Network Working Group

Internet Engineering Task Force (IETF)                           T. Graf
Internet-Draft
Request for Comments: 9160                                      Swisscom
Intended status:
Category: Informational                         18 September                                    December 2021
Expires: 22 March 2022
ISSN: 2070-1721

    Export of MPLS Segment Routing Label Type Information in IP Flow
                       Information Export (IPFIX)
             draft-ietf-opsawg-ipfix-mpls-sr-label-type-11

Abstract

   This document introduces new IP Flow Information Export (IPFIX) code
   points to identify which traffic is being forwarded based on which
   MPLS control plane protocol is used within a Segment Routing domain.
   In particular, this document defines five code points for the IPFIX
   mplsTopLabelType Information Element for PCE, Path Computation Element
   (PCE), IS-IS, OSPFv2, OSPFv3, and BGP MPLS Segment Routing
   extensions.

Status of This Memo

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   This Internet-Draft will expire on 22 March 2022.
   https://www.rfc-editor.org/info/rfc9160.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  MPLS Segment Routing Top Label Type . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgements
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Four routing protocol extensions, extensions -- OSPFv2 Extensions [RFC8665],
   OSPFv3 Extensions [RFC8666], IS-IS Extensions [RFC8667], and BGP
   Prefix Segment Identifiers (Prefix-SIDs) [RFC8669] -- and one Path
   Computation Element Communication Protocol (PCEP) Extension [RFC8664]
   have been defined to be able to propagate Segment Routing (SR) labels
   for the MPLS data plane [RFC8660].

   Also, [I-D.ali-spring-sr-traffic-accounting] [SR-Traffic-Accounting] describes how IP Flow Information
   Export (IPFIX) [RFC7012] can be leveraged in dimensional data
   modelling
   modeling to account for traffic to MPLS SR label dimensions within a
   Segment Routing domain.

   In [RFC7012], the Information Element (IE) mplsTopLabelType(46)
   identifies which MPLS control plane protocol allocated the top-of-
   stack label in the MPLS label stack.  Per Section 7.2 of [RFC7012]
   creates [RFC7012],
   the "IPFIX MPLS label type (Value 46)" subregistry [IANA-IPFIX] was
   created, where new MPLS label type entries should be added.  This
   document defines new code points to address typical use cases that
   are discussed in Section 2.

2.  MPLS Segment Routing Top Label Type

   By introducing five new code points to the IPFIX IE
   mplsTopLabelType(46) for PCE, Path Computation Element (PCE), IS-IS,
   OSPFv2, OSPFv3 OSPFv3, and BGP Prefix-
   SID, Prefix-SIDs, it is possible to identify which
   traffic is being forwarded based upon which MPLS SR control plane
   protocol is in use.

   A typical use case is to monitor MPLS control plane migrations from
   LDP to IS-IS or OSPF Segment Routing.  Such a migration can be done
   node by node as described in Appendix A of [RFC8661].

   Another use case is to monitor MPLS control plane migrations from
   dynamic BGP labels [RFC8277] to BGP Prefix-SIDs [RFC8669].  For
   example, the motivation for, and benefits for of, such a migration in large-
   scale
   large-scale data centers are described in [RFC8670].

   Both use cases can be verified by using mplsTopLabelType(46),
   mplsTopLabelIPv4Address(47), mplsTopLabelIPv6Address(140),
   mplsTopLabelStackSection(70)
   mplsTopLabelStackSection(70), and forwardingStatus(89) IEs to infer

   *  how many packets are forwarded or dropped

   *  if packets are dropped, for which reasons, and

   *  the MPLS provider edge loopback address and label protocol

   By looking at the MPLS label value itself, it is not always clear as to
   which label protocol it belongs.  This is because they may share the
   same label allocation range.  This is, for example, the case for
   IGP-Adjacency IGP-
   Adjacency SIDs, LDP LDP, and dynamic BGP labels.

3.  IANA Considerations

   This document requests

   IANA to allocate has allocated the following code points in the existing subregistry "IPFIX MPLS label
   type (Value 46)" under subregistry within the "IPFIX Information Elements"
   registry [RFC7012] available at [RFC7012].  See [IANA-IPFIX].

      +-------+--------------------------------+----------------------+

      +=======+================================+====================+
      | Value | Description                    | Reference          |
      +-------+--------------------------------+----------------------+
      +=======+================================+====================+
      | TBD1 6     | Path Computation Element       | [RFC-to-be], RFC8664 RFC 9160, RFC 8664 |
      +-------+--------------------------------+----------------------+
      +-------+--------------------------------+--------------------+
      | TBD2 7     | OSPFv2 Segment Routing         | [RFC-to-be], RFC8665 RFC 9160, RFC 8665 |
      +-------+--------------------------------+----------------------+
      +-------+--------------------------------+--------------------+
      | TBD3 8     | OSPFv3 Segment Routing         | [RFC-to-be], RFC8666 RFC 9160, RFC 8666 |
      +-------+--------------------------------+----------------------+
      +-------+--------------------------------+--------------------+
      | TBD4 9     | IS-IS Segment Routing          | [RFC-to-be], RFC8667 RFC 9160, RFC 8667 |
      +-------+--------------------------------+----------------------+
      +-------+--------------------------------+--------------------+
      | TBD5 10    | BGP Segment Routing Prefix-SID | [RFC-to-be], RFC8669 RFC 9160, RFC 8669 |
      +-------+--------------------------------+----------------------+
      +-------+--------------------------------+--------------------+

