Network Working Group T. Graf Internet-Draft Swisscom Intended status: Standards Track B. Claise Expires: 26 November 2023 Huawei P. Francois INSA-Lyon 25 May 2023 Export of Segment Routing over IPv6 Information in IP Flow Information Export (IPFIX) draft-ietf-opsawg-ipfix-srv6-srh-14 Abstract This document introduces new IP Flow Information Export (IPFIX) Information Elements to identify a set of Segment Routing over IPv6 (SRv6) related information such as data contained in a Segment Routing Header (SRH), the SRv6 control plane, and the SRv6 endpoint behavior 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/. 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 26 November 2023. Copyright Notice Copyright (c) 2023 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 Graf, et al. Expires 26 November 2023 [Page 1] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 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 . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. New IPFIX IPv6 SRH Information Elements . . . . . . . . . . . 4 4. Sample Use Cases . . . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5.1. New IPFIX IPv6 SRH Information Elements . . . . . . . . . 6 5.1.1. srhFlagsIPv6 . . . . . . . . . . . . . . . . . . . . 7 5.1.2. srhTagIPv6 . . . . . . . . . . . . . . . . . . . . . 8 5.1.3. srhSegmentIPv6 . . . . . . . . . . . . . . . . . . . 8 5.1.4. srhActiveSegmentIPv6 . . . . . . . . . . . . . . . . 9 5.1.5. srhSegmentIPv6BasicList . . . . . . . . . . . . . . . 9 5.1.6. srhSegmentIPv6ListSection . . . . . . . . . . . . . . 9 5.1.7. srhSegmentsIPv6Left . . . . . . . . . . . . . . . . . 10 5.1.8. srhIPv6Section . . . . . . . . . . . . . . . . . . . 10 5.1.9. srhIPv6ActiveSegmentType . . . . . . . . . . . . . . 11 5.1.10. srhSegmentIPv6LocatorLength . . . . . . . . . . . . . 11 5.1.11. srhSegmentIPv6EndpointBehavior . . . . . . . . . . . 11 5.2. New IPFIX IPv6 SRH Segment Type Subregistry . . . . . . . 12 6. Operational Considerations . . . . . . . . . . . . . . . . . 13 6.1. SRv6 Segment List . . . . . . . . . . . . . . . . . . . . 13 6.2. Compressed SRv6 Segment List Decomposition . . . . . . . 14 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 8. Implementation Status . . . . . . . . . . . . . . . . . . . . 14 8.1. FD.io VPP . . . . . . . . . . . . . . . . . . . . . . . . 14 8.2. Huawei VRP . . . . . . . . . . . . . . . . . . . . . . . 15 8.3. Pmacct Data Collection . . . . . . . . . . . . . . . . . 15 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 10.1. Normative References . . . . . . . . . . . . . . . . . . 16 10.2. Informative References . . . . . . . . . . . . . . . . . 16 Appendix A. IPFIX Encoding Examples . . . . . . . . . . . . . . 18 A.1. Three Observed SRH Headers and their Routing Protocol . . 18 A.1.1. Template Record and Data Set with Segment Basic List . . . . . . . . . . . . . . . . . . . . . . . . 19 A.1.2. Template Record and Data Set with Segment List Section . . . . . . . . . . . . . . . . . . . . . . . 21 A.1.3. Template Record and Data Set with SRH Section . . . . 24 A.2. Options Template Record and Data Set for SRv6 Segment End Point behavior and Locator Length . . . . . . . . . . . . 26 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 Graf, et al. Expires 26 November 2023 [Page 2] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 1. Introduction A dedicated Routing Extension Header, called Segment Routing Header (SRH), is defined in [RFC8754] for use of Segment Routing (SR) over IPv6 data plane. Also, three routing protocol extensions, OSPFv3 [I-D.ietf-lsr-ospfv3-srv6-extensions], IS-IS [RFC9352] and BGP Prefix Segment Identifiers(Prefix-SIDs) [RFC8669] and Path Computation Element Communication Protocol (PCEP) Extension [I-D.ietf-pce-segment-routing-ipv6] and Segment Routing Policy [RFC9256] are defined to propagate Segment Identifiers (SIDs). SRv6 segment endpoint behaviors describe how packets should be processed by SRv6 Segment Endpoint Nodes. Such behaviors are defined in [RFC8986]. This document specifies eleven new IPFIX Information Elements (IEs) and one new subregistry within the "IPFIX Information Elements" registry [RFC7012], for SRv6 purposes. These IEs are used to export the SRv6 active segment and its control plane protocol, the SRv6 Segment List, the next SRv6 node and its type, and the numbers of SRv6 segments left. Some examples are provided in Appendix A. 