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PCEP Extension for Bounded Latency
draft-xiong-pce-detnet-bounded-latency-04

Document Type Active Internet-Draft (individual)
Authors Quan Xiong , Peng Liu , Rakesh Gandhi
Last updated 2024-02-28
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draft-xiong-pce-detnet-bounded-latency-04
PCE                                                        Q. Xiong, Ed.
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                                  P. Liu
Expires: 31 August 2024                                     China Mobile
                                                               R. Gandhi
                                                     Cisco Systems, Inc.
                                                        28 February 2024

                   PCEP Extension for Bounded Latency
               draft-xiong-pce-detnet-bounded-latency-04

Abstract

   In certain networks, such as Deterministic Networking (DetNet), it is
   required to consider the bounded latency for path selection.  This
   document describes the extensions for Path Computation Element
   Communication Protocol (PCEP) to carry deterministic latency
   constraints and distribute deterministic paths for end-to-end path
   computation in deterministic services.

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
   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 31 August 2024.

Copyright Notice

   Copyright (c) 2024 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 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
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  PCEP Extensions . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  METRIC Object . . . . . . . . . . . . . . . . . . . . . .   4
       3.1.1.  End-to-End Bounded Delay Metric . . . . . . . . . . .   4
       3.1.2.  End-to-End Bounded Jitter Metric  . . . . . . . . . .   4
     3.2.  LSP Object  . . . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Deterministic Path ERO Subobject  . . . . . . . . . . . .   5
       3.3.1.  Deadline Information  . . . . . . . . . . . . . . . .   6
       3.3.2.  Cycle Information . . . . . . . . . . . . . . . . . .   7
       3.3.3.  Timeslot Information  . . . . . . . . . . . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  New Metric Types  . . . . . . . . . . . . . . . . . . . .   8
     5.2.  New LSP-EXTENDED-FLAG Flag Registry . . . . . . . . . . .   8
     5.3.  New ERO Subobject . . . . . . . . . . . . . . . . . . . .   9
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   [RFC5440] describes the Path Computation Element Protocol (PCEP)
   which is used between a Path Computation Element (PCE) and a Path
   Computation Client (PCC) (or other PCE) to enable computation of
   Multi-protocol Label Switching (MPLS) for Traffic Engineering Label
   Switched Path (TE LSP).  PCEP Extensions for the Stateful PCE Model
   [RFC8231] describes a set of extensions to PCEP to enable active
   control of MPLS-TE and Generalized MPLS (GMPLS) tunnels.  As depicted
   in [RFC4655], a PCE MUST be able to compute the path of a TE LSP by
   operating on the TED and considering bandwidth and other constraints
   applicable to the TE LSP service request.  The constraint parameters
   are provided such as metric, bandwidth, delay, affinity, etc.
   However these parameters can't meet the DetNet requirements.

   According to [RFC8655], Deterministic Networking (DetNet) operates at
   the IP layer and delivers service which provides extremely low data
   loss rates and bounded latency within a network domain.  The bounded
   latency indicates the minimum and maximum end-to-end latency from
   source to destination and bounded jitter (packet delay variation).

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   [I-D.ietf-detnet-scaling-requirements]has described the enhanced
   requirements for DetNet enhanced data plane including the
   deterministic latency guarantees and information used by functions
   ensuring deterministic latency should be supported.  A common data
   fields can be defined as per [I-D.xiong-detnet-data-fields-edp] and a
   Deterministic Latency Action (DLA) option has been proposed to carry
   queuing-based metadata.  The computing method of end-to-end delay
   bounds is defined in [RFC9320].  It is the sum of the 6 delays in
   DetNet bounded latency model.  And these delays should be measured
   and collected by IGP, but the related mechanisms are out of this
   document.  The end-to-end delay bounds can also be computed as the
   sum of non queuing delay bound and queuing delay bound along the
   path.  The upper bounds of non queuing delay are constant and depend
   on the specific network and the value of queuing delay bound depends
   on the queuing mechanisms deployed along the path.

