BIER Working Group G. Mirsky, Ed. Internet-Draft Ericsson Intended status: Informational N. Kumar Expires: 27 May 2026 Oracle M. Chen Huawei Technologies S. Pallagatti, Ed. VMware 23 November 2025 Operations, Administration and Maintenance (OAM) Requirements for 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 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 27 May 2026. Copyright Notice Copyright (c) 2025 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 Mirsky, et al. Expires 27 May 2026 [Page 1] Internet-Draft OAM Requirements for BIER November 2025 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 1.1. Conventions used in this document . . . . . . . . . . . . 2 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. Normative References . . . . . . . . . . . . . . . . . . . . 7 7. Informative References . . . . . . . . . . . . . . . . . . . 7 Contributors' Addresses . . . . . . . . . . . . . . . . . . . . . 9 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 4.2 of [RFC8279]) of the multicast domain. The list can further be used for gap analysis of available OAM tools to identify possible enhancements of existing or whether new OAM tools are required to support proactive and on- demand path monitoring and service validation. 1.1. Conventions used in 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]. Mirsky, et al. Expires 27 May 2026 [Page 2] Internet-Draft OAM Requirements for BIER November 2025 * 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], 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] Mirsky, et al. Expires 27 May 2026 [Page 3] Internet-Draft OAM Requirements for BIER November 2025 OAM: Operations, Administration, and Maintenance [RFC6291] PMTUD: Path Maximum Transmission Unit Discovery [RFC1191] 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 monitor Bit-Forwarding Egress Router (BFER) availability proactively. This requirement provides helpful clarification to the combination of Requirements 2 and 4. The 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. Mirsky, et al. Expires 27 May 2026 [Page 4] Internet-Draft OAM Requirements for BIER November 2025 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 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. 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) BFD with active tail [RFC9780]) is an example of the bidirectional mechanism of continuity checking. 13. BIER OAM MUST support Path Maximum Transmission Unit 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 BFD with active tail support, as described in Section 5 of [RFC9780], is an example of the RDI mechanism. Mirsky, et al. Expires 27 May 2026 [Page 5] Internet-Draft OAM Requirements for BIER November 2025 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 Method, described in [RFC9341] and [RFC9342], is an example of a hybrid measurement method ([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 IANA consideration. This section may be removed. 4. Security Considerations This document lists the OAM requirements for a BIER-enabled domain and thus inherits the security considerations discussed in [RFC8279] and [RFC8296]. Another general security aspect results from using active OAM protocols ([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, following security-related requirements for BIER OAM: Mirsky, et al. Expires 27 May 2026 [Page 6] Internet-Draft OAM Requirements for BIER November 2025 * 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. 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, . [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay Measurement for MPLS Networks", RFC 6374, DOI 10.17487/RFC6374, September 2011, . [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, May 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [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, . 7. Informative References [RFC1191] Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191, DOI 10.17487/RFC1191, November 1990, . Mirsky, et al. Expires 27 May 2026 [Page 7] Internet-Draft OAM Requirements for BIER November 2025 [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, . [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, . [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, . [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, . [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, . [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, . [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, . [RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple Two-Way Active Measurement Protocol", RFC 8762, DOI 10.17487/RFC8762, March 2020, . Mirsky, et al. Expires 27 May 2026 [Page 8] Internet-Draft OAM Requirements for BIER November 2025 [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, . [RFC9341] Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T., and T. Zhou, "Alternate-Marking Method", RFC 9341, DOI 10.17487/RFC9341, December 2022, . [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, . [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, . Contributors' Addresses 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 Mirsky, et al. Expires 27 May 2026 [Page 9] Internet-Draft OAM Requirements for BIER November 2025 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 Mirsky, et al. Expires 27 May 2026 [Page 10]