A YANG Data Model for Traffic Engineering Tunnels, Label Switched Paths and Interfaces

Introduction YANG and is a data modeling language that was introduced to define the contents of a conceptual data store that allows networked devices to be managed using NETCONF . YANG has proved relevant beyond its initial confines, as bindings to other interfaces (e.g. RESTCONF ) and encoding other than XML (e.g. JSON) are being defined. Furthermore, YANG data models can be used as the basis of implementation for other interfaces, such as CLI and programmatic APIs. This document describes a YANG data model for Traffic Engineering (TE) tunnels, Label Switched Paths (LSPs), and interfaces. The data model is divided into two YANG modules. The module 'ietf-te.yang' includes data that is generic and device-independent, while the module 'ietf-te-device.yang' includes data that is device-specific. The document describes a high-level relationship between the modules defined in this document, as well as other external protocol YANG modules. The TE generic YANG data model does not include any data specific to a signaling protocol. It is expected other data plane technology model(s) will augment the TE generic YANG data model. Also, it is expected other YANG modules that model TE signaling protocols, such as RSVP-TE (, ), or Segment-Routing TE (SR-TE) will augment the generic TE YANG module.

Terms and Conventions

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 when, and only when, they appear in all capitals, as shown here.

Terminology The following terms are defined in and are used in this specification: client configuration data state data This document also makes use of the following terminology introduced in the YANG Data Modeling Language : augment data model data node

Prefixes in Data Node Names In this document, names of data nodes and other data model objects are prefixed using the standard prefix associated with the corresponding YANG imported modules, as shown in . Prefix YANG module Reference yang ietf-yang-types inet ietf-inet-types rt-types ietf-routing-types te-types ietf-te-types te-packet-types ietf-te-packet-types te ietf-te this document te-dev ietf-te-device this document

Model Tree Diagrams The tree diagrams extracted from the module(s) defined in this document are given in subsequent sections as per the syntax defined in .

Design Considerations This document describes a generic TE YANG data model that is independent of any dataplane technology. One of the design objectives is to allow specific data plane technology models to reuse the TE generic data model and possibly augment it with technology specific data. The elements of the generic TE YANG data model, including TE Tunnels, LSPs, and interfaces have leaf(s) that identify the technology layer where they reside. For example, the LSP encoding type can identify the technology associated with a TE Tunnel or LSP. Also, the generic TE YANG data model does not cover signaling protocol data. The signaling protocol used to instantiate TE LSPs are outside the scope of this document and expected to be covered by augmentations defined in other document(s). The following other design considerations are taken into account with respect to data organization: The generic TE YANG data model 'ietf-te' contains device independent data and can be used to model data off a device (e.g. on a TE controller). When the model is used to manage a specific device, the model contains the TE Tunnels originating from the specific device. When the model is used to manage a TE controller, the 'tunnels' list contains all TE Tunnels and TE tunnel segments originating from device(s) that the TE controller manages. The device-specific TE data is defined in module 'ietf-te-device' as shown in . In general, minimal elements in the model are designated as "mandatory" to allow freedom to vendors to adapt the data model to their specific product implementation. Suitable defaults are specified for all configurable elements. The model declares a number of TE functions as features that can be optionally supported.

State Data Organization The Network Management Datastore Architecture (NMDA) addresses modeling state data for ephemeral objects. This document adopts the NMDA model for configuration and state data representation as per IETF guidelines for new IETF YANG models.

Model Overview The data models defined in this document cover the core TE features that are commonly supported by different vendor implementations. The support of extended or vendor specific TE feature(s) is expected to either be in augmentations, or deviations to this model that are defined in separate documents.

Module Relationship The generic TE YANG data model that is defined in "ietf-te.yang" covers the building blocks that are device independent and agnostic of any specific technology or control plane instances. The TE device model defined in "ietf-te-device.yang" augments the generic TE YANG data model and covers data that is specific to a device -- for example, attributes of TE interfaces, or TE timers that are local to a TE node. The TE data models for specific instances of data plane technology exist in separate YANG modules that augment the generic TE YANG data model. The TE data models for specific instances of signaling protocols are outside the scope of this document and are defined in other documents. For example, the RSVP-TE YANG model augmentation of the TE model is covered in a separate document.

TE YANG Model The generic TE YANG module ('ietf-te') is meant for the management and operation of a TE network. This includes creating, modifying and retrieving information about TE Tunnels, LSPs, and interfaces and their associated attributes (e.g. Administrative-Groups, SRLGs, etc.). A full tree diagram of the TE model is shown in the Appendix in .

Module Structure The 'te' container is the top level container in the 'ietf-te' module. The presence of the 'te' container enables TE function system wide. Below provides further descriptions of containers that exist under the 'te' top level container. There are three further containers grouped under the 'te' container as shown in and described below. globals:

The 'globals' container maintains the set of global TE attributes that can be applicable to TE Tunnels and interfaces.

tunnels:

The 'tunnels' container includes the list of TE Tunnels that are instantiated. Refer to for further details on the properties of a TE Tunnel.

lsps:

The 'lsps' container includes the list of TE LSP(s) that are instantiated for TE Tunnels. Refer to for further details on the properties of a TE LSP.

The model also contains two Remote Procedure Calls (RPCs) as shown in and described below. tunnels-path-compute:

A RPC to request path computation for a specific TE Tunnel. The RPC allows requesting path computation using atomic and stateless operation. A tunnel may also be configured in 'compute-only' mode to provide stateful path updates - see for further details.

tunnels-action:

An RPC to request a specific action (e.g. reoptimize, or tear-and-setup) to be taken on a specific tunnel or all tunnels.

shows the relationships of these containers and RPCs within the 'ietf-te' module.

TE Globals The 'globals' container covers properties that control a TE feature's behavior system-wide, and its respective state as shown in and described in the text that follows.

named-admin-groups:

A YANG container for the list of named (extended) administrative groups that may be applied to TE links.

named-srlgs:

A YANG container for the list of named Shared Risk Link Groups (SRLGs) that may be applied to TE links.

named-path-constraints:

A YANG container for a list of named path constraints. Each named path constraint is composed of a set of constraints that can be applied during path computation. A named path constraint can be applied to multiple TE Tunnels. Path constraints may also be specified directly under the TE Tunnel. The path constraints specified under the TE Tunnel take precedence over the path constraints derived from the referenced named path constraint. A named path constraint entry can be formed of the path constraints shown in :

- name: A YANG leaf that holds the named path constraint entry. This is unique in the list and used as a key. te-bandwidth: A YANG container that holds the technology agnostic TE bandwidth constraint. link-protection: A YANG leaf that holds the link protection type constraint required for the links to be included in the computed path. setup/hold priority: YANG leafs that hold the LSP setup and hold admission priority as defined in . signaling-type: A YANG leaf that holds the LSP setup type, such as RSVP-TE or SR. path-metric-bounds: A YANG container that holds the set of metric bounds applicable on the computed TE tunnel path. path-affinities-values: A YANG container that holds the set of affinity values and mask to be used during path computation. path-affinity-names: A YANG container that holds the set of named affinity constraints and corresponding inclusion or exclusion instructions for each to be used during path computation. path-srlgs-lists: A YANG container that holds the set of SRLG values and corresponding inclusion or exclusion instructions to be used during path computation. path-srlgs-names: A YANG container that holds the set of named SRLG constraints and corresponding inclusion or exclusion instructions for each to be used during path computation. disjointness: The level of resource disjointness constraint that the secondary path of a TE tunnel has to adhere to. explicit-route-objects-always: A YANG container that contains two route objects lists: 'route-object-exclude-always': a list of route entries to always exclude from the path computation. 'route-object-include-exclude': a list of route entries to include or exclude in the path computation.

- - The 'route-object-include-exclude' is used to configure constraints on which route objects (e.g., nodes, links) are included or excluded in the path computation.

