



PCE                                                             Q. Xiong
Internet-Draft                                                   S. Peng
Intended status: Standards Track                         ZTE Corporation
Expires: 23 October 2026                                       V. Beeram
                                                        Juniper Networks
                                                                 T. Saad
                                                           Cisco Systems
                                                            M. Koldychev
                                                       Ciena Corporation
                                                           21 April 2026


 Path Computation Element Communication Protocol (PCEP) Extensions for
                            Topology Filter
                   draft-xpbs-pce-topology-filter-06

Abstract

   A topology filter is a data construct that is used to filter network
   topologies.  The Path Computation Element (PCE) MUST take into
   account the topology related constraints during the path computation.
   This document proposes a set of extensions for Path Computation
   Element Communication Protocol (PCEP) to support the topology filter.

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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 23 October 2026.

Copyright Notice

   Copyright (c) 2026 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Topology Filter with PCE  . . . . . . . . . . . . . . . . . .   4
   3.  PCEP Extensions . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  TOPOLOGY-FILTER Object  . . . . . . . . . . . . . . . . .   4
       3.1.1.  IGP Domain Identifier . . . . . . . . . . . . . . . .   5
         3.1.1.1.  Protocol ID TLV . . . . . . . . . . . . . . . . .   5
         3.1.1.2.  Multi-topology ID TLV . . . . . . . . . . . . . .   6
         3.1.1.3.  Algorithm ID TLV  . . . . . . . . . . . . . . . .   7
         3.1.1.4.  Domain ID TLV . . . . . . . . . . . . . . . . . .   7
       3.1.2.  TE Topology Identifier  . . . . . . . . . . . . . . .   7
         3.1.2.1.  Provider ID TLV . . . . . . . . . . . . . . . . .   7
         3.1.2.2.  Client ID TLV . . . . . . . . . . . . . . . . . .   8
         3.1.2.3.  Topology ID TLV . . . . . . . . . . . . . . . . .   8
       3.1.3.  NRP TLV . . . . . . . . . . . . . . . . . . . . . . .   8
       3.1.4.  Filtering Rules TLV . . . . . . . . . . . . . . . . .   9
         3.1.4.1.  Link ID sub-TLV . . . . . . . . . . . . . . . . .   9
         3.1.4.2.  Admin Group sub-TLV . . . . . . . . . . . . . . .  10
         3.1.4.3.  Source Protocol sub-TLV . . . . . . . . . . . . .  10
     3.2.  Procedures  . . . . . . . . . . . . . . . . . . . . . . .  11
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
     4.1.  TOPOLOGY-FILTER Object  . . . . . . . . . . . . . . . . .  11
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   6.  Operational Considerations  . . . . . . . . . . . . . . . . .  13
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     8.1.  Infomative References . . . . . . . . . . . . . . . . . .  13
     8.2.  Normative References  . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16










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1.  Introduction

   [RFC5440] describes the Path Computation Element Computation 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.

   A PCE may perform path computation based on the network topology
   information collected through BGP-LS [RFC9552] or YANG [RFC8776].  It
   can get multiple link-state data from multiple IGP instance, or
   multiple virtual topologies from a single IGP instance.  In other
   cases, as per [I-D.ietf-teas-yang-topology-filter], a path may be
   computed within a network topology such as a specified topology, a
   topology associated with a specific IGP domain, a topology learnt
   from a specific TE information source, a topology defined by the
   application of one or more topology filters, a topology associated
   with an Network Resource Partition (NRP) as per [RFC9543] and so on.
   The PCE MUST take the topology related constraints into consideration
   during the path computation.

   As defined in [I-D.ietf-teas-yang-topology-filter], a topology filter
   is a data construct that is used to filter network topologies.  This
   document proposes a set of extensions for PCEP to support the
   topology filter during path computation.

1.1.  Terminology

   The terminology is defined as [RFC5440], [RFC9552] and [RFC8795].

1.2.  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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2.  Topology Filter with PCE

   As defined in [I-D.ietf-teas-yang-topology-filter], a topology filter
   specifies the topology reference or a set of filtering rules.  The
   topology filters carry a list of topology filters and a topology
   filter-set constitutes a list of topology filter references.

