LSR Working Group S. Litkowski Internet-Draft Cisco Systems Intended status: Standards Track Y. Qu Expires: 2 January 2025 Futurewei Technologies P. Sarkar Individual I. Chen The MITRE Corporation J. Tantsura Nvidia 1 July 2024 A YANG Data Model for IS-IS Segment Routing for the MPLS Data Plane draft-ietf-isis-sr-yang-22 Abstract This document defines a YANG data module that can be used to configure and manage IS-IS Segment Routing for MPLS data plane. 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 2 January 2025. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components Litkowski, et al. Expires 2 January 2025 [Page 1] Internet-Draft IS-IS SR MPLS YANG July 2024 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. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 2 2. Design of the IS-IS MPLS Segment Routing Module . . . . . . . 3 2.1. Segment Routing Activation . . . . . . . . . . . . . . . 3 2.2. Advertising Mapping Server Policy . . . . . . . . . . . . 3 2.3. IP Fast Reroute . . . . . . . . . . . . . . . . . . . . . 3 3. IS-IS MPLS Segment Routing Module Tree . . . . . . . . . . . 3 4. IS-IS MPLS Segment Routing YANG Module . . . . . . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 26 6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 27 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 27 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 9.1. Normative References . . . . . . . . . . . . . . . . . . 28 9.2. Informative References . . . . . . . . . . . . . . . . . 30 Appendix A. A Configuration Example . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 1. Overview This document defines a YANG data model [RFC7950] that can be used to configure and manage IS-IS Segment Routing [RFC8667] for MPLS data plane and it is an augmentation to the IS-IS YANG data model [RFC9130]. The YANG module in this document conforms to the Network Management Datastore Architecture (NMDA) [RFC8342]. 1.1. 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. 1.2. Tree Diagrams This document uses the graphical representation of data models defined in [RFC8340]. Litkowski, et al. Expires 2 January 2025 [Page 2] Internet-Draft IS-IS SR MPLS YANG July 2024 2. Design of the IS-IS MPLS Segment Routing Module This document defines a YANG model for IS-IS Segment Routing for the MPLS data plane. It is an augmentation of the IS-IS base model. The IS-IS SR MPLS YANG module requires support for the base segment routing module [RFC9020], which defines the global segment routing configuration independent of any specific routing protocol configuration, and support of IS-IS base model [RFC9130] which defines basic IS-IS configuration and state. 2.1. Segment Routing Activation Activation of IS-IS SR MPLS is done by setting the "enable" leaf to true. This triggers advertisement of SR MPLS extensions based on the configuration parameters that have been setup using the base segment routing module. 2.2. Advertising Mapping Server Policy The base segment routing module defines mapping server policies. By default, IS-IS will not advertise or process any mapping server entry. The IS-IS SR MPLS module allows the advertisement of one or multiple mapping server policies through the "bindings/advertise/ policies" leaf-list. The "bindings/receive" leaf controls the reception and process of mapping server entries. 2.3. IP Fast Reroute IS-IS SR MPLS model augments the fast-reroute container under interface. It brings the ability to activate TI-LFA (topology independent LFA) and also enhances remote LFA to use segment-routing tunneling instead of LDP. 3. IS-IS MPLS Segment Routing Module Tree The figure below describes the overall structure of the isis-sr-mpls YANG module: module: ietf-isis-sr-mpls augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis: +--rw segment-routing | +--rw enabled? boolean | +--rw bindings {mapping-server}? | +--rw advertise | | +--rw policies* -> /rt:routing/sr:segment-routing | | /sr-mpls:sr-mpls/bindings Litkowski, et al. Expires 2 January 2025 [Page 3] Internet-Draft IS-IS SR MPLS YANG