- - The interpretation of an empty 'route-object-include-exclude' list depends on the TE Tunnel (end-to-end or Tunnel Segment) and on the specific path, according to the following rules:

- - An empty 'route-object-include-exclude' list for the primary path of an end-to-end TE Tunnel indicates that there are no route objects to be included or excluded in the path computation. An empty 'route-object-include-exclude' list for the primary path of a TE Tunnel Segment indicates that no primary LSP is required for that TE Tunnel. An empty 'route-object-include-exclude' list for a reverse path means it always follows the forward path (i.e., the TE Tunnel is co-routed). When the 'route-object-include-exclude' list is not empty, the reverse path is routed independently of the forward path. An empty 'route-object-include-exclude' list for the secondary (forward) path indicates that the secondary path has the same endpoints as the primary path.
  path-in-segment: A YANG container that contains a list of label restrictions that have to be taken into considerations when crossing domains. This TE tunnel segment in this case is being stitched to the upstream TE tunnel segment. path-out-segment: A YANG container that contains a list of label restrictions that have to be taken into considerations when crossing domains. The TE tunnel segment in this case is being stitched to the downstream TE tunnel segment.

TE Tunnels The 'tunnels' container holds the list of TE Tunnels that are provisioned on devices in the network as shown in .

When the model is used to manage a specific device, the 'tunnels' list contains the TE Tunnels originating from the specific device. When the model is used to manage a TE controller, the 'tunnels' list contains all TE Tunnels and TE tunnel segments originating from device(s) that the TE controller manages. The TE Tunnel model allows the configuration and management of the following TE tunnel objects: TE Tunnel:

A YANG container of one or more TE LSPs established between the source and destination TE Tunnel termination points.

TE Path:

An engineered path that once instantiated in the forwarding plane can be used to forward traffic from the source to the destination TE Tunnel termination points.

TE LSP:

A TE LSP is a connection-oriented service established over a TE Path and that allows the delivery of traffic between the TE Tunnel source and destination termination points.

TE Tunnel Segment:

A part of a multi-domain TE Tunnel that is within a specific network domain.

The TE Tunnel has a number of attributes that are set directly under the tunnel (as shown in ). The main attributes of a TE Tunnel are described below: operational-state:

A YANG leaf that holds the operational state of the tunnel.

name:

A YANG leaf that holds the name of a TE Tunnel. The name of the TE Tunnel uniquely identifies the tunnel within the TE tunnel list. The name of the TE Tunnel can be formatted as a Uniform Resource Indicator (URI) by including the namespace to ensure uniqueness of the name amongst all the TE Tunnels present on devices and controllers. The configured TE Tunnels can be reported with the name of the device embedded within the TE Tunnel name. For initiated TE Tunnels from the controller, the controller is responsible to ensures that TE Tunnel names are unique.

alias:

A YANG leaf that holds an alternate name to the TE tunnel. Unlike the TE tunnel name, the alias can be modified at any time during the lifetime of the TE tunnel.

identifier:

A YANG leaf that holds an identifier of the tunnel. This identifier is unique amongst tunnels originated from the same ingress device.

color:

A YANG leaf that holds the color associated with the TE tunnel. The color is used to map or steer services that carry matching color on to the TE tunnel as described in .

admin-state:

A YANG leaf that holds the tunnel administrative state. The administrative status in state datastore transitions to 'tunnel-admin-up' when the tunnel used by the client layer, and to 'tunnel-admin-down' when it is not used by the client layer.

operational-state:

A YANG leaf that holds the tunnel operational state.

encoding/switching:

The 'encoding' and 'switching-type' are YANG leafs that define the specific technology in which the tunnel operates in as described in .

source/destination:

YANG leafs that define the tunnel source and destination node endpoints.

src-tunnel-tp-id/dst-tunnel-tp-id:

YANG leafs that hold the identifiers of source and destination TE Tunnel Termination Points (TTPs) residing on the source and destination nodes. The TTP identifiers are optional on nodes that have a single TTP per node. For example, TTP identifiers are optional for packet (IP/MPLS) routers.

bidirectional:

A YANG leaf that when present indicates the LSP of a TE Tunnel is bidirectional and co-routed as defined in .

controller:

A YANG container that holds tunnel data relevant to an optional external TE controller that may initiate or control a tunnel. This target node may be augmented by external module(s), for example, to add data for PCEP initiated and/or delegated tunnels.

reoptimize-timer:

A YANG leaf to set the interval period for tunnel reoptimization.

association-objects:

A YANG container that holds the set of associations of the TE Tunnel to other TE Tunnels. Associations at the TE Tunnel level apply to all paths of the TE Tunnel. The TE tunnel associations can be overridden by associations configured directly under the TE Tunnel path.

protection:

A YANG container that holds the TE Tunnel protection properties.

restoration:

A YANG container that holds the TE Tunnel restoration properties.

te-topology-identifier:

A YANG container that holds the topology identifier associated with the topology where paths for the TE tunnel are computed.

hierarchy:

A YANG container that holds hierarchy related properties of the TE Tunnel. A TE LSP can be set up in MPLS or Generalized MPLS (GMPLS) networks to be used as a TE link to carry traffic in other (client) networks . In this case, the model introduces the TE Tunnel hierarchical link endpoint parameters to identify the specific link in the client layer that the underlying TE Tunnel is associated with. The hierarchy container includes the following:

- dependency-tunnels: A set of hierarchical TE Tunnels provisioned or to be provisioned in the immediate lower layer that this TE tunnel depends on for multi-layer path computation. A dependency TE Tunnel is provisioned if and only if it is used (selected by path computation) at least by one client layer TE Tunnel. The TE link in the client layer network topology supported by a dependent TE Tunnel is dynamically created only when the dependency TE Tunnel is actually provisioned. hierarchical-link: A YANG container that holds the identity of the hierarchical link (in the client layer) that is supported by this TE Tunnel. The endpoints of the hierarchical link are defined by TE tunnel source and destination node endpoints. The hierarchical link can be identified by its source and destination link termination point identifiers.

primary-paths:

A YANG container that holds the list of primary paths. A primary path is identified by 'name'. A primary path is selected from the list to instantiate a primary forwarding LSP for the tunnel. The list of primary paths is visited by order of preference. A primary path has the following attributes:

primary-reverse-path: A YANG container that holds properties of the primary reverse path. The reverse path is applicable to bidirectional TE Tunnels.

candidate-secondary-paths: A YANG container that holds a list of candidate secondary paths which may be used for the primary path to support path protection. The candidate secondary path(s) reference path(s) from the tunnel secondary paths list. The preference of the secondary paths is specified within the list and dictates the order of visiting the secondary path from the list. The attributes of a secondary path can be defined separately from the primary path. The attributes of a secondary path will be inherited from the associated 'active' primary when not explicitly defined for the secondary path.

secondary-paths:

A YANG container that holds the set of secondary paths. A secondary path is identified by 'name'. A secondary path can be referenced from the TE Tunnel's 'candidate-secondary-path' list.

secondary-reverse-paths:

A YANG container that holds the set of secondary reverse paths. A secondary reverse path is identified by 'name'. A secondary reverse path can be referenced from the TE Tunnel's 'candidate-secondary-reverse-paths' list. A secondary reverse path contains attributes similar to a primary path.

The following set of common path attributes are shared for primary (forward and reverse) and secondary paths: path-computation-method:

A YANG leaf that specifies the method used for computing the TE path.

path-computation-server:

A YANG container that holds the path computation server properties when the path is externally queried.

compute-only:

A path of a TE Tunnel is, by default, provisioned so that it can be instantiated in the forwarding plane so that it can carry traffic as soon as a valid path is computed. In some cases, a TE path may be configured only for the purpose of computing a path and reporting it without the need to instantiate the LSP or commit any resources. In such a case, the path is configured in 'compute-only' mode to distinguish it from the default behavior. A 'compute-only' path is configured as a usual with the associated per path constraint(s) and properties on a device or TE controller. The device or TE controller computes the feasible path(s) subject to configured constraints. A client may query the 'compute-only' computed path properties 'on-demand', or alternatively, can subscribe to be notified of computed path(s) and whenever the path properties change.

use-path-computation:

A YANG leaf that indicates whether or not path computation is to be used for a specified path.

lockdown:

A YANG leaf that when set indicates the existing path should not be reoptimized after a failure on any of its traversed links.

path-scope:

A YANG leaf that specifies the path scope if segment or an end-to-end path.

preference:

A YANG leaf that specifies the preference for the path. The lower the number higher the preference.

k-requested-paths:

A YANG leaf that specifies the number of k-shortest-paths requested from the path computation server and returned sorted by its optimization objective.

association-objects:

A YANG container that holds a list of tunnel association properties.

optimizations:

A YANG container that holds the optimization objectives that path computation will use to select a path.

named-path-constraint:

A YANG leafref that references an entry from the global list of named path constraints.

te-bandwidth:

A YANG container that holds the path bandwidth (see ).

