Path Energy Traffic Ratio API (PETRA)
draft-petra-green-api-03
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Alberto Rodriguez-Natal , Luis M. Contreras , Marisol Palmero , Jan Lindblad , Adrián Gallego Sánchez | ||
| Last updated | 2026-03-02 | ||
| Replaces | draft-petra-path-energy-api | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
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| Yang Validation | 0 errors, 0 warnings | ||
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| Send notices to | (None) |
draft-petra-green-api-03
GREEN A. Rodriguez-Natal
Internet-Draft Cisco
Intended status: Informational L. M. Contreras
Expires: 3 September 2026 Telefonica
M. Palmero
Independent Consultant
J. Lindblad
All For Eco
A. Gallego Sanchez
T-SYSTEMS
2 March 2026
Path Energy Traffic Ratio API (PETRA)
draft-petra-green-api-03
Abstract
This document describes an API to query a network regarding its
Energy Traffic Ratio for a given path.
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 3 September 2026.
Copyright Notice
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
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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. Terminology and Requirements Notation . . . . . . . . . . . . 3
3. Path Energy Traffic Ratio API (PETRA) . . . . . . . . . . . . 3
3.1. Energy Information . . . . . . . . . . . . . . . . . . . 3
3.2. Recursive Usage . . . . . . . . . . . . . . . . . . . . . 4
4. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Module Structure . . . . . . . . . . . . . . . . . . . . 6
4.2. Module Definition . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. Use Cases . . . . . . . . . . . . . . . . . . . . . 12
A.1. SD-WAN . . . . . . . . . . . . . . . . . . . . . . . . . 12
A.2. Multilayer Energy Management . . . . . . . . . . . . . . 13
A.3. SLA Negotiation for Energy-Efficient Services . . . . . . 13
Appendix B. Requirements for Energy Efficiency Management . . . 14
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
Energy management is becoming one of the major societal goals for the
next decade, and networks are one of the major consumers of energy
nowadays. Energy management of network services is thus one of the
forefronts of innovation and action from network service
stakeholders, involving manufacturers, operators and customers. In
this line, there is a shared goal of achieving better energy
awareness.
As with any other network metric, the energy traffic ratio could be
collected from the underlying network infrastructure. However, there
is not a common or single definition of energy metrics towards
network consumers so that can be uniformly reported, particularly in
heterogeneous network scenarios. This document introduces an API to
query networks about Energy Traffic Ratio.
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2. Terminology and Requirements Notation
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.
3. Path Energy Traffic Ratio API (PETRA)
This documents describes an API to query a network about the Energy
Traffic Ratio for a given path. It takes as input the source and
destination of a path along with the traffic throughput between and
returns energy information related to the traffic on the path. This
is energy computed by the infrastructure that is dynamically part of
the traffic path. The API is agnostic to the actual hops and
underlaying infrastructure that enables a path, which might change
transparently to the API. This document only describes the API, the
computation of the energy information to return is out of the scope
of this document. While the current version of this document assumes
source and destination as IP addresses, future version of this
document might consider other options as well.
3.1. Energy Information
This API allows to return a number of energy attributes associated
with the path and the traffic. Currently the parameters that could
be returned as energy information as part of the query are:
* Watts per Gigabit: How many Watts are consumed per Gigabit of
traffic traversing the path.
Some other parameters that could be considered as well as part of the
energy information include:
* Renewable Percentage: How much of the energy consumed comes from
renewable energy sources.
* Carbon Intensity: How much carbon emissions are generated as a
consequence of the energy consumed.
* ...
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3.2. Recursive Usage
The API is envisioned in such a way that could be used recursively.
That means, subpaths could report their energy consumption using
PETRA and such energy consumption could be aggregated and reported
for the overall path also using PETRA.
Similarly, this API could be (recursively) used to provide energy
information according to the definition of Service Models in an SDN
context as described in [RFC8309]. In that case, using Figure 3 in
[RFC8309] as reference (below), PETRA could be used between the
Controller(s) and the Network Orchestrator(s), between the Network
Orchestrator(s) and the Service Orchestrator, and between the Service
Orchestrator and the Customer(s).
