Internet DRAFT - draft-havel-nmop-digital-map
draft-havel-nmop-digital-map
NMOP O. Havel
Internet-Draft B. Claise
Intended status: Informational Huawei
Expires: 4 September 2024 O. G. D. Dios
Telefonica
A. Elhassany
T. Graf
Swisscom
M. Boucadair
Orange
3 March 2024
Modeling the Digital Map based on RFC 8345: Sharing Experience and
Perspectives
draft-havel-nmop-digital-map-00
Abstract
This document shares experience in modelling Digital Map based on the
IETF RFC 8345 topology YANG modules and some of its augmentations.
First, the concept of Digital Map is defined and its connection to
the Digital Twin is explained. Next to Digital Map requirements and
use cases, the document identifies a set of open issues encountered
during the modelling phases, the missing features in RFC 8345, and
some perspectives on how to address them.
Discussion Venues
This note is to be removed before publishing as an RFC.
Source for this draft and an issue tracker can be found at
https://github.com/OlgaHuawei.
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
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and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
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This Internet-Draft will expire on 4 September 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Digital Map and Digital Twin Relationship . . . . . . . . . . 6
2.1. Digital Twin . . . . . . . . . . . . . . . . . . . . . . 6
2.2. Digital Map . . . . . . . . . . . . . . . . . . . . . . . 7
2.3. Digital Map as a Prerequisite for Digital Twin . . . . . 7
3. The IETF Network Topology Approaches . . . . . . . . . . . . 8
3.1. IETF Network Topology . . . . . . . . . . . . . . . . . . 9
3.2. IETF Network Topology TE . . . . . . . . . . . . . . . . 9
4. Digital Map Requirements . . . . . . . . . . . . . . . . . . 10
4.1. Why RFC8345 is a Good Approach for Digital Map
Modelling . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. Design Requirements . . . . . . . . . . . . . . . . . . . 12
5. Digital Map Modelling Experience . . . . . . . . . . . . . . 13
5.1. What Is Not in The Base Model? . . . . . . . . . . . . . 13
5.1.1. Bidirectional Links . . . . . . . . . . . . . . . . . 13
5.1.2. Multipoint Connectivity . . . . . . . . . . . . . . . 14
5.1.3. Links Between Networks . . . . . . . . . . . . . . . 16
5.1.4. Networks Part of Other Networks . . . . . . . . . . . 17
5.1.5. Nodes, tps and links in multiple networks . . . . . . 18
5.1.6. Missing Supporting Relationships . . . . . . . . . . 19
5.1.7. Missing Topology Semantics . . . . . . . . . . . . . 19
5.2. Open Issues (for Further Analysis or Resolved) . . . . . 20
6. Digital Map Modeling Guidelines . . . . . . . . . . . . . . . 21
6.1. Guidelines for Generic Digital Map Extensions . . . . . . 21
6.2. Guidelines for New Technologies/Layers Extensions . . . . 23
6.3. Guidelines for Digital Maps Connectiont to Other
Components . . . . . . . . . . . . . . . . . . . . . . . 24
6.3.1. How to connect YANG models with other modelling
mechanisms . . . . . . . . . . . . . . . . . . . . . 24
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6.4. Digital Map APIs . . . . . . . . . . . . . . . . . . . . 24
6.5. Digital Map Knowledge . . . . . . . . . . . . . . . . . . 24
7. Related IETF Activities . . . . . . . . . . . . . . . . . . . 25
7.1. Network Topology . . . . . . . . . . . . . . . . . . . . 25
7.2. Core Digital Map Components . . . . . . . . . . . . . . . 26
7.3. Additional Digital Map Components . . . . . . . . . . . . 26
7.4. Network Inventory (IVY) Proposed Working . . . . . . . . 27
8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 28
9. Security Considerations . . . . . . . . . . . . . . . . . . . 29
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
11.1. Normative References . . . . . . . . . . . . . . . . . . 29
11.2. Informative References . . . . . . . . . . . . . . . . . 30
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 34
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34
1. Introduction
[RFC8345] specifies a topology YANG model with many YANG
augmentations for different technologies and service types.
The modelling approach based upon [RFC8345] provides a standard IETF
based API.
At the time of writing (2024), there are at least 59 YANG modules
that are augmenting [RFC8345]; 58 IETF-authored modules and 1 BBF-
authored module. 14 of these modules have maturity level of
'ratified', 17 of them have maturity level of 'adopted', 31 modules
have maturity level of 'latest-approved', and 27 of these modules
have maturity level of 'initial'.
The up-to-date information can be found in the YANG Catalog
[Catalog].
From the set of IETF RFCs and I-Ds (at different level of maturity),
we designed a Digital Map Proof of concept (PoC), with the following
objectives and functionalities:
* Can the central RFC 8345 YANG module be a good basis to model a
Digital Map?
* How the different topology related IETF YANG modules fit (or not)
together?
* Modelling of Digital Map entities, relationships, and rules how to
build aggregated entities and relationships. Does the base model
support key requirements that emerge for a specific layer?
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* Modelling multiple underlay/overlay layers from Layer 2 to Layer 3
to customer service layer. To what extent it is easy to augment
the base model to support new technologies?
* Can the base model be augmented for any new layer and
technologies?
This memo documents an experience in the modeling aspects of the
Digital Map, based on a PoC implementation, basically documenting the
effort and the open issues encountered so far. During the PoC, we
also identified a set of requirements and verified the PoC approach
by demoing it iteratively.
Practically, we developed a PoC with a real lab, based on multi-
vendor devices, with [RFC8345] as the base YANG module.
The PoC successfully modelled the following:
* Layer 2 network topology (used [RFC8944])
* Layer 3 network topology (used [RFC8346])
* OSPF routing topology (aligned with
[I-D.ogondio-opsawg-ospf-topology])
* IS-IS routing topology (aligned with
[I-D.ogondio-opsawg-isis-topology])
* BGP routing topology
* MPLS LDP
* MPLS Traffic Engineering (TE) tunnels
* SRv6 tunnels
* L3VPN service
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The document uses the following terms
Digital Twin: Virtual instance of a physical system (twin) that is
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continually updated with the latter's performance, maintenance and
health status data throughout the physical system's life cycle (as
defined in Section 2.2 of
[I-D.irtf-nmrg-network-digital-twin-arch]
Topology: Network topology defines how physical or logical nodes,
links and interfaces are related and arranges. Service topology
defines how service components (e.g., VPN instances, customer
interfaces, and customer links) between customer sites are
interrelated and arranged. There are at least 8 types of
topologies: point to point, bus, ring, star, tree, mesh, hybrid
and daisy chain. Topologies may be unidirectional or
bidirectional (bus, some rings).
