Network Working Group X. Liu Internet-Draft Volta Networks Intended status: Standards Track I. Bryskin Expires: August 26, 2021 Individual V. Beeram T. Saad Juniper Networks H. Shah Ciena S. Litkowski Cisco February 22, 2021 YANG Data Model for SR and SR TE Topologies on MPLS Data Plane draft-ietf-teas-yang-sr-te-topo-09 Abstract This document defines a YANG data model for Segment Routing (SR) topology and Segment Routing (SR) traffic engineering (TE) topology, using 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 August 26, 2021. Copyright Notice Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of Liu, et al. Expires August 26, 2021 [Page 1] Internet-Draft YANG SR MPLS Topology February 2021 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 3 1.3. Prefixes in Data Node Names . . . . . . . . . . . . . . . 3 2. Modeling Considerations . . . . . . . . . . . . . . . . . . . 3 2.1. Segment Routing (SR) MPLS Topology . . . . . . . . . . . 3 2.2. Segment Routing (SR) MPLS TE Topology . . . . . . . . . . 4 2.3. Relations to ietf-segment-routing . . . . . . . . . . . . 7 2.4. Topology Type Modeling . . . . . . . . . . . . . . . . . 7 2.5. Topology Attributes . . . . . . . . . . . . . . . . . . . 7 2.6. Node Attributes . . . . . . . . . . . . . . . . . . . . . 7 2.7. Link Attributes . . . . . . . . . . . . . . . . . . . . . 8 3. Model Structure . . . . . . . . . . . . . . . . . . . . . . . 9 4. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 11 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 7.1. Normative References . . . . . . . . . . . . . . . . . . 22 7.2. Informative References . . . . . . . . . . . . . . . . . 24 Appendix A. Companion YANG Model for Non-NMDA Compliant Implementations . . . . . . . . . . . . . . . . . . 26 A.1. SR MPLS Topology State Module . . . . . . . . . . . . . . 26 Appendix B. Data Tree Example . . . . . . . . . . . . . . . . . 29 Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 36 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 1. Introduction This document defines a YANG [RFC7950] data model for describing the presentations of Segment Routing (SR) topology and Segment Routing (SR) traffic engineering (TE) topology. The version of the model limits the transport type to an MPLS dataplane. 1.1. Terminology 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 Liu, et al. Expires August 26, 2021 [Page 2] Internet-Draft YANG SR MPLS Topology February 2021 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. The following terms are defined in [RFC7950] and are not redefined here: o augment o data model o data node 1.2. Tree Diagrams Tree diagrams used in this document follow the notation defined in [RFC8340]. 1.3. Prefixes in Data Node Names In this document, names of data nodes, actions, and other data model objects are often used without a prefix, as long as it is clear from the context in which YANG module each name is defined. Otherwise, names are prefixed using the standard prefix associated with the corresponding YANG module, as shown in Table 1. +--------+-----------------------------+---------------------------+ | Prefix | YANG module | Reference | +--------+-----------------------------+---------------------------+ | nw | ietf-network | [RFC8345] | | nt | ietf-network-topology | [RFC8345] | | l3t | ietf-l3-unicast-topology | [RFC8346] | | sr-cmn | ietf-segment-routing-common | [I-D.ietf-spring-sr-yang] | +--------+-----------------------------+---------------------------+ Table 1: Prefixes and Corresponding YANG Modules 2. Modeling Considerations 2.1. Segment Routing (SR) MPLS Topology The Layer 3 network topology model is discussed in [RFC8346]. The Segment Routing (SR) MPLS topology model proposed in this document augments and uses the ietf-l3-unicast-topology module defined in [RFC8346]. SR MPLS related attributes are covered in the ietf-sr- mpls-topology module. Liu, et al. Expires August 26, 2021 [Page 3] Internet-Draft YANG SR MPLS Topology February 2021 +------------------------------+ | Layer 3 Network Topology | | ietf-l3-unicast-topology | +---------------^--------------+ | | | | +------------^-----------+ | SR MPLS Topology | | ietf-sr-mpls-topology | +------------------------+ Figure 1: SR MPLS topology augmentation 2.2. Segment Routing (SR) MPLS TE Topology A Segment Routing (SR) MPLS TE topology is an instance of SR MPLS topology with TE enabled. In order to instantiate an SR MPLS TE topology, the ietf-sr-mpls-topology module defined in this document can be used together with the ietf-te-topology module defined in [RFC8795] and the ietf-te-topology-packet module defined in [I-D.ietf-teas-yang-l3-te-topo]. All these modules directly or indirectly augment the ietf-network-topology module defind in [RFC8345], as shown in Figure 2. Liu, et al. Expires August 26, 2021 [Page 4] Internet-Draft YANG SR MPLS Topology February 2021 +---------------------------+ | Network Topology | | ietf-network-topology | +-^-----------------------^-+ / \ / \ / \ / \ +-------------^-------------+ +-------------^-------------+ | Layer 3 Unicast Topology | | TE Topology | | ietf-l3-unicast-topology | | ietf-te-topology | +-------------^-------------+ +-------------^-------------+ | | | | | | | | +-------------^-------------+ +-------------^-------------+ | SR MPLS Topology | | TE Packet Topology | | ietf-sr-mpls-topology | | ietf-te-topology-packet | +---------------------------+ +---------------------------+ Figure 2: SR TE topology instance inheritance relations Figure 3 shows the data structure of an SR TE topology instance. Because of the augmentation relationships shown in Figure 2, a data instance of an SR MPLS TE topology contains the capabilities from all these modules, so that the data includes the attributes from ietf- network-topology, ietf-l3-unicast-topology, ietf-sr-mpls-topology, ietf-te-topology, and ietf-te-topology-packet. Liu, et al. Expires August 26, 2021 [Page 5] Internet-Draft YANG SR MPLS Topology February 2021 +--------------------------------------------------------+ | ietf-network-topology: | | network-id (key) | | network-types: { | | l3-unicast-topology: { | | sr-mpls{} | | } | | te-topology: { | | packet{} | | } | | } | | | +-----------------------------+--------------------------+ | ietf-l3-unicast-topology: | ietf-te-topology: | | | | +-----------------------------+--------------------------+ | ietf-sr-mpls-topology: | ietf-te-topology-packet: | | | | +-----------------------------+--------------------------+ Figure 3: SR TE topology instance data structure Each type of topologies is indicated by "network-types" defined in [RFC8345]. For the five types of topologies above, the data representations are: Base network topology: /nd:networks/nd:network/nd:network-types Layer 3 Unicast Topology: /nd:networks/nd:network/nd:network-types/l3-unicast-topology SR MPLS Topology: /nd:networks/nd:network/nd:network-types/l3-unicast-topology/sr-mpls TE Topology: /nd:networks/nd:network/nd:network-types/te-topology TE Packet Topology: /nd:networks/nd:network/nd:network-types/te-topology/packet Liu, et al. Expires August 26, 2021 [Page 6] Internet-Draft YANG SR MPLS Topology February 2021 2.3. Relations to ietf-segment-routing [I-D.ietf-spring-sr-yang] defines ietf-segment-routing that is a model intended to be used on network elements to configure or operate segment routing; ietf-sr-mpls-topology defined in this document is intended to be used on a controller for the network-wide operations such as path computation. SR MPLS topology model shares many modeling constructs defined in ietf-segment-routing. The module ietf-sr-mpls-topology uses the types and groupings defined in ietf-segment-routing. 2.4. Topology Type Modeling A new topology type is defined in this document, to indicate a topology that is a Segment Routing (SR) topology on an MPLS dataplane. augment /nw:networks/nw:network/nw:network-types /l3t:l3-unicast-topology: +--rw sr-mpls! 2.5. Topology Attributes The Segment Routing attributes with topology-wide impacts are modeled by augmenting the container "l3-topology-attributes" in the L3 topology model. SRGB (Segment Routing Global Block) is covered in this augmentation. A SR domain is mapped to a topology in this model. augment /nw:networks/nw:network/l3t:l3-topology-attributes: +--rw sr-mpls +--rw srgb* [lower-bound upper-bound] +--rw lower-bound uint32 +--rw upper-bound uint32 2.6. Node Attributes The Segment Routing attributes within the node scope are modeled by augmenting the sub tree /nw:networks/nw:network/nw:node/ in the L3 topology model. The SR attributes that have node-scope impact are modeled by augmenting the container "l3-node-attributes" in the L3 topology model, including the SR capabilities, SRGB (Segment Routing Global Block), and SRLB (Segment Routing Local Block) specified on this mode. This model also provides the information about how these SR attributes are learned: Liu, et al. Expires August 26, 2021 [Page 7] Internet-Draft YANG SR MPLS Topology February 2021 augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes: +--rw sr-mpls! +--rw srgb* [lower-bound upper-bound] | +--rw lower-bound uint32 | +--rw upper-bound uint32 +--rw srlb* [lower-bound upper-bound] | +--rw lower-bound uint32 | +--rw upper-bound uint32 +--ro node-capabilities | +--ro entropy-readable-label-depth? uint8 +--rw msd? uint8 {msd}? +--ro information-source? enumeration +--ro information-source-state +--ro credibility-preference? uint16 The SR attributes that are related to a IGP-Prefix segment are modeled by augmenting the list entry "prefix" in the L3 topology model: augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes /l3t:prefix: +--rw sr-mpls! +--rw value-type? enumeration +--rw start-sid uint32 +--rw range? uint32 +--rw algorithm? identityref +--rw last-hop-behavior? enumeration | {sid-last-hop-behavior}? +--rw is-local? boolean +--rw is-node? boolean +--ro is-readvertisment? boolean 2.7. Link Attributes A link in the topology model connects the termination point on the source node to the termination point on the