Internet Engineering Task Force (IETF) G. Mirsky

Internet Engineering Task Force (IETF) G. Mirsky
Request for Comments: 9551 Ericsson
Category: Informational F. Theoleyre
ISSN: 2070-1721 CNRS
G. Papadopoulos
IMT Atlantique
CJ. Bernardos
UC3M
B. Varga
J. Farkas
Ericsson
March 2024

Framework of Operations, Administration, and Maintenance (OAM) for
Deterministic Networking (DetNet)

Abstract

Deterministic Networking (DetNet), as defined in RFC 8655, aims to
provide bounded end-to-end latency on top of the network
infrastructure, comprising both Layer 2 bridged and Layer 3 routed
segments. This document's primary purpose is to detail the specific
requirements of the Operations, Administration, and Maintenance (OAM)
recommended to maintain a deterministic network. The document will
be used in future work that defines the applicability of and
extension of OAM protocols for a deterministic network. With the
implementation of the OAM framework in DetNet, an operator will have
a real-time view of the network infrastructure regarding the
network's ability to respect the Service Level Objective (SLO), such
as packet delay, delay variation, and packet-loss ratio, assigned to
each DetNet flow.

Status of This Memo

This document is not an Internet Standards Track specification; it is
published for informational purposes.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are candidates for any level of Internet
Standard; see Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9551.

Copyright Notice

Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.

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Table of Contents

1. Introduction
1.1. Definitions
1.2. Requirements Language
2. Role of OAM in DetNet
3. Operation
3.1. Information Collection
3.2. Continuity Check
3.3. Connectivity Verification
3.4. Route Tracing
3.5. Fault Verification/Detection
3.6. Fault Localization and Characterization
3.7. Use of Hybrid OAM in DetNet
4. Administration
4.1. Collection of Metrics
4.2. Worst-Case Metrics
5. Maintenance
5.1. Replication/Elimination
5.2. Resource Reservation
6. Requirements
6.1. For the DetNet Forwarding Sub-layer
6.2. For the DetNet Service Sub-layer
7. IANA Considerations
8. Security Considerations
9. Privacy Considerations
10. References
10.1. Normative References
10.2. Informative References
Acknowledgments
Authors' Addresses

1. Introduction

Deterministic Networking (DetNet) [RFC8655] has proposed to provide a
bounded end-to-end latency on top of the network infrastructure,
comprising both Layer 2 bridged and Layer 3 routed segments. That
work encompasses the data plane, OAM, time synchronization,
management, control, and security aspects.

Operations, Administration, and Maintenance (OAM) tools are of
primary importance for IP networks [RFC7276]. DetNet OAM should
provide a toolset for fault detection, localization, and performance
measurement.

This document's primary purpose is to detail the specific
requirements of the OAM features recommended to maintain a
deterministic/reliable network. Specifically, it investigates the
requirements for a deterministic network that supports critical
flows.

In this document, the term "OAM" will be used according to its
definition specified in [RFC6291]. DetNet is expected to implement
an OAM framework to maintain a real-time view of the network
infrastructure, and its ability to respect the Service Level
Objectives (SLOs), such as in-order packet delivery, packet delay,
delay variation, and packet-loss ratio, assigned to each DetNet flow.

This document lists the OAM functional requirements for a DetNet
domain. The list can further be used for gap analysis of available
OAM tools to identify:

* possible enhancements of existing tools, or

* whether new OAM tools are required to support proactive and on-
demand path monitoring and service validation.

1.1. Definitions

This document uses definitions, particularly of a DetNet flow,
provided in Section 2.1 of [RFC8655]. The following terms are used
throughout this document as defined below:

DetNet OAM domain: a DetNet network used by the monitored DetNet
flow. A DetNet OAM domain (also referred to in this document as
"OAM domain") may have Maintenance End Points (MEPs) on its edge
and Maintenance Intermediate Points (MIPs) within.

DetNet OAM instance: a function that monitors a DetNet flow for
defects and/or measures its performance metrics. Within this
document, the shorter version "OAM instance" is used
interchangeably.

