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6lo Status Pages

IPv6 over Networks of Resource-constrained Nodes (Active WG)
Int Area: Éric Vyncke, Suresh Krishnan | 2014-Jun-10 —  

IETF-104 6lo minutes

Session 2019-03-25 1350-1550: Karlin 1/2 - Audio stream - 6lo chatroom


minutes-104-6lo-01 minutes - Chairs: Shwetha Bhandari, Carles Gomez Responsible AD: Suresh Krishnan

          6lo WG Agenda - IETF 104, Prague
                13:50-15:50 @Karlin 1/2
                Monday, March 25, 2019
                Chairs: Shwetha Bhandari, Carles Gomez
                Responsible AD: Suresh Krishnan
                Minute takers: Dominique Barthel, Antoine BERNARD
                Jabber scribe: Rahul Jadhav
                Meetecho for remote participants:
                Etherpad for notes:
          AGENDA (see live meeting notes below the agenda)
            Introduction and draft status
            Bhandari/Gomez            10 min
            Agenda bashing; blue sheets; scribe; Jabber scribe
            Status of WGLC - Address Protected ND
            10 min
            Status and Publication Request of Backbone Router            Pascal
            Thubert             5 min
            ND Unicast Lookup - WG adoption
            10 min
            6LoWPAN packet delivery deadline time: Last changes          Charlie
            Perkins           15 min
            Update after WGLC and discussion on next steps               Yong-Geun
            Hong            10 min
            Update after WGLC of IPv6 Mesh over BLE networks             Carles
            Gomez              10 min
            Preparation for WGLC for LLN Minimal Fragment Forwarding     Thomas
            Watteyne           10 min
            Status of Fragment Recovery                                  Pascal
            Thubert            10 min
            Status of Transmission of IPv6 Packets over PLC Networks     Remy
            Liubing               5 min
          Total: 95 min
          [13:51] meeting starts
          [13:51] intro (chairs)
            * New chairs thank Gabriel and Samita, out-going chairs, for their work
            * Blue sheets, Note Well.
            * Agenda is shown. No comments on the agenda. Chairs propose to add
            one item, 6lo Wiki. No objection.
            * Suresh: NFC doc went through IESG evaluation, lot of stuff to address
            there, do authors want to add details?
            * Y. Choi: had telechat with IESG. Would like to thank all reviewers
            at IESG. Will address comments and produce updated draft.
            * Suresh: comment that some parts looked like "marketing text", can
            provide help to tone it down.
            * Suresh (on Jabber): one of the issues was that the technology related
            text was very marketing-oriented.
            * Y. Choi: will address that
          New RFC (RFC 8505) since the last meeting, congratulations to the authors
          9 drafts updated since the last IETF
          Packet Delivery Deadline Time draft submitted, some reviews from various
          directorates, the comments were taken into account and a new draft was
          WGLC ended on a few documents. Will be discussed today.
          Minimal fragment forwarding document believed to be ready for WGLC by
          the authors.
          Fragment Recovery and IPv6 over PLC in progress.
          [14:00]   Status of WGLC - Address Protected Neighbor Discovery (Pascal
            * Bunch called "Wireless ND" by Pascal.
            * Consist of series of 4 drafts that focus on ND.
            * A series of expections between IETF and IEEE that were never met :
                * Multicast is not reliable because it is not acknowledged, and
                also often slower, uses bandwidth.
                * IEEE expected from the IETF that proxy ND would be done at the
                access point.
            * Proposal is to register node address at Border Router.
            * Slide IPv6 and 802.11 : Text of the current specification for Proxy
            Neighbor Discovery as proposed by the IEEE.
            * Proposing new text for 802.11 main spec, including quote to RFC8505.
            * The text now explains the reasons why neighbor discovery and backbone
            router specification are necessary
            * Summary on RFC8505: message sequence diagram shown. Multicast kept
            to a minimum (first RS from node)
            * The registration is done sending an NS (with EARO option) message,
            changes to the address registration process.
            * First address registration includes a TID (similar to a public key)
            that will prove ownership for later registration attempts. It used to
            be the MAC address, a new process was proposed for security reasons.
            * Address Protection ND based on a first time first serve based
            ownership .
            * Address Protected ND has 3 crypto modes.
            * 6LR will challenge the joining 6LN to prove its authenticity when
            joining for the first time.
            * This required ROVR (Registration Ownership Verifier) option field,
            variable length.
            * René added some text in the security section.
            * Shwetha : The draft has already passed last call and received no
            reviews. What is the opinion of the people in the room considering
            the WG Last Call ended on March 16 ?
            * Pascal: got early SecDir review.
            * Shwetha: no disagreement in the room to proceed. Will do shephard
          [14:16] Status and Publication Request of Backbone Router (Pascal