   As per [I-D.ietf-detnet-controller-plane-framework], explicit path
   should be calculated and established in control plane to guarantee
   the deterministic transmission.  The corresponding IS-IS and OSPF
   extensions are specified in
   [I-D.peng-lsr-deterministic-traffic-engineering].  When the PCE is
   deployed, the path computation should be applicable for deterministic
   networks.  It is required that bounded latency including minimum and
   maximum end-to-end latency and bounded delay variation are considered
   during the deterministic path selection for PCE.  The bounded latency
   constraints should be extended for PCEP.  Moreover, the information
   along the deterministic path should be provided to the PCC after the
   path computation such as queuing parameters.

   This document describes the extensions for PCEP to carry
   deterministic latency constraints and distribute deterministic paths
   for end-to-end path computation in deterministic services.

1.1.  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 RFC 2119 [RFC2119].

2.  Terminology

   The terminology is defined as [RFC8655] and [RFC5440].

3.  PCEP Extensions

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3.1.  METRIC Object

   The METRIC object is defined in Section 7.8 of [RFC5440], comprising
   metric-value and metric-type (T field), and a flags field, comprising
   a number of bit flags (B bit and C bit).  This document defines two
   types for the METRIC object.

3.1.1.  End-to-End Bounded Delay Metric

   [RFC8233] has proposed the Path Delay metric type of the METRIC
   object to represent the sum of the Link Delay metric of all links
   along a P2P path.  This document proposes the End-to-End Bounded
   Delay metric in PCEP to represent the sum of Output delay, Link
   delay, Frame preemption delay, Processing delay, Regulation delay and
   Queuing delay as defined in [RFC9320] along a deterministic path.  Or
   the End-to-End Bounded Delay metric can be encoded as the sum of non
   queuing delay bound and queuing delay bound along the deterministic
   path.  The extensions for End-to-End Bounded Delay Metric are as
   following shown:

   *  T=TBD1: End-to-End Bounded Delay Metric.

   *  The value of End-to-End Bounded Delay Metric is the encoding in
      units of microseconds with 32 bits.

   *  The B bit MUST be set to suggest a maximum bound for the end-to-
      end delay of deterministic path.  The end-to-end delay must be
      less than or equal to the value.

   A PCC MAY use the End-to-End Bounded Latency metric in a Path
   Computation Request (PCReq) message to request a deterministic path
   meeting the end-to-end latency requirement.  A PCE MAY use the End-
   to-End Bounded Latency metric in a Path Computation Reply (PCRep)
   message along with a NO-PATH object in the case where the PCE cannot
   compute a path meeting this constraint.  A PCE can also use this
   metric to send the computed end-to-end bounded latency to the PCC.

3.1.2.  End-to-End Bounded Jitter Metric

   [RFC8233] has proposed the Path Delay Variation metric type of the
   METRIC object to represent the sum of the Link Delay Variation metric
   of all links along the path.  This document proposes the End-to-End
   Bounded Jitter metric in PCEP to represent the difference between the
   end-to-end upper bounded latency and the end-to-end lower bounded
   latency along a deterministic path.  The extensions for End-to-End
   Bounded Jitter Metric are as following shown:

   *  T=TBD2: End-to-End Bounded Jitter Metric.

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   *  The value of End-to-End Bounded Jitter Metric is the encoding in
      units of microseconds with 32 bits.

   *  The B bit MUST be set to suggest a maximum bound for the end-to-
      end jitter of deterministic path.  The end-to-end jitter must be
      less than or equal to the value.

   A PCC MAY use the End-to-End Bounded Jitter metric in a PCReq message
   to request a deterministic path meeting the end-to-end delay
   variation requirement.  A PCE MAY use the End-to-End Bounded Jitter
   metric in a PCRep message along with a NO-PATH object in the case
   where the PCE cannot compute a path meeting this constraint.  A PCE
   can also use this metric to send the computed end-to-end bounded
   Jitter to the PCC.

3.2.  LSP Object

   The LSP Object is defined in Section 7.3 of [RFC8231].  This document
   defines a new flag (D-flag) to present the deterministic path for the
   LSP-EXTENDED-FLAG TLV carried in LSP Object as defined in [RFC9357].

   D (Request for Deterministic Path) : If the bit is set to 1, it
   indicates that the PCC requests PCE to compute the deterministic
   path.  A PCE would also set this bit to 1 to indicate that the
   deterministic path is included by PCE and encoded in the PCRep, PCUpd
   or PCInitiate message.