Maintenance End Point (MEP): an OAM instance that is capable of
generating OAM test packets in the particular sub-layer of the
DetNet OAM domain.

Maintenance Intermediate Point (MIP): an OAM instance along the
DetNet flow in the particular sub-layer of the DetNet OAM domain.
An active MIP MUST respond to an OAM message generated by the MEP
at its sub-layer of the same DetNet OAM domain.

Control and management plane: the control and management planes are
used to configure and control the network. Relative to a DetNet
flow, the control and/or management plane can be out of band.

Active measurement methods: (as defined in [RFC7799]) these methods
modify a DetNet flow by injecting specially constructed test
packets [RFC2544].

Passive measurement methods: (as defined in [RFC7799]) these methods
infer information by observing unmodified existing flows.

Hybrid measurement methods: (as defined in [RFC7799]) the
combination of elements of both active and passive measurement
methods.

In-band OAM: an active OAM method that is in band within the
monitored DetNet OAM domain when it traverses the same set of
links and interfaces receiving the same QoS and Packet
Replication, Elimination, and Ordering Functions (PREOF) treatment
as the monitored DetNet flow.

Out-of-band OAM: an active OAM method whose path through the DetNet
domain may not be topologically identical to the path of the
monitored DetNet flow, its test packets may receive different QoS
and/or PREOF treatment, or both.

On-path telemetry: on-path telemetry can be realized as a hybrid OAM
method. The origination of the telemetry information is
inherently in band as packets in a DetNet flow are used as
triggers. Collection of the on-path telemetry information can be
performed using in-band or out-of-band OAM methods.

1.2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. The requirements language is used in
Sections 1.1 and 6, and applies to the implementations of DetNet OAM.

2. Role of OAM in DetNet

DetNet networks are expected to provide communications with
predictable low packet delay, packet loss, and packet misordering.
Most critical applications will define a set of SLOs to be required
for the DetNet flows they generate.

To respect strict guarantees, DetNet can use an orchestrator able to
monitor and maintain the network. Typically, a Software-Defined
Network (SDN) controller places DetNet flows in the deployed network
based on their SLOs. Thus, resources have to be provisioned a priori
for the regular operation of the network.

Most of the existing OAM tools can be used in DetNet networks, but
they can only cover some aspects of deterministic networking.
Fulfilling strict guarantees is essential for DetNet flows, resulting
in new DetNet-specific functionalities that must be covered with OAM.
Filling these gaps is inevitable and needs accurate consideration of
DetNet specifics. Similar to DetNet flows, their OAM also needs
careful end-to-end engineering.

For example, appropriate placing of MEPs along the path of a DetNet
flow is not always a trivial task and may require proper design
together with the design of the service component of a given DetNet
flow.

There are several DetNet-specific challenges for OAM. Bounded
network characteristics (e.g., delay, loss) are inseparable service
parameters; therefore, Performance Monitoring (PM) OAM is a key topic
for DetNet. OAM tools are needed to monitor each SLO without
impacting the DetNet flow characteristics. A further challenge is
strict resource allocation. Resources used by OAM must be considered
and allocated to avoid disturbing DetNet flows.

The DetNet Working Group has defined two sub-layers:

The DetNet service sub-layer at which a DetNet service (e.g.,
service protection) is provided.

The DetNet forwarding sub-layer, which optionally provides
resource allocation for DetNet flows over paths provided by the
underlying network.

OAM mechanisms exist for the DetNet forwarding sub-layer, but the
service sub-layer requires new OAM procedures. These new OAM
functions must allow, for example, recognizing/discovering DetNet
relay nodes, getting information about their configuration, and
checking their operation or status.

DetNet service sub-layer functions use a sequence number for PREOF,
which creates a challenge for inserting OAM packets in the DetNet
flow.

Fault tolerance also assumes that multiple paths could be provisioned
to maintain an end-to-end circuit by adapting to the existing
conditions. The DetNet Controller Plane, e.g., central controller/
orchestrator, controls the PREOF on a node. OAM is expected to
support monitoring and troubleshooting PREOF on a particular node and
within the domain.