July 2024 | | /mapping-server/policy/name | +--rw receive? boolean +--rw protocol-srgb {sr-mpls:protocol-srgb}? +--rw srgb* [lower-bound upper-bound] +--rw lower-bound uint32 +--rw upper-bound uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis /isis:interfaces/isis:interface: +--rw segment-routing +--rw adjacency-sid +--rw adj-sids* [value] | +--rw value-type? enumeration | +--rw value uint32 | +--rw protected? boolean | +--rw weight? uint8 | +--rw neighbor-system-id isis:system-id +--rw advertise-adj-group-sid* [group-id] | +--rw group-id uint32 +--rw advertise-protection? enumeration augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:interfaces /isis:interface/isis:fast-reroute/isis:lfa: +--rw ti-lfa {ti-lfa}? +--rw enabled? boolean +--rw selection-tie-breakers +--rw node-protection! | +--rw priority? uint8 +--rw srlg-disjoint! +--rw priority? uint8 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:interfaces /isis:interface/isis:fast-reroute/isis:lfa/isis:level-1: +--rw ti-lfa {ti-lfa}? +--rw enabled? boolean augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:interfaces /isis:interface/isis:fast-reroute/isis:lfa/isis:level-2: +--rw ti-lfa {ti-lfa}? +--rw enabled? boolean augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:interfaces /isis:interface/isis:fast-reroute/isis:lfa/isis:remote-lfa: +--rw use-segment-routing-path? boolean {remote-lfa-sr}? augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:interfaces /isis:interface/isis:adjacencies/isis:adjacency: +--ro adjacency-sid* [value] Litkowski, et al. Expires 2 January 2025 [Page 4] Internet-Draft IS-IS SR MPLS YANG July 2024 +--ro value uint32 +--ro address-family? iana-rt-types:address-family +--ro weight? uint8 +--ro protection-requested? boolean augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:router-capabilities: +--ro sr-capability | +--ro sr-capability | | +--ro sr-capability-flags* identityref | +--ro global-blocks | +--ro global-block* [] | +--ro range-size? uint32 | +--ro sid-sub-tlv | +--ro length? uint8 | +--ro sid? uint32 +--ro sr-algorithms | +--ro sr-algorithm* identityref +--ro local-blocks | +--ro local-block* [] | +--ro range-size? rt-types:uint24 | +--ro sid-sub-tlv | +--ro length? uint8 | +--ro sid? uint32 +--ro srms-preference +--ro preference? uint8 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:extended-is-neighbor /isis:neighbor: +--ro sid-list* [sid] +--ro adj-sid-flags | +--ro flags* identityref +--ro weight? uint8 +--ro neighbor-id? isis:system-id +--ro sid uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:mt-is-neighbor/isis:neighbor: +--ro sid-list* [sid] +--ro adj-sid-flags | +--ro flags* identityref +--ro weight? uint8 +--ro neighbor-id? isis:system-id +--ro sid uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:extended-ipv4-reachability Litkowski, et al. Expires 2 January 2025 [Page 5] Internet-Draft IS-IS SR MPLS YANG July 2024 /isis:prefixes: +--ro prefix-sid-sub-tlvs +--ro prefix-sid-sub-tlv* [sid] +--ro prefix-sid-flags | +--ro flags* identityref +--ro algorithm? identityref +--ro sid uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:mt-extended-ipv4-reachability /isis:prefixes: +--ro prefix-sid-sub-tlvs +--ro prefix-sid-sub-tlv* [sid] +--ro prefix-sid-flags | +--ro flags* identityref +--ro algorithm? identityref +--ro sid uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:ipv6-reachability/isis:prefixes: +--ro prefix-sid-sub-tlvs +--ro prefix-sid-sub-tlv* [sid] +--ro prefix-sid-flags | +--ro flags* identityref +--ro algorithm? identityref +--ro sid uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp/isis:mt-ipv6-reachability /isis:prefixes: +--ro prefix-sid-sub-tlvs +--ro prefix-sid-sub-tlv* [sid] +--ro prefix-sid-flags | +--ro flags* identityref +--ro algorithm? identityref +--ro sid uint32 augment /rt:routing/rt:control-plane-protocols /rt:control-plane-protocol/isis:isis/isis:database /isis:levels/isis:lsp: +--ro sid-binding-tlvs | +--ro sid-binding-tlv* [prefix] | +--ro prefix inet:ip-prefix | +--ro range? uint16 | +--ro sid-binding-flags | | +--ro flags* identityref | +--ro prefix-sid-sub-tlvs* [] | | +--ro prefix-sid-sub-tlvs | | +--ro prefix-sid-sub-tlv* [sid] Litkowski, et al. Expires 2 January 2025 [Page 6] Internet-Draft IS-IS SR MPLS YANG July 2024 | | +--ro prefix-sid-flags | | | +--ro flags* identityref | | +--ro algorithm? identityref | | +--ro sid uint32 | +--ro sid-sub-tlvs* [] | | +--ro sid-sub-tlv | | +--ro length? uint8 | | +--ro sid? uint32 | +--ro unknown-tlvs | +--ro unknown-tlv* [] | +--ro type? uint16 | +--ro length? uint16 | +--ro value? yang:hex-string +--ro mt-sid-binding-tlvs +--ro mt-sid-binding-tlv* [prefix mt-id] +--ro prefix inet:ip-prefix +--ro range? uint16 +--ro sid-binding-flags | +--ro flags* identityref +--ro prefix-sid-sub-tlvs* [] | +--ro prefix-sid-sub-tlvs | +--ro prefix-sid-sub-tlv* [sid] | +--ro prefix-sid-flags | | +--ro flags* identityref | +--ro algorithm? identityref | +--ro sid uint32 +--ro sid-sub-tlvs* [] | +--ro sid-sub-tlv | +--ro length? uint8 | +--ro sid? uint32 +--ro unknown-tlvs | +--ro unknown-tlv* [] | +--ro type? uint16 | +--ro length? uint16 | +--ro value? yang:hex-string +--ro mt-id uint16 4. IS-IS MPLS Segment Routing YANG Module [RFC6991], [RFC8102], [RFC8294], [RFC8349], [RFC8667], [RFC9020], [RFC9130], and [I-D.ietf-rtgwg-segment-routing-ti-lfa] are referenced in the YANG model. Litkowski, et al. Expires 2 January 2025 [Page 7] Internet-Draft IS-IS SR MPLS YANG July 2024 file "ietf-isis-sr-mpls@2024-01-22.yang" module ietf-isis-sr-mpls { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-isis-sr-mpls"; prefix isis-sr-mpls; import ietf-routing { prefix rt; reference "RFC 8349 - A YANG Data Model for Routing Management (NMDA Version)"; } import ietf-inet-types { prefix inet; reference "RFC 6991 - Common YANG Data Types"; } import ietf-segment-routing-common { prefix sr-cmn; reference "RFC 9020 - YANG Data Model for Segment Routing"; } import ietf-segment-routing-mpls { prefix sr-mpls; reference "RFC 9020 - YANG Data Model for Segment Routing"; } import ietf-isis { prefix isis; reference "RFC 9130 - YANG Data Model for IS-IS Protocol"; } import iana-routing-types { prefix iana-rt-types; reference "RFC 8294 - Common YANG Data Types for the Routing Area"; } import ietf-routing-types { prefix rt-types; reference "RFC 8294 - Common YANG Data Types for the Routing Area"; } organization "IETF LSR - Link State Routing Working Group"; contact "WG Web: WG List: Litkowski, et al. Expires 2 January 2025 [Page 8] Internet-Draft IS-IS SR MPLS YANG July 2024 Author: Stephane Litkowski Author: Yingzhen Qu Author: Acee Lindem Author: Pushpasis Sarkar Author: Ing-Wher Chen Author: Jeff Tantsura "; description "The YANG module defines the generic configuration and operational state for Segment Routing ISIS extensions for the MPLS data plane, which is common across all of the vendor implementations. This YANG model conforms to the Network Management Datastore Architecture (NMDA) as described in RFC 8342. 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 (https://www.rfc-editor.org/info/rfcXXXX); 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. This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; reference "RFC XXXX"; revision 2024-01-22 { Litkowski, et al. Expires 2 January 2025 [Page 9] Internet-Draft IS-IS SR MPLS YANG July 2024 description "Initial revision."; reference "RFC XXXX: A YANG Data Model for IS-IS Segment Routing for the MPLS Data Plane"; } /* Identities */ identity sr-capability { description "Base identity for ISIS SR-Capabilities sub-TLV flags"; reference "RFC 8667 - IS-IS Extensions for Segment Routing"; } identity mpls-ipv4 { base sr-capability; description "If set, then the router is capable of processing SR MPLS encapsulated IPv4 packets on all interfaces."; } identity mpls-ipv6 { base sr-capability; description "If set, then the router is capable of processing SR MPLS encapsulated IPv6 packets on all interfaces."; } identity prefix-sid-flag { description "Base identity for prefix SID sub-TLV flags."