ogondio-nmop-isis-topology-00.txt

Internet DRAFT - draft-ogondio-nmop-isis-topology

draft-ogondio-nmop-isis-topology

Last Version:	draft-ogondio-nmop-isis-topology-00.txt	Tracker Entry
Date:	`04-Mar-2024`
Disposition:	current

nmop O. G. D. Dios
Internet-Draft Telefonica
Intended status: Standards Track S. B. Giraldo
Expires: 5 September 2024 V. Lopez
Nokia
D. Ceccarelli
Cisco
B. Claise
Huawei
4 March 2024

A YANG Data Model for Intermediate System to intermediate System (IS-IS)
Topology
draft-ogondio-nmop-isis-topology-00

Abstract

This document defines a YANG data model for representing an
abstracted view of a network topology that contains Intermediate
System to Intermediate System (IS-IS). This document augments the
'ietf-network' data model by adding IS-IS concepts and explains how
the data model can be used to represent the IS-IS topology.

The YANG data model defined in this document conforms to the Network
Management Datastore Architecture (NMDA).

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 5 September 2024.

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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology and Notations . . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.3. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 4
1.4. Prefix in Data Node Names . . . . . . . . . . . . . . . . 4
2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Relationship with the IS-IS YANG Model . . . . . . . . . 5
2.2. Relationship with Digital Map . . . . . . . . . . . . . . 5
3. Use of IETF-Topology for Representing an IP/MPLS network
domain . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. YANG Data Model for IS-IS Topology . . . . . . . . . . . . . 7
5. RFC8345 Limitations for the IS-IS Modeling . . . . . . . . . 8
6. IS-IS Topology Tree Diagram . . . . . . . . . . . . . . . . . 9
7. YANG Model for IS-IS topology . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . 17
Appendix A. Implementation Status . . . . . . . . . . . . . . . 17
A.1. Implementation Status in Telefonica Group . . . . . . . . 18
A.2. Huawei Digital Map PoC Status . . . . . . . . . . . . . . 18
A.3. Implementation Status in E-lighthouse Network
Solutions . . . . . . . . . . . . . . . . . . . . . . . . 18
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 18
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19

1. Introduction

Network operators perform the capacity planning for their networks
and run regular what-if scenarios analysis based on representations
of the real network. Those what-if analysis and capacity planning
processes require, among other information, a topological view
(domains, nodes, links, network interconnection) of the deployed
network.

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This document defines a YANG data model representing an abstracted
view of a network topology containing Intermediate System to
Intermediate System (IS-IS). It covers the topology of IP/MPLS
networks running IS-IS as Interior Gateway Protocol (IGP) protocol.
The proposed YANG model augments the "A YANG Data Model for Network
Topologies" [RFC8345] and "A YANG Data Model for Layer 3 Topologies"
[RFC8346] by adding IS-IS concepts. It is worth to highlight that
the Yang model can also be used together with [RFC8795] and
[I-D.draft-ietf-teas-yang-l3-te-topo] when Traffic engineering
characteristics are required in the topological view.

This YANG data model can be used to export the IS-IS related topology
directly from a network controller to Operation Support System (OSS)
tools or to a higher level controller.

Note that the YANG model is in this document strictly adheres to the
concepts (and the YANG module) in "A YANG Data Model for Network
Topologies" [RFC8345] and"A YANG Data Model for Layer 3 Topologies"
[RFC8346]. While investigating the IS-IS topology, some limitations
have discovered in [RFC8345], regarding how the digital map can be
represented. Those limitations (and potential improvements) are
covered in [I-D.draft-havel-opsawg-digital-map].

This document explains the scope and purpose of the IS-IS topology
model and how the topology and service models fit together. The YANG
data model defined in this document conforms to the Network
Management Datastore Architecture [RFC8342].

1.1. Terminology and Notations

This document assumes that the reader is familiar with IS-IS and the
contents of [RFC8345]. The document uses terms from those documents.

