Re: [6tisch] [6lo] Thomas' review of draft-richardson-6lo-ra-in-ie-00

[sajjad akbar <[e-mail]>]

Hi

As per my research experiments if we consider patient monitoring, I found TSCH
is considered as a new efficient MAC protocol that incorporates
time-slotted access with multiple channel and channel hopping. It is
popular mainly due to its interoperability with Internet of things (IoTs)
with appropriate support to mesh networks.  As TSCH more suitable for high
coverage scenarios and particularly node-coordinator scenarios like patient
monitoring systems are ignored, however slotted CSMA/CA proved to be more
efficient for patient monitoring. What you guys think?

Regards
Sajjad

On Mon, Nov 21, 2016 at 1:13 PM, Thomas Watteyne <[e-mail]>
wrote:

> Michael, all,
>
> Please find below my review of draft-richardson-6lo-ra-in-ie-00.
> Since interesting for both 6lo and 6TISCH, sending to both MLs.
>
> Typos fixed directly in line (please use diff), discussion points started
> at newline with "TW>" prefix.
>
> Since short draft, send review in body directly.
>
> Thomas
>
> ====
>
> 6lo Working Group                                          M. Richardson
> Internet-Draft                                  Sandelman Software Works
> Intended status: Informational                          October 18, 2016
> Expires: April 21, 2017
>
>
>      802.15.4 Informational Element encapsulation of ICMPv6 Router
>                              Advertisements
>                     draft-richardson-6lo-ra-in-ie-00
>
> Abstract
>
>    In TSCH mode of 802.15.4, as described by [I-D.ietf-6tisch-minimal],
> TW> I would suggest to use "IEEE802.15.4" everywhere, just to be ultra
> clear
>    opportunities for broadcasts are limited to specific times and
>    specific channels.  An enhanced beacon must be broadcast periodically
>    by every router to keep all nodes in sync.
> TW> I would rephrase the last sentence to "Nodes in a TSCH network
> typically frequently send Enhanced Beacon (EB) frames to announce the
> presence of the network"
>    This document provides a
>    mechanism by which other small ICMPv6 packets, such as Router
>    Advertisements may be carried within the Enhanced Beacon,
> TW> why not simply talk about RAs rather than "other small... such as..."
>    providing
>    standard IPv6 router/host protocol.
> TW> "providing standard IPv6 router/host protocol." word missing?
>
> Status of This Memo
>
>    This Internet-Draft is submitted in full conformance with the
>    provisions of BCP 78 and BCP 79.
>
>    Internet-Drafts are working documents of the Internet Engineering
>    Task Force (IETF).  Note that other groups may also distribute
>    working documents as Internet-Drafts.  The list of current Internet-
>    Drafts is at http://datatracker.ietf.org/drafts/current/.
>
>    Internet-Drafts are draft documents valid for a maximum of six months
>    and may be updated, replaced, or obsoleted by other documents at any
>    time.  It is inappropriate to use Internet-Drafts as reference
>    material or to cite them other than as "work in progress."
>
>    This Internet-Draft will expire on April 21, 2017.
>
> Copyright Notice
>
>    Copyright (c) 2016 IETF Trust and the persons identified as the
>    document authors.  All rights reserved.
>
>    This document is subject to BCP 78 and the IETF Trust's Legal
>    Provisions Relating to IETF Documents
>    (http://trustee.ietf.org/license-info) in effect on the date of
>    publication of this document.  Please review these documents
>    carefully, as they describe your rights and restrictions with respect
>    to this document.  Code Components extracted from this document must
>
>
>
> Richardson               Expires April 21, 2017                 [Page 1]
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>
>
>    include Simplified BSD License text as described in Section 4.e of
>    the Trust Legal Provisions and are provided without warranty as
>    described in the Simplified BSD License.
>
> Table of Contents
>
>    1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
>      1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
>      1.2.  Layer-2 Synchronization . . . . . . . . . . . . . . . . .   2
>      1.3.  Layer-3 synchronization IPv6 Router solicitations and
>            advertisements  . . . . . . . . . . . . . . . . . . . . .   3
>    2.  Protocol Definition . . . . . . . . . . . . . . . . . . . . .   3
>      2.1.  Protocol Example  . . . . . . . . . . . . . . . . . . . .   4
>    3.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
>    4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
>    5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
>      5.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
>      5.2.  Informative References  . . . . . . . . . . . . . . . . .   8
>    Appendix A.  appendix . . . . . . . . . . . . . . . . . . . . . .   8
>    Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9
>
> 1.  Introduction
>
>    [I-D.ietf-6tisch-architecture] describes the use of the time-slotted
>    channel hopping (TSCH) mode of [ieee802154].