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.1"; } identity r-flag { base prefix-sid-flag; description "Re-advertisement Flag."; } identity n-flag { base prefix-sid-flag; description Litkowski, et al. Expires 2 January 2025 [Page 10] Internet-Draft IS-IS SR MPLS YANG July 2024 "Node-SID Flag."; } identity p-flag { base prefix-sid-flag; description "No-PHP (No Penultimate Hop-Popping) Flag."; } identity e-flag { base prefix-sid-flag; description "Explicit NULL Flag."; } identity v-flag { base prefix-sid-flag; description "Value Flag."; } identity l-flag { base prefix-sid-flag; description "Local Flag."; } identity adj-sid-flag { description "Base identity for Adj-SID sub-TLV flags."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.2"; } identity f-flag { base adj-sid-flag; description "Address-Family flag."; } identity b-flag { base adj-sid-flag; description "Backup flag."; } identity vi-flag { base adj-sid-flag; Litkowski, et al. Expires 2 January 2025 [Page 11] Internet-Draft IS-IS SR MPLS YANG July 2024 description "Value/Index flag."; } identity lo-flag { base adj-sid-flag; description "Local flag."; } identity s-flag { base adj-sid-flag; description "Group flag."; } identity pe-flag { base adj-sid-flag; description "Persistent flag."; } identity sid-binding-flag { description "Base identity for sid binding tlv flags."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.4"; } identity af-flag { base sid-binding-flag; description "Address-Family flag."; } identity m-flag { base sid-binding-flag; description "Mirror Context flag."; } identity sf-flag { base sid-binding-flag; description "S flag. If set, the binding label TLV should be flooded across the entire routing domain."; } Litkowski, et al. Expires 2 January 2025 [Page 12] Internet-Draft IS-IS SR MPLS YANG July 2024 identity d-flag { base sid-binding-flag; description "Leaking flag."; } identity a-flag { base sid-binding-flag; description "Attached flag."; } /* Features */ feature remote-lfa-sr { description "Enhance rLFA to use SR path."; reference "RFC 8102: Remote-LFA Node Protection and Manageability"; } feature ti-lfa { description "Topology-Independent Loop-Free Alternate (TI-LFA) computation using segment routing."; reference "draft-ietf-rtgwg-segment-routing-ti-lfa - Topology-Independent Fast Reroute using Segment Routing"; } /* Groupings */ grouping sid-sub-tlv { description "SID/Label sub-TLV grouping."; container sid-sub-tlv { description "Used to advertise the SID/Label associated with a prefix or adjacency."; leaf length { type uint8; description "Length of the SID value. YANG model specification is necessary since it dictates the semantics of the SID."; } leaf sid { type uint32; Litkowski, et al. Expires 2 January 2025 [Page 13] Internet-Draft IS-IS SR MPLS YANG July 2024 description "Segment Identifier (SID) - A 20 bit label or 32 bit SID. If the length is set to 3, then the 20 rightmost bits represent an MPLS label. If the length is set to 4, then the value is a 32-bit index."; } } } grouping sr-capability { description "SR capability grouping."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 3"; container sr-capability { description "Segment Routing capability."; container sr-capability { leaf-list sr-capability-flags { type identityref { base sr-capability; } description "SR Capability sub-TLV flags."; } description "SR Capability Flags."; } container global-blocks { description "Segment Routing Global Blocks."; list global-block { description "Segment Routing Global Block."; leaf range-size { type uint32; description "The SID range."; } uses sid-sub-tlv; } } } } grouping sr-algorithm { description "SR algorithm grouping."; Litkowski, et al. Expires 2 January 2025 [Page 14] Internet-Draft IS-IS SR MPLS YANG July 2024 container sr-algorithms { description "All SR algorithms."; leaf-list sr-algorithm { type identityref { base sr-cmn:prefix-sid-algorithm; } description "The Segment Routing (SR) algorithms that the router is currently using."; } } } grouping srlb { description "SR Local Block grouping."