destination node. When such a link is instantiated, the bindings between the nodes and the corresponding Adj-SIDs are formed, and the resulting FIB entries are installed. A link in the topology model is mapped to an SR Adjacency Segment, formed by a pair of interfaces on two respective adjacent nodes. The SR Adjacency Segment attributes are modeled by augmenting the link attributes of the L3 topology model. The modeling structure is as follows: Liu, et al. Expires August 26, 2021 [Page 8] Internet-Draft YANG SR MPLS Topology February 2021 augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes: +--rw sr-mpls! +--rw value-type? enumeration +--rw sid uint32 +--rw advertise-protection? enumeration +--rw is-local? boolean +--rw msd? uint8 {msd}? +--rw address-family? enumeration +--rw is-backup? boolean +--rw is-part-of-set? boolean +--rw is-persistent? boolean +--rw is-on-lan? boolean +--ro information-source? enumeration +--ro information-source-state +--ro credibility-preference? uint16 The usage of the leaf "advertise-protection" is described in [I-D.ietf-spring-sr-yang]. IGPs [RFC8665] [RFC8666] [RFC8667] and BGP-LS [RFC7752] [I-D.ietf-idr-bgp-ls-segment-routing-ext] can be supported by the model, the leaf "information-source" is used to indicate where the information is from. The bundling capability of the Adjacency Segemnt is achieved by re- using the existing modeling construct (i.e. "bundle-stack-level") under /nw:networks/nw:network/nt:link/tet:te [RFC8795] 3. Model Structure The model tree structure of the Segment Routing (SR) topology module is as shown below: module: ietf-sr-mpls-topology augment /nw:networks/nw:network/nw:network-types /l3t:l3-unicast-topology: +--rw sr-mpls! augment /nw:networks/nw:network/l3t:l3-topology-attributes: +--rw sr-mpls +--rw srgb* [lower-bound upper-bound] +--rw lower-bound uint32 +--rw upper-bound uint32 augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes: +--rw sr-mpls! +--rw srgb* [lower-bound upper-bound] | +--rw lower-bound uint32 Liu, et al. Expires August 26, 2021 [Page 9] Internet-Draft YANG SR MPLS Topology February 2021 | +--rw upper-bound uint32 +--rw srlb* [lower-bound upper-bound] | +--rw lower-bound uint32 | +--rw upper-bound uint32 +--rw msds {msd}? | +--rw node-msd* [msd-type] | +--rw msd-type identityref | +--rw msd-value? uint8 +--ro information-source? enumeration +--ro information-source-instance? string +--ro information-source-state +--ro credibility-preference? uint16 augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes /l3t:prefix: +--rw sr-mpls! +--rw sids +--rw sid* [algorithm] +--rw value-type? enumeration +--rw start-sid uint32 +--rw range? uint32 +--rw algorithm identityref +--rw last-hop-behavior? enumeration | {sid-last-hop-behavior}? +--rw is-local? boolean +--rw is-node? boolean +--ro is-readvertisment? boolean augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes: +--rw sr-mpls! +--rw msds {msd}? | +--rw link-msd* [msd-type] | +--rw msd-type identityref | +--rw msd-value? uint8 +--rw sids | +--rw sid* [value-type sid] | +--rw value-type enumeration | +--rw sid uint32 | +--rw address-family? enumeration | +--rw is-eligible-for-protection? boolean | +--rw is-local? boolean | +--rw is-part-of-set? boolean | +--rw is-persistent? boolean | +--rw is-on-lan? boolean | +--rw weight? uint8 +--ro information-source? enumeration +--ro information-source-instance? string +--ro information-source-state +--ro credibility-preference? uint16 Liu, et al. Expires August 26, 2021 [Page 10] Internet-Draft YANG SR MPLS Topology February 2021 4. YANG Module This module references [RFC7752], [RFC8345], [RFC8346], [RFC8476], [RFC8491], [RFC8665], [RFC8666], [RFC8667], [RFC8814], [I-D.ietf-spring-sr-yang], and [I-D.ietf-idr-bgp-ls-segment-routing-ext]. file "ietf-sr-mpls-topology@2021-02-05.yang" module ietf-sr-mpls-topology { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology"; prefix "srmt"; import ietf-network { prefix "nw"; reference "RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-network-topology { prefix "nt"; reference "RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-l3-unicast-topology { prefix "l3t"; reference "RFC 8346: A YANG Data Model for Layer 3 Topologies"; } import ietf-segment-routing-common { prefix "sr-cmn"; reference "I-D.ietf-spring-sr-yang: YANG Data Model for Segment Routing"; } organization "IETF Traffic Engineering Architecture and Signaling (TEAS) Working Group"; contact "WG Web: WG List: Editor: Xufeng Liu Editor: Igor Bryskin Editor: Vishnu Pavan Beeram Liu, et al. Expires August 26, 2021 [Page 11] Internet-Draft YANG SR MPLS Topology February 2021 Editor: Tarek Saad Editor: Himanshu Shah Editor: Stephane Litkowski "; description "YANG data model for representing and manipulating Segment Routing Topologies on MPLS Data Plane. Copyright (c) 2021 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2021-02-05 { description "Initial revision"; reference "RFC XXXX: YANG Data Model for SR and SR TE Topologies"; } identity msd-base-type { description "Base identity for MSD Type"; } identity base-mpls-msd { base msd-base-type; description "Base MPLS Imposition MSD."; reference "RFC 8491: Singling MSD using IS-IS."; } identity erld-msd { base msd-base-type; description Liu, et al. Expires August 26, 2021 [Page 12] Internet-Draft YANG SR MPLS Topology February 2021 "ERLD-MSD is defined to advertise the ERLD."; reference "RFC 8662: Entropy Label for Source Packet Routing in Networking (SPRING) Tunnels"; } feature msd { description "Support of signaling MSD (Maximum SID Depth) in IGP."; reference "RFC 8476: Signaling Maximum SID Depth (MSD) Using OSPF. RFC 8491: Signaling Maximum SID Depth (MSD) Using IS-IS. RFC 8814: Signaling Maximum SID Depth (MSD) Using the Border Gateway Protocol - Link State."; } grouping sr-mpls-topology-type { description "Identifies the SR-MPLS topology type. This type of network topologies use Segment Routing (SR) technology over the MPLS data plane"; container sr-mpls { presence "Indicates SR-MPLS topology"; description "Its presence identifies the SR topology type."; } } augment "/nw:networks/nw:network/nw:network-types/" + "l3t:l3-unicast-topology" { description "Defines the SR topology type."; uses sr-mpls-topology-type; } augment "/nw:networks/nw:network/l3t:l3-topology-attributes" { when "../nw:network-types/l3t:l3-unicast-topology/srmt:sr-mpls" { description "Augment only for SR topology."; } description "Augment topology configuration"; uses sr-mpls-topology-attributes; } augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes" { when "../../nw:network-types/l3t:l3-unicast-topology/" + "srmt:sr-mpls" { description "Augment only for SR topology."; } Liu, et al. Expires August 26, 2021 [Page 13] Internet-Draft YANG SR MPLS Topology February 2021 description "Augment node configuration."; uses sr-node-attributes; } augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes" + "/l3t:prefix" { when "../../../nw:network-types/l3t:l3-unicast-topology/" + "srmt:sr-mpls" { description "Augment only for SR topology."; } description "Augment node prefix."; uses sr-node-prefix-attributes; } augment "/nw:networks/nw:network/nt:link/l3t:l3-link-attributes" { when "../../nw:network-types/l3t:l3-unicast-topology/" + "srmt:sr-mpls" { description "Augment only for SR topology."; } description "Augment link configuration"; uses sr-link-attributes; } grouping sr-mpls-topology-attributes { description "SR topology scope attributes."; container sr-mpls { description "Containing SR attributes."; uses sr-cmn:srgb; } // sr } // sr-mpls-topology-attributes grouping information-source-attributes { description "The attributes identifying source that has provided the related information, and the source credibility."; leaf information-source { type enumeration { enum "unknown" { description "The source is unknown."; } enum "locally-configured" { description "Configured entity."; } enum "ospfv2" { description "OSPFv2."; reference "RFC 8665: OSPF Extensions for Segment Routing."; Liu, et al. Expires August 26, 2021 [Page 14] Internet-Draft YANG SR MPLS Topology February 2021 } enum "ospfv3" { description "OSPFv3."; reference "RFC 8666: OSPFv3 Extensions for Segment Routing."; } enum "isis" { description "ISIS."; reference "RFC 8667: IS-IS Extensions for Segment Routing."; } enum "bgp-ls" { description "BGP-LS."; reference "RFC 7752: North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP. I-D.ietf-idr-bgp-ls-segment-routing-ext: BGP Link-State extensions for Segment Routing."; } enum "system-processed" { description "System processed entity."; } enum "other" { description "Other source."; } } config false; description "Indicates the type of the information source."; } leaf information-source-instance { type string; config false; description "The name indicating the instance of the information source."; } container information-source-state { config false; description "The container contains state attributes related to the information source."; leaf credibility-preference { type uint16; description "The preference value to calculate the traffic engineering database credibility value used for tie-break selection between different Liu, et al. Expires August 26, 2021 [Page 15] Internet-Draft YANG SR MPLS Topology February 2021 information-source values. Higher value is more preferable."; } } } // information-source-attributes grouping sr-node-attributes { description "SR node scope attributes."; container sr-mpls { presence "Presence indicates SR is enabled."; description "Containing SR attributes."; uses sr-cmn:srgb; uses sr-cmn:srlb; container msds { if-feature "msd"; description "MSDs on the node."; list node-msd { key "msd-type"; leaf msd-type { type identityref { base msd-base-type; } description "MSD-Types"; } leaf msd-value { type uint8; description "MSD value, in the range of 0-255. Node MSD is the lowest MSD supported by the node."; } description "List of node MSDs"; } } // Operational state data uses information-source-attributes; } // sr } // sr-node-attributes grouping