link-protection:

A YANG leaf that specifies the link protection type required for the links to be included the computed path (see ).

setup/hold-priority:

see description provided in . These values override those provided in the referenced named-path-constraint.

signaling-type:

see description provided in . This value overrides the provided one in the referenced named-path-constraint.

path-metric-bounds:

see description provided in . These values override those provided in the referenced named-path-constraint.

path-affinities-values:

see description provided in . These values override those provided in the referenced named-path-constraint.

path-affinity-names:

see description provided in . These values override those provided in the referenced named-path-constraint.

path-srlgs-lists:

see description provided in . These values override those provided in the referenced named-path-constraint.

path-srlgs-names:

see description provided in . These values override those provided in the referenced named-path-constraint.

disjointness:

see description provided in . These values override those provided in the referenced named-path-constraint.

explicit-route-objects-always:

see description provided in . These values override those provided in the referenced named-path-constraint.

path-in-segment:

see description provided in . These values override those provided in the referenced named-path-constraint.

path-out-segment:

see description provided in . These values override those provided in the referenced named-path-constraint.

computed-paths-properties:

A YANG container that holds properties for the list of computed paths.

computed-path-error-infos:

A YANG container that holds a list of errors related to the path.

lsp-provisioning-error-infos:

A YANG container that holds the list of LSP provisioning error information.

lsps:

A YANG container that holds a list of LSPs that have been instantiated for this specific path.

In addition to the path common attributes, the primary path has the following attributes that are not present in the secondary path: Only the primary path contains the list of 'candidate-secondary-paths' that can protect the primary path. Only the primary path can contain a primary-reverse-path associated with the primary path (and its associated list of 'candidate-secondary-reverse-path').

TE LSPs The 'lsps' container includes the set of TE LSP(s) that have been instantiated. A TE LSP is identified by a 3-tuple ('tunnel-name', 'lsp-id', 'node'). When the model is used to manage a specific device, the 'lsps' list contains all TE LSP(s) that traverse the device (including ingressing, transiting and egressing the device). When the model is used to manage a TE controller, the 'lsps' list contains all TE LSP(s) that traverse all network devices (including ingressing, transiting and egressing the device) that the TE controller manages.

Tree Diagram shows the tree diagram of depth=4 for the generic TE YANG model defined in modules 'ietf-te.yang'. The full tree diagram is shown in .

YANG Module The generic TE YANG module 'ietf-te' imports the following modules: ietf-yang-types and ietf-inet-types defined in ietf-te-types defined in This module references the following documents: , , , , , , , , , , , , and .

