Profiles for Traffic Engineering (TE) Topology Data Model and Applicability to non-TE-centric Use Cases
draft-ietf-teas-te-topology-profiles-04
| Document | Type | Active Internet-Draft (teas WG) | |
|---|---|---|---|
| Authors | Italo Busi , Xufeng Liu , Igor Bryskin , Tarek Saad , Oscar Gonzalez de Dios | ||
| Last updated | 2025-10-20 | ||
| Replaces | draft-busi-teas-te-topology-profiles | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-teas-te-topology-profiles-04
TEAS Working Group I. Busi
Internet-Draft Huawei
Intended status: Informational X. Liu
Expires: 23 April 2026 Alef Edge
I. Bryskin
Individual
T. Saad
Cisco Systems Inc
O. Gonzalez de Dios
Telefonica
20 October 2025
Profiles for Traffic Engineering (TE) Topology Data Model and
Applicability to non-TE-centric Use Cases
draft-ietf-teas-te-topology-profiles-04
Abstract
This document describes how profiles of the Topology YANG data model,
defined in RFC8795, can be used to address applications in Traffic
Engineering aware (TE-aware) deployments, irrespective of whether
they are TE-centric or not.
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 23 April 2026.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
Busi, et al. Expires 23 April 2026 [Page 1]
Internet-Draft TE Topology Profiles October 2025
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
2. Examples of generic profiles . . . . . . . . . . . . . . . . 4
2.1. UNI Topology Discovery . . . . . . . . . . . . . . . . . 4
2.2. Administrative and Operational status management . . . . 5
2.3. Overlay and Underlay Topologies . . . . . . . . . . . . . 6
2.3.1. Supporting relationships in RFC8345 . . . . . . . . . 8
2.4. Nodes with switching limitations . . . . . . . . . . . . 8
2.5. Multipoint links . . . . . . . . . . . . . . . . . . . . 9
3. Technology-specific augmentations . . . . . . . . . . . . . . 12
3.1. Multi-inheritance . . . . . . . . . . . . . . . . . . . . 14
3.2. Example (Link augmentation) . . . . . . . . . . . . . . . 15
4. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1. Implemented profiles . . . . . . . . . . . . . . . . . . 16
5. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Normative References . . . . . . . . . . . . . . . . . . . . . 17
Informative References . . . . . . . . . . . . . . . . . . . . 18
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
Many network scenarios are being discussed in various IETF Working
Groups (WGs) that are not classified as "Traffic Engineering" use
cases but can be addressed by a profile (sub-set) of the Topology
YANG data model, defined in [RFC8795].
Traffic Engineering (TE) is defined in [I-D.ietf-teas-rfc3272bis] as
aspects of Internet network engineering that deal with the issues of
performance evaluation and performance optimization of operational IP
networks. TE encompasses the application of technology and
scientific principles to the measurement, characterization, modeling,
and control of Internet traffic.
Busi, et al. Expires 23 April 2026 [Page 2]
Internet-Draft TE Topology Profiles October 2025
The Topology YANG data model, defined in [RFC8795], augments the
Network Topology YANG data model, defined in [RFC8345], with generic
and technology-agnostic features that are not only applicable to TE-
centric deployments, but also applicable to non-TE-centric yet TE-
aware deployments.
A TE-aware deployment is one where the topology carries information
that can be used to influence how traffic can be engineered within
the network. In some scenarios, this information can be leveraged
even in use cases where traffic doesn't need to be engineered.
Examples of generic TE-aware features that can apply to both TE-
centric and non-TE-centric use-cases are: inter-domain link discovery
(plug-id), geo-localization, multi-layer topology representation,
node-specific switching limitation, link reliability, and topology
abstraction.
It is also worth noting that also the boundary between the TE-
specific model constructs and the core network topology model
constructs is also blurred since new applications may need to
leverage on constructs which was originally defined to support TE-
centric scenarios but that are also needed to support these new
applications.
An example of a concept that originated from TE-centric scenarios but
can be considered a core network topology model construct is the
SRLG. New applications such as what-if analysis need to be aware of
the SRLG information also for non-TE-centric scenarios to provide
reliable results.