sr-node-prefix-attributes { description "Containing SR attributes for a prefix."; container sr-mpls { presence "Presence indicates SR is enabled."; description "Containing SR attributes for a prefix."; Liu, et al. Expires August 26, 2021 [Page 16] Internet-Draft YANG SR MPLS Topology February 2021 container sids { description "Containing Prefix SIDs assigned to this prefix."; list sid { key "algorithm"; description "A list of SIDs with their properties."; uses sr-cmn:prefix-sid-attributes; uses sr-cmn:last-hop-behavior; leaf is-local { type boolean; default false; description "'true' if the SID is local."; } leaf is-node { type boolean; default false; description "'true' if the Prefix-SID refers to the router identified by the prefix. Typically, the leaf 'is-node' (N-Flag) is set on Prefix-SIDs attached to a router loopback address."; } leaf is-readvertisment { type boolean; config false; description "'true' if the prefix to which this Prefix-SID is attached, has been propagated by the router from another topology by redistribution."; reference "RFC 8667: IS-IS Extensions for Segment Routing. Sec 2.1."; } } } } // sr } // sr-node-prefix-attributes grouping sr-link-attributes { description "SR link scope attributes"; container sr-mpls { presence "Presence indicates SR is enabled."; description "Containing SR attributes."; container msds { Liu, et al. Expires August 26, 2021 [Page 17] Internet-Draft YANG SR MPLS Topology February 2021 if-feature "msd"; description "MSDs on the link."; list link-msd { key "msd-type"; leaf msd-type { type identityref { base msd-base-type; } description "MSD-Types"; } leaf msd-value { type uint8; description "MSD value, in the range of 0-255."; } description "List of link MSDs"; } } container sids { description "Containing Adjacentcy SIDs assigned to this link."; list sid { key "value-type sid"; description "A list of SIDs with their properties."; uses sr-cmn:sid-value-type; leaf sid { type uint32; mandatory true; description "Adjacency SID, which can be either IGP-Adjacency SID or BGP PeerAdj SID, depending on the context."; } leaf address-family { type enumeration { enum "ipv4" { description "The Adj-SID refers to an adjacency with outgoing IPv4 encapsulation."; } enum "ipv6" { description "The Adj-SID refers to an adjacency with outgoing IPv6 encapsulation."; } Liu, et al. Expires August 26, 2021 [Page 18] Internet-Draft YANG SR MPLS Topology February 2021 } default "ipv4"; description "This leaf defines the F-Flag (Address-Family flag) of the SID."; } leaf is-eligible-for-protection { type boolean; default false; description "'true' if the SID is is eligible for protection."; reference "RFC 8402: Segment Routing Architecture. Sec. 3.4."; } leaf is-local { type boolean; default false; description "'true' if the SID is local."; } leaf is-part-of-set { type boolean; default false; description "'true' if the SID is part of a set."; } leaf is-persistent { type boolean; default true; description "'true' if the SID is persistently allocated."; } leaf is-on-lan { type boolean; default false; description "'true' if on a lan."; } leaf weight { type uint8; description "The value represents the weight of the SID for the purpose of load balancing. The use of the weight is defined in RFC 8402."; reference "RFC 8402: Segment Routing Architecture. Sec. 3.4."; } } Liu, et al. Expires August 26, 2021 [Page 19] Internet-Draft YANG SR MPLS Topology February 2021 } uses information-source-attributes; } // sr } // sr-tp-attributes } 5. IANA Considerations RFC Ed.: In this section, replace all occurrences of 'XXXX' with the actual RFC number (and remove this note). This document registers the following namespace URIs in the IETF XML registry [RFC3688]: -------------------------------------------------------------------- URI: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. -------------------------------------------------------------------- -------------------------------------------------------------------- URI: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology-state Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. -------------------------------------------------------------------- This document registers the following YANG modules in the YANG Module Names registry [RFC6020]: -------------------------------------------------------------------- name: ietf-sr-mpls-topology namespace: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology prefix: srmt reference: RFC XXXX -------------------------------------------------------------------- -------------------------------------------------------------------- name: ietf-sr-mpls-topology-state namespace: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology-state prefix: srmt-s reference: RFC XXXX -------------------------------------------------------------------- Liu, et al. Expires August 26, 2021 [Page 20] Internet-Draft YANG SR MPLS Topology February 2021 6. 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 Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. 