Internet DRAFT - draft-yzz-detnet-enhanced-data-plane

draft-yzz-detnet-enhanced-data-plane







DetNet                                                           X. Geng
Internet-Draft                                                   T. Zhou
Intended status: Standards Track                                L. Zhang
Expires: 25 April 2024                                            Huawei
                                                                   Z. Du
                                                            China Mobile
                                                         23 October 2023


                       DetNet Enhanced Data Plane
                draft-yzz-detnet-enhanced-data-plane-03

Abstract

   Aiming at providing the bounded latency to DetNet services, DetNet
   data plane is required to be enhanced.  This document provides a
   method to extend DetNet data plane by introducing the Bounded Latency
   Information (BLI), which facilitates DetNet transit nodes to
   guarantee the bounded latency transmission in data plane.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in .

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 25 April 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   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
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and Conventions . . . . . . . . . . . . . . . . .   4
     2.1.  Requirement Language  . . . . . . . . . . . . . . . . . .   4
     2.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Design of DetNet Enhanced Data Plane  . . . . . . . . . . . .   5
     3.1.  Category 1: Requirement . . . . . . . . . . . . . . . . .   5
     3.2.  Category 2: Resource  . . . . . . . . . . . . . . . . . .   6
   4.  Data Field of Bounded Latency Information . . . . . . . . . .   6
   5.  Encapsulation of Bounded Latency Information  . . . . . . . .   9
     5.1.  DetNet Data Plane of IP . . . . . . . . . . . . . . . . .   9
     5.2.  DetNet Data Plane of MPLS . . . . . . . . . . . . . . . .  11
     5.3.  DetNet Data Plane of MPLS over UDP/IP . . . . . . . . . .  12
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
     6.1.  New Destination Options and Hop-by-Hop Options  . . . . .  13
     6.2.  New Type of MPLS Extension Header . . . . . . . . . . . .  14
     6.3.  New Subregistry of Bounded Latency Information Type . . .  14
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  17
   Appendix A.  BLI Examples . . . . . . . . . . . . . . . . . . . .  17
     A.1.  Cycle Based Algorithms  . . . . . . . . . . . . . . . . .  18
     A.2.  Time Slot Based Algorithms  . . . . . . . . . . . . . . .  18
     A.3.  Budget Based Algorithms . . . . . . . . . . . . . . . . .  18
     A.4.  Deadline Based Algorithms . . . . . . . . . . . . . . . .  19
     A.5.  Priority Based Algorithms . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20

1.  Introduction

   DetNet [RFC8655] provides the capability to carry specified unicast
   or multicast data flows with extremely low data loss rates and
   bounded end-to-end latency within a network domain.  Three primary
   goals of DetNet QoS are defined in section 3.1 of [RFC8655]:






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   *  Minimum and maximum end-to-end latency from source to destination,
      timely delivery, and bounded jitter (packet delay variation)
      derived from these constraints.

   *  Packet loss ratio under various assumptions as to the operational
      states of the nodes and links.

   *  An upper bound on out-of-order packet delivery.  It is worth
      noting that some DetNet applications are unable to tolerate any
      out-of-order delivery.

   To fulfill the goals of DetNet QoS, DetNet architecture [RFC8655]
   defines a DetNet data plane protocol stack, which includes DetNet
   forwarding and service sub-layers.  Specifically, DetNet data plane
   framework [RFC8938] specifies two metadata of flow identity and
   sequence number to be encoded in data plane.  Flow-ID is used for
   identification of the flow or aggregate flow to decide the DetNet
   traffic treatment and PREOF in both sub-layers.  At the same time,
   sequence number is only used for PREOF in service sub-layer.

   For IP DetNet data plane, [RFC8939] specifies a method of using
   6-tuple to identify DetNet flows.  Management and control information
   defined in DetNet YANG module [I-D.ietf-detnet-yang] is used to
   select the forwarding outgoing interface and next hop.  It is stated
   that the allocation of system resources and provisioning of related
   parameters is used for DetNet traffic treatment.  However, [RFC8939]
   doesn't further specify the related parameters used in data plane.