It is also worth noting that the Topology YANG data model, defined in
[RFC8795], is quite an extensive and comprehensive model in which
most features are optional. Therefore, even though the full model
appears to be complex, at the first glance, a profile (sub-set) of
the model can be used to address specific scenarios irrespective of
whether they are TE-centric or not.
The implementation of profiles can simplify and expedite adoption of
the Topology YANG data model, defined [RFC8795], and allow for its
reuse even for non-TE-centric use-cases. The key question is whether
all or some of the attributes defined in the Topology YANG data
model, defined in [RFC8795], are needed to address a given network
scenario.
Section 2 provides examples where profiles of the Topology YANG data
model, defined in [RFC8795], can be used to address some generic use
cases applicable to both TE-centric and non-TE-centric deployments.
Busi, et al. Expires 23 April 2026 [Page 3]
Internet-Draft TE Topology Profiles October 2025
Understanding that these profiles are generic would be more
straightforward if the profiled YANG data nodes where defined under a
container with a different name than 'te' or directly under the
parent YANG data node. However, the 'te' container in the context of
[RFC8795], should be understood as the container of YANG data nodes
providing TE-aware topology information.
2. Examples of generic profiles
2.1. UNI Topology Discovery
The following profile of the Topology YANG data model, defined in
[RFC8795], can be used to support the UNI Topology Discovery, or in
general, inter-domain link discovery:
module: ietf-te-topology
augment /nw:networks/nw:network/nw:network-types:
+--rw te-topology!
augment /nw:networks/nw:network/nw:node/nt:termination-point:
+--rw te-tp-id? te-types:te-tp-id
+--rw te!
+--rw admin-status?
| te-types:te-admin-status
+--rw inter-domain-plug-id? binary
+--ro oper-status? te-types:te-oper-status
Figure 1: UNI Topology
It is also worth noting that the UNI links can also be TE (e.g. an
OTN UNI) or non-TE (e.g., an Ethernet UNI) as well as multi-function
UNI links, supporting both TE and non-TE technologies, such as the
UNI links, described in Section 4.4 of
[I-D.ietf-ccamp-transport-nbi-app-statement], which can be configured
either OTN UNI or Ethernet UNI or SDH UNI.
The UNI Topology profiled YANG data model shown in Figure 1 can also
be used with technology-specific UNI augmentations, as described in
Section 3. Technology-specific augmentations can for example
describe the capability of the TP to be configured as a UNI for the
types of services supported by the UNI (e.g., L2VPN/L3VPN).
For example, in [I-D.ietf-ccamp-eth-client-te-topo-yang], the eth-svc
container is defined to represent the capabilities of the Termination
Point (TP) to be configured as an Ethernet UNI, together with the
Ethernet classification and VLAN operations supported by that TP.
The [I-D.ietf-ccamp-otn-topo-yang] provides another example, where:
Busi, et al. Expires 23 April 2026 [Page 4]
Internet-Draft TE Topology Profiles October 2025
* the client-svc container is defined to represent the capabilities
of the TP to be configured as an transparent client UNI (e.g.,
STM-N, Fiber Channel or transparent Ethernet);
* the OTN technology-specific Link Termination Point (LTP)
augmentations are defined to represent the capabilities of the TP
to be configured as an OTN UNI, together with the information
about OTN label and bandwidth availability at the OTN UNI.
Te UNI Topology profiled YANG data model shown in Figure 1 does not
require the network to be a TE network and, therefore, it could be
used as a core network topology model to discover UNIs (or in general
any external link) for TE and non-TE networks as well as multi-layer
networks encompassing both TE and non-TE layers.
The advantages of using the UNI Topology profiled YANG data model
shown in Figure 1 as a core network topology model is to have a
common solutions for:
* discovering UNIs as well as inter-domain NNI links, which is
applicable to any technology (TE or non TE) used at the UNI or
within the network;
* modelling non TE UNIs such as Ethernet, and TE UNIs such as OTN,
as well as UNIs which can configured as TE or non-TE (e.g., being
configured as either Ethernet or OTN UNI).
