OPSAWG Y. Liu Internet-Draft China Mobile Intended status: Standards Track C. Lin Expires: 26 July 2026 New H3C Technologies 22 January 2026 Export of BIER Information in IP Flow Information Export (IPFIX) draft-ll-opsawg-ipfix-bier-00 Abstract This document introduces new IP Flow Information Export (IPFIX) Information Elements (IEs) to identify a set of information related to Bit Index Explicit Replication (BIER) such as data contained in BIER header that traffic is being forwarded with. 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/. 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Liu & Lin Expires 26 July 2026 [Page 1] Internet-Draft Export of BIER in IPFIX January 2026 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. New IPFIX BIER Information Elements . . . . . . . . . . . . . 3 4. Sample Use Cases . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 6.1. IPFIX Information Elements . . . . . . . . . . . . . . . 5 6.1.1. bierBIFTidSection . . . . . . . . . . . . . . . . . . 6 6.1.2. bierTTL . . . . . . . . . . . . . . . . . . . . . . . 7 6.1.3. bierFromMPLSNetwork . . . . . . . . . . . . . . . . . 7 6.1.4. bierVersion . . . . . . . . . . . . . . . . . . . . . 8 6.1.5. bierBSL . . . . . . . . . . . . . . . . . . . . . . . 8 6.1.6. bierEntropy . . . . . . . . . . . . . . . . . . . . . 9 6.1.7. bierOAMSection . . . . . . . . . . . . . . . . . . . 9 6.1.8. bierDSCP . . . . . . . . . . . . . . . . . . . . . . 10 6.1.9. bierNextProtocol . . . . . . . . . . . . . . . . . . 10 6.1.10. bierBFIRid . . . . . . . . . . . . . . . . . . . . . 11 6.1.11. bierBitString . . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1. Normative References . . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 1. Introduction [RFC8279] introduces a novel multicast data packet forwarding architecture known as "Bit Index Explicit Replication" (BIER). This architecture achieves optimal forwarding within a "multicast domain" without relying on explicit tree-building protocols or requiring intermediate nodes to maintain per-flow state. Currently, BIER technology has been widely adopted in modern data centers and large- scale networks, significantly enhancing the efficiency and scalability of multicast transmission. [RFC8296] defines the encapsulation of BIER header that provides the information needed to support the BIER forwarding procedures. This document specifies new IPFIX Information Elements (IEs) within the "IPFIX Information Elements" registry [RFC7012], for BIER purposes. These IEs are used to export the main parameters of BIER flow. Liu & Lin Expires 26 July 2026 [Page 2] Internet-Draft Export of BIER in IPFIX January 2026 2. Terminology 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. This document makes use of the terms defined in [RFC7011]. The following terms are used as defined in [RFC7011]: * IPFIX * IPFIX Information Elements The following terms are used as defined in [RFC8296]: * TC * TTL * BFR * BIFT * BFIR * BFER * BSL * SD * SI 3. New IPFIX BIER Information Elements This section specifies the new IPFIX BIER IEs. bierBIFTidSection The BIFT-id, TC, and S fields defined in the initial three octets of the BIER header (Section 2 of [RFC8296]). bierTTL The value of the TTL field in the BIER header (Section 2 of [RFC8296]). This IE indicates the incoming Time to Live (TTL) when a BIER packet is received. Liu & Lin Expires 26 July 2026 [Page 3] Internet-Draft Export of BIER in IPFIX January 2026 bierFromMPLSNetwork This IE indicates whether the BIER packet is from an MPLS network. bierVersion The version of the BIER header (Section 2 of [RFC8296]). bierBSL The value of the BSL field in the BIER header (Section 2 of [RFC8296]). This IE indicates the length in bits of the BitString defined in the BIER header (Section 2 of [RFC8296]). bierEntropy The value of the Entropy field in the BIER header (Section 2 of [RFC8296]). It is can be used for load-balancing purposes. bierOAMSection The OAM and Rsv field from the BIER header (Section 2 of [RFC8296]). bierDSCP The value of the DSCP field in the BIER header (Section 2 of [RFC8296]). In Non-MPLS networks, it is used to hold a Differentiated Services Codepoint [RFC2474]. bierNextProtocol The next protocol defined in the Proto field of the BIER header (Section 2 of [RFC8296]). It identifies the type of the payload following the BIER header. bierBFIRid The value of the BFIR-id field in the BIER header (Section 2 of [RFC8296]). It indicates the BFR-id of the BFIR in the SD to which the packet has been assigned. bierBitString The BitString field defined in the BIER header (Section 2 of [RFC8296]). Together with the packet's SI and SD, it identifies the destination BFERs for this packet. 