   In [RFC8964], DetNet Control Word (d-CW), DetNet service label
   (S-Label), and DetNet MPLS forwarding label(s) (F-Label) are defined
   for the MPLS-based DetNet data plane encapsulation, where the first
   two information is mainly used for the DetNet service sub-layer
   functions, the last information is used for the DetNet forwarding
   sub-layer functions.  DetNet controller plane takes the
   responsibility to provision both flow identification information and
   the flow-specific resources needed to provide traffic treatment to
   meet each flow's service requirements.  There is no specification in
   MPLS DetNet data plane to empower the packet treatment capabilities.

   There are also other specifications of DetNet data planes such as
   [RFC9023], [RFC9024], [RFC9025], [RFC9037], and [RFC9056].  These
   documents specifies the DetNet data planes and interworking
   technologies of one type of network operating over another sub-
   network in order to extend the DetNet service range.  However, these
   documents do not introduce new procedure or process, but to follow
   the specifications defined in [RFC8939] and [RFC8964].





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   To meet the requirements for large-scale deterministic networks and
   support the bounded latency objective specified in
   [I-D.liu-detnet-large-scale-requirements], DetNet data plane is
   required to be enhanced in the following aspects:

   *  Explicit inclusion of the metadata used for traffic treatment,
      especially for bounded latency and jitter, when considering the
      support of DetNet flows scalability in large scale DetNet networks

   *  Compatibility to different options of queuing, shaping, policing
      or any other underlying network technologies, in order to provide
      bounded latency

   *  Minimize the end-to-end delay difference of multiple forwarding
      paths that are used for packet replication and elimination

   *  DetNet data plane processing of DetNet flow coexists with the non-
      DetNet flows

   This documents provides a method to extend DetNet data plane by
   introducing Bounded Latency Information (BLI), which facilitates
   DetNet transit nodes to guarantee the bounded latency transmission in
   data plane.  The resources include the QoS mechanisms, scheduling
   mechanisms, or any other mechanisms from underlying network layer so
   as to support bounded latency.  This document also proposes a format
   of bounded latency information and its encapsulations on DetNet data
   planes.



2.  Terminology and Conventions

2.1.  Requirement Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.


2.2.  Terminology

   The abbreviations used in this document are:

   BLI: Bounded Latency Information

   PREOF: Packet Replication, Elimination, and Ordering Functions



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3.  Design of DetNet Enhanced Data Plane

   In order to support the enhanced traffic treatment functions, such as
   bounded latency, DetNet data plane is enhanced by carrying a new
   defined metadata information in DetNet service packets: Bounded
   Latency Information (BLI).

   DetNet uses either one or combination of QoS related and resource
   allocation technologies to ensure the end-to-end bounded latency.
   [I-D.ietf-detnet-bounded-latency] introduces a set of scheduling
   mechanisms can be used to assure the bounded latency.
   [I-D.stein-srtsn] uses a single stack data structure to provide a
   unified approach to forwarding and deadline based scheduling.  Noted
   that in most scheduling process, an ancillary information is required
   to be transmitted between DetNet nodes to facilitate local
   scheduling.  In this document, this ancillary information is named
   bounded latency information.  Bounded latency information is
   transmitted across multiple DetNet transit nodes and used by the
   DetNet forwarding sub-layer.

   To cope with a variety of scheduling mechanisms and transfer
   different information in a uniform format in data plane, the bounded
   latency information is abstracted and classified into two categories:
   requirement and resource.

3.1.  Category 1: Requirement

   Bounded latency information in the requirement category may include
   the information like the end-to-end delay budget, local delay budget,
   local deadline, delay variation budget, local delay variation budget
   etc.  For example, end-to-end delay budget describes the upper
   bounded latency value of DetNet flow in network.  Then DetNet node
   may use this information to determine the packet priority or which
   queue can be used to transmit this packet.  Local delay budget is a
   variation of end-to-end delay budget when multiple DetNet nodes may
   have same or different delay budget time of each in DetNet network.
   Deadline is straightforward to indicate how much time is left for
   this packet to meet the upper bounded latency requirement.  Similar
   practice in 6LoWPANs is given by [RFC9034].  The usage of this
   information is similar to the delay budget information when DetNet
   node decides the priority or queue for the packet forwarding.  Delay
   variation [I-D.mohammadpour-detnet-bounded-delay-variation] is
   another deterministic goal required by DetNet and should be
   considered in scheduling process when it is required.  Priority can
   also be a type of requirement.  DetNet application may assign its
   priority by different meanings and formats, which may not be
   equivalently fulfilled by existing QoS priority.