2.2. Administrative and Operational status management
The following profile of the Topology YANG data model, defined in
[RFC8795], can be used to manage the administrative and operational
for nodes, termination points and links as well as to associate some
administrative names to network topologies, nodes, termination points
and links:
Busi, et al. Expires 23 April 2026 [Page 5]
Internet-Draft TE Topology Profiles October 2025
module: ietf-te-topology
augment /nw:networks/nw:network/nw:network-types:
+--rw te-topology!
augment /nw:networks/nw:network:
+--rw te-topology-identifier
| +--rw provider-id? te-global-id
| +--rw client-id? te-global-id
| +--rw topology-id? te-topology-id
+--rw te!
+--rw name? string
augment /nw:networks/nw:network/nw:node:
+--rw te-node-id? te-types:te-node-id
+--rw te!
+--rw te-node-attributes
| +--rw admin-status? te-types:te-admin-status
| +--rw name? string
+--ro oper-status? te-types:te-oper-status
augment /nw:networks/nw:network/nt:link:
+--rw te!
+--rw te-link-attributes
| +--rw name? string
| +--rw admin-status? te-types:te-admin-status
+--ro oper-status? te-types:te-oper-status
augment /nw:networks/nw:network/nw:node/nt:termination-point:
+--rw te-tp-id? te-types:te-tp-id
+--rw te!
+--rw admin-status? te-types:te-admin-status
+--rw name? string
+--ro oper-status? te-types:te-oper-status
Figure 2: Generic Topology with admin and operational state
2.3. Overlay and Underlay Topologies
The following profile of the Topology YANG data model, defined in
[RFC8795], can be used to manage the overlay/underlay relationships
for nodes and links, as described in section 5.8 of [RFC8795]:
Busi, et al. Expires 23 April 2026 [Page 6]
Internet-Draft TE Topology Profiles October 2025
module: ietf-te-topology
augment /nw:netorks/nw:network/nw:network-types:
+--rw te-topology!
augment /nw:networks/nw:network/nw:node:
+--rw te-node-id? te-types:te-node-id
+--rw te!
+--rw te-node-attributes
+--rw underlay-topology {te-topology-hierarchy}?
+--rw network-ref? -> /nw:networks/network/network-id
augment /nw:networks/nw:network/nt:link:
+--rw te!
+--rw te-link-attributes
+--rw underlay {te-topology-hierarchy}?
+--rw enabled? boolean
+--rw primary-path
+--rw network-ref?
| -> /nw:networks/network/network-id
+--rw path-element* [path-element-id]
+--rw path-element-id uint32
+--rw (type)?
+--:(numbered-link-hop)
| +--rw numbered-link-hop
| +--rw link-tp-id te-tp-id
| +--rw hop-type? te-hop-type
| +--rw direction? te-link-direction
+--:(unnumbered-link-hop)
+--rw unnumbered-link-hop
+--rw link-tp-id te-tp-id
+--rw node-id te-node-id
+--rw hop-type? te-hop-type
+--rw direction? te-link-direction
Figure 3: Generic Topology with overlay/underlay information
The advantages of using the underlay/overlay network profiled YANG
data model shown in Figure 3 as a core network topology model is to
have a common solutions for navigating between overlay/underlay
network topologies where:
* both the underlay and overlay network topologies are TE networks;
* both the underlay and overlay network topologies are non-TE
networks;
* the underlay and overlay network topologies are TE and non-TE
networks;
Busi, et al. Expires 23 April 2026 [Page 7]
Internet-Draft TE Topology Profiles October 2025
* the underlay or the overlay network topology is a multi-layer
network encompassing both TE and non-TE layers.
2.3.1. Supporting relationships in RFC8345
[RFC8345] defines the modeling constructs for supporting relations,
including supporting network (i.e. topology), supporting node,
supporting link, and supporting termination point. These relation
constructs facilitate network mappings and transformations. One use
case is to map a customized topology to a native topology. The
customized topology uses different name spaces from the native
topology when naming nodes, links, or termination points. There is a
supporting relationship between a modeling construct in the
customized topography to its counterpart in the native topology. In
such a relationship, the modeling constructs at both ends represent
the same type of network objects, which can be network (i.e.
topology), node, link, or termination point.