> TW> I would cite RFC7554 instead, which specifically describes TSCH
>    As further detailed in
>    [I-D.ietf-6tisch-minimal], an Extended Beacon is transmitted during a
>    slot designated as broadcast slot.
>
>    EDNOTE: Explain why broadcasts are rare, and why we need them.  What
>    the Enhanced Beacon is, and what Information Elements are, and how
>    the IETF has a subtype for that area.  Explain what kind of things
>    could be placed in Information Elements, how big they could be, and
>    how they could be compressed.
>
> 1.1.  Terminology
>
>    In this document, the key words "MUST", "MUST NOT", "REQUIRED",
>    "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
>    and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119
>    [RFC2119] and indicate requirement levels for compliant STuPiD
>    implementations.
>
> 1.2.  Layer-2 Synchronization
>
>    As explained in Section 6 of [I-D.ietf-6tisch-minimal], the Enhanced
>    Beacon has a number of purposes: synchronization of ASN and Join
>    Metric, timeslot template identifier, channel hopping sequence
>    identifier, container for minimal slotframe/cell configuration.
>
>
>
> Richardson               Expires April 21, 2017                 [Page 2]
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>
> TW> I have completely rewritten the paragraph below
> The Enhanced Beacon (EB) is used by nodes already part of a TSCH network
> to annouce its existance.
> Receiving an EB allows a Joining Node (pledge) to learn about the network
> and synchronize to it.
> The EB may also be used as a means for a node already part of the network
> to re-synchronize [RFC7554].
>
> EBs are sent on broadcast slots.
>    There are a limited number of timeslots designated as a broadcast
>    slot by each router.  These slots are rare, and with 10ms slots and
>    a slotframe length of 100 slots, there may be as little as 1 slot per
> second
>    available to send the EB on.
>
> 1.3.  Layer-3 synchronization IPv6 Router Solicitations and
>       Advertisements
>
>    At layer 3, [RFC2461] defines a mechanism by which nodes learn about
>    routers by listening for multicast Router Advertisements (RA).  If
>    no RA is heard within a set time, a Router Solicitation (RS) may
>    be multicast, to which an RA will be received, usually unicast.
>
>    Although [RFC6775] reduces the amount of multicast necessary to do
>    address resolution via Neighbor Solicitation messages, it still
>    requires multicast of either RAs or RSs.  This is an expensive
>    operation for two reasons: in the TSCH context, there are few multicast
> timeslots for
>    unsolicited RAs; if a pledge node does not hear an RA, and decides to
>    send a RS (consuming a broadcast aloha slot with unencrypted
>    traffic), many unicast RS may be sent in response.
>
>    This is a particularly acute issue for the 6TiSCH join process for the
>    following reasons:
>
>    1.  Use of a multicast slot by even a non-malicious unauthenticated
>        node for a Router Solicitation may overwhelm that time slot.
>
>    2.  It may require many seconds of on-time before a new pledge hears
>        a Router Solicitation it can use.
>
>    3.  A new pledge may listen to many Enhanced Beacons before it can
>        pick an appropriate network and/or closest Join Assistant to
>        attach to.  If it must listen for a RS as well as find the
>        Enhanced Beacon, then the process may take a very long time.
>
> 2.  Protocol Definition
>
>    [I-D.kivinen-802-15-ie] creates a registry for new IETF IE subtypes.
>    This document allocates a new subtype TBD-XXX.
>
>
>
>
>
>
> Richardson               Expires April 21, 2017                 [Page 3]
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>
>
>    The base IE subtype structure is as follows.  As explained in
>    [I-D.kivinen-802-15-ie] the length of the Sub-Type Content can be
>    calculated.
>
>                         1                   2                   3
>     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |   TBD-XXX     |       6LoRH encoded structure                 |
>    +-+-+-+-+-+-+-+-+                                               |
>    ~                       Sub-Type Content                        ~
>    |                                                               |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>
> TW> I'm missing some text here which explains what is being proposed.