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3.2.  Category 2: Resource

   Bounded latency information in the resource category includes the
   information like cycle ID, queue ID, and time slot ID etc.  Since
   cycles, queues, or time slots are the real resources can be allocated
   for DetNet flow, they are named as the time resource ID.  For
   example, time resource ID can represent a cycle ID when cyclic
   queuing mechanism is used on DetNet node.  Time resource ID can also
   represent a queue ID when queue based scheduling mechanism is locally
   used on DetNet node.  Time resource ID can represent a time slot ID
   too, when a time slot based mechanism like [RFC9030] is used.

4.  Data Field of Bounded Latency Information

   This section introduces the data field of bounded latency information
   in DetNet data plane.  The format of the data field is shown as
   follows.


   +---------------+-------------+-------------+-------------+
   |   BLI Type    |   Format    |     Flag    |   Reserved  |
   +---------------+-------------+---------------------------+
   |                                                         ~
   ~         Bounded Latency Information (variable size)     ~
   ~                                                         |
   +---------------------------------------------------------+

   Figure 1: Data Field of Bounded Latency Information

   where:

   *  Bounded Latency Information Type: 8-bit identifier to represent
      the type of bounded latency information.  A new registry is
      expected to be created and the value is assigned by IANA.  Table 1
      lists the value of BLI Type and the corresponding Bounded Latency
      Information defined so far,















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   +----------------+---------------------------------------+
   | BLI Type Value |      Bounded Latency Information      |
   +----------------+---------------------------------------+
   |        0       |               Reserved                |
   +----------------+---------------------------------------+
   |        1       |           Time resource ID            |
   +----------------+---------------------------------------+
   |        2       |               Priority                |
   +----------------+---------------------------------------+
   |        3       |        End-to-end delay budget        |
   +----------------+---------------------------------------+
   |        4       |           Local delay budget          |
   +----------------+---------------------------------------+
   |        5       |           End-to-end deadline         |
   +----------------+---------------------------------------+
   |        6       |           Local deadline              |
   +----------------+---------------------------------------+
   |        7       |   End-to-end delay variation budget   |
   +----------------+---------------------------------------+
   |        8       |      Local delay variation budget     |
   +----------------+---------------------------------------+

   Table 1: Bounded Latency Information Type and Value

   *  Format: 8-bit value to indicate the format of bounded latency
      information.  For example, the format could be 16-bit unsigned
      integer, 32-bit unsigned integer, PTP or NTP timestamp, and other
      pre-configured formats.  Table 2 lists the value of Format and the
      corresponding Format defined so far,


      +--------------+-------------------------+
      | Format Value |          Format         |
      +--------------+-------------------------+
      |      1       | 32-bit unsigned Integer |
      +--------------+-------------------------+
      |      2       | 16-bit unsigned Integer |
      +--------------+-------------------------+
      |      3       |  8-bit unsigned Integer |
      +--------------+-------------------------+
      |      4       |   PTP 80-bit Timestamp  |
      +--------------+-------------------------+
      |      5       |   PTP 64-bit Timestamp  |
      +--------------+-------------------------+
      |      6       |   NTP 64-bit Timestamp  |
      +--------------+-------------------------+
      |      7       |   NTP 32-bit Timestamp  |
      +--------------+-------------------------+



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   Table 2: Format

   Bounded Latency Information Type and Format are used together to
   specify the type, length and format of the bounded latency
   information.

      Reserved: Reserved for future usage.

      Time resource ID: the identifier to indicate the underlying
      resources used for bounded latency.  The format is 32-bit unsigned
      integer.