[RFC8795] defines the modeling constructs for network overlay and
underlay relations. When the network overlay technology is used,
some network objects (nodes or links) in the overlay network are
built on top of network objects in the underlay network. As a
result, the overlay-underlay relationship is created between network
objects in the overlay networks and other network objects in the
underlay network. Between the network object pairs in the overlay-
underlay relationship, the types of the network objects are usually
not the same. The network object can be a node in the overlay
network, while the related underlay network object is a topology in
the underlay network. A link in the overlay network can be related
to a path that consists of a sequence of nodes and links in the
underlay network.
2.4. Nodes with switching limitations
It is worth noting that a node, as defined in [RFC8345], does not
provide any information about the possible connectivity between its
TPs.
A node can have some switching limitations where connectivity is not
possible between all its TP pairs, for example when:
* the node represents a physical device with switching limitations;
* the node represents an abstraction of a network topology.
Busi, et al. Expires 23 April 2026 [Page 8]
Internet-Draft TE Topology Profiles October 2025
The following profile of the Topology YANG data model, defined in
[RFC8795], can be used for the management of nodes with switching
limitations by defining the node connectivity matrix to represent
feasible connections between termination points across the nodes:
module: ietf-te-topology
augment /nw:networks/nw:network/nw:network-types:
+--rw te-topology!
augment /nw:networks/nw:network/nw:node:
+--rw te-node-id? te-types:te-node-id
+--rw te!
+--rw te-node-attributes
+--rw connectivity-matrices
+--rw number-of-entries? uint16
+--rw is-allowed? boolean
+--rw connectivity-matrix* [id]
+--rw id uint32
+--rw from
| +--rw tp-ref? leafref
+--rw to
| +--rw tp-ref? leafref
+--rw is-allowed? boolean
Figure 4: Generic Topology with connectivity constraints
2.5. Multipoint links
According to Section 4.4.4 of [RFC8345], multipoint links can be
"represented through pseudonodes (similar to IS-IS, for example)".
Each access point can have different directionality with respect to
the multipoint link, as shown in Figure 5: - an access point of a
multipoint link can be able to both transmit and receive traffic:
this access point can be modelled as a TP (e.g., TP A in Figure 5)
terminating two links, one incoming link (e.g., Link 1 in Figure 5)
and one outgoing link (e.g., Link 2 in Figure 5); - an access point
of a multipoint link can be able only to receive traffic: this access
point can be modelled as a TP (e.g., TP B in Figure 5) with only one
incoming link (e.g., Link 3 in Figure 5); - an access point of a
multipoint link can be able only to transmit traffic: this access
point can be modelled as a TP (e.g., TP C in Figure 5) with only one
outgoing link (e.g., Link 4 in Figure 5).
Busi, et al. Expires 23 April 2026 [Page 9]
Internet-Draft TE Topology Profiles October 2025
|
| Link3
|
V
+-+
/ \
| B |
\ /
+--------+-+--------+
/ \
/ \
| |
| |
Link 1 | |
+-+ | | +-+
----->/ \| |/ \
| A | Psedonode | C |----->
<-----\ /| |\ /
+-+ | | +-+ Link 4
Link 2 | |
| |
| |
\ /
\ /
+-------------------+
Figure 5: Example of a pseudonode modelling a multipoint link
The switching limitations of the pseudonode, as defined in
Section 2.4, provides sufficient information to identify the type of
multipoint link: - in case of multipoint links, the connectivity
matrix of the pseudnode, reports that connectivity is enabled by
default between all the TPs of the node; - in case of point-to-
multipoint links, the connectivity matrix of the pseudnode, reports
that connectivity is possible only between the root TP and the leaf
TPs >> - if the point-to-multipoint link is bidirectional, the
connectivity matrix of the pseudonodes reports that connectivity is
possible from the root TP to the leaf TPs as well as from the leaf
TPs to the root TP; >> - the connectivity matrix of the psuedonode
can also describe point-to-multipoint links with more than one root
(also known as rooted-multipoint links), indicating also whether
connectivity between root TPs is allowed or not; - in case of hybrid
multipoint links, as defined in [I-D.ietf-nmop-simap-concept], the
connectivity matrix of the pseunode reports the list of TP pairs for
which connectivity is allowed or not allowed.