   The topology reference indicates a predefined TE topology or a
   specific IGP domain.  A TE topology can be identified from a global
   scope such as a Provider ID, a Client ID, a Topology ID as per
   [RFC8776].  A logical topology can also be associated with an NRP as
   per [RFC9543] and an NRP can be identified using NRP Identifier (NRP-
   ID) as per [I-D.ietf-teas-ns-ip-mpls].  An IGP domain has a unique
   IGP representation by using the combination of Area-ID, Router-ID,
   Protocol-ID, Multi-Topology Identifier (MT-ID), and BGP-LS Instance-
   ID as per [RFC9552].  The PCE should consider these identifiers as
   topology constraints during path computation.

   The filtering rules specify a set of constraints on the topology
   including include-any, include-all and exclude.  A set of attributes
   that can be used as rules to filter the topology such as link
   affinity, link name, node prefix, AS number and TE information
   source.  The filtering rules of these attributes can be used to
   compute path at PCE.

3.  PCEP Extensions

3.1.  TOPOLOGY-FILTER Object

   This document defines a new TOPOLOGY-FILTER object to carry the
   topology filter.  The TOPOLOGY-FILTER object is optional and
   specifies the specific topology to be taken into account by the PCE
   during path computation.

   TOPOLOGY-FILTER Object-Class is TBD1.

   TOPOLOGY-FILTER Object-Type is TBD2.

   The format of the TOPOLOGY-FILTER object body is:












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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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               Reserved                        |     Flags     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                      Optional TLVs                          //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 1: TOPOLOGY-FILTER Body Object Format

   Reserved (24 bits): This field MUST be set to zero on transmission
   and MUST be ignored on receipt.

   Flags (8 bits): No flags are currently defined.  Unassigned flags
   MUST be set to zero on transmission and MUST be ignored on receipt.

   The format of optional TLVs is defined in [RFC5440] and may be used
   to carry topology filter information as defined in section.  The
   existing topology constraints TLVs could also be reused such as
   Algorithm ID TLV and Domain ID TLV.

3.1.1.  IGP Domain Identifier

   A specific IGP domain can be identified by a combination of Protocol
   ID, Instance ID, MT-ID as per [RFC9552] and Division ID as per
   [RFC8685] and Algorithm ID as per [I-D.ietf-pce-sid-algo].  This
   document defines some TLVs for topology filter to identify an IGP
   domain within a referenced topology.  The Protocol ID TLV is
   mandatory to identify an IGP domain and others are optional to carry
   the additional information to further filter permitted resources
   within the domain.  These TLVs can be carried but each type can only
   be presented once.  And it MUST be applied to filter the resources
   that match all presenting TLVs at the same time.

3.1.1.1.  Protocol ID TLV

   The Protocol ID TLV is mandatory to identify an IGP domain and it is
   defined to carry the Protocol ID and Instance ID.

   The format of the Protocol ID TLV is :









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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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         Type=TBD3             |            Length=12          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Protocol-ID  |                  Reserved                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Instance-ID                           |
       |                         (64 bits)                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                         Figure 2: Protocol ID TLV

   The code point for the TLV type is TBD3.  The TLV length is 12
   octets.

   Protocol-ID (8 bits): defined in [RFC9552] section 5.2.

   Instance-ID (64 bits): defined in [RFC9552] section 5.2.

   Reserved: This fields MUST be set to zero on transmission and MUST be
   ignored on receipt.

3.1.1.2.  Multi-topology ID TLV

   The Multi-topology ID TLV is optional and is defined to carry the MT-
   ID.

   The format of the Multi-topology ID TLV is :


       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=TBD4             |            Length=4           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |R R R R|   Multi-Topology-ID   |          Reserved             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                      Figure 3: Multi-topology ID TLV

   The code point for the TLV type is TBD4.  The TLV length is 4 octets.

   Multi-Topology-ID (12 bits): it indicates the IS-IS MT-ID as defined
   in Sections 7.1 and 7.2 of [RFC5120] or the OSPF MT-ID as defined in
   Section 3.7 of [RFC4915].



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   Reserved (16 bits): This field MUST be set to zero on transmission
   and MUST be ignored on receipt.

3.1.1.3.  Algorithm ID TLV

   The Algorithm ID TLV is optional and is defined to carry the
   Algorithm-ID.

   The Algorithm ID TLV MAY be inserted so as to provide the Flex-algo
   plane information for the computed path.  The format of the TLV is
   defined in [I-D.ietf-pce-sid-algo] section 4.4.