file "ietf-te@2023-03-11.yang" module ietf-te { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-te"; /* Replace with IANA when assigned */ prefix te; /* Import TE generic types */ import ietf-te-types { prefix te-types; reference "RFC8776: Common YANG Data Types for Traffic Engineering."; } import ietf-inet-types { prefix inet; reference "RFC6991: Common YANG Data Types."; } import ietf-yang-types { prefix yang; reference "RFC6991: Common YANG Data Types."; } organization "IETF Traffic Engineering Architecture and Signaling (TEAS) Working Group."; contact "WG Web: WG List: Editor: Tarek Saad Editor: Rakesh Gandhi Editor: Vishnu Pavan Beeram Editor: Himanshu Shah Editor: Xufeng Liu Editor: Igor Bryskin "; description "YANG data module for TE configuration, state, and RPCs. The model fully conforms to the Network Management Datastore Architecture (NMDA). Copyright (c) 2023 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."; // RFC Ed.: replace XXXX with actual RFC number and remove this // note. // RFC Ed.: update the date below with the date of RFC publication // and remove this note. revision 2023-03-11 { description "Initial revision for the TE generic YANG module."; reference "RFCXXXX: A YANG Data Model for Traffic Engineering Tunnels and Interfaces."; } typedef tunnel-ref { type leafref { path "/te:te/te:tunnels/te:tunnel/te:name"; } description "This type is used by data models that need to reference configured TE tunnel."; } typedef te-gen-node-id { type union { type te-types:te-node-id; type inet:ip-address; } description "Generic type that identifies a node in a TE topology."; } /** * TE tunnel generic groupings */ grouping te-generic-node-id { description "A reusable grouping for a TE generic node identifier."; leaf id { type te-gen-node-id; description "The identifier of the node. Can be represented as IP address or dotted quad address."; } leaf type { type enumeration { enum ip { description "IP address representation of the node identifier."; } enum dotted-quad { description "Dotted quad address representation of the node identifier."; } } description "Type of node identifier representation."; } } grouping path-common-properties { description "Common path attributes."; leaf name { type string; description "TE path name."; } leaf path-computation-method { type identityref { base te-types:path-computation-method; } default "te-types:path-locally-computed"; description "The method used for computing the path, either locally computed, queried from a server or not computed at all (explicitly configured)."; } container path-computation-server { when "derived-from-or-self(../path-computation-method, " + "'te-types:path-externally-queried')" { description "The path-computation server when the path is externally queried."; } uses te-generic-node-id; description "Address of the external path computation server."; } leaf compute-only { type empty; description "When present, the path is computed and updated whenever the topology is updated. No resources are committed or reserved in the network."; } leaf use-path-computation { when "derived-from-or-self(../path-computation-method, " + "'te-types:path-locally-computed')"; type boolean; default "true"; description "When 'true' indicates the path is dynamically computed and/or validated against the Traffic-Engineering Database (TED), and when 'false' indicates no path expansion or validation against the TED is required."; } leaf lockdown { type empty; description "When present, indicates no reoptimization to be attempted for this path."; } leaf path-scope { type identityref { base te-types:path-scope-type; } default "te-types:path-scope-end-to-end"; config false; description "Indicates whether the path is a segment or portion of of the full path., or is the an end-to-end path for the TE Tunnel."; } } /* This grouping is re-used in path-computation rpc */ grouping path-compute-info { description "Attributes used for path computation request."; uses tunnel-associations-properties; uses te-types:generic-path-optimization; leaf named-path-constraint { if-feature "te-types:named-path-constraints"; type leafref { path "/te:te/te:globals/te:named-path-constraints/" + "te:named-path-constraint/te:name"; } description "Reference to a globally defined named path constraint set."; } uses path-constraints-common; } /* This grouping is re-used in path-computation rpc */ grouping path-forward-properties { description "The path preference."; leaf preference { type uint8 { range "1..255"; } default "1"; description "Specifies a preference for this path. The lower the number higher the preference."; } leaf co-routed { when "/te:te/te:tunnels/te:tunnel/te:bidirectional = 'true'" { description "Applicable to bidirectional tunnels only."; } type boolean; default "false"; description "Indicates whether the reverse path must to be co-routed with the primary."; } } /* This grouping is re-used in path-computation rpc */ grouping k-requested-paths { description "The k-shortest paths requests."; leaf k-requested-paths { type uint8; default "1"; description "The number of k-shortest-paths requested from the path computation server and returned sorted by its optimization objective."; } } grouping path-state { description "TE per path state parameters."; uses path-computation-response; container lsp-provisioning-error-infos { config false; description "LSP provisioning error information."; list lsp-provisioning-error-info { description "List of LSP provisioning error info entries."; leaf error-reason { type identityref { base te-types:lsp-provisioning-error-reason; } description "LSP provision error type."; } leaf error-description { type string; description "The textual representation of the error occurred during path computation."; } leaf error-timestamp { type yang:date-and-time; description "Timestamp of when the reported error occurred."; } leaf error-node-id { type te-types:te-node-id; description "Node identifier of node where error occurred."; } leaf error-link-id { type te-types:te-tp-id; description "Link ID where the error occurred."; } leaf lsp-id { type uint16; description "The LSP-ID for which path computation was performed."; } } } container lsps { config false; description "The TE LSPs container."; list lsp { key "node lsp-id"; description "List of LSPs associated with the tunnel."; leaf tunnel-name { type leafref { path "/te:te/te:lsps/te:lsp/te:tunnel-name"; } description "TE tunnel name."; } leaf node { type leafref { path "/te:te/te:lsps/te:lsp[tunnel-name=" + "current()/../te:tunnel-name][lsp-id=" + "current()/../te:lsp-id]/te:node"; } description "The node where the LSP state resides on."; } leaf lsp-id { type leafref { path "/te:te/te:lsps/te:lsp[tunnel-name=" + "current()/../tunnel-name]/te:lsp-id"; } description "The TE LSP identifier."; } } } } /* This grouping is re-used in path-computation rpc */ grouping path-computation-response { description "Attributes reported by path computation response."; container computed-paths-properties { config false; description "Computed path properties container."; list computed-path-properties { key "k-index"; description "List of computed paths."; leaf k-index { type uint8; description "The k-th path returned from the computation server. A lower k value path is more optimal than higher k value path(s)"; } uses te-types:generic-path-properties { augment "path-properties" { description "additional path properties returned by path computation."; uses te-types:te-bandwidth; leaf disjointness-type { type te-types:te-path-disjointness; config false; description "The type of resource disjointness. When reported for a primary path, it represents the minimum level of disjointness of all the secondary paths. When reported for a secondary path, it represents the disjointness of the secondary path."; } } } } } container computed-path-error-infos { config false; description "Path computation information container."; list computed-path-error-info { description "List of path computation info entries."; leaf error-description { type string; description "Textual representation of the error occurred during path computation."; } leaf error-timestamp { type yang:date-and-time; description "Timestamp of last path computation attempt."; } leaf error-reason { type identityref { base te-types:path-computation-error-reason; } description "Reason for the path computation error."; } } } } grouping protection-restoration-properties { description "Protection and restoration parameters."; container protection { description "Protection parameters."; leaf protection-type { type identityref { base te-types:lsp-protection-type; } default "te-types:lsp-protection-unprotected"; description "LSP protection type."; } leaf protection-reversion-disable { type boolean; default "false"; description "Disable protection reversion to working path."; } leaf hold-off-time { type uint32; units "milli-seconds"; description "The time between the declaration of an SF or SD condition and the initialization of the protection switching algorithm."; reference "RFC4427"; } leaf wait-to-revert { type uint16; units "seconds"; description "Time to wait before attempting LSP reversion."; reference "RFC4427"; } leaf aps-signal-id { type uint8 { range "1..255"; } default "1"; description "The APS signal number used to reference the traffic of this tunnel. The default value for normal traffic is 1. The default value for extra-traffic is 255. If not specified, non-default values can be assigned by the server, if and only if, the server controls both endpoints."; reference "RFC4427"; } } container restoration { description "Restoration parameters."; leaf restoration-type { type identityref { base te-types:lsp-restoration-type; } default "te-types:lsp-restoration-restore-none"; description "LSP restoration type."; } leaf restoration-scheme { type identityref { base te-types:restoration-scheme-type; } default "te-types:restoration-scheme-preconfigured"; description "LSP restoration scheme."; } leaf restoration-reversion-disable { type boolean; default "false"; description "Disable restoration reversion to working path."; } leaf hold-off-time { type uint32; units "milli-seconds"; description "The time between the declaration of an SF or SD condition and the initialization of the protection switching algorithm."; reference "RFC4427"; } leaf wait-to-restore { type uint16; units "seconds"; description "Time to wait before attempting LSP restoration."; reference "RFC4427"; } leaf wait-to-revert { type uint16; units "seconds"; description "Time to wait before attempting LSP reversion."; reference "RFC4427"; } } } grouping tunnel-associations-properties { description "TE tunnel association grouping."; container association-objects { description "TE tunnel associations."; list association-object { key "association-key"; unique "type id source/id source/type"; description "List of association base objects."; reference "RFC4872"; leaf association-key { type string; description "Association key used to identify a specific association in the list"; } leaf type { type identityref { base te-types:association-type; } description "Association type."; reference "RFC4872"; } leaf id { type uint16; description "Association identifier."; reference "RFC4872"; } container source { uses te-generic-node-id; description "Association source."; reference "RFC4872"; } } list association-object-extended { key "association-key"; unique "type id source/id source/type global-source extended-id"; description "List of extended association objects."; reference "RFC6780"; leaf association-key { type string; description "Association key used to identify a specific association in the list"; } leaf type { type identityref { base te-types:association-type; } description "Association type."; reference "RFC4872, RFC6780"; } leaf id { type uint16; description "Association identifier."; reference "RFC4872, RFC6780"; } container source { uses te-generic-node-id; description "Association source."; reference "RFC4872, RFC6780"; } leaf global-source { type uint32; description "Association global source."; reference "RFC6780"; } leaf extended-id { type yang:hex-string; description "Association extended identifier."; reference "RFC6780"; } } } } /* This grouping is re-used in path-computation rpc */ grouping tunnel-common-attributes { description "Common grouping to define the TE tunnel parameters"; leaf source { type te-types:te-node-id; description "TE tunnel source node ID."; } leaf destination { type te-types:te-node-id; description "TE tunnel destination node identifier."; } leaf src-tunnel-tp-id { type binary; description "TE tunnel source termination point identifier."; } leaf dst-tunnel-tp-id { type binary; description "TE tunnel destination termination point identifier."; } leaf bidirectional { type boolean; default "false"; description "Indicates a bidirectional co-routed LSP (non-associated LSP case)."; } } /* This grouping is re-used in path-computation rpc */ grouping tunnel-hierarchy-properties { description "A grouping for TE tunnel hierarchy information."; container hierarchy { description "Container for TE hierarchy related information."; container dependency-tunnels { description "List of tunnels that this tunnel can be potentially dependent on."; list dependency-tunnel { key "name"; description "A tunnel entry that this tunnel can potentially depend on."; leaf name { type leafref { path "/te:te/te:tunnels/te:tunnel/te:name"; require-instance false; } description "Dependency tunnel name. The tunnel may not have been instantiated yet."; } uses te-types:encoding-and-switching-type; } } container hierarchical-link { description "Identifies a hierarchical link (in client layer) that this tunnel is associated with. By default, the topology of the hierarchical link is the same topology of the tunnel;"; reference "RFC4206"; leaf enable { type boolean; description "Enables the hierarchical link properties supported by this tunnel"; } leaf local-te-node-id { type te-types:te-node-id; description "The local TE node identifier."; } leaf local-te-link-tp-id { type te-types:te-tp-id; description "The local TE link termination point identifier."; } leaf remote-te-node-id { type te-types:te-node-id; description "Remote TE node identifier."; } uses te-types:te-topology-identifier { description "The topology identifier where the hierarchical link supported by this TE tunnel is instantiated."; } } } } grouping path-constraints-common { description "Global named path constraints configuration grouping."; uses te-types:common-path-constraints-attributes { description "The constraints applicable to the path. This includes: - The path bandwidth constraint - The path link protection type constraint - The path setup/hold priority constraint - path signaling type constraint - path metric bounds constraint. The unit of path metric bound is interpreted in the context of the metric-type. For example for metric-type 'path-metric-loss', the bound is multiples of the basic unit 0.000003% as described in RFC7471 for OSPF, and RFC8570 for ISIS. - path affinity constraints - path SRLG constraints"; } uses te-types:generic-path-disjointness; uses te-types:path-constraints-route-objects; container path-in-segment { presence "The end-to-end tunnel starts in a previous domain; this tunnel is a segment in the current domain."; description "If an end-to-end tunnel crosses multiple domains using the same technology, some additional constraints have to be taken in consideration in each domain. This TE tunnel segment is stitched to the upstream TE tunnel segment."; uses