BIER Working Group
Internet Engineering Task Force (IETF) G. Mirsky, Ed.
Internet-Draft
Request for Comments: 9974 Ericsson
Intended status:
Category: Informational N. Kumar
Expires: 27 May 2026
ISSN: 2070-1721 Oracle
M. Chen
Huawei Technologies
S. Pallagatti, Ed.
VMware
23 November 2025
May 2026
Operations, Administration Administration, and Maintenance (OAM) Requirements for the
Bit Index Explicit Replication (BIER) Layer
draft-ietf-bier-oam-requirements-21
Abstract
This document specifies a list of functional requirements for
Operations, Administration, and Maintenance mechanisms, protocols,
and tools that support operations in the Bit Index Explicit
Replication layer of a network.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 27 May 2026.
https://www.rfc-editor.org/info/rfc9974.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used Used in this document . . . . . . . . . . . . 2 This Document
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 2
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
1.1.3. Acronyms . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
6. References
5.1. Normative References . . . . . . . . . . . . . . . . . . . . 7
7.
5.2. Informative References . . . . . . . . . . . . . . . . . . . 7
Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 9
Acknowledgements
Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
[RFC8279] specifies a Bit Index Explicit Replication (BIER)
architecture and how it supports forwarding of multicast data
packets.
This document lists the Operations, Administration, and Maintenance
(OAM) requirements for the BIER layer (Section (see Section 4.2 of [RFC8279])
of the multicast domain. The list can further be used for gap
analysis of available OAM tools to identify whether possible
enhancements of existing or whether new OAM tools are required to support
proactive and on-
demand on-demand path monitoring and service validation.
1.1. Conventions used Used in this document This Document
1.1.1. Terminology
The reader is expected to be familiar with:
* [RFC7799], particularly definitions of Active, Passive, and Hybrid
measurement methods and metrics.
* The definitions and calculation of performance metrics, e.g.,
throughput, loss, delay, and delay variation metrics, are defined
in [RFC6374].
* The definitions, applicability, and examples of the Continuity
Check and Connectivity Verification mechanisms, components of the
Fault Management OAM, can be found in [RFC5860],[RFC6371], [RFC5860], [RFC6371], and
[RFC7276].
* A multicast domain is a network segment that defines the scope for
the
multicast traffic, allowing it to be exchanged only among systems
within the domain [RFC8279].
* The term "BIER OAM" is used in this document interchangeably with
"a set of OAM protocols, methods, and tools for the BIER layer".
* Downstream - is the direction from the ingress toward the egress
endpoints of a multicast distribution tree.
* Egress endpoint is a router to which the packet needs to be sent
[RFC8279].
* Ingress endpoint is a router that encapsulates a packet in a BIER
header [RFC8279].
* A BIER OAM session is a communication established between Bit-
Forwarding Routers (BFR) to perform OAM functions like fault
detection, performance monitoring, and localization [RFC7276].
These sessions can be proactive (continuous, persistent
configuration) or on-demand (manual, temporary diagnostics).
1.1.2. 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 Section 2 and applies to
implementations of BIER OAM conformant to the listed requirements.
1.1.3. Acronyms
BFD: Bidirectional Forwarding Detection [RFC8562]
BFR: Bit-Forwarding Router [RFC8279]
BFER: Bit-Forwarding Egress Router [RFC8279]
BIER: Bit Index Explicit Replication [RFC8279]
OAM: Operations, Administration, and Maintenance [RFC6291]
PMTUD: Path Maximum Transmission Unit Discovery [RFC1191]
p2mp:
P2MP: Point-to-Multipoint [RFC8562]
RDI: Remote Defect Indication [RFC6428]
STAMP: Simple Two-way Active Measurement Protocol [RFC8762]
2. Requirements
This section lists the requirements for OAM of the BIER layer:
1. The listed requirements MUST be supported with any routing
underlay [RFC8279] over which the BIER layer can be realized.
2. It MUST be possible to initialize a BIER OAM session from any
BFR of the given BIER domain.
3. It MUST be possible to initialize a BIER OAM session from a
controller.
4. BIER OAM MUST support proactive OAM monitoring and measurement
methods.
5. BIER OAM MUST support on-demand OAM monitoring and measurement
methods.
6. BIER OAM MUST support active performance measurement methods
[RFC7799].