Note that a distributed architecture of the DetNet Control Plane can
also control PREOF in those scenarios where DetNet solutions involve
more than one single central controller.

The DetNet forwarding sub-layer is based on preexisting technologies
and has much better coverage regarding OAM. However, the forwarding
sub-layer is terminated at DetNet relay nodes, so the end-to-end OAM
state of forwarding may be created only based on the status of
multiple forwarding sub-layer segments serving a given DetNet flow
(e.g., in case of DetNet MPLS, there may be no end-to-end LSP below
the DetNet pseudowire).

3. Operation

OAM features will enable DetNet with robust operation both for
forwarding and routing purposes.

It is worth noting that the test and data packets are expected to
follow the same path, i.e., connectivity verification has to be
conducted in band without impacting data traffic. It is expected
that test packets share fate with the monitored data traffic without
introducing congestion in normal network conditions.

3.1. Information Collection

Information about the state of the network can be collected using
several mechanisms. Some protocols, e.g., the Simple Network
Management Protocol (SNMP), poll for updated data. Other protocols,
such as YANG-Push [RFC8641], can be used to set up subscriptions for
the data defined in the YANG data models to be published periodically
or when the underlying data changes. Either way, information is
collected and sent using the DetNet Controller Plane.

Also, we can characterize methods of transporting OAM information
relative to the path of data. For instance, OAM information may be
transported in band or out of band relative to the DetNet flow. In
the case of the former, the telemetry information uses resources
allocated for the monitored DetNet flow. If an in-band method of
transporting telemetry is used, the amount of generated information
needs to be carefully analyzed, and additional resources must be
reserved. [RFC9197] defines the in-band transport mechanism where
telemetry information is collected in the data packet on which
information is generated. Two tracing methods are described:

* end-to-end, i.e., from the ingress and egress nodes, and

* hop-by-hop, i.e., like end-to-end with additional information from
transit nodes.

[RFC9326] and [HYBRID-TWO-STEP] are examples of out-of-band telemetry
transport. In the former case, information is transported by each
node traversed by the data packet of the monitored DetNet flow in a
specially constructed packet. In the latter, information is
collected in a sequence of follow-up packets that traverse the same
path as the data packet of the monitored DetNet flow. In both
methods, transport of the telemetry can avoid using resources
allocated for the DetNet domain.

3.2. Continuity Check

A continuity check is used to monitor the continuity of a path, i.e.,
that there exists a way to deliver packets between MEP A and MEP B.
The continuity check detects a network failure in one direction: from
the MEP transmitting test packets to the remote egress MEP. The
continuity check in a DetNet OAM domain monitors the DetNet
forwarding sub-layer; thus, it is not affected by a PREOF that
operates at the DetNet service sub-layer ([RFC8655]).

3.3. Connectivity Verification

In addition to the Continuity Check, DetNet solutions have to verify
connectivity. This verification considers an additional constraint:
the absence of misconnection. The misconnection error state is
entered after several consecutive test packets from other DetNet
flows are received. The definition of the conditions for entry and
exit of a misconnection error state is outside the scope of this
document. Connectivity verification in a DetNet OAM domain monitors
the DetNet forwarding sub-layer; thus, it is not affected by PREOF
that operates at the DetNet service sub-layer ([RFC8655]).

3.4. Route Tracing

Ping and traceroute are two ubiquitous tools that help localize and
characterize a failure in the network using an echo request/reply
mechanism. They help to identify a subset of the routers in the
path. However, to be predictable, resources are reserved per flow in
DetNet. Thus, DetNet needs to define route tracing tools able to
trace the route for a specific flow. Also, tracing can be used for
the discovery of the Path Maximum Transmission Unit (PMTU) or
location of elements of PREOF for the particular route in the DetNet
domain.

DetNet is not expected to use Equal-Cost Multipath (ECMP) [RFC8939].
As a result, DetNet OAM in an ECMP environment is outside the scope
of this document.

