SPRING Working Group T. Saleh, Ed. Internet-Draft K. Raza Intended status: Standards Track Cisco Systems Expires: 24 November 2026 Z. Shunwan Huawei Technologies S. Matsushima SoftBank V. Beeram Juniper Networks 23 May 2026 YANG Data Model for Segment Routing Policy draft-ietf-spring-sr-policy-yang-07 Abstract This document defines a YANG data model for Segment Routing (SR) Policy that can be used for configuring, instantiating, and managing SR policies. The model is generic and applies equally to the MPLS and SRv6 instantiations of SR policies. 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 24 November 2026. Copyright Notice Copyright (c) 2026 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 Saleh, et al. Expires 24 November 2026 [Page 1] Internet-Draft YANG Data Model for SR Policy May 2026 and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Specification of Requirements . . . . . . . . . . . . . . . . 3 3. Building Blocks . . . . . . . . . . . . . . . . . . . . . . . 3 4. YANG Model . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Prefixes in Data Node Names . . . . . . . . . . . . . . . 5 4.2. Types and Definitions . . . . . . . . . . . . . . . . . . 5 4.3. SR Policy . . . . . . . . . . . . . . . . . . . . . . . . 6 4.3.1. Configuration . . . . . . . . . . . . . . . . . . . . 7 4.3.2. State . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3.3. Notification . . . . . . . . . . . . . . . . . . . . 10 5. Pending Items . . . . . . . . . . . . . . . . . . . . . . . . 10 6. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. YANG Specification . . . . . . . . . . . . . . . . . . . . . 19 7.1. Types . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.2. SR Policy . . . . . . . . . . . . . . . . . . . . . . . . 29 8. Security Considerations . . . . . . . . . . . . . . . . . . . 65 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 66 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 67 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 67 11.1. Normative References . . . . . . . . . . . . . . . . . . 67 11.2. Informative References . . . . . . . . . . . . . . . . . 69 Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 70 1. Introduction The Network Configuration Protocol (NETCONF) [RFC6241] defines mechanisms to manage network devices. YANG [RFC7950] is a modular language that represents data structures in an XML tree format, and is used as a data modeling language for NETCONF. Segment Routing (SR), as defined in [RFC8402], allows a headend node to steer a packet flow along any topological path and/or service chain. The headend node is said to steer a flow into a Segment Routing Policy (SR Policy). An SR policy is a framework that enables instantiation of an ordered list of segments on a node for implementing a policy [RFC9256]. Saleh, et al. Expires 24 November 2026 [Page 2] Internet-Draft YANG Data Model for SR Policy May 2026 This document introduces a YANG data model for SR policy framework for instantiating, configuring and managing SR policies along with its attributes. It is also expected that other companion models, such as BGP SR Policy [I-D.ietf-idr-segment-routing-te-policy], will be defined and/or augmented accordingly in their respective areas. This model defines the following constructs for managing an SR policy: * Configuration * Operational State * Notifications * Executables (Actions) This document expects and requires the reader to be well familiar with the concepts and constructs of an SR policy [RFC9256] as well as the YANG modeling language and its presentation [RFC7950]. This document uses the YANG terminology defined in Section 3 of [RFC7950]. The meanings of the symbols in the YANG module tree diagrams are defined in [RFC8340]. 2. Specification of Requirements 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 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Building Blocks Before looking into the YANG model for SR policy, it is important to recall and highlight the major building blocks and constructs that constitute and contribute to an SR policy, as described in [RFC9256]. * policy: specifies constructs to allow a headend node to setup SR path(s) as an ordered list of segments for a given color and endpoint. The endpoint and the color are used to automate the steering of service or transport routes on an SR Policy. For a given headend, the key for an SR policy is (color, endpoint) where endpoint is an IP address that could be also NULL. Saleh, et al. Expires 24 November 2026 [Page 3] Internet-Draft YANG Data Model for SR Policy May 2026 * candidate-path: is the unit for signalling of an SR Policy to a headend via protocols (such as PCEP, BGP, CLI etc.). A candidate path is either dynamic or explicit type, where an explicit candidate path is associated with one or more segment-lists and dynamic candidate path expresses optimization objectives and set of constraints. An SR Policy is associated with one or more candidate paths and the preference of the candidate path is used to select the best candidate path for an SR Policy. A candidate path is valid if it is usable (e.g. when its constituents SIDs are reachable). An "active" candidate path is the selected path (for forwarding) that is valid and determined to be the best path of the SR Policy. A candidate path is keyed by (protocol-origin, originator, discriminator). * segment-list: specifies ordered list of segments to traverse, where a segment can be specified in various forms (refer section 4 of [RFC9256]). The list is sorted by the index of the segment. A segment-list is used and referred by an explicit type of candidate-path. A segment-list is keyed by its name. * binding-sid: An SR policy is associated with a BSID to provide benefits of scaling, network opacity and service independence. 4. YANG Model The modeling in this document complies with the Network Management Datastore Architecture (NMDA) [RFC8342]. The operational state data is combined with the associated configuration data in the same hierarchy [RFC8407]. When protocol states are retrieved from the NMDA operational state datastore, the returned states cover all "config true" (rw) and "config false" (ro) nodes defined in the schema. For SR policy YANG specification, this document defines following new YANG modules: Saleh, et al. Expires 24 November 2026 [Page 4] Internet-Draft YANG Data Model for SR Policy May 2026 +======================+========================================+ | Module Name | Purpose | +======================+========================================+ | ietf-sr-policy-types | defines common and basic types related | | | to an SR policy and related constructs | +----------------------+----------------------------------------+ +----------------------+----------------------------------------+ | ietf-sr-policy | defines the model for SR policy | | | instantiation, configuration, and | | | management | +----------------------+----------------------------------------+ Table 1 4.1. Prefixes in Data Node Names The tree diagrams and data node names in this document use prefixes from the following external modules. +============+====================+================================+ | Prefix | YANG Module | Reference | +============+====================+================================+ | inet | ietf-inet-types | [RFC6991] | +------------+--------------------+--------------------------------+ | if | ietf-interfaces | [RFC8343] | +------------+--------------------+--------------------------------+ | rt | ietf-routing | [RFC8349] | +------------+--------------------+--------------------------------+ | rt-types | ietf-routing-types | [RFC8294] | +------------+--------------------+--------------------------------+ | srv6-types | ietf-srv6-types | [I-D.ietf-spring-srv6-yang] | +------------+--------------------+--------------------------------+ | te-types | ietf-te-types | [I-D.ietf-teas-rfc8776-update] | +------------+--------------------+--------------------------------+ | yang | ietf-yang-types | [RFC6991] | +------------+--------------------+--------------------------------+ Table 2: Prefixes and Corresponding YANG Modules 4.2. Types and Definitions SR policy common types and definitions are defined in the new module "ietf-sr-policy-types". The main types defined in this module include: * dataplane-type: A union to specify MPLS or IPv6 as the dataplane type for SR. Saleh, et al. Expires 24 November 2026 [Page 5] Internet-Draft YANG Data Model for SR Policy May 2026 * sid-value-type: A Union to specify SID value for SR-MPLS or SRv6 type. * binding-sid-alloc-mode: Enum to define explicit or dynamic alloc mode types for a BSID. * protocol-origin-type: The base identity along with its children specify protocol origin (e.g. PCEP) for an SR policy. * explicit-binding-sid-rule-type: Enum to specify BSID alloc enforcement/rule when doing explicit alloc request. * binding-sid-oper-state: An Enum representing various operational states for a BSID. * policy-admin-state: An Enum for admin state of an SR policy. * policy-oper-state: An Enum for operational state of an SR policy. * segment-type: The base identity along with its children define various types for a "segment" of a Segment list. * candidate-path-not-selected-reason: The base identity along with its children to specify reason for not selecting a candidate path as the best/active path. * policy-down-reason: The base identity along with its children to specify reason for a policy becoming (or remaining) operationally down. * binding-sid-unavailable-reason: The base identity along with its children to specify reason for a BSID's unavailability. The associated YANG specification for this module is captured in Section 7.1. 