Topology layer: Defines a layer in the multilayer topology. A
multilayer topology models relationships between different layers
of connectivity, where each layer represents a connectivity aspect
of the network and service that needs to be configured, controlled
and monitored.
The layer can also represent what needs to be managed by a
specific user, for example IGP layer can be of interest to the
user troubleshooting the routing, while the optical layer may be
of interest to the user managing the optical network.
Some topology layers may relate closely to OSI layers, like L1
topology for physical topology, Layer 2 for link topology and
Layer 3 for IPv4 and IPv6 topologies.
Some topology layers represent the control aspects of Layer 3,
like OSPF, IS-IS, or BGP.
The top layer represents the service view of the connectivity,
that can differ for different types of services and for different
providers/solutions.
Digital Map: Basis for the Digital Twin that provides a virtual
instance of the topological information of the network. It
provides the core multi-layer topology model and data for the
Digital Twin and connects them to the other Digital Twin models
and data.
Digital Map modelling: The set of principles, guidelines, and
conventions to model the Digital Map using the IETF [RFC8345]
approach. They cover the network types (layers and sublayers),
entity types, entity roles (network, node, termination point or
link), entity properties and relationship types between entities.
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Digital Map model: Defines the core topological entities, their role
in the network, core properties and relationships both inside each
layer and between the layers.
It is the 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, etc.), traffic engineering, different behaviors,
simulation, emulation, mathematical abstractions, AI algorithms,
etc.
Digital Map data: Consists of instances of network and service
topologies at different layers. This includes instances of
networks, nodes, links and termination points, topological
relationships between nodes, links and termination points inside a
network, relationships between instances belonging to different
networks, links to functional data for the instances, including
configuration, health, symptoms.
:The data can be historical, real-time, or future data for 'what-
if' scenarios.
2. Digital Map and Digital Twin Relationship
2.1. Digital Twin
The network digital twin (referred to simply as Digital Twin)
concepts and a reference architecture are proposed in the "Digital
Twin Network: Concepts and Reference Architecture"
[I-D.irtf-nmrg-network-digital-twin-arch]. That reference document
defines the core elements of Digital Twin: Data, Models, Interfaces,
and Mapping.
The Digital Twin, constructed based on the four core technology
elements, is intended to analyze, diagnose, emulate, and control the
physical network in its whole lifecycle with the help of optimization
algorithms, management methods, and expert knowledge.
Also, that document states that a Digital Twin can be seen as an
indispensable part of the overall network system and provides a
general architecture involving the whole lifecycle of physical
networks in the future, serving the application of innovative network
technologies (e.g., network planning, construction, maintenance and
optimization, improving the automation and intelligence level of the
network).
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2.2. Digital Map
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
(network, node, link, and interface), their role in the network, core
properties, and relationships both inside each layer and between the
layers.
The Digital Map model can be approached as a 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.
The Digital Map data consists of virtual instances of network and
service topologies at different layers.
The Digital Map provides the access to this data via standard APIs
for both read and write operations (write operations for offline
simulations), with query capabilities and links to other YANG modules
(e.g., Service Assurance for Intent-based Networking (SAIN)
[RFC9417], Service Attachement Points (SAPs) [RFC9408], Inventory
[I-D.ietf-ivy-network-inventory-yang], and Assets
[I-D.palmero-opsawg-dmlmo]) and non-YANG models.
2.3. Digital Map as a Prerequisite for Digital Twin
One of the important requirements for Digital Twin is to ease
correlating all models and data to topological entities at different
layers in the layered twin network. The Digital Map aims to provide
a virtual instance of the topological information of the network,
based on this Digital Map Model. *Building a Digital Map is
prerequisite towards the Digital Twin.*
The Digital Map model/data provide this missing correlation between
the topology models/data and all other models/data: KPIs, alarms,
incidents, inventory (with UUIDs), configuration, traffic
engineering, planning, simulation ("what-if"), emulations, actions,
and behaviors.
Some of these models/data provide a device view, some provide a
network or subnetwork view, while others focus more on the customer
service perspective. All these views are needed for both inner and
outer closed-loops.
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It is debatable what is part of the Digital Map itself versus what
are pointers from the Digital Map to some other sources of
information. As an example, a Digital Map should not specifically
include all information about the device inventory (product name,
vendor, product series, embedded software, and hardware/software
versions, as specified in Network Inventory (IVY) WG, for example. A
pointer to another inventory system might be sufficient or support of
means that ease the mapping between inventory and topology.
Similarly, Digital Map should not specifically contain incidents,
configuration, data plane monitoring, or even assurance information,
simply to name a few.
The following are sample Digital Twin use cases that require Digital
Map:
* Generic inventory queries
* Service placement feasibility checks
* Service-> subservice -> resource
* Resource -> subservice -> service
* Intent/service assurance
* Service E2E and per-link KPIs on the Digital Map (delay, jitter,
and loss)
* Capacity planning
* Network design
* Simulation
* Closed loop
Overall, the Digital Map is needed to break down data islands and
have a Digital Twin for emulation and closed loop, which is a
catalyst for autonomous networking.
3. The IETF Network Topology Approaches
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3.1. IETF Network Topology
[RFC8345] provides a simple generic topological model. It defines
the abstract /generic /base model for network and service topologies.
It provides the mechanism to model networks and services as layered
topologies with common relationships at the same layer and underlay/
overlay relationships between the layers.
[RFC8345] consists of two modules: 'ietf-network' and 'ietf-network-
topology'. The 'ietf-network' module defines networks and nodes,
while 'ietf-network-topology' module adds definitions for links and
termination points.
The relationships inside the layer are containment/aggregation (a
network has nodes, a network has links, a node has termination
points), source (a link has one source termination point) and
destination (a link has one destination termination point).
The relationships between the layers are modelled via supporting
relationship:
* network A is supported by network B - this may model overlay/
underlay relationship
* nodes, links and termination points of network A are supported by
nodes, links and termination points of network B.
Overlay and underlay nodes, links and termination points must
match underlay and overlay networks supporting it
3.2. IETF Network Topology TE
[RFC8795] defines a YANG model for representing, retrieving and
manipulating traffic engineering (TE) topologies. This is a more
complex model which augments [RFC8345] with TE topology information
as follows:
* TE nodes, links, and termination points are defined using the core
RFC8345 concepts
- TE topology augments 'ietf-network' with topology identifier
(provider, client and topology id), as well as other 'TE'
information
- TE node augments 'node' with 'te-node-id' and other 'TE'
information
- TE link augments 'link' with 'TE' information
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- TE termination point augments termination point with 'te-tp-id'
and 'TE' information
* Tunnel, tunnel termination point, local link connectivity, node
connectivity matrix, and some supporting and underlay
relationships are defined outside of the core RFC 8345 entities
and relationships
4. Digital Map Requirements
<-- We discussed if requirements should be in a separate document.