3.3.  Deterministic Path ERO Subobject

   As defined in [RFC9320], the end-to-end delay bounds can be presented
   as the sum of non queuing delay bound and queuing delay bound along
   the path.  The upper bounds of non queuing delay are constant and
   depend on the specific network, but the value of queuing delay bound
   depends on the queuing mechanisms deployed along the deterministic
   path.  [I-D.xiong-detnet-data-fields-edp] and a Deterministic Latency
   Action (DLA) option has been proposed to carry the queuing
   information.  So to meet the requirements of the end-to-end delay,
   the PCE should select a path with a specific queuing mechanism and
   configure the related parameters to the PCC.  And the PCC may insert
   the queuing-based information into the packet headers.

   The ERO specified in [RFC5440] can be used to carry deterministic
   path information.  In order to carry deterministic latency Action
   Information such as queuing information, this document defines a new
   ERO subobject referred to as the Deterministic Path ERO subobject
   (DP-ERO).  An ERO carrying a deterministic path consists of one or
   more ERO subobjects, and it MUST carry DP-ERO subobjects.

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   An DP-ERO subobject is formatted as 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |L|  Type=TBD3  |     Length    |     Class     |    DLA Type   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      //                DLA Information(variable, optional)          //
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 1: DP-ERO Subobject Format

   L (1bit): The L bit is an attribute of the subobject.  The L bit is
   set if the subobject represents a loose hop in the explicit route.
   If the bit is not set, the subobject represents a strict hop in the
   explicit route.

   Type (8bits): Set to TBD3.

   Length (8bits): Contains the total length of the subobject in octets.
   The Length MUST be at least 8 and MUST be a multiple of 4.

   Class (8bits): indicates the deterministic forwarding class.

   DLA Type (8bits): indicates the type of DLA information.

   DLA Information (variable): indicates the corresponding Deterministic
   Latency Action parameters.  The format depends on the value in the
   DLA type and the following sections shows the examples of the DLA
   information.

3.3.1.  Deadline Information

   When the DLA Type is deadline-based queuing mechanisms, it should
   carry deadline information for the DP-ERO subobject.  For example,
   the deadline-based queuing mechanism has been proposed in
   [I-D.stein-srtsn] and [I-D.peng-detnet-deadline-based-forwarding].
   The deadlines parameters along the path should be computed at PCE and
   configured to the PCC, and then inserted into the packet headers.
   The format of the deadline information is shown as following figure.

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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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Deadline                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 2: Deadline Information

   Deadline (32bits): indicates the deadline or budget delay for a node
   to forward a flow.

3.3.2.  Cycle Information

   When the DLA Type is cyclic-based queuing mechanisms, it should carry
   Cycle information for the DP-ERO subobject.  For example, the cyclic-
   based queuing mechanism has been proposed in [IEEE802.1Qch] and
   improved in [I-D.chen-detnet-sr-based-bounded-latency].  The cycle
   parameters along the path should be computed at PCE and configured to
   the PCC, and then inserted into the packet headers.  The format of
   the cycle information is shown as 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Cycle Profile ID                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Cycle ID                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                        Figure 3: Cycle Information

   Cycle Profile ID (32bits): indicates the profile number which the
   cyclic queue applied at a node.

   Cycle ID (32bits): indicates the clycle number for a node to forward
   a flow.

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3.3.3.  Timeslot Information

   When the DLA Type is timeslot-based queuing mechanisms, it should
   carry timeslot information for the DP-ERO subobject.  For example,
   the timeslot-based queuing mechanism has been proposed in
   [I-D.peng-detnet-packet-timeslot-mechanism].  The timeslot parameters
   along the path should be computed at PCE and configured to the PCC,
   and then inserted into the packet headers.  The format of the
   timeslot information is shown as 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Timeslot ID                            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 4: Timeslot Information

   Timeslot ID (32bits): indicates the timeslot number for a node to
   forward a flow.