      Priority: QoS priority of the DetNet service packet.  As six bits
      of the Differentiated Services Field [RFC2474] are used as a
      codepoint (DSCP), the format of priority is 8-bit unsigned
      integer.

      End-to-end delay budget: the end-to-end delay requirement of
      DetNet service packet.  The format is 32-bit unsigned Integer.

      Local delay budget: the per hop delay requirement of DetNet
      service packet on this network node.  The format is 32-bit
      unsigned Integer.

      End-to-end deadline: the time when the packet must arrive at the
      final destination or exit the DetNet network.  This time is
      usually the birth time plus the end-to-end delay budget.  The
      format is the timestamp with proper length.

      Local deadline: the time when the packet must exit this network
      node.  The format is the timestamp with proper length.

      End-to-end delay variation budget: the end-to-end delay variation
      requirement of DetNet service packet.  The format is 16-bit
      unsigned Integer.

      Local delay variation budget: the per hop delay variation
      requirement of DetNet service packet on this network node.  The
      format is 16-bit unsigned Integer.


   *  Flags: 8 bits of flags.  A new registry "Bounded Latency Flags" is
      expected to be created.  At the writing time, all flags are unused
      and undefined.







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    0 1 2 3 4 5 6 7
   +-+-+-+-+-+-+-+-+
   |U U U U U U U U|
   +-+-+-+-+-+-+-+-+

   Figure 2: Flag

   *  Reserved: Keeps zero when it is not specified.

   *  Bounded Latency Information: indicates the bounded latency
      information used for local scheduling processing.  Table 1 shows
      the bounded latency information type and the corresponding values.
      The bounded latency information is different depending on the type
      of bounded latency information.

5.  Encapsulation of Bounded Latency Information

   BLI data field can be encapsulated in different DetNet data planes.


5.1.  DetNet Data Plane of IP

   For IPv6 based DetNet data plane, the data field of bounded latency
   information is recommended to be carried in IPv6 Extension Header
   Options, called Bounded Latency Information Option, shown in the
   following Figure.


   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 2
                                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                   | Option Type   | Opt Data Len  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   BLI Type    |     Format    |    Flag       |    Reserved   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               ~
   ~         Bounded Latency Information (variable size)           ~
   ~                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Figure 3: Bounded Latency Information Option

   *  Option Type: 8-bit identifier of the type of option.  Value TBD by
      IANA; the highest-order 3 bits of this field is 001 to skip over
      this option and continue processing the header if the processing
      IPv6 node does not recognize the Option Type and to permit the
      Option Data may change en route to the destination of packet.




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   *  Opt Data Len: 8-bit unsigned integer.  Length of the Option Data
      field of this option, in octets.

   *  For Bounded Latency Information data field, see section 4 for
      details.

   Bounded latency information data field is encapsulated in either IPv6
   Hop-by-Hop Options header or IPv6 Destination Options header
   depending on the processing happens at each hop or at the last hop.
   More than one bounded latency information can appear in one Bounded
   Latency Information Option.  The Option Data Length and the Format
   are used to locate every bounded latency information.  The
   encapsulation of Bounded Latency Information Option is shown in
   Figure 4 and Figure 5.


   +--------------------------------------+
   |          DetNet App-Flow             |
   |        (Original IP) Packet          |
   +--------------------------------------+
   |        UDP/GRE/IPSec... Header       |
   +--------------------------------------+
   |            Other IPv6 EHs            |
   +--------------------------------------+
   |     IPv6 Hop-by-Hop Options Header   |
   | (Bounded Latency Information Option) |
   +--------------------------------------+
   |             IPv6 Header              |
   +--------------------------------------+
   |              Data-Link               |
   +--------------------------------------+
   |              Physical                |
   +--------------------------------------+

   Figure 4: Encapsulation of BLI Option in IPv6 Hop-by-Hop Options
   Headers















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   +--------------------------------------+
   |          DetNet App-Flow             |
   |        (Original IP) Packet          |
   +--------------------------------------+
   |        UDP/GRE/IPSec... Header       |
   +--------------------------------------+
   |     IPv6 Destination Options Header  |
   | (Bounded Latency Information Option) |
   +--------------------------------------+
   |            Other IPv6 EHs            |
   +--------------------------------------+
   |             IPv6 Header              |
   +--------------------------------------+
   |              Data-Link               |
   +--------------------------------------+
   |              Physical                |
   +--------------------------------------+

