LSR                                                         Shaofu. Peng
Internet-Draft                                                       ZTE
Intended status: Standards Track                        24 December 2024
Expires: 27 June 2025


          IGP Extensions for Deterministic Traffic Engineering
          draft-peng-lsr-deterministic-traffic-engineering-03

Abstract

   This document describes IGP extensions to support Traffic Engineering
   (TE) of deterministic routing, by specifying new information that a
   router can place in the advertisement of neighbors.  This information
   describes additional details regarding the state of the network that
   are useful for deterministic traffic engineering path computations.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 27 June 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   provided without warranty as described in the Revised BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Deterministic Forwarding Resources  . . . . . . . . . . . . .   4
   4.  ISIS Advertisement of Link Scheduling Capability  . . . . . .   6
   5.  ISIS Advertisement of DetNet Maximum Reservable Bandwidth . .   8
   6.  ISIS Advertisement of DetNet Unreserved Bandwidth . . . . . .  10
   7.  ISIS Advertisement of DetNet Maximum Reservable Burst . . . .  11
   8.  ISIS Advertisement of DetNet Unreserved Burst . . . . . . . .  13
   9.  OSPF Advertisement of Link Deterministic Resource . . . . . .  14
   10. Announcement Suppression  . . . . . . . . . . . . . . . . . .  14
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  14
   13. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  15
   14. References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     14.1.  Normative References . . . . . . . . . . . . . . . . . .  15
     14.2.  Informative References . . . . . . . . . . . . . . . . .  16
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction

   [RFC8655] describes the architecture of a deterministic networking
   (DetNet) and defines the QoS goals of deterministic forwarding: 1)
   Minimum and maximum end-to-end latency from source to destination,
   timely delivery, and bounded jitter (packet delay variation); 2) A
   bounded packet loss ratio under various assumptions about the
   operational states of the nodes and links; 3) An upper bound on out-
   of-order packet delivery.  In order to achieve these goals, DetNet
   use resource reservation, explicit routing, and service protection,
   as well as other means.  A deterministic forwarding path is typically
   (but not necessarily) an explicit route so that it does not suffer
   temporary interruptions caused by the convergence of routing or
   bridging protocols.

   The IEEE 802.1 WG has specified a set of queuing, shaping, and
   scheduling algorithms that are mainly used for L2 networks, such as
   ATS [IEEE802.1Qcr], CBS [IEEE802.1Qav], and CQF/ECQF [IEEE802.1Qch]
   [IEEE802.1Qdv].  There are some challenges in applying these
   mechanisms to IP/MPLS network, mainly due to the cost of per flow
   state, or limited service scale.  There are also some enhanced data
   plane (EDP) queueing mechanisms under discussion in DetNet working
   group to meet large scaling requirements, such as C-SCORE
   [I-D.joung-detnet-stateless-fair-queuing], EDF
   [I-D.peng-detnet-deadline-based-forwarding], TQF
   [I-D.peng-detnet-packet-timeslot-mechanism], gLBF
   [I-D.eckert-detnet-glbf].  According to [Net-Calculus], queueing
   mechanisms may be roughly classified into two categories: rate based,



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   and delay based.  For example, ATS, CBS, C-SCORE, and gLBF are rate
   based mechanisms, while CQF/ECQF, EDF, and TQF are delay based
   mechanisms.  It can also be classified from other dimensions, such as
   work-conserving or non work-conserving.  One mechanism may correspond
   to multiple categories simultaneously.

   The latency bound provided by rate based mechanisms is generally
   inversely proportional to the service rate of the flow or flow
   aggregate, and overestimated.  While the latency bound provided by
   delay based mechanisms is related to the time resources consumed by
   the flow by accurately planning the scheduling orders (e.g., slot,
   deadline), and is an accurate preset value.

   In order to provide DetNet QoS, queueing mechanisms not only specify
   scheduling techniques on the data plane, but also quantify forwarding
   resources to provide a foundation for admission control of service
   flows.  Generally, the successful operation of a DetNet queueing
   mechanism relies on admission control of the data volume and data
   rate allowed to be released into the network, and avoiding burst
   accumulation at intermediate nodes.  The deterministic forwarding
   resources will be designed around two factors: data volume and data
   rate.  Note that in L4S architecture [RFC9330], the endpoint of
   transport layer also dynamically control these two factors in
   response to network congestion indications to get low latency target,
   however, it rely on heuristics that can either undershoot or
   overshoot the bottleneck bandwidth, and latency bound cannot be
   guaranteed.