Busi, et al. Expires 23 April 2026 [Page 10]
Internet-Draft TE Topology Profiles October 2025
It is worth noting that the directionality of the access point of a
multipoint link overrides the switching limitations of the
pseudonode. For example, even if the connectivity matrix of the
psuedonode in Figure 5 indicates that connectivity is possible
between TP A and TP B, the traffic entering the pseudonode from TP A
cannot be transmitted by TP B since there is no outgoing link from TP
B.
Therefore, the connectivity matrix of a pseudonode modelling a point-
to-multipoint unidirectional link, does not need to report that
connectivity is only possible from the root TP to the leaf TPs but it
can report that connectivity is possible by default between all the
TPs of the node. The pseudonode represents a point-to-multipoint
unidirectional link, as indicated by a single root TP that can only
receive traffic and one or more leaf TPs that can only transmit
traffic.
|
| Link1
|
V
+-+
/ \
| A |
\ /
+--------+-+--------+
/ \
/ \
| |
| |
Link 2 | | Link 3
+-+ | | +-+
/ \| |/ \
<----| B | Psedonode | C |----->
\ /| |\ /
+-+ | | +-+
| |
| |
| |
\ /
\ /
+-------------------+
Figure 6: Example of a pseudonode modelling an undirectional
point-to- multipoint link
Busi, et al. Expires 23 April 2026 [Page 11]
Internet-Draft TE Topology Profiles October 2025
For example, Figure 6 shows an example of a pseudonode representing
an unidirectional point-to-multipoint link where the TP A is the root
TP and TPs B and C are the two leaf TPs.
3. Technology-specific augmentations
There are two main options to define technology-specific Topology
Models which can use the attributes defined in the Topology YANG data
model, defined in [RFC8795].
Both options are applicable to any possible profile of the TE
Topology Model, such as those defined in Section 2.
The first option is to define a technology-specific TE Topology Model
which augments the TE Topology Model, as shown in Figure 7:
+-------------------+
| Network Topology |
+-------------------+
^
|
| Augments
|
+-----------+-----------+
| TE Topology |
| (profile) |
+-----------------------+
^
|
| Augments
|
+----------+----------+
| Technology-Specific |
| TE Topology |
+---------------------+
Figure 7: Augmenting the TE Topology Model
This approach is more suitable for cases when the technology-specific
TE topology model provides augmentations to the TE Topology
constructs, such as bandwidth information (e.g., link bandwidth),
tunnel termination points (TTPs) or connectivity matrices. It also
allows providing augmentations to the Network Topology constructs,
such as nodes, links, and termination points (TPs).
This is the approach currently used in
[I-D.ietf-ccamp-eth-client-te-topo-yang] and
[I-D.ietf-ccamp-otn-topo-yang].
Busi, et al. Expires 23 April 2026 [Page 12]
Internet-Draft TE Topology Profiles October 2025
It is worth noting that a profile of the technology-specific TE
Topology model not using any TE topology attribute or constructs can
be used to address any use case that do not require these attributes.
In this case, only the 'te-topology' presence container of the TE
Topology Model needs to be implemented because it is the parent
container for the 'network-type' representing the technology-specific
topology model. Other data nodes defined in the TE Topology Model do
not need to be implemented by this profile.
The second option is to define a technology-specific Network Topology
Model which augments the Network Topology Model and to rely on the
multiple inheritance capability, which is implicit in the network-
types definition of [RFC8345], to allow using also the generic
attributes defined in the TE Topology model:
+-----------------------+
| Network Topology |
+-----------------------+
^ ^
| |
Augments +---+ +--+ Augments
| |
+---------+---+ +----------+----------+
| TE Topology | | Technology-specific |
| (profile) | | Network Topology |
+-------------+ +---------------------+
Figure 8: Augmenting the Network Topology Model with multi-
inheritance
This approach is more suitable in cases where the technology-specific
Network Topology Model provides augmentation only to the constructs
defined in the Network Topology Model, such as nodes, links, and
termination points (TPs). Therefore, with this approach, only the
generic attributes defined in the TE Topology Model could be used.
It is also worth noting that in this case, technology-specific
augmentations for the bandwidth information could not be defined.