te-types:label-set-info; } container path-out-segment { presence "The end-to-end tunnel is not terminated in this domain; this tunnel is a segment in the current domain."; description "If an end-to-end tunnel crosses multiple domains using the same technology, some additional constraints have to be taken in consideration in each domain. This TE tunnel segment is stitched to the downstream TE tunnel segment."; uses te-types:label-set-info; } } /** * TE container */ container te { description "TE global container."; leaf enable { type boolean; default "false"; description "Enables the TE component features."; } /* TE Global Data */ container globals { description "Globals TE system-wide configuration data container."; container named-admin-groups { description "TE named admin groups container."; list named-admin-group { if-feature "te-types:extended-admin-groups"; if-feature "te-types:named-extended-admin-groups"; key "name"; description "List of named TE admin-groups."; leaf name { type string; description "A string name that uniquely identifies a TE interface named admin-group."; } leaf bit-position { type uint32; description "Bit position representing the administrative group."; reference "RFC3209 and RFC7308"; } } } container named-srlgs { description "TE named SRLGs container."; list named-srlg { if-feature "te-types:named-srlg-groups"; key "name"; description "A list of named SRLG groups."; leaf name { type string; description "A string name that uniquely identifies a TE interface named SRLG."; } leaf value { type te-types:srlg; description "An SRLG value."; } leaf cost { type uint32; description "SRLG associated cost. Used during path to append the path cost when traversing a link with this SRLG."; } } } container named-path-constraints { description "TE named path constraints container."; list named-path-constraint { if-feature "te-types:named-path-constraints"; key "name"; leaf name { type string; description "A string name that uniquely identifies a path constraint set."; } uses path-constraints-common; description "A list of named path constraints."; } } } /* TE Tunnel Data */ container tunnels { description "Tunnels TE configuration data container."; list tunnel { key "name"; description "The list of TE tunnels."; leaf name { type string; description "TE tunnel name."; } leaf alias { type string; description "An alternate name of the TE tunnel that can be modified anytime during its lifetime."; } leaf identifier { type uint32; description "TE tunnel Identifier."; reference "RFC3209"; } leaf color { type uint32; description "The color associated with the TE tunnel."; reference "RFC9012"; } leaf description { type string; default "None"; description "Textual description for this TE tunnel."; } leaf admin-state { type identityref { base te-types:tunnel-admin-state-type; } default "te-types:tunnel-admin-state-up"; description "TE tunnel administrative state."; } leaf operational-state { type identityref { base te-types:tunnel-state-type; } config false; description "TE tunnel operational state."; } uses te-types:encoding-and-switching-type; uses tunnel-common-attributes; container controller { description "Contains tunnel data relevant to external controller(s). This target node may be augmented by external module(s), for example, to add data for PCEP initiated and/or delegated tunnels."; leaf protocol-origin { type identityref { base te-types:protocol-origin-type; } description "The protocol origin for instantiating the tunnel."; } leaf controller-entity-id { type string; description "An identifier unique within the scope of visibility that associated with the entity that controls the tunnel."; reference "RFC8232"; } } leaf reoptimize-timer { type uint16; units "seconds"; description "Frequency of reoptimization of a traffic engineered LSP."; } uses tunnel-associations-properties; uses protection-restoration-properties; uses te-types:tunnel-constraints; uses tunnel-hierarchy-properties; container primary-paths { description "The set of primary paths."; reference "RFC4872"; list primary-path { key "name"; description "List of primary paths for this tunnel."; uses path-common-properties; uses path-forward-properties; uses k-requested-paths; uses path-compute-info; uses path-state; container primary-reverse-path { when "../../../te:bidirectional = 'false'"; description "The reverse primary path properties."; uses path-common-properties; uses path-compute-info; uses path-state; container candidate-secondary-reverse-paths { when "../../../../te:bidirectional = 'false'"; description "The set of referenced candidate reverse secondary paths from the full set of secondary reverse paths which may be used for this primary path."; list candidate-secondary-reverse-path { key "secondary-path"; ordered-by user; description "List of candidate secondary reverse path(s)"; leaf secondary-path { type leafref { path "../../../../../../" + "te:secondary-reverse-paths/" + "te:secondary-reverse-path/te:name"; } description "A reference to the secondary reverse path that should be utilised when the containing primary reverse path option is in use."; } } } } container candidate-secondary-paths { description "The set of candidate secondary paths which may be used for this primary path. When secondary paths are specified in the list the path of the secondary LSP in use must be restricted to those path options referenced. The priority of the secondary paths is specified within the list. Higher priority values are less preferred - that is to say that a path with priority 0 is the most preferred path. In the case that the list is empty, any secondary path option may be utilised when the current primary path is in use."; list candidate-secondary-path { key "secondary-path"; ordered-by user; description "List of candidate secondary paths for this tunnel."; leaf secondary-path { type leafref { path "../../../../../te:secondary-paths/" + "te:secondary-path/te:name"; } description "A reference to the secondary path that should be utilised when the containing primary path option is in use."; } leaf active { type boolean; config false; description "Indicates the current active path option that has been selected of the candidate secondary paths."; } } } } } container secondary-paths { description "The set of secondary paths."; reference "RFC4872"; list secondary-path { key "name"; description "List of secondary paths for this tunnel."; uses path-common-properties; leaf preference { type uint8 { range "1..255"; } default "1"; description "Specifies a preference for this path. The lower the number higher the preference."; } uses path-compute-info; uses protection-restoration-properties; uses path-state; } } container secondary-reverse-paths { description "The set of secondary reverse paths."; list secondary-reverse-path { key "name"; description "List of secondary paths for this tunnel."; uses path-common-properties; leaf preference { type uint8 { range "1..255"; } default "1"; description "Specifies a preference for this path. The lower the number higher the preference. Paths that have the same preference will be activated together."; } uses path-compute-info; uses protection-restoration-properties; uses path-state; } } action tunnel-action { description "Tunnel action."; input { leaf action-type { type identityref { base te-types:tunnel-action-type; } description "Tunnel action type."; } } output { leaf action-result { type identityref { base te-types:te-action-result; } description "The result of the tunnel action operation."; } } } action protection-external-commands { input { leaf protection-external-command { type identityref { base te-types:protection-external-commands; } description "Protection external command."; } leaf protection-group-ingress-node { type boolean; default "true"; description "When 'true', indicates that the action is applied on ingress node. By default, the action applies to the ingress node only."; } leaf protection-group-egress-node { type boolean; default "false"; description "When set to 'true', indicates that the action is applied on egress node. By default, the action applies to the ingress node only."; } leaf path-name { type string; description "The name of the path that the external command applies to."; } leaf path-type { type te-types:path-type; description "The type of the path that the external command applies to."; } leaf traffic-type { type enumeration { enum normal-traffic { description "The manual-switch or forced-switch command applies to the normal traffic (this Tunnel)."; } enum null-traffic { description "The manual-switch or forced-switch command applies to the null traffic."; } enum extra-traffic { description "The manual-switch or forced-switch command applies to the extra traffic (the extra-traffic Tunnel sharing protection bandwidth with this Tunnel)."; } } description "Indicates whether the manual-switch or forced-switch commands applies to the normal traffic, the null traffic or the extra-traffic."; reference "RFC4427"; } leaf extra-traffic-tunnel-ref { type tunnel-ref; description "In case there are multiple extra-traffic tunnels sharing protection bandwidth with this Tunnel (m:n protection), represents which extra-traffic Tunnel the manual-switch or forced-switch to extra-traffic command applies to."; } } } } } /* TE LSPs Data */ container lsps { config false; description "TE LSPs state container."; list lsp { key "tunnel-name lsp-id node"; unique "source destination tunnel-id lsp-id " + "extended-tunnel-id"; description "List of LSPs associated with the tunnel."; leaf tunnel-name { type string; description "The TE tunnel name."; } leaf lsp-id { type uint16; description "Identifier used in the SENDER_TEMPLATE and the FILTER_SPEC that can be changed to allow a sender to share resources with itself."; reference "RFC3209"; } leaf node { type te-types:te-node-id; description "The node where the TE LSP state resides on."; } leaf source { type te-types:te-node-id; description "Tunnel sender address extracted from SENDER_TEMPLATE object."; reference "RFC3209"; } leaf destination { type te-types:te-node-id; description "The tunnel endpoint address."; reference "RFC3209"; } leaf tunnel-id { type uint16; description "The tunnel identifier that remains constant over the life of the tunnel."; reference "RFC3209"; } leaf extended-tunnel-id { type yang:dotted-quad; description "The LSP Extended Tunnel ID."; reference "RFC3209"; } leaf operational-state { type identityref { base te-types:lsp-state-type; } description "The LSP operational state."; } leaf signaling-type { type identityref { base te-types:path-signaling-type; } description "The signaling protocol used to set up this LSP."; } leaf origin-type { type enumeration { enum ingress { description "Origin ingress."; } enum egress { description "Origin egress."; } enum transit { description "Origin transit."; } } description "The origin of the LSP relative to the location of the local switch in the path."; } leaf lsp-resource-status { type enumeration { enum primary { description "A primary LSP is a fully established LSP for which the resource allocation has been committed at the data plane."; } enum secondary { description "A secondary LSP is an LSP that has been provisioned in the control plane only; e.g. resource allocation has not been committed at the data plane."; } } description "LSP resource allocation state."; reference "RFC4872, section 4.2.1"; } leaf lockout-of-normal { type boolean; description "When set to 'true', it represents a lockout of normal traffic external command. When set to 'false', it represents a clear lockout of normal traffic external command. The lockout of normal traffic command applies to this Tunnel."; reference "RFC4427"; } leaf freeze { type boolean; description "When set to 'true', it represents a freeze external command. When set to 'false', it represents a clear freeze external command. The freeze command applies to all the Tunnels which are sharing the protection resources with this Tunnel."; reference "RFC4427"; } leaf lsp-protection-role { type enumeration { enum working { description "A working LSP must be a primary LSP whilst a protecting LSP can be either a primary or a secondary LSP. Also, known as protected LSPs when working LSPs are associated with protecting LSPs."; } enum protecting { description "A secondary LSP is an LSP that has been provisioned in the control plane only; e.g. resource allocation has not been committed at the data plane."; } } description "LSP role type."; reference "RFC4872, section 4.2.1"; } leaf lsp-protection-state { type identityref { base te-types:lsp-protection-state; } description "The APS state machine controlling which tunnels are using the resources of the protecting LSP."; reference "ITU_G.808.1, RFC7271, and RFC8234"; } leaf protection-group-ingress-node-id { type te-types:te-node-id; description "Indicates the te-node-id of the protection group ingress node when the APS state represents an external command (LoP, SF, MS) applied to it or a WTR timer running on it. If the external command is not applied to the ingress node or the WTR timer is not running on it, this attribute is not specified. A value 0.0.0.0 is used when the te-node-id of the protection group ingress node is unknown (e.g., because the ingress node is outside the scope of control of the server)"; } leaf protection-group-egress-node-id { type te-types:te-node-id; description "Indicates the te-node-id of the protection group egress node when the APS state represents an external command (LoP, SF, MS) applied to it or a WTR timer running on it. If the external command is not applied to the ingress node or the WTR timer is not running on it, this attribute is not specified. A value 0.0.0.0 is used when the te-node-id of the protection group ingress node is unknown (e.g., because the ingress node is outside the scope of control of the server)"; } container lsp-actual-route-information { description "RSVP recorded route object information."; list lsp-actual-route-information { when "../../origin-type = 'ingress'" { description "Applicable on ingress LSPs only."; } key "index"; description "Record route list entry."; uses te-types:record-route-state; } } } } } /* TE Tunnel RPCs/execution Data */ rpc tunnels-path-compute { description "TE tunnels RPC nodes."; input { container path-compute-info { /* * An external path compute module may augment this * target. */ description "RPC input information."; } } output { container path-compute-result { /* * An external path compute module may augment this * target. */ description "RPC output information."; } } } rpc tunnels-actions { description "TE tunnels actions RPC"; input { container tunnel-info { description "TE tunnel information."; choice filter-type { mandatory true; description "Filter choice."; case all-tunnels { leaf all { type empty; mandatory true; description "When present, applies the action on all TE tunnels."; } } case one-tunnel { leaf tunnel { type tunnel-ref; description "Apply action on the specific TE tunnel."; } } } } container action-info { description "TE tunnel action information."; leaf action { type identityref { base te-types:tunnel-action-type; } description "The action type."; } leaf disruptive { when "derived-from-or-self(../action, " + "'te-types:tunnel-action-reoptimize')"; type empty; description "When present, specifies whether or not the reoptimization action is allowed to be disruptive."; } } } output { leaf action-result { type identityref { base te-types:te-action-result; } description "The result of the tunnel action operation."; } } } }