The terminology for describing YANG data models is found in
[RFC7950], [RFC8795] and [RFC8346].

The term Digital Twin, Digital Map, Digital Map Modelling, Digital
Map Model, Digital Map Data, and Topology are specified in
[I-D.draft-havel-opsawg-digital-map].

1.2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119], [RFC8174] when, and only when, they appear in all
capitals, as shown here.

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1.3. Tree Diagram

Authors include a simplified graphical representation of the data
model specified in Section 5 of this document. The meaning of the
symbols in these diagrams is defined in [RFC8340].

1.4. Prefix 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 the following table.

Table 1: Prefixes and corresponding YANG
modules

RFC Editor Note: Please replace XXXX with the RFC number assigned to
this document. Please remove this note.

2. Use Cases

This information is required in the IP/MPLS planning process to
properly assess the required network resources to meet the traffic
demands in normal and failure scenarios. Network operators perform
the capacity planning for their networks and run regular what-if
scenarios analysis based on representations of the real network.
Those what-if analysis and capacity planning processes require, among
other information, a topological view (domains, nodes, links, network
interconnection) of the deployed network.

The standardization of an abstracted view of the IS-IS topology model
as NorthBound Interface (NBI) of Software Defined Networking (SDN)
controllers allows the unified query of the IS-IS topology in order
to inject this information into third party tools covering
specialized cases.

The IS-IS topological model should export enough IS-IS information to
permit these tools to simulate the IP routing. By mapping the
traffic demand, ideally at the IP flow level, to the topology, we can
simulate the traffic growth, evaluating this way its effect on the
routing and quality of service. That is, simulating how IP-level

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traffic demands would be forwarded, after IS-IS convergence is
reached, and from there estimating, using appropriate mathematical
models, related KPIs like the occupation in the links or end-to-end
latencies.

In summary, the network-wide view of the IS-IS topology enables
multiple use cases:

* Network design: verifying that the actual deployed IS-IS network
conforms to the planned design.

* Capacity planning. Dimensioning or redesign of the IP
infrastructure to satisfy target KPI metrics under existing or
forecasted traffic demands.

* What-if analysis. Estimation of the network KPIs in modified
network situations. For instance, failure situations, traffic
anomaly situations, addition or deletion of new adjacencies, IGP
weight reconfigurations, etc.

* Failure analysis. Systematic and massive test of the network
under multiple simulated failure situations, evaluating the
network fault tolerance properties, and using mathematical models
to derive statistical network availability metrics.

2.1. Relationship with the IS-IS YANG Model

[RFC9130] specifies a YANG data model that can be used to configure
and manage the IS-IS protocol on network elements. This data model
covers the configuration of an IS-IS routing protocol instance, as
well as the retrieval of IS-IS operational states. [RFC9130] is
still expected to be used for individual network elements
configuration and monitoring. On the other hand, the proposed YANG
model in this document covers the abstracted view of the entire
network topology containing IS-IS. As such, this model is aimed at
being available via the NBI of an SDN controller.

2.2. Relationship with Digital Map

As described in [I-D.draft-havel-opsawg-digital-map], the Digital Map
provides the core multi-layer topology model and data for the digital
twin and connects them to the other digital twin models and data.

The Digital Map Modelling defines the core topological entities,
their role in the network, core properties, and relationships both
inside each layer and between the layers.

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The Digital Map Model is a basic topological model that is linked to
other functional parts of the digital twin and connects them all:
configuration, maintenance, assurance (KPIs, status, health,
symptoms), Traffic Engineering (TE), different behaviors and actions,
simulation, emulation, mathematical abstractions, AI algorithms, etc.

As such the IGP topology of the Digital Map (in this case, IS-IS) is
just one of the layers of the Digital Map, for specific user (the
network operator in charge of the IGP) for specific IGP use cases as
described before.

