PCE Working Group C. Li Internet-Draft Huawei Technologies Intended status: Standards Track S. Sivabalan Expires: August 26, 2021 Ciena Corporation S. Peng Huawei Technologies M. Koldychev Cisco Systems, Inc. L. Ndifor MTN Cameroon February 22, 2021 A YANG Data Model for Segment Routing (SR) Policy and SRv6 support in Path Computation Element Communications Protocol (PCEP) draft-li-pce-pcep-srv6-yang-03 Abstract This document augments a YANG data model for the management of Path Computation Element Communications Protocol (PCEP) for communications between a Path Computation Client (PCC) and a Path Computation Element (PCE), or between two PCEs in support for Segment Routing in IPv6 (SRv6) and SR Policy. The data model includes configuration data and state data (status information and counters for the collection of statistics). Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on August 26, 2021. Li, et al. Expires August 26, 2021 [Page 1] Internet-Draft PCEP-SRv6-YANG February 2021 Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 3. Terminology and Notation . . . . . . . . . . . . . . . . . . 3 3.1. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Prefixes in Data Node Names . . . . . . . . . . . . . . . 4 4. The Design of YANG Data Model . . . . . . . . . . . . . . . . 5 4.1. The Overview of PCEP SRv6 Data Model . . . . . . . . . . 5 4.2. The Overview of PCEP SR Policy Data Model . . . . . . . . 5 5. The YANG Modules . . . . . . . . . . . . . . . . . . . . . . 6 5.1. ietf-pcep-srv6 module . . . . . . . . . . . . . . . . . . 6 5.2. ietf-pcep-srpolicy module . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 9.1. Normative References . . . . . . . . . . . . . . . . . . 15 9.2. Informative References . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 1. Introduction The Path Computation Element (PCE) defined in [RFC4655] is an entity that is capable of computing a network path or route based on a network graph, and applying computational constraints. A Path Computation Client (PCC) may make requests to a PCE for paths to be computed. PCEP is the communication protocol between a PCC and PCE and is defined in [RFC5440]. PCEP interactions include path computation requests and path computation replies as well as notifications of specific states related to the use of a PCE in the context of Li, et al. Expires August 26, 2021 [Page 2] Internet-Draft PCEP-SRv6-YANG February 2021 Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering (TE). [RFC8231] specifies extensions to PCEP to enable stateful control of MPLS TE LSPs. [I-D.ietf-pce-segment-routing-ipv6] extends [RFC8664] to support SR for IPv6 data plane. [I-D.ietf-pce-pcep-yang] defines a YANG [RFC7950] data model for the management of PCEP speakers. This document contains a specification of the PCEP-SRv6 YANG module, "ietf-pcep-srv6" which provides the PCEP-SRv6 [I-D.ietf-pce-segment-routing-ipv6] data model. This document also contain the PCEP-SRPolicy YANG module, "ietf-pcep- srpolicy" which provides a reference to SR Policy [I-D.ietf-spring-segment-routing-policy]. The PCEP operational state is included in the same tree as the PCEP configuration consistent with Network Management Datastore Architecture (NMDA) [RFC8342]. The origin of the data is indicated as per the origin metadata annotation. 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. 3. Terminology and Notation This document also uses the following terms defined in [RFC7420]: o PCEP entity: a local PCEP speaker. o PCEP peer: to refer to a remote PCEP speaker. o PCEP speaker: where it is not necessary to distinguish between local and remote. Further, this document also uses the following terms defined in [RFC8231] : o Stateful PCE, Passive Stateful PCE, Active Stateful PCE o Delegation, Revocation, Redelegation o LSP State Report, Path Computation Report message (PCRpt). Li, et al. Expires August 26, 2021 [Page 3] Internet-Draft PCEP-SRv6-YANG February 2021 o LSP State Update, Path Computation Update message (PCUpd). [RFC8281] : o PCE-initiated LSP, Path Computation LSP Initiate Message (PCInitiate). [RFC8408] : o Path Setup Type (PST). [RFC8664] : o Segment Routing (SR). [I-D.ietf-pce-segment-routing-ipv6] : o Segment Routing in IPv6 (SRv6). [I-D.ietf-spring-segment-routing-policy] : o SR Policy. 