We would leave them in this document for now, later we can create a
separate draft -->
The following are the core requirements for the Digital Map (note
that some of them are supported by default by [RFC8345]):
1. Basic model with network, node, link, and interface entity
types.
2. Layered Digital Map, from physical network (ideally optical,
layer 2, layer 3) up to customer service and intent views.
3. Open and programmable Digital Map: This includes "read"
operations to retrieve the view of the network, typically as
NorthBound Interface (NBI) of Software Defined Networking (SDN)
controllers or orchestrators. It also includes "write"
operations, not for the ability to directly change the Digital
Map data (e.g., changing the network or service parameters), but
for offline simulations, also known as what-if scenarios.
Running a "what-if" analysis requires the ability to take
snapshots and to switch easily between them. Note that there is
a need to distinguish between a change on the Digital Map for
future simulation and a change that reflects the current reality
of the network.
4. Standard based Digital Map Models and APIs, for multi-vendor
support: Digital Map must provide the standard APIs that provide
for read/write and queries. These APIs must also provide the
capability to retrieve the links to external data/models.
5. Digital Map models and APIs must be common over different
network domains (campus, core, data center, etc.)
6. Digital Map must provide semantics for layered network
topologies and for linking external models/data.
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7. Digital Map must provide inter-layer and between layer
relationships.
8. Digital Map must be extensible with metadata.
9. Digital Map must be pluggable:
* Must connect to other YANG modules for inventory,
configuration, assurance, etc.
* Given that no all involved components can be available using
YANG, there is a need to connect digital map YANG model with
other modelling mechanisms.
10. Digital Map must be optimized for graph traversal for paths.
This means that only providing link nodes and source and sink
relationships to termination-points may not be sufficient, we
may need to have the direct relationship between the termination
points or nodes.
4.1. Why RFC8345 is a Good Approach for Digital Map Modelling
The main reason for selecting RFC8345 for modelling is its simplicity
and that is supports majority of the core requirements. The
requirements [1-7] are automatically fulfilled with RFC8345 and
extensions:
* Basic model with network, node, link and interface entity types
* Layered topology
* Open and programmable
* Standard, multi-vendor
* Multi-domain
* Semantics for layered topology
* Inter-layer and between-layer relationships
The requirements [6-7] for semantics for layered topology and
relationships are partially fulfilled, there may be need for some
additional semantics. Other core requirements [8-10] are not
supported by RFC8345:
* Extensible with metadata
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* Pluggable to other YANG modules and non-YANG data
* Optimized for graph traversal
In some cases, for [9] for pluggable to other YANG modules, the links
are already done by augmenting 'ietf-network' and 'ietf-network-
topology'. For others, we need to add some mechanisms to link the
models and data.
4.2. Design Requirements
The following are design requirements for modelling the Digital Map:
1. Digital Map should contain only topological information. Digital
Map is not required to contain all data required for all the
management and use cases. However, it should be designed to
support adequate pointers to other functional Digital Twin data
and models to ease navigating in the overall system. For
example:
* ACLs and Route Policies are not required to be supported in the
Digital Map, they would be linked to Digital Map
* Dynamic paths may either be outside of the Digital Map or part of
traffic engineering data/models
1. Digital Map entities should mainly contain properties used to
identify topological entities at different layers, identify their
roles, and topological relationships between them.
2. Digital Map should contain only topological relationships inside
each layer or between the layers (underlay/overlay).
3. Provide capability for conditional retrieval of parts of Digital
Map.
4. Must support geo-spatial, temporal, and historical data. The
temporal and historical can be supported external to the Digital
Map.
The following are the architectural requirements for the Digital Map:
1. Scale, performance, ease of integration
2. Initial discovery and dynamic (change only) synch with the
physical network
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5. Digital Map Modelling Experience
5.1. What Is Not in The Base Model?
Based on some shared experience, the following are listed as set of
candidate extensions to [RFC8345] for Digital Map modelling and APIs:
* An alternate approach to model bidirectional links
* An alternate approach to multi-point connectivity
* Links between domains/networks
* A network decomposition into sub-networks
* Nodes, links, and termination points belonging to different
networks
* Supporting relationships between different types of entities
* More network topology related semantic is needed
5.1.1. Bidirectional Links
One of the core characteristics of any network topology is the link
directionality. While data flows are unidirectional, the
bidirectional links are also common in networking. Examples are
Ethernet cables, bidirectional SONET rings, socket connection to the
server, etc. We also encounter requirements for simplified service
layer topology, where we want to model link as bidirectional to be
supported by unidirectional links at the lower layer.
[RFC8345] defines all links as unidirectional, it does not support
bidirectional links. It was done intentionally to keep the model as
simple as possible. While simplifying the model itself, the data and
APIs are more complex for the cases with bidirectional links. In
such cases, there is no need to increase the amount of instances /
data transferred via API, stored in the database, or managed/
monitored by modeling unidirectional links.
This document suggests to model the bidirectional connections as
pairs of unidirectional links.
[I-D.davis-opsawg-some-refinements-to-rfc8345] further elaborates on
the need for bidirectional links in the network topologies and in the
Digital Map. It also proposes how RFC8345 can be augmented to
support missing components.
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The following are the candidate approaches of how we can address this
limitation:
* Use the current RFC8345 approach and implement it via multiple
unidirectional links
* Don't change RFC8345, leave to different augmentations to solve
the problem their own way
* Augment RFC8345 via basic approach as suggested in
[I-D.davis-opsawg-some-refinements-to-rfc8345], fully backward
compatible, appears simple and sufficient
* Augment RFC8345 via more sophisticated approach as suggested in
[I-D.davis-opsawg-some-refinements-to-rfc8345], more complex but
improves the integrity of the model, same instance structures
produced
* Consider RFC8345bis
We suggest to start the work on RFC8345bis to provide the backward
compatible way to support bidirectional links in the core topology
model defined in ietf-network-topology. The starting point can be
the basic approach from
[I-D.davis-opsawg-some-refinements-to-rfc8345] that adds the
following:
* direction-of-link with value BIDIRECTIONAL
* direction-of-point with value BIDIRECTIONAL
* list of termination points that could be used for bidirectional
links as an alternative to having source and destination for
unidirectional (although we can also implement it via the existing
source and destination when direction BIDIRECTIONAL)
5.1.2. Multipoint Connectivity
The RFC8345 defines all links as point to point and unidirectional,
it does not support multi-point links (hub and spoke, full mesh,
complex). It was done intentionally to keep the model as simple as
possible. The RFC suggests to model the multi-point networks via
pseudo nodes.