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], [RFC8402] and [RFC8754]. The following terms are used as defined in [RFC7011]: * IPFIX * IPFIX Information Elements * Template * Template Record Graf, et al. Expires 26 November 2023 [Page 3] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 * Options Template * Options Template Record * Data Record * Data Set The following terms are used as defined in [RFC8402]: * Segment Routing (SR) * Segment * Segment List * Active Segment * Segment Identifier (SID) * SRv6 * SRv6 SID The following terms are used as defined in [RFC8754]: * Segment Routing Header (SRH) * SR Source Node * Transit Node * SR Segment Endpoint Node * Reduced SRH * Segments Left * Last Entry 3. New IPFIX IPv6 SRH Information Elements This section specifies the new IPFIX IPv6 SRH IEs. srhFlagsIPv6 8-bit flags defined in the SRH (Section 2 of [RFC8754]). Graf, et al. Expires 26 November 2023 [Page 4] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 srhTagIPv6 16-bit tag field defined in the SRH (Section 2 of [RFC8754]). A tag is used to mark a packet as part of a class or group of packets sharing the same set of properties. srhSegmentIPv6 128-bit IPv6 address that represents a SRv6 segment. srhActiveSegmentIPv6 128-bit IPv6 address that represents the active SRv6 segment. srhSegmentIPv6BasicList Ordered basicList [RFC6313] of zero or more 128-bit IPv6 addresses in the SRH that represents the SRv6 Segment List. As specified in Section 2 of [RFC8754], the Segment List is encoded starting from the last segment of the SR Policy. That is, the first element of the Segment List (Segment List[0]) contains the last segment of the SR Policy, the second element contains the penultimate segment of the SR Policy, and so on. srhSegmentIPv6ListSection The SRH Segment List as defined in Section 2 of [RFC8754] as a series of octets in IPFIX. srhSegmentsIPv6Left 8-bit unsigned integer defining the number of segments remaining to reach the end of the Segment List from the SRH, as specified by the "Segments Left" field in Section 4.4 of [RFC8200] and mentioned part of the SRH in Section 2 of [RFC8754]). srhIPv6Section Exposes the SRH and its TLVs as specified in Section 2 of [RFC8754] as a series of octets in IPFIX. srhIPv6ActiveSegmentType Designator of the routing protocol or PCEP extension where the active SRv6 segment has been learned from. srhSegmentIPv6LocatorLength The SRH segment IPv6 locator length specified as the number of significant bits. Together with srhSegmentIPv6 it enables the calculation of the SRv6 Locator. srhSegmentIPv6EndpointBehavior 16-bit unsigned integer that represents a SRv6 Endpoint behavior as per Section 4 of [RFC8986]. Graf, et al. Expires 26 November 2023 [Page 5] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 Note that the srhSegmentIPv6, srhSegmentIPv6LocatorLength, and srhSegmentIPv6EndpointBehavior IPFIX IEs are generic fields, to be used in the context of IPFIX Options Templates or IPFIX Structured Data [RFC6313]. 4. Sample Use Cases The IPFIX IEs srhSegmentIPv6BasicList (TBD5) or srhSegmentIPv6ListSection (TBD6), srhActiveSegmentIPv6 (TBD4), srhSegmentsIPv6Left (TBD7), srhIPv6ActiveSegmentType(TBD9), forwardingStatus (89) [RFC7270] [IANA-IPFIX], and some existing counter informations [IANA-IPFIX] providing answers to the following questions (amongst others): * How many packets steered with a SR policy are forwarded or dropped using SRv6 in a network? * If dropped, for which reasons? * What is the current active segment and its associated control plane protocol? * What is the SRv6 Segment List? * What is the next SRv6 node and its type? * How many SRv6 segments are left? 5. IANA Considerations Note to the RFC-Editor: * Please replace TBD1 - TBD17 with the values allocated by IANA * Please replace the [RFC-to-be] with the RFC number assigned to this document 5.1. New IPFIX IPv6 SRH Information Elements This document requests IANA to add new IEs (Section 5.1) to the "IPFIX Information Elements" registry [RFC7012] available at [IANA-IPFIX]. Table 1 lists the new IPv6 SRH IEs: Graf, et al. Expires 26 November 2023 [Page 6] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 +-------+--------------------------------+ |Element| Name | | ID | | +-------+--------------------------------+ | TBD1 | srhFlagsIPv6 | | | | +-------+--------------------------------+ | TBD2 | srhTagIPv6 | | | | +-------+--------------------------------+ | TBD3 | srhSegmentIPv6 | | | | +-------+--------------------------------+ | TBD4 | srhActiveSegmentIPv6 | | | | +-------+--------------------------------+ | TBD5 | srhSegmentIPv6BasicList | | | | +-------+--------------------------------+ | TBD6 | srhSegmentIPv6ListSection | | | | +-------+--------------------------------+ | TBD7 | srhSegmentsIPv6Left | | | | +-------+--------------------------------+ | TBD8 | srhIPv6Section | | | | +-------+--------------------------------+ | TBD9 | srhIPv6ActiveSegmentType | | | | +-------+--------------------------------+ | TBD10 | srhSegmentIPv6LocatorLength | | | | +-------+--------------------------------+ | TBD11 | srhSegmentIPv6EndpointBehavior | | | | +-------+--------------------------------+ Table 1: New IPv6 SRH IEs in the "IPFIX Information Elements" Registry 5.1.1. srhFlagsIPv6 Name: srhFlagsIPv6 ElementID: TBD1 Description: The 8-bit flags defined in the SRH (Section 2 of Graf, et al. Expires 26 November 2023 [Page 7] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 [RFC8754]). Assigned flags and their meanings are provided in the "Segment Routing Header Flags" IANA registry. Abstract Data Type: unsigned8 Data Type Semantics: flags Additional Information: See the assignments in the "Segment Routing Header Flags" IANA registry at https://www.iana.org/assignments/ ipv6-parameters/ipv6-parameters.xhtml#segment-routing-header- flags. See also RFC8754 for the SRH specification. Reference: [RFC-to-be] 5.1.2. srhTagIPv6 Name: srhTagIPv6 ElementID: TBD2 Description: The 16-bit tag field defined in the SRH (Section 2 of [RFC8754]). A tag is used to mark a packet as part of a class or group of packets sharing the same set of properties. Abstract Data Type: unsigned16 Data Type Semantics: identifier Additional Information: See Section 2 of [RFC8754] for more details about the tag. Reference: [RFC-to-be] 5.1.3. srhSegmentIPv6 Name: srhSegmentIPv6 ElementID: TBD3 Description: The 128-bit IPv6 address that represents a SRv6 segment. Abstract Data Type: ipv6address Data Type Semantics: default Additional Information: Specified in Section 1 of [RFC8402] and mentioned in "Segment List" in Section 2 of [RFC8754]. Graf, et al. Expires 26 November 2023 [Page 8] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 Reference: [RFC-to-be] 5.1.4. srhActiveSegmentIPv6 Name: srhActiveSegmentIPv6 ElementID: TBD4 Description: The 128-bit IPv6 address that represents the active SRv6 segment. Abstract Data Type: ipv6address Data Type Semantics: default Additional Information: See Section 2 of [RFC8402] for the definition of active segment. Reference: [RFC-to-be] 5.1.5. srhSegmentIPv6BasicList Name: srhSegmentIPv6BasicList ElementID: TBD5 Description: The Ordered basicList [RFC6313] of zero or more 128-bit IPv6 addresses in the SRH that represents the SRv6 Segment List. As specified in Section 2 of [RFC8754], the Segment List is encoded starting from the last segment of the SR Policy. That is, the first element of the Segment List (Segment List[0]) contains the last segment of the SR Policy, the second element contains the penultimate segment of the SR Policy, and so on. Abstract Data Type: basicList Data Type Semantics: list Additional Information: See Section 2 of [RFC8754] for more details about the SRv6 Segment List. Reference: [RFC-to-be] 5.1.6. srhSegmentIPv6ListSection Name: srhSegmentIPv6ListSection ElementID: TBD6 Graf, et al. Expires 26 November 2023 [Page 9] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 Description: The SRH Segment List as defined in Section 2 of [RFC8754] as a series of octets in IPFIX. Abstract Data Type: octetArray Data Type Semantics: default Additional Information: See Section 2 of [RFC8754] for more details about the SRv6 Segment List. Reference: [RFC-to-be] 5.1.7. srhSegmentsIPv6Left Name: srhSegmentsIPv6Left ElementID: TBD7 Description: 8-bit unsigned integer defining the number of segments remaining to reach the end of the Segment List in the SRH. Abstract Data Type: unsigned8 Data Type Semantics: quantity Additional Information: Specified by the "Segments Left" field in Section 4.4 of [RFC8200] and mentioned in Section 2 of [RFC8754]). Reference: [RFC-to-be] 5.1.8. srhIPv6Section Name: srhIPv6Section Description: The SRH and its TLVs as defined in Section 2 of [RFC8754] as a series of octets in IPFIX. Abstract Data Type: octetArray Data Type Semantics: default Additional Information: See Section 2 of [RFC8754] for more details about the structure of an SRH. Reference: [RFC-to-be] Graf, et al. Expires 26 November 2023 [Page 10] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 5.1.9. srhIPv6ActiveSegmentType Name: srhIPv6ActiveSegmentType ElementID: TBD9 Description: The designator of the routing protocol or PCEP extension from where the active SRv6 segment has been learned from. Values for this Information Element are listed in the "IPFIX IPv6 SRH Segment type" subregistry, see [IANA-IPFIX]. Abstract Data Type: unsigned8 Data Type Semantics: identifier