3.1. Tree Diagrams A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these diagrams is defined in [RFC8340]. 3.2. Prefixes in Data Node Names In this document, names of data nodes and other data model objects are often used without a prefix, as long as it is clear from the context in which YANG module each name is defined. Otherwise, names are prefixed using the standard prefix associated with the corresponding YANG module, as shown in Table 1. +------------+-----------------+----------------------------------+ | Prefix | YANG module | Reference | +------------+-----------------+----------------------------------+ | te-types | ietf-te-types | [RFC8776] | | pcep | ietf-pcep | [I-D.ietf-pce-pcep-yang] | | srv6-types | ietf-srv6-types | [I-D.ietf-spring-srv6-yang] | | sr-policy | ietf-sr-policy | [I-D.ietf-spring-sr-policy-yang] | | rt | ietf-routing | [RFC8349] | +------------+-----------------+----------------------------------+ Table 1: Prefixes and corresponding YANG modules Li, et al. Expires August 26, 2021 [Page 4] Internet-Draft PCEP-SRv6-YANG February 2021 4. The Design of YANG Data Model 4.1. The Overview of PCEP SRv6 Data Model The PCEP-SRv6 YANG module defined in this document has all the common building blocks for the PCEP-SRv6 extension. module: ietf-pcep-srv6 augment /pcep:pcep/pcep:entity/pcep:capability: +--rw srv6 {srv6}? +--rw enabled? boolean +--rw msd-limit? boolean +--rw srv6-msd* [msd-type] +--rw msd-type uint8 +--rw msd-value? uint8 augment /pcep:pcep/pcep:entity/pcep:peers/pcep:peer /pcep:capability: +--rw srv6 {srv6}? +--rw enabled? boolean +--rw msd-limit? boolean +--rw srv6-msd* [msd-type] +--rw msd-type uint8 +--rw msd-value? uint8 augment /pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp: +--ro srv6 {srv6}? +--ro segment-list +--ro segment* [index] +--ro index uint32 +--ro sid-value? srv6-types:srv6-sid 4.2. The Overview of PCEP SR Policy Data Model The PCEP-SRPolicy YANG module defined in this document has all the common building blocks for the PCEP-SR Policy extension. module: ietf-pcep-srpolicy augment /pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp: +--ro sr-policy +--ro color? leafref +--ro endpoint? leafref +--ro protocol-origin? leafref +--ro originator? leafref +--ro discriminator? leafref The sr-policy container is applicable for both SR-MPLS and SRv6. Li, et al. Expires August 26, 2021 [Page 5] Internet-Draft PCEP-SRv6-YANG February 2021 5. The YANG Modules 5.1. ietf-pcep-srv6 module RFC Ed.: In this section, replace all occurrences of 'XXXX' with the actual RFC number and all occurrences of the revision date below with the date of RFC publication (and remove this note). file "ietf-pcep-srv6@2021-02-22.yang" module ietf-pcep-srv6 { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-pcep-srv6"; prefix pcep-srv6; import ietf-srv6-types { prefix srv6-types; reference "I-D.ietf-spring-srv6-yang: YANG Data Model for SRv6 Base and Static"; } import ietf-te-types { prefix te-types; reference "RFC 8776: Common YANG Data Types for Traffic Engineering"; } import ietf-pcep { prefix pcep; reference "I-D.ietf-pce-pcep-yang: A YANG Data Model for Path Computation Element Communications Protocol (PCEP)"; } organization "IETF PCE (Path Computation Element) Working Group"; contact "WG Web: WG List: Editor: Cheng Li "; description "The YANG module augments the PCEP YANG operational model with SRv6. Copyright (c) 2021 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or Li, et al. Expires August 26, 2021 [Page 6] Internet-Draft PCEP-SRv6-YANG February 2021 without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2021-02-22 { description "Initial