   Figure 5: Encapsulation of BLI Option in IPv6 Destination Options
   Headers


5.2.  DetNet Data Plane of MPLS

   An MPLS extension header is proposed in
   [I-D.song-mpls-extension-header].  An MPLS Extension Header (EH)
   encapsulated with the format of bounded latency information is called
   Bounded Latency Information Extension Header (BLIEH) and shown in
   Figure 6.


   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 2
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     NH        |     HLEN      |      EXT      |    Reserved   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   BLI Type    |     Format    |     Flag      |    Reserved   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               ~
   ~         Bounded Latency Information (variable size)           ~
   ~                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Figure 6: Bounded Latency Information Extension Header

   *  NH: 8-bit indicator for the Next Header.  This field identifies
      the type of the EH immediately following this EH.




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   *  HLEN: 8-bit unsigned integer for the Extension Header Length in
      4-octet units, not including the first 4 octets.

   *  EXT: 8-bit optional type extension.

   The encapsulation of bounded latency information in MPLS extension
   headers with MPLS label stack is shown in the following figure.  More
   than one BLI can be carried in one Bounded Latency Information
   Extension Header (BLIEH).


   0                                  31
   +--------+--------+--------+--------+  \
   |                                   |  |
   ~     MPLS Label Stack              ~  |
   |                                   |  |
   +--------+--------+--------+--------+  |
   |     EH Indicator (TBD)            |   > MPLS Label Stack
   +--------+--------+--------+--------+  |  (extended with EHI)
   |                                   |  |
   ~     MPLS Label Stack              ~  |
   |                                   |  |
   +--------+--------+--------+--------+ <
   | Header of Extension Headers (HEH) |  |
   +--------+--------+--------+--------+  |
   |                                   | > MPLS EH Fields
   ~ Extension Header (EH)  with BLI  ~   |  (new)
   |                                   |  |
   +--------+--------+--------+--------+ <
   |                                   |  |
   ~    Upper Layer Headers/Payload    ~   > MPLS Payload
   |                                   |  |  (as is)
   +--------+--------+--------+--------+  /

   Figure 7: MPLS Encapsulation of Bounded Latency Information Extension
   Header

5.3.  DetNet Data Plane of MPLS over UDP/IP

   This document describes a DetNet IP encapsulation that includes the
   bounded latency information based on the DetNet MPLS over UDP/IP data
   plane [RFC9025], i.e., leveraging the MPLS-over-UDP technology.  The
   bounded latency guarantee capable DetNet IP encapsulation builds on
   encapsulating DetNet PW over an IP/UDP tunnel [RFC7510].  It is noted
   that the format of MPLS Bounded Latency Extension Header (BLIEH)
   after UDP header is the same with the format of MPLS Bounded Latency
   Extension Header (BLIEH) defined in section 5.2, as well as without
   using any MPLS forwarding labels.  The encapsulation of bounded



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   latency information in DetNet Data Plane of MPLS over UDP/IP is shown
   in the following figure.


   0                                 31
   +----------------------------------+
   |                                  |
   |         DetNet App-Flow          |
   |       (original IP) Packet       |
   |                                  |
   +----------------------------------+<--\
   |                                  |    |
   ~ MPLS Bounded Latency Information ~    |
   ~     Extension Header (BLIEH)     ~    |
   |                                  |    |
   +----------------------------------+    +--> Bounded latency support
   |      UDP/GRE/IPSec... Header     |    |    DetNet IP data
   +----------------------------------+    |    plane encapsulation
   |            IP Header             |    |
   +----------------------------------+<--/
   |            Data-Link             |
   +----------------------------------+
   |             Physical             |
   +----------------------------------+