Additional Information: See the assigned types in [IPFIX IPv6 SRH Segment Type Subregistry]. Note to IANA: Please replace [IPFIX IPv6 SRH Segment Type Subregistry] with the URL of the IANA subregistry. Reference: [RFC-to-be] 5.1.10. srhSegmentIPv6LocatorLength Name: srhSegmentIPv6LocatorLength ElementID: TBD10 Description: The SRH segment IPv6 locator length specified as the number of significant bits. Together with srhSegmentIPv6 it enables the calculation of the SRv6 Locator. Abstract Data Type: unsigned8 Data Type Semantics: default Additional Information: See Section 3.1 of [RFC8986] for more details about the SID format. Reference: [RFC-to-be] 5.1.11. srhSegmentIPv6EndpointBehavior Name: srhSegmentIPv6EndpointBehavior ElementID: TBD11 Graf, et al. Expires 26 November 2023 [Page 11] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 Description: The 16-bit unsigned integer that represents a SRv6 Endpoint behavior as per Section 4 of [RFC8986]. Assigned values and their meanings are provided in the "SRV6 Endpoint Behavior" registry. Abstract Data Type: unsigned16 Data Type Semantics: identifier Additional Information: See the assigned behaviors at the "SRv6 Endpoint Behavior" registry available at https://www.iana.org/assignments/segment-routing/segment- routing.xhtml#srv6-endpoint-behaviors. See Section 4 of [RFC8986] for more details about the endpoint behaviors processing. Reference: [RFC-to-be] 5.2. New IPFIX IPv6 SRH Segment Type Subregistry This document requests IANA to create a new subregistry called "IPFIX IPv6 SRH Segment Type" under the "IPFIX Information Elements" registry [RFC7012] available at [IANA-IPFIX]. The allocation policy of this new subregistry is Expert Review (Section 4.5 of [RFC8126]). The designated experts for this registry should be familiar with SRH. The guidelines that are being followed by the designated experts for the IPFIX registry should be followed for this subregistry. In particular, criteria that should be applied by the designated experts include determining whether the proposed registration duplicates existing entries and whether the registration description is clear and fits the purpose of this registry. Within the review period, the designated experts will either approve or deny the registration request, communicating this decision to IANA. Denials should include an explanation and, if applicable, suggestions as to how to make the request successful. Initial values in the registry are defined in Table 2. Graf, et al. Expires 26 November 2023 [Page 12] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 +-------+--------------------+---------------------------------------+ | Value | Description | Additional Information | +-------+--------------------+---------------------------------------+ | TBD12 | Unknown | [RFC-to-be] | | | | | +-------+--------------------+---------------------------------------+ | TBD13 | Segment Routing | [RFC-to-be], | | | Policy | | +-------+--------------------+---------------------------------------+ | TBD14 | Path Computation | [RFC-to-be], | +-------+--------------------+---------------------------------------+ | TBD15 | OSPFv3 | [RFC-to-be],| +-------+--------------------+---------------------------------------+ | TBD16 | IS-IS | [RFC-to-be], | | | Segment Routing | | +-------+--------------------+---------------------------------------+ | TBD17 | BGP Segment | [RFC-to-be], | | | Routing Prefix-SID | | +-------+--------------------+---------------------------------------+ Table 2: "IPFIX IPv6 SRH Segment Type" Subregistry 6. Operational Considerations 6.1. SRv6 Segment List The zero or more 128-bit IPv6 addresses in the SRH [RFC8754] can be exported in two different ways, with two different IPFIX IEs: * srhSegmentIPv6BasicList * srhSegmentIPv6ListSection The srhSegmentIPv6BasicList encodes the SRv6 Segment List with a basicList, specified in the IPFIX Structured Data [RFC6313]. This encoding offers the advantage to the data collection that the different IPv6 addresses are already structured as a list, without the need of post-processing. However, this method requires some extra processing on the exporter, to realize the BasicList data mapping. The srhSegmentIPv6ListSection, on the other hand, encodes the list of IPv6 addresses as an octetArray. This doesn't impose any data flow manipulation on the exporter, facilitating the immediate export. However, the data collection MUST be able to decode the IPv6 Graf, et al. Expires 26 November 2023 [Page 13] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 addresses according to the SR specifications. Compared to the