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Versions: 00 01 02 03 04 05 06                                          
DetNet                                                   P. Thubert, Ed.
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                             8 June 2021
Expires: 10 December 2021


                   IPv6 Hop-by-Hop Options for DetNet
                   draft-pthubert-detnet-ipv6-hbh-00

Abstract

   RFC 8938, the Deterministic Networking Data Plane Framework relies on
   the 6-tuple to identify an IPv6 flow.  But the full DetNet operations
   require also the capabilities to signal meta-information such as a
   sequence within that flow, and to transport different types of
   packets along the same path with the same treatment, e.g.,
   Operations, Administration, and Maintenance packets and/or multiple
   flows with fate and resource sharing.  This document introduces new
   Hop-by-Hop header option that can signal that information to the
   intermediate relays.

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 https://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 10 December 2021.

Copyright Notice

   Copyright (c) 2021 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 (https://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



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   extracted from this document must 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
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  The DetNet Options  . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Sequencing Option . . . . . . . . . . . . . . . . . . . .   4
     3.2.  RPL Packet Information  . . . . . . . . . . . . . . . . .   6
     3.3.  DetNet Local Path Option  . . . . . . . . . . . . . . . .   7
     3.4.  DetNet Global Path Option . . . . . . . . . . . . . . . .   7
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Section 2 of the Deterministic Networking Problem Statement
   [DetNet-PS] introduces the concept of Deterministic Networking
   (DetNet) to the IETF.  DetNet extends the reach of lower layer
   technologies such as Time-Sensitive Networking (TSN) [IEEE 802.1 TSN]
   and Timeslotted Channel Hopping (TSCH) [IEEE Std. 802.15.4] over IPv6
   and MPLS [RFC8938].

   The "Deterministic Networking Architecture" [DetNet-ARCHI] details
   the contribution of layer-3 protocols, and defines three planes: the
   Application (User) Plane, the Controller Plane, and the Network
   Plane.  [DetNet-ARCHI] places an emphasis on the centralized model
   whereby a controller instantiates per-flow state in the routers to
   perform adequate forwading operations so as to provide end-to-end
   reliability and bounded latency guarantees.














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   The "6TiSCH Architecture" [6TiSCH-ARCHI] leverages RPL, the "Routing
   Protocol for Low Power and Lossy Networks" [RFC6550] and introduces
   concept of a Track as a highly redundant RPL Destination Oriented
   Directed Acyclic Graph (DODAG) rooted at the Track Ingress node, that
   can be installed using so-called projected routes [RPL-PDAO].  In
   that case, the TrackId is an index from a namespace associated to one
   IPv6 address of the Track Ingress node, and the Track that an IPv6
   packet follows is signaled by the combination of the source address
   (of the Track Ingress node), and the TrackID placed in a RPL Option
   [RFC6553] located in an IPv6 Hop-by-Hop (HbH) Options Header [IPv6]
   in the IPv6 packet.

   The "Reliable and Available Wireless (RAW) Architecture/Framework"
   [RAW-ARCHI], extends the DetNet Network Plane to accomodate one or
   multiple hops of homogeneous or heterogeneous wireless technologies,
   e.g. a Wi-Fi6 Mesh or parallel radio access links combining Wi-Fi and
   5G.  The RAW Architecture reuses the concept of Track and introduces
   a new dataplane component, the Path Selection Engine (PSE), to
   dynamically select a subpath and maintain the required quality of
   service within a Track in the face of the rapid evolution of the
   medium properties.

   With [IPv6], the behavior of a router upon an IPv6 packet with a HbH
   Options Header has evolved, making the examination of the header by
   routers along the path optional, as opposed to previously mandatory.
   Additionally, the Option Type for any option in a HbH Options Header
   encodes in the leftmost bits whether a router that inspects the
   header should drop the packet or ignore the option when encountering
   an unknown option.  Combined, these capabilities enable a larger use
   of the header beyond the boundaries of a limited domain, as
   examplified by the change of behavior of the RPL data plane, that was
   changed to allow a packet with a RPL option to escape the RPL domain
   in the larger Internet [RFC9008].