7. BIER OAM MUST support passive performance measurement methods
[RFC7799].
8. BIER OAM MUST support the ability of any BFR in the given BIER
domain to proactively monitor Bit-Forwarding Egress Router
(BFER)
availability proactively. availability.
This requirement provides helpful clarification to the
combination of Requirements 2 and 4. The p2mp P2MP BFD with active
tail support [RFC9780] is an example of a protocol that provides
notifications about the loss of connectivity in a multicast
distribution tree.
9. BIER OAM MUST support downstream path continuity check. checking.
Bidirectional Forwarding Detection (BFD) [RFC8562] is an example
of a protocol that monitors the continuity of a multicast
distribution tree.
10. BIER OAM MUST support downstream performance measurement.
Simple Two-way Active Measurement Protocol (STAMP) [RFC8762] is
an example of a protocol that supports measurement of
performance metrics, e.g., packet loss ratio, delay, and delay
variation.
11. In the downstream direction, a BIER OAM solution MUST support
transmission of OAM packets to traverse the same set of nodes
and links and receive the same forwarding treatment (including
QoS) as the monitored BIER flow.
In some cases, e.g., when monitoring a composite data flow that
includes several sub-flows characterized by different CoS Class-of-
Service (CoS) marking, an operator may choose to monitor the
continuity of the path at the highest CoS, not at every CoS
value in the data flow. In that case, BIER OAM packets traverse
the same set of nodes and links as the composite data flow while
receiving the same forwarding treatment as the highest CoS sub-flow. sub-
flow. In this scenario, the state of path continuity for lower
CoS sub-flows can be derived from the state of the highest CoS,
as determined by the BIER OAM protocol performing continuity
verification (e.g., BFD).
12. BIER OAM MUST support bidirectional OAM methods. In the
downstream direction, these methods of monitoring or measurement
MUST conform to Requirement 11. In the reverse direction (i.e.,
from the egress toward the ingress endpoint of the BIER OAM test
session), BIER OAM packets MAY deviate from traversing the same
set of nodes and links, or receive a different forwarding
treatment (including QoS) as the monitored BIER flow.
Point-to-Multipoint (p2mp) (P2MP) BFD with active tail [RFC9780]) [RFC9780] is an
example of the bidirectional mechanism of continuity checking.
13. BIER OAM MUST support Path Maximum Transmission Unit discovery Discovery
(PMTUD).
The PMTUD using ICMP [RFC1191] is an example of the mechanism.
14. BIER OAM MUST support an RDI mechanism to notify the BFR, the
source of the continuity checking by BFERs.
The Diagnostic field in p2mp P2MP BFD with active tail support, as
described in Section 5 of [RFC9780], is an example of the RDI
mechanism.
15. BIER OAM MUST support downstream performance measurement
method(s) that (together) calculate performance metrics, e.g.,
throughput, loss, delay, and delay variation metrics [RFC6374].
STAMP ([RFC8762] and [RFC8972]) is an example of an active
performance measurement method of performance metrics that may
be applied in a BIER domain. The Alternate Marking Alternate-Marking Method,
described in [RFC9341] and [RFC9342], is an example of a hybrid
measurement method
([RFC7799]) [RFC7799] that may be applied in a BIER
domain.
16. BIER OAM MUST support defect notification mechanism(s).
Alarm Indication Signal [RFC6427] is an example of the defect
notification mechanism.
17. BIER OAM MUST support a way for any BFR in the given BIER domain
to originate a fault management message addressed to any subset
of BFRs within the domain.
[RFC6427] provides an example of a Fault Management messaging
mechanism.
18. BIER OAM MUST support methods to enable the survivability of a
BIER layer.
Protection switching and restoration are examples of
survivability methods.
3. IANA Considerations
This document does not propose any has no IANA consideration. This section
may be removed. actions.
4. Security Considerations
This document lists the OAM requirements for a BIER-enabled domain
and it thus inherits the security considerations discussed in
[RFC8279] and [RFC8296]. Another general security aspect results
from using active OAM protocols ([RFC7799]) [RFC7799] in a multicast network.
Active OAM protocols inject specially constructed test packets. Some
active OAM protocols are based on the echo request/reply principle of
using those test packets. In the multicast network, test packets are
replicated as data packets, thus creating a possible amplification
effect of multiple echo replies being transmitted to the sender of
the echo request. Thus, Therefore, the following security-related
requirements are defined for BIER OAM:
* A BIER OAM solution MUST protect the control plane by controlling
the rate of echo request transmission.