   Figure 8: IPv6 extension option of bounded latency

6.  IANA Considerations


6.1.  New Destination Options and Hop-by-Hop Options

   IANA is requested to allocate a value of "Destination Options and
   Hop-by-Hop Options" under "Internet Protocol Version 6 (IPv6)
   Parameters" registry.  The suggested value is:


   +------+-----+-----+-------+---------------------+-----------+
   | Hex  | act | chg | rest  |     Description     | Reference |
   +------+-----+-----+-------+---------------------+-----------+
   |  TBD | 00  |  1  |  TBD  |       BLI Option    | This I-D  |
   +------+-----+-----+-------+---------------------+-----------+

   Bounded Latency Information Option







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6.2.  New Type of MPLS Extension Header

   IANA is requested to allocate a 8-bit indicator for the Next Header
   to the Bounded Latency Extension Header.

6.3.  New Subregistry of Bounded Latency Information Type

   IANA is requested to define a new subregistry of "Bounded Latency
   Information Type" for the "Bounded Latency Information Option" under
   "Internet Protocol Version 6 (IPv6) Parameters" registry.

   This new subregistry will include the following registries:


   +-----------------+---------------------------------+-----------+
   | Suggested Value |            Meaning              | Reference |
   +-----------------+---------------------------------+-----------+
   |       TBD       |            Reserved             | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |        Time resource ID         | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |            Priority             | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |    End-to-end delay budget      | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |        Local delay budget       | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |        End-to-end deadline      | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |        Local deadline           | This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |End-to-end delay variation budget| This I-D  |
   +-----------------+---------------------------------+-----------+
   |       TBD       |   Local delay variation budget  | This I-D  |
   +-----------------+---------------------------------+-----------+

   Bounded Latency Information Type

7.  Security Considerations

   TBD

8.  References

8.1.  Normative References






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   [I-D.ietf-detnet-bounded-latency]
              Finn, N., Le Boudec, J., Mohammadpour, E., Zhang, J., and
              B. Varga, "Deterministic Networking (DetNet) Bounded
              Latency", Work in Progress, Internet-Draft, draft-ietf-
              detnet-bounded-latency-10, 8 April 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-detnet-
              bounded-latency-10>.

   [I-D.ietf-detnet-yang]
              Geng, X., Ryoo, Y., Fedyk, D., Rahman, R., and Z. Li,
              "Deterministic Networking (DetNet) YANG Model", Work in
              Progress, Internet-Draft, draft-ietf-detnet-yang-18, 10
              July 2023, <https://datatracker.ietf.org/doc/html/draft-
              ietf-detnet-yang-18>.

   [I-D.liu-detnet-large-scale-requirements]
              Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
              zhushiyin, and X. Geng, "Requirements for Large-Scale
              Deterministic Networks", Work in Progress, Internet-Draft,
              draft-liu-detnet-large-scale-requirements-05, 20 October
              2022, <https://datatracker.ietf.org/doc/html/draft-liu-
              detnet-large-scale-requirements-05>.

   [I-D.mohammadpour-detnet-bounded-delay-variation]
              Mohammadpour, E. and J. Le Boudec, "DetNet Bounded Packet-
              Delay-Variation", Work in Progress, Internet-Draft, draft-
              mohammadpour-detnet-bounded-delay-variation-00, 10
              September 2021, <https://datatracker.ietf.org/doc/html/
              draft-mohammadpour-detnet-bounded-delay-variation-00>.

   [I-D.song-mpls-extension-header]
              Song, H., Zhou, T., Andersson, L., Zhang, Z. J., and R.
              Gandhi, "MPLS Network Actions using Post-Stack Extension
              Headers", Work in Progress, Internet-Draft, draft-song-
              mpls-extension-header-13, 11 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-song-mpls-
              extension-header-13>.

   [I-D.stein-srtsn]
              Stein, Y. J., "Segment Routed Time Sensitive Networking",
              Work in Progress, Internet-Draft, draft-stein-srtsn-01, 29
              August 2021, <https://datatracker.ietf.org/doc/html/draft-
              stein-srtsn-01>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.



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   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              DOI 10.17487/RFC2474, December 1998,
              <https://www.rfc-editor.org/info/rfc2474>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8655]  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>.