In principle, it would be also possible to define both a technology
specific TE Topology Model which augments the TE Topology Model, and
a technology-specific Network Topology Model which augments the
Network Topology Model and to rely on the multiple inheritance
capability, as shown in Figure 9:
Busi, et al. Expires 23 April 2026 [Page 13]
Internet-Draft TE Topology Profiles October 2025
+-----------------------+
| Network Topology |
+-----------------------+
^ ^
| |
Augments +---+ +--+ Augments
| |
+---------+---+ +----------+----------+
| TE Topology | | Technology-specific |
| (profile) | | Network Topology |
+-------------+ +---------------------+
^ ^
| |
| Augments | References
| |
+----------+----------+ |
| Technology-Specific +--------------+
| TE Topology |
+---------------------+
Figure 9: Augmenting both the Network and TE Topology Models
This option does not provide any technical advantage with respect to
the first option, shown in Figure 7, but could be useful to add
augmentations to the TE Topology constructs and to re-use an already
existing technology-specific Network Topology Model.
It is worth noting that the technology-specific TE Topology model can
reference constructs defined by the technology-specific Network
Topology model but it could not augment constructs defined by the
technology-specific Network Topology model.
3.1. Multi-inheritance
As described in section 4.1 of [RFC8345], the network types should be
defined using presence containers to allow the representation of
network subtypes.
The hierarchy of network subtypes can be single hierarchy, as shown
in Figure 7. In this case, each presence container contains at most
one child presence container, as shows in the JSON code below:
Busi, et al. Expires 23 April 2026 [Page 14]
Internet-Draft TE Topology Profiles October 2025
{
"ietf-network:ietf-network": {
"ietf-te-topology:te-topology": {
"example-te-topology": {}
}
}
}
The hierarchy of network subtypes can also be multi-hierarchy, as
shown in Figure 8 and Figure 9. In this case, one presence container
can contain more than one child presence containers, as show in the
JSON codes below:
{
"ietf-network:ietf-network": {
"ietf-te-topology:te-topology": {}
"example-network-topology": {}
}
}
{
"ietf-network:ietf-network": {
"ietf-te-topology:te-topology": {
"example-te-topology": {}
}
"example-network-topology": {}
}
}
Other examples of multi-hierarchy topologies are described in
[I-D.ietf-teas-yang-sr-te-topo].
3.2. Example (Link augmentation)
This section provides an example on how technology-specific
attributes can be added to the Link construct:
Busi, et al. Expires 23 April 2026 [Page 15]
Internet-Draft TE Topology Profiles October 2025
+--rw link* [link-id]
+--rw link-id link-id
+--rw source
| +--rw source-node? -> ../../../nw:node/node-id
| +--rw source-tp? leafref
+--rw destination
| +--rw dest-node? -> ../../../nw:node/node-id
| +--rw dest-tp? leafref
+--rw supporting-link* [network-ref link-ref]
| +--rw network-ref
| | -> ../../../nw:supporting-network/network-ref
| +--rw link-ref leafref
+--rw example-link-attributes
| <...>
+--rw te!
+--rw te-link-attributes
+--rw name? string
+--rw example-te-link-attributes
| <...>
+--rw max-link-bandwidth
+--rw te-bandwidth
+--rw (technology)?
+--:(generic)
| +--rw generic? te-bandwidth
+--:(example)
+--rw example? example-bandwidth
Figure 10: Augmenting the Link with technology-specific attributes
The technology-specific attributes within the example-link-attributes
container can be defined either in the technology-specific TE
Topology Model (Option 1) or in the technology-specific Network
Topology Model (Option 2 or Option 3). These attributes can only be
non-TE and do not require the implementation of the te container.
The technology-specific attributes within the example-te-link-
attributes container as well as the example max-link-bandwidth can
only be defined in the technology-specific TE Topology Model (Option
1 or Option 3). These attributes can be TE or non-TE and require the
implementation of the te container.
4. Open Issues
4.1. Implemented profiles
When a server implements a profile of the TE topology model, there is
no standardized mechanism for the server to report to the client the
subset of the model being implemented.
Busi, et al. Expires 23 April 2026 [Page 16]
Internet-Draft TE Topology Profiles October 2025
This might not be an issue in case the TE topology profile is read by
the the client because the server reports in the operational
datastore only the leaves which have been implemented, as described
in section 5.3 of [RFC8342].