Same as with unidirectionality, while simplifying the model itself,
we are making data and APIs more complex for multi point topologies
and we are increasing the amount of data transferred via API, stored
in the database or managed/monitored.
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One of the core characteristics of any network topology is its type
and link cardinality. Any topology model should be able to model any
topology type in a simple and explicit way, including point to
multipoint, bus, ring, star, tree, mesh, hybrid and daisy chain. Any
topology model should also be able to model any link cardinality in a
simple and explicit way, including point to point, point to
multipoint, multipoint to multipoint or hybrid.
By forcing the implementation of all topology types and all options
for cardinality via unidirectional links and pseudo nodes, we are
significantly increasing the complexity of APIs and data, but also
lacking full topology semantics in the model. The model cannot be
fully used to validate if topology instances are valid or not.
Note that the point to multipoint network type is also required in
some cases at the OSPF layer.
[I-D.davis-opsawg-some-refinements-to-rfc8345] further elaborates on
the need for multipoint connectivity in network topologies and in the
Digital Map, in general. It also proposes how RFC8345 can be
augmented to support these missing components.
The following are the candidate approaches of how we can address this
limitation:
* Use the current RFC8345 and implement via virtual nodes
* Don't change RFC8345, leave to different augmentations to solve
the problem their own way (see how it is done in [RFC8795])
* Augment RFC8345 via basic approach as suggested in
[I-D.davis-opsawg-some-refinements-to-rfc8345], fully backward
compatible, appears simple and sufficient
* Augment RFC8345 via more sophisticated approach as suggested in
[I-D.davis-opsawg-some-refinements-to-rfc8345], more complex but
improves the integrity of the model, same instance structures
produced
* Consider a RFC8345bis that provides backward compatible
enhancement (similar to
[I-D.davis-opsawg-some-refinements-to-rfc8345] approach without
augmentations)
We suggest to start to work on RFC8345 bis to provide the backward
compatible way to support multipoint connectivity in the core
topology model defined in ietf-network-topology. The starting point
can be the basic approach from
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[I-D.davis-opsawg-some-refinements-to-rfc8345] that adds the
following: * list of termination points for multipoint links as an
alternative to having source and destination for point to point links
via the existing source and destination * role-of-point * type-of-
link
5.1.3. Links Between Networks
The RFC8345 defines all links as belonging to one network instance
and having the source and destination as node and termination point
only, not allowing to link to termination point of another network.
This does not allow for links between networks in the case of multi-
domains or partitioning. The only way would be to model each domain
as node and have links between them.
In our IS-IS PoC (following [I-D.ogondio-opsawg-isis-topology]), we
modelled IS-IS areas as networks and we needed to extend the
capability to have links between different areas. We added network
reference as well to the source / destination of the link. The
[RFC8795] also augments links with external-domain info for the case
of links that connect different domains.
The IS-IS topology [I-D.ogondio-opsawg-isis-topology] models
Autonomous System (AS) or IS-IS domain as a network, and IS-IS areas
as attributes of IS-IS nodes. The RFC8345 extension can be used to
model IS-IS areas as networks and IS-IS links between L1-2 nodes as
links between two different areas. This is not problem for OSPF,
although the OSPF nodes can belong to multiple areas, the links can
belong to only one area.
The following are some benefits of lifting the RFC 8345 limitations
that all links must belong to only one network instance:
* IS-IS processes would be grouped in an area via the standard IETF
RFC8345 network->node relationship.
* Applications and algorithms will consume topologies based on the
generic entities and relationships, they will not need to
understand the meaning of specific IS-IS attributes.
* The approach would be aligned with the IS-IS topology model and
the IS-IS network view in manuals and documentation.
* Provide capability to link different IGP domains and links between
them.
* Link between multiple networks/sub-networks is the common concept
in network topology.
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The following are the candidate approaches of how we can address this
limitation:
* Use the current RFC8345 and implement domains via properties in
augmentations
* Don't change RFC8345, leave to different augmentations to solve
the problem their own way (see how it is done in [RFC8795])
* Augment RFC8345 by adding some simple solution (e.g. move
[RFC8795] approach for multi-domain to RFC8345 digital map)
* Consider a RFC8345bis
We suggest to start to work on RFC8345 bis to provide the backward
compatible way to support links between networks in the core topology
model defined in ietf-network-topology. The starting point can be to
evaluate the approach from [RFC8795] that adds the external domain
reference to the link via the external network, node and tp
reference.
5.1.4. Networks Part of Other Networks
RFC8345 does not model networks being part of other networks,
therefore cannot model subnetworks and network partitioning. We
encountered this problem with modelling IS-IS and OSPF domains and
areas. The initial goal was to model AS/domain with multiple areas
so that the Digital Map model contains information about how the AS
is first split into different IGP domains and how each IGP domain is
split into different areas. This is a common problem for both IS-IS
and OSPF.
The following are the candidate approaches of how we can address this
limitation:
* Leave it as it is in RFC8345, don't model AS and IS-IS/OSPF domain
directly, they would be modelled via the underlying IP network and
IS-IS/OSPF enabled routers. This could be achieved via supporting
relationship to L3 network and L3 nodes
* Leave it as it is in RFC8345, leave to different augmentations to
solve the problem their own way
* Leave it as it is in RFC8345, model AS, IGP domains and areas as
networks and use supporting relationship to model the network
topology design, with only areas having nodes. This does not
describe the correct nature of the relationship, semantic is
missing.
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* Augment RFC8345 by adding some simple solution to support
additional partitioning relationship between networks.
* Consider a RFC8345bis
We suggest to start to work on RFC8345 bis to provide the backward
compatible way to support partitioning of networks in the core
network model defined in ietf-network. The solution needs to add a
part-of relation between different networks, where one network (e.g.
OSPF Domain) can contain multiple networks (e.g. OSPF areas)
5.1.5. Nodes, tps and links in multiple networks
RFC8345 does not allow nodes and TPs to belong to multiple areas
without splitting them into separate entities with separate keys. In
OSPF case, we have nodes that can belong to different areas, but
interfaces can only belong to one area. In the case of IS-IS,
although all tutorial are stating that nodes can belong to one area
only, the IETF, openconfig and vendor yang models and CLI allow IS-IS
processes with all its interfaces to belong to multiple areas.