* A BIER OAM solution MUST provide control of the number of BIER OAM
messages sent to the control plane.
5. Acknowledgements
The authors would like to thank the comments and suggestions from
Gunter van de Velde that helped improve this document.
6. References
5.1. 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>.
[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>.
[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>.
[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>.
[RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
Explicit Replication (BIER)", RFC 8279,
DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>.
7.
5.2. Informative References
[RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
DOI 10.17487/RFC1191, November 1990,
<https://www.rfc-editor.org/info/rfc1191>.
[RFC5860] Vigoureux, M., Ed., Ward, D., Ed., and M. Betts, Ed.,
"Requirements for Operations, Administration, and
Maintenance (OAM) in MPLS Transport Networks", RFC 5860,
DOI 10.17487/RFC5860, May 2010,
<https://www.rfc-editor.org/info/rfc5860>.
[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>.
[RFC6371] Busi, I., Ed. and D. Allan, Ed., "Operations,
Administration, and Maintenance Framework for MPLS-Based
Transport Networks", RFC 6371, DOI 10.17487/RFC6371,
September 2011, <https://www.rfc-editor.org/info/rfc6371>.
[RFC6427] Swallow, G., Ed., Fulignoli, A., Ed., Vigoureux, M., Ed.,
Boutros, S., and D. Ward, "MPLS Fault Management
Operations, Administration, and Maintenance (OAM)",
RFC 6427, DOI 10.17487/RFC6427, November 2011,
<https://www.rfc-editor.org/info/rfc6427>.
[RFC6428] Allan, D., Ed., Swallow, G., Ed., and J. Drake, Ed.,
"Proactive Connectivity Verification, Continuity Check,
and Remote Defect Indication for the MPLS Transport
Profile", RFC 6428, DOI 10.17487/RFC6428, November 2011,
<https://www.rfc-editor.org/info/rfc6428>.
[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>.
[RFC8562] Katz, D., Ward, D., Pallagatti, S., Ed., and G. Mirsky,
Ed., "Bidirectional Forwarding Detection (BFD) for
Multipoint Networks", RFC 8562, DOI 10.17487/RFC8562,
April 2019, <https://www.rfc-editor.org/info/rfc8562>.
[RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
Two-Way Active Measurement Protocol", RFC 8762,
DOI 10.17487/RFC8762, March 2020,
<https://www.rfc-editor.org/info/rfc8762>.
[RFC8972] Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A.,
and E. Ruffini, "Simple Two-Way Active Measurement
Protocol Optional Extensions", RFC 8972,
DOI 10.17487/RFC8972, January 2021,
<https://www.rfc-editor.org/info/rfc8972>.
[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>.
[RFC9342] Fioccola, G., Ed., Cociglio, M., Sapio, A., Sisto, R., and
T. Zhou, "Clustered Alternate-Marking Method", RFC 9342,
DOI 10.17487/RFC9342, December 2022,
<https://www.rfc-editor.org/info/rfc9342>.
[RFC9780] Mirsky, G., Mishra, G., and D. Eastlake 3rd,
"Bidirectional Forwarding Detection (BFD) for Multipoint
Networks over Point-to-Multipoint MPLS Label Switched
Paths (LSPs)", RFC 9780, DOI 10.17487/RFC9780, May 2025,
<https://www.rfc-editor.org/info/rfc9780>.
Contributors' Addresses
Acknowledgements
The authors would like to thank Gunter van de Velde for the comments
and suggestions that helped improve this document.
Contributors
Erik Nordmark
Email: nordmark@acm.org
Sam Aldrin
Google
Email: aldrin.ietf@gmail.com
Lianshu Zheng
Email: veronique_cheng@hotmail.com
Nobo Akiya
Email: nobo.akiya.dev@gmail.com
Authors' Addresses
Greg Mirsky (editor)
Ericsson
Email: gregimirsky@gmail.com
Nagendra Kumar
Oracle
Email: nagendrakumar.nainar@gmail.com
Mach Chen
Huawei Technologies
Email: mach.chen@huawei.com
Santosh Pallagatti (editor)
VMware
Email: santosh.pallagatti@gmail.com