4.3. SR Policy The base SR policy model is captured in ietf-sr-policy module. This base module augments "/rt:routing" and specifies the configuration, operational state, executables/rpcs, and notification events required to manage SR policies. The associated YANG specification for this module is captured in Section 7.2. Saleh, et al. Expires 24 November 2026 [Page 6] Internet-Draft YANG Data Model for SR Policy May 2026 4.3.1. Configuration In terms of configuration hierarchy, SR policy configuration tree has following three main areas: * optimization-templates: container that defines list of templates per color. The template is used to define a set of optimization objectives and constraints used to instantiate an SR policy on- demand. * attributes: container that defines common constructs that could be used across policies. Examples of such a construct include segment-lists, affinity-map etc. In future revision of this document, it is expected that this container will have more constructs defined. * policies: container that defines list of policies with their attributes such as BSID, candidate-paths etc. Following diagram depicts high level yang organization and hierarchy for an SR policy specification: Saleh, et al. Expires 24 November 2026 [Page 7] Internet-Draft YANG Data Model for SR Policy May 2026 segment-routing traffic-engineering +--rw optimization-templates | +--rw optimization-template* [color] | +--rw color uint32 | +--rw candidate-paths | +--rw candidate-path* [discriminator] | | .... | + attributes | + affinity-map | | .... | | | + segment-lists | | segment-list* [name] | | segments | | segment* [index] | | ... | + explicit-binding-sid-rules | ... | + policies policy* [color endpoint] + ... | + binding-sid | ... | + candidate-paths candidate-path* [protocol-origin originator-asn originator-node-address discriminator] + ... | + type + explicit | segment-lists | segment-list* [ref] | ... + dynamic constraints ... Figure 1: SR Policy - Hierarchy The complete YANG tree can be found in Figure 2. Saleh, et al. Expires 24 November 2026 [Page 8] Internet-Draft YANG Data Model for SR Policy May 2026 Please take note of the following important points regarding the configurations: * This model supports both MPLS and SRv6 dataplane for SR -- i.e. items like segments and BSID can be defined as MPLS label or SRv6 SIDs. * Specification of a segment supports all the types defined in SR policy base specification document * The above model supports explicit BSID specification on SR policy level as the main mode of specification. The model also allows explicit BSID per candidate-path as an if-feature capability that is optional for implementations * The above model will be extended in future revisions of this document to enhance constraints specification for dynamic type of candidate-path, as well as add traffic-steering controls. 4.3.2. State As per NMDA model, the state related to configuration items specified in earlier Section 4.3.1 can be retrieved from the same tree. This section defines the other operational state items related to SR policy. In addition to configured state, the operational state corresponding to the SR policy includes: * policy operational state * policy up/down timestamps * policy BSID info such as alloc mode, actual value in-use, operational state, and forwarding stats * Per candidate-path info such as: - Whether candidate-path is the best candidate-path - In case of non-best, the reason for such non-selection - Type of candidate-path - explicit or dynamic Saleh, et al. Expires 24 November 2026 [Page 9] Internet-Draft YANG Data Model for SR Policy May 2026 - Per segment-list information - such as validity of the segment- list, as well as forwarding state for a valid segment-list. The forwarding state is represented in terms of per forwarding path info that includes nexthop address, outgoing interface, protection information, and encapsulation (label stack or SRv6 SID stack) etc. The complete YANG tree can be found in Figure 2. 4.3.3. Notification This model defines a list of notifications to inform an operator of important events detected regarding an SR policy. These events include events related to: * policy status: policy operational state changes * Candidate-path active status and changes * Explicit Binding SID collision/unavailability events Section 6 captures the YANG tree for the notification. 5. Pending Items Following are the items that will be addressed in future revisions of this document: * Configuration and Specification of: - Traffic steering over SR policy - Spray policy * Executables (RPC actions) 6. YANG Tree Using the building blocks described in Section 3, following is the complete graphical representation of the data model for SR policy: module: ietf-sr-policy augment /rt:routing: +--rw segment-routing +--rw traffic-engineering +--rw optimization-templates | +--rw optimization-template* [color] Saleh, et al. Expires 24 November 2026 [Page 10] Internet-Draft YANG Data Model for SR Policy May 2026 | +--rw color uint32 | +--rw candidate-paths | +--rw candidate-path* [discriminator] | +--rw discriminator uint32 | +--rw optimization-objectives | | +--rw minimize-metric | | +--rw metric-type? identityref | | +--rw margin | | +--rw type? | | | sr-policy-types:margin-type | | +--rw value? uint32 | | +--ro computed-value? uint32 | +--rw constraints | +--rw srlg | | +--rw exclude-any* string | +--rw affinity | | +--rw exclude-any* string | | +--rw include-any* string | | +--rw include-all* string | +--rw ip-address | | +--rw exclude* inet:ip-address | +--rw upper-bounds | | +--rw cumulative-metric | | | +--rw metric-type? identityref | | | +--rw value? uint32 | | +--rw max-sids? uint32 | +--rw segment-rules | | +--rw sid-protection-eligibility? | | sr-policy-types: | | sid-protection-eligibility-type | +--rw max-sids? uint32 +--rw attributes | +--rw segment-lists | | +--rw segment-list* [name] | | +--rw name string | | +--rw segments | | +--rw segment* [index] | | +--rw index uint32 | | +--rw type identityref | | +--rw sr-mpls | | | +--rw Type-A | | | | +--rw value? rt-types:mpls-label | | | +--rw Type-C | | | | +--rw ipv4-address? | | | | | inet:ipv4-address | | | | +--rw algorithm? uint8 | | | +--rw Type-D | | | | +--rw ipv6-address? Saleh, et al. Expires 24 November 2026 [Page 11] Internet-Draft YANG Data Model for SR Policy May 2026 | | | | | inet:ipv6-address | | | | +--rw algorithm? uint8 | | | +--rw Type-E | | | | +--rw ipv4-address? | | | | | inet:ipv4-address | | | | +--rw interface-identifier? uint32 | | | +--rw Type-F | | | | +--rw local-ipv4-address? | | | | | inet:ipv4-address | | | | +--rw remote-ipv4-address? | | | | inet:ipv4-address | | | +--rw Type-G | | | | +--rw local-ipv6-address? | | | | | inet:ipv6-address | | | | +--rw local-interface-identifier? | | | | | uint32 | | | | +--rw remote-ipv6-address? | | | | | inet:ipv6-address | | | | +--rw remote-interface-identifier? | | | | uint32 | | | +--rw Type-H | | | +--rw local-ipv6-address? | | | | inet:ipv6-address | | | +--rw remote-ipv6-address? | | | inet:ipv6-address | | +--rw srv6 | | | +--rw Type-B | | | | +--rw value? | | | | | srv6-types:srv6-sid | | | | +--rw sid-behavior? identityref | | | | +--rw sid-structure | | | | +--rw locator-block-length? | | | | | srv6-types: | | | | | srv6-locator-block-len | | | | +--rw locator-node-length? | | | | | srv6-types: | | | | | srv6-locator-node-len | | | | +--rw function-length? | | | | | srv6-types: | | | | | srv6-sid-func-len | | | | +--rw argument-length? | | | | srv6-types:srv6-sid-arg-len | | | +--rw Type-I | | | | +--rw ipv6-address? | | | | | inet:ipv6-address | | | | +--rw algorithm? uint8 | | | +--rw Type-J | | | | +--rw local-ipv6-address? Saleh, et al. Expires 24 November 2026 [Page 12] Internet-Draft YANG Data Model for SR Policy May 2026 | | | | | inet:ipv6-address | | | | +--rw local-interface-identifier? | | | | | uint32 | | | | +--rw remote-ipv6-address? | | | | | inet:ipv6-address | | | | +--rw remote-interface-identifier? | | | | uint32 | | | +--rw Type-K | | | +--rw local-ipv6-address? | | | | inet:ipv6-address | | | +--rw remote-ipv6-address? | | | inet:ipv6-address | | +--rw validate? boolean | +--rw explicit-binding-sid-rules* [index] | +--rw index uint32 | +--rw rule | sr-policy-types: | explicit-binding-sid-rule-type +--rw policies +--rw policy* [headend color endpoint] +--rw name? sr-policy-types:name-type +--rw headend inet:ip-address +--rw color sr-policy-types:color-type +--rw endpoint inet:ip-address +--rw description? string +--rw admin-state? | sr-policy-types:policy-admin-state +--rw priority? uint8 +--rw profile-id? uint32 +--rw bandwidth | +--rw requested? uint64 | +--ro reserved? uint64 +--ro oper-state? | sr-policy-types:policy-oper-state +--ro transition-count? uint32 +--ro up-time? yang:date-and-time +--ro down-time? yang:date-and-time +--rw binding-sid | +--rw mpls-sid | | +--rw value? | | | sr-policy-types:mpls-sid-value-type | | +--ro alloc-mode? | | | sr-policy-types:binding-sid-alloc-mode | | +--ro allocated-sid? | | | sr-policy-types:sid-value-type | | +--ro oper-state? | | sr-policy-types:binding-sid-oper-state | +--rw srv6-sids Saleh, et al. Expires 24 November 2026 [Page 13] Internet-Draft YANG Data Model for SR Policy May 2026 | +--rw srv6-sid* [index] | +--rw index uint32 | +--rw locator-name? | | srv6-types:srv6-locator-name-type | +--rw value? srv6-types:srv6-sid | +--rw sid-behavior? identityref | +--rw sid-structure | | +--rw locator-block-length? | | | srv6-types:srv6-locator-block-len | | +--rw locator-node-length? | | | srv6-types:srv6-locator-node-len | | +--rw function-length? | | | srv6-types:srv6-sid-func-len | | +--rw argument-length? | | srv6-types:srv6-sid-arg-len | +--ro alloc-mode? | | sr-policy-types: | | binding-sid-alloc-mode | +--ro allocated-sid? | | sr-policy-types:sid-value-type | +--ro oper-state? | sr-policy-types: | binding-sid-oper-state +--ro counters | +--ro pkts? yang:counter64 | +--ro octets? yang:counter64 +--rw candidate-paths +--rw candidate-path* [ protocol-origin originator-asn originator-node-address discriminator] +--rw protocol-origin | identityref +--rw originator-asn uint32 +--rw originator-node-address | sr-policy-types:node-address-type +--rw discriminator uint32 +--rw preference uint32 +--rw name? string +--rw description? string +--rw drop-upon-invalid? boolean +--rw admin-state? boolean +--rw binding-sid | {capability-candidate-path-binding-sid}? | +--rw mpls-sid | | +--rw value? Saleh, et al. Expires 24 November 2026 [Page 14] Internet-Draft YANG Data Model for SR Policy May 2026 | | sr-policy-types: | | mpls-sid-value-type | +--rw srv6-sids | +--rw srv6-sid* [index] | +--rw index uint32 | +--rw locator-name? | | srv6-types: | | srv6-locator-name-type | +--rw value? | | srv6-types:srv6-sid | +--rw sid-behavior? identityref | +--rw sid-structure | +--rw locator-block-length? | | srv6-types: | | srv6-locator-block-len | +--rw locator-node-length? | | srv6-types: | | srv6-locator-node-len | +--rw function-length? | | srv6-types: | | srv6-sid-func-len | +--rw argument-length? | srv6-types:srv6-sid-arg-len +--rw (type)? | +--:(explicit) | | +--rw segment-lists | | +--rw segment-list* [name-ref] | | +--rw name-ref leafref | | +--rw weight? uint32 | | +--ro is-valid? boolean | | +--ro counters | | +--ro pkts? yang:counter64 | | +--ro octets? yang:counter64 | +--:(dynamic) | | +--rw segment-list | | | +--rw segment-list-dataplane-type | | | | sr-policy-types:dataplane-type | | | +--ro is-valid? | | | | boolean | | | +--ro counters | | | +--ro pkts? yang:counter64 | | | +--ro octets? yang:counter64 | | +--rw optimization-objectives | | | +--rw minimize-metric | | | +--rw metric-type? identityref | | | +--rw margin | | | +--rw type? | | | | sr-policy-types: Saleh, et al. Expires 24 November 2026 [Page 15] Internet-Draft YANG Data Model for SR Policy May 2026 | | | | margin-type | | | +--rw value? uint32 | | | +--ro computed-value? uint32 | | +--rw constraints | | +--rw srlg | | | +--rw exclude-any* string | | | +--rw include-any* string | | | +--rw include-all* string | | +--rw affinity | | | +--rw exclude-any* string | | | +--rw include-any* string | | | +--rw include-all* string | | +--rw ip-address | | | +--rw exclude* | | | | inet:ip-address | | | +--rw include-any* | | | | inet:ip-address | | | +--rw include-all* | | | inet:ip-address | | +--rw upper-bounds | | | +--rw cumulative-metric | | | | +--rw metric-type? identityref | | | | +--rw value? uint32 | | | +--rw max-sids? uint32 | | +--rw segment-rules | | | +--rw sid-algorithm? | | | | sr-policy-types: | | | | sid-algorithm-type | | | +--rw sid-protection-eligibility? | | | sr-policy-types: | | | sid-protection- | | | eligibility-type | | +--rw disjoint-path | | | +--rw disjointness-type? | | | | te-types: | | | | te-path-disjointness | | | +--rw association-group-id | | | | uint16 | | | +--rw association-source | | | | inet:ip-address | | | +--rw association-extended-id? | | | yang:hex-string | | +--rw max-sids? uint32 | +--:(composite) | +--rw constituent-policies | +--rw constituent-policy* [color] | +--rw color | | sr-policy-types:color-type Saleh, et al. Expires 24 November 2026 [Page 16] Internet-Draft YANG Data Model for SR Policy May 2026 | +--rw weight? uint32 +--ro is-best-candidate-path? boolean +--ro non-selection-reason? | identityref +--ro is-active? boolean +--ro is-valid? boolean +--ro computed-sid-list | +--ro (dataplane-type)? | +--:(mpls) | | +--ro labels* [index] | | +--ro index uint32 | | +--ro label? rt-types:mpls-label | +--:(srv6) | +--ro sids* [index] | +--ro index uint32 | +--ro sid? srv6-types:srv6-sid +--ro forwarding-paths +--ro forwarding-path* [path-id] +--ro path-id uint8 +--ro next-hop-address? | inet:ip-address +--ro next-hop-table-id? uint32 +--ro interface? | if:interface-ref +--ro is-protected? boolean +--ro backup-path-id? uint8 +--ro is-pure-backup? boolean +--ro weight? uint32 +--ro sid-list | +--ro (dataplane-type)? | +--:(mpls) | | +--ro labels* [index] | | +--ro index uint32 | | +--ro label? | | rt-types:mpls-label | +--:(srv6) | +--ro sids* [index] | +--ro index uint32 | +--ro sid? | srv6-types:srv6-sid +--ro counters +--ro pkts? yang:counter64 +--ro octets? yang:counter64 notifications: +---n sr-policy-oper-state-change-event | +--ro policy-name-ref? leafref | +--ro policy-color-ref? leafref Saleh, et al. Expires 24 November 2026 [Page 17] Internet-Draft YANG Data Model for SR Policy May 2026 | +--ro policy-endpoint-ref? leafref | +--ro policy-new-oper-state? | | sr-policy-types:policy-oper-state | +--ro policy-down-reason? identityref +---n sr-policy-candidate-path-change-event | +--ro policy-name-ref? leafref | +--ro policy-color-ref? leafref | +--ro policy-endpoint-ref? leafref | +--ro existing-preference? uint32 | +--ro new-preference? uint32 +---n sr-policy-binding-sid-unavailable-event | +--ro policy-name-ref? leafref | +--ro policy-color-ref? leafref | +--ro policy-endpoint-ref? leafref | +--ro (dataplane-type)? | | +--:(mpls) | | | +--ro policy-mpls-binding-sid-value-ref? leafref | | | {capability-candidate-path-binding-sid}? | | +--:(srv6) | | +--ro policy-srv6-binding-sid-value-ref? leafref | | {capability-candidate-path-binding-sid}? | +--ro reason? identityref +---n sr-policy-candidate-path-binding-sid-mismatch-event +--ro policy-color-ref? | leafref +--ro policy-endpoint-ref? | leafref +--ro existing-candidate-path-protocol-origin-ref? | leafref +--ro existing-candidate-path-preference-ref? | leafref +--ro (dataplane-type)? | +--:(mpls) | | +--ro existing-candidate-path-mpls-binding-sid-value-ref? | | leafref {capability-candidate-path-binding-sid}? | +--:(srv6) | +--ro existing-candidate-path-srv6-binding-sid-value-ref? | leafref {capability-candidate-path-binding-sid}? +--ro conflicting-candidate-path-protocol-origin? | uint8 +--ro conflicting-candidate-path-preference? | uint32 +--ro conflicting-candidate-path-binding-sid-dataplane? | sr-policy-types:dataplane-type +--ro conflicting-candidate-path-binding-sid-value? sr-policy-types:sid-value-type Figure 2: SR Policy - YANG Tree Saleh, et al. Expires 24 November 2026 [Page 18] Internet-Draft YANG Data Model for SR Policy May 2026 7. YANG Specification Following are actual YANG definition for the modules defined earlier in the document. 7.1. Types This module references [RFC9256]. file "ietf-sr-policy-types@2026-05-23.yang" module ietf-sr-policy-types { namespace "urn:ietf:params:xml:ns:yang:ietf-sr-policy-types"; prefix "sr-policy-types"; import ietf-inet-types { prefix "inet"; } import ietf-routing-types { prefix "rt-types"; } import ietf-srv6-types { prefix "srv6-types"; } organization "IETF SPRING Working Group"; contact "WG Web: WG List: Editor: Kamran Raza Editor: Tarik Saleh Editor: Zhuang Shunwan Editor: Satoru Matsushima Editor: Pavan Vishnu Beeram "; description "This YANG module defines the essential types for the management of SR policy module. Saleh, et al. Expires 24 November 2026 [Page 19] Internet-Draft YANG Data Model for SR Policy May 2026 Copyright (c) 2024 IETF Trust and the persons identified as authors of the code. All rights reserved. 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 Revised 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."; // RFC Editor: replace XXXX with actual RFC number and remove // this note revision "2026-05-23" { description "Remove the metric type definition. The metric type from te-types will be reused instead."; reference "RFC 9256"; } revision "2025-05-22" { // RFC Editor: replace the above date 2025-05-22 with the date of // publication and remove this note. description "Add a type for MPLS SID value"; reference "RFC XXXX: YANG Data Model for Segment-routing Policy Types"; // RFC Editor: replace XXXX with actual RFC number and remove // this note } revision "2024-03-04" { // RFC Editor: replace the above date 2024-03-04 with the date of // publication and remove this note. description "Alignment with SR policy architecture RFC9256"; reference "RFC XXXX: YANG Data Model for Segment-routing Policy Types"; // RFC Editor: replace XXXX with actual RFC number and remove // this note } revision "2022-03-28" { Saleh, et al. Expires 24 November 2026 [Page 20] Internet-Draft YANG Data Model for SR Policy May 2026 description "Alignment with SR policy architecture"; reference "draft-ietf-spring-sr-policy-yang"; } revision "2019-11-04" { description "New editor added"; reference "draft-raza-spring-sr-policy-yang"; } revision "2019-07-08" { description "Dynamic TE candidate-path support"; reference "draft-raza-spring-sr-policy-yang"; } revision "2018-07-01" { description "Initial version"; reference "draft-raza-spring-sr-policy-yang"; } /* Identities */ identity candidate-path-not-selected-reason { description "Base identity for which reasons for not selecting candidate path are derived from"; } identity candidate-path-not-selected-not-best { base candidate-path-not-selected-reason; description "Higher preference path exists"; } identity candidate-path-not-selected-no-valid-segment-list { base candidate-path-not-selected-reason; description "Candidate path has no valid segment list(s)"; } identity candidate-path-not-selected-empty-segment-list { base candidate-path-not-selected-reason; description "Candidate path has empty segment list(s)"; } Saleh, et al. Expires 24 November 2026 [Page 21] Internet-Draft YANG Data Model for SR Policy May 2026 identity candidate-path-not-selected-invalid-binding-sid { base candidate-path-not-selected-reason; description "Candidate path has invalid binding SID"; } identity policy-down-reason { description "Base identity for the reasons why SR policy is operationally down"; } identity policy-down-reason-admin-down { base policy-down-reason; description "Policy is administrately down"; } identity policy-down-reason-no-source-address { base policy-down-reason; description "Policy has no source address"; } identity policy-down-reason-no-endpoint { base policy-down-reason; description "Policy has no end-point"; } identity policy-down-reason-no-candidate-path { base policy-down-reason; description "Policy has no candidate path"; } identity policy-down-reason-no-valid-candidate-path { base policy-down-reason; description "Policy has no valid candidate path"; } identity policy-down-reason-candidate-path-invalid-segment-list { base policy-down-reason; description "Policy's candidate path has invalid segment list"; } identity policy-down-reason-policy-unconfigured { base policy-down-reason; description "Policy is unconfigured"; } identity policy-down-reason-policy-color-endpoint-updated { base policy-down-reason; description "Policy's color and end-point are updated"; } identity policy-down-reason-local-label-setup-failed { base policy-down-reason; description "Policy's local label setup (allocation/rewrite) failed"; } Saleh, et al. Expires 24 November 2026 [Page 22] Internet-Draft YANG Data Model for SR Policy May 2026 identity policy-down-reason-forwarding-rewrite-failed { base policy-down-reason; description "Policy's forwarding rewrite installation failed"; } identity policy-down-reason-internal-error { base policy-down-reason; description "Infra related internal error"; } identity binding-sid-unavailable-reason { description "Base identity for binding sid unavailable reason types"; } identity binding-sid-allocation-error { base binding-sid-unavailable-reason; description "SID allocator returned an error"; } identity binding-sid-already-exists { base binding-sid-unavailable-reason; description "Binding sid already exists/allocated"; } identity binding-sid-internal-error { base binding-sid-unavailable-reason; description "Internal error with binding sid allocation"; } identity binding-sid-color-endpoint-conflict { base binding-sid-unavailable-reason; description "Binding sid already allocated by another sr-policy with different color/endpoint"; } identity binding-sid-rewrite-error { base binding-sid-unavailable-reason; description "Binding sid forwarding rewrite error"; } identity binding-sid-outside-srlb-range { base binding-sid-unavailable-reason; description "Binding sid outside SRLB range"; } identity segment-type { description "Base identity for the segment type"; } identity segment-type-A { base segment-type; description "SR-MPLS Label"; } identity segment-type-B { Saleh, et al. Expires 24 November 2026 [Page 23] Internet-Draft YANG Data Model for SR Policy May 2026 base segment-type; description "SRv6 SID"; } identity segment-type-C { base segment-type; description "IPv4 Prefix with optional SR Algorithm"; } identity segment-type-D { base segment-type; description "IPv6 Global Prefix with optional SR Algorithm for SR-MPLS"; } identity segment-type-E { base segment-type; description "IPv4 Prefix with Local Interface ID"; } identity segment-type-F { base segment-type; description "IPv4 Addresses for link endpoints as Local, Remote pair"; } identity segment-type-G { base segment-type; description "IPv6 Prefix and Interface ID for link endpoints as Local, Remote pair for SR-MPLS"; } identity segment-type-H { base segment-type; description "IPv6 Addresses for link endpoints as Local, Remote pair for SR-MPLS"; } identity segment-type-I { base segment-type; description "IPv6 Global Prefix with optional SR Algorithm for SRv6"; } identity segment-type-J { base segment-type; description "IPv6 Prefix and Interface ID for link endpoints as Local, Remote pair for SRv6"; } identity segment-type-K { base segment-type; description "IPv6 Addresses for link endpoints as Local, Remote pair for Saleh, et al. Expires 24 November 2026 [Page 24] Internet-Draft YANG Data Model for SR Policy May 2026 SRv6"; } identity protocol-origin-type { description "Base identity for originating protocol type"; } identity protocol-origin-type-pcep { base protocol-origin-type; description "PCEP used as signalling mechanism for the candidate path"; } identity protocol-origin-type-bgp { base protocol-origin-type; description "BGP used as signalling mechanism for the candidate path"; } identity protocol-origin-type-local { base protocol-origin-type; description "CLI, Yang model via Netconf, gRPC, etc used for candidate path instantiation"; } /* Typdefs */ typedef mpls-sid-value-type { type rt-types:mpls-label; description "MPLS SID value type"; } typedef sid-value-type { type union { type rt-types:mpls-label; type srv6-types:srv6-sid; } description "The SID value type"; } typedef binding-sid-oper-state { type enumeration { enum ALLOC-PENDING { value 1; description "SID allocation pending for Binding SID"; } enum PROGRAMMED { value 3; description "Binding SID is programmed in forwarding"; } enum CONFLICT { Saleh, et al. Expires 24 November 2026 [Page 25] Internet-Draft YANG Data Model for SR Policy May 2026 value 4; description "Binding SID is in-conflict state with regards to SID allocation. This also means that SID allocation is pending"; } } description "Binding SID operational state type"; } typedef policy-admin-state { type enumeration { enum UP { value 1; description "SR policy is administratively up"; } enum DOWN { value 2; description "SR policy is administratively down"; } } description "SR policy admin state"; } typedef policy-oper-state { type enumeration { enum UP { value 1; description "SR policy is operationally up"; } enum DOWN { value 2; description "SR policy is operationally down"; } } description "SR policy oper state"; } typedef margin-type { type enumeration { enum absolute { value 1; description "Absolute value"; } enum relative { value 2; description "Relative value"; } } description "Margin type"; } typedef dataplane-type { type enumeration { Saleh, et al. Expires 24 November 2026 [Page 26] Internet-Draft YANG Data Model for SR Policy May 2026 enum mpls { value 1; description "Segment-routing MPLS"; } enum srv6 { value 2; description "Segment-routing v6"; } } description "Dataplane type of the segments"; } typedef binding-sid-alloc-mode { type enumeration { enum explicit { value 1; description "Explicitly specified BSID"; } enum dynamic { value 2; description "Dynamically allocated BSID"; } } description "Binding SID allocation mode"; } typedef explicit-binding-sid-rule-type { type enumeration { enum enforce-srlb { value 1; description "Explicit Binding SID is enforced with no fallback if label does not fall in SRLB or if no SRLB is configured"; } enum fallback-dynamic { value 2; description "Explicit Binding SID falls back to dynamic in case explicit label is not available."; } } description "Explicit binding sid rule types"; } typedef sid-protection-eligibility-type { type enumeration { enum protected-preferred { Saleh, et al. Expires 24 November 2026 [Page 27] Internet-Draft YANG Data Model for SR Policy May 2026 value 1; description "Prefer protected SID"; } enum protected-only { value 2; description "Protected SID only"; } enum unprotected-preferred { value 3; description "Prefer unprotected SID"; } enum unprotected-only { value 4; description "Unprotected SID only"; } } description "Types for SID protection eligibility"; } typedef node-address-type { type inet:ipv6-address; description "Originator node address"; } typedef sid-algorithm-type { type uint8 { range "0..255"; } description "SID algorithm type"; } typedef color-type { type uint32 { range "1..4294967295"; } description "Policy color type"; } typedef name-type { type string { length "1..59"; } description "Policy name type"; } } Saleh, et al. Expires 24 November 2026 [Page 28] Internet-Draft YANG Data Model for SR Policy May 2026 Figure 3: ietf-sr-policy-types.yang 7.2. SR Policy This module references [RFC6780] and [RFC9256]. file "ietf-sr-policy@2026-05-23.yang" module ietf-sr-policy { namespace "urn:ietf:params:xml:ns:yang:ietf-sr-policy"; prefix "sr-policy"; import ietf-inet-types { prefix "inet"; } import ietf-interfaces { prefix if; } import ietf-routing { prefix "rt"; } import ietf-routing-types { prefix "rt-types"; } import ietf-yang-types { prefix "yang"; } import ietf-srv6-types { prefix "srv6-types"; } import ietf-sr-policy-types { prefix "sr-policy-types"; } import ietf-te-types { prefix "te-types"; } organization "IETF SPRING Working Group"; contact Saleh, et al. Expires 24 November 2026 [Page 29] Internet-Draft YANG Data Model for SR Policy May 2026 "WG Web: WG List: Editor: Kamran Raza Editor: Tarik Saleh Editor: Zhuang Shunwan Editor: Satoru Matsushima Editor: Vishnu Pavan Beeram "; description "This module contains a collection of YANG definitions for SR policy module. Copyright (c) 2024 IETF Trust and the persons identified as authors of the code. All rights reserved. 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 Revised 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. 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 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; // RFC Editor: replace XXXX with actual RFC number and remove // this note revision "2026-05-23" { description "Use the path metric type from te-types."; reference "RFC 9256"; } revision "2025-10-20" { description "Add the headend-address to the policy key to ensure global uniqueness across multiple headends, consistent with RFC 9256."; Saleh, et al. Expires 24 November 2026 [Page 30] Internet-Draft YANG Data Model for SR Policy May 2026 reference "RFC 9256"; } revision "2025-05-22" { description "Update the SR policy YANG model with more alignment with SR policy architecture"; reference "RFC XXXX: YANG Data Model for Segment-routing Policy"; // RFC Editor: replace XXXX with actual RFC number and remove // this note } revision "2024-11-22" { description "Fix SR policy YANG model"; reference "RFC XXXX: YANG Data Model for Segment-routing Policy"; // RFC Editor: replace XXXX with actual RFC number and remove // this note } revision "2024-03-04" { description "Alignment with SR policy architecture RFC9256"; reference "RFC XXXX: YANG Data Model for Segment-routing Policy"; // RFC Editor: replace XXXX with actual RFC number and remove // this note } revision "2022-03-28" { description "Alignment with SR policy architecture"; reference "draft-ietf-spring-sr-policy-yang"; } revision "2019-11-04" { description "Changes in keys for policy and its candidate paths"; reference "draft-raza-spring-sr-policy-yang"; } revision "2019-07-08" { description "Dynamic TE candidate-path support"; Saleh, et al. Expires 24 November 2026 [Page 31] Internet-Draft YANG Data Model