   "IPv6 Hop-by-Hop Options Processing Procedures" [HbH-PROCESS] further
   specifies the procedures for how IPv6 Hop-by-Hop options are
   processed to make their processing even more practical and increase
   their use in the Internet.  In that context, it makes sense to
   consider the Hop-by-Hop Options to transport the information that is
   relevant to DetNet, making it independant of the transport and
   placing it early in the header chain.

   The "Deterministic Networking Data Plane Framework" [RFC8938]relies
   on the 6-tuple to identify an IPv6 flow.  But the full DetNet
   *operations require also the capabilities to signal meta-information
   such as a sequence within that flow, and to transport different types
   of packets along the same path with the same treatment.  For
   instance, it is required that Operations, Administration, and



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   Maintenance (OAM) [RFC6291] packets and/or multiple flows share the
   same fate and resource sharing over the same Track or the same
   Traffic Engineered (TE) [RFC3272] DetNet path.

   This document introduces new Hop-by-Hop options that can signal path
   and sequencing information to the intermediate relays early in the
   packet and independantly of the transport layer.

2.  Terminology

   Timestamp semantics and timestamp formats used in this document are
   defined in "Guidelines for Defining Packet Timestamps" [RFC8877].

   The Deterministic Networking terms used in this document are defined
   in the "Deterministic Networking Architecture" [DetNet-ARCHI].

   The terms Track and TrackID are defined in the "6TiSCH Architecture"
   [6TiSCH-ARCHI].

3.  The DetNet Options

   This document defines a number of IPv6 options to be placed in a HbH
   Options Header; the format of these options follow the generic
   definition in section 4.2 of [IPv6].

3.1.  Sequencing Option

   A typical packet sequence can be expressed uniquely as a wrapping
   counter, represented as an unsigned integer in the option.  In that
   case, the size of the representation MUST be large enough to cover
   several times the upper bound on out-of-order packet delivery in
   terms of number of packets.

   This specification also allows to use a time stamp for the packet
   sequencing following the recommendations in [RFC8877].  This can be
   accomplished by utilizing the Precision Time Protocol (PTP) format
   defined in IEEE Std. 1588 [IEEE Std. 1588] or Network Time Protocol
   (NTP) [RFC5905] formats.  In that case, the timestamp resolution at
   the node that builds the option MUST be fine enough to ensure that
   two consecutive packets are never stamped with the same value.

   This specification also allows for an hybrid model with a coarse
   grained packet sequence within a coarse grained time stamp.  In that
   case, both a time stamp option and a wrapping counter options are
   found, and the counter is used to compare packets with the same time
   stamp.





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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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Option Type  |  Opt Data Len |   Seq. Type   |    Reserved   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     .                                                               .
     .          Sequencing Information (variable Size)               .
     .                                                               .
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 1: Sequencing Option Format

   Sequencing Option fields:

   Option Type:  8-bit identifier of the type of option.  Value TBD by
      IANA.

   Sequence Type:  8-bit identifier of the type of sequencing
      information.  Value to be confirmed by IANA.






























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      +=======+============+===============+===========================+
      |  Seq. | Sequencing | Commin Name   | Sequencing                |
      |  Type | Type       |               | Information Format        |
      | Value |            |               |                           |
      +=======+============+===============+===========================+
      |   1   | Wrapping   | Basic         | 32-bit unsigned           |
      |       | Counter    | Sequence      | integer                   |
      |       |            | Counter       |                           |
      +-------+============+---------------+---------------------------+
      |   2   | Wrapping   | Zero-avoiding | 32-bit unsigned           |
      |       | Counter    | Sequence      | integer, wraps to 1       |
      |       |            | Counter       |                           |
      +-------+============+---------------+---------------------------+
      |   3   | Wrapping   | RPL Sequence  | 8-bit RPL sequence,       |
      |       | Counter    | Counter       | see section 7.  of        |
      |       |            |               | [RFC6550]                 |
      +-------+============+---------------+---------------------------+
      |   11  | Time Stamp | Fractional    | NTP 64-bit Timestamp      |
      |       |            | NTP           | Format, see section       |
      |       |            |               | 4.2.1.  of [RFC8877]      |
      +-------+============+---------------+---------------------------+
      |   12  | Time Stamp | Short NTP     | NTP 32-bit Timestamp      |
      |       |            |               | Format, see section       |
      |       |            |               | 4.2.2.  of [RFC8877]      |
      +-------+============+---------------+---------------------------+
      |   13  | Time Stamp | PTP           | PTP 80-bit Timestamp      |
      |       |            |               | Format, see [IEEE         |
      |       |            |               | Std. 1588]                |
      +-------+============+---------------+---------------------------+
      |   13  | Time Stamp | Short PTP     | PTP 64-bit Truncated      |
      |       |            |               | Timestamp Format,         |
      |       |            |               | see section 4.3. of       |
      |       |            |               | [RFC8877]                 |
      +-------+============+---------------+---------------------------+