3. Use of IETF-Topology for Representing an IP/MPLS network domain

IP/MPLS networks can contain multiple domain IGP domains. We can
define an IGP domain as the collection of nodes and links that
participate in the same IGP process. The topology information of a
domain can be structured according to ietf-network-topology data
model [RFC8345]. For example, if BGP-LS [RFC9552] is used to collect
the information, the nodes and links that are announced with the same
combination of AS number / domain ID are considered to belong to the
same domain.

If a node and/or layer termination point participates in more than
one IGP, it will be present in multiple IGP domain networks. As the
basic components, node/links/termination points [RFC8345], it is
therefore possible to joint the different different IGP topologies
from a digital map modeling point of view. The ietf-network instance
MUST include the following properties to indicate it is a domain
running an IGP instance:

A network-id that uniquely identifies such domain in the network.
The "network-types" property should include the l3t:l3-unicast-
topology, to indicate it is a network in which the nodes are capable
of forwarding unicast packet. Also, this draft proposed to add a new
property, "isis-topology", to indicate the topology being represented
is running the IS-IS IGP process.

Also, should the topology include information such as bandwidth,
delay information or color, it must include the "YANG Data Model for
Traffic Engineering" [RFC8795] te-topology YANG data model. To
include delay and bandwdith performance measurements , MUST include
tet-pkt:te-packet under the previous property The supporting-network
property can include the network-id of a base layer-3 network. The
node property should include the list of nodes as described below.
The ietf-network-topology:link MUST be present, with one link per
each IP adjacency (one link for each direction of the adjancency).

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4. YANG Data Model for IS-IS Topology

The abstract (base) network data model is defined in the "ietf-
network" and "ietf-network-topology" modules of [RFC8345]. The L3
topology module is defined in the "ietf-l3-unicast-topology" module
of [RFC8346]. The ietf-l3-isis-topology builds on the data models
defined in [RFC8345] and [RFC8346], augmenting the nodes with IS-IS
information.

There is a set of parameters and augmentations that are included at
the node level. Each parameter and description are detailed
following:

* Network-types: Its presence identifies the IS-IS topology type.
Thus, the network type MUST be isis-topology.

* IS-IS timer attributes: Identifies the node timer attributes
configured in the network element. They are LSP lifetime and the
LSP refresh interval.

* IS-IS status: contains the IS-IS status attributes (level, area-
address and neighbours).

The following figure is based on the Figure 1 from [RFC8346], where
the example-ospf-topology is replaced with ietf-l3-isis-topology and
where arrows show how the modules augment each other.

+-----------------------------+
| +-----------------------+ |
| | ietf-network | |
| +----------^------------+ |
| | |
| +-----------------------+ |
| | ietf-network-topology | |
| +----------+------------+ |
+-------------^---------------+
|
|
+------------^-------------+
| ietf-l3-unicast-topology |
+------------^-------------+
|
|
+-----------^-----------+
| ietf-l3-isis-topology |
+-----------------------+

Figure 1: IS-IS Topology module structure

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There is a set of parameters and augmentations that are included at
the network level.

* Network-types: Its presence identifies the IS-IS topology type.
Thus, the network type MUST be isis-topology.

There is a set of parameters and augmentations that are included at
the node level. Each parameter and description are detailed
following:

* IS-IS node core attributes: contains the IS-IS core attributes
(system-id, level, area-address).

* IS-IS timer attributes: Identifies the node timer attributes
configured in the network element. They are LSP lifetime and the
LSP refresh interval.

There is a set of parameters and augmentations that are included at
the link level. Each parameter and description are detailed
following:

* IS-IS link level. The level must be the same as the termination
points at each end for Level 1 and Level 2 interfaces. There may
be 2 links between the Level1-2 IS-IS interfaces, one for Level 1
adjacency and one for Level 2 adjacency.