for SR Policy May 2026 reference "draft-raza-spring-sr-policy-yang"; } revision "2018-07-01" { description "Initial version"; reference "draft-raza-spring-sr-policy-yang"; } //TBD: To be moved to srv6-base model when the model is ready grouping srv6-sid-info { description "Define an SRv6 SID"; leaf value { type srv6-types:srv6-sid; description "SRv6 SID value"; } leaf sid-behavior { type identityref { base srv6-types:srv6-endpoint-type; } description "SRv6 BSID behavior"; } container sid-structure { description "SRv6 BSID structure"; uses srv6-types:srv6-sid-structure-grouping; } } grouping srv6-bsid-type-b-config { description "SRv6 BSID Type-B config grouping"; leaf sid-behavior { type identityref { base srv6-types:srv6-endpoint-type; } description "SRv6 BSID behavior"; } container sid-structure { description "SRv6 BSID structure"; uses srv6-types:srv6-sid-structure-grouping; } } Saleh, et al. Expires 24 November 2026 [Page 32] Internet-Draft YANG Data Model for SR Policy May 2026 grouping segment_config { description "Segment properties grouping"; leaf index { type uint32; description "Segment index"; } leaf type { type identityref { base sr-policy-types:segment-type; } mandatory true; description "Segment type"; } container sr-mpls { description "SR-MPLS specific types"; container Type-A { description "Segment declared by MPLS label"; leaf value { type rt-types:mpls-label; description "MPLS label value"; } } container Type-C { description "Segment declared by IPv4 Prefix with optional SR Algorithm for SR-MPLS"; leaf ipv4-address { type inet:ipv4-address; description "Segment IPv4 address"; } leaf algorithm { type uint8; description "Prefix SID algorithm identifier"; } } container Type-D { description "Segment declared by IPv6 Global Prefix with optional SR Algorithm for SR-MPLS"; leaf ipv6-address { type inet:ipv6-address; description "Segment IPv6 address"; } Saleh, et al. Expires 24 November 2026 [Page 33] Internet-Draft YANG Data Model for SR Policy May 2026 leaf algorithm { type uint8; description "Prefix SID algorithm identifier"; } } container Type-E { description "Segment declared by IPv4 Prefix with Local Interface ID - SR-MPLS"; leaf ipv4-address { type inet:ipv4-address; description "Node IPv4 address"; } leaf interface-identifier { type uint32; description "local interface identifier"; } } container Type-F { description "Segment declared by IPv4 Addresses for link endpoints as Local, Remote pair - SR-MPLS"; leaf local-ipv4-address { type inet:ipv4-address; description "Segment local IPv4 adjacency address"; } leaf remote-ipv4-address { type inet:ipv4-address; description "Segment remote IPv4 adjacency address"; } } container Type-G { description "Segment declared by IPv6 Prefix and Interface ID for link endpoints as Local, Remote pair for SR-MPLS"; leaf local-ipv6-address { type inet:ipv6-address; description "Local link IPv6 address"; } leaf local-interface-identifier { type uint32; description "Local interface identifier"; } leaf remote-ipv6-address { type inet:ipv6-address; Saleh, et al. Expires 24 November 2026 [Page 34] Internet-Draft YANG Data Model for SR Policy May 2026 description "Remote link IPv6 address"; } leaf remote-interface-identifier { type uint32; description "Remote interface identifier"; } } container Type-H { description "Segment declared by IPv6 Addresses for link endpoints as Local, Remote pair for SR-MPLS"; leaf local-ipv6-address { type inet:ipv6-address; description "Segment local IPv6 adjacency address"; } leaf remote-ipv6-address { type inet:ipv6-address; description "Segment remote IPv6 adjacency address"; } } } // sr-mpls container srv6 { description "SRv6 specific types"; container Type-B { description "Segment declared by SRv6 SID value"; leaf value { type srv6-types:srv6-sid; description "SRv6 SID value"; } uses srv6-bsid-type-b-config; } container Type-I { description "Segment declared by IPv6 Global Prefix with optional SR Algorithm for SRv6"; leaf ipv6-address { type inet:ipv6-address; description "Segment IPv6 prefix"; } leaf algorithm { type uint8; description "Prefix SID algorithm identifier"; Saleh, et al. Expires 24 November 2026 [Page 35] Internet-Draft YANG Data Model for SR Policy May 2026 } } container Type-J { description "Segment declared by IPv6 Prefix and Interface ID for link endpoints as Local, Remote pair for SRv6"; leaf local-ipv6-address { type inet:ipv6-address; description "Local link IPv6 address"; } leaf local-interface-identifier { type uint32; description "Local interface identifier"; } leaf remote-ipv6-address { type inet:ipv6-address; description "Remote link IPv6 address"; } leaf remote-interface-identifier { type uint32; description "Remote interface identifier"; } } container Type-K { description "Segment declared by IPv6 Addresses for link endpoints as Local, Remote pair for SRv6"; leaf local-ipv6-address { type inet:ipv6-address; description "Segment local IPv6 adjacency address"; } leaf remote-ipv6-address { type inet:ipv6-address; description "Segment remote IPv6 adjacency address"; } } } // srv6 leaf validate { type boolean; default 'false'; description "Indicates whether the segment should be validated. The default applies to all segments other than the first segment. For the first segment, validation is always done."; } } Saleh, et al. Expires 24 November 2026 [Page 36] Internet-Draft YANG Data Model for SR Policy May 2026 grouping segment-properties { description "SR segment properties grouping"; uses segment_config; } grouping optimization-template-constraints { description "Constraints of optimization template"; container srlg { // the rule applies per link description "SRLG constraints on the computed dynamic path"; leaf-list exclude-any { type string; description "The link is excluded if it has any of these SRLG."; } } container affinity { // the rule applies per link description "Affinity constraints on the computed dynamic path"; leaf-list exclude-any { type string; description "The link is excluded if it has any of these affinities." ; } leaf-list include-any { type string; description "The link is accepted if it has any of these affinities"; } leaf-list include-all { type string; description "The link is accepted if it has all these affinities"; } } container ip-address { // the rule applies to e2e path and not per link description "IP address constraints on the computed dynamic path"; leaf-list exclude { Saleh, et al. Expires 24 November 2026 [Page 37] Internet-Draft YANG Data Model for SR Policy May 2026 type inet:ip-address; description "Must exclude the links that has any of these IP addresses."; } } container upper-bounds { description "Upper-bound constraints on the computed dynamic path"; container cumulative-metric { description "Path is invalid if its metric exceeds this value"; leaf metric-type { type identityref { base te-types:path-metric-type; } description "Metric type"; } leaf value { type uint32; description "Cumulative value"; } } leaf max-sids { type uint32; description "Path is invalid if it has more SIDs than this value"; } } container segment-rules { description "Constraints on the segments to be used in the path"; leaf sid-protection-eligibility { // currently applies to adj-sid segments only type sr-policy-types:sid-protection-eligibility-type; description "SID protection eligibility"; } } leaf max-sids { type uint32; description "Maximum number of SIDs in a segment-list"; } } Saleh, et al. Expires 24 November 2026 [Page 38] Internet-Draft YANG Data Model for SR Policy May 2026 grouping optimization-templates { description "Path optimization templates properties"; container optimization-templates { description "Path optimization templates"; list optimization-template { key "color"; description "Path optimization template"; leaf color { type uint32; description "Template identifier as a policy color"; } container candidate-paths { description "A list of candidate paths representing the optimization objectives and constraints"; list candidate-path { key "discriminator"; description "Candidate paths representing the optimization objectives and constraints"; leaf discriminator { type uint32; description "Candidate path distinguisher"; } uses cpath-optimization-objs; container constraints { description "Constraints of a path optimization template"; uses optimization-template-constraints; } } } } } } grouping attributes { description "Grouping containing attributes applicable to all SR policies"; container attributes { description "Attributes applicable to SR policies"; Saleh, et al. Expires 24 November 2026 [Page 39] Internet-Draft YANG Data Model for SR Policy May 2026 uses segment-lists; uses explicit-binding-sid-rules; } } grouping forwarding-counters { description "Grouping for counters"; container counters { config false; description "Counters containing stats related to forwarding"; leaf pkts { type yang:counter64; description "Number of packets forwarded"; } leaf octets { type yang:counter64; units "byte"; description "Number of bytes forwarded"; } } } grouping segment-lists { description "Segment lists grouping"; container segment-lists { description "Segment-lists properties"; list segment-list { key "name"; description "Segment-list properties"; leaf name { type string; description "Segment-list name"; } container segments { description "Segments for given segment list"; list segment { key "index"; description "Configure Segment/hop at the index"; uses segment-properties; } } } Saleh, et al. Expires 24 November 2026 [Page 40] Internet-Draft YANG Data Model for SR Policy May 2026 } } grouping binding-sid_config { description "Binding SID configuration properties grouping"; container mpls-sid { description "MPLS binding SIDs"; leaf value { type sr-policy-types:mpls-sid-value-type; description "MPLS binding SID value"; } } container srv6-sids { description "SRv6 binding SIDs"; list srv6-sid { key "index"; description "Configure an SRv6 binding-sid"; leaf index { type uint32; description "Binding SID index"; } leaf locator-name { type