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: nw:network-types/l3t:l3-unicast-topology/sr-mpls This subtree specifies the SR MPLS topology type. Modifying the configurations can make SR MPLS topology type invalid and cause interruption to all SR networks. /nw:networks/nw:network/l3t:l3-topology-attributes/sr This subtree specifies the topology-wide configurations, including the SRGB (Segment Routing Global Block). Modifying the configurations here can cause traffic disabled or rerouted in this topology and the connected topologies. /nw:networks/nw:network/nw:node/l3t:l3-node-attributes This subtree specifies the SR configurations for nodes. Modifying the configurations in this subtree can add, remove, or modify SR nodes, causing traffic disabled or rerouted in the specified nodes and the related TE topologies. /nw:networks/nw:network/nt:link/l3t:l3-link-attributes/sr This subtree specifies the configurations for SR Adjacency Segments. Modifying the configurations in this subtree can add, remove, or modify SR Adjacency Segments causing traffic disabled or rerouted on the specified SR adjacencies, the related nodes, and the related SR MPLS topologies. Liu, et al. Expires August 26, 2021 [Page 21] Internet-Draft YANG SR MPLS Topology February 2021 Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability: nw:network-types/l3t:l3-unicast-topology/sr-mpls Unauthorized access to this subtree can disclose the SR MPLS topology type. /nw:networks/nw:network/l3t:l3-topology-attributes/sr Unauthorized access to this subtree can disclose the topology-wide configurations, including the SRGB (Segment Routing Global Block). /nw:networks/nw:network/nw:node/l3t:l3-node-attributes Unauthorized access to this subtree can disclose the operational state information of the SR nodes. /nw:networks/nw:network/nt:link/l3t:l3-link-attributes/sr Unauthorized access to this subtree can disclose the operational state information of SR Adjacency Segments. 7. References 7.1. 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, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . Liu, et al. Expires August 26, 2021 [Page 22] Internet-Draft YANG SR MPLS Topology February 2021 [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [RFC8345] Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March 2018, . [RFC8346] Clemm, A., Medved, J., Varga, R., Liu, X., Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model for Layer 3 Topologies", RFC 8346, DOI 10.17487/RFC8346, March 2018, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [RFC8476] Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak, "Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476, DOI 10.17487/RFC8476, December 2018, . [RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, "Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491, DOI 10.17487/RFC8491, November 2018, . Liu, et al. Expires August 26, 2021 [Page 23] Internet-Draft YANG SR MPLS Topology February 2021 [RFC8814] Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G., and N. Triantafillis, "Signaling Maximum SID Depth (MSD) Using the Border Gateway Protocol - Link State", RFC 8814, DOI 10.17487/RFC8814, August 2020, . [I-D.ietf-spring-sr-yang] Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J. Tantsura, "YANG Data Model for Segment Routing", draft- ietf-spring-sr-yang-30 (work in progress), January 2021. [I-D.ietf-teas-yang-l3-te-topo] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Dios, "YANG Data Model for Layer 3 TE Topologies", draft-ietf-teas-yang-l3-te-topo-09 (work in progress), November 2020. 7.2. Informative References [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, . [RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG", RFC 7951, DOI 10.17487/RFC7951, August 2016, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8665] Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler, H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF Extensions for Segment Routing", RFC 8665, DOI 10.17487/RFC8665, December 2019, . [RFC8666] Psenak, P., Ed. and S. Previdi, Ed., "OSPFv3 Extensions for Segment Routing", RFC 8666, DOI 10.17487/RFC8666, December 2019, . [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, . Liu, et al. Expires August 26, 2021 [Page 24] Internet-Draft YANG SR MPLS Topology February 2021 [RFC8795] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Gonzalez de Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", RFC 8795, DOI 10.17487/RFC8795, August 2020, . [I-D.ietf-idr-bgp-ls-segment-routing-ext] Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., and M. Chen, "BGP Link-State extensions for Segment Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16 (work in progress), June 2019. Liu, et al. Expires August 26, 2021 [Page 25] Internet-Draft YANG SR MPLS Topology February 2021 Appendix A. Companion YANG Model for Non-NMDA Compliant Implementations The YANG module ietf-sr-mpls-topology defined in this document is designed to be used in conjunction with implementations that support the Network