> TW> It's clear at this point what IEs and RAs are, and I was expecting
> some text which says, basically
> TW> "and we want to transport RAs in IEs, in some compressed format, and
> here is the proposed format"
> TW> The remainder of my remarks relate to this: I'm a confused at this
> point of the reading what it is you are trying to accomplish.
>
>    Inside the Sub-Type content should be placed compressed packets
>    according to [RFC6282] (as updated by
>    [I-D.ietf-6lo-dispatch-iana-registry].
>
> 2.1.  Protocol Example
>
> TW> I assume that by "Typically", you mean "in the unconstrained IPv6 case"
>    Typically, a Router Advertisement is placed inside the Sub-Type.
> TW> Sub-Type of what?
>    The entire structure typically looks like:
>
>
>
>
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>
>     0                   1                   2                   3
>     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |Ver  6 | TC = 0        |           Flow Label = 0              |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |         Payload Length        |  NH = 58      | Hop Lmt = 1   |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |                                                               |
>    +                                                               +
>    |                                                               |
>    +                         Source Address                        +
>    |                           fe80::LL                            |
>    +                                                               +
>    |                                                               |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |                                                               |
>    +                                                               +
>    |                                                               |
>    +                      Destination Address                      +
>    |                           fe02::1                             |
>    +                                                               +
>    |                                                               |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |  Type = 134   |  Code = 0     |          Checksum             |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    | HL = 0        |0|0|  Reserved |  Router lifetime = 9000       |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |                         Reachable Time   = 0  XXX             |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |                          Retrans Timer   = 0  XXX             |
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    | Type = 1      | Len = 10      |    EUI-64 of router           |
>    +-+-+-+-+-+-+-+-+-+-+-+---------+                               +
>    |                    EUI-64 of router                           |
>    +                               +---------------+---------------+
>    | EUI-64 of router              | Type = TBD-YYY|  Len = 18     |
>    +-------------------------------+-------------------------------+
>    |                             DODAGID                           |
>    +                                                               |
>    |                                                               |
>    +                                                               |
>    |                                                               |
>    +                                                               |
>    |                                                               |
>    +---------------------------------------------------------------+
>
> TW> Not clear at this point what IPv6 Neighbor Discovery Option TBD-YYY
> refers to
>
>    When compressed by [RFC6282], this becomes:
>
>
>
>
> Richardson               Expires April 21, 2017                 [Page 5]
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>
>    +---------------------------------------------------------------+
>    | 0 | 1 | 1 |TF= 11 |NH |HLIM=01|CID|SAC|  SAM  | M |DAC|  DAM  | 0
>    +   |   |   |       | 0 |       | 0 | 0 | 0   1 + 1 + 0 + 1   1 +
>    +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
>    | NH = 0x58                     |   dstXX = 0x01                | 4
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |  Type = 134   |  Code = 0     |          Checksum             | 8
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    | HL = 0        |0|0|  Reserved |  Router lifetime = 9000       | 12
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |                         Reachable Time   = 0  XXX             | 16
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    |                          Retrans Timer   = 0  XXX             | 20
>    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>    | Type = 1      | Len = 10      |    EUI-64 of router           | 24
>    +-+-+-+-+-+-+-+-+-+-+-+---------+                               +
>    |                    EUI-64 of router                           | 28
>    +                               +---------------+---------------+
>    | EUI-64 of router              | Type = TBD-YYY|  Len = 18     | 32
>    +-------------------------------+-------------------------------+
>    |                             DODAGID                           | 36
>    +                                                               |
>    |                                                               | 40
>    +                                                               |
>    |                                                               | 44
>    +                                                               |
>    |                                                               | 48
>    +---------------------------------------------------------------+
>
> TW> but this is simply the 4944/6282 compression of it, right? I don't see
> any IEs here.
>
>    The total number of bytes needed is 56 bytes.
>
> 3.  Security Considerations
>
>    TBD.
>
> 4.  IANA Considerations
>
>    Allocate a new number TBD-XXX from Registry IETF IE Sub-type ID.
>    This entry should be called 6LoRH-in-IE.
> TW> 6LoRH-in-IE or RA-in-IE?