   This document describes IGP extensions to advertise forwarding
   resources related with deterministic queueing mechanisms in the
   network, which may be used for the deterministic traffic engineering
   path computation.

2.  Requirements 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.











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3.  Deterministic Forwarding Resources

   One or more queueing mechanisms may be enabled on the same link, each
   of which may support single or multiple instances (or considered as
   multiple capability levels), and each instance has dedicated
   deterministic forwarding resources.  For example, the traditional
   Strict Priority (SP) mechanism may support 8 traffic classes and each
   has the Maximum Reservable Bandwidth resource.  It is known that SP
   faces challenges in providing DetNet QoS.  For any queueing mechanism
   that can guarantee DetNet QoS, it is similar to support multiple
   instances, especially the deterministic forwarding resources involved
   can be summarized into two types:

   *  Bandwidth: refers to the share of link capacity allocated by an
      instance.  In some contexts, bandwidth is also replaced by terms
      such as service rate or data rate.

   *  Burst: refers to the data volume that an instance is allowed to
      send during a busy period of scheduling.

   For ATS, CBS, or gLBF, they may support multiple instances (such as 8
   traffic classes ), and each instance has dedicated Maximum Reservable
   Bandwidth (MRBan) and Maximum Reservable Burst (MRBur).  DetNet flows
   mapped to a certain instance will consume the resources of that
   instance.  The MRBan and MRBur corresponding to a certain instance
   are the dominator factors for the worst-case per-hop latency for that
   instance.

   For C-SCORE, it may be considered to support a single instance, and
   have Maximum Reservable Bandwidth (MRBan) and Maximum Reservable
   Burst (MRBur).  DetNet flows mapped to C-SCORE will consume the
   resources of this instance.  The Maximum Reservable Burst resource
   provided by C-SCORE is actually determined by the physical size of
   the used sorted-queue, which stores all concurrent incoming bursts.
   However, the MRBan and MRBur of C-SCORE are only used for admitting
   condition check, and the worst-case per-hop latency for each flow is
   only determined by flow's service rate and burst size.

   For CQF/ECQF, they may support multiple instances each with specific
   cycle duration (e.g., 10us).  Each instance has dedicated Maximum
   Reservable Bandwidth (MRBan) and Maximum Reservable Burst (MRBur),
   where MRBur = MRBan * cycle duration.  Note that MRBur represents the
   resources of the entire instance, not the resources of a specific
   cycle under the instance (e.g., a instance may have cycle a, b, c).
   DetNet flows mapped to a certain instance will consume the resources
   of that instance.  However, the MRBan and MRBur of CQF/ECQF are only
   used for admitting condition check, and the worst-case per-hop delay
   is determined by the cycle duration.



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   For EDF, it may support multiple instances each with specific delay
   level (e.g., 10us).  Each instance has dedicated Maximum Reservable
   Bandwidth (MRBan) and Maximum Reservable Burst (MRBur).  The MRBan
   and MRBur of all instances meet the shcedulability condition.  DetNet
   flows mapped to a certain instance will consume the resources of that
   instance.  However, the MRBan and MRBur of EDF are only used for
   admitting condition check, and the worst-case per-hop delay is
   determined by the delay level.

   For TQF, it may support multiple instances each with specific
   orchestration period (e.g., 1ms) that containing N timeslots.  Each
   instance has dedicated Maximum Reservable Bandwidth (MRBan) and
   Maximum Reservable Burst (MRBur), where MRBur = MRBan * timeslot
   length.  Note that MRBur represents resources for individual
   timeslot, and in general all timeslots have the same MRBur value.
   DetNet flows mapped to a certain instance will consume the resources
   of that instance.  However, the MRBan and MRBur of TQF are only used
   for admitting condition check, and the worst-case per-hop delay is
   determined by the timeslot length, as well as the mapping
   relationship between the incoming and outgoing timeslots.

   The link should also maintain the unused resources of each capability
   level based on the reservation result, i.e., Unused Bandwidth and
   Unused Burst.  Initially, unused resources are equal to the maximum
   available reservable resources, and only the maximum available
   reservable resources need to be advertised by IGP if there is no
   consumption of resources.  The utilized resources are equal to the
   maximum resources minus the unused resources.