4.  Security Considerations

   TBA

5.  IANA Considerations

5.1.  New Metric Types

   This document defines two new metric type for the PCEP.  IANA is
   requested to allocate the following codepoint in the PCEP "METRIC
   Object T Field" registry:

        Value     Description                        Reference
        ------    -------------------------------    -------------
        TBD1      End-to-End Bounded Delay Metric    This document
        TBD2      End-to-End Bounded Jitter Metric   This document

5.2.  New LSP-EXTENDED-FLAG Flag Registry

   [RFC9357] defines the LSP-EXTENDED-FLAG TLV.  IANA is requested to
   make allocations from the Flag field registry, as follows:

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        Bit       Description                       Reference
        ------    ------------------------------    -------------
        D flag    Request for Deterministic Path    This document

5.3.  New ERO Subobject

   This document defines a new subobject type for the PCEP explicit
   route object (ERO).  The code points for subobject types of these
   objects is maintained in the RSVP parameters registry, under the
   EXPLICIT_ROUTE objects.  IANA is requested to confirm the following
   allocations in the RSVP Parameters registry for each of the new
   subobject types defined in this document.

      Object                Subobject                  Subobject Type
      --------------        ---------------------      ---------------
      EXPLICIT_ROUTE        DP-ERO (PCEP-specific)     TBD3

6.  Acknowledgements

   The authors would like to thank Dhruv Dhody, Andrew Stone, Lou
   Berger, Janos Farkas for their review, suggestions and comments to
   this document.

7.  References

7.1.  Normative References

   [I-D.chen-detnet-sr-based-bounded-latency]
              Chen, M., Geng, X., Li, Z., Joung, J., and J. Ryoo,
              "Segment Routing (SR) Based Bounded Latency", Work in
              Progress, Internet-Draft, draft-chen-detnet-sr-based-
              bounded-latency-03, 7 July 2023,
              <https://datatracker.ietf.org/doc/html/draft-chen-detnet-
              sr-based-bounded-latency-03>.

   [I-D.ietf-detnet-controller-plane-framework]
              Malis, A. G., Geng, X., Chen, M., Qin, F., Varga, B., and
              C. J. Bernardos, "Deterministic Networking (DetNet)
              Controller Plane Framework", Work in Progress, Internet-
              Draft, draft-ietf-detnet-controller-plane-framework-05, 26
              September 2023, <https://datatracker.ietf.org/doc/html/
              draft-ietf-detnet-controller-plane-framework-05>.

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   [I-D.ietf-detnet-scaling-requirements]
              Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
              zhushiyin, and X. Geng, "Requirements for Scaling
              Deterministic Networks", Work in Progress, Internet-Draft,
              draft-ietf-detnet-scaling-requirements-05, 20 November
              2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
              detnet-scaling-requirements-05>.

   [I-D.ietf-pce-segment-routing-ipv6]
              Li, C., Kaladharan, P., Sivabalan, S., Koldychev, M., and
              Y. Zhu, "Path Computation Element Communication Protocol
              (PCEP) Extensions for Segment Routing leveraging the IPv6
              dataplane", Work in Progress, Internet-Draft, draft-ietf-
              pce-segment-routing-ipv6-22, 15 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-pce-
              segment-routing-ipv6-22>.

   [I-D.joung-detnet-asynch-detnet-framework]
              Joung, J., Ryoo, J., Cheung, T., Li, Y., and P. Liu,
              "Asynchronous Deterministic Networking Framework for
              Large-Scale Networks", Work in Progress, Internet-Draft,
              draft-joung-detnet-asynch-detnet-framework-03, 19
              September 2023, <https://datatracker.ietf.org/doc/html/
              draft-joung-detnet-asynch-detnet-framework-03>.

   [I-D.peng-6man-deadline-option]
              Peng, S., Tan, B., and P. Liu, "Deadline Option", Work in
              Progress, Internet-Draft, draft-peng-6man-deadline-option-
              01, 11 July 2022, <https://datatracker.ietf.org/doc/html/
              draft-peng-6man-deadline-option-01>.

   [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-08, 14 December 2023,
              <https://datatracker.ietf.org/doc/html/draft-peng-detnet-
              deadline-based-forwarding-08>.