* IS-IS link metric. Added on top of metric1 and metric2 of the l3-
link-attributes

There is a set of parameters and augmentations are included at the
termination point level. Each parameter is listed as follows:

* Interface-type: point-to point or broadcast

* Level. The level must be the same as for the node, except when
node is Level 1-2 and the interfaces can only be Level 1 or Level
2.

* Passive mode

5. RFC8345 Limitations for the IS-IS Modeling

There are some limitations in the [RFC8345] that are explained in
more detail in [I-D.draft-havel-opsawg-digital-map]. The current
version of the ietf-l3-isis-topology module is based on the current
version of [RFC8345]. The following will be addressed when [RFC8345]
is extended to support the identified limitations:

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* Both IS-IS domain and IS-IS areas could be modelled as networks

* The IS-IS Areas will be connected via IS-IS links

* IS-IS nodes could belong to multiple IS-IS networks

6. IS-IS Topology Tree Diagram

Figure 2 below shows the tree diagram of the YANG data model defined
in module ietf-l3-isis-topology.yang (Figure 3).

module: ietf-l3-isis-topology

augment /nw:networks/nw:network/nw:network-types:
+--rw isis-topology!
augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes:
+--rw isis-timer-attributes
| +--rw lsp-mtu? uint16
| +--rw lsp-lifetime? uint16
| +--rw lsp-refresh? rt-types:timer-value-seconds16 {lsp-refresh}?
| +--rw poi-tlv? boolean {poi-tlv}?
+--rw isis-node-attributes
+--rw system-id? ietf-isis:system-id
+--rw level? ietf-isis:level
+--rw area-address* ietf-isis:area-address
+--rw lsp-lifetime? uint16
+--rw lsp-refresh-interval? uint16
augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes:
+--rw isis-link-attributes
+--rw metric? uint32
+--rw level? ietf-isis:level
augment /nw:networks/nw:network/nw:node/nt:termination-point/l3t:l3-termination-point-attributes:
+--rw isis-termination-point-attributes
+--rw interface-type? ietf-isis:interface-type
+--rw level? ietf-isis:level
+--rw is-passive? boolean

Figure 2: IS-IS Topology tree diagram

7. YANG Model for IS-IS topology

This module imports types from [RFC8343] and [RFC8345]. Following
the YANG model is presented.

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<CODE BEGINS> file "ietf-l3-isis-topology@2023-10-23.yang"
module ietf-l3-isis-topology {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-l3-isis-topology";
prefix "isisnt";

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-isis {
prefix "ietf-isis";
reference
"RFC 9130: YANG Data Model for the IS-IS Protocols";
}

organization
"IETF NMOP (Network Management Operations) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/opsawg/>
WG List: <mailto:opsawg@ietf.org>

Editor: Oscar Gonzalez de Dios
<mailto:oscar.gonzalezdedios@telefonica.com>
Editor: Samier Barguil
<mailto:samier.barguil_giraldo@nokia.com>
Editor: Victor Lopez
<mailto:victor.lopez@nokia.com>
Editor: Benoit Claise
<mailto:benoit.claise@huwaei.com>";
description
"This module defines a model for Layer 3 ISIS

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topologies.

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.";

revision 2022-09-21 {
description
"Initial version";
reference
"RFC XXXX: A YANG Data Model for Intermediate System to
Intermediate System (ISIS) Topology";
}

grouping isis-topology-type {
description "Identifies the topology type to be ISIS.";
container isis-topology {
presence "indicates ISIS topology";
description
"The presence of the container node indicates ISIS
topology";
}
}

grouping isis-link-attributes {
description "Identifies the IS-IS link attributes.";
container isis-link-attributes {
description
"Main Container to identify the ISIS Link Attributes";
leaf metric {
type uint32 {
range "0 .. 16777215";
}
description
"This type defines wide style format of IS-IS metric.";
}
leaf level {
type ietf-isis:level;