srv6-types:srv6-locator-name-type; description "Locator name used to allocate SRv6 binding SID"; } uses srv6-sid-info; } } } grouping binding-sid_state { description "Binding SID state properties grouping"; leaf alloc-mode { type sr-policy-types:binding-sid-alloc-mode; config false; description "Binding SID allocation mode"; } leaf allocated-sid { type sr-policy-types:sid-value-type; config false; description "Allocated SID value for the Binding SID"; } leaf oper-state { type sr-policy-types:binding-sid-oper-state; Saleh, et al. Expires 24 November 2026 [Page 41] Internet-Draft YANG Data Model for SR Policy May 2026 config false; description "Binding SID operational state"; } } grouping binding-sid-properties { description "Binding SID properties grouping"; container binding-sid { description "Binding Segment ID"; uses binding-sid_config; } } grouping path-forwarding_state { description "Policy Forwarding path information"; leaf path-id { type uint8; description "Primary path id"; } leaf next-hop-address { type inet:ip-address; description "Nexthop address"; } leaf next-hop-table-id { type uint32; description "Table ID for nexthop address"; } leaf interface { type if:interface-ref; description "Outgoing interface handle"; } leaf is-protected { type boolean; description "Is this path protected ?"; } leaf backup-path-id { type uint8; description "Backup path id"; } leaf is-pure-backup { type boolean; description "Is this path a pure backup ?"; } leaf weight { type uint32; description "Path's weight for W-ECMP balancing"; Saleh, et al. Expires 24 November 2026 [Page 42] Internet-Draft YANG Data Model for SR Policy May 2026 } container sid-list { description "Outgoing sid stack"; uses sid-list-grouping; } } grouping cpath-cmn-properties { description "Common properties of the candidate path"; leaf is-active { type boolean; config false; description "True if the candidate path is valid and used to forward traffic, False otherwise"; } leaf is-valid { type boolean; config false; description "True if at least one segment-list is valid, False otherwise"; } container computed-sid-list { config false; description "Computed SID list which could be different from outgoing SID list"; uses sid-list-grouping; } container forwarding-paths { config false; description "Forwarding state of paths"; list forwarding-path { key "path-id"; description "Forwarding path"; uses path-forwarding_state; uses forwarding-counters; } } } Saleh, et al. Expires 24 November 2026 [Page 43] Internet-Draft YANG Data Model for SR Policy May 2026 grouping explicit-path-properties { description "Explicit path properties of the candidate path"; container segment-lists { description "Path segment list(s) properties"; list segment-list { key "name-ref"; description "SR policy candidate path segment lists"; leaf name-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:attributes/" + "sr-policy:segment-lists/" + "sr-policy:segment-list/" + "sr-policy:name"; } description "Reference to segment-list name"; } leaf weight { type uint32; default 1; description "Segment-list weighted loadshare"; } leaf is-valid { type boolean; config false; description "True if the segment-list is valid, False otherwise"; } uses forwarding-counters; } } } grouping affinity-mapping { description "Affinity-map grouping"; container affinity-map { description "Mapping of affinity names to bit position"; list affinity { key "name"; unique "bit-position"; leaf name { Saleh, et al. Expires 24 November 2026 [Page 44] Internet-Draft YANG Data Model for SR Policy May 2026 type string; description "Name of the affinity"; } leaf bit-position { type uint16; description "The affinity entry in this list is mapped to the this bit-position in the affinity bitmap"; } description "Affinity"; } } } grouping srlg { description "SRLG grouping"; container srlgs { description "SRLG"; list srlg { key "name"; leaf name { type string; description "Name of the SRLG"; } leaf description { type string; description "Description of the SRLG"; } leaf value { type uint32; mandatory true; description "The associated value (for advertisements etc.) "; } description "SRLG"; } } } grouping cpath-optimization-objs { Saleh, et al. Expires 24 November 2026 [Page 45] Internet-Draft YANG Data Model for SR Policy May 2026 description "Candidate-path optimization objective grouping"; container optimization-objectives { description "Optimization objectives for the dynamic path computation"; container minimize-metric { description "The metric for which the path is optimized"; leaf metric-type { type identityref { base te-types:path-metric-type; } description "Metric type"; } container margin { description "The margin by which two paths with similar metric-type would be considered equal"; leaf type { type sr-policy-types:margin-type; description "Margin type"; } leaf value { type uint32; description "Margin value"; } leaf computed-value { type uint32; config false; description "Computed metric value"; } } } } } grouping cpath-constraints { description "Candidate-path constraints grouping"; container constraints { description "Constraints for the dynamic path computation"; container srlg { // the rule applies per link description "SRLG constraints on the computed dynamic path"; leaf-list exclude-any { type string; description Saleh, et al. Expires 24 November 2026 [Page 46] Internet-Draft YANG Data Model for SR Policy May 2026 "The link is excluded if it has any of these SRLG."; } leaf-list include-any { type string; description "The link is accepted if it has any of these SRLG"; } leaf-list include-all { type string; description "The link is accepted if it has all these SRLG"; } } container affinity { // the rule applies per link description "Affinity constraints on the computed dynamic path"; leaf-list exclude-any { type string; description "The link is excluded if it has any of these affinities." ; } leaf-list include-any { type string; description "The link is accepted if it has any of these affinities"; } leaf-list include-all { type string; description "The link is accepted if it has all these affinities"; } } container ip-address { // the rule applies to e2e path and not per link description "IP address constraints on the computed dynamic path"; leaf-list exclude { type inet:ip-address; description "Must exclude the links that has any of these IP addresses."; Saleh, et al. Expires 24 November 2026 [Page 47] Internet-Draft YANG Data Model for SR Policy May 2026 } leaf-list include-any { type inet:ip-address; description "Must include atleast 1 link (or possibly more) with any of these IP addresses."; } leaf-list include-all { type inet:ip-address; description "Must include all the links that have any of these IP addresses."; } } container upper-bounds { description "Upper-bound constraints on the computed dynamic path"; container cumulative-metric { description "Path is invalid if its metric exceeds this value"; leaf metric-type { type identityref { base te-types:path-metric-type; } description "Metric type"; } leaf value { type uint32; description "Cumulative value"; } } leaf max-sids { type uint32; description "Path is invalid if it has more SIDs than this value"; } } container segment-rules { description "Constraints on the segments to be used in the path"; leaf sid-algorithm { type sr-policy-types:sid-algorithm-type; description "The prefix-sid algorithm to be used in Saleh, et al. Expires 24 November 2026 [Page 48] Internet-Draft YANG Data Model for SR Policy May 2026 path calculation"; } leaf sid-protection-eligibility { // currently applies to adj-sid segments only type sr-policy-types:sid-protection-eligibility-type; description "SID protection eligibility"; } } container disjoint-path { description "Path disjointness constraints"; leaf disjointness-type { type te-types:te-path-disjointness; description "Type of disjointness computation used to find the path"; } leaf association-group-id { type uint16; mandatory true; description "Association group Id"; } leaf association-source { type inet:ip-address; mandatory true; description "Association source address"; } leaf association-extended-id { type yang:hex-string; description "Association extended identifier."; reference "RFC6780"; } } leaf max-sids { type uint32; description "Maximum number of SIDs in a segment-list"; } } } grouping dynamic-path-properties { Saleh, et al. Expires 24 November 2026 [Page 49] Internet-Draft YANG Data Model for SR Policy May 2026 description "Dynamic path properties of the candidate path"; container segment-list { description "Segment-list properties"; leaf segment-list-dataplane-type { type sr-policy-types:dataplane-type; mandatory true; description "The dataplane type for the segment-list"; } leaf is-valid { type boolean; config false; description "True if the segment-list is valid, False otherwise"; } uses forwarding-counters; } uses cpath-optimization-objs; uses cpath-constraints; } grouping composite-path-properties { description "Composite path properties of the candidate path"; container constituent-policies { description "Constituent SR policies"; list constituent-policy { key "color"; description "List of constituent SR policies"; leaf color { type sr-policy-types:color-type; description "Color associated with the constituent policy (the endpoint is same as the parent policy)"; } leaf weight { type uint32; default 1; description "Constituent policy weighted loadshare"; } } } } Saleh, et al. Expires 24 November 2026 [Page 50] Internet-Draft YANG Data Model for SR Policy May 2026 grouping mpls-label-stack { description "Grouping for MPLS label stack"; list labels { key "index"; description "Stack containing MPLS labels"; leaf index { type uint32; description "A unique ID of an MPLS label in labels list"; } leaf label { type rt-types:mpls-label; description "MPLS label value"; } } } grouping srv6-sid-stack { description "Grouping for SRv6 label stack"; list sids { key "index"; description "Stack containing SRv6 SIDs"; leaf index { type uint32; description "A unique ID of an SRv6 sid in sid