                  Table 1: Sequence Type values (suggested)

3.2.  RPL Packet Information

   6TiSCH [6TiSCH-ARCHI] and RAW [RAW-ARCHI] signal a Track using a RPL
   Option [RFC6553] with a RPLInstanceID used as TrackID.  This
   specification reuses the RPL option as a method to signal a DetNet
   path.  In that case, the Projected-Route 'P' flag [RPL-PDAO] MUST be
   set to 1, and the O, R, F flags, as well as the Sender Rank field,
   MUST be set to 0 by the originator, forwarded as-is, and ignored on
   reception.





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3.3.  DetNet Local Path Option

   This specification also allows for an hybrid model with a coarse
   grained packet sequence within a coarse grained time stamp.  In that
   case, both a time stamp option and a wrapping counter options are
   found, and the counter is used to compare packets with the same time
   stamp.

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Option Type  |  Opt Data Len |    Local Path ID              |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 2: DetNet Local Path Option Format

   Sequencing Option fields:

   Option Type:  8-bit identifier of the type of option.  Value TBD by
      IANA.

   Opt Data Len:  8-bit length of the option data, set to 2.

   Local Path ID:  16-bit identifier of the DetNet Path, taken from a
      local namespace associated with the IPv6 source address of the
      packet.

3.4.  DetNet Global Path Option

   This specification also allows for an hybrid model with a coarse
   grained packet sequence within a coarse grained time stamp.  In that
   case, both a time stamp option and a wrapping counter options are
   found, and the counter is used to compare packets with the same time
   stamp.

      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  Option Type  |  Opt Data Len |   Origin Autonomous System    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          Global Path ID                       |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 3: DetNet Glocal Path Option Format

   Sequencing Option fields:

   Option Type:  8-bit identifier of the type of option.  Value TBD by



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      IANA.

   Opt Data Len:  8-bit length of the option data, set to 6.

   Origin Autonomous System:  16-bit identifier of the Autonomous
      Systems (AS) that originates the path.

   Global Path ID:  32-bit identifier of the DetNet Path, taken from a
      local namespace associated with the origin AS of the DetNet path.
      The value of 0 signals a DetNet path that is constrained within
      the local AS or the local administrative DetNet domain.

4.  Security Considerations

5.  IANA Considerations

   This document has no IANA actions.

6.  Acknowledgments

   TBD

7.  References

7.1.  Normative References

   [IPv6]     Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC8877]  Mizrahi, T., Fabini, J., and A. Morton, "Guidelines for
              Defining Packet Timestamps", RFC 8877,
              DOI 10.17487/RFC8877, September 2020,
              <https://www.rfc-editor.org/info/rfc8877>.

   [HbH-PROCESS]
              Hinden, R. M. and G. Fairhurst, "IPv6 Hop-by-Hop Options
              Processing Procedures", Work in Progress, Internet-Draft,
              draft-hinden-6man-hbh-processing-00, 3 December 2020,
              <https://tools.ietf.org/html/draft-hinden-6man-hbh-
              processing-00>.

   [DetNet-ARCHI]
              Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", RFC 8655,
              DOI 10.17487/RFC8655, October 2019,
              <https://www.rfc-editor.org/info/rfc8655>.