The following are the candidate approaches of how we can address this
limitation:
* Use the current RFC8345 approach, this is not the problem for read
but may be an issue for write for simulation as we would expect
that the interface lists in different nodes and networks be the
same without being able to validate.
* Augment RFC8345 to optionally allow nodes to be defined outside of
network tree and enable reference as an alternative to the
containment in the tree. This may be a bigger change to the
network topology approach as it would have bigger impact on the
topology tree. Nevertheless, it can be an optional approach so
would be backward compatible for those augmentations that do not
want to use it
* Consider RFC8345 bis
We suggest to work on RFC8345 bis to provide the simple backward
compatible way to support both the current RFC8345 approach of
creating multiple instances and the approach of sharing the
instances. The solution needs further analysis as it has bigger
impact on the topology tree than other enhancements.
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5.1.6. Missing Supporting Relationships
RFC8345 defines supporting relationships only between the same type
of entities. Networks can only be supported by networks, nodes can
only be supported by nodes, termination points can only be supported
by terminations points and links can only be supported by links.
During the PoC, we encountered the need to have TP supported by node
and node supported by Network. The RFC8795 also adds additional
underlay relationship between node and topology and link and
topology, but via a new underlay topology and not via the core
supporting relationship.
The following are the candidate approaches to address this
limitation:
* Use the current RFC8345 approach, leave to different augmentations
to solve the problem their own way (see how it is done in
[RFC8795])
* Augment RFC8345 by adding some simple solution (e.g. move
[RFC8795] approach to RFC8345)
* Consider RFC8345 bis that provides backward compatible enhancement
(e.g. via [RFC8795] basic approach)
We suggest to work on RFC8345 bis to provide the backward compatible
way to add the missing supporting relationships:
tp->supporting->node, node->supporting->network.
5.1.7. Missing Topology Semantics
We already mentioned that some semantic is missing from the RFC8345
topology model, like bidirectional and multi-point. The following is
also missing from the model:
* Relationship Properties. The supporting relationship could have
additional attributes that give more information about the
supporting relationship. That way we could use it for
aggregation, underlay with primary/backup, load balancing, hop,
sequence, etc.
* Termination point roles. We are missing semantics for the common
topology roles: primary, backup, hub, spoke
* Layers / Sublayers. We need further analysis to determine in
network types are sufficient to support all scenarios for layers/
sublayers. The network types are more related to technologies so
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in the case that the same technology is used at different layers,
we may need some additional information in the model. For further
study.
* Tunnels and paths. We modelled tunnels and paths via [RFC8345]
but we lost some semantics that is in [RFC8795] .
* Supporting or underlay. We modelled all underlay relationships
via supporting, further analysis is needed to determine pros and
cons of this approach versus RFC8795 approach of using underlay
topology.
The following are the candidate approaches to address this
limitation:
* Use the current RFC8345 approach, leave to different augmentations
to solve the problem their own way (see how it is done in
[RFC8795])
* Augment RFC8345 by adding some simple solution (e.g. move
[RFC8795] approach to RFC8345)
* Consider RFC8345bis
We suggest to work on RFC8345 bis to provide the backward compatible
way to add the minimum semantics that the community agrees is
required for the core topology. We need to further investigate the
[RFC8795] approach and evaluate if some parts could be moved to
RFC8345.
5.2. Open Issues (for Further Analysis or Resolved)
The following are the open issues that need further analysis or have
been resolved:
* Do we need separation of L2 and L3 topologies?
During the PoC we encountered different solutions with separate
set of requirements. In one solution, the L2 and L3 topology were
the same with separate set of attributes, while in another
solution we had difference in L2 and L3 topology (e.g. Links
Aggregation, Switches and Routers).
The RFC8944 defines L2 topology and RFC8346 defines the L3
topology. They allow to have either one or two instances of this
topology.
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The decision if we need separate network instances for L2 and L3
topologies may be based on specific network topology and
provider's preferences.
Resolved: the RFC8345 is flexible and it can support both the same
network instance with L2 + L3 augmentations or separate network
instances with supporting relationship between. The operator
should decide what option is needed for their solution.
* Do we need sublayers as well? Layers versus sublayers versus
layered instances?
Resolved: Layers/sublayers could be implemented via multiple
network types. The new data nodes for layer are present only when
the network type for the layer is present. The new data nodes for
the sublayer are present when the network types for both layer and
sublayer are present. The solution could also enable either
single or multiple instances, like in the previous point.
* Same technology at service versus underlay? BGP per VPN vs common
BGP shared between multiple VPNs. Different layers, same model,
relationship define the layer.
Further analysis is needed.
* There are potential circular dependencies in layering. For
example routing can be underlay for tunnels, but tunnel interface
can also be in the routing table.
* Further analysis is needed.
6. Digital Map Modeling Guidelines
6.1. Guidelines for Generic Digital Map Extensions
Generic Digital Map extensions are the RFC8345 extensions required
for all technologies and layers in the Digital Map. We already
discussed some options for individual limitations in the previous
sections, here is the summary:
1. Use the current RFC8345 approach, leave to different augmentations to solve the problem their own way
2. Augment RFC8345 network, node, link and termination point for any
changes needed from a new digital map module
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module: dm-network-topology
augment /nw:networks/nw:network:
.... additions
augment /nw:networks/nw:network/nw:node:
.... additions
augment /nw:networks/nw:network/nt:link:
.... additions
augment /nw:networks/nw:network/nw:node/nt:termination-point:
.... additions
// This can be a separate draft with describing pros and cons of
// different approaches and yang model proposal. Add reference to
// this draft when submitted
3. Make backward compatible updates to RFC8345, work on RFC8345 bis
The following are some important guidelines mentioned in the RFC8345
that should be taken into account when suggesting the approach:
* "The data models allow applications to operate on an inventory or
topology of any network at a generic level, where the specifics of
particular inventory/topology types are not required. At the same
time, where data specific to a network type comes into play and
the data model is augmented, the instantiated data still adheres
to the same structure and is represented in a consistent fashion.
This also facilitates the representation of network hierarchies
and dependencies between different network components and network
types"
* “It is possible for links at one level of a hierarchy to map to
multiple links at another level of the hierarchy.
For example, a VPN topology might model VPN tunnels as links.
Where a VPN tunnel maps to a path that is composed of a chain of
several links, the link will contain a list of those supporting
links. Likewise, it is possible for a link at one level of a
hierarchy to aggregate a bundle of links at another level of the
hierarchy."
Our recommendation on how to extend RFC8345 for Digital Map is to
stay in spirit of RFC8345 and augment with non-topological info only.