3.5. Fault Verification/Detection

DetNet expects to operate fault-tolerant networks. Thus, mechanisms
able to detect faults before they impact network performance are
needed.

The network has to detect when a fault has occurred, i.e., the
network has deviated from its expected behavior. Fault detection can
be based on proactive OAM protocols like continuity check or on-
demand methods like ping. While the network must report an alarm,
the cause may not be identified precisely. Examples of such alarms
are significant degradation of the end-to-end reliability or when a
buffer overflow occurs.

3.6. Fault Localization and Characterization

The ability to localize a network defect and provide its
characterization are necessary elements of network operation.

Fault localization: a process of deducing the location of a network
failure from a set of observed failure indications. For example,
this might be achieved by tracing the route of the DetNet flow in
which the network failure was detected. Another method of fault
localization can correlate reports of failures from a set of
interleaved sessions monitoring path continuity.

Fault characterization: a process of identifying the root cause of
the problem. For instance, misconfiguration or malfunction of
PREOF elements can be the cause of erroneous packet replication or
extra packets being flooded in the DetNet domain.

3.7. Use of Hybrid OAM in DetNet

Hybrid OAM methods are used in performance monitoring and defined in
[RFC7799] as follows:

| Hybrid Methods are Methods of Measurement that use a combination
| of Active Methods and Passive Methods.

A hybrid measurement method can produce metrics as close to measured
using a passive measurement method. The passive methods measure
metrics closest to the network's actual conditions. A hybrid method,
even if it alters something in a data packet, even if that is as
little as the value of a designated field in the packet
encapsulation, is considered an approximation of a passive
measurement method. One example of such a hybrid measurement method
is the Alternate-Marking Method (AMM) described in [RFC9341]. As
with all on-path telemetry methods, AMM in a DetNet domain with the
IP data plane is, by design, in band with respect to the monitored
DetNet flow. Because the marking is applied to a data flow, measured
metrics are directly applicable to the DetNet flow. AMM minimizes
the additional load on the DetNet domain by using nodal collection
and computation of performance metrics optionally in combination with
using out-of-band telemetry collection for further network analysis.

4. Administration

The ability to expose a collection of metrics to support an
operator's decision-making is essential. The following performance
metrics are useful:

Queuing Delay: the time elapsed between enqueuing a packet and its
transmission to the next hop.

Buffer occupancy: the number of packets present in the buffer for
each of the existing flows.

Per DetNet flow: a metric reflecting end-to-end performance for a
given flow. Each of the paths has to be isolated in a multipath
routing environment.

Per-path: detection of a misbehaving path or paths when multiple
paths are used for the service protection.

Per-device: detection of a misbehaving device.

4.1. Collection of Metrics

It is important to optimize the volume and frequency of statistics/
measurement collection, whether the mechanisms are distributed,
centralized, or both. Periodic and event-triggered collection
information characterizing the state of a network is an example of
mechanisms to achieve the optimization.

4.2. Worst-Case Metrics

DetNet aims to enable real-time communications on top of a
heterogeneous multi-hop architecture. To make correct decisions, the
DetNet Controller Plane [RFC8655] needs timely information about
packet losses/delays for each flow and each hop of the paths. In
other words, just the average end-to-end statistics are not enough.
The collected information must be sufficient to allow a system to
predict the worst-case scenario.

5. Maintenance

Service protection (provided by the DetNet Service sub-layer) is
designed to mitigate simple network failures more rapidly than the
expected response time of the DetNet Controller Plane. In the face
of events that impact network operation (e.g., link up/down, device
crash/reboot, flows starting and ending), the DetNet Controller Plane
needs to perform repair and reoptimization actions in order to
permanently ensure SLOs of all active flows with minimal waste of
resources. The Controller Plane is expected to be able to
continuously retrieve the state of the network, to evaluate
conditions and trends about the relevance of a reconfiguration,
quantifying the following:

the cost of the suboptimality: resources may not be used optimally
(i.e., a better path exists).

the reconfiguration cost: the DetNet Controller Plane needs an
ability to trigger some reconfigurations. For this transient
period, resources may be twice reserved, and control packets have
to be transmitted.