   The rate based queueing mechanisms can always use MRBan and MRBur to
   calculate latency bound, as long as the reserved bandwidth and burst
   resources consumed by admitted flows do not exceed MRBan and MRBur,
   respectively.  Alternatively, it may also use the utilized bandwidth
   and bursts to calculate latency bound, which however will change with
   the dynamic admission and release of flows.

   EDF mechanism can always use MRBan and MRBur to check the
   schedulability condition, as long as the reserved bandwidth and burst
   resources consumed by admitted flows do not exceed MRBan and MRBur,
   respectively.  Alternatively, whenever a new flow is admitted, it
   uses the utilized bandwidth and bursts to check the schedulability
   condition.









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4.  ISIS Advertisement of Link Scheduling Capability

   A new IS-IS sub-TLV is defined: the DetNet Scheduling Capability Sub-
   TLV, which is advertised within TLV-22, 222, 23, 223, 141, 25.  For
   each link, multiple DetNet Scheduling Capability Sub-TLVs can be
   included, depending on how many scheduling mechanisms are enabled on
   the link.

   The following format is defined for the DetNet Scheduling Capability
   Sub-TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type        |     Length    |       ST      |     Flags |I|O|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Scheduling Capability Info (variable)           //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                                  Figure 1

   where:

      Type: TBD.

      Length: variable, depending on size of the Scheduling Capability
      Info field.

      ST(Scheduling Type): 1 byte, represents the type of scheduling
      mechanism supported by the link, as below.

         0: Reserved for default or unspecified scheduling mechanisms,
         such as SP (strict priority) that is widely used in the
         network.  It is not recommended to explicitly advertise the
         detailed capability information of default scheduling
         mechanisms by the DetNet Scheduling Capability Sub-TLV.

         1: ATS [IEEE802.1Qcr].

         2: CBS [IEEE802.1Qav].

         3: ATS+CBS [ATSplusCBS].

         4: CQF/ECQF [IEEE802.1Qch] [IEEE802.1Qdv].

         5: EDF [I-D.peng-detnet-deadline-based-forwarding].




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         6: TQF [I-D.peng-detnet-packet-timeslot-mechanism].

         7: C-SCORE [I-D.joung-detnet-stateless-fair-queuing].

         8: gLBF [I-D.eckert-detnet-glbf].

         9~255: To be defined in the future.

      Flags: 1 byte, currently two flags are defined as below:

         I (In-time mode): indicates whether the scheduling mechanism
         supports in-time scheduling mode.  Support if set, otherwise
         not support.  In-time scheduling mode can be understood as
         sending the packet as soon as possible before its bounded
         latency per-hop.

         O (On-time mode): indicates whether the scheduling mechanism
         supports on-time scheduling mode.  Support if set, otherwise
         not support.  On-time scheduling mode can be understood as
         sending the packet as close as possible to its bounded latency
         per-hop.

      Scheduling Capability Info: Includes capability level information
      corresponding to the specific scheduling mechanism type with
      variable size, depending on the ST.

      -  If ST is one of ATS, CBS, ATS+CBS, or gLBF, the field size is 1
         byte, and it contains the number (i.e., n) of traffic classes
         supported by the scheduling mechanism.  Let the first traffic
         class be 0, the last traffic class be n-1, with ascending
         priority order from traffic class 0 to traffic class n.

      -  If ST is CQF/ECQF, the field size is n*2 bytes, and it contains
         n cycle durations, each with 2 bytes, in unit of microseconds.
         For example, the cycle duration may be 10 us, or 20 us, and so
         on.  Different cycle durations represent different CQF
         instances.

      -  If ST is EDF, the field size is 6 bytes, and it contains the
         minimum delay level (2 bytes, in unit of microseconds), maximum
         delay level (2 bytes, in unit of microseconds), and delay level
         interval (2 bytes, in unit of microseconds) supported by the
         EDF scheduling mechanism.  The number of supported delay levels
         can be deduced by n = (maximum delay level - minimum delay
         level) / delay level interval + 1.  For example, the minimum
         delay level may be 10 us, the maximum delay level may be 100
         us, and the delay level interval may be 10 us.




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      -  If ST is TQF, the field size is n*8 bytes, and it contains n
         TQF instances, each with 8 bytes.  These 8 bytes specifically
         include the Orchestration Period Length (4 bytes, in unit of
         microseconds), the amount of timeslots N (2 bytes) within the
         Orchestration Period, and the amount of timeslots M (2 bytes)
         within the Scheduling Period.  The timeslot length can be
         deduced by Orchestration Period Length / N.  For example, the
         Orchestration Period Length may be 1000 us, containing 100
         timeslots, and the Scheduling Period may contain fewer
         timeslots, such as 10.