Reuse network, node, link, tp for all topological entities, reuse
supporting for layering and add new properties/attributes and
references to other modules Therefore, we suggest to work on RFC8345
bis to provide the backward compatible way to address all identified
limitations.
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The alternative of having the core topology augmentations in either
TE modules or technology specific modules is not generic enough and
is not in the spirit of having the core topology model to model
topology in the consistent manner between different technologies and
TE and non-TE topologies.
6.2. Guidelines for New Technologies/Layers Extensions
There are already drafts that support augmentation for specific
technologies. These drafts augment network, node, termination point
and link, but also add different topological entities inside
augmentations. For example, we have examples like this:
module: new-module
augment /nw:networks/nw:network/nw:network-types:
+--rw new-topology!
augment /nw:networks/nw:network:
....
augment /nw:networks/nw:network/nw:node:
.... adding list of tps of other type
(e.g. tunnel TPs in TE draft)
... adding new supporting relationship
supporting-tunnel-termination-point
(te draft)
augment /nw:networks/nw:network/nt:link:
.... adding tunnels (te draft)
augment /nw:networks/nw:network/nw:node/
nt:termination-point:
....
There is a need to agree some guidelines for augmenting IETF network
topology, so that additional topological information is not added in
the custom way. There is also need to categorize the current
augmentations and the impact of RFC 8345 bis based on what has been
added for different technologies:
* new properties/attributes (e.g. ietf-l2-topology, ietf-l3-unicast-
topology, ietf-isis-topology)
* new events (e.g. ietf-l2-topology)
* new topological entities (e.g. ietf-te-topology, ietf-dc-fabric-
topology)
* new topological relations (e.g. ietf-te-topology)
* type reuse (e.g. ietf-dots-telemetry, ietf-dc-fabric-types, ietf-
dc-fabric-topology)
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<-- This can be a separate draft. Guidelines with examples? Add
reference to this draft when submitted -->
6.3. Guidelines for Digital Maps Connectiont to Other Components
Digital Map must be pluggable:
* We must connect to other YANG modules for inventory,
configuration, assurance, etc
* Not everything can be in YANG, we need to connect digital map YANG
model with other modelling mechanisms, both southbound, northbound
and internally
Also, there are already some modules that connect network topology to
other YANG modules. We will investigate different approaches and
propose the best practices. The following are some existing
approaches proposed in IETF:
* How to connect network topology to interface
[I-D.draft-ietf-ccamp-if-ref-topo-yang]
* How to connect network topology to hardware inventory
[I-D.ietf-ccamp-network-inventory-yang]
* How to connect network topology to ivy inventory
[I-D.draft-wzwb-ivy-network-inventory-topology]
* How to connect network topology to performance monitoring
[RFC9375]
6.3.1. How to connect YANG models with other modelling mechanisms
There is need to connect YANG network topology to models and data
outside of YANG, for example BMP, IPFIX, logs, etc.
6.4. Digital Map APIs
This will include hierarchical APIs for cross-domain figure, IETF
YANG Based API (read and write, change subscription and notify) and
Query API
6.5. Digital Map Knowledge
The following knowledge was needed to build Digital Map:
* Abstract IETF Entities and Relationships as in [RFC8345]
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* [RFC8345] Augmentations for a)Layers/sublayers b)Entities
(services and subservices), c)Properties
* Rules for aggregating entities
* Rules for instantiating relationships (inter-layer and intra-
layer)
* Mapping from devices and controllers
What can be achieved with existing RFC8345 YANG:
* Entities (base class IETF Network, IETF Node, IETF Link, IETF TP)
* Properties
* Relationships
Next steps
* How to support temporal
* How to support spacial
* How to support historical
7. Related IETF Activities
7.1. Network Topology
Interestingly, we could not find any network topology definition in
IETF RFCs (not even in [RFC8345]) or drafts. However, it's mentioned
in multiple documents. As an example, in Overview and Principles of
Internet Traffic Engineering [I-D.ietf-teas-rfc3272bis], which
mentioned:
To conduct performance studies and to support planning of existing
and future networks, a routing analysis may be performed to determine
the paths the routing protocols will choose for various traffic
demands, and to ascertain the utilization of network resources as
traffic is routed through the network. Routing analysis captures the
selection of paths through the network, the assignment of traffic
across multiple feasible routes, and the multiplexing of IP traffic
over traffic trunks (if such constructs exist) and over the
underlying network infrastructure. A model of network topology is
necessary to perform routing analysis. A network topology model may
be extracted from:
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* Network architecture documents
* Network designs
* Information contained in router configuration files
* Routing databases such as the link state database of an interior
gateway protocol (IGP)
* Routing tables
* Automated tools that discover and collate network topology
information.
Topology information may also be derived from servers that monitor
network state, and from servers that perform provisioning functions.
7.2. Core Digital Map Components
The following standards are core for the Digital Map.
* IETF network model and network topology model [RFC8345]
* A YANG grouping for geographic location [RFC9179]
* IETF modules that augment [RFC8345] for different technologies:
* - A YANG data model for Traffic Engineering (TE) Topologies
[RFC8795]
* - A YANG data model for Layer 2 network topologies [RFC8944]
* - A YANG data model for OSFP topology
[I-D.ogondio-opsawg-ospf-topology]
* - A YANG data model for IS-IS topology
[I-D.ogondio-opsawg-isis-topology]
7.3. Additional Digital Map Components
The Digital Map may need to link to the following models, some are
already augmenting [RFC8345], we need further investigation for each
of these items:
* Service Access Point (SAP) [RFC9408], augments 'ietf-network' data
model [RFC8345] by adding the SAP.
* SAIN [RFC9417] and [RFC9418]
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* Network Inventory Model
[I-D.draft-ietf-ivy-network-inventory-yang] is the latest
inventory model proposed by ivy, focusing on physical and virtual
inventory. Logical inventory is currently outside of the scope.
It does not augment RFC8345 like the two drafts that it evolved
from [I-D.ietf-ccamp-network-inventory-yang] and
[I-D.wzwb-opsawg-network-inventory-management]. The
[I-D.draft-wzwb-ivy-network-inventory-topology] correlates the
network inventory with the general topology via RFC8345
augmentations that reference inventory.
* Data Model for Lifecycle Management and Operations
[I-D.palmero-opsawg-dmlmo]
* KPIs: delay, jitter, loss
* Attachment Circuits (ACs) [I-D.boro-opsawg-ntw-attachment-circuit]
and [I-D.boro-opsawg-teas-attachment-circuit]
* Configuration: L2SM [RFC8466], L3SM [RFC8299], L2NM [RFC9291],
L3NM [RFC9182]
* Incident Management for Network Services
[I-D.feng-opsawg-incident-management]
7.4. Network Inventory (IVY) Proposed Working
The charter of the Network Inventory (IVY) IETF Working Group (WG)
can be found at https://datatracker.ietf.org/doc/charter-ietf-ivy/.