   [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>.

   [RFC8939]  Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
              Bryant, "Deterministic Networking (DetNet) Data Plane:
              IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
              <https://www.rfc-editor.org/info/rfc8939>.

   [RFC8964]  Varga, B., Ed., Farkas, J., Berger, L., Malis, A., Bryant,
              S., and J. Korhonen, "Deterministic Networking (DetNet)
              Data Plane: MPLS", RFC 8964, DOI 10.17487/RFC8964, January
              2021, <https://www.rfc-editor.org/info/rfc8964>.

   [RFC9023]  Varga, B., Ed., Farkas, J., Malis, A., and S. Bryant,
              "Deterministic Networking (DetNet) Data Plane: IP over
              IEEE 802.1 Time-Sensitive Networking (TSN)", RFC 9023,
              DOI 10.17487/RFC9023, June 2021,
              <https://www.rfc-editor.org/info/rfc9023>.

   [RFC9024]  Varga, B., Ed., Farkas, J., Malis, A., Bryant, S., and D.
              Fedyk, "Deterministic Networking (DetNet) Data Plane: IEEE
              802.1 Time-Sensitive Networking over MPLS", RFC 9024,
              DOI 10.17487/RFC9024, June 2021,
              <https://www.rfc-editor.org/info/rfc9024>.

   [RFC9025]  Varga, B., Ed., Farkas, J., Berger, L., Malis, A., and S.
              Bryant, "Deterministic Networking (DetNet) Data Plane:
              MPLS over UDP/IP", RFC 9025, DOI 10.17487/RFC9025, April
              2021, <https://www.rfc-editor.org/info/rfc9025>.





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   [RFC9030]  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>.

   [RFC9034]  Thomas, L., Anamalamudi, S., Anand, S.V.R., Hegde, M., and
              C. Perkins, "Packet Delivery Deadline Time in the Routing
              Header for IPv6 over Low-Power Wireless Personal Area
              Networks (6LoWPANs)", RFC 9034, DOI 10.17487/RFC9034, June
              2021, <https://www.rfc-editor.org/info/rfc9034>.

   [RFC9037]  Varga, B., Ed., Farkas, J., Malis, A., and S. Bryant,
              "Deterministic Networking (DetNet) Data Plane: MPLS over
              IEEE 802.1 Time-Sensitive Networking (TSN)", RFC 9037,
              DOI 10.17487/RFC9037, June 2021,
              <https://www.rfc-editor.org/info/rfc9037>.

   [RFC9056]  Varga, B., Ed., Berger, L., Fedyk, D., Bryant, S., and J.
              Korhonen, "Deterministic Networking (DetNet) Data Plane:
              IP over MPLS", RFC 9056, DOI 10.17487/RFC9056, October
              2021, <https://www.rfc-editor.org/info/rfc9056>.

8.2.  Informative References

   [I-D.peng-detnet-deadline-based-forwarding]
              Peng, S., Du, Z., Basu, K., cheng, Yang, D., and C. Liu,
              "Deadline Based Deterministic Forwarding", Work in
              Progress, Internet-Draft, draft-peng-detnet-deadline-
              based-forwarding-07, 18 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-peng-detnet-
              deadline-based-forwarding-07>.

   [I-D.yizhou-detnet-ipv6-options-for-cqf-variant]
              Li, Y., Ren, S., Li, G., Yang, F., Ryoo, J., and P. Liu,
              "IPv6 Options for Cyclic Queuing and Forwarding Variants",
              Work in Progress, Internet-Draft, draft-yizhou-detnet-
              ipv6-options-for-cqf-variant-02, 26 April 2023,
              <https://datatracker.ietf.org/doc/html/draft-yizhou-
              detnet-ipv6-options-for-cqf-variant-02>.

Appendix A.  BLI Examples

   The following examples are provided to give instructions on how
   Bounded Latency Information is used when network node implements
   different algorithms to guarantee the bounded latency transmission.