revision."; reference "RFC XXXX: A YANG Data Model for Segment Routing (SR) Policy and SRv6 support in Path Computation Element Communications Protocol (PCEP)"; } /* Features */ feature srv6 { description "Support Segment Routing in IPv6 (SRv6) for PCE."; reference "I-D.ietf-pce-segment-routing-ipv6: PCEP Extensions for Segment Routing leveraging the IPv6 data plane"; } /* Identity */ identity path-setup-srv6 { if-feature "srv6"; base te-types:path-signaling-type; description "SRv6 path setup type"; } /* Groupings */ grouping srv6-msd { description "SRv6 MSD"; leaf msd-type { type uint8; description "SRv6 Maximum Segment Depth (MSD) Type"; } leaf msd-value { type uint8; Li, et al. Expires August 26, 2021 [Page 7] Internet-Draft PCEP-SRv6-YANG February 2021 description "SRv6 MSD value for the type"; } } grouping srv6 { description "SRv6"; container srv6 { if-feature "srv6"; description "If SRv6 is supported"; leaf enabled { type boolean; description "Enabled or Disabled"; } leaf msd-limit { type boolean; default "false"; description "True indicates no limit on MSD, the list srv6-msd is ignored"; } list srv6-msd { key "msd-type"; description "list of SRv6 MSD"; uses srv6-msd; } } } grouping segment-list { description "Segment list grouping"; container segment-list { description "Segments for given segment list"; list segment { key "index"; description "Configure Segment/hop at the index"; uses segment-properties; } } } Li, et al. Expires August 26, 2021 [Page 8] Internet-Draft PCEP-SRv6-YANG February 2021 grouping segment-properties { description "Segment properties grouping"; leaf index { type uint32; description "Segment index"; } leaf sid-value { type srv6-types:srv6-sid; description "SRv6 SID value"; } } /* * Augment modules to add SRv6 */ augment "/pcep:pcep/pcep:entity/pcep:capability" { description "Augmenting SRv6"; uses srv6; } augment "/pcep:pcep/pcep:entity/pcep:peers/pcep:peer/pcep:capability" { description "Augmenting SRv6"; uses srv6; } augment "/pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp" { description "Augmenting SRv6"; container srv6 { when "derived-from-or-self (/pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp/pcep:pst, 'path-setup-srv6')" { description "For SRv6 path"; } if-feature "srv6"; uses segment-list; description "SRv6"; } Li, et al. Expires August 26, 2021 [Page 9] Internet-Draft PCEP-SRv6-YANG February 2021 } } 5.2. ietf-pcep-srpolicy module RFC Ed.: In this section, replace all occurrences of 'XXXX' with the actual RFC number and all occurrences of the revision date below with the date of RFC publication (and remove this note). file "ietf-pcep-srpolicy@2021-02-22.yang" module ietf-pcep-srpolicy { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-pcep-srpolicy"; prefix pcep-srp; import ietf-pcep { prefix pcep; reference "I-D.ietf-pce-pcep-yang: A YANG Data Model for Path Computation Element Communications Protocol (PCEP)"; } import ietf-sr-policy { prefix sr-policy; reference "I-D.ietf-spring-sr-policy-yang: YANG Data Model for Segment Routing Policy"; } import ietf-routing { prefix rt; reference "RFC 8349: A YANG Data Model for Routing Management"; } organization "IETF PCE (Path Computation Element) Working Group"; contact "WG Web: WG List: Editor: Cheng Li "; description "The YANG module augments the PCEP YANG operational model with SRv6. Copyright (c) 2021 IETF Trust and the persons identified as authors of the code. All rights reserved. Li, et al. Expires August 26, 2021 [Page 10] Internet-Draft PCEP-SRv6-YANG February 2021 Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2021-02-22 { description "Initial revision."; reference "RFC XXXX: A YANG Data Model for Segment Routing (SR) Policy and SRv6 support in Path Computation Element Communications Protocol (PCEP)"; } /* Groupings */ grouping sr-policy { description "Segment Routing Policy grouping"; // Editor's Note - headend is missig in SR Policy // Yang mode leaf color { type leafref { path "/rt:routing/sr-policy:segment-routing/" + "sr-policy:traffic-engineering/sr-policy:" + "policies/sr-policy:policy/sr-policy:" + "color"; } description "SR Policy Color"; reference "I-D.ietf-spring-segment-routing-policy: Segment Routing Policy Architecture"; } leaf endpoint { type leafref { path "/rt:routing/sr-policy:segment-routing/" + "sr-policy:traffic-engineering/sr-policy:" + "policies/sr-policy:policy/sr-policy:" + "endpoint"; } description "SR Policy Endpoint"; reference Li, et al. Expires August 26, 2021 [Page 11] Internet-Draft PCEP-SRv6-YANG February 2021 "I-D.ietf-spring-segment-routing-policy: Segment Routing Policy Architecture"; } leaf protocol-origin { type leafref { path "/rt:routing/sr-policy:segment-routing/" + "sr-policy:traffic-engineering/sr-policy:" + "policies/sr-policy:policy/sr-policy:" + "candidate-paths/sr-policy:" + "candidate-path/sr-policy:protocol-origin"; } must '(. = "pcep")' { error-message "The protocol origin must be PCEP"; } description "SR Policy Candidate Path Protocol"; reference "I-D.ietf-spring-segment-routing-policy: Segment Routing Policy Architecture"; } leaf originator { type leafref { path "/rt:routing/sr-policy:segment-routing/" + "sr-policy:traffic-engineering/sr-policy:" + "policies/sr-policy:policy/sr-policy:" + "candidate-paths/sr-policy:" + "candidate-path/sr-policy:originator"; } description "SR Policy Candidate Path Originator"; reference "I-D.ietf-spring-segment-routing-policy: Segment Routing Policy Architecture"; } leaf discriminator { type leafref { path "/rt:routing/sr-policy:segment-routing/" + "sr-policy:traffic-engineering/sr-policy:" + "policies/sr-policy:policy/sr-policy:" + "candidate-paths/sr-policy:" + "candidate-path/sr-policy:discriminator"; } description "SR Policy Candidate Path Discriminator"; reference "I-D.ietf-spring-segment-routing-policy: Segment Routing Policy Architecture"; } Li, et al. Expires August 26, 2021 [Page 12] Internet-Draft PCEP-SRv6-YANG February 2021 } augment "/pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp" { description "Augmenting SR Policy"; container sr-policy { when "derived-from-or-self (/pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp/pcep:pst, 'path-setup-sr') or derived-from-or-self (/pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp/pcep:pst, 'path-setup-srv6')" { description "Applicable for SR or SRv6"; } uses sr-policy; description "SR Policy"; } } } 6. Security Considerations The YANG module defined in this document is designed to be accessed via network management protocol such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer and the mandatory-to-implement secure transport is SSH [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446] The NETCONF access control model [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a pre- configured subset of all available NETCONF or RESTCONF protocol operations and content. There are a number of data nodes defined in the YANG module which are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., ) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability: /pcep:pcep/pcep:entity/pcep:capability/pcep-srv6:srv6 - configure local SRv6 capability and parameters. Li, et al. Expires August 26, 2021 [Page 13] Internet-Draft PCEP-SRv6-YANG February 2021 /pcep:pcep/pcep:entity/pcep:peers/pcep:peer/pcep:capability/pcep- srv6:srv6 - configure peer's SRv6 capability and parameters. Unauthorized access to above list can adversely affect the PCEP session between the local entity and the peers. This may lead to inability to compute new paths, stateful operations on the delegated as well as PCE-initiated LSPs. Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability: /pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp/pcep-srv6:srv6 - The SRv6 SID in the network. Unauthorized access to this could provide entire path and network usage information. /pcep:pcep/pcep:entity/pcep:lsp-db/pcep:lsp/pcep-srpolicy:sr- policy - The reference to SR Policy. Unauthorized access to this could provide SR Policy usage information. 