Understanding how the two efforts complement each other is important.
The IVY effort focuses on the network inventory (as the charter says,
"including a variety of information such as product name, vendor,
product series, embedded software, and hardware/software versions").
The network inventory is probably the first use cases for the digital
map. Therefore, it is important to have a consistent view of what a
network node is. While a Digital Map must include a pointer to the
hardware and software inventory information, we don't consider that
all the inventory information is actually part of the Digital Map.
It must also be noted that the set of use cases for the Digital Map
is wider than just the network inventory.
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The IVY charter also says that, "The Working Group will consider
existing IETF work, including RFC 8348 and RFC 8345.". In this
document, RFC 8345 is considered as the base YANG module, therefore,
there is clearly common ground with the work of the ivy working
group. This document goes beyond RFC 8345 to evaluate whether that
RFC, along with all the augmented YANG modules, would be a good fit
for all the Digital Map requirements.
Additionally, the IVY charter says, "The WG will also identify a set
of requirements and guidelines to ensure consistency across models
related to inventory." While the IVY requirements and guidelines
focus on inventory, this document looks at the full set of
requirements, guidelines, and building blocks for all the Digital Map
use cases. The inventory use case does not cover that full set, and
other building blocks will be required: for example, to support
point-to-multipoint connectivity
Thus, this Digital Map modelling effort is complementary to the
inventory work in IVY. It has a broader outlook covering all Digital
Map use case requirements, and will correlate with the existing IETF
models, e.g., topology, service attachment points (SAP), etc.
8. Conclusions
Digital Map Modelling and Data are basis for the Digital Twin.
During our PoC we have proven that Digital Map can be modelled using
[RFC8345]. Nevertheless, we proposed some extensions/augmentations
to [RFC8345] to support Digital Maps. There must be some constraints
in regards to how to augment the core Digital Map model for different
Layers and Technologies in order to support the approach recommended
in RFC8345 and implemented in our PoC. All entities must augment
IETF node, IETF network, IETF link or IETF Termination Point and
augmentation can only include new properties, events, references.
We suggest to start the work on RFC8345 bis to provide the backward
compatible way to support the following basic topological features:
* bidirectional links
* multipoint connectivity
* cross-domain links via links between networks
* multi-domain via network partitioning
* shared topological entities between different domains
* additional supporting relations
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* additional semantics required for core topologies
9. Security Considerations
This section uses the template described in Section 3.7 of
[I-D.ietf-netmod-rfc8407bis].
The YANG modules cited in this document define 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.
The specifications that define these modules call out both sensitive
and vulnerable writable and readable data nodes. These
considerations are not reiterated here.
10. IANA Considerations
This document has no actions for IANA.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/rfc/rfc6241>.
[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>.
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[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>.
[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>.
[RFC8944] Dong, J., Wei, X., Wu, Q., Boucadair, M., and A. Liu, "A
YANG Data Model for Layer 2 Network Topologies", RFC 8944,
DOI 10.17487/RFC8944, November 2020,
<https://www.rfc-editor.org/rfc/rfc8944>.
11.2. Informative References
[Catalog] YANG Catalog, "YANG Impact Analysis", n.d.,
<https://yangcatalog.org/yang-search/impact_analysis/ietf-
network-topology@2018-02-26>.
[I-D.boro-opsawg-ntw-attachment-circuit]
Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S.,
and B. Wu, "A Network YANG Data Model for Attachment
Circuits", Work in Progress, Internet-Draft, draft-boro-
opsawg-ntw-attachment-circuit-03, 5 September 2023,
<https://datatracker.ietf.org/doc/html/draft-boro-opsawg-
ntw-attachment-circuit-03>.
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[I-D.boro-opsawg-teas-attachment-circuit]
Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S.,
and B. Wu, "YANG Data Models for 'Attachment Circuits'-as-
a-Service (ACaaS)", Work in Progress, Internet-Draft,
draft-boro-opsawg-teas-attachment-circuit-07, 10 July
2023, <https://datatracker.ietf.org/doc/html/draft-boro-
opsawg-teas-attachment-circuit-07>.
[I-D.davis-opsawg-some-refinements-to-rfc8345]
Davis, N., Havel, O., and B. Claise, "Some Refinements to
Network Topologies (RFC8345)", Work in Progress, Internet-
Draft, draft-davis-opsawg-some-refinements-to-rfc8345-01,
10 January 2024, <https://datatracker.ietf.org/doc/html/
draft-davis-opsawg-some-refinements-to-rfc8345-01>.
[I-D.draft-ietf-ccamp-if-ref-topo-yang]
Ahlberg, J., Mansfield, S., Ye, M., Busi, I., Li, X., and
D. Spreafico, "A YANG Data Model for Interface Reference
Topology", Work in Progress, Internet-Draft, draft-ietf-
ccamp-if-ref-topo-yang-01, 18 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
if-ref-topo-yang-01>.
[I-D.draft-ietf-ivy-network-inventory-yang]
Yu, C., Belotti, S., Bouquier, J., Peruzzini, F., and P.
Bedard, "A YANG Data Model for Network Inventory", Work in
Progress, Internet-Draft, draft-ietf-ivy-network-
inventory-yang-00, 5 December 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-ivy-
network-inventory-yang-00>.
[I-D.draft-wzwb-ivy-network-inventory-topology]
Wu, B., Zhou, C., Wu, Q., and M. Boucadair, "A Network
Inventory Topology Model", Work in Progress, Internet-
Draft, draft-wzwb-ivy-network-inventory-topology-00, 18
October 2023, <https://datatracker.ietf.org/doc/html/
draft-wzwb-ivy-network-inventory-topology-00>.
[I-D.feng-opsawg-incident-management]
Feng, C., Hu, T., Contreras, L. M., Graf, T., Wu, Q., Yu,
C., and N. Davis, "Incident Management for Network
Services", Work in Progress, Internet-Draft, draft-feng-
opsawg-incident-management-04, 30 January 2024,
<https://datatracker.ietf.org/doc/html/draft-feng-opsawg-
incident-management-04>.
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[I-D.ietf-ccamp-network-inventory-yang]
Yu, C., Belotti, S., Bouquier, J., Peruzzini, F., and P.