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description
"Level of an IS-IS node - can be level-1,
level-2 or level-all.";
}
}
}

grouping isis-node-attributes {
description "isis node scope attributes";
container isis-timer-attributes {
description
"Contains node timer attributes";
uses ietf-isis:lsp-parameters;
}
container isis-node-attributes {
description
"Main Container to identify the ISIS Node Attributes";
leaf system-id {
type ietf-isis:system-id;
description
"System-id of the node.";
}
leaf level {
type ietf-isis:level;
description
"Level of an IS-IS node - can be level-1,
level-2 or level-all.";
}
leaf-list area-address {
type ietf-isis:area-address;
description
"List of areas supported by the protocol instance.";
}
leaf lsp-lifetime {
type uint16 {
range "1..65535";
}
units "seconds";
description
"Lifetime of the router's LSPs in seconds.";
}
leaf lsp-refresh-interval {
type uint16 {
range "1..65535";
}
units "seconds";
description
"Refresh interval of the router's LSPs in seconds.";

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}
}
}

grouping isis-termination-point-attributes {
description "IS-IS termination point scope attributes";
container isis-termination-point-attributes {
description
"Indicates the termination point from the
which the IS-IS is configured. A termination
point can be a physical port, an interface, etc.";

leaf interface-type {
type ietf-isis:interface-type;
description
"Type of adjacency (broadcast or point-to-point) to be established
for the interface.
This dictates the type of hello messages that are used.";
}

leaf level {
type ietf-isis:level;
description
"Level of an IS-IS node - can be level-1,
level-2 or level-all.";
}

leaf is-passive{
type boolean;
description
"Indicates whether the interface is in passive mode (IS-IS
not running but network is advertised).";
}
}
}

augment "/nw:networks/nw:network/nw:network-types" {
description
"Introduces new network type for L3 Unicast topology";
uses isis-topology-type;
}

augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes" {
when "/nw:networks/nw:network/nw:network-types/isisnt:isis-topology" {
description
"Augmentation parameters apply only for networks with
isis topology";
}

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description
"isis node-level attributes ";
uses isis-node-attributes;
}

augment "/nw:networks/nw:network/nt:link/l3t:l3-link-attributes" {
when "/nw:networks/nw:network/nw:network-types/isisnt:isis-topology" {
description
"Augmentation parameters apply only for networks with
IS-IS topology";
}
description
"Augments topology link configuration";
uses isis-link-attributes;
}

augment "/nw:networks/nw:network/nw:node/nt:termination-point"+
"/l3t:l3-termination-point-attributes" {
when "/nw:networks/nw:network/nw:network-types/isisnt:isis-topology" {
description
"Augmentation parameters apply only for networks with
IS-IS topology";
}
description
"Augments topology termination point configuration";
uses isis-termination-point-attributes;
}
}
<CODE ENDS>

Figure 3: IS-IS Topology YANG module

8. 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.

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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.

9. IANA Considerations

This document registers the following namespace URIs in the IETF XML
registry [RFC3688]:

--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-l3-isis-topology
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
--------------------------------------------------------------------

This document registers the following YANG module in the YANG Module
Names registry [RFC6020]:

--------------------------------------------------------------------
name: ietf-l3-isis-topology
namespace: urn:ietf:params:xml:ns:yang:ietf-l3-isis-topology
maintained by IANA: N
prefix: ietf-l3-isis-topology
reference: RFC XXXX
--------------------------------------------------------------------

10. References

10.1. Normative References

[I-D.draft-havel-opsawg-digital-map]
Havel, O., Claise, B., de Dios, O. G., Elhassany, A.,
Graf, T., and M. Boucadair, "Modeling the Digital Map
based on RFC 8345: Sharing Experience and Perspectives",
Work in Progress, Internet-Draft, draft-havel-opsawg-
digital-map-01, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-havel-opsawg-
digital-map-01>.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.

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[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/rfc/rfc3688>.