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Customer
------------------ Service ----------
| | Model | |
PETRA as | Service |<-------->| Customer |
Customer Service | Orchestrator | (a) | |
related API | | ----------
------------------
. .
########################## . . (b) -----------
. (b) . ......|Application|
. . : | BSS/OSS |
PETRA as . . : -----------
Service related API . Service Delivery . :
. Model . :
------------------ ------------------
| | | |
############# | Network | | Network |
| Orchestrator | | Orchestrator |
| | | |
.------------------ ------------------.
PETRA as . : : .
Network API . : Network Configuration : .
. : Model : .
------------ ------------ ------------ ------------
| | | | | | | |
### | Controller | | Controller | | Controller | | Controller |
| | | | | | | |
------------ ------------ ------------ ------------
: . . : :
: . . Device : :
: . . Configuration : :
: . . Model : :
--------- --------- --------- --------- ---------
| Network | | Network | | Network | | Network | | Network |
| Element | | Element | | Element | | Element | | Element |
--------- --------- --------- --------- ---------
While considering recursive usage, the aspect of double-counting
shall also be taken into consideration. Double counting refers to
the fact of counting more than once the same energy consumed.
Organizations using PETRA in a recursive manner need to take
appropriate measures to ensure no double-counting occurs across
recursive calls to the API.
4. YANG Module
This is a posible definition of PETRA as a module following the YANG
specification [RFC6020].
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4.1. Module Structure
This section uses the graphical representation of data models defined
in [RFC8340].
module: ietf-petra
+--rw energy
+---x query
+---w input
| +---w src-ip ietf-inet-types:ip-address
| +---w dst-ip ietf-inet-types:ip-address
| +---w throughput decimal64
+--ro output
+--ro (result)?
+--:(success)
| +--ro success
| +--ro watts-per-gigabit? decimal64
| +--ro data-source-accuracy? identityref
+--:(invalid-address)
+--ro invalid-address
4.2. Module Definition
<CODE BEGINS> file "ietf-petra@2024-07-05.yang"
module ietf-petra {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-petra";
prefix ietf-petra;
import ietf-inet-types {
prefix ietf-inet-types;
}
import ietf-power-and-energy {
prefix eo;
reference "draft-bcmj-green-power-and-energy-yang";
}
organization
"IETF GREEN Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/green/>
WG List: <mailto:green@ietf.org>";
description
"Initial YANG rendition of the PETRA Energy API, v1.0.1
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Copyright (c) 2025 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to
the license terms contained in, the Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.
";
/*
If you have an implementation of this YANG module, you could
access it like something this over RESTCONF:
$ curl --location --request POST \
'https://localhost:8008/restconf/operations/energy/query' \
--header 'Content-Type: application/yang-data+json' \
--user 'admin:admin' \
--data-raw '{
'input' : {
'src-ip': '10.10.10.10',
'dst-ip': '10.20.20.20',
'throughput': '40'
}
}'
And if all goes well, you might receive (besides all the
HTTP headers) a reply body with something like this:
{
'output': {
'success': {
'watts-per-gigabit': '191.855'
}
}
}
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*/
revision 2025-05-12 {
description
"Initial YANG rendition of the PETRA Energy API, v1.0.1";
reference
"RFC XXXX: ...";
}
grouping energy-metrics-g {
description
"Grouping for query result metrics.";
leaf watts-per-gigabit {
type decimal64 {
fraction-digits 3;
}
units W/Gb;
description
"Watts consumed per Gigabit transmitted";
}
leaf data-source-accuracy {
type identityref { base eo:data-source-accuracy; }
description
"Accuracy classification of the watts-per-gigabit value,
using the GREEN data-source-accuracy hierarchy.