list"; } leaf sid { type srv6-types:srv6-sid; description "SRv6 sid value"; } } } grouping sid-list-grouping { description "Grouping for SID list"; choice dataplane-type { description "Outgoing sids dataplane choice"; Saleh, et al. Expires 24 November 2026 [Page 51] Internet-Draft YANG Data Model for SR Policy May 2026 case mpls { uses mpls-label-stack; } case srv6 { uses srv6-sid-stack; } } } grouping candidate-path_state { description "Candidate path state properties grouping"; leaf is-best-candidate-path { type boolean; default 'false'; config false; description "True if the candidate path is the best candidate path, False otherwise"; } leaf non-selection-reason { type identityref { base sr-policy-types:candidate-path-not-selected-reason; } config false; description "Candidate path not selected reason"; } } grouping policy-properties_config { description "SR policy configuration grouping"; leaf name { type sr-policy-types:name-type; description "SR policy name"; } leaf headend { type inet:ip-address; description "The IP address identifying the SR Policy headend node. This addition ensures global uniqueness of the policy key across multiple headends"; reference "RFC 9256: Section 2.1 - Identification of an SR Policy."; } leaf color { type sr-policy-types:color-type; Saleh, et al. Expires 24 November 2026 [Page 52] Internet-Draft YANG Data Model for SR Policy May 2026 description "Color associated with the policy"; } leaf endpoint { type inet:ip-address; description "Policy end point IP address"; } leaf description { type string; description "Description of the policy"; } leaf admin-state { type sr-policy-types:policy-admin-state; default 'UP'; description "SR policy administrative state, true for enabled, false for disabled"; } leaf priority { type uint8; default 128; description "Priority considered when policy is recomputed due to topology changes"; } leaf profile-id { type uint32; description "A profile represents a set of configuration knobs specifying a policy or candidate-path attributes. The profile-ID feature allows usage of vendor/implementation specific functionality per policy without requiring explicit support by controller."; } container bandwidth { description "Bandwidth constraints"; leaf requested { type uint64; description "Requested bandwidth expressed in bytes per second"; } leaf reserved { type uint64; config false; description "Reserved bandwidth expressed in bytes per second"; } } Saleh, et al. Expires 24 November 2026 [Page 53] Internet-Draft YANG Data Model for SR Policy May 2026 } grouping policy-properties_state { description "SR policy property grouping"; leaf oper-state { type sr-policy-types:policy-oper-state; config false; description "SR policy operational state"; } leaf transition-count { type uint32; config false; description "Indicates number of up/down transitions"; } leaf up-time { type yang:date-and-time; config false; description "Policy up time in seconds"; } leaf down-time { type yang:date-and-time; config false; description "Policy down time in seconds"; } } grouping policy-properties { description "SR policy properties"; uses policy-properties_config; uses policy-properties_state; uses binding-sid-properties; uses forwarding-counters; } grouping candidate-path-type { description "Candidate path type grouping"; choice type { description "Type of candidate paths"; case explicit { description "Candidate path with explicitly defined set/s of segment-lists"; uses explicit-path-properties; } case dynamic { Saleh, et al. Expires 24 November 2026 [Page 54] Internet-Draft YANG Data Model for SR Policy May 2026 description "Candidate path with dynamic computed segment-lists"; uses dynamic-path-properties; } case composite { description "Candidate path that groups SR policies each with explicit and/or dynamic candidate path with potentially different optimization objectives and constraints"; uses composite-path-properties; } } } grouping candidate-paths { description "SR policy candidate path grouping"; container candidate-paths { description "SR policy candidate path(s) "; list candidate-path { key "protocol-origin originator-asn originator-node-address discriminator"; unique "preference"; description "SR policy Candidate path(s) list entry"; leaf protocol-origin { type identityref { base sr-policy-types:protocol-origin-type; } description "Instantiation mechanism used to create the candidate path"; } leaf originator-asn { type uint32; description "The autonomous system number (ASN) of the provisioning node. If 2-byte ASNs are in use, the low-order 16 bits MUST be used, and the high-order bits MUST be set to 0"; } leaf originator-node-address { type sr-policy-types:node-address-type; description "represented as a 128-bit value. IPv4 addresses MUST be encoded in the lowest 32 bits, and the high-order bits MUST be set to 0"; Saleh, et al. Expires 24 November 2026 [Page 55] Internet-Draft YANG Data Model for SR Policy May 2026 } leaf discriminator { type uint32; description "Candidate path distinguisher"; } leaf preference { type uint32 { range "1..65535"; } mandatory true; description "Candidate path preference"; } leaf name { type string; description "Candidate path name"; } leaf description { type string; description "Candidate path description"; } leaf drop-upon-invalid { type boolean; description "Enable traffic dropping when LSP is invalid"; } leaf admin-state { type boolean; description "Shutdown the candidate-path"; } container binding-sid { if-feature capability-candidate-path-binding-sid; description "Binding segment ID"; uses binding-sid_config; } uses candidate-path-type; uses candidate-path_state; uses cpath-cmn-properties; } } } grouping policies { description "SR policy grouping"; container policies { description "SR Policy container"; list policy { Saleh, et al. Expires 24 November 2026 [Page 56] Internet-Draft YANG Data Model for SR Policy May 2026 key "headend color endpoint"; unique "name"; description "List of SR Policies. Each SR Policy is uniquely identified by the tuple globally, as defined in RFC 9256. The headend identifies the ingress node that instantiates or owns this policy."; uses policy-properties; uses candidate-paths; } } } grouping explicit-binding-sid-rules { description "Grouping for explicit binding sid rules"; list explicit-binding-sid-rules { key "index"; description "Explicit binding sid rules applicable for all policies"; leaf index { type uint32; description "Explicit binding SID rules list index"; } leaf rule { type sr-policy-types:explicit-binding-sid-rule-type; mandatory true; description "Explicit binding sid rule"; } } } augment "/rt:routing" { description "This augments routing-instance configuration with segment-routing sr-policy."; container segment-routing { description "Main segment routing container"; container traffic-engineering { description "Traffic-engineering container"; uses optimization-templates; uses attributes; uses policies; } } Saleh, et al. Expires 24 November 2026 [Page 57] Internet-Draft YANG Data Model for SR Policy May 2026 } augment "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:binding-sid/" + "sr-policy:mpls-sid" { description "Augments binding-sid state with MPLS binding-sid"; uses binding-sid_state; } augment "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:binding-sid/" + "sr-policy:srv6-sids/" + "sr-policy:srv6-sid" { description "Augments binding-sid state with SRv6 binding-sid"; uses binding-sid_state; } /* Notifications */ notification sr-policy-oper-state-change-event { description "Notification event when the operational state of the SR policy changes"; leaf policy-name-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:name"; } description "Reference to sr-policy name"; } leaf policy-color-ref { type leafref { Saleh, et al. Expires 24 November 2026 [Page 58] Internet-Draft YANG Data Model for SR Policy May 2026 path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:color"; } description "Reference to sr-policy color"; } leaf policy-endpoint-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:endpoint"; } description "Reference to sr-policy endpoint"; } leaf policy-new-oper-state { type sr-policy-types:policy-oper-state; description "New operational state of the SR policy"; } leaf policy-down-reason { type identityref { base sr-policy-types:policy-down-reason; } description "Down reason if the SR policy's new operational state is down"; } } notification sr-policy-candidate-path-change-event { description "Notification event when candidate path changes for SR policy"; leaf policy-name-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" Saleh, et al. Expires 24 November 2026 [Page 59] Internet-Draft YANG Data Model for SR Policy May 2026 + "sr-policy:name"; } description "Reference to sr-policy name"; } leaf policy-color-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:color"; } description "Reference to sr-policy color"; } leaf policy-endpoint-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:endpoint"; } description "Reference to sr-policy endpoint"; } leaf existing-preference { type uint32; description "Existing candidate path preference"; } leaf new-preference { type uint32; description "New candidate path preference"; } } notification sr-policy-binding-sid-unavailable-event { description "Notification event when the binding sid of sr-policy is unavailable"; leaf policy-name-ref { type leafref { path "/rt:routing/" Saleh, et al. Expires 24 November 2026 [Page 60] Internet-Draft YANG Data Model for SR Policy May 2026 + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:name"; } description "Reference to sr-policy name"; } leaf policy-color-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:color"; } description "Reference to sr-policy color"; } leaf policy-endpoint-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:endpoint"; } description "Reference to sr-policy endpoint"; } choice dataplane-type { description "Binding SID dataplane choice"; case mpls { leaf policy-mpls-binding-sid-value-ref { if-feature