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7.2.  Informative References

   [RPL-PDAO] Thubert, P., Jadhav, R. A., and M. Gillmore, "Root
              initiated routing state in RPL", Work in Progress,
              Internet-Draft, draft-ietf-roll-dao-projection-16, 15
              January 2021, <https://tools.ietf.org/html/draft-ietf-
              roll-dao-projection-16>.

   [RAW-ARCHI]
              Thubert, P., Papadopoulos, G. Z., and R. Buddenberg,
              "Reliable and Available Wireless Architecture/Framework",
              Work in Progress, Internet-Draft, draft-pthubert-raw-
              architecture-05, 15 November 2020,
              <https://tools.ietf.org/html/draft-pthubert-raw-
              architecture-05>.

   [RFC6291]  Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
              D., and S. Mansfield, "Guidelines for the Use of the "OAM"
              Acronym in the IETF", BCP 161, RFC 6291,
              DOI 10.17487/RFC6291, June 2011,
              <https://www.rfc-editor.org/info/rfc6291>.

   [RFC5905]  Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
              "Network Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
              <https://www.rfc-editor.org/info/rfc5905>.

   [RFC6550]  Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
              Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
              JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
              Low-Power and Lossy Networks", RFC 6550,
              DOI 10.17487/RFC6550, March 2012,
              <https://www.rfc-editor.org/info/rfc6550>.

   [RFC6553]  Hui, J. and JP. Vasseur, "The Routing Protocol for Low-
              Power and Lossy Networks (RPL) Option for Carrying RPL
              Information in Data-Plane Datagrams", RFC 6553,
              DOI 10.17487/RFC6553, March 2012,
              <https://www.rfc-editor.org/info/rfc6553>.

   [DetNet-PS]
              Finn, N. and P. Thubert, "Deterministic Networking Problem
              Statement", RFC 8557, DOI 10.17487/RFC8557, May 2019,
              <https://www.rfc-editor.org/info/rfc8557>.







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   [RFC9008]  Robles, M.I., Richardson, M., and P. Thubert, "Using RPI
              Option Type, Routing Header for Source Routes, and IPv6-
              in-IPv6 Encapsulation in the RPL Data Plane", RFC 9008,
              DOI 10.17487/RFC9008, April 2021,
              <https://www.rfc-editor.org/info/rfc9008>.

   [6TiSCH-ARCHI]
              Thubert, P., Ed., "An Architecture for IPv6 over the Time-
              Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)",
              RFC 9030, DOI 10.17487/RFC9030, May 2021,
              <https://www.rfc-editor.org/info/rfc9030>.

   [RFC3272]  Awduche, D., Chiu, A., Elwalid, A., Widjaja, I., and X.
              Xiao, "Overview and Principles of Internet Traffic
              Engineering", RFC 3272, DOI 10.17487/RFC3272, May 2002,
              <https://www.rfc-editor.org/info/rfc3272>.

   [RFC8938]  Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
              Bryant, "Deterministic Networking (DetNet) Data Plane
              Framework", RFC 8938, DOI 10.17487/RFC8938, November 2020,
              <https://www.rfc-editor.org/info/rfc8938>.

   [IEEE Std. 802.15.4]
              IEEE standard for Information Technology, "IEEE Std.
              802.15.4, Part. 15.4: Wireless Medium Access Control (MAC)
              and Physical Layer (PHY) Specifications for Low-Rate
              Wireless Personal Area Networks".

   [IEEE 802.1 TSN]
              IEEE 802.1, "Time-Sensitive Networking (TSN) Task Group",
              <http://www.ieee802.org/1/pages/tsn.html>.

   [IEEE Std. 1588]
              IEEE, "IEEE Standard for a Precision Clock Synchronization
              Protocol for Networked Measurement and Control Systems",
              IEEE Standard 1588,
              <https://ieeexplore.ieee.org/document/4579760/>.

Author's Address

   Pascal Thubert (editor)
   Cisco Systems, Inc
   France

   Phone: +33 497 23 26 34
   Email: pthubert@cisco.com





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