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 3.3"; container local-blocks { description "List of SRLBs."; list local-block { description "Segment Routing Local Block."; leaf range-size { type rt-types:uint24; description "The SID range."; } uses sid-sub-tlv; } } } grouping srms-preference { description "The SRMS preference TLV is used to advertise a preference associated with the node that acts as an SR Mapping Server."; container srms-preference { description "SRMS Preference TLV."; leaf preference { type uint8; description "SRMS preference TLV, value from 0 to 255 with 255 being the most preferred."; Litkowski, et al. Expires 2 January 2025 [Page 15] Internet-Draft IS-IS SR MPLS YANG July 2024 } } } grouping adjacency-state { description "This grouping extends adjacency state."; list adjacency-sid { key "value"; config false; leaf value { type uint32; description "Value of the Adj-SID."; } leaf address-family { type iana-rt-types:address-family; description "Address-family associated with the segment ID"; } leaf weight { type uint8; description "Weight associated with the adjacency SID."; } leaf protection-requested { type boolean; description "Describe if the adjacency SID must be protected."; } description "List of adjacency Segment IDs."; } } grouping prefix-sid-sub-tlv { description "This grouping defines segment routing prefix segment identifier (prefix-sid) sub-tlv."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.1"; container prefix-sid-sub-tlvs { description "PrefixSID sub-tlvs."; list prefix-sid-sub-tlv { Litkowski, et al. Expires 2 January 2025 [Page 16] Internet-Draft IS-IS SR MPLS YANG July 2024 key "sid"; container prefix-sid-flags { leaf-list flags { type identityref { base prefix-sid-flag; } description "Prefix SID sub-TLV flags."; } description "Describes flags associated with the segment ID."; } leaf algorithm { type identityref { base sr-cmn:prefix-sid-algorithm; } description "Algorithm to be used for path computation."; } leaf sid { type uint32; description "Value of the prefix-SID."; } description "List of prefix-sid sub-tlvs."; } } } grouping adjacency-segment-id { description "This grouping defines segment routing extensions for adjacencies."; list sid-list { key "sid"; container adj-sid-flags { leaf-list flags { type identityref { base adj-sid-flag; } description "Adj-SID sub-TLV flags list."; } description "Adj-SID sub-TLV flags."; } Litkowski, et al. Expires 2 January 2025 [Page 17] Internet-Draft IS-IS SR MPLS YANG July 2024 leaf weight { type uint8; description "The value represents the weight of the Adj-SID for the purpose of load balancing."; } leaf neighbor-id { type isis:system-id; description "Describes the system ID of the neighbor associated with the SID value. This is only used on LAN adjacencies."; } leaf sid { type uint32; description "Value of the Adj-SID."; } description "List of segments."; } } grouping sid-binding-tlv { leaf prefix { type inet:ip-prefix; description "The prefix represents the Forwarding Equivalence Class at the tail end of the advertised path."; } leaf range { type uint16; description "Provides the ability to specify a range of addresses and their associated prefix-sids."; } container sid-binding-flags { leaf-list flags { type identityref { base sid-binding-flag; } description "SID Binding TLV flags."; } description "Binding TLV flags."; } list prefix-sid-sub-tlvs { Litkowski, et al. Expires 2 January 2025 [Page 18] Internet-Draft IS-IS SR MPLS YANG July 2024 uses prefix-sid-sub-tlv; description "List of prefix-sid sub-tlvs."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.4.4"; } list sid-sub-tlvs { uses sid-sub-tlv; description "List of prefix-sid sub-tlvs."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.4.5"; } uses isis:unknown-tlvs; description "SID/Label binding TLV, type 149."