           Table 1: Updates to "IPFIX MPLS label type (Value 46)" subregistry

   Note to the RFC-Editor:

   *  Please replace TBD1 - TBD5 with the values allocated by IANA

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

   References to
      this document

   Note IANA:

   *  Suggest RFCs 4364, 4271, and 5036 have been added to move the existing RFC references
   "Reference" column in the additional
      information column of IE mplsTopLabelType(46) to reference column "IPFIX MPLS label type (Value 46)"
   subregistry [IANA-IPFIX] for codepoint code points 3, 4 4, and 5. 5, respectively.
   Previously, these references appeared in the "Additional Information"
   column for mplsTopLabelType(46) in the "IPFIX Information Elements"
   registry [IANA-IPFIX].

4.  Operational Considerations

   In the IE mplsTopLabelType(46), the BGP code point 4 refers to the label
   value in the MP_REACH_NLRI path attribute described in Section 2 of
   [RFC8277], while the BGP Segment Routing Prefix-SID code point TBD5 10
   corresponds to the label index value in the Label-Index TLV described
   in Section 3.1 of [RFC8669].  These values are thus used for those
   distinct purposes.

5.  Security Considerations

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

7.

6.  References

7.1.

6.1.  Normative References

   [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.

6.2.  Informative References

   [I-D.ali-spring-sr-traffic-accounting]
              Filsfils, C., Talaulikar, K., Sivabalan, S., Horneffer,
              M., Raszuk, R., Litkowski, S., Voyer, D., and R. Morton,
              "Traffic Accounting in Segment Routing Networks", Work in
              Progress, Internet-Draft, draft-ali-spring-sr-traffic-
              accounting-05, 12 April 2021,
              <https://www.ietf.org/archive/id/draft-ali-spring-sr-
              traffic-accounting-05.txt>.

   [IANA-IPFIX]
              "IANA, IPFIX
              IANA, "IPFIX MPLS label type (Value 46)",
              <https://www.iana.org/assignments/ipfix/ipfix.xhtml#ipfix-
              mpls-label-type>.
              <https://www.iana.org/assignments/ipfix/>.

   [RFC8277]  Rosen, E., "Using BGP to Bind MPLS Labels to Address
              Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017,
              <https://www.rfc-editor.org/info/rfc8277>.

   [RFC8660]  Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing with the MPLS Data Plane", RFC 8660,
              DOI 10.17487/RFC8660, December 2019,
              <https://www.rfc-editor.org/info/rfc8660>.

   [RFC8661]  Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S.,
              Decraene, B., and S. Litkowski, "Segment Routing MPLS
              Interworking with LDP", RFC 8661, DOI 10.17487/RFC8661,
              December 2019, <https://www.rfc-editor.org/info/rfc8661>.

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
              DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

   [RFC8665]  Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler,
              H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
              Extensions for Segment Routing", RFC 8665,
              DOI 10.17487/RFC8665, December 2019,
              <https://www.rfc-editor.org/info/rfc8665>.

   [RFC8666]  Psenak, P., Ed. and S. Previdi, Ed., "OSPFv3 Extensions
              for Segment Routing", RFC 8666, DOI 10.17487/RFC8666,
              December 2019, <https://www.rfc-editor.org/info/rfc8666>.

   [RFC8667]  Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
              Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
              Extensions for Segment Routing", RFC 8667,
              DOI 10.17487/RFC8667, December 2019,
              <https://www.rfc-editor.org/info/rfc8667>.

   [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>.

   [RFC8670]  Filsfils, C., Ed., Previdi, S., Dawra, G., Aries, E., and
              P. Lapukhov, "BGP Prefix Segment in Large-Scale Data
              Centers", RFC 8670, DOI 10.17487/RFC8670, December 2019,
              <https://www.rfc-editor.org/info/rfc8670>.

6.

   [SR-Traffic-Accounting]
              Ali, Z., Filsfils, C., Talaulikar, K., Sivabalan, S.,
              Horneffer, M., Raszuk, R., Litkowski, S., Voyer, D.,
              Morton, R., and G. Dawra, "Traffic Accounting in Segment
              Routing Networks", Work in Progress, Internet-Draft,
              draft-ali-spring-sr-traffic-accounting-06, 13 November
              2021, <https://datatracker.ietf.org/doc/html/draft-ali-
              spring-sr-traffic-accounting-06>.

Acknowledgements

   I would like to thank the IE doctors, Paul Aitken and Andrew Feren,
   as well Benoit as Benoît Claise, Loa Andersson, Tianran Zhou, Pierre Francois,
   François, Bruno Decreane, Decraene, Paolo Lucente, Hannes Gredler, Ketan
   Talaulikar, Sabrina Tanamal, Erik Auerswald, Sergey Fomin, Mohamed
   Boucadair, Tom Petch, Qin Wu Wu, and Matthias Arnold for their review
   and valuable comments.  Many thanks also to Robert Wilton for the AD
   review.  Thanks to Alvaro Retana, Eric Vyncke Éric Vyncke, and Benjamin Kaduk for
   the IESG review.

Author's Address

   Thomas Graf
   Swisscom
   Binzring 17
   CH-8045 Zurich Zürich
   Switzerland

   Email: thomas.graf@swisscom.com