      -  If ST is C-SCORE, the field size is zero, and there is no need
         to specify capability level information.  It can be considered
         to support a single unified instance.

   For each scheduling mechanism enabled on the link, the DetNet
   Scheduling Capability Sub-TLV SHOULD be advertised once at most.  A
   router receiving multiple DetNet Scheduling Capability Sub-TLVs for
   the same link and same scheduling mechanism, SHOULD select the first
   advertisement in the lowest-numbered LSP.

5.  ISIS Advertisement of DetNet Maximum Reservable Bandwidth

   A new IS-IS sub-TLV is defined: the DetNet Maximum Reservable
   Bandwidth Sub-TLV, which is advertised within TLV-22, 222, 23, 223,
   141, 25.  For each link, multiple DetNet Maximum Reservable Bandwidth
   Sub-TLVs can be included, depending on how many scheduling mechanisms
   are enabled on the link.

   This sub-TLV contains the maximum amount of bandwidth that can be
   reserved in the link with the direction from this node to the
   neighbor, for each instance of a specific scheduling mechanism.  Note
   that oversubscription is prohibited, so this must be less than the
   bandwidth of the link.

   The following format is defined for the DetNet Maximum Reservable
   Bandwidth Sub-TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type        |     Length    |       ST      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Maximum Reservable Bandwidth (variable)         //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                                  Figure 2



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   where:

      Type: TBD.

      Length: variable, depending on size of the Maximum Reservable
      Bandwidth field.

      ST(Scheduling Type): 1 byte, represents the type of scheduling
      mechanism supported by the link, as defined in Section 4.

      Maximum Reservable Bandwidth: includes the maximum reservable
      bandwidth (MRBan) corresponding to the specific scheduling
      mechanism type with variable size, depending on the ST.

      -  If ST is one of ATS, CBS, ATS+CBS, or gLBF, the field size is
         n*4 bytes, and it contains the MRBan per traffic class (4
         bytes, in the unit of bytes per second in IEEE floating point
         format), from traffic class 0 to traffic class n-1.

      -  If ST is CQF/ECQF, the field size is n*6 bytes, and it contains
         n tuple <cycle duration(2B), MRBan(4B)>, where, cycle duration
         in the unit of microseconds, and MRBan in the unit of bytes per
         second in IEEE floating point format.

      -  If ST is EDF, the field size is n*6 bytes, and it contains n
         tuple <delay level(2B), MRBan(4B)>, where, delay level in the
         unit of microseconds, and MRBan in the unit of bytes per second
         in IEEE floating point format.  Note that all delay levels'
         maximum reservable bandwidth must meet the schedulability
         condition.

      -  If ST is TQF, the field size is n*8 bytes, and it contains n
         tuple <OPL(4B), MRBan(4B)>, where, OPL (Orchestration Period
         Length) in the unit of microseconds, and MRBan in the unit of
         bytes per second in IEEE floating point format.

      -  If ST is C-SCORE, the field size is 4 bytes, and it contains
         the MRBan in the unit of bytes per second in IEEE floating
         point format.

   For each scheduling mechanism enabled on the link, the DetNet Maximum
   Reservable Bandwidth Sub-TLV SHOULD be advertised once at most.  A
   router receiving multiple DetNet Maximum Reservable Bandwidth Sub-
   TLVs for the same link and same scheduling mechanism, SHOULD select
   the first advertisement in the lowest-numbered LSP.

   Note that oversubscription is prohibited, so that the sum of MRBan of
   all scheduling mechanisms must be less than the link capacity.



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6.  ISIS Advertisement of DetNet Unreserved Bandwidth

   A new IS-IS sub-TLV is defined: the DetNet Unreserved Bandwidth Sub-
   TLV, which is advertised within TLV-22, 222, 23, 223, 141, 25.  For
   each link, multiple DetNet Unreserved Bandwidth Sub-TLVs can be
   included, depending on how many scheduling mechanisms are enabled on
   the link.

   This sub-TLV contains the amount of bandwidth reservable in the link
   with the direction from this node to the neighbor, for each instance
   of a specific scheduling mechanism.  Initially, the unreserved
   bandwidth equals to the maximum reservable bandwidth.