3.1.1.4.  Domain ID TLV

   The Domain ID TLV is optional and is defined to carry the Domain-ID.

   The Domain ID TLV MAY be inserted so as to identify the domains
   served by the PCE.  The format of the TLV is defined in [RFC8685]
   section 3.2.2.

3.1.2.  TE Topology Identifier

   This document defines some TE Topology Identifier TLVs for topology
   filter to identify a predefined TE topology within a referenced
   topology.

3.1.2.1.  Provider ID TLV

   The Provider ID TLV is optional and the format is as following shown:


       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=TBD5             |            Length=4           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Provider-ID                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                         Figure 4: Provider ID TLV

   The code point for the TLV type is TBD5.  The TLV length is 4 octets.

   Provider-ID (32 bits): an identifier to uniquely identify a provider
   as defined in [RFC8776].




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3.1.2.2.  Client ID TLV

   The Client ID TLV is optional and the format is as following shown:


       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=TBD6             |            Length=4           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Client-ID                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                          Figure 5: Client ID TLV

   The code point for the TLV type is TBD6.  The TLV length is 4 octets.

   Client-ID (32 bits): an identifier to uniquely identify a client as
   defined in [RFC8776].

3.1.2.3.  Topology ID TLV

   The Topology ID TLV is optional and the format is as following shown:


       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=TBD7             |            Length=4           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Topology-ID                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                         Figure 6: Topology ID TLV

   The code point for the TLV type is TBD7.  The TLV length is 4 octets.

   Topology-ID (32 bits): an identifier for a topology as defined in
   [RFC8776].

3.1.3.  NRP TLV

   The NRP TLV is optional and is defined to carry the NRP-ID to filter
   the NRP topology.




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   The NRP TLV MAY be inserted so as to provide the NRP information for
   the computed path.  The format of the TLV is defined in
   [I-D.ietf-pce-pcep-nrp] section 2.1.

3.1.4.  Filtering Rules TLV

   This document defines a new Filtering Rules TLV for topology filter
   to carry a set of constrains on the topology by include-any, include-
   all and exclude.

   The Filtering Rules TLV is optional and the format is as following
   shown :


       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=TBD8        |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Exclude-any                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Include-any                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Include-all                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                     Optional sub-TLVs                        //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                     Figure 7: Filtering Rules TLV

   The code point for the TLV type is TBD8.  The TLV length is variable.

   The fields of Exclude-any, Include-any and Include-all are identical
   to the fields of the LSPA object as per [RFC5440] and the SESSION-
   ATTRIBUTE object as per [RFC3209].

   The sub-TLVs carry the attributes that can be used as rules to filter
   the topology and some sub-TLVs are defined in the following sections.

3.1.4.1.  Link ID sub-TLV

   The Link ID is used to identify the link that is used during the path
   calculation.

   The Link ID sub-TLV is defined:



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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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type=TBD9   |     Length    |         Reserved              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Link-ID                                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                         Figure 8: Link ID sub-TLV

   The code point for the TLV type is TBD9.  The TLV length is 6 octets.

   Link-ID (32bits ): defined in IS-IS [RFC5307] and OSPF [RFC3630].

3.1.4.2.  Admin Group sub-TLV

   The Admin Group is used to include the links that is used during the
   path calculation.

       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=TBD10   |     Length    |         Reserved              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Extended Admin Group                     |
      +-                                                             -+
      |                            ...                                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 9: Admin Group sub-TLV

   The code point for the sub-TLV type is TBD10.  The length is
   variable.

   Extended Administrative Group: Extended Administrative Group as
   defined in [RFC7308].

3.1.4.3.  Source Protocol sub-TLV

   The format of the Source Protocol sub-TLV is:











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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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Type=TBD11    |     Length    |   Reserved    | Protocol-ID  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          Instance-ID                          |
       |                           (64 bits)                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



                     Figure 10: Source Protocol sub-TLV

   The code point for the TLV type is TBD11.  The TLV length is 10
   octets.

   Protocol-ID (8 bits): defined in [RFC9552] section 5.2.

   Instance-ID (64 bits): defined in [RFC9552] section 5.2.

