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diff --git a/doc/rfc/rfc9487.txt b/doc/rfc/rfc9487.txt new file mode 100644 index 0000000..d706155 --- /dev/null +++ b/doc/rfc/rfc9487.txt @@ -0,0 +1,1115 @@ + + + + +Internet Engineering Task Force (IETF) T. Graf +Request for Comments: 9487 Swisscom +Category: Standards Track B. Claise +ISSN: 2070-1721 Huawei + P. Francois + INSA-Lyon + November 2023 + + + Export of Segment Routing over IPv6 Information in IP Flow Information + Export (IPFIX) + +Abstract + + This document introduces new IP Flow Information Export (IPFIX) + Information Elements (IEs) to identify a set of information related + to Segment Routing over IPv6 (SRv6) 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 is an Internet Standards Track document. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Further information on + Internet Standards is available in Section 2 of RFC 7841. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + https://www.rfc-editor.org/info/rfc9487. + +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 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. Terminology + 3. New IPFIX IPv6 SRH Information Elements + 4. Sample Use Cases + 5. IANA Considerations + 5.1. IPFIX Information Elements Registry + 5.1.1. srhFlagsIPv6 + 5.1.2. srhTagIPv6 + 5.1.3. srhSegmentIPv6 + 5.1.4. srhActiveSegmentIPv6 + 5.1.5. srhSegmentIPv6BasicList + 5.1.6. srhSegmentIPv6ListSection + 5.1.7. srhSegmentsIPv6Left + 5.1.8. srhIPv6Section + 5.1.9. srhIPv6ActiveSegmentType + 5.1.10. srhSegmentIPv6LocatorLength + 5.1.11. srhSegmentIPv6EndpointBehavior + 5.2. New IPFIX IPv6 SRH Segment Type (Value 500) Subregistry + 6. Operational Considerations + 6.1. SRv6 Segment List + 6.2. Compressed SRv6 Segment List Decomposition + 7. Security Considerations + 8. References + 8.1. Normative References + 8.2. Informative References + Appendix A. IPFIX Encoding Examples + A.1. Three Observed SRH Headers and Their Routing Protocols + A.1.1. Template Record and Data Set with Segment Basic List + A.1.2. Template Record and Data Set with Segment List Section + A.1.3. Template Record and Data Set with SRH Section + A.2. Options Template Record and Data Set for SRv6 Segment + Endpoint Behavior and Locator Length + Acknowledgements + Authors' Addresses + +1. Introduction + + A dedicated Routing Extension Header, called "Segment Routing Header + (SRH)", is defined in [RFC8754] for use of Segment Routing over IPv6 + (SRv6) data plane. + + Also, three routing protocol extensions, OSPFv3 [OSPFV3-SRV6-EXT], + IS-IS [RFC9352], and BGP Prefix Segment Identifiers (Prefix-SIDs) + [RFC8669]; the Path Computation Element Communication Protocol (PCEP) + Extension [PCEP-SRV6-EXT]; and the 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 + + * 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 + The 8-bit Flags field defined in the SRH (Section 2 of [RFC8754]). + + srhTagIPv6 + 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. + + srhSegmentIPv6 + The 128-bit IPv6 address that represents an SRv6 segment. + + srhActiveSegmentIPv6 + The 128-bit IPv6 address that represents the active SRv6 segment. + + srhSegmentIPv6BasicList + 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. + + srhSegmentIPv6ListSection + The SRH Segment List as defined in Section 2 of [RFC8754] as a + series of octets in IPFIX. + + srhSegmentsIPv6Left + The 8-bit unsigned integer that defines 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 as mentioned in the SRH part of Section 2 of [RFC8754]. + + srhIPv6Section + The SRH and its TLVs as specified in Section 2 of [RFC8754] as a + series of octets in IPFIX. + + srhIPv6ActiveSegmentType + The designator of the routing protocol or PCEP extension where the + active SRv6 segment has been learned from. + + srhSegmentIPv6LocatorLength + The length of the SRH segment IPv6 locator specified as the number + of significant bits. Together with srhSegmentIPv6, it enables the + calculation of the SRv6 Locator. + + srhSegmentIPv6EndpointBehavior + The 16-bit unsigned integer that represents an SRv6 Endpoint + behavior as per Section 4 of [RFC8986]. + + 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 (496) or alternatively + srhSegmentIPv6ListSection (497), srhActiveSegmentIPv6 (495), + srhSegmentsIPv6Left (498), srhIPv6ActiveSegmentType (500), and + forwardingStatus (89) [RFC7270] [IANA-IPFIX] as well as some existing + counter information [IANA-IPFIX] provide answers to the following + questions (amongst others): + + * How many packets steered with an 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 + +5.1. IPFIX Information Elements Registry + + IANA has added the following new IEs to the "IPFIX Information + Elements" registry [RFC7012] at [IANA-IPFIX]: + + +===========+================================+ + | ElementID | Name | + +===========+================================+ + | 492 | srhFlagsIPv6 | + +-----------+--------------------------------+ + | 493 | srhTagIPv6 | + +-----------+--------------------------------+ + | 494 | srhSegmentIPv6 | + +-----------+--------------------------------+ + | 495 | srhActiveSegmentIPv6 | + +-----------+--------------------------------+ + | 496 | srhSegmentIPv6BasicList | + +-----------+--------------------------------+ + | 497 | srhSegmentIPv6ListSection | + +-----------+--------------------------------+ + | 498 | srhSegmentsIPv6Left | + +-----------+--------------------------------+ + | 499 | srhIPv6Section | + +-----------+--------------------------------+ + | 500 | srhIPv6ActiveSegmentType | + +-----------+--------------------------------+ + | 501 | srhSegmentIPv6LocatorLength | + +-----------+--------------------------------+ + | 502 | srhSegmentIPv6EndpointBehavior | + +-----------+--------------------------------+ + + Table 1: IPFIX Information Elements Registry + +5.1.1. srhFlagsIPv6 + + ElementID: 492 + Name: srhFlagsIPv6 + Abstract Data Type: unsigned8 + Data Type Semantics: flags + Description: The 8-bit Flags field defined in the SRH (Section 2 of + [RFC8754]). Assigned flags and their meanings are provided in the + "Segment Routing Header Flags" IANA registry. + Additional Information: See the assignments in the "Segment Routing + Header Flags" registry at <https://www.iana.org/assignments/ + ipv6-parameters>. See also [RFC8754] for the SRH specification. + Reference: RFC 9487 + +5.1.2. srhTagIPv6 + + ElementID: 493 + Name: srhTagIPv6 + Abstract Data Type: unsigned16 + Data Type Semantics: identifier + 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. + Additional Information: See Section 2 of [RFC8754] for more details + about the Tag. + Reference: RFC 9487 + +5.1.3. srhSegmentIPv6 + + ElementID: 494 + Name: srhSegmentIPv6 + Abstract Data Type: ipv6Address + Data Type Semantics: default + Description: The 128-bit IPv6 address that represents an SRv6 + segment. + Additional Information: Specified in Section 1 of [RFC8402] and + mentioned in "Segment List" in Section 2 of [RFC8754]. + Reference: RFC 9487 + +5.1.4. srhActiveSegmentIPv6 + + ElementID: 495 + Name: srhActiveSegmentIPv6 + Abstract Data Type: ipv6Address + Data Type Semantics: default + Description: The 128-bit IPv6 address that represents the active + SRv6 segment. + Additional Information: See Section 2 of [RFC8402] for the + definition of "active segment". + Reference: RFC 9487 + +5.1.5. srhSegmentIPv6BasicList + + ElementID: 496 + Name: srhSegmentIPv6BasicList + Abstract Data Type: basicList + Data Type Semantics: list + 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. + Additional Information: See Section 2 of [RFC8754] for more details + about the SRv6 Segment List. + Reference: RFC 9487 + +5.1.6. srhSegmentIPv6ListSection + + ElementID: 497 + Name: srhSegmentIPv6ListSection + Abstract Data Type: octetArray + Data Type Semantics: default + Description: The SRv6 Segment List as defined in Section 2 of + [RFC8754] as a series of octets in IPFIX. + Additional Information: See Section 2 of [RFC8754] for more details + about the SRv6 Segment List. + Reference: RFC 9487 + +5.1.7. srhSegmentsIPv6Left + + ElementID: 498 + Name: srhSegmentsIPv6Left + Abstract Data Type: unsigned8 + Data Type Semantics: quantity + Description: The 8-bit unsigned integer defining the number of + segments remaining to reach the end of the Segment List from the + SRH. + Additional Information: Specified by the "Segments Left" field in + Section 4.4 of [RFC8200] and mentioned in Section 2 of [RFC8754]. + Reference: RFC 9487 + +5.1.8. srhIPv6Section + + ElementID: 499 + Name: srhIPv6Section + Abstract Data Type: octetArray + Data Type Semantics: default + Description: The SRH and its TLVs as defined in Section 2 of + [RFC8754] as a series of octets in IPFIX. + Additional Information: See Section 2 of [RFC8754] for more details + about the structure of an SRH. + Reference: RFC 9487 + +5.1.9. srhIPv6ActiveSegmentType + + ElementID: 500 + Name: srhIPv6ActiveSegmentType + Abstract Data Type: unsigned8 + Data Type Semantics: identifier + Description: The designator of the routing protocol or PCEP + extension where the active SRv6 segment has been learned from. + Values for this Information Element are listed in the "IPFIX IPv6 + SRH Segment Type (Value 500)" subregistry. + Additional Information: See the assigned types in the "IPFIX IPv6 + SRH Segment (Value 500)" registry at + <https://www.iana.org/assignments/ipfix>. + Reference: RFC 9487 + +5.1.10. srhSegmentIPv6LocatorLength + + ElementID: 501 + Name: srhSegmentIPv6LocatorLength + Data Type Semantics: default + Description: The length of the SRH segment IPv6 locator specified as + the number of significant bits. Together with srhSegmentIPv6, it + enables the calculation of the SRv6 Locator. + Additional Information: See Section 3.1 of [RFC8986] for more + details about the SID format. + Reference: RFC 9487 + +5.1.11. srhSegmentIPv6EndpointBehavior + + ElementID: 502 + Name: srhSegmentIPv6EndpointBehavior + Abstract Data Type: unsigned16 + Data Type Semantics: identifier + Description: The 16-bit unsigned integer that represents an SRv6 + Endpoint behavior as per Section 4 of [RFC8986]. Assigned values + and their meanings are provided in the "SRv6 Endpoint Behaviors" + registry. + Additional Information: See the assigned behaviors in the "SRv6 + Endpoint Behaviors" registry at <https://www.iana.org/assignments/ + segment-routing>. See Section 4 of [RFC8986] for more details + about the processing of endpoint behaviors. + Reference: RFC 9487 + +5.2. New IPFIX IPv6 SRH Segment Type (Value 500) Subregistry + + IANA has created a new subregistry called "IPFIX IPv6 SRH Segment + Type (Value 500)" under the "IPFIX Information Elements" registry + [RFC7012] 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 Information Elements" 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. + + +=======+==========================+=============================+ + | Value | Description | Reference | + +=======+==========================+=============================+ + | 0 | Unknown | RFC 9487 | + +-------+--------------------------+-----------------------------+ + | 1 | Segment Routing Policy | RFC 9487, [RFC9256] | + +-------+--------------------------+-----------------------------+ + | 2 | Path Computation Element | RFC 9487, [PCEP-SRV6-EXT] | + +-------+--------------------------+-----------------------------+ + | 3 | OSPFv3 Segment Routing | RFC 9487, [OSPFV3-SRV6-EXT] | + +-------+--------------------------+-----------------------------+ + | 4 | IS-IS Segment Routing | RFC 9487, [RFC9352] | + +-------+--------------------------+-----------------------------+ + | 5 | BGP Segment Routing | RFC 9487, [RFC8669] | + | | Prefix-SID | | + +-------+--------------------------+-----------------------------+ + + Table 2: IPFIX IPv6 SRH Segment Type (Value 500) 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 is an advantage for data collection since 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 + 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 [SRV6-SRH-COM]. The SR + Endpoint Flavors, as described in Section 4 of [SRV6-SRH-COM], define + 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. Security Considerations + + There are no additional 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 an 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. + +8. References + +8.1. 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>. + + [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, + <https://www.rfc-editor.org/info/rfc6313>. + + [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, + <https://www.rfc-editor.org/info/rfc7011>. + + [RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model + for IP Flow Information Export (IPFIX)", RFC 7012, + DOI 10.17487/RFC7012, September 2013, + <https://www.rfc-editor.org/info/rfc7012>. + + [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, + <https://www.rfc-editor.org/info/rfc8126>. + + [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>. + + [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 + (IPv6) Specification", STD 86, RFC 8200, + DOI 10.17487/RFC8200, July 2017, + <https://www.rfc-editor.org/info/rfc8200>. + + [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, + <https://www.rfc-editor.org/info/rfc8754>. + +8.2. Informative References + + [IANA-IPFIX] + IANA, "IP Flow Information Export (IPFIX) Entities", + <https://www.iana.org/assignments/ipfix>. + + [OSPFV3-SRV6-EXT] + Li, Z., Hu, Z., Talaulikar, K., Ed., and P. Psenak, + "OSPFv3 Extensions for SRv6", Work in Progress, Internet- + Draft, draft-ietf-lsr-ospfv3-srv6-extensions-15, 21 June + 2023, <https://datatracker.ietf.org/doc/html/draft-ietf- + lsr-ospfv3-srv6-extensions-15>. + + [PCEP-SRV6-EXT] + Li, C., Kaladharan, P., Sivabalan, S., Koldychev, M., 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-ipv6-20, 8 September 2023, + <https://datatracker.ietf.org/doc/html/draft-ietf-pce- + segment-routing-ipv6-20>. + + [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, + <https://www.rfc-editor.org/info/rfc7270>. + + [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, <https://www.rfc-editor.org/info/rfc8402>. + + [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, + <https://www.rfc-editor.org/info/rfc8669>. + + [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, + <https://www.rfc-editor.org/info/rfc8986>. + + [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, + <https://www.rfc-editor.org/info/rfc9256>. + + [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, <https://www.rfc-editor.org/info/rfc9352>. + + [SRV6-SRH-COM] + Cheng, W., Ed., Filsfils, C., Li, Z., Decraene, B., and