Network Working Group                                            T. Graf
Internet-Draft                                                  Swisscom
Intended status: Standards Track                           June 24, 2021
Expires: December 26, 2021


        Export of MPLS Segment Routing Label Type Information in
                   IP Flow Information Export (IPFIX)
             draft-ietf-opsawg-ipfix-mpls-sr-label-type-04

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 within a Segment Routing domain.  In
   particular, this document defines four code points for the IPFIX
   mplsTopLabelType Information Element for IS-IS, OSPFv2, OSPFv3, and
   BGP MPLS Segment Routing extensions.

Status of This Memo

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   This Internet-Draft will expire on December 26, 2021.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

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

1.  Introduction

   Four new routing protocol extensions, OSPFv2 Extensions [RFC8665],
   OSPFv3 Extensions [RFC8666], IS-IS Extensions [RFC8667] and BGP
   Prefix Segment Identifiers (Prefix-SIDs) [RFC8669] have been defined
   as routing protocols that are able to propagate Segment Routing (SR)
   labels for the MPLS data plane [RFC8660].

   Also [I-D.ali-spring-sr-traffic-accounting] describes how IP Flow
   Information Export [RFC7012] can be leveraged to account 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.  Section 7.2 of [RFC7012]
   creates the "IPFIX MPLS label type (Value 46)" subregistry
   [IANA-IPFIX] where MPLS label type 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 four new code points to the IPFIX IE
   mplsTopLabelType(46) for IS-IS, OSPFv2, OSPFv3 and BGP Prefix-SID, 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 in the context of




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   Seamless MPLS SR described in Section 4.6 of
   [I-D.hegde-spring-mpls-seamless-sr].

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

   o  how many packets are forwarded or dropped

   o  if dropped, for which reasons, and

   o  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 because they may share the
   same label allocation range.  This is, for example, the case for IGP-
   Adjacency SIDs, LDP and dynamic BGP labels.

3.  IANA Considerations

   This document requests IANA to allocate the following code points in
   the existing subregistry "IPFIX MPLS label type (Value 46)" under the
   "IPFIX Information Elements" registry available at [IANA-IPFIX].


      +------+--------------------------------+----------+-------------+
      | Value|       Description              | Reference|  Requester  |
      +------+--------------------------------+----------+-------------+
      | TBD1 | OSPFv2 Segment Routing         |  RFC8665 | [RFC-to-be] |
      +------+--------------------------------+----------+-------------+
      | TBD2 | OSPFv3 Segment Routing         |  RFC8666 | [RFC-to-be] |
      +------+--------------------------------+----------+-------------+
      | TBD3 | IS-IS Segment Routing          |  RFC8667 | [RFC-to-be] |
      +------+--------------------------------+----------+-------------+
      | TBD4 | BGP Segment Routing Prefix-SID |  RFC8669 | [RFC-to-be] |
      +------+--------------------------------+----------+-------------+

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

   Note to the RFC-Editor:

   o  Please replace TBD1 - TBD4 with the values allocated by IANA

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






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4.  Operational Considerations

   In the IE mplsTopLabelType(46), the BGP code point 4 refers to the
   label value in MP_REACH_NLRI path attribute described in Section 2 of
   [RFC8277], while the BGP Segment Routing Prefix-SID code point TBD4
   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 no extra security considerations regarding the
   allocation of these new IPFIX IEs compared to [RFC7012].

6.  Acknowledgements

   I would like to thank to the IE doctors, Paul Aitken and Andrew
   Feren, as well Benoit Claise, Loa Andersson, Tianran Zhou, Pierre
   Francois, Bruno Decreane, Paolo Lucente, Hannes Gredler, Ketan
   Talaulikar, Sabrina Tanamal, Erik Auerswald, Sergey Fomin, Mohamed
   Boucadair, Tom Petch and Qin Wu for their review and valuable
   comments.

7.  References

7.1.  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.  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", draft-
              ali-spring-sr-traffic-accounting-05 (work in progress),
              April 2021.

   [I-D.hegde-spring-mpls-seamless-sr]
              Hegde, S., Bowers, C., Xu, X., Gulko, A., Bogdanov, A.,
              Uttaro, J., Jalil, L., Khaddam, M., Alston, A., and L. M.
              Contreras, "Seamless SR Problem Statement", draft-hegde-
              spring-mpls-seamless-sr-05 (work in progress), February
              2021.




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

   [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>.

   [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>.

Author's Address








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   Thomas Graf
   Swisscom
   Binzring 17
   Zurich  8045
   Switzerland

   Email: thomas.graf@swisscom.com












































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