3.2.  Procedures

   The TOPOLOGY-FILTER object can be carried within a PCReq message, or
   a PCRep message in case of unsuccessful path computation.  In this
   unsuccessful case, the PCRep message also contains a NO-PATH object,
   and the TOPOLOGY-FILTER object is used to indicate the set of
   topology constriants that could not be satisfied.

   A PCC MAY insert a TOPOLOGY-FILTER object in PCReq message to
   indicate the specific topology that MUST be considered by the PCE
   during path computation.  The PCE will compute the path with the
   constrains with the filtering rules and reply the result to the PCC
   with a PCRep message.

   The PCE could perform path computation based on the topology
   identified by the topology filter rules that can be applied on either
   the native topology or a user specified topology.  The absence of the
   IGP Domain Identifier TLV and TE Topology Identifier TLV indicate
   that the PCE should compute within a native topology and only
   Filtering Rules TLV is applied as the filtering rules.

4.  IANA Considerations

4.1.  TOPOLOGY-FILTER Object

   IANA is requested to make allocations for Topology Filter Object from
   the registry, as follows:




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   TOPOLOGY-FILTER Object-Class is TBD1.

   TOPOLOGY-FILTER Object-Type is TBD2.

   The TLVs for Topology Filter Object is as follows:

            +======+=======================+=================+
            | Type |          TLV          |    Reference    |
            +======+=======================+=================+
            | TBD3 |    Protocol ID TLV    | [this document] |
            +------+-----------------------+-----------------+
            | TBD4 | Multi-topology ID TLV | [this document] |
            +------+-----------------------+-----------------+
            | TBD5 |    Provider ID TLV    | [this document] |
            +------+-----------------------+-----------------+
            | TBD6 |     Client ID TLV     | [this document] |
            +------+-----------------------+-----------------+
            | TBD7 |    Topology ID TLV    | [this document] |
            +------+-----------------------+-----------------+
            | TBD8 |  Filtering Rules TLV  | [this document] |
            +------+-----------------------+-----------------+

                 Table 1: TLVs for Topology Filter Object

   IANA is requested to make allocations for sub-TLVs from the Filtering
   Rules TLV registry, as follows:

      +=======+==================================+=================+
      |  Type | sub-TLVs for Filtering Rules TLV |    Reference    |
      +=======+==================================+=================+
      |  TBD9 |         Link ID sub-TLV          | [this document] |
      +-------+----------------------------------+-----------------+
      | TBD10 |       Admin Group sub-TLV        | [this document] |
      +-------+----------------------------------+-----------------+
      | TBD11 |     Source Protocol sub-TLV      | [this document] |
      +-------+----------------------------------+-----------------+

                            Table 2: Sub-TLVs

5.  Acknowledgements

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








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6.  Operational Considerations

   A PCEP implementation MAY allow the capability of supporting the PCEP
   extensions introduced in this document.  All manageability and
   operational requirements and considerations listed in [RFC5440] and
   [RFC8231], apply to this document.

   The PCEP extensions defined in this document do not impose any new
   requirements on other protocols but rely on the topology information
   from IGP, BGP-LS or YANG data model.

   A PCEP implementation supporting this document SHOULD allow the
   operator to view the topology filter capability defined in this
   document.  and take the topology constraints into account during the
   path computation especially the topology filtering rules which is
   defined in [I-D.ietf-teas-yang-topology-filter].

   The PCEP YANG module is defined in [I-D.ietf-pce-pcep-yang].  In
   future, this YANG module should be extended or augmented to provide
   the additional information relating to topology filter.

7.  Security Considerations

   This document defines a new Topology Filter Object, which do not
   introduce any new security considerations beyond those already listed
   in [RFC4655], [RFC5440], [RFC8231], [RFC8685] and
   [I-D.ietf-pce-sid-algo].

   The security considerations described in [RFC8795] and
   [I-D.ietf-teas-yang-topology-filter] apply to the topology filter
   described in this document as well.

8.  References

8.1.  Infomative References

   [I-D.ietf-pce-pcep-yang]
              Dhody, D., Beeram, V. P., Hardwick, J., and J. Tantsura,
              "A YANG Data Model for Path Computation Element
              Communications Protocol (PCEP)", Work in Progress,
              Internet-Draft, draft-ietf-pce-pcep-yang-30, 26 January
              2025, <https://datatracker.ietf.org/doc/html/draft-ietf-
              pce-pcep-yang-30>.