Implementations SHOULD populate this leaf to enable
consumers to assess reliability. For path-aggregated
values derived from multiple components, the RECOMMENDED
value is the LEAST accurate accuracy class among all
contributing energy objects.";
}
}
container energy {
description
"PETRA API top level container.";
action query {
description
"Query the network for energy consupmtion";
input {
leaf src-ip {
type ietf-inet-types:ip-address;
mandatory true;
description
"Source IP address";
}
leaf dst-ip {
type ietf-inet-types:ip-address;
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mandatory true;
description
"Destination IP address";
}
leaf throughput {
type decimal64 {
fraction-digits 3;
}
units Gb/s;
mandatory true;
description
"Throughput between source and destination
(in gigabits per second)";
}
}
output {
choice result {
description
"Choice of which kind of result the query gave.";
container success {
description
"Successful operation";
uses energy-metrics-g;
}
container invalid-address {
description
"Invalid source/destination IP address supplied";
}
}
}
}
}
}
<CODE ENDS>
5. Security Considerations
In order to mitigate security risks, the PETRA API should implement
the necessary mechanisms for authentication, secure data transfer and
privacy preservation. On the other hand, in order to prevent denial
of service attacks, new subsequent similar requests could be silently
ignored during periods of time, or even requests from the same client
could be filtered to prevent system (i.e., controller or
orchestrator) affection.
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6. Acknowledgments
Kudos to Elis Lulja for his help with the OpenAPI specification in
early versions of this draft. Thanks to Fernando Sanz Garcia and
Lori Jakab for their help and support on this work.
The contribution of Telefonica to this document has been supported by
the Smart Networks and Services Joint Undertaking (SNS JU) under the
European Union's Horizon Europe research and innovation projects
6Green (Grant Agreement no. 101096925) and Exigence (Grant Agreement
no. 101139120). The contribution of A. Gallego Sánchez to this
document has been partially supported by the Smart Networks and
Services Joint Undertaking (SNS JU) under the European Union's
Horizon Europe research and innovation project Sustain6G (Grant
Agreement no. 101191936).
7. IANA Considerations
The IANA is requested to as assign a new namespace URI from the IETF
XML registry.
This document registers the following namesace URIs in the IETF XML
registry [RFC3688]:
--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-petra
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
--------------------------------------------------------------------
This document registers the following YANG modules in the "YANG
Module Names" registry [RFC6020]:
--------------------------------------------------------------------
Name: ietf-petra
Namespace: urn:ietf:params:xml:ns:yang:ietf-petra
Prefix: petra
Reference: RFC XXX
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--------------------------------------------------------------------
8. References
8.1. Normative References
[I-D.belmq-green-framework]
Claise, B., Contreras, L. M., Lindblad, J., Palmero, M.
P., Stephan, E., and Q. Wu, "Framework for Energy
Efficiency Management", Work in Progress, Internet-Draft,
draft-belmq-green-framework-10, 8 February 2026,
<https://datatracker.ietf.org/doc/html/draft-belmq-green-
framework-10>.
[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/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[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/info/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/info/rfc6242>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
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[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/info/rfc8174>.
[RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models
Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
<https://www.rfc-editor.org/info/rfc8309>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
8.2. Informative References
[I-D.bcmj-green-power-and-energy-yang]
Claise, B., Chen, G., Palmero, M. P., and J. Lindblad,
"Power and Energy YANG Module", Work in Progress,
Internet-Draft, draft-bcmj-green-power-and-energy-yang-04,
2 March 2026, <https://datatracker.ietf.org/doc/html/
draft-bcmj-green-power-and-energy-yang-04>.
Appendix A. Use Cases
This section describes some use-cases where this specification might
be useful.
A.1. SD-WAN
Software-Defined Wide-Area Networks (SD-WAN) have become a common way
for enterprises to provide cost-effective connectivity across their
different geographically distributed sites. Typically, SD-WAN
deployments operate as an overlay network that is established on top
of an existing underlay connectivity network. One aspect to consider
is that in many SD-WAN production deployments the operator of the
overlay network and the operator of the underlay network are
different organizations.