   [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
              in Progress, Internet-Draft, draft-peng-detnet-packet-
              timeslot-mechanism-05, 14 December 2023,
              <https://datatracker.ietf.org/doc/html/draft-peng-detnet-
              packet-timeslot-mechanism-05>.

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   [I-D.peng-lsr-deterministic-traffic-engineering]
              Peng, S., "IGP Extensions for Deterministic Traffic
              Engineering", Work in Progress, Internet-Draft, draft-
              peng-lsr-deterministic-traffic-engineering-01, 4 July
              2023, <https://datatracker.ietf.org/doc/html/draft-peng-
              lsr-deterministic-traffic-engineering-01>.

   [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>.

   [I-D.xiong-detnet-data-fields-edp]
              Xiong, Q., Liu, A., Gandhi, R., and D. Yang, "Data Fields
              for DetNet Enhanced Data Plane", Work in Progress,
              Internet-Draft, draft-xiong-detnet-data-fields-edp-01, 10
              July 2023, <https://datatracker.ietf.org/doc/html/draft-
              xiong-detnet-data-fields-edp-01>.

   [I-D.xiong-detnet-large-scale-enhancements]
              Xiong, Q., Du, Z., Zhao, J., and D. Yang, "Enhanced DetNet
              Data Plane Framework for Scaling Deterministic Networks",
              Work in Progress, Internet-Draft, draft-xiong-detnet-
              large-scale-enhancements-04, 26 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
              large-scale-enhancements-04>.

   [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>.

   [RFC4655]  Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
              Computation Element (PCE)-Based Architecture", RFC 4655,
              DOI 10.17487/RFC4655, August 2006,
              <https://www.rfc-editor.org/info/rfc4655>.

   [RFC4915]  Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
              Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
              RFC 4915, DOI 10.17487/RFC4915, June 2007,
              <https://www.rfc-editor.org/info/rfc4915>.

   [RFC5120]  Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
              Topology (MT) Routing in Intermediate System to
              Intermediate Systems (IS-ISs)", RFC 5120,
              DOI 10.17487/RFC5120, February 2008,
              <https://www.rfc-editor.org/info/rfc5120>.

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   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/info/rfc5440>.

   [RFC6549]  Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
              Instance Extensions", RFC 6549, DOI 10.17487/RFC6549,
              March 2012, <https://www.rfc-editor.org/info/rfc6549>.

   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,
              <https://www.rfc-editor.org/info/rfc7752>.

   [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>.

   [RFC8231]  Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
              Computation Element Communication Protocol (PCEP)
              Extensions for Stateful PCE", RFC 8231,
              DOI 10.17487/RFC8231, September 2017,
              <https://www.rfc-editor.org/info/rfc8231>.

   [RFC8233]  Dhody, D., Wu, Q., Manral, V., Ali, Z., and K. Kumaki,
              "Extensions to the Path Computation Element Communication
              Protocol (PCEP) to Compute Service-Aware Label Switched
              Paths (LSPs)", RFC 8233, DOI 10.17487/RFC8233, September
              2017, <https://www.rfc-editor.org/info/rfc8233>.

   [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>.

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
              DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

   [RFC9320]  Finn, N., Le Boudec, J.-Y., Mohammadpour, E., Zhang, J.,
              and B. Varga, "Deterministic Networking (DetNet) Bounded
              Latency", RFC 9320, DOI 10.17487/RFC9320, November 2022,
              <https://www.rfc-editor.org/info/rfc9320>.

Xiong, et al.            Expires 31 August 2024                [Page 12]
Internet-Draft     PCEP Extension for Bounded Latency      February 2024

   [RFC9357]  Xiong, Q., "Label Switched Path (LSP) Object Flag
              Extension for Stateful PCE", RFC 9357,
              DOI 10.17487/RFC9357, February 2023,
              <https://www.rfc-editor.org/info/rfc9357>.

Authors' Addresses

   Quan Xiong (editor)
   ZTE Corporation
   China
   Email: xiong.quan@zte.com.cn

   Peng Liu
   China Mobile
   Beijing
   China
   Email: liupengyjy@chinamobile.com

   Rakesh Gandhi
   Cisco Systems, Inc.
   Canada
   Email: rgandhi@cisco.com

Xiong, et al.            Expires 31 August 2024                [Page 13]