[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/rfc/rfc6020>.

[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/rfc/rfc6242>.

[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/rfc/rfc6991>.

[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/rfc/rfc7950>.

[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/rfc/rfc8040>.

[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/rfc/rfc8340>.

[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/rfc/rfc8341>.

[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,
<https://www.rfc-editor.org/rfc/rfc8342>.

[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/rfc/rfc8343>.

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[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, <https://www.rfc-editor.org/rfc/rfc8345>.

[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, <https://www.rfc-editor.org/rfc/rfc8346>.

[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>.

[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,
<https://www.rfc-editor.org/rfc/rfc8795>.

[RFC9130] Litkowski, S., Ed., Yeung, D., Lindem, A., Zhang, J., and
L. Lhotka, "YANG Data Model for the IS-IS Protocol",
RFC 9130, DOI 10.17487/RFC9130, October 2022,
<https://www.rfc-editor.org/rfc/rfc9130>.

10.2. Informative References

[I-D.draft-ietf-teas-yang-l3-te-topo]
Liu, X., Bryskin, I., Beeram, V. P., Saad, T., Shah, H.
C., and O. G. de Dios, "YANG Data Model for Layer 3 TE
Topologies", Work in Progress, Internet-Draft, draft-ietf-
teas-yang-l3-te-topo-16, 2 March 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
yang-l3-te-topo-16>.

[RFC9552] Talaulikar, K., Ed., "Distribution of Link-State and
Traffic Engineering Information Using BGP", RFC 9552,
DOI 10.17487/RFC9552, December 2023,
<https://www.rfc-editor.org/rfc/rfc9552>.

Appendix A. Implementation Status

Note to the RFC-Editor: Please remove this section before publishing.

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A.1. Implementation Status in Telefonica Group

The Yang based topology model proposed in this draft is being used
today in one of the Telefonica operations to export the Multi-vendor
IP/MPLS topology based on multiple IS-IS domains to several Operation
Support System tools for visualization, capacity planning and
simulation. A commercial controller has implemented the exposure of
the information. It is one of the building blocks to expose the
network capabilities, together with other models which cover the
inventory and service provisioning in a vendor-agnostic fashion.

A.2. Huawei Digital Map PoC Status

As mentioned in [I-D.draft-havel-opsawg-digital-map], a Digital Map
PoC with a real lab has been built, based on multi- vendor devices,
with [RFC8345] as the base YANG module for the topology building
blocks. This PoC successfully modelled IS-IS routing (among other
technologies and layers), but it needs to be further aligned with
this latest developments in this draft.

A.3. Implementation Status in E-lighthouse Network Solutions

E-lighthouse Network Solutions (https://e-lighthouse.com/)
implementation is consuming the IS-IS network topology information
exported by a commercial controller, using the Yang model proposed in
this draft. It is able to simulate the network behavior under
different changes, covering the what-if, failure analysis,
dimensioning and other use cases mentioned in this draft.

Acknowledgments

The authors would like to thank Pierre Francois for the review and
suggestions the document.

This work is partially supported by the European Commission under
grant agreement No. 101092766 (ALLEGRO Project) and Horizon 2020
Secured autonomic traffic management for a Tera of SDN flows
(Teraflow) project (grant agreement number 101015857).

Contributors

Olga Havel
Huawei
Email: olga.havel@huawei.com

Pablo Pavon
Universidad Politecnica de Cartegena

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Email: pablo.pavon@upct.es

Authors' Addresses

Oscar González de Dios
Telefonica
Email: oscar.gonzalezdedios@telefonica.com

Samier Barguil Giraldo
Nokia
Email: samier.barguil_giraldo@nokia.com

Victor Lopez
Nokia
Email: victor.lopez@nokia.com

Daniele Ceccarelli
Cisco
Email: dceccare@cisco.com

Benoit Claise
Huawei
Email: benoit.claise@huawei.com

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