]]>


TE Device YANG Model

The device TE YANG module ('ietf-te-device') models data that is specific to
managing a TE device.  This module augments the generic TE YANG module.

Module Structure

TE Interfaces

This branch of the model manages TE interfaces that are present on a device. 
Examples of TE interface properties are:


  Maximum reservable bandwidth, bandwidth constraints (BC)
  Flooding parameters
  
      Flooding intervals and threshold values
    
  Interface attributes
  
      (Extended) administrative groups
      SRLG values
      TE metric value
    
  Fast reroute backup tunnel properties (such as static, auto-tunnel)


The derived state associated with interfaces is grouped under the interface
"state" sub-container as shown in .  This covers state data
such as:


  Bandwidth information: maximum bandwidth, available bandwidth at different
priorities and for each class-type (CT)
  List of admitted LSPs
  
      Name, bandwidth value and pool, time, priority
    
  Statistics: state counters, flooding counters, admission counters
(accepted/rejected), preemption counters
  Adjacency information
  
      Neighbor address
      Metric value
    


>
             .
             +-- ro state
                <>
]]>



Tree Diagram

 shows the tree diagram of the device TE YANG model defined in
modules 'ietf-te-device.yang'.




YANG Module

The device TE YANG module 'ietf-te-device' imports the following module(s):


  ietf-interfaces defined in 
  ietf-routing-types defined in 
  ietf-te-types defined in 
  ietf-te defined in this document


 file "ietf-te-device@2023-03-11.yang"
module ietf-te-device {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-te-device";

  /* Replace with IANA when assigned */

  prefix te-dev;

  /* Import TE module */

  import ietf-te {
    prefix te;
    reference
      "RFCXXXX: A YANG Data Model for Traffic Engineering
       Tunnels and Interfaces";
  }

  /* Import TE types */

  import ietf-te-types {
    prefix te-types;
    reference
      "RFC8776: Common YANG Data Types for Traffic Engineering.";
  }
  import ietf-interfaces {
    prefix if;
    reference
      "RFC8343: A YANG Data Model for Interface Management";
  }
  import ietf-routing-types {
    prefix rt-types;
    reference
      "RFC8294: Common YANG Data Types for the Routing Area";
  }

  organization
    "IETF Traffic Engineering Architecture and Signaling (TEAS)
     Working Group";
  contact
    "WG Web:   
     WG List:  

     Editor:   Tarek Saad
               

     Editor:   Rakesh Gandhi
               

     Editor:   Vishnu Pavan Beeram
               

     Editor:   Himanshu Shah
               

     Editor:   Xufeng Liu
               

     Editor:   Igor Bryskin
               ";
  description
    "This module defines a data model for TE device configurations,
     state, and RPCs. The model fully conforms to the
     Network Management Datastore Architecture (NMDA).

     Copyright (c) 2023 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.";

  // RFC Ed.: replace XXXX with actual RFC number and remove this
  // note.
  // RFC Ed.: update the date below with the date of RFC publication
  // and remove this note.

  revision 2023-03-11 {
    description
      "Initial revision for the TE device YANG module.";
    reference
      "RFCXXXX: A YANG Data Model for Traffic Engineering Tunnels
       and Interfaces";
  }

  grouping lsp-device-timers {
    description
      "Device TE LSP timers configs.";
    leaf lsp-install-interval {
      type uint32;
      units "seconds";
      description
        "TE LSP installation delay time.";
    }
    leaf lsp-cleanup-interval {
      type uint32;
      units "seconds";
      description
        "TE LSP cleanup delay time.";
    }
    leaf lsp-invalidation-interval {
      type uint32;
      units "seconds";
      description
        "TE LSP path invalidation before taking action delay time.";
    }
  }

