we do a GET with a query? * [**Carsten Bormann**] FETCH is the
    way to go. Can carry a query and an observe. * [**Thomas Watteyne**] join
    nodes the network, allows JRC to reach back the node * [**Michel
    Richardson**] let's not delay WGLC. * [**Malisa Vucinic**] will discuss at
    the side meeting tonight. * [**Thomas Watteyne**] proposed mechanism would
    allow link layer re-keying without disruption? * [**Malisa Vucinic**] yes.
    Current mechanism creates disruption. * editorial changes, Clarifying
    terminology. All terms are listed. "Network identifier" and "pledge
    identifier" mapped to PAN ID and EUI64.. * second major editorial change:
    define the standardization scope of this document * [**Pascal Thubert**]
    6TiSCH defined an IPv6 subnet. Would make more sense that the whole subnet
    has the same security properties? * [**Pascal Thubert**] node can move
    freely between DODAG roots, accurate time. * [**Pascal Thubert**] original
    goal was to build single subnet, RPL roots get time from backbone. *
    [**Tero Kivinen**] clock drifts. PANs initially synchronized, but could
    drift away. * [**Tero Kivinen**] in most cases, part of only one PAN. *
    [**Thomas Watteyne**] see Xavi's presentation on global time later. *
    [**Malisa Vucinic**] next plugtest in June 2018 Paris. * [**Thomas
    Watteyne**] close to WGLC indeed, but let's make sure we understand the
    FETCH issue first. * [**Suresh Krishnan**] OSCORE stuff is in IESG review.
    Got a DISCUSS from a Security AD, looks complicated. Go ahead with your
    draft, don't wait for OSCORE. * [**Goran Selander**} working on this
    DISCUSS, doesn't look this complicated to me. > **Action item**:
    **Malisa Vucinic** to evaluate the use of FETCH in
    `draft-ietf-6tisch-minimal-security` and report to WG.
* _[14:11]_ (exp. 14:00) `draft-ietf-6tisch-terminology-10` (Thomas Watteyne,
on behalf of **Maria Rita Palattella**)
    * [**Thomas Watteyne**] 48 definitions in the terminology document. WG
* _[14:12]_ (exp. 14:02) `draft-ietf-6tisch-6top-sfx-01` (**Diego Dujovne**)
    * [**Diego Dujovne**] heritting from SF0. Editorial changes. Modifified
    command response list to answer 6P requirements. * SFX does not explicitly
    define a security system. * added section on SF identifier. * addressed
    comments from Lotte: allocation policy, using new feature by 6P, time
    measurement, number of cells to be added at boot * after publishing next
    version, request to WGLC * [**Pascal Thubert**] we'll take advice from the
    room and discuss with Suresh (AD) after this meeting
* _[14:17]_ (exp. 14:10) `draft-chang-6tisch-msf-01` (**Tengfei Chang**)
    * [**Tengfei Chang**] this draft is implemented in OpenWSN.
    * addressed comments:
        * what to do when unreachable?  MUST issue a 6P CLEAR and remove
        neighbor from neighbor table, * recalculating time out. * Which type
        packet to be sent in shared cell? * wording using "internet": "traffic
        from the internet" changed to "traffic from root"
    * draft is tested in simulation and testbed. Asking for WG adoption.
    * [**Pascal Thubert**] how many read the draft? "quite a large number".
    * [**Pascal Thubert**] who thinks ready for adoption? 7 hands
    * [**Christian Hopfner**] _(remote)_ supports adoption.
    * will confirm on the mailing list.
    > **Action item**: **Chairs** to confirm WG adoption of
    `draft-chang-6tisch-msf` on the ML.
* _[14:23]_ (exp. 14:20) `draft-duquennoy-6tisch-asf-01` (**Simon Duquennoy**)
    * Autonomous Scheduling Function. Using MAC address, nodes calculate the TS
    offset to communicate. * Presented ASF slotframe descriptor. *
    Configuration dissemination using EB. Secure IE in EB for ASF
    dissemination. * [**Malisa Vucinic**] by security, do you mean EB IE
    encrypted? * [**Malisa Vucinic**] we say pledge has to accept the key.
    Beacon is authenticated. * [**Malisa Vucinic**] cannot encrypt EBs, because
    they carry ASN in their payload. * added Burst mode, with consecutive
    slots. Transmission of data using IEEE802.15.4 frame pending bit. *
    [**Thomas Watteyne**] this works best when high PDR between the nodes? *
    [**Simon Duquennoy**] agreed * [**Thomas Watteyne**] ASF has a bunch of
    cool ideas.
        * hashed MAC address based rendez-vous cell
        * pending bit
    * [**Thomas Watteyne**] complementary to MSF. Idea to merge them together.
    Better than having two SFs side by side. * [**Thomas Watteyne**] should
    that be split into various documents, or just one? * [**Thomas Watteyne**]
    MSF and ASF working together may work better than each by itself. *
    [**Malisa Vucinic**] document the Pending bit use in a separate document? *
    [**Thomas Watteyne**] side discussion about how to use Pending bit. *
    [**Pascal Thubert**] this idea of a burst mode has been had before.
    Recommend to dig out materail from this discussion * [**Thomas Watteyne**]
    When using the Pending bit, next cell which channel offset? * [**Simon
    Duquennoy**] same channel offset > **Action item**: **Simon Duquennoy**
    to work with WG to integrate ideas of the `draft-duquennoy-6tisch-asf` into
    `draft-chang-6tisch-msf` (pending bit might be a different document)
* _[14:37]_ (exp. 14:30) `draft-vilajosana-6tisch-globaltime-00` (**Xavi
    * ASN is relative time marker, but not global across networks.
    * believe that global enable other functionalities, including security.
    * Main idea: distribute global time.
    * Question: do you think this is relevant to this WG?
    * Distribute mapping between ASN and absolute time. Also, optionally, an
    address for a time source, period for resynchronize, leap second. * leap
    second correction. * [**Carsten Bormann**] what is this link-format? *
    [**Xavi Vilajosana**] the URI of the resource to query at the server. *
    [**Thomas Watteyne**] update to contain recent ASN and associated global
    time, not just global time at ASN=0. Because of local clock drift. *
    [**Georgios Papadopoulos**] uses cases for this draft. Why global time? *
    [**Xavi Vilajosana**] in order to timestamp sensory data. If tagged with
    ASN, needs post-processing. * [**Thomas Watteyne**] more important is the
    reverse: want to sample at the same time from different sensor nodes that
    are on different networks. * They have to sample at the same absolute time.
    No post-processing possible. * [**Malisa Vucinic**] this is useful for
    verification. * [**Thomas Watteyne**] be sure from where you get the info
    from. Must be secured, e.g. JRC. * [**Malisa Vucinic**] looking at the CBOR
    structure. Get global time from JRC. What is the purpose of the optional
    parameter (address of time server)? * [**Pascal Thubert**] will carry on on
    the mailing list. Save time for other presentation * [**Thomas Watteyne**]
    I think this is very interesting, but since not in charter, too early for
    WG adoption. Let's gather interest from the WG, and if WG agrees, we can
    work to add to charter. > **Action item**: **Chairs** to assess
    consensus on whether there is interest to work on
    `draft-vilajosana-6tisch-globaltime`, and possibly add to the charter.
* _[14:50]_ (exp. 14:40)
`draft-richardson-6tisch-enrollment-enhanced-beacon-00` and
`draft-richardson-6tisch-roll-enrollment-priority-00` (**Michael Richardson**)
    * Situation is: beacons sent out by lots of nodes, a joining node needs to
    get an idea of which DODAG and join proxy to choose. * Issues: how to
    select network to try joining? * What is Join in the first place?
    enrollment * [**Malisa Vucinic**] don't agree with the enrollment term, may
    be misleading. Terminology to be discussed after. * [**Michael
    Richardson**] some want to select PAN based on some observed metric before
    having enrolled in any of them * [**Michael Richardson**] proxy resources
    may vary. New IE where can be seen the proxy priority. * [**Thomas
    Watteyne**] how are the 3 priorities used and managed? * [**Michael
    Richardson**] proxy priority. PAN priority. Rank priority. * [**Thomas
    Watteyne**] reserved space at the code lounge. Is it for this discussion? *
    [**Michael Richardson**] yes, at 4pm in the code lounge. To define new IE.
    * [**Michael Richardson**] tomorrow at ROLL, will discuss how to configure
    these priorities. > **Michael Richardson** to lead a discussion with the
    6TiSCH WG about precise use cases for
* _[15:00]_ (exp. 14:50) meeting ends