srhSegmentIPv6BasicList, the srhSegmentIPv6ListSection flow records length is slightly reduced. It is not expected that an exporter would support both srhSegmentIPv6BasicList and srhSegmentIPv6ListSection at the same time. 6.2. Compressed SRv6 Segment List Decomposition The SRv6 Segment List in the IPFIX IEs srhSegmentIPv6BasicList, srhSegmentIPv6ListSection and destinationIPv6Address could contain compressed-SID containers as described in [I-D.ietf-spring-srv6-srh-compression]. The SR Endpoint Flavors, described in Section 4 of [I-D.ietf-spring-srv6-srh-compression] defines new flavors for SID endpoint behaviors, and determine wherever the Segment List encoding is compressed, along with the flavor. The SID Locator as described in Section 3.1 of [RFC8986], determines the common most significant bits. By using described information from srhSegmentIPv6EndpointBehavior and srhSegmentIPv6LocatorLength the compressed-SID containers can be decoded at the data collection. 7. Acknowledgements The authors would like to thank Yao Liu, Eduard Vasilenko, Bruno Decraene, Mohamed Boucadair, Kamran Raza, Qin Wu, Jim Guichard, Tero Kivinen, Paul Aitken, Roman Danyliw, John Scudder, Eric Vyncke, Erik Kline, Lars Eggert and Andrew Alston for their review and valuable comments, and Paolo Lucente and Alex Huang Feng for the implementation and validation. 8. Implementation Status Note to the RFC-Editor: Please remove this section before publishing. 8.1. FD.io VPP INSA Lyon implemented the following IEs as part of a prototype in the FD.io VPP (Vector Packet Processing) platform: * srhActiveSegmentIPv6 * srhSegmentIPv6EndpointBehavior * srhSegmentsIPv6Left * srhFlagsIPv6 Graf, et al. Expires 26 November 2023 [Page 14] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 * srhTagIPv6 * srhSegmentIPv6ListSection * srhSegmentIPv6BasicList The open source code can be obtained here: [INSA-Lyon-VPP] and was validated at the IETF 115 hackathon. 8.2. Huawei VRP Huawei implemented the following IEs as part of a production implementation in the VRP platform: * srhActiveSegmentIPv6 * srhSegmentsIPv6Left * srhFlagsIPv6 * srhTagIPv6 * srhSegmentIPv6ListSection The implementation was validated at the IETF 115 hackathon. 8.3. Pmacct Data Collection Paolo Lucente implemented the decomposition of the IE srhSegmentIPv6ListSection as part of a a production implementation in the open source Network Telemetry data collection project pmacct. The source code can be obtained here: [Paolo-Lucente-Pmacct] and was validated at the IETF 115 hackathon. 9. Security Considerations There exists no extra security considerations regarding allocation of these new IPFIX IEs compared to [RFC7012]. The IEs described in this document export provider plane data metrics on how packets are being forwarded within a SRv6 network. Applications and operators using the IEs described in this document must evaluate the sensitivity of this information in their implementation context, and apply the data-at-rest storage guidance in Section 11.8 of [RFC7011] as appropriate. 10. References Graf, et al. Expires 26 November 2023 [Page 15] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 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, . [RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates, "Export of Structured Data in IP Flow Information Export (IPFIX)", RFC 6313, DOI 10.17487/RFC6313, July 2011, . [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, . [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, DOI 10.17487/RFC8126, June 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017, . [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, . 10.2. Informative References Graf, et al. Expires 26 November 2023 [Page 16] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 [I-D.ietf-lsr-ospfv3-srv6-extensions] Li, Z., Hu, Z., Talaulikar, K., and P. Psenak, "OSPFv3 Extensions for SRv6", Work in Progress, Internet-Draft, draft-ietf-lsr-ospfv3-srv6-extensions-11, 2 May 2023, . [I-D.ietf-pce-segment-routing-ipv6] Li, C., Negi, M. S., Sivabalan, S., Koldychev, M., Kaladharan, P., and Y. Zhu, "Path Computation Element Communication Protocol (PCEP) Extensions for Segment Routing leveraging the IPv6 dataplane", Work in Progress, Internet-Draft, draft-ietf-pce-segment-routing-ipv6-16, 6 March 2023, . [I-D.ietf-spring-srv6-srh-compression] Cheng, W., Filsfils, C., Li, Z., Decraene, B., and F. Clad, "Compressed SRv6 Segment List Encoding in SRH", Work in Progress, Internet-Draft, draft-ietf-spring-srv6-srh- compression-04, 31 March 2023, . [IANA-IPFIX] "IANA, "IP Flow Information Export (IPFIX) Entities"", . [INSA-Lyon-VPP] "INSA