  grouping te-igp-flooding-bandwidth-config {
    description
      "Configurable items for igp flooding bandwidth
       threshold configuration.";
    leaf threshold-type {
      type enumeration {
        enum delta {
          description
            "'delta' indicates that the local
             system should flood IGP updates when a
             change in reserved bandwidth >= the specified
             delta occurs on the interface.";
        }
        enum threshold-crossed {
          description
            "THRESHOLD-CROSSED indicates that
             the local system should trigger an update (and
             hence flood) the reserved bandwidth when the
             reserved bandwidth changes such that it crosses,
             or becomes equal to one of the threshold values.";
        }
      }
      description
        "The type of threshold that should be used to specify the
         values at which bandwidth is flooded. 'delta' indicates that
         the local system should flood IGP updates when a change in
         reserved bandwidth >= the specified delta occurs on the
         interface. Where 'threshold-crossed' is specified, the local
         system should trigger an update (and hence flood) the
         reserved bandwidth when the reserved bandwidth changes such
         that it crosses, or becomes equal to one of the threshold
         values.";
    }
    leaf delta-percentage {
      when "../threshold-type = 'delta'" {
        description
          "The percentage delta can only be specified when the
           threshold type is specified to be a percentage delta of
           the reserved bandwidth.";
      }
      type rt-types:percentage;
      description
        "The percentage of the maximum-reservable-bandwidth
         considered as the delta that results in an IGP update
         being flooded.";
    }
    leaf threshold-specification {
      when "../threshold-type = 'threshold-crossed'" {
        description
          "The selection of whether mirrored or separate threshold
           values are to be used requires user specified thresholds
           to be set.";
      }
      type enumeration {
        enum mirrored-up-down {
          description
            "mirrored-up-down indicates that a single set of
             threshold values should be used for both increasing
             and decreasing bandwidth when determining whether
             to trigger updated bandwidth values to be flooded
             in the IGP TE extensions.";
        }
        enum separate-up-down {
          description
            "separate-up-down indicates that a separate
             threshold values should be used for the increasing
             and decreasing bandwidth when determining whether
             to trigger updated bandwidth values to be flooded
             in the IGP TE extensions.";
        }
      }
      description
        "This value specifies whether a single set of threshold
         values should be used for both increasing and decreasing
         bandwidth when determining whether to trigger updated
         bandwidth values to be flooded in the IGP TE extensions.
         'mirrored-up-down' indicates that a single value (or set of
         values) should be used for both increasing and decreasing
         values, where 'separate-up-down' specifies that the
         increasing and decreasing values will be separately
         specified.";
    }
    leaf-list up-thresholds {
      when "../threshold-type = 'threshold-crossed'"
         + "and ../threshold-specification = 'separate-up-down'" {
        description
          "A list of up-thresholds can only be specified when the
           bandwidth update is triggered based on crossing a
           threshold and separate up and down thresholds are
           required.";
      }
      type rt-types:percentage;
      description
        "The thresholds (expressed as a percentage of the maximum
         reservable bandwidth) at which bandwidth updates are to be
         triggered when the bandwidth is increasing.";
    }
    leaf-list down-thresholds {
      when "../threshold-type = 'threshold-crossed'"
         + "and ../threshold-specification = 'separate-up-down'" {
        description
          "A list of down-thresholds can only be specified when the
           bandwidth update is triggered based on crossing a
           threshold and separate up and down thresholds are
           required.";
      }
      type rt-types:percentage;
      description
        "The thresholds (expressed as a percentage of the maximum
         reservable bandwidth) at which bandwidth updates are to be
         triggered when the bandwidth is decreasing.";
    }
    leaf-list up-down-thresholds {
      when "../threshold-type = 'threshold-crossed'"
         + "and ../threshold-specification = 'mirrored-up-down'" {
        description
          "A list of thresholds corresponding to both increasing
           and decreasing bandwidths can be specified only when an
           update is triggered based on crossing a threshold, and
           the same up and down thresholds are required.";
      }
      type rt-types:percentage;
      description
        "The thresholds (expressed as a percentage of the maximum
         reservable bandwidth of the interface) at which bandwidth
         updates are flooded - used both when the bandwidth is
         increasing and decreasing.";
    }
  }

  /**
   * TE device augmentations
   */
  augment "/te:te" {
    description
      "TE global container.";
    /* TE Interface Configuration Data */
    container interfaces {
      description
        "Configuration data model for TE interfaces.";
      uses te-igp-flooding-bandwidth-config;
      list interface {
        key "interface";
        description
          "TE interfaces.";
        leaf interface {
          type if:interface-ref;
          description
            "TE interface name.";
        }
        /* TE interface parameters */
        leaf te-metric {
          type te-types:te-metric;
          description
            "TE interface metric.";
        }
        choice admin-group-type {
          description
            "TE interface administrative groups
             representation type.";
          case value-admin-groups {
            choice value-admin-group-type {
              description
                "choice of admin-groups.";
              case admin-groups {
                description
                  "Administrative group/Resource
                   class/Color.";
                leaf admin-group {
                  type te-types:admin-group;
                  description
                    "TE interface administrative group.";
                }
              }
              case extended-admin-groups {
                if-feature "te-types:extended-admin-groups";
                description
                  "Extended administrative group/Resource
                   class/Color.";
                leaf extended-admin-group {
                  type te-types:extended-admin-group;
                  description
                    "TE interface extended administrative group.";
                }
              }
            }
          }
          case named-admin-groups {
            list named-admin-groups {
              if-feature "te-types:extended-admin-groups";
              if-feature "te-types:named-extended-admin-groups";
              key "named-admin-group";
              description
                "A list of named admin-group entries.";
              leaf named-admin-group {
                type leafref {
                  path "../../../../te:globals/"
                     + "te:named-admin-groups/te:named-admin-group/"
                     + "te:name";
                }
                description
                  "A named admin-group entry.";
              }
            }
          }
        }
        choice srlg-type {
          description
            "Choice of SRLG configuration.";
          case value-srlgs {
            list values {
              key "value";
              description
                "List of SRLG values that
                 this link is part of.";
              leaf value {
                type uint32 {
                  range "0..4294967295";
                }
                description
                  "Value of the SRLG";
              }
            }
          }
          case named-srlgs {
            list named-srlgs {
              if-feature "te-types:named-srlg-groups";
              key "named-srlg";
              description
                "A list of named SRLG entries.";
              leaf named-srlg {
                type leafref {
                  path "../../../../te:globals/"
                     + "te:named-srlgs/te:named-srlg/te:name";
                }
                description
                  "A named SRLG entry.";
              }
            }
          }
        }
        uses te-igp-flooding-bandwidth-config;
        list switching-capabilities {
          key "switching-capability";
          description
            "List of interface capabilities for this interface.";
          leaf switching-capability {
            type identityref {
              base te-types:switching-capabilities;
            }
            description
              "Switching Capability for this interface.";
          }
          leaf encoding {
            type identityref {
              base te-types:lsp-encoding-types;
            }
            description
              "Encoding supported by this interface.";
          }
        }
        container te-advertisements-state {
          config false;
          description
            "TE interface advertisements state container.";
          leaf flood-interval {
            type uint32;
            description
              "The periodic flooding interval.";
          }
          leaf last-flooded-time {
            type uint32;
            units "seconds";
            description
              "Time elapsed since last flooding in seconds.";
          }
          leaf next-flooded-time {
            type uint32;
            units "seconds";
            description
              "Time remained for next flooding in seconds.";
          }
          leaf last-flooded-trigger {
            type enumeration {
              enum link-up {
                description
                  "Link-up flooding trigger.";
              }
              enum link-down {
                description
                  "Link-down flooding trigger.";
              }
              enum threshold-up {
                description
                  "Bandwidth reservation up threshold.";
              }
              enum threshold-down {
                description
                  "Bandwidth reservation down threshold.";
              }
              enum bandwidth-change {
                description
                  "Bandwidth capacity change.";
              }
              enum user-initiated {
                description
                  "Initiated by user.";
              }
              enum srlg-change {
                description
                  "SRLG property change.";
              }
              enum periodic-timer {
                description
                  "Periodic timer expired.";
              }
            }
            default "periodic-timer";
            description
              "Trigger for the last flood.";
          }
          list advertised-level-areas {
            key "level-area";
            description
              "List of level-areas that the TE interface is
               advertised in.";
            leaf level-area {
              type uint32;
              description
                "The IGP area or level where the TE interface link
                 state is advertised in.";
            }
          }
        }
      }
    }
  }

  /* TE globals device augmentation */

  augment "/te:te/te:globals" {
    description
      "Global TE device specific configuration parameters.";
    uses lsp-device-timers;
  }

  /* TE tunnels device configuration augmentation */

  augment "/te:te/te:tunnels/te:tunnel" {
    description
      "Tunnel device dependent augmentation.";
    leaf path-invalidation-action {
      type identityref {
        base te-types:path-invalidation-action-type;
      }
      description
        "Tunnel path invalidation action.";
    }
    uses lsp-device-timers;
  }