F. + Clad, Ed., "Compressed SRv6 Segment List Encoding", Work + in Progress, Internet-Draft, draft-ietf-spring-srv6-srh- + compression-09, 23 October 2023, + <https://datatracker.ietf.org/doc/html/draft-ietf-spring- + srv6-srh-compression-09>. + +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 Nr | SRH | SRH | Active | Segment List | + | | Flags | Tag | Segment Type | | + +========+=======+=====+==============+==========================+ + | 1 | 0 | 123 | IS-IS [4] | 2001:db8::1, | + | | | | | 2001:db8::2, 2001:db8::3 | + +--------+-------+-----+--------------+--------------------------+ + | 2 | 0 | 456 | IS-IS [4] | 2001:db8::4, 2001:db8::5 | + +--------+-------+-----+--------------+--------------------------+ + | 3 | 0 | 789 | IS-IS [4] | 2001:db8::6 | + +--------+-------+-----+--------------+--------------------------+ + + Table 3: Three Observed SRH Headers and Their Associated + Routing Protocols + +A.1. Three Observed SRH Headers and Their Routing Protocols + +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, where "=>" is used to indicate which IE is + mapped to given information: + + * SRH Flags => srhFlagsIPv6 (492) + + * SRH Tag => srhTagIPv6 (493) + + * Active Segment Type => srhIPv6ActiveSegmentType (500) + + * Segment List => srhSegmentIPv6BasicList (496) + + 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 = 492 | Field Length = 1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0| srhTagIPv6 = 493 | Field Length = 2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0|srhIPv6ActiveSegmentType= 500| Field Length = 1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0|srhSegmentIPv6BasicList = 496| 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 |srhIPv6Active | + | = 0 | |SegmentType= 4| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 255 | List Length = 53 |semantic= | + | | |ordered | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhSegmentIPv6 = 494 | Field Length = 16 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Segment List[0] = 2001:db8::1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Segment List[1] = 2001:db8::2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Segment List[2] = 2001:db8::3 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhFlagsIPv6 | srhTagIPv6 = 456 | srhIPv6Active | + | = 0 | | SegmentType= 4| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 255 | List Length = 37 |semantic= | + | | |ordered | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhSegmentIPv6 = 494 | Field Length = 16 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Segment List[0] = 2001:db8::4 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Segment List[1] = 2001:db8::5 (16 bytes) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhFlagsIPv6 | srhTagIPv6 = 789 | srhIPv6Active | + | = 0 | | SegmentType= 4| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 255 | List Length = 21 |semantic= | + | | |ordered | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhSegmentIPv6 = 494 | 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, where "=>" is used to indicate which IE is + mapped to given information: + + * SRH Flags => srhFlagsIPv6 (492) + + * SRH Tag => srhTagIPv6 (493) + + * Active Segment Type => srhIPv6ActiveSegmentType (500) + + * Segment List => srhSegmentIPv6ListSection (497) + + 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 = 492 | Field Length = 1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0| srhTagIPv6 = 493 | Field Length = 2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0|srhIPv6ActiveSegmentType= 500| Field Length = 1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0|srhSegmentIPv6ListSection=497| Field Length = 0xFFFF | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + 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 | srhIPv6Active | + | = 0 | | SegmentType= 4| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Length = 48 | 2001:db8::1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | 2001:db8::2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | 2001:db8::3 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | srhFlagsIPv6 | srhTagIPv6 = 456 | + | | = 0 | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhIPv6Active | Length = 32 | 2001:db8::4 | + | SegmentType= 4| | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | 2001:db8::5 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... |srhFlagsIPv6=0 | srhTagIPv6 = | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 789 | srhIPv6ActiveSegmentType = 4 | Length = 16 | + | | | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 2001:db8::6 ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + 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, where "=>" is used to indicate which IE is + mapped to given information: + + * SRH Flags + SRH Tag + Segment List => srhIPv6Section (499) + + * Active Segment Type => srhIPv6ActiveSegmentType (500) + + 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|srhIPv6ActiveSegmentType= 500| Field Length = 1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |0| srhIPv6Section = 499 | 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 = 4 | Length = (*) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Next Header | Hdr Ext Len | Routing Type | Segments Left | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Last Entry | Flags | Tag | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 2001:db8::1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 2001:db8::2 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 2001:db8::3 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ~ Optional Type Length Value objects (variable) ~ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhIPv6ActiveSegmentType = 4 | 0xFFFF | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Next Header | Hdr Ext Len | Routing Type | Segments Left | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Last Entry | Flags | Tag | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 2001:db8::4 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 2001:db8::5 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ~ Optional Type Length Value objects (variable) ~ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhIPv6ActiveSegmentType = 4 | 0xFFFF | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Next Header | Hdr Ext Len | Routing Type | Segments Left | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Last Entry | Flags | Tag | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | 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 Endpoint + Behavior and Locator Length + + This appendix provides an SRv6 Endpoint Behavior Options Template + example, for the values presented in Table 4. In the Options + Template case, the srhActiveSegmentIPv6 IE is a Scope field. + + +==========+===================+================+================+ + | Entry Nr | SRH Endpoint IPv6 | SRH Endpoint | SRH Segment | + | | | Behavior | Locator Length | + +==========+===================+================+================+ + | 1 | 2001:db8::1 | End [1] | 48 | + +----------+-------------------+----------------+----------------+ + | 2 | 2001:db8::4 | End with NEXT- | 48 | + | | | CSID [43] | | + +----------+-------------------+----------------+----------------+ + | 3 | 2001:db8::6 | End.DX6 [16] | 48 | + +----------+-------------------+----------------+----------------+ + + Table 4: Three Observed SRv6 Segment Endpoint Behaviors + + 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 = 495 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Scope 1 Field Length = 4 |0|srhSegmentIPv6End.Behav = 502| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Field Length = 1 |0|srhSegmentIPv6Lo.Length = 501| + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Field Length = 4 | Padding | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Figure 7: Segment Endpoint Behavior Options Template Record + + 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 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhActiveSegmentIPv6 = 2001:db8::1 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |srhSegmentIPv6EndpointBehavior |srhSegmentIPv6LocatorLength= 48| + |= End [1] | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhActiveSegmentIPv6 = 2001:db8::4 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |srhSegmentIPv6EndpointBehavior |srhSegmentIPv6LocatorLength= 48| + |= End with NEXT-CSID [43] | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | srhActiveSegmentIPv6 = 2001:db8::6 | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + |srhSegmentIPv6EndpointBehavior |srhSegmentIPv6LocatorLength= 48| + |= End.DX6 [16] | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Figure 8: Data Set Encoding Format for Segment Endpoint Behaviors + + (*) The Length must be calculated to include the optional Type Length + Value objects. + +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, Éric Vyncke, Erik + Kline, Lars Eggert, and Andrew Alston for their reviews and valuable + comments. And thank you to Paolo Lucente and Alex Huang Feng for the + implementation and validation. + +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 |