4. Sample Use Cases The IPFIX IEs defined in the Section 3, and some existing IP packet header information [IANA-IPFIX] provide answers to the following questions (amongst others). * Whether the IP packet is a BIER packet? * Whether the BIER packet is from an MPLS network? Liu & Lin Expires 26 July 2026 [Page 4] Internet-Draft Export of BIER in IPFIX January 2026 * What is the incoming TTL of the BIER packet? * What is BIER version used by the BIER packet? * What is the type of the payload following the BIER header in the BIER packet? * What is the destination BFERs for the BIER packet? 5. Security Considerations There exists no extra security considerations other than those already discussed in Section 11 of [RFC7011] and Section 8 of [RFC7012]. 6. IANA Considerations 6.1. IPFIX Information Elements This document requests IANA to add new IPFIX BIER IEs to the "IPFIX Information Elements" registry [RFC7012] available at [IANA-IPFIX]. Table 1 lists the new IPFIX BIER IEs: Liu & Lin Expires 26 July 2026 [Page 5] Internet-Draft Export of BIER in IPFIX January 2026 +============+=============================+===============+ | Element ID | Name | Reference | +============+=============================+===============+ | TBD1 | bierBIFTidSection | This document | +------------+-----------------------------+---------------+ | TBD2 | bierTTL | This document | +------------+-----------------------------+---------------+ | TBD3 | bierFromMPLSNetwork | This document | +------------+-----------------------------+---------------+ | TBD4 | bierVersion | This document | +------------+-----------------------------+---------------+ | TBD5 | bierBSL | This document | +------------+-----------------------------+---------------+ | TBD6 | bierEntropy | This document | +------------+-----------------------------+---------------+ | TBD7 | bierOAMSection | This document | +------------+-----------------------------+---------------+ | TBD8 | bierDSCP | This document | +------------+-----------------------------+---------------+ | TBD9 | bierNextProtocol | This document | +------------+-----------------------------+---------------+ | TBD10 | bierBFIRid | This document | +------------+-----------------------------+---------------+ | TBD11 | bierBitString | This document | +------------+-----------------------------+---------------+ Table 1: New BIER IEs in the "IPFIX Information Elements" Registry 6.1.1. bierBIFTidSection ElementID: TBD1 Name: bierBIFTidSection Abstract Data Type: octetArray Data Type Semantics: identifier Status: current Description: The BIFT-id, TC, and S fields defined in the initial three octets of the BIER header. The size of this information Element is 3 octets. Liu & Lin Expires 26 July 2026 [Page 6] Internet-Draft Export of BIER in IPFIX January 2026 0 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BIFT-id | TC |S| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ BIFT-id: BIFT id, 20 bits TC: Traffic Class, 3 bits S: Set to 1, 1 bit Additional Information: See Section 2 of [RFC8296] for more details about the BIFT-id, TC, and S fields. Reference: [this document] 6.1.2. bierTTL ElementID: TBD2 Name: bierTTL Abstract Data Type: unsigned8 Data Type Semantics: default Status: current Description: The value of the TTL field in the BIER header. This Information Element indicates the incoming TTL when a BIER packet is received. Units: hops Additional Information: See Section 2 of [RFC8296] for more details about the TTL fields. Reference: [this document] 6.1.3. bierFromMPLSNetwork ElementID: TBD3 Name: bierFromMPLSNetwork Abstract Data Type: boolean Data Type Semantics: default Liu & Lin Expires 26 July 2026 [Page 7] Internet-Draft Export of BIER in IPFIX January 2026 Status: current Description: This IE indicates whether the BIER packet is from an MPLS network. Additional Information: In MPLS networks, the Nibble field of the BIER header MUST be set to the binary value 0101. In Non-MPLS networks, the Nibble field is set to the binary value 0000. Therefore, the Nibble field can be used to identify whether a BIER packet is from an MPLS network. See Section 2 of [RFC8296] for more details. Reference: [this document] 6.1.4. bierVersion ElementID: TBD4 Name: bierVersion Abstract Data Type: unsigned8 Data Type Semantics: identifier Status: current Description: The version value of the Ver field in the BIER header. This Information Element encodes only the 4 bits of the Ver field. Therefore, its value may range from 0 to 0xF. Additional Information: See Section 2 of [RFC8296] for more details about the Ver field of the BIER header. Reference: [this document] 6.1.5. bierBSL ElementID: TBD5 Name: bierBSL Abstract Data Type: unsigned8 Data Type Semantics: default Status: current Liu & Lin Expires 26 July 2026 [Page 8] Internet-Draft Export of BIER in IPFIX January 2026 Description: The value of the BSL field in the BIER header. This Information Element indicates the length in bits of the BitString defined in the BIER header. This Information Element encodes only the 4 bits of the BSL field. Therefore, its value may range from 0 to 15. Additional Information: See Section 2 of [RFC8296] for more details about the BSL field of the BIER header. Reference: [this document] 6.1.6. bierEntropy ElementID: TBD6 Name: bierEntropy Abstract Data Type: unsigned32 Data Type Semantics: default Status: current Description: The value of the Entropy field in the BIER header. This Information Element indicates the function of load-balancing. This Information Element encodes only the 20 bits of the Entropy field. Therefore, its value may range from 0 to 0xFFFFF. Additional Information: See Section 2 of [RFC8296] for more details about the Entropy field of the BIER header. Reference: [this document] 6.1.7. bierOAMSection ElementID: TBD7 Name: bierOAMSection Abstract Data Type: unsigned8 Data Type Semantics: flags Status: current Description: The OAM and Rsv field from the BIER header. Liu & Lin Expires 26 July 2026 [Page 9] Internet-Draft Export of BIER in IPFIX January 2026 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |OAM|Rsv|no care| +-+-+-+-+-+-+-+-+ Bits 0-1: OAM field. Bits 2-3: Rsv field, unused. Bits 4-7: No care, value is irrelevent. Additional Information: See Section 2 of [RFC8296] for more details about the OAM and Rsv field of the BIER header. Reference: [this document] 6.1.8. bierDSCP ElementID: TBD8 Name: bierDSCP Abstract Data Type: unsigned8 Data Type Semantics: identifier Status: current Description: The value of the DSCP field in the BIER header. In Non-MPLS networks, it is used to hold a Differentiated Services Codepoint. This Information Element encodes only the 6 bits of the DSCP field. Therefore, its value may range from 0 to 63. Additional Information: See Section 2 of [RFC8296] for more details about the DSCP field of the BIER header. Reference: [this document] 6.1.9. bierNextProtocol ElementID: TBD9 Name: bierNextProtocol Abstract Data Type: unsigned8 Data Type Semantics: identifier Liu & Lin Expires 26 July 2026 [Page 10] Internet-Draft Export of BIER in IPFIX January 2026 Status: current Description: The next protocol defined in the Proto field of the BIER header. This Information Element identifies the type of the payload following the BIER header. This Information Element encodes only the 6 bits of the Proto field. Therefore, its value may range from 0 to 63. Additional Information: See Section 2 of [RFC8296] for more details about the Proto field of the BIER header. Reference: [this document] 6.1.10. bierBFIRid ElementID: TBD10 Name: bierBFIRid Abstract Data Type: unsigned16 Data Type Semantics: identifier Status: current Description: The value of the BFIR-id field in the BIER header. This Information Element identifies the BFR-id of the BFIR in the SD to which the packet has been assigned. Additional Information: See Section 2 of [RFC8296] for more details about the BFIR-id field of the BIER header. Reference: [this document] 6.1.11. bierBitString ElementID: TBD11 Name: bierBitString Abstract Data Type: octetArray Data Type Semantics: identifier Status: current Description: The BitString field defined in the BIER header. Liu & Lin Expires 26 July 2026 [Page 11] Internet-Draft Export of BIER in IPFIX January 2026 Together with the packet's SI and SD, this information Element identifies the destination BFERs for this packet. Additional Information: See Section 2 of [RFC8296] for more details about the BitString field of the BIER header. Reference: [this document] 7. References 7.1. 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, . [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, DOI 10.17487/RFC2474, December 1998, . [RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken, "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information", STD 77, RFC 7011, DOI 10.17487/RFC7011, September 2013, . [RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model for IP Flow Information Export (IPFIX)", RFC 7012, DOI 10.17487/RFC7012, September 2013, . [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, . Liu & Lin Expires 26 July 2026 [Page 12] Internet-Draft Export of BIER in IPFIX January 2026 [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, . 7.2. Informative References [IANA-IPFIX] "IP Flow Information Export (IPFIX) Entities", n.d., . Authors' Addresses Yisong Liu China Mobile 32 Xuanwumen West Street Beijing Xicheng District, 100053 China Email: liuyisong@chinamobile.com Changwang Lin New H3C Technologies 8 Yongjia North Road Beijing Haidian District, 100094 China Email: linchangwang.04414@h3c.com Liu & Lin Expires 26 July 2026 [Page 13]