Thus, reconfiguration may only be triggered if the gain is
significant.

5.1. Replication/Elimination

When multiple paths are reserved between two MEPs, packet replication
may be used to introduce redundancy and alleviate transmission errors
and collisions. For instance, in Figure 1, the source device S
transmits a packet to devices A and B to reach the destination node
R.

===> (A) => (C) => (E) ===
// \\// \\// \\
source (S) //\\ //\\ (R) (root)
\\ // \\ // \\ //
===> (B) => (D) => (F) ===

Figure 1: Packet Replication and Elimination Functions

5.2. Resource Reservation

Because the quality of service associated with a path may degrade,
the network has to provision additional resources along the path.

6. Requirements

According to [RFC8655], DetNet functionality is divided into
forwarding and service sub-layers. The DetNet forwarding sub-layer
includes DetNet transit nodes and may allocate resources for a DetNet
flow over paths provided by the underlay network. The DetNet service
sub-layer includes DetNet relay nodes and provides a DetNet service
(e.g., service protection). This section lists general requirements
for DetNet OAM as well as requirements in each of the DetNet sub-
layers of a DetNet domain.

1. It MUST be possible to initiate a DetNet OAM session from a MEP
located at a DetNet node towards a MEP or MEPs downstream from
that DetNet node within the given domain at a particular DetNet
sub-layer.

2. It MUST be possible to initiate a DetNet OAM session using any of
the DetNet Controller Plane solutions, e.g., a centralized
controller.

3. DetNet OAM MUST support proactive OAM monitoring and measurement
methods.

4. DetNet OAM MUST support on-demand OAM monitoring and measurement
methods.

5. DetNet OAM MUST support unidirectional OAM methods, continuity
checks, connectivity verification, and performance measurements.

6. DetNet OAM MUST support bidirectional DetNet flows, but it is not
required to support bidirectional OAM methods for bidirectional
DetNet flows. DetNet OAM test packets used for monitoring and
measurements of a bidirectional DetNet flow MUST be in band in
both directions.

7. DetNet OAM MUST support proactive monitoring of a DetNet device's
reachability for a given DetNet flow.

8. DetNet OAM MUST support hybrid performance measurement methods.

9. Calculated performance metrics MUST include, but are not limited
to, throughput, packet-loss, out-of-order, delay, and delay-
variation metrics. [RFC6374] provides detailed information on
performance measurement and performance metrics.

6.1. For the DetNet Forwarding Sub-layer

DetNet OAM MUST support:

1. PMTU discovery.

2. Remote Defect Indication (RDI) notification to the DetNet OAM
instance performing continuity checking.

3. the monitoring of levels of resources allocated for a particular
DetNet flow. Such resources include, but are not limited to,
buffer utilization and scheduler transmission calendar.

4. the monitoring of any subset of paths traversed through the
DetNet domain by a DetNet flow.

6.2. For the DetNet Service Sub-layer

The OAM functions for the DetNet service sub-layer allow, for
example, the recognizing/discovery of DetNet relay nodes, the
gathering of information about their configuration, and the checking
of their operation or status.

The requirements on OAM for a DetNet relay node are that DetNet OAM
MUST:

1. provide OAM functions for the DetNet service sub-layer.

2. support the discovery of DetNet relay nodes in a DetNet network.

3. support the discovery of PREOF locations in the domain.

4. support the collection of information specific to the DetNet
service sub-layer (configuration/operation/status) from DetNet
relay nodes.

5. support exercising functionality of PREOF in the domain.

6. work for DetNet data planes: MPLS and IP.

7. support a defect notification mechanism, like Alarm Indication
Signal. Any DetNet relay node providing service for a given
DetNet flow MAY originate a defect notification addressed to any
subset of DetNet relay nodes along that flow.

8. be able to measure metrics (e.g. delay) inside a collection of
OAM sessions, specially for complex DetNet flows, with PREOF
features.

7. IANA Considerations

This document has no IANA actions.