More investigation is instead required in case the TE topology
profile is configured by the client, to avoid that the client tries
to write an attribute not used in the TE Topology profile implemented
by the server.
It is also worth noting that the supported profile may also depend on
other attributes (for example the network type), so the YANG
deviation mechanism is not applicable to this scenario.
Note: that this issue is also tracked in github as issue #161.
5. Security Considerations
This document provides only information about how the Topology YANG
data model, defined in [RFC8795], can be profiled to address some
scenarios which are not considered as TE.
As such, this document does not introduce any additional security
considerations besides those already defined in [RFC8795].
6. IANA Considerations
This document requires no IANA actions.
Acknowledgments
The authors would like to thank Vishnu Pavan Beeram, Daniele
Ceccarelli, Jonas Ahlberg and Scott Mansfield for providing useful
suggestions for this draft.
This document was prepared using kramdown.
Initial versions of this document were prepared using 2-Word-
v2.0.template.dot.
References
Normative References
[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>.
Busi, et al. Expires 23 April 2026 [Page 17]
Internet-Draft TE Topology Profiles October 2025
[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>.
[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>.
Informative References
[I-D.ietf-ccamp-eth-client-te-topo-yang]
Yu, C., Zheng, H., Guo, A., Busi, I., Xu, Y., Zhao, Y.,
and X. Liu, "A YANG Data Model for Ethernet TE Topology",
Work in Progress, Internet-Draft, draft-ietf-ccamp-eth-
client-te-topo-yang-10, 15 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
eth-client-te-topo-yang-10>.
[I-D.ietf-ccamp-otn-topo-yang]
Zheng, H., Busi, I., Liu, X., Belotti, S., and O. G. de
Dios, "A YANG Data Model for Optical Transport Network
Topology", Work in Progress, Internet-Draft, draft-ietf-
ccamp-otn-topo-yang-20, 7 November 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
otn-topo-yang-20>.
[I-D.ietf-ccamp-transport-nbi-app-statement]
Busi, I., King, D., Zheng, H., and Y. Xu, "Transport
Northbound Interface Applicability Statement", Work in
Progress, Internet-Draft, draft-ietf-ccamp-transport-nbi-
app-statement-17, 10 July 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-ccamp-
transport-nbi-app-statement-17>.
[I-D.ietf-nmop-simap-concept]
Havel, O., Claise, B., de Dios, O. G., and T. Graf,
"SIMAP: Concept, Requirements, and Use Cases", Work in
Progress, Internet-Draft, draft-ietf-nmop-simap-concept-
07, 18 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-nmop-
simap-concept-07>.
[I-D.ietf-teas-rfc3272bis]
Farrel, A., "Overview and Principles of Internet Traffic
Engineering", Work in Progress, Internet-Draft, draft-
Busi, et al. Expires 23 April 2026 [Page 18]
Internet-Draft TE Topology Profiles October 2025
ietf-teas-rfc3272bis-27, 12 August 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
rfc3272bis-27>.
[I-D.ietf-teas-yang-sr-te-topo]
Liu, X., Bryskin, I., Beeram, V. P., Saad, T., Shah, H.,
and S. Litkowski, "YANG Data Model for SR and SR TE
Topologies on MPLS Data Plane", Work in Progress,
Internet-Draft, draft-ietf-teas-yang-sr-te-topo-19, 4 July
2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
teas-yang-sr-te-topo-19>.
Contributors
Aihua Guo
Futurewei Inc.
Email: aihuaguo.ietf@gmail.com
Haomian Zheng
Huawei
Email: zhenghaomian@huawei.com
Sergio Belotti
Nokia
Email: sergio.belotti@nokia.com
Authors' Addresses
Italo Busi
Huawei
Email: italo.busi@huawei.com
Xufeng Liu
Alef Edge
Email: xufeng.liu.ietf@gmail.com
Igor Bryskin
Individual
Email: i_bryskin@yahoo.com
Tarek Saad
Cisco Systems Inc
Busi, et al. Expires 23 April 2026 [Page 19]
Internet-Draft TE Topology Profiles October 2025
Email: tsaad.net@gmail.com
Oscar Gonzalez de Dios
Telefonica
Email: oscar.gonzalezdedios@telefonica.com
Busi, et al. Expires 23 April 2026 [Page 20]