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.4"; } /* Configuration */ augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis" { when "derived-from-or-self(../rt:type, 'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing for the MPLS data plane."; uses sr-mpls:sr-control-plane; container protocol-srgb { if-feature "sr-mpls:protocol-srgb"; uses sr-cmn:srgb; description "Per-protocol Segment Routing Global Block (SRGB)."; reference "RFC 8402 - Segment Routing Architecture, Section 2"; } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" Litkowski, et al. Expires 2 January 2025 [Page 19] Internet-Draft IS-IS SR MPLS YANG July 2024 + "/isis:isis/isis:interfaces/isis:interface" { when "derived-from-or-self(../../../rt:type, 'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses sr-mpls:igp-interface { augment "segment-routing/adjacency-sid/adj-sids" { when "../../../isis:interface-type = 'broadcast'" { description "This augments broadcast interface."; } description "This augments LAN interface adj-sid with system-id."; leaf neighbor-system-id { type isis:system-id; mandatory true; description "Neighbor system ID."; } } } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:interfaces/isis:interface" + "/isis:fast-reroute/isis:lfa" { when "derived-from-or-self(../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS interface IP FRR with TILFA."; container ti-lfa { if-feature "ti-lfa"; leaf enabled { type boolean; default "false"; description "Enables TI-LFA computation."; } container selection-tie-breakers { container node-protection { presence "Presence of container enables the node Litkowski, et al. Expires 2 January 2025 [Page 20] Internet-Draft IS-IS SR MPLS YANG July 2024 protection tie-breaker"; leaf priority { type uint8; default "128"; description "Priority for node protection tie-breaker with a lower priority being more preferred."; } description "Enable node protection as a TI-LFA path selection tie-breaker. A path providing node protection will be selected over one that doesn't provide node protection."; } container srlg-disjoint { presence "Presence of container enables the SRLG disjoint tie-breaker"; leaf priority { type uint8; default "128"; description "Priority for SRLG disjoint tie-breaker with a lower priority being more preferred."; } description "Enable SRLG (Shared Resource Link Group) disjoint as a TI-LFA path selection tie-breaker. A path providing node a disjoint path for SRLG links from the primary path will be selected over one that doesn't provide an SRLG disjoint path."; } description "Configure path selection tie-breakers and their respective priorities for the TI-LFA computation."; } description "Topology Independent Loop Free Alternate (TI-LFA) support."; } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:interfaces/isis:interface" + "/isis:fast-reroute/isis:lfa/isis:level-1" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description Litkowski, et al. Expires 2 January 2025 [Page 21] Internet-Draft IS-IS SR MPLS YANG July 2024 "This augments ISIS routing protocol when used"; } description "This augments ISIS interface level-1 IP FRR with TILFA."; container ti-lfa { if-feature "ti-lfa"; leaf enabled { type boolean; default "false"; description "Enables TI-LFA computation."; } description "TI-LFA configuration."; } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:interfaces/isis:interface" + "/isis:fast-reroute/isis:lfa/isis:level-2" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS IP interface level-2 FRR with TILFA."; container ti-lfa { if-feature "ti-lfa"; leaf enabled { type boolean; default "false"; description "Enables TI-LFA computation."; } description "TI-LFA configuration."; } } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:interfaces/isis:interface" + "/isis:fast-reroute/isis:lfa/isis:remote-lfa" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description Litkowski, et al. Expires 2 January 2025 [Page 22] Internet-Draft IS-IS SR MPLS YANG July 2024 "This augments ISIS routing protocol when used"; } description "This augments ISIS remoteLFA config with use of segment-routing path."; leaf use-segment-routing-path { if-feature "remote-lfa-sr"; type boolean; default "false"; description "Force remote LFA to use segment routing path instead of LDP path. The value of this leaf is in effect only when remote-lfa is enabled."; } } /* Operational