Management Datastore Architecture (NMDA) defined in [RFC8342]. In order to allow implementations to use the model even in cases when NMDA is not supported, the following companion module, ietf-sr-mpls-topology-state, is defined as state model, which mirrors the module ietf-sr-mpls-topology defined earlier in this document. However, all data nodes in the companion module are non-configurable, to represent the applied configuration or the derived operational states. The companion module, ietf-sr-mpls-topology-state, is redundant and SHOULD NOT be supported by implementations that support NMDA. As the structure of the companion module mirrors that of the coorespinding NMDA model, the YANG tree of the companion module is not depicted separately. A.1. SR MPLS Topology State Module This module references [RFC8345] and [RFC8346]. file "ietf-sr-mpls-topology-state@2020-11-01.yang" module ietf-sr-mpls-topology-state { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology-state"; prefix "srmt-s"; import ietf-sr-mpls-topology { prefix "srmt"; } import ietf-network-state { prefix "nw-s"; reference "RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-network-topology-state { prefix "nt-s"; reference "RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-l3-unicast-topology-state { prefix "l3t-s"; reference "RFC 8346: A YANG Data Model for Layer 3 Topologies"; } import ietf-segment-routing-common { Liu, et al. Expires August 26, 2021 [Page 26] Internet-Draft YANG SR MPLS Topology February 2021 prefix "sr-cmn"; reference "I-D.ietf-spring-sr-yang: YANG Data Model for Segment Routing"; } organization "IETF Traffic Engineering Architecture and Signaling (TEAS) Working Group"; contact "WG Web: WG List: Editor: Xufeng Liu Editor: Igor Bryskin Editor: Vishnu Pavan Beeram Editor: Tarek Saad Editor: Himanshu Shah Editor: Stephane Litkowski "; description "YANG data model for representing operational state information of Segment Routing Topologies on MPLS data plane, when NMDA is not supported. Copyright (c) 2020 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 Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; Liu, et al. Expires August 26, 2021 [Page 27] Internet-Draft YANG SR MPLS Topology February 2021 revision 2020-11-01 { description "Initial revision"; reference "RFC XXXX: YANG Data Model for SR and SR TE Topologies"; } augment "/nw-s:networks/nw-s:network/nw-s:network-types/" + "l3t-s:l3-unicast-topology" { description "Defines the SR topology type."; uses srmt:sr-mpls-topology-type; } augment "/nw-s:networks/nw-s:network/" + "l3t-s:l3-topology-attributes" { when "../nw-s:network-types/l3t-s:l3-unicast-topology/" + "srmt-s:sr-mpls" { description "Augment only for SR topology."; } description "Augment topology configuration"; uses srmt:sr-mpls-topology-attributes; } augment "/nw-s:networks/nw-s:network/nw-s:node/" + "l3t-s:l3-node-attributes" { when "../../nw-s:network-types/l3t-s:l3-unicast-topology/" + "srmt-s:sr-mpls" { description "Augment only for SR topology."; } description "Augment node configuration."; uses srmt:sr-node-attributes; } augment "/nw-s:networks/nw-s:network/nw-s:node/" + "l3t-s:l3-node-attributes/l3t-s:prefix" { when "../../../nw-s:network-types/l3t-s:l3-unicast-topology/" + "srmt-s:sr-mpls" { description "Augment only for SR topology."; } description "Augment node prefix."; uses srmt:sr-node-prefix-attributes; } augment "/nw-s:networks/nw-s:network/nt-s:link/" + "l3t-s:l3-link-attributes" { when "../../nw-s:network-types/l3t-s:l3-unicast-topology/" + "srmt-s:sr-mpls" { description "Augment only for SR topology."; Liu, et al. Expires August 26, 2021 [Page 28] Internet-Draft YANG SR MPLS Topology February 2021 } description "Augment link configuration"; uses srmt:sr-link-attributes; } grouping sr-mpls-topology-attributes { description "SR topology scope attributes."; container sr-mpls { description "Containing SR attributes."; uses sr-cmn:srgb; } // sr } // sr-mpls-topology-attributes } Appendix B. Data Tree Example This section contains an example of an instance data tree in the JSON encoding [RFC7951]. The example instantiates "ietf-sr-mpls-topology" for the topology that is depicted in the following diagram. +------------+ +------------+ | D1 | | D2 | /-\ /-\ /-\ /-\ | | 1-0-1 | |---------------->| | 2-1-1 | | | | 1-2-1 | |<----------------| | 2-0-1 | | \-/ 1-3-1 \-/ \-/ 2-3-1 \-/ | /----\ | | /----\ | +---| |---+ +---| |---+ \----/ \----/ A | A | | | | | | | | | | | +------------+ | | | | | D3 | | | | | /-\ /-\ | | | +----->| | 3-1-1 | |-------+ | +---------| | 3-2-1 | |<---------+ \-/ \-/ | | +------------+ Liu, et al. Expires August 26, 2021 [Page 29] Internet-Draft YANG SR MPLS Topology February 2021 The corresponding instance data tree is depicted below. Note that some lines have been wrapped to adhere to the 72-character line limitation of RFCs. { "ietf-network:networks": { "network": [ { "network-types": { "ietf-l3-unicast-topology:l3-unicast-topology": { "ietf-sr-mpls-topology:sr-mpls": {} } }, "network-id": "sr-topo-example", "ietf-l3-unicast-topology:l3-topology-attributes": { "ietf-sr-mpls-topology:sr-mpls": { "srgb": [ { "lower-bound": 16000, "upper-bound": 23999 } ] } }, "node": [ { "node-id": "D1", "ietf-network-topology:termination-point": [ { "tp-id": "1-0-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 101 } }, { "tp-id": "1-2-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 121 } }, { "tp-id": "1-3-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 131 } } ], "ietf-l3-unicast-topology:l3-node-attributes": { Liu, et al. Expires August 26, 2021 [Page 30] Internet-Draft YANG SR MPLS Topology February 2021 "router-id": ["203.0.113.1"], "prefix": [ { "prefix": "203.0.113.1/32", "ietf-sr-mpls-topology:sr-mpls": { "start-sid": 101, "range": 1, "is-local": false, "is-node": true } } ], "ietf-sr-mpls-topology:sr-mpls": { "srgb": [ { "lower-bound": 16000, "upper-bound": 23999 } ], "srlb": [ { "lower-bound": 15000, "upper-bound": 15999 } ] } } }, { "node-id": "D2", "ietf-network-topology:termination-point": [ { "tp-id": "2-0-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 201 } }, { "tp-id": "2-1-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 211 } }, { "tp-id": "2-3-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 231 } Liu, et al. Expires August 26, 2021 [Page 31] Internet-Draft YANG SR MPLS Topology February 2021 } ], "ietf-l3-unicast-topology:l3-node-attributes": { "router-id": ["203.0.113.2"], "prefix": [ { "prefix": "203.0.113.2/32", "ietf-sr-mpls-topology:sr-mpls": { "start-sid": 102, "range": 1, "is-local": false, "is-node": true } } ], "ietf-sr-mpls-topology:sr-mpls": { "srgb": [ { "lower-bound": 16000, "upper-bound": 23999 } ], "srlb": [ { "lower-bound": 15000, "upper-bound": 15999 } ] } } }, { "node-id": "D3", "ietf-network-topology:termination-point": [ { "tp-id": "3-1-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 311 } }, { "tp-id": "3-2-1", "ietf-l3-unicast-topology:l3-termination-point-attributes": { "unnumbered-id": 321 } } ], "ietf-l3-unicast-topology:l3-node-attributes": { Liu, et al. Expires August 26, 2021 [Page 32] Internet-Draft YANG SR MPLS Topology February 2021 "router-id": ["203.0.113.3"], "prefix": [ { "prefix": "203.0.113.1/32", "ietf-sr-mpls-topology:sr-mpls": { "start-sid": 101, "range": 1, "is-local": false, "is-node": true } } ], "ietf-sr-mpls-topology:sr-mpls": { "srgb": [ { "lower-bound": 16000, "upper-bound": 23999 } ], "srlb": [ { "lower-bound": 15000, "upper-bound": 15999 } ] } } } ], "ietf-network-topology:link": [ { "link-id": "D1,1-2-1,D2,2-1-1", "source": { "source-node": "D1", "source-tp": "1-2-1" }, "destination": { "dest-node": "D2", "dest-tp": "2-1-1" }, "ietf-l3-unicast-topology:l3-link-attributes": { "metric1": "100", "ietf-sr-mpls-topology:sr-mpls": { "sid": 121, "is-local": true } } }, Liu, et al. Expires August 26, 2021 [Page 33] Internet-Draft YANG SR MPLS Topology February 2021 { "link-id": "D2,2-1-1,D1,1-2-1", "source": { "source-node": "D2", "source-tp": "2-1-1" }, "destination": { "dest-node": "D1", "dest-tp": "1-2-1" }, "ietf-l3-unicast-topology:l3-link-attributes": { "metric1": "100", "ietf-sr-mpls-topology:sr-mpls": { "sid": 211, "is-local": true } } }, { "link-id": "D1,1-3-1,D3,3-1-1", "source": { "source-node": "D1", "source-tp": "1-3-1" }, "destination": { "dest-node": "D3", "dest-tp": "3-1-1" }, "ietf-l3-unicast-topology:l3-link-attributes": { "metric1": "100", "ietf-sr-mpls-topology:sr-mpls": { "sid": 131, "is-local": true } } }, { "link-id": "D3,3-1-1,D1,1-3-1", "source": { "source-node": "D3", "source-tp": "3-1-1" }, "destination": { "dest-node": "D1", "dest-tp": "1-3-1" }, "ietf-l3-unicast-topology:l3-link-attributes": { "metric1": "100", Liu, et al. Expires August 26, 2021 [Page 34] Internet-Draft YANG SR MPLS Topology February 2021 "ietf-sr-mpls-topology:sr-mpls": { "sid": 311, "is-local": true } } }, { "link-id": "D2,2-3-1,D3,3-2-1", "source": { "source-node": "D2", "source-tp": "2-3-1" }, "destination": { "dest-node": "D3", "dest-tp": "3-2-1" }, "ietf-l3-unicast-topology:l3-link-attributes": { "metric1": "100", "ietf-sr-mpls-topology:sr-mpls": { "sid": 231, "is-local": true } } }, { "link-id": "D3,3-2-1,D2,2-3-1", "source": { "source-node": "D3", "source-tp": "3-2-1" }, "destination": { "dest-node": "D2", "dest-tp": "2-3-1" }, "ietf-l3-unicast-topology:l3-link-attributes": { "metric1": "100", "ietf-sr-mpls-topology:sr-mpls": { "sid": 321, "is-local": true } } } ] } ] } } Liu, et al. Expires August 26, 2021 [Page 35] Internet-Draft YANG SR MPLS Topology February 2021 Appendix C. Contributors Jeff Tantsura Email: jefftant.ietf@gmail.com Yingzhen Qu Email: yingzhen.qu@huawei.com Authors' Addresses Xufeng Liu Volta Networks EMail: xufeng.liu.ietf@gmail.com Igor Bryskin Individual EMail: i_bryskin@yahoo.com Vishnu Pavan Beeram Juniper Networks EMail: vbeeram@juniper.net Tarek Saad Juniper Networks EMail: tsaad@juniper.net Himanshu Shah Ciena EMail: hshah@ciena.com Stephane Litkowski Cisco EMail: slitkows.ietf@gmail.com Liu, et al. Expires August 26, 2021 [Page 36]