   The following format is defined for the DetNet Unreserved Bandwidth
   Sub-TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type        |     Length    |       ST      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Unreserved Bandwidth (variable)             //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                                  Figure 3

   where:

      Type: TBD.

      Length: variable, depending on size of the Unreserved Bandwidth
      field.

      ST(Scheduling Type): 1 byte, represents the type of scheduling
      mechanism supported by the link, as defined in Section 4.

      Unreserved Bandwidth: includes the unreserved bandwidth (UBan)
      corresponding to the specific scheduling mechanism type with
      variable size, depending on the ST.

      -  If ST is one of ATS, CBS, ATS+CBS, or gLBF, the field size is
         n*4 bytes, and it contains the UBan per traffic class (4 bytes,
         in the unit of bytes per second in IEEE floating point format),
         from traffic class 0 to traffic class n-1.






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      -  If ST is CQF/ECQF, the field size is n*6 bytes, and it contains
         n tuple <cycle duration(2B), UBan(4B)>, where, cycle duration
         in the unit of microseconds, and UBan in the unit of bytes per
         second in IEEE floating point format.

      -  If ST is EDF, the field size is n*6 bytes, and it contains n
         tuple <delay level(2B), UBan(4B)>, where, delay level in the
         unit of microseconds, and UBan in the unit of bytes per second
         in IEEE floating point format.

      -  If ST is TQF, the field size is n*8 bytes, and it contains n
         tuple <OPL(4B), UBan(4B)>, where, OPL (Orchestration Period
         Length) in the unit of microseconds, and UBan in the unit of
         bytes per second in IEEE floating point format.

      -  If ST is C-SCORE, the field size is 4 bytes, and it contains
         the UBan in the unit of bytes per second in IEEE floating point
         format.

   For each scheduling mechanism enabled on the link, the DetNet
   Unreserved Bandwidth Sub-TLV SHOULD be advertised once at most.  A
   router receiving multiple DetNet Unreserved Bandwidth Sub-TLVs for
   the same link and same scheduling mechanism, SHOULD select the first
   advertisement in the lowest-numbered LSP.

7.  ISIS Advertisement of DetNet Maximum Reservable Burst

   A new IS-IS sub-TLV is defined: the DetNet Maximum Reservable Burst
   Sub-TLV, which is advertised within TLV-22, 222, 23, 223, 141, 25.
   For each link, multiple DetNet Maximum Reservable Burst Sub-TLVs can
   be included, depending on how many scheduling mechanisms are enabled
   on the link.

   The following format is defined for the DetNet Maximum Reservable
   Burst Sub-TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type        |     Length    |       ST      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Maximum Reservable Burst (variable)             //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                                  Figure 4

   where:



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      Type: TBD.

      Length: variable, depending on size of the Maximum Reservable
      Burst field.

      ST(Scheduling Type): 1 byte, represents the type of scheduling
      mechanism supported by the link, as defined in Section 4.

      Maximum Reservable Burst: includes the maximum reservable burst
      (MRBur) corresponding to the specific scheduling mechanism type
      with variable size, depending on the ST.

      -  If ST is one of ATS, CBS, ATS+CBS, or gLBF, the field size is
         n*4 bytes, and it contains the MRBur per traffic class (4
         bytes, in the unit of bytes), from traffic class 0 to traffic
         class n-1.

      -  If ST is CQF/ECQF, the field size is n*6 bytes, and it contains
         n tuple <cycle duration(2B), MRBur(4B)>, where, cycle duration
         in the unit of microseconds, and MRBur in the unit of bytes.
         Note that MRBur represents the resources of the entire CQF
         instance, not the resources of a specific cycle (or bin) under
         that instance (e.g., a CQF instance may configure 3-bin mode,
         with bin a, b, c).

      -  If ST is EDF, the field size is n*6 bytes, and it contains n
         tuple <delay level(2B), MRBur(4B)>, where, delay level in the
         unit of microseconds, and MRBur in the unit of bytes.  Note
         that all delay levels' maximum reservable burst must meet the
         schedulability condition equation.

      -  If ST is TQF, the field size is n*8 bytes, and it contains n
         tuple <OPL(4B), MRBur(4B)>, where, OPL (Orchestration Period
         Length) in the unit of microseconds, and MRBur in the unit of
         bytes.  Note that MRBur represents resources for individual
         timeslot within the Orchestration Period, and in general all
         timeslots have the same MRBur value.