states */ augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:interfaces/isis:interface" + "/isis:adjacencies/isis:adjacency" { when "derived-from-or-self(../../../../../rt:type, 'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol configuration with segment routing."; uses adjacency-state; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:router-capabilities" { when "derived-from-or-self(../../../../../rt:type, 'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB router capability."; uses sr-capability; uses sr-algorithm; uses srlb; uses srms-preference; } Litkowski, et al. Expires 2 January 2025 [Page 23] Internet-Draft IS-IS SR MPLS YANG July 2024 augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:extended-is-neighbor/isis:neighbor" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB neighbor."; uses adjacency-segment-id; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:mt-is-neighbor/isis:neighbor" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB neighbor."; uses adjacency-segment-id; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:extended-ipv4-reachability/isis:prefixes" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-sid-sub-tlv; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:mt-extended-ipv4-reachability/isis:prefixes" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { Litkowski, et al. Expires 2 January 2025 [Page 24] Internet-Draft IS-IS SR MPLS YANG July 2024 description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-sid-sub-tlv; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:ipv6-reachability/isis:prefixes" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-sid-sub-tlv; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" + "/isis:mt-ipv6-reachability/isis:prefixes" { when "derived-from-or-self(../../../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB prefix."; uses prefix-sid-sub-tlv; } augment "/rt:routing/" + "rt:control-plane-protocols/rt:control-plane-protocol" + "/isis:isis/isis:database/isis:levels/isis:lsp" { when "derived-from-or-self(../../../../rt:type," + "'isis:isis')" { description "This augments ISIS routing protocol when used"; } description "This augments ISIS protocol LSDB."; container sid-binding-tlvs { list sid-binding-tlv { Litkowski, et al. Expires 2 January 2025 [Page 25] Internet-Draft IS-IS SR MPLS YANG July 2024 key "prefix"; uses sid-binding-tlv; description "Sid/label binding TLV, type 149."; } description "List of sid/label binding TLVs."; } container mt-sid-binding-tlvs { list mt-sid-binding-tlv { key "prefix mt-id"; uses sid-binding-tlv; leaf mt-id { type uint16; description "A 12-bit field containing the non-zero ID of the topology."; } description "Multi-Topology SID/Label binding TLV, type 150."; reference "RFC 8667 - IS-IS Extensions for Segment Routing, Section 2.5"; } description "List of multi-topology sid/label binding TLVs."; } } } 5. Security Considerations The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446]. The NETCONF Access Control Model (NACM) [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. Litkowski, et al. Expires 2 January 2025 [Page 26] Internet-Draft IS-IS SR MPLS YANG July 2024 There are a number of data nodes defined in this YANG module that 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., edit-config) 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: /isis:isis/segment-routing /isis:isis/protocol-srgb /isis:isis/isis:interfaces/isis:interface/segment-routing /isis:isis/isis:interfaces/isis:interface/isis:fast-reroute/ti-lfa Some of the readable data nodes in the modules 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. /isis:router-capabilities/sr-capability /isis:router-capabilities/sr-algorithms /isis:router-capabilities/local-blocks /isis:router-capabilities/srms-preference /isis:router-capabilities/node-msd-tlv And the augmentations to the ISIS link state database. Unauthorized access to any data node of these subtrees can disclose the operational state information of IS-IS protocol on this device. 