8. Security Considerations

This document lists the OAM requirements for a DetNet domain and does
not raise any security concerns or issues in addition to ones common
to networking and those specific to DetNet that are discussed in
Section 9 of [RFC9055]. Furthermore, the analysis of OAM security
concerns in Section 6 of [RFC7276] also applies to DetNet OAM,
including the use of OAM for network reconnaissance.

9. Privacy Considerations

Privacy considerations of DetNet discussed in Section 13 of [RFC9055]
are also applicable to DetNet OAM. If any privacy mechanism is used
for the monitored DetNet flow, then the same privacy method MUST be
applied to the active DetNet OAM used to monitor the flow.

10. References

10.1. 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/info/rfc2119>.

[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>.

[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.

10.2. Informative References

[HYBRID-TWO-STEP]
Mirsky, G., Lingqiang, W., Zhui, G., Song, H., and P.
Thubert, "Hybrid Two-Step Performance Measurement Method",
Work in Progress, Internet-Draft, draft-ietf-ippm-hybrid-
two-step-00, 4 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-ippm-
hybrid-two-step-00>.

[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544,
DOI 10.17487/RFC2544, March 1999,
<https://www.rfc-editor.org/info/rfc2544>.

[RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
D., and S. Mansfield, "Guidelines for the Use of the "OAM"
Acronym in the IETF", BCP 161, RFC 6291,
DOI 10.17487/RFC6291, June 2011,
<https://www.rfc-editor.org/info/rfc6291>.

[RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay
Measurement for MPLS Networks", RFC 6374,
DOI 10.17487/RFC6374, September 2011,
<https://www.rfc-editor.org/info/rfc6374>.

[RFC7276] Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
Weingarten, "An Overview of Operations, Administration,
and Maintenance (OAM) Tools", RFC 7276,
DOI 10.17487/RFC7276, June 2014,
<https://www.rfc-editor.org/info/rfc7276>.

[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.

[RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications
for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
September 2019, <https://www.rfc-editor.org/info/rfc8641>.

[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
<https://www.rfc-editor.org/info/rfc8939>.

[RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker,
"Deterministic Networking (DetNet) Security
Considerations", RFC 9055, DOI 10.17487/RFC9055, June
2021, <https://www.rfc-editor.org/info/rfc9055>.

[RFC9197] Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi,
Ed., "Data Fields for In Situ Operations, Administration,
and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
May 2022, <https://www.rfc-editor.org/info/rfc9197>.

[RFC9326] Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.
Mizrahi, "In Situ Operations, Administration, and
Maintenance (IOAM) Direct Exporting", RFC 9326,
DOI 10.17487/RFC9326, November 2022,
<https://www.rfc-editor.org/info/rfc9326>.

[RFC9341] Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T.,
and T. Zhou, "Alternate-Marking Method", RFC 9341,
DOI 10.17487/RFC9341, December 2022,
<https://www.rfc-editor.org/info/rfc9341>.

Acknowledgments

The authors express their appreciation and gratitude to Pascal
Thubert for the review, insightful questions, and helpful comments.

Authors' Addresses

Greg Mirsky
Ericsson
Email: [email protected]

Fabrice Theoleyre
CNRS
ICube Lab, Pole API
300 boulevard Sebastien Brant - CS 10413
67400 Illkirch - Strasbourg
France
Phone: +33 368 85 45 33
Email: [email protected]
URI: https://fabrice.theoleyre.cnrs.fr/

Georgios Papadopoulos
IMT Atlantique
Office B00 - 102A
2 Rue de la Châtaigneraie
35510 Cesson-Sévigné - Rennes
France
Phone: +33 299 12 70 04
Email: [email protected]

Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
28911 Leganes, Madrid
Spain
Phone: +34 91624 6236
Email: [email protected]
URI: http://www.it.uc3m.es/cjbc/

Balazs Varga
Ericsson
Budapest
Magyar Tudosok krt. 11.
1117
Hungary
Email: [email protected]

Janos Farkas
Ericsson
Budapest
Magyar Tudosok krt. 11.
1117
Hungary
Email: [email protected]