7. IANA Considerations This document registers a URI in the "IETF XML Registry" [RFC3688]. Following the format in RFC 3688, the following registration has been made. URI: urn:ietf:params:xml:ns:yang:ietf-pcep-srv6 Registrant Contact: The PCE WG of the IETF. XML: N/A; the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-pcep-srpolicy Registrant Contact: The PCE WG of the IETF. XML: N/A; the requested URI is an XML namespace. This document registers a YANG module in the "YANG Module Names" registry [RFC6020]. Li, et al. Expires August 26, 2021 [Page 14] Internet-Draft PCEP-SRv6-YANG February 2021 Name: ietf-pcep-srv6 Namespace: urn:ietf:params:xml:ns:yang:ietf-pcep-srv6 Prefix: pcep-srv6 Reference: This I-D Name: ietf-pcep-srpolicy Namespace: urn:ietf:params:xml:ns:yang:ietf-pcep-srpolicy Prefix: pcep-srp Reference: This I-D 8. Acknowledgements The authors would like to thank Dhruv Dhody for the initial YANG model. 9. References 9.1. 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, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . Li, et al. Expires August 26, 2021 [Page 15] Internet-Draft PCEP-SRv6-YANG February 2021 [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . [RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for Routing Management (NMDA Version)", RFC 8349, DOI 10.17487/RFC8349, March 2018, . [RFC8408] Sivabalan, S., Tantsura, J., Minei, I., Varga, R., and J. Hardwick, "Conveying Path Setup Type in PCE Communication Protocol (PCEP) Messages", RFC 8408, DOI 10.17487/RFC8408, July 2018, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . Li, et al. Expires August 26, 2021 [Page 16] Internet-Draft PCEP-SRv6-YANG February 2021 [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, . [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, . [I-D.ietf-spring-srv6-yang] Raza, K., Agarwal, S., Liu, X., Hu, Z., Hussain, I., Shah, H., Voyer, D., Matsushima, S., Horiba, K., Abdelsalam, A., and J. Rajamanickam, "YANG Data Model for SRv6 Base and Static", draft-ietf-spring-srv6-yang-00 (work in progress), September 2020. [I-D.ietf-pce-pcep-yang] Dhody, D., Hardwick, J., Beeram, V., and J. Tantsura, "A YANG Data Model for Path Computation Element Communications Protocol (PCEP)", draft-ietf-pce-pcep- yang-15 (work in progress), October 2020. [I-D.ietf-pce-segment-routing-ipv6] Li, C., Negi, M., Sivabalan, S., Koldychev, M., Kaladharan, P., and Y. Zhu, "PCEP Extensions for Segment Routing leveraging the IPv6 data plane", draft-ietf-pce- segment-routing-ipv6-08 (work in progress), November 2020. [I-D.ietf-spring-sr-policy-yang] Raza, K., Sawaya, R., Shunwan, Z., Voyer, D., Durrani, M., Matsushima, S., and V. Beeram, "YANG Data Model for Segment Routing Policy", draft-ietf-spring-sr-policy- yang-00 (work in progress), September 2020. 9.2. Informative References [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006, . [RFC7420] Koushik, A., Stephan, E., Zhao, Q., King, D., and J. Hardwick, "Path Computation Element Communication Protocol (PCEP) Management Information Base (MIB) Module", RFC 7420, DOI 10.17487/RFC7420, December 2014, . Li, et al. Expires August 26, 2021 [Page 17] Internet-Draft PCEP-SRv6-YANG February 2021 [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, . [I-D.ietf-spring-segment-routing-policy] Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", draft- ietf-spring-segment-routing-policy-09 (work in progress), November 2020. Authors' Addresses Cheng Li Huawei Technologies Huawei Campus, No. 156 Beiqing Rd. Beijing 100095 China EMail: c.l@huawei.com Siva Sivabalan Ciena Corporation EMail: ssivabal@ciena.com Shuping Peng Huawei Technologies Huawei Campus, No. 156 Beiqing Rd. Beijing 100095 China EMail: pengshuping@huawei.com Mike Koldychev Cisco Systems, Inc. EMail: mkoldych@cisco.com Luc-Fabrice Ndifor MTN Cameroon Cameroon EMail: Luc-Fabrice.Ndifor@mtn.com Li, et al. Expires August 26, 2021 [Page 18]