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

Network Working Group                                            T. Graf
Internet-Draft                                                  Swisscom
Intended status: Informational                         18 September 2021
Expires: 22 March 2022

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

Status of This Memo

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Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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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.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Four routing protocol extensions, OSPFv2 Extensions [RFC8665], OSPFv3
   Extensions [RFC8666], IS-IS Extensions [RFC8667], 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] describes how IP Flow
   Information Export [RFC7012] can be leveraged in dimensional data
   modelling 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.

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2.  MPLS Segment Routing Top Label Type

   By introducing five new code points to the IPFIX IE
   mplsTopLabelType(46) for PCE, 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 [RFC8669].  For
   example, the motivation and benefits for such a migration in large-
   scale data centers are described in [RFC8670].

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

   *  how many packets are forwarded or dropped

   *  if 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 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 [RFC7012] available at
   