Bedard, "A YANG Data Model for Network Hardware
Inventory", Work in Progress, Internet-Draft, draft-ietf-
ccamp-network-inventory-yang-02, 9 July 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
network-inventory-yang-02>.
[I-D.ietf-ivy-network-inventory-yang]
Yu, C., Belotti, S., Bouquier, J., Peruzzini, F., and P.
Bedard, "A YANG Data Model for Network Inventory", Work in
Progress, Internet-Draft, draft-ietf-ivy-network-
inventory-yang-00, 5 December 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-ivy-
network-inventory-yang-00>.
[I-D.ietf-netmod-rfc8407bis]
Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
Authors and Reviewers of Documents Containing YANG Data
Models", Work in Progress, Internet-Draft, draft-ietf-
netmod-rfc8407bis-09, 28 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
rfc8407bis-09>.
[I-D.ietf-teas-rfc3272bis]
Farrel, A., "Overview and Principles of Internet Traffic
Engineering", Work in Progress, Internet-Draft, draft-
ietf-teas-rfc3272bis-27, 12 August 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
rfc3272bis-27>.
[I-D.irtf-nmrg-network-digital-twin-arch]
Zhou, C., Yang, H., Duan, X., Lopez, D., Pastor, A., Wu,
Q., Boucadair, M., and C. Jacquenet, "Digital Twin
Network: Concepts and Reference Architecture", Work in
Progress, Internet-Draft, draft-irtf-nmrg-network-digital-
twin-arch-04, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-irtf-nmrg-
network-digital-twin-arch-04>.
[I-D.ogondio-opsawg-isis-topology]
de Dios, O. G., Barguil, S., Lopez, V., Ceccarelli, D.,
and B. Claise, "A YANG Data Model for Intermediate System
to intermediate System (IS-IS) Topology", Work in
Progress, Internet-Draft, draft-ogondio-opsawg-isis-
topology-01, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ogondio-
opsawg-isis-topology-01>.
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[I-D.ogondio-opsawg-ospf-topology]
de Dios, O. G., Barguil, S., and V. Lopez, "A YANG Data
Model for Open Shortest Path First (OSPF) Topology", Work
in Progress, Internet-Draft, draft-ogondio-opsawg-ospf-
topology-01, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ogondio-
opsawg-ospf-topology-01>.
[I-D.palmero-opsawg-dmlmo]
Palmero, M., Brockners, F., Kumar, S., Bhandari, S.,
Cardona, C., and D. Lopez, "Data Model for Lifecycle
Management and Operations", Work in Progress, Internet-
Draft, draft-palmero-opsawg-dmlmo-10, 7 July 2023,
<https://datatracker.ietf.org/doc/html/draft-palmero-
opsawg-dmlmo-10>.
[I-D.wzwb-opsawg-network-inventory-management]
Wu, B., Zhou, C., Wu, Q., and M. Boucadair, "A YANG
Network Data Model of Network Inventory", Work in
Progress, Internet-Draft, draft-wzwb-opsawg-network-
inventory-management-04, 19 October 2023,
<https://datatracker.ietf.org/doc/html/draft-wzwb-opsawg-
network-inventory-management-04>.
[RFC8299] Wu, Q., Ed., Litkowski, S., Tomotaki, L., and K. Ogaki,
"YANG Data Model for L3VPN Service Delivery", RFC 8299,
DOI 10.17487/RFC8299, January 2018,
<https://www.rfc-editor.org/rfc/rfc8299>.
[RFC8466] Wen, B., Fioccola, G., Ed., Xie, C., and L. Jalil, "A YANG
Data Model for Layer 2 Virtual Private Network (L2VPN)
Service Delivery", RFC 8466, DOI 10.17487/RFC8466, October
2018, <https://www.rfc-editor.org/rfc/rfc8466>.
[RFC9179] Hopps, C., "A YANG Grouping for Geographic Locations",
RFC 9179, DOI 10.17487/RFC9179, February 2022,
<https://www.rfc-editor.org/rfc/rfc9179>.
[RFC9182] Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M.,
Ed., Munoz, L., and A. Aguado, "A YANG Network Data Model
for Layer 3 VPNs", RFC 9182, DOI 10.17487/RFC9182,
February 2022, <https://www.rfc-editor.org/rfc/rfc9182>.
[RFC9291] Boucadair, M., Ed., Gonzalez de Dios, O., Ed., Barguil,
S., and L. Munoz, "A YANG Network Data Model for Layer 2
VPNs", RFC 9291, DOI 10.17487/RFC9291, September 2022,
<https://www.rfc-editor.org/rfc/rfc9291>.
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[RFC9375] Wu, B., Ed., Wu, Q., Ed., Boucadair, M., Ed., Gonzalez de
Dios, O., and B. Wen, "A YANG Data Model for Network and
VPN Service Performance Monitoring", RFC 9375,
DOI 10.17487/RFC9375, April 2023,
<https://www.rfc-editor.org/rfc/rfc9375>.
[RFC9408] Boucadair, M., Ed., Gonzalez de Dios, O., Barguil, S., Wu,
Q., and V. Lopez, "A YANG Network Data Model for Service
Attachment Points (SAPs)", RFC 9408, DOI 10.17487/RFC9408,
June 2023, <https://www.rfc-editor.org/rfc/rfc9408>.
[RFC9417] Claise, B., Quilbeuf, J., Lopez, D., Voyer, D., and T.
Arumugam, "Service Assurance for Intent-Based Networking
Architecture", RFC 9417, DOI 10.17487/RFC9417, July 2023,
<https://www.rfc-editor.org/rfc/rfc9417>.
[RFC9418] Claise, B., Quilbeuf, J., Lucente, P., Fasano, P., and T.
Arumugam, "A YANG Data Model for Service Assurance",
RFC 9418, DOI 10.17487/RFC9418, July 2023,
<https://www.rfc-editor.org/rfc/rfc9418>.
Acknowledgments
Thanks to xx for their reviews and comments.
Contributors
Nigel Davis
Ciena
Email: ndavis@ciena.com
Authors' Addresses
Olga Havel
Huawei
Email: olga.havel@huawei.com
Benoit Claise
Huawei
Email: benoit.claise@huawei.com
Oscar González de Dios
Telefonica
Email: oscar.gonzalezdedios@telefonica.com
Havel, et al. Expires 4 September 2024 [Page 34]
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Ahmed Elhassany
Swisscom
Email: Ahmed.Elhassany@swisscom.com
Thomas Graf
Swisscom
Email: thomas.graf@swisscom.com
Mohamed Boucadair
Orange
Email: mohamed.boucadair@orange.com
Havel, et al. Expires 4 September 2024 [Page 35]