      -  If ST is C-SCORE, the field size is 4 bytes, and it contains
         the MRBur in the unit of bytes.

   For each scheduling mechanism enabled on the link, the DetNet Maximum
   Reservable Burst Sub-TLV SHOULD be advertised once at most.  A router
   receiving multiple DetNet Maximum Reservable Burst Sub-TLVs for the
   same link and same scheduling mechanism, SHOULD select the first
   advertisement in the lowest-numbered LSP.





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8.  ISIS Advertisement of DetNet Unreserved Burst

   A new IS-IS sub-TLV is defined: the DetNet Unreserved Burst Sub-TLV,
   which is advertised within TLV-22, 222, 23, 223, 141, 25.  For each
   link, multiple DetNet Unreserved Burst Sub-TLVs can be included,
   depending on how many scheduling mechanisms are enabled on the link.

   The following format is defined for the DetNet Unreserved Burst Sub-
   TLV:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type        |     Length    |       ST      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Unreserved Burst (variable)              //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                                  Figure 5

   where:

      Type: TBD.

      Length: variable, depending on size of the Unreserved Burst field.

      ST(Scheduling Type): 1 byte, represents the type of scheduling
      mechanism supported by the link, as defined in Section 4.

      Unreserved Burst: includes the unreserved burst (UBur)
      corresponding to the specific scheduling mechanism type with
      variable size, depending on the ST.

      -  If ST is one of ATS, CBS, ATS+CBS, or gLBF, the field size is
         n*4 bytes, and it contains the UBur per traffic class (4 bytes,
         in the unit of bytes), from traffic class 0 to traffic class
         n-1.

      -  If ST is CQF/ECQF, the field size is n*6 bytes, and it contains
         n tuple <cycle duration(2B), UBur(4B)>, where, cycle duration
         in the unit of microseconds, and UBur in the unit of bytes.
         Note that UBur represents the resources of the entire CQF
         instance, not the resources of a specific cycle (or bin) under
         that instance (e.g., a CQF instance may configure 3-bin mode,
         with bin a, b, c).





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      -  If ST is EDF, the field size is n*6 bytes, and it contains n
         tuple <delay level(2B), UBur(4B)>, where, delay level in the
         unit of microseconds, and UBur in the unit of bytes.

      -  If ST is TQF, the field size is 4+k*6 bytes, and it contains
         OPL(4B) and k (k <= N) tuple <timeslot id(2B), UBur(4B)>,
         where, OPL (Orchestration Period Length) in the unit of
         microseconds, and UBur in the unit of bytes.  Note that UBur
         represents resources for individual timeslot within the
         Orchestration Period.

      -  If ST is C-SCORE, the field size is 4 bytes, and it contains
         the UBur in the unit of bytes.

   For each scheduling mechanism enabled on the link, the DetNet
   Unreserved Burst Sub-TLV SHOULD be advertised once at most, except
   that TQF may advertise multiple DetNet Unreserved Burst Sub-TLVs each
   for a set of timeslots.  A router receiving multiple DetNet
   Unreserved Burst Sub-TLVs for the same link and same scheduling
   mechanism (and same timeslot id in the case of TQF scheduling type),
   SHOULD select the first advertisement in the lowest-numbered LSP.

9.  OSPF Advertisement of Link Deterministic Resource

   Provided in next versions.

10.  Announcement Suppression

   To prevent oscillations and unnecessary advertisements,
   implementations MUST comply with the requirements found in sections 5
   and 6 of [RFC8570] regarding announcement thresholds, filters, and
   suppression.

11.  IANA Considerations

   TBD

12.  Security Considerations

   This document introduces no new security issues.  Security of routing
   within a domain is already addressed as part of the routing protocols
   themselves.  This document proposes no changes to those security
   architectures.

   The authentication methods described in [RFC5304] and [RFC5310] for
   IS-IS, [RFC2328] and [RFC7474] for OSPFv2 and [RFC5340] and [RFC4552]
   for OSPFv3 SHOULD be used to prevent attacks on the IGPs.




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13.  Acknowledgements

   TBD.

14.  References

14.1.  Normative References

   [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>.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328,
              DOI 10.17487/RFC2328, April 1998,
              <https://www.rfc-editor.org/info/rfc2328>.