Lyon, FD.io VPP implementation", . [Paolo-Lucente-Pmacct] "Paolo Lucente, Pmacct open source Network Telemetry Data Collection", . [RFC7270] Yourtchenko, A., Aitken, P., and B. Claise, "Cisco- Specific Information Elements Reused in IP Flow Information Export (IPFIX)", RFC 7270, DOI 10.17487/RFC7270, June 2014, . [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, . Graf, et al. Expires 26 November 2023 [Page 17] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 [RFC8669] Previdi, S., Filsfils, C., Lindem, A., Ed., Sreekantiah, A., and H. Gredler, "Segment Routing Prefix Segment Identifier Extensions for BGP", RFC 8669, DOI 10.17487/RFC8669, December 2019, . [RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer, D., Matsushima, S., and Z. Li, "Segment Routing over IPv6 (SRv6) Network Programming", RFC 8986, DOI 10.17487/RFC8986, February 2021, . [RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov, A., and P. Mattes, "Segment Routing Policy Architecture", RFC 9256, DOI 10.17487/RFC9256, July 2022, . [RFC9352] Psenak, P., Ed., Filsfils, C., Bashandy, A., Decraene, B., and Z. Hu, "IS-IS Extensions to Support Segment Routing over the IPv6 Data Plane", RFC 9352, DOI 10.17487/RFC9352, February 2023, . Appendix A. IPFIX Encoding Examples This appendix represents three different encodings for the newly introduced IEs, for the example values in Table 3. The three different encodings use the following IEs, respectively: srhSegmentIPv6BasicList, srhSegmentIPv6ListSection, and srhIPv6Section. +-----+------+-----+----------------+--------------------------| | SRH | SRH | SRH | Active Segment | Segment List | | Nr | Flags| Tag | Type | | +-----+------+-----+----------------+--------------------------+ | 1 | 0 | 123 | IS-IS | 2001:db8::1, 2001:db8::2,| | | | | | 2001:db8::3 | +-----+------+-----+----------------+--------------------------+ | 2 | 0 | 456 | IS-IS | 2001:db8::4, 2001:db8::5 | +-----+------+-----+----------------+--------------------------+ | 3 | 0 | 789 | IS-IS | 2001:db8::6 | +-----+------+-----+----------------+--------------------------+ Table 3: Three Observed SRH headers and Their Associated Routing Protocol A.1. Three Observed SRH Headers and their Routing Protocol Graf, et al. Expires 26 November 2023 [Page 18] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 A.1.1. Template Record and Data Set with Segment Basic List With encoding in Figure 1, the examples in Table 3 are represented with the following IEs: “=>” is used to indicate which IE is mapped to a given information. * SR Flags => srhFlagsIPv6 (TBD1) * SR Tag => srhTagIPv6 (TBD2) * Active Segment Type => srhIPv6ActiveSegmentType (TBD9) * Segment List => srhSegmentIPv6BasicList (TBD5) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 2 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 256 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhFlagsIPv6 = TBD1 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhTagIPv6 = TBD2 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|srhActiveSegmentIPv... = TBD9| Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|srhSegmentIPv6BasicList= TBD5| Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Template Record with Basic List Encoding Format In this example, the Template ID is 256, which will be used in the Data Record. The field length for srhSegmentIPv6BasicList is 0xFFFF, which means the length of this IE is variable, and the actual length of this IE is indicated by the List Length field in the basicList format as per [RFC6313]. The data set is represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 256 | Length = 136 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhFlagsIPv6 | srhTagIPv6 = 123 | srhActiveSegme| | = 0 | | ntIPv...=TBD16| Graf, et al. Expires 26 November 2023 [Page 19] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | List Length = 53 |semantic= | | | |ordered | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhSegmentIPv6 = TBD3 | Field Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[0] = 2001:db8::1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[1] = 2001:db8::2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[2] = 2001:db8::3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhFlagsIPv6 | srhTagIPv6 = 456 | srhActiveSegme| | = 0 | | ntIPv...=TBD16| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | List Length = 37 |semantic= | | | |ordered | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhSegmentIPv6 = TBD3 | Field Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[0] = 2001:db8::4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[1] = 2001:db8::5 (16 bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Graf, et al. Expires 26 November 2023 [Page 20] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhFlagsIPv6 | srhTagIPv6 = 789 | srhActiveSegme| | = 0 | | ntIPv...