  /* TE LSPs device state augmentation */

  augment "/te:te/te:lsps/te:lsp" {
    description
      "TE LSP device dependent augmentation.";
    container lsp-timers {
      when "../te:origin-type = 'ingress'" {
        description
          "Applicable to ingress LSPs only.";
      }
      description
        "Ingress LSP timers.";
      leaf uptime {
        type uint32;
        units "seconds";
        description
          "The LSP uptime.";
      }
      leaf time-to-install {
        type uint32;
        units "seconds";
        description
          "The time remaining for a new LSP to be instantiated
           in forwarding to carry traffic.";
      }
      leaf time-to-destroy {
        type uint32;
        units "seconds";
        description
          "The time remaining for a existing LSP to be deleted
           from forwarding.";
      }
    }
    container downstream-info {
      when "../te:origin-type != 'egress'" {
        description
          "Downstream information of the LSP.";
      }
      description
        "downstream information.";
      leaf nhop {
        type te-types:te-tp-id;
        description
          "downstream next-hop address.";
      }
      leaf outgoing-interface {
        type if:interface-ref;
        description
          "downstream interface.";
      }
      container neighbor {
        uses te:te-generic-node-id;
        description
          "downstream neighbor address.";
      }
      leaf label {
        type rt-types:generalized-label;
        description
          "downstream label.";
      }
    }
    container upstream-info {
      when "../te:origin-type != 'ingress'" {
        description
          "Upstream information of the LSP.";
      }
      description
        "upstream information.";
      leaf phop {
        type te-types:te-tp-id;
        description
          "upstream next-hop or previous-hop address.";
      }
      container neighbor {
        uses te:te-generic-node-id;
        description
          "upstream neighbor address.";
      }
      leaf label {
        type rt-types:generalized-label;
        description
          "upstream label.";
      }
    }
  }

  /* TE interfaces RPCs/execution Data */

  rpc link-state-update {
    description
      "Triggers a link state update for the specific interface.";
    input {
      choice filter-type {
        mandatory true;
        description
          "Filter choice.";
        case match-all {
          leaf all {
            type empty;
            mandatory true;
            description
              "Match all TE interfaces.";
          }
        }
        case match-one-interface {
          leaf interface {
            type if:interface-ref;
            description
              "Match a specific TE interface.";
          }
        }
      }
    }
  }
}

]]>




Notifications

Notifications are a key component of any topology data model.

 and  define a subscription mechanism and a push
mechanism for YANG datastores.  These mechanisms currently allow the
user to:


  Subscribe to notifications on a per-client basis.
  Specify subtree filters or XML Path Language (XPath) filters so
that only contents of interest will be sent.
  Specify either periodic or on-demand notifications.



IANA Considerations

This document registers the following URIs in the IETF XML registry
.
Following the format in , the following registrations are
requested to be made.



This document registers two YANG modules in the YANG Module Names
registry .




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
 or RESTCONF . The lowest NETCONF layer is the secure
transport layer, and the mandatory-to-implement secure transport is Secure
Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the
mandatory-to-implement secure transport is TLS .

The Network Configuration Access Control Model (NACM)  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:

"/te/globals":  This module specifies the global TE configurations on a device.
Unauthorized access to this container could cause the device to ignore packets
it should receive and process.

"/te/tunnels":  This list specifies the configuration and state of TE Tunnels
present on the device or controller.  Unauthorized access to this list could
cause the device to ignore packets it should receive and process. An attacker
may also use state to derive information about the network topology,
and subsequently orchestrate further attacks.

"/te/interfaces":  This list specifies the configuration and state TE interfaces
on a device. Unauthorized access to this list could cause the device to ignore packets it
should receive and process.

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:

"/te/lsps": this list contains information state about established LSPs in the network.
An attacker can use this information to derive information about the network topology,
and subsequently orchestrate further attacks.

Some of the RPC operations in this YANG module may be considered sensitive or
vulnerable in some network environments. It is thus important to control access
to these operations. These are the operations and their
sensitivity/vulnerability:

"/te/tunnels-actions": using this RPC, an attacker can modify existing paths that
may be carrying live traffic, and hence result to interruption to services
carried over the network.

"/te/tunnels-path-compute": using this RPC, an attacker can retrieve secured
information about the network provider which can be used to orchestrate further
attacks.

The security considerations spelled out in the YANG 1.1 specification
 apply for this document as well.


Acknowledgement

The authors would like to thank the  members of the multi-vendor YANG design
team who are involved in the definition of this model.

The authors would like to thank Tom Petch and Adrian Farrel for reviewing and
providing useful feedback about the document. The authors would also like to
thank Loa Andersson, Lou Berger, Sergio Belotti, Italo Busi, Carlo Perocchio,
Francesco Lazzeri, Aihua Guo, Dhruv Dhody, and Raqib Jones for providing
feedback on this document.


Contributors




Appendix A: Data Tree Examples

This section contains examples of use of the model with RESTCONF  and JSON encoding.

For the example we will use a 4 node MPLS network were RSVP-TE MPLS Tunnels can be setup. The
loopbacks of each router are shown. The network in  will be used in the examples
described in the following sections.



Basic Tunnel Setup

This example uses the TE Tunnel YANG data model defined in this document to create an
RSVP-TE signaled Tunnel of packet LSP encoding type. First, the TE Tunnel is created with no specific restrictions or constraints (e.g., protection or restoration).
The TE Tunnel ingresses on router A and egresses on router D.

In this case, the TE Tunnel is created without specifying additional information about the primary paths.




Global Named Path Constraints

This example uses the YANG data model to create a 'named path constraint' that can be reference by TE Tunnels.
The path constraint, in this case, limits the TE Tunnel hops for the computed path.




Tunnel with Global Path Constraint

In this example, the previously created 'named path constraint' is applied to the TE Tunnel created in .




Tunnel with Per-tunnel Path Constraint

In this example, the a per tunnel path constraint is explicitly indicated under the TE Tunnel created in  to constrain the computed path for the tunnel.




Tunnel State

In this example, the 'GET' query is sent to return the state stored about the tunnel.



The request, with status code 200 would include, for example, the following json:




Example TE Tunnel with Primary and Secondary Paths



Below is the state retrieved for a TE tunnel from source 192.0.2.1 to 192.0.2.5
with primary, secondary, reverse, and secondary reverse paths as shown in .





Appendix B: Full Model Tree Diagram

 shows the full tree diagram of the TE YANG model defined in
module 'ietf-te.yang'.

 /te/lsps/lsp/tunnel-name
          +--ro node?          leafref
          +--ro lsp-id?        leafref
  grouping path-computation-response:
    +--ro computed-paths-properties
    |  +--ro computed-path-properties* [k-index]
    |     +--ro k-index?                            uint8
    |     +---u te-types:generic-path-properties
    +--ro computed-path-error-infos
       +--ro computed-path-error-info* []
          +--ro error-description?   string
          +--ro error-timestamp?     yang:date-and-time
          +--ro error-reason?        identityref
  grouping protection-restoration-properties:
    +-- protection
    |  +-- protection-type?                identityref
    |  +-- protection-reversion-disable?   boolean
    |  +-- hold-off-time?                  uint32
    |  +-- wait-to-revert?                 uint16
    |  +-- aps-signal-id?                  uint8
    +-- restoration
       +-- restoration-type?                identityref
       +-- restoration-scheme?              identityref
       +-- restoration-reversion-disable?   boolean
       +-- hold-off-time?                   uint32
       +-- wait-to-restore?                 uint16
       +-- wait-to-revert?                  uint16
  grouping tunnel-associations-properties:
    +-- association-objects
       +-- association-object* [association-key]
       |  +-- association-key?   string
       |  +-- type?              identityref
       |  +-- id?                uint16
       |  +-- source
       |     +---u te-generic-node-id
       +-- association-object-extended* [association-key]
          +-- association-key?   string
          +-- type?              identityref
          +-- id?                uint16
          +-- source
          |  +---u te-generic-node-id
          +-- global-source?     uint32
          +-- extended-id?       yang:hex-string
  grouping tunnel-common-attributes:
    +-- source?             te-types:te-node-id
    +-- destination?        te-types:te-node-id
    +-- src-tunnel-tp-id?   binary
    +-- dst-tunnel-tp-id?   binary
    +-- bidirectional?      boolean
  grouping tunnel-hierarchy-properties:
    +-- hierarchy
       +-- dependency-tunnels
       |  +-- dependency-tunnel* [name]
       |     +-- name?
       |     |       -> /te/tunnels/tunnel/name
       |     +---u te-types:encoding-and-switching-type
       +-- hierarchical-link
          +-- enable?                            boolean
          +-- local-te-node-id?                  te-types:te-node-id
          +-- local-te-link-tp-id?               te-types:te-tp-id
          +-- remote-te-node-id?                 te-types:te-node-id
          +---u te-types:te-topology-identifier
  grouping path-constraints-common:
    +---u te-types:common-path-constraints-attributes
    +---u te-types:generic-path-disjointness
    +---u te-types:path-constraints-route-objects
    +-- path-in-segment!
    |  +---u te-types:label-set-info
    +-- path-out-segment!
       +---u te-types:label-set-info
]]>