   [I-D.ietf-teas-ns-ip-mpls]
              Saad, T., Beeram, V. P., Dong, J., Halpern, J. M., and S.
              Peng, "Realizing Network Slices in IP/MPLS Networks", Work
              in Progress, Internet-Draft, draft-ietf-teas-ns-ip-mpls-



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              07, 28 February 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-ns-
              ip-mpls-07>.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
              <https://www.rfc-editor.org/info/rfc3209>.

   [RFC9543]  Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S.,
              Makhijani, K., Contreras, L., and J. Tantsura, "A
              Framework for Network Slices in Networks Built from IETF
              Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024,
              <https://www.rfc-editor.org/info/rfc9543>.

8.2.  Normative References

   [I-D.ietf-pce-pcep-nrp]
              Dong, J., Fang, S., Xiong, Q., Peng, S., Han, L., Wang,
              M., Beeram, V. P., and T. Saad, "Path Computation Element
              Communication Protocol (PCEP) Extensions for Network
              Resource Partition (NRP)", Work in Progress, Internet-
              Draft, draft-ietf-pce-pcep-nrp-00, 6 November 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-pce-
              pcep-nrp-00>.

   [I-D.ietf-pce-sid-algo]
              Sidor, S., Rose, Z., Peng, S., Peng, S., and A. Stone,
              "Carrying SR-Algorithm in Path Computation Element
              Communication Protocol (PCEP)", Work in Progress,
              Internet-Draft, draft-ietf-pce-sid-algo-29, 15 October
              2025, <https://datatracker.ietf.org/doc/html/draft-ietf-
              pce-sid-algo-29>.

   [I-D.ietf-teas-yang-topology-filter]
              Beeram, V. P., Saad, T., Gandhi, R., and X. Liu, "YANG
              Data Model for Topology Filter", Work in Progress,
              Internet-Draft, draft-ietf-teas-yang-topology-filter-02,
              19 October 2025, <https://datatracker.ietf.org/doc/html/
              draft-ietf-teas-yang-topology-filter-02>.

   [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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   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              DOI 10.17487/RFC3630, September 2003,
              <https://www.rfc-editor.org/info/rfc3630>.

   [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>.

   [RFC5307]  Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions
              in Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008,
              <https://www.rfc-editor.org/info/rfc5307>.

   [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>.

   [RFC7308]  Osborne, E., "Extended Administrative Groups in MPLS
              Traffic Engineering (MPLS-TE)", RFC 7308,
              DOI 10.17487/RFC7308, July 2014,
              <https://www.rfc-editor.org/info/rfc7308>.

   [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>.






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   [RFC8685]  Zhang, F., Zhao, Q., Gonzalez de Dios, O., Casellas, R.,
              and D. King, "Path Computation Element Communication
              Protocol (PCEP) Extensions for the Hierarchical Path
              Computation Element (H-PCE) Architecture", RFC 8685,
              DOI 10.17487/RFC8685, December 2019,
              <https://www.rfc-editor.org/info/rfc8685>.

   [RFC8776]  Saad, T., Gandhi, R., Liu, X., Beeram, V., and I. Bryskin,
              "Common YANG Data Types for Traffic Engineering",
              RFC 8776, DOI 10.17487/RFC8776, June 2020,
              <https://www.rfc-editor.org/info/rfc8776>.

   [RFC8795]  Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
              O. Gonzalez de Dios, "YANG Data Model for Traffic
              Engineering (TE) Topologies", RFC 8795,
              DOI 10.17487/RFC8795, August 2020,
              <https://www.rfc-editor.org/info/rfc8795>.

   [RFC9552]  Talaulikar, K., Ed., "Distribution of Link-State and
              Traffic Engineering Information Using BGP", RFC 9552,
              DOI 10.17487/RFC9552, December 2023,
              <https://www.rfc-editor.org/info/rfc9552>.

Authors' Addresses

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


   Shaofu Peng
   ZTE Corporation
   No.50 Software Avenue
   Nanjing
   Jiangsu, 210012
   China
   Email: peng.shaofu@zte.com.cn


   Vishnu Pavan Beeram
   Juniper Networks
   Email: vbeeram@juniper.net


   Tarek Saad
   Cisco Systems
   Email: tsaad.net@gmail.com



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   Mike Koldychev
   Ciena Corporation
   Email: mkoldych@ciena.com
















































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