=TBD16| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 255 | List Length = 21 |semantic= | | | |ordered | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhSegmentIPv6 = TBD3 | Field Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[0] = 2001:db8::6 ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Data Set Encoding Format for Basic List A.1.2. Template Record and Data Set with Segment List Section With encoding in Figure 3, the examples in Table 3 are represented with the following IEs: “=>” is used to indicate which IE is mapped to a given information. * SR Flags => srhFlagsIPv6 (TBD1) * SR Tag => srhTagIPv6 (TBD2) * Active Segment Type => srhIPv6ActiveSegmentType (TBD9) * Segment List => srhSegmentIPv6ListSection (TBD6) Graf, et al. Expires 26 November 2023 [Page 21] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 2 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 257 | Field Count = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhFlagsIPv6 = TBD1 | Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhTagIPv6 = TBD2 | Field Length = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|srhActiveSegmentIPv... = TBD9| Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhSegmentIPv6List | Field Length = 0xFFFF | | | Section=TBD6 | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Template Record with Segment List Section Encoding Format In this example, the Template ID is 257, which will be used in the Data Record. The field length for srhSegmentIPv6ListSection in the Template Record is 0xFFFF, which means that the length of this IE is variable: its actual length is encoded in the Data Set. Note that, with an actual length inferior to 255 in the Data Record example, the length field is encoded in 8 bits (Section 7 of [RFC7011]). The data can be represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 257 | Length = 116 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhFlagsIPv6 | srhTagIPv6 = 123 | srhActiveSegme| | = 0 | | ntIPv...=TBD16| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length = 48 | 2001:db8::1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | 2001:db8::2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | Graf, et al. Expires 26 November 2023 [Page 22] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | 2001:db8::3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | srhFlagsIPv6 | srhTagIPv6 = 456 | | | = 0 | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhActiveSegme| Length = 32 | 2001:db8::4 | | ntIPv...=TBD15| | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | 2001:db8::5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |srhFlagsIPv6=0 | srhTagIPv6... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | = 789 | srhActiveSegment | Length = 16 | | | IPv6Type=TBD16 | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2001:db8::6 ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Graf, et al. Expires 26 November 2023 [Page 23] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 Figure 4: Data Set Encoding Format for Segment List Section A.1.3. Template Record and Data Set with SRH Section With encoding in Figure 5, the examples in Table 3 are represented with the following IEs: “=>” is used to indicate which IE is mapped to a given information. * SR Flags + SR Tag + Segment List => srhIPv6Section (TBD8) * Active Segment Type => srhIPv6ActiveSegmentType (TBD9) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 2 | Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 258 | Field Count = 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhActiveSegmentIP... = TBD9| Field Length = 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| srhIPv6Section = TBD8 | Field Length = 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: Template Record with SRH Section Encoding Format In this example, the Template ID is 258, which will be used in the Data Record. The field length for srhIPv6Section in the Template Record is 0xFFFF, which means that the length of this IE is variable: its actual length is encoded in the Data Set. Note that, with an actual length inferior to 255 in the Data Record example, the length field is encoded in 8 bits (Section 7 of [RFC7011]). The data can be represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 258 | Length = (*) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhIPv6ActiveSegmentType = TBD16 | Length = (*) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Header | Hdr Ext Len | Routing Type | Segments Left | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Last Entry | Flags | Tag | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Graf, et al. Expires 26 November 2023 [Page 24] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 | Segment List[0] 2001:db8::1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[1] 2001:db8::2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[2] 2001:db8::3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Optional Type Length Value objects (variable) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhIPv6ActiveSegmentType = TBD16 | 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Header | Hdr Ext Len | Routing Type | Segments Left | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Last Entry | Flags | Tag | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[0] 2001:db8::4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[1] 2001:db8::5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Graf, et al. Expires 26 November 2023 [Page 25] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 ~ Optional Type Length Value objects (variable) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhIPv6ActiveSegmentType = TBD16 | 0xFFFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Next Header | Hdr Ext Len | Routing Type | Segments Left | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Last Entry | Flags | Tag | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Segment List[0] 2001:db8::6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Optional Type Length Value objects (variable) ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6: Data Set Encoding Format for SRH Section (*) The Length must be calculated to include the optional Type Length Value objects. A.2. Options Template Record and Data Set for SRv6 Segment End Point behavior and Locator Length This appendix provides an SRv6 EndPoint Bevahior Options Template example, for the values presented in Table 4. In the Options Template case, the srhActiveSegmentIPv6 Information Element is a Scope field +-------+-------------+-------------------------+----------------+ | Entry | SRH End | SRH End | SRH Segment | | Nr | Point IPv6 | Point Behavior | Locator Length | +-------+-------------+-------------------------+----------------+ | 1 | 2001:db8::1 | End [1] | 48 | +-------+-------------+-------------------------+----------------+ | 2 | 2001:db8::4 | End with NEXT-CSID [43] | 48 | +-------+-------------+-------------------------+----------------+ | 3 | 2001:db8::6 | End.DX6 [16] | 48 | +-------+-------------+-------------------------+----------------+ Table 4: Three Observed SRv6 Segment End Point Behaviors Graf, et al. Expires 26 November 2023 [Page 26] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 3 | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID 259 | Field Count = 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count = 1 |0| srhActiveSegmentIPv6 = TBD4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Field Length = 4 |0|srhSegmentEndpointBeh..=TBD11| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 1 |0|srhSegmentIPv6Lo.Length=TBD10| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Field Length = 4 | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7: Template Record with SRH Section Encoding Format In this example, the Template ID is 259, which will be used in the Data Record. The data set is represented as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SET ID = 259 | Length = 28 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2001:db8::1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | End [1] | 48 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2001:db8::4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | End with NEXT-CSID [43] | 48 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 2001:db8::6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | End.DX6 [16] | 48 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 8: Data Set Encoding Format for SRH Section Graf, et al. Expires 26 November 2023 [Page 27] Internet-Draft IPFIX Segment Routing over IPv6 May 2023 (*) The Length must be calculated to include the optional Type Length Value objects. Authors' Addresses Thomas Graf Swisscom Binzring 17 CH-8045 Zurich Switzerland Email: thomas.graf@swisscom.com Benoit Claise Huawei Email: benoit.claise@huawei.com Pierre Francois INSA-Lyon Lyon France Email: pierre.francois@insa-lyon.fr Graf, et al. Expires 26 November 2023 [Page 28]