            * Layer 3 access point, proxy neighbor discovery made by the backbone
            * Started since the start of the work on RFC6775 and split out of it
            during the work on it.
            * Resurected 2/3 years ago.
            * Pascal: Didn't go to 6man or INT on it, but would be happy to get
            * 6BBR transforms proactive unicast registration from 6LN/6BR to DAD
            over the backbone.
            * Looking for destination results in NS lookup in broadcast.
            * Bridge and proxy router mode available (depending on the link between
            6BBR and 6LBR)
          [14:20] ND Unicast Lookup - WG adoption (Pascal Thubert)
            * Matches a lot of proprietary implementations behavior.
            * Makes it standard.
            * We want to install 6LBR on the backbone that knows which address
            was registered by whom.
            * Created a new address mapping message, re-using the existing EDAR
            message type of ICMP, but defining a new code value inside the type.
            * lookup is now unicast as well.
            * Pascal goes through new message sequence diagram. Can now do unicast
            EDAR/ADAC to the registar on the backbone.
            * The big benefit of having a BBR on the backbone, you can use multicast
            only (but you can also fall back on the legacy system if you need it).
            * Pascal would like to get reviews.
            * Shwetha: volunteers? Rahul, Charlie. You can even cross post it in
            6man, this might have a more generic applicability.
            * Yes, it is designed for Wi-Fi but can be useful for other networks.
            * Charlie Perkins: would be unusual to adopt a draft if very few people
            have read it
            * Pascal: Not calling for adoption. Asking for reviews.
            * Carles: Thanks to Rahul and Charlie. Please post your reviews on
            the mailing list. I will try to do the same.
            * Pascal: And yes, once I have reviews and once they are addressed,
            I will probably ask for rapid adoption because this draft is behind
            the others.
            * Suresh: Remind Pascal of the efficient-nd draft at 6man a few years
            back (with Eric and Samita), faced opposition. Why would this one be
            * Pascal : I have been thinking about it. Pascal proposes to talk
            about it with Suresh the next time they meet.
          [14:30] 6LoWPAN packet delivery deadline time: Last changes (Charlie
            * Gone through WGLC, went to IESG, got many comments from directorates
            * -04 addressed these.
            * Assumes that devices are time synchronized.
            * Draft history and thanks to reviewers.
            * Discussion about multiple ways of representing the same time. Also,
            how do you know what is T0. Pretty ok for the time unit, though.
            * New draft addresses the T0 issue.
            * Suggestion by reviewer to use NTP time representation. NTP actually
            has 2 representations. New draft uses these, with added scaling factor
            to save bits.
            * One of the reviewers pointed out that instead of sending a complete
            time it would be better to send a delta encoding of the Origination Time
            (related to the Deadline Time), in order to save bits.
            * Binary point representation instead of Exponent, given the variety
            of representations now allowed.
            * Quite a lot of new additions due to addition of Synchronization to
            the draft.
            * New Format presentation.
            * Charlie: Will solicit new feedback for the latest version.
            * Pascal: forwarding based on this option should be drop or no
            drop. Anything else, more subtle.
            * Charlie: you're taking about the D bit.
            * Pascal: what about Quality of Service decision?
            * Charlie: If you want to expand, we would thank any review.
            * Shwetha: this draft is about deadline time. Pascal, other uses could
            go in separate draft.
            * Pascal: works.
            * Suresh: This hex digit is misleading, use nibbles instead.
            * Charlie: I was told that hex digit was better, but no problem to
            use nibbles.
          [14:45] Update after WGLC and discussion on next steps (Yong-Geun Hong)
            * Co-authors are each experts in different 6lo technologies.
            * This document is 2 1/2 years old. Purpose is to help newcomers
            understand how to use 6lo over various technologies.
            * May not be interesting to 6lo experts but has some real potential
            for future adopters.
            * WGLC was done in late 2018, but no comment was received. Maybe
            because it is very good!
            * Updated anyway to include PLC, and reflect advances in various
            documents referenced by this one.
            * 4 6lo scenarios.
            * HomePlug Alliance has stopped operating, rumored to transfer its
            standardization activity to Wi-SUN, but no official announcement.
            * Shwetha: living document. Should be published as an Informational
            document, or keep it in the 6lo Wiki?
            * Yong-Geun: what is the 6lo Wiki?
            * Carles: Place where different resources about the working group can
            be found: https://trac.ietf.org/trac/6lo
            * YGH: could be. Would still like to uprade doc with expert comments.
            * Pascal: What do we expect from 6lo in the future, would be cool to