This poses an additional challenge when trying to derive energy
metrics. Even if the underlay network is instrumented to collect
energy data, this data is opaque to the operator of the overlay
network which has no access to underlay information. While operators
of underlay networks offer certain general network metrics to overlay
operators, no interface has been defined to allow the overlay
operator to query the underlay network for energy information.
In this context, the PETRA specification presented in this document
enables the operator of the SD-WAN network to coordinate with the
underlay operator to capture energy data. This in turns opens
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further use-cases, from observability and reporting to potentially
overlay policies based on underlay energy data, further enabling an
overall more energy-efficient operation of the network.
In addition to energy considerations in SD-WAN deployments, PETRA can
also be leveraged for broader energy-aware service routing. In this
context, network controllers and service orchestrators, such as SD-
WAN controllers, transport SDN controllers, 5G slice orchestrators,
or multi-domain service orchestrators, can use PETRA metrics not only
to balance latency, throughput, or load, but also to optimize path
selection according to energy-efficiency objectives. For example,
paths with the lowest energy-consumption could be preferred, enabling
service differentiation where energy-efficient paths are explicitly
prioritized. This extends the SD-WAN use case into a more general
paradigm where routing decisions are jointly driven by network
performance and energy impact.
A.2. Multilayer Energy Management
The concept of multilayer L3-L1 collection involves integrating data
from different network layers to provide a comprehensive view of
network operations. The use case of multilayer involves collecting
and correlating data from Layer 3 (network layer) down to Layer 1
(physical layer). This multilayer approach allows for better network
performance, optimization, and troubleshooting by providing end-to-
end visibility.
Leveraging PETRA API for multilayer L3-L1 collection use case
enhances energy management by providing comprehensive visibility,
enabling optimization, and supporting proactive management. This
makes PETRA a useful tool for more accurate, efficient and effective
energy management in modern networks.
A.3. SLA Negotiation for Energy-Efficient Services
Another use case for PETRA could the negotiation of Service Level
Agreements (SLAs) between operators and enterprise customers. By
exposing PETRA-derived metrics such as energy consumption, renewable
energy percentage, providers can offer differentiated SLAs that
explicitly include environmental targets. This enables customers to
select network services not only based on performance guarantees
(e.g. latency), but also on their environmental footprint (or a
combination of both). For example requesting that at least 60% of
traffic be carried over renewable-powered infrastructure. Such SLAs
empower customers to align their digital services with corporate
energy-efficient and sustainability goals and reporting requirements,
while operators can use PETRA as the trusted source of verifiable
energy data.
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Appendix B. Requirements for Energy Efficiency Management
The document Framework for Energy Efficiency Management
[I-D.belmq-green-framework] describes a reference model for energy
management. The model includes an 'API Service Interface', labeled
as interface (g) in the document, which "enables access for service
consumption, enabling data retrieval, control, and integration
through API".
In that context, PETRA is one example of such 'API Service
Interface'. In the particular case of PETRA, the API might be used
to consume from the Network controller, the Domain controller, or
both. Appendix A describes a few use-cases that could make use of
PETRA as an 'API Service Interface' within the Framework for Energy
Efficiency Management [I-D.belmq-green-framework].
Contributors
Fernando Munoz
Cisco
Madrid
Spain
Email: fmunozma@cisco.com
Alejandro Muniz
Madrid
Spain
Roland Schott
Deutsche Telekom
Deutsche-Telekom-Allee 9
64295 Darmstadt
Germany
Email: Roland.Schott@telekom.de
Authors' Addresses
Alberto Rodriguez-Natal
Cisco
Barcelona
Spain
Email: natal@cisco.com
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Luis M. Contreras
Telefonica
Madrid
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
Marisol Palmero
Independent Consultant
Spain
Email: marisol.ietf@gmail.com
Jan Lindblad
All For Eco
Email: jan.lindblad+ietf@for.eco
Adrian Gallego Sanchez
T-SYSTEMS
Madrid
Spain
Email: ADRIAN.GALLEGO-SANCHEZ@t-systems.com
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