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A.1.  Cycle Based Algorithms

   When network node implements cycle based algorithms for example
   [I-D.yizhou-detnet-ipv6-options-for-cqf-variant] , cycles are the
   local resources used to guarantee the bounded latency transmission.
   Cycle ID is expected to be carried in data plane.  Thus, the data
   field of BLI is suggested as follows:


   +---------------+--------------+--------------+--------------+
   | BLI Type (=1) |   Format(=1) |      Flag    |    Reserved  |
   +---------------+--------------+--------------+--------------+
   |                        Cycle ID                            |
   +------------------------------------------------------------+

   Figure A.1: Data Field of BLI Used With Cycle Based Algorithms

A.2.  Time Slot Based Algorithms

   When network node implements time slot based algorithms, time slots
   are the local resources used to guarantee the bounded latency
   transmission.  Time Slot ID is expected to be carried in data plane.
   Thus, the data field of BLI is suggested as follows:


   +---------------+--------------+--------------+--------------+
   | BLI Type (=1) |   Format(=1) |      Flag    |    Reserved  |
   +---------------+--------------+--------------+--------------+
   |                         Time Slot ID                       |
   +------------------------------------------------------------+

   Figure A.2: Data Field of BLI Used With Time Slot Based Algorithms

A.3.  Budget Based Algorithms

   When network node implements the budget based algorithms to provide
   bounded latency transmission, end to end or per hop delay budget or
   delay variation budget information is the requirement proposed from
   the services and expected to be carried in data plane.  The data
   fields of BLI used with delay budget based algorithms are suggested
   as follows:


   +---------------+---------------+---------------+--------------+
   | BLI Type(=3/4)|   Format(=1)  |      Flag     |    Reserved  |
   +---------------+---------------+---------------+--------------+
   |                    E2E/Local Delay Budget                    |
   +--------------------------------------------------------------+



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   Figure A.3: Data Field of BLI Used With Delay Budget Based Algorithms

   The data fields of BLI used with delay variation budget based
   algorithms are suggested as follows:


   +---------------+----------------+---------------+---------------+
   | BLI Type(=7/8)|    Format(=2)  |      Flag     |    Reserved   |
   +---------------+----------------+---------------+---------------+
   |E2E/Local Delay Variation Budget|
   +--------------------------------+

   Figure A.4: Data Field of BLI Used With Delay Variation Budget Based
   Algorithms

A.4.  Deadline Based Algorithms

   When network node implements deadline based algorithms like EDF,
   Deadine forwarding [I-D.peng-detnet-deadline-based-forwarding] to
   provide bounded latency transmission, end to end or per hop packet
   deadline is the requirement proposed from the services and expected
   to be carried in data plane.  The data fields of BLI used with
   deadline based algorithms are suggested as follows:


   +---------------+---------------+---------------+--------------+
   | BLI Type(=5/6)|   Format(=5)  |      Flag     |    Reserved  |
   +---------------+---------------+---------------+--------------+
   |                      E2E/Local Deadline                      |
   |                                                              |
   +--------------------------------------------------------------+

   Figure A.5: Data Field of BLI Used With Deadline Based Algorithms

A.5.  Priority Based Algorithms

   When network node implements priority based algorithms, priority is
   the requirement proposed from the services.  Priority ID is expected
   to be carried in data plane.  The data field of BLI is suggested as
   follows:











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   +---------------+--------------+--------------+--------------+
   | BLI Type (=2) |   Format(=3) |      Flag    |    Reserved  |
   +---------------+--------------+--------------+--------------+
   |   Priority ID |
   +---------------+

   Figure A.6: Data Field of BLI Used With Priority Based Algorithms

Authors' Addresses

   Xuesong Geng
   Huawei
   156 Beiqing Rd.
   Beijing
   100095
   China
   Email: gengxuesong@huawei.com


   Tianran Zhou
   Huawei
   156 Beiqing Rd.
   Beijing
   100095
   China
   Email: zhoutianran@huawei.com


   Li Zhang
   Huawei
   156 Beiqing Rd.
   Beijing
   100095
   China
   Email: zhangli344@huawei.com


   Zongpeng Du
   China Mobile
   No.32 XuanWuMen West Street
   Beijing
   100053
   China
   Email: duzongpeng@foxmail.com







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