Internet DRAFT - draft-ietf-opsawg-ipfix-srv6-srh
draft-ietf-opsawg-ipfix-srv6-srh
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
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Internet-Drafts are draft documents valid for a maximum of six months
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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
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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
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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
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* 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]).
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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].
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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:
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+-------+--------------------------------+
|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
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[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].
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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
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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]
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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
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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.
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+-------+--------------------+---------------------------------------+
| Value | Description | Additional Information |
+-------+--------------------+---------------------------------------+
| TBD12 | Unknown | [RFC-to-be] |
| | | |
+-------+--------------------+---------------------------------------+
| TBD13 | Segment Routing | [RFC-to-be], |
| | Policy | <xref target="RFC9256"/> |
+-------+--------------------+---------------------------------------+
| TBD14 | Path Computation | [RFC-to-be],<xref target=" |
| | Element | I-D.ietf-pce-segment-routing-ipv6"/> |
+-------+--------------------+---------------------------------------+
| TBD15 | OSPFv3 | [RFC-to-be],<xref target=" |
| | Segment Routing | I-D.ietf-lsr-ospfv3-srv6-extensions"/>|
+-------+--------------------+---------------------------------------+
| TBD16 | IS-IS | [RFC-to-be],<xref target="RFC9352"/> |
| | Segment Routing | |
+-------+--------------------+---------------------------------------+
| TBD17 | BGP Segment | [RFC-to-be], |
| | Routing Prefix-SID | <xref target="RFC8669"/> |
+-------+--------------------+---------------------------------------+
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
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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
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* 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
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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,
<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>.
10.2. Informative References
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[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,
<https://datatracker.ietf.org/doc/html/draft-ietf-lsr-
ospfv3-srv6-extensions-11>.
[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, <https://datatracker.ietf.org/doc/html/draft-
ietf-pce-segment-routing-ipv6-16>.
[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,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
srv6-srh-compression-04>.
[IANA-IPFIX]
"IANA, "IP Flow Information Export (IPFIX) Entities"",
<https://www.iana.org/assignments/ipfix/ipfix.xhtml>.
[INSA-Lyon-VPP]
"INSA Lyon, FD.io VPP implementation",
<https://github.com/network-analytics/vpp-srh-onpath-
telemetry>.
[Paolo-Lucente-Pmacct]
"Paolo Lucente, Pmacct open source Network Telemetry Data
Collection", <https://github.com/pmacct/pmacct>.
[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>.
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[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>.
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
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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|
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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)
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | 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 ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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~ 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
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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
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(*) 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
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