6. Contributors Authors would like to thank Derek Yeung, Acee Lindem, Yi Yang for their major contributions to the draft. Also thank Reshad Rahman, and Tom Petch for their thorough reviews and helpful comments. 7. Acknowledgements MITRE has approved this document for Public Release, Distribution Unlimited, with Public Release Case Number 19-3033. Litkowski, et al. Expires 2 January 2025 [Page 27] Internet-Draft IS-IS SR MPLS YANG July 2024 8. IANA Considerations The IANA is requested to assign one new URI from the IETF XML registry ([RFC3688]). Authors are suggesting the following URI: URI: urn:ietf:params:xml:ns:yang:ietf-isis-sr-mpls Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace This document also requests one new YANG module name in the YANG Module Names registry ([RFC6020]) with the following suggestion : name: ietf-isis-sr-mpls namespace: urn:ietf:params:xml:ns:yang:ietf-isis-sr-mpls prefix: isis-sr-mpls reference: RFC XXXX 9. References 9.1. Normative References [I-D.ietf-rtgwg-segment-routing-ti-lfa] Bashandy, A., Litkowski, S., Filsfils, C., Francois, P., Decraene, B., and D. Voyer, "Topology Independent Fast Reroute using Segment Routing", Work in Progress, Internet-Draft, draft-ietf-rtgwg-segment-routing-ti-lfa- 16, 29 June 2024, . [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, . [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, . Litkowski, et al. Expires 2 January 2025 [Page 28] Internet-Draft IS-IS SR MPLS YANG July 2024 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [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, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8102] Sarkar, P., Ed., Hegde, S., Bowers, C., Gredler, H., and S. Litkowski, "Remote-LFA Node Protection and Manageability", RFC 8102, DOI 10.17487/RFC8102, March 2017, . [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, . [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, . Litkowski, et al. Expires 2 January 2025 [Page 29] Internet-Draft IS-IS SR MPLS YANG July 2024 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C., Bashandy, A., Gredler, H., and B. Decraene, "IS-IS Extensions for Segment Routing", RFC 8667, DOI 10.17487/RFC8667, December 2019, . [RFC9020] Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J. Tantsura, "YANG Data Model for Segment Routing", RFC 9020, DOI 10.17487/RFC9020, May 2021, . [RFC9130] Litkowski, S., Ed., Yeung, D., Lindem, A., Zhang, J., and L. Lhotka, "YANG Data Model for the IS-IS Protocol", RFC 9130, DOI 10.17487/RFC9130, October 2022, . 9.2. Informative References [RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu, "Handling Long Lines in Content of Internet-Drafts and RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020, . Appendix A. A Configuration Example The following is an XML example using the ISIS SR MPLS YANG module defined in this document. Note: '\' line wrapping per [RFC8792]. Litkowski, et al. Expires 2 January 2025 [Page 30] Internet-Draft IS-IS SR MPLS YANG July 2024 1.1.1.1 \ isis:isis isis 1111.2222.3333 38888 true 4000 5000 The following is the same example using JSON format. Litkowski, et al. Expires 2 January 2025 [Page 31] Internet-Draft IS-IS SR MPLS YANG July 2024 { "routing": { "router-id": "1.1.1.1", "control-plane-protocols": { "control-plane-protocol": { "type": "isis:isis", "name": "isis", "isis": { "system-id": "1111.2222.3333", "interfaces": { "interface": { "name": "", "segment-routing": { "adjacency-sid": { "adj-sids": { "value": 38888 } } } } }, "segment-routing": { "enabled": true }, "protocol-srgb": { "srgb": { "lower-bound": 4000, "upper-bound": 5000 } } } } } } } Authors' Addresses Stephane Litkowski Cisco Systems Email: slitkows.ietf@gmail.com Yingzhen Qu Futurewei Technologies Email: yingzhen.ietf@gmail.com Litkowski, et al. Expires 2 January 2025 [Page 32] Internet-Draft IS-IS SR MPLS YANG July 2024 Pushpasis Sarkar Individual Email: pushpasis.ietf@gmail.com Ing-Wher Chen The MITRE Corporation Email: ingwherchen@mitre.org Jeff Tantsura Nvidia Email: jefftant.ietf@gmail.com Litkowski, et al. Expires 2 January 2025 [Page 33]