capability-candidate-path-binding-sid; type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:binding-sid/" + "sr-policy:mpls-sid/" + "sr-policy:value"; Saleh, et al. Expires 24 November 2026 [Page 61] Internet-Draft YANG Data Model for SR Policy May 2026 } description "Reference to sr-policy MPLS binding SID value"; } } case srv6 { leaf policy-srv6-binding-sid-value-ref { if-feature capability-candidate-path-binding-sid; type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:binding-sid/" + "sr-policy:srv6-sids/" + "sr-policy:srv6-sid/" + "sr-policy:value"; } description "Reference to sr-policy SRv6 binding SID value"; } } } leaf reason { type identityref { base sr-policy-types:binding-sid-unavailable-reason; } description "Reason why the binding sid is unavailable"; } } notification sr-policy-candidate-path-binding-sid-mismatch-event { description "Notification event when binding sid of requested candidate path is different from the binding sid of the existing candidate path"; leaf policy-color-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:color"; } description "Reference to sr-policy color"; Saleh, et al. Expires 24 November 2026 [Page 62] Internet-Draft YANG Data Model for SR Policy May 2026 } leaf policy-endpoint-ref { type leafref { path "/rt:routing/" + "sr-policy:segment-routing/" + "sr-policy:traffic-engineering/" + "sr-policy:policies/" + "sr-policy:policy/" + "sr-policy:endpoint"; } description "Reference to sr-policy endpoint"; } leaf existing-candidate-path-protocol-origin-ref { 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"; } description "Reference to existing candidate path protocol origin"; } leaf existing-candidate-path-preference-ref { 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:preference"; } description "Reference to existing candidate path preference"; } choice dataplane-type { description "Binding SID dataplane choice"; case mpls { leaf existing-candidate-path-mpls-binding-sid-value-ref { Saleh, et al. Expires 24 November 2026 [Page 63] Internet-Draft YANG Data Model for SR Policy May 2026 if-feature capability-candidate-path-binding-sid; 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:binding-sid/" + "sr-policy:mpls-sid/" + "sr-policy:value"; } description "Reference to existing candidate path MPLS binding SID " + "value"; } } case srv6 { leaf existing-candidate-path-srv6-binding-sid-value-ref { if-feature capability-candidate-path-binding-sid; 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:binding-sid/" + "sr-policy:srv6-sids/" + "sr-policy:srv6-sid/" + "sr-policy:value"; } description "Reference to existing candidate path SRv6 binding SID " + "value"; } } } leaf conflicting-candidate-path-protocol-origin { type uint8; description "Conflicting candidate path protocol origin"; } leaf conflicting-candidate-path-preference { type uint32; Saleh, et al. Expires 24 November 2026 [Page 64] Internet-Draft YANG Data Model for SR Policy May 2026 description "Conflicting candidate path preference"; } leaf conflicting-candidate-path-binding-sid-dataplane { type sr-policy-types:dataplane-type; description "Conflicting candidate path binding sid dataplane type"; } leaf conflicting-candidate-path-binding-sid-value { type sr-policy-types:sid-value-type; description "Conflicting candidate path binding sid value"; } } /* Features */ feature capability-candidate-path-binding-sid { description "This feature enables the capability of specifying binding-sid for a candidate path."; } } Figure 4: ietf-sr-policy.yang 8. Security Considerations The YANG modules defined in this document are designed to be accessed via YANG-based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of the protocol operations and content. The "ietf-sr-policy-types" module defines reusable identities, typedefs, and groupings. By itself, it does not define configuration or state data nodes, RPCs, actions, or notifications. As such, it does not by itself create additional security concerns beyond those that apply to modules that reuse these definitions. The "ietf-sr-policy" module defines writable configuration data under /rt:routing/sr-policy:segment-routing/traffic-engineering. These writable data nodes are likely to be reasonably sensitive or Saleh, et al. Expires 24 November 2026 [Page 65] Internet-Draft YANG Data Model for SR Policy May 2026 vulnerable in some network environments. Write or delete access to these nodes without proper protection can change the path that traffic follows, redirect traffic, black-hole traffic, or disrupt service. The following writable subtrees have particular sensitivities: * /rt:routing/sr-policy:segment-routing/traffic-engineering/ optimization-templates * /rt:routing/sr-policy:segment-routing/traffic-engineering/ attributes/segment-lists * /rt:routing/sr-policy:segment-routing/traffic-engineering/ attributes/explicit-binding-sid-rules * /rt:routing/sr-policy:segment-routing/traffic-engineering/ policies Some of the readable data nodes and notifications in the "ietf-sr- policy" module may also be considered sensitive or vulnerable in some network environments because they expose policy identifiers, endpoints, candidate-path selection state, segment list contents, binding SID values, and failure reasons. In particular, read access to the operational state under /rt:routing/sr-policy:segment-routing/ traffic-engineering/policies and to the notifications sr-policy-oper- state-change-event, sr-policy-candidate-path-change-event, sr-policy- binding-sid-unavailable-event, and sr-policy-candidate-path-binding- sid-mismatch-event should be controlled. The YANG modules in this document do not define any RPC or action operations. 9. IANA Considerations This document requests the registration of the following URIs in the IETF "XML registry" [RFC3688]: +==================================================+==========+===+ | URI |Registrant|XML| +==================================================+==========+===+ | urn:ietf:params:xml:ns:yang:ietf-sr-policy-types |The IESG |N/A| +--------------------------------------------------+----------+---+ +--------------------------------------------------+----------+---+ | urn:ietf:params:xml:ns:yang:ietf-sr-policy |The IESG |N/A| +--------------------------------------------------+----------+---+ Table 3 Saleh, et al. Expires 24 November 2026 [Page 66] Internet-Draft YANG Data Model for SR Policy May 2026 This document requests the registration of the following YANG modules in the "YANG Module Names" registry [RFC7950]: +========+===================================+=========+===========+ |Name | Namespace | Prefix | Reference | +========+===================================+=========+===========+ |ietf-sr-| urn:ietf:params:xml:ns:yang:ietf- | sr- | This | |policy- | sr-policy-types | policy- | document | |types | | types | | +--------+-----------------------------------+---------+-----------+ +--------+-----------------------------------+---------+-----------+ |ietf-sr-| urn:ietf:params:xml:ns:yang:ietf- | sr- | This | |policy | sr-policy | policy | document | +--------+-----------------------------------+---------+-----------+ Table 4 10. Acknowledgments The authors of this document/YANG model would like to acknowledge the contributions/reviews by Johnson Thomas, Clarence Filsfils, Siva Sivabalan, Tarek Saad, Kris Michielsen, Dhanendra Jain, Ketan Talaulikar, Bhupendra Yadav, and Bruno Decraene. 11. References 11.1. 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, . [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, . [RFC6780] Berger, L., Le Faucheur, F., and A. Narayanan, "RSVP ASSOCIATION Object Extensions", RFC 6780, DOI 10.17487/RFC6780, October 2012, . Saleh, et al. Expires 24 November 2026 [Page 67] Internet-Draft YANG Data Model for SR Policy May 2026 [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8294] Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger, "Common YANG Data Types for the Routing Area", RFC 8294, DOI 10.17487/RFC8294, 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, . [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, . [RFC8343] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, 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, . [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, . Saleh, et al. Expires 24 November 2026 [Page 68] Internet-Draft YANG Data Model for SR Policy May 2026 [RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", RFC 8407, DOI 10.17487/RFC8407, October 2018, . [RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", RFC 9256, DOI 10.17487/RFC9256, July 2022, . 11.2. Informative References [I-D.ietf-idr-segment-routing-te-policy] Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., and D. Jain, "Advertising Segment Routing Policies in BGP", Work in Progress, Internet-Draft, draft-ietf-idr-segment- routing-te-policy-26, 23 October 2023, . [I-D.ietf-spring-srv6-yang] Raza, S. K., Rajamanickam, J., Matsushima, S., Yu, P., and X. Liu, "YANG Data Model for SRv6 Base and Static", Work in Progress, Internet-Draft, draft-ietf-spring-srv6-yang- 05, 7 July 2025, . [I-D.ietf-teas-rfc8776-update] Busi, I., Guo, A., Liu, X., Saad, T., and I. Bryskin, "Common YANG Data Types for Traffic Engineering", Work in Progress, Internet-Draft, draft-ietf-teas-rfc8776-update- 23, 20 May 2026, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . Appendix A. Contributors Robert Sawaya Cisco Systems Email: rsawaya@cisco.com Daniel Voyer Individual Email: danvoyerwork@gmail.com Saleh, et al. Expires 24 November 2026 [Page 69] Internet-Draft YANG Data Model for SR Policy May 2026 Muhammad Durrani Oracle Corporation Muahmmad.durrani@oracle.com Authors' Addresses Tarik Saleh (editor) Cisco Systems Email: tasaleh@cisco.com Kamran Raza Cisco Systems Email: skraza@cisco.com Zhuang Shunwan Huawei Technologies Email: zhuangshunwan@huawei.com Satoru Matsushima SoftBank Email: satoru.matsushima@g.softbank.co.jp Vishnu Pavan Beeram Juniper Networks Email: vbeeram@juniper.net Saleh, et al. Expires 24 November 2026 [Page 70]