>
>    Allocate a new number TBD-YYY from Neighbor Discovery Option Types
>    (RFC2461) with the name   "Constrained Network Identification".
> TW> not sure what this refers to
>
> 5.  References
>
>
>
>
>
>
>
> Richardson               Expires April 21, 2017                 [Page 6]
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>
> 5.1.  Normative References
>
>    [I-D.ietf-6lo-dispatch-iana-registry]
>               Chakrabarti, S., Montenegro, G., Droms, R., and j.
>               woodyatt, "6lowpan ESC Dispatch Code Points and
>               Guidelines", draft-ietf-6lo-dispatch-iana-registry-05
>               (work in progress), September 2016.
>
>    [I-D.ietf-6tisch-architecture]
>               Thubert, P., "An Architecture for IPv6 over the TSCH mode
>               of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work
>               in progress), June 2016.
>
>    [I-D.ietf-6tisch-minimal]
>               Vilajosana, X. and K. Pister, "Minimal 6TiSCH
>               Configuration", draft-ietf-6tisch-minimal-16 (work in
>               progress), June 2016.
>
>    [I-D.kivinen-802-15-ie]
>               Kivinen, T. and P. Kinney, "IEEE 802.15.4 Information
>               Element for IETF", draft-kivinen-802-15-ie-03 (work in
>               progress), October 2016.
>
>    [ieee802154]
>               IEEE Standard, ., "802.15.4-2015 - IEEE Standard for Low-
>               Rate Wireless Personal Area Networks (WPANs)", 2015,
>               <http://standards.ieee.org/findstds/
>               standard/802.15.4-2015.html>.
>
>    [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
>               Requirement Levels", BCP 14, RFC 2119,
>               DOI 10.17487/RFC2119, March 1997,
>               <http://www.rfc-editor.org/info/rfc2119>.
>
>    [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor
>               Discovery for IP Version 6 (IPv6)", RFC 2461,
>               DOI 10.17487/RFC2461, December 1998,
>               <http://www.rfc-editor.org/info/rfc2461>.
>
>    [RFC6282]  Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
>               Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
>               DOI 10.17487/RFC6282, September 2011,
>               <http://www.rfc-editor.org/info/rfc6282>.
>
>
>
>
>
>
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>
> Richardson               Expires April 21, 2017                 [Page 7]
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>    [RFC6775]  Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
>               Bormann, "Neighbor Discovery Optimization for IPv6 over
>               Low-Power Wireless Personal Area Networks (6LoWPANs)",
>               RFC 6775, DOI 10.17487/RFC6775, November 2012,
>               <http://www.rfc-editor.org/info/rfc6775>.
>
>    [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
>               Constrained-Node Networks", RFC 7228,
>               DOI 10.17487/RFC7228, May 2014,
>               <http://www.rfc-editor.org/info/rfc7228>.
>
> 5.2.  Informative References
>
>    [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
>               (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
>               December 1998, <http://www.rfc-editor.org/info/rfc2460>.
>
>    [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
>               More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
>               November 2005, <http://www.rfc-editor.org/info/rfc4191>.
>
>    [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
>               Control Message Protocol (ICMPv6) for the Internet
>               Protocol Version 6 (IPv6) Specification", RFC 4443,
>               DOI 10.17487/RFC4443, March 2006,
>               <http://www.rfc-editor.org/info/rfc4443>.
>
>    [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
>               Element (PCE)-Based Architecture", RFC 4655,
>               DOI 10.17487/RFC4655, August 2006,
>               <http://www.rfc-editor.org/info/rfc4655>.
>
>    [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
>               "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
>               DOI 10.17487/RFC4861, September 2007,
>               <http://www.rfc-editor.org/info/rfc4861>.
>
>    [RFC7554]  Watteyne, T., Ed., Palattella, M., and L. Grieco, "Using
>               IEEE 802.15.4e Time-Slotted Channel Hopping (TSCH) in the
>               Internet of Things (IoT): Problem Statement", RFC 7554,
>               DOI 10.17487/RFC7554, May 2015,
>               <http://www.rfc-editor.org/info/rfc7554>.
>
> Appendix A.  appendix
>
>    insert appendix here
>
>
>
>
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> Author's Address
>
>    Michael Richardson
>    Sandelman Software Works
>
>    Email: [e-mail]
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