Network Working Group                                            T. Graf
Internet-Draft                                                  Swisscom
Intended status: Informational                           15 January 2022
Expires: 19 July 2022


             Export of Segment Routing IPv6 Information in
                   IP Flow Information Export (IPFIX)
                  draft-tgraf-opsawg-ipfix-srv6-srh-00

Abstract

   This document introduces new IP Flow Information Export (IPFIX) code
   points to identify which traffic is being forwarded with which
   Segemnt Routing Header dimensions based on which SRv6 control plane
   protocol.

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   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 19 July 2022.

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   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   provided without warranty as described in the Revised BSD License.




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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  IPFIX Information Elements  . . . . . . . . . . . . . . . . .   2
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Appendix A.  IPFIX Encoding Example . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   A new type of Routing Extension Header called Segment Routing Header
   (SRH) is defined by [RFC8754] which is used for applying Segment
   Routing (SR) on the IPv6 data plane.

   Three routing protocol extensions, OSPFv3 Extensions
   [I-D.li-lsr-ospfv3-srv6-extensions], IS-IS Extensions
   [I-D.ietf-lsr-isis-srv6-extensions], BGP Prefix Segment Identifiers
   (Prefix-SIDs) [I-D.ietf-bess-srv6-services] and one Path Computation
   Element Communication Protocol (PCEP) Extension
   [I-D.ietf-pce-segment-routing-ipv6] have been defined to be able to
   propagate Segment Identifiers (SIDs) for the IPv6 data plane.

   This document defines five new IPFIX Information Elements (IEs) and
   two new subregistries within the "IPFIX Information Elements"
   registry [RFC7012] for the new SRH dimensions and routing protocol
   and PCEP extensions.

2.  IPFIX Information Elements

   This section defines and describes the new IPFIX IEs.

   ipv6SRHFlags
      8-bit flags defined in the SRH.

   ipv6SRHTag
      16-bit tag field defined in the SRH that marks a packet as part of
      a class or group of packets sharing the same set of properties.

   ipv6SRHSegment
      128-bit IPv6 address that represents an SRv6 segment.





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   ipv6SRHSegmentList
      Ordered basicList of zero or more 128-bit IPv6 addresses in the
      SRH that represents the SRv6 segment list.  The Segment List is
      encoded starting from the last segment of the SR Policy.

   ipv6SRHSegmentType
      Name of the routing protocol or PCEP extension from where last
      SRv6 segment has been learned from.

3.  Use Cases

   By using ipv6SRHSegmentList(TBD5), ipv6SRHSegment1Type(TBD6) and
   forwardingStatus(89) it is possible to identify

   *  how many packets are forwarded or dropped

   *  if dropped, for which reasons, and

   *  infer control plane protocol for the last segment

   *  and the SRv6 segment list on every hop.

4.  IANA Considerations

   This document requests IANA to create new IEs and two new subregistry
   called ""IPFIX IPv6 SRH Flags (TBD1)" and IPFIX IPv6 SRH Segment type
   (TBD5)" under the "IPFIX Information Elements" registry [RFC7012]
   available at [IANA-IPFIX] and assign the following code points.























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   +--------+-------------------+------------+-----------+-------------+
   | Element|       Name        |  Abstract  | Data Type |  Reference  |
   |   ID   |                   |  Data Type | Semantics |             |
   +--------+-------------------+------------+-------------------------+
   | TBD1   | ipv6SRHFlag       | unsigned8  | flags     | [RFC-to-be],|
   |        |                   |            |           | RFC8754     |
   +--------+-------------------+------------+-------------------------+
   | TBD2   | ipv6SRHTag        | unsigned16 | identifier| [RFC-to-be],|
   |        |                   |            |           | RFC8754     |
   +--------+-------------------+------------+-------------------------+
   | TBD3   | ipv6SRHSegment    | ipv6address| default   | [RFC-to-be],|
   |        |                   |            |           | RFC8754     |
   +--------+-------------------+------------+-------------------------+
   | TBD4   | ipv6SRHSegmentList| basiclist  | list      | [RFC-to-be],|
   |        |                   |            |           | RFC8754     |
   +--------+-------------------+------------+-------------------------+
   | TBD5   | ipv6SRHSegmentType| unsigned8  | identifier| [RFC-to-be] |
   +--------+-------------------+------------+-------------------------+

     Table 1: Creates IEs in the "IPFIX Information Elements" registry

   +--------+-------------------+--------------------------------------+
   | Value  |    Description    |              Reference               |
   +--------+-------------------+--------------------------------------+
   | 0-7    | Unassigned        |                                      |
   +--------+-------------------+--------------------------------------+

         Table 2: Creates "IPFIX IPv6 SRH Flags (TBD1)" subregistry























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   +-------+--------------------+--------------------------------------+
   | Value |     Description    |              Reference               |
   +-------+--------------------+--------------------------------------+
   | TBD6  | Unknown            | [RFC-to-be]                          |
   |       |                    |                                      |
   +-------+--------------------+--------------------------------------+
   | TBD7  | Path Computation   | [RFC-to-be],                         |
   |       | Element            | draft-ietf-pce-segment-routing-ipv6  |
   +-------+--------------------+--------------------------------------+
   | TBD8  | OSPFv3             | [RFC-to-be],                         |
   |       | Segment Routing    | draft-li-ospf-ospfv3-srv6-extensions |
   +-------+--------------------+--------------------------------------+
   | TBD9  | IS-IS              | [RFC-to-be]                          |
   |       | Segment Routing    | draft-ietf-lsr-isis-srv6-extensions  |
   +-------+--------------------+--------------------------------------+
   | TBD10 | BGP Segment        | [RFC-to-be],                         |
   |       | Routing Prefix-SID | draft-ietf-bess-srv6-services        |
   +-------+--------------------+--------------------------------------+