   [RFC4552]  Gupta, M. and N. Melam, "Authentication/Confidentiality
              for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
              <https://www.rfc-editor.org/info/rfc4552>.

   [RFC5304]  Li, T. and R. Atkinson, "IS-IS Cryptographic
              Authentication", RFC 5304, DOI 10.17487/RFC5304, October
              2008, <https://www.rfc-editor.org/info/rfc5304>.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, DOI 10.17487/RFC5310, February
              2009, <https://www.rfc-editor.org/info/rfc5310>.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
              <https://www.rfc-editor.org/info/rfc5340>.

   [RFC7474]  Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
              "Security Extension for OSPFv2 When Using Manual Key
              Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
              <https://www.rfc-editor.org/info/rfc7474>.

   [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>.

   [RFC8570]  Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
              D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
              Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March
              2019, <https://www.rfc-editor.org/info/rfc8570>.




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   [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>.

   [RFC9330]  Briscoe, B., Ed., De Schepper, K., Bagnulo, M., and G.
              White, "Low Latency, Low Loss, and Scalable Throughput
              (L4S) Internet Service: Architecture", RFC 9330,
              DOI 10.17487/RFC9330, January 2023,
              <https://www.rfc-editor.org/info/rfc9330>.

14.2.  Informative References

   [ATSplusCBS]
              "Latency and Backlog Bounds in Time-Sensitive Networking
              with Credit Based Shapers and Asynchronous Traffic
              Shaping", 2018,
              <https://ieeexplore.ieee.org/document/8493026>.

   [I-D.eckert-detnet-glbf]
              Eckert, T. T., Clemm, A., Bryant, S., and S. Hommes,
              "Deterministic Networking (DetNet) Data Plane - guaranteed
              Latency Based Forwarding (gLBF) for bounded latency with
              low jitter and asynchronous forwarding in Deterministic
              Networks", Work in Progress, Internet-Draft, draft-eckert-
              detnet-glbf-03, 5 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-eckert-
              detnet-glbf-03>.

   [I-D.joung-detnet-stateless-fair-queuing]
              Joung, J., Ryoo, J., Cheung, T., Li, Y., and P. Liu,
              "Latency Guarantee with Stateless Fair Queuing", Work in
              Progress, Internet-Draft, draft-joung-detnet-stateless-
              fair-queuing-03, 2 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-joung-detnet-
              stateless-fair-queuing-03>.

   [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-13, 19 November 2024,
              <https://datatracker.ietf.org/doc/html/draft-peng-detnet-
              deadline-based-forwarding-13>.

   [I-D.peng-detnet-packet-timeslot-mechanism]
              Peng, S., Liu, P., Basu, K., Liu, A., Yang, D., and G.
              Peng, "Timeslot Queueing and Forwarding Mechanism", Work



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              in Progress, Internet-Draft, draft-peng-detnet-packet-
              timeslot-mechanism-10, 27 November 2024,
              <https://datatracker.ietf.org/doc/html/draft-peng-detnet-
              packet-timeslot-mechanism-10>.

   [IEEE802.1Qav]
              "IEEE Standard for Local and metropolitan area networks --
              Virtual Bridged Local Area Networks - Amendment 12:
              Forwarding and Queuing Enhancements for Time-Sensitive
              Streams", 2010,
              <https://ieeexplore.ieee.org/document/8684664>.

   [IEEE802.1Qch]
              "IEEE Standard for Local and metropolitan area networks --
              Bridges and Bridged Networks - Amendment 29: Cyclic
              Queuing and Forwarding", 2017,
              <https://ieeexplore.ieee.org/document/7961303>.

   [IEEE802.1Qcr]
              "IEEE Standard for Local and Metropolitan Area Networks--
              Bridges and Bridged Networks Amendment 34:Asynchronous
              Traffic Shaping", 2020,
              <https://ieeexplore.ieee.org/document/9253013>.

   [IEEE802.1Qdv]
              "Draft Standard for Local and metropolitan area networks--
              Enhancements to Cyclic Queuing and Forwarding", 2023,
              <https://1.ieee802.org/tsn/802-1qdv/>.

   [Net-Calculus]
              "Network Calculus: A Theory of Deterministic Queuing
              Systems for the Internet", 2001,
              <https://leboudec.github.io/netcal/latex/netCalBook.pdf>.

Author's Address

   Shaofu Peng
   ZTE
   China
   Email: peng.shaofu@zte.com.cn











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