            keep the document open.
            * Carles (as a co-author): would like to know how to interpret the
            silence during WGLC.
            * Shwetha: what does Suresh think?
            * Suresh: Not sure about the archival value of the draft, and also
            about the scope of the draft. If we decide to go for publication we
            will probably need to chop down a bit of it.
            * YGH: point taken. Will discuss with co-authors. Will considering
            narrowing down the scope.
          [14:52] Update after WGLC of IPv6 Mesh over BLE networks (Carles Gomez)
            * WGLC on -04, comments received, -05 released addressing those
            * Therefore authors believe doc is ready for next step.
            * Going through list of updates:
              - Terminology consistency
              - Not sure if doc is sufficient by itself to build a mesh over
              BTLE. Now made clear that it is not enough, e.g. does not define
              - Fragmentation was not explicitly addressed, it is now with BTLE4.2
              uses L2CAP fragmentation
              - Now refers to RFC8505 regarding ND. Discusses use of crypto
              addresses, protected ND...
              - Updated the security consideration part in the draft or by
              referencing other drafts (such as 6lo-ap-nd)
            * Questions?
            * Shwetha: does it address all reviewers’ comments? Nodding in the
          [14:59] Preparation for WGLC for LLN Minimal Fragment Forwarding (Thomas
            * Thomas reviews RFC4944 fragmentation, explains why per-hop F/R is
              - Latency
              - Memory constraint
            * Proposition to use fragment forwarding, will send the data without
            reassembling until the destination.
            * To describe that solution, 2 drafts at 6lo WG (minimal FF, frag
            recovery), 1 at lwig WG (virtual reassembly).
            * Minimal FF draft posted recently as an Informational draft to present
            the problem and the solution that is to be adopted.
            * Shows simulation results (simulation by Yatch on 6TiSCH simulator),
            which highlight the problem and the effectiveness of the solution.
             - the solution proposed reduces the memory usage and prevents packet
            * Believe draft is stable, asking about WGLC?
            * Carles: comments on this document? None heard.
            * Carles: will open WGLC, volunteers? George, Dominique
          [15:07] Status of Fragment Recovery (Pascal Thubert)
            * Thanks to Thomas for the introduction, will present the complementary
            work of the previous presentation.
            * Minimal FF does not address classical case of one lost
            fragment. Reassembly buffer blocked.
            * This draft about recovering the missing fragment(s). Similar to SCHC
            * You send the fragment, you receive an Ack bitmap that indicates
            which fragments were lost.
            * Cannot use RFC4944 format, defined new one.
            * With Flow Control, ECN, etc.
            * Implementations provided comments. Format did not allow for very
            large frames.
            * Format modification to reduce the size of the datagram tags,
            bits saved for datagram size field, therefore allows for large
            datagrams. (15.4g has 2 KiB frames.)
            * 6LoWPAN compression might change size of packet, had to include
            slack to allow for change in size on retransmission depending on the
            capacities of the devices that handle the packet.
            * Need to change the way a packet is handled without changing it
            depending on if you are the sender, the receiver or an intermediary.
            * Pascal: implementers are happy. Ready for WGLC?
            * Laurent: why not use SCHC meachanism instead?
            * Pascal: because this existed before SCHC.
            * Pascal: Would love to have reviews from the SCHC authors. One
            difference is that SCHC does not handle multiple hop retransmission.
            * Carles and Laurent to review before asking for WGLC.
          [15:15] Status of Transmission of IPv6 Packets over PLC Networks (Remy
            * Reviews history of this draft. Originally written by Huawei.
            * PLC used for more applications than metering. To control traffic
            lights, etc.
            * New uses now need Layer3.
            * G.9903, P1901.1 and P1902 are in scope of ths draft.
            * Was adopted and re-submitted as WG draft.
            * Not received a lot of comments, only 1 by Carsten, relating to
            confusing PLC landscape description. Description includes wide range
            of PLC technologies.
            * Added some clarification following this comment, that this draft
            focuses on constrained PLC.
            * Future work will add more references to header compression RFCs.
            * Feedback is requested.
            * Carles: are you aware of any implementations?
            * Remy: Some implementation exist.
            * Carles: It would be good to use these implementations as a work base
            to improve the specification.
          [15:21] 6lo Wiki (Carles as chair)
            * Requests that useful information is provided to populate the wiki.
            * Useful information includes open source implementations, interop
            events, etc.
          [15:22] Any other business?
          [15:22] Meeting adjourns

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