     Table 3: Creates "IPFIX IPv6 SRH Segment type (TBD5)" subregistry

   Note to the RFC-Editor:

   *  Please replace TBD1 - TBD10 with the values allocated by IANA

   *  Please replace the [RFC-to-be] with the RFC number assigned to
      this document

5.  Security Considerations

   There exists no significant extra security considerations regarding
   the allocation of these new IPFIX IEs compared to [RFC7012].

6.  Acknowledgements

   TBD

7.  References

7.1.  Normative References

   [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>.






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   [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>.

7.2.  Informative References

   [I-D.ietf-bess-srv6-services]
              Dawra, G., Filsfils, C., Talaulikar, K., Raszuk, R.,
              Decraene, B., Zhuang, S., and J. Rabadan, "SRv6 BGP based
              Overlay Services", Work in Progress, Internet-Draft,
              draft-ietf-bess-srv6-services-08, 10 November 2021,
              <https://www.ietf.org/archive/id/draft-ietf-bess-srv6-
              services-08.txt>.

   [I-D.ietf-lsr-isis-srv6-extensions]
              Psenak, P., Filsfils, C., Bashandy, A., Decraene, B., and
              Z. Hu, "IS-IS Extensions to Support Segment Routing over
              IPv6 Dataplane", Work in Progress, Internet-Draft, draft-
              ietf-lsr-isis-srv6-extensions-18, 20 October 2021,
              <https://www.ietf.org/archive/id/draft-ietf-lsr-isis-srv6-
              extensions-18.txt>.

   [I-D.ietf-pce-segment-routing-ipv6]
              Li, C., Negi, M., Sivabalan, S., Koldychev, M.,
              Kaladharan, P., and Y. Zhu, "PCEP Extensions for Segment
              Routing leveraging the IPv6 data plane", Work in Progress,
              Internet-Draft, draft-ietf-pce-segment-routing-ipv6-11, 10
              January 2022, <https://www.ietf.org/internet-drafts/draft-
              ietf-pce-segment-routing-ipv6-11.txt>.

   [I-D.li-lsr-ospfv3-srv6-extensions]
              Li, Z., Hu, Z., Cheng, D., Talaulikar, K., and P. Psenak,
              "OSPFv3 Extensions for SRv6", Work in Progress, Internet-
              Draft, draft-li-lsr-ospfv3-srv6-extensions-00, 15 January
              2020, <https://www.ietf.org/archive/id/draft-li-lsr-
              ospfv3-srv6-extensions-00.txt>.

   [IANA-IPFIX]
              "IANA, "IP Flow Information Export (IPFIX) Entities"",
              <https://www.iana.org/assignments/ipfix/ipfix.xhtml>.

   [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>.





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Appendix A.  IPFIX Encoding Example

   In this section an example is provided to show the encoding format
   for the newly introduced IEs.

   +-----+------+-----+--------+---------------------------------------|
   | SRH | SRH  | SRH | 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 4: 3 observed SRH headers and their routing protocol

A.1.  Template Record

       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 = 41             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      Template ID = 256        |      Field Count = 4          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|     ipv6SRHFlags = TBD2     |      Field Length = 1         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|      ipv6SRHTag = TBD3      |      Field Length = 2         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|  ipv6SRHSegmentType = TBD6  |      Field Length = 1         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|    ipv6SRHSegment = TBD4    |      Field Length = 16        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|  ipv6SRHSegmentList = TBD5  |      Field Length = 0xFFFF    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Table 4: Template Record Encoding Format


   In this example, the Template ID is 256, which will be used in the
   Data Record.  The field length for ipv6SRHSegmentList 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].





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A.2.  Data Set

   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        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | ipv6SRHFlags  |        ipv6SRHTag = 123       | ipv6SRHSegment|
      | = 0           |                               | Type = TBD9   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      255      |        List Length = 53       |semantic=      |
      |               |                               |ordered        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Segment List[0] = 2001:db8::1  (16 bytes)         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Segment List[1] = 2001:db8::2  (16 bytes)         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Segment List[2] = 2001:db8::3  (16 bytes)         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | ipv6SRHFlags  |        ipv6SRHTag = 456       | ipv6SRHSegment|
      | = 0           |                               | Type = TBD9   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      255      |        List Length = 37       |semantic=      |
      |               |                               |ordered        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Segment List[0] = 2001:db8::4  (16 bytes)         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Segment List[1] = 2001:db8::5  (16 bytes)         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | ipv6SRHFlags  |        ipv6SRHTag = 789       | ipv6SRHSegment|
      | = 0           |                               | Type = TBD9   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      255      |        List Length = 21       |semantic=      |
      |               |                               |ordered        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     ipv6SRHSegment = TBD4     |        Field Length = 16      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Segment List[0] = 2001:db8::6  (16 bytes)         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Table 5: Data Set Encoding Format




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Author's Address

   Thomas Graf
   Swisscom
   Binzring 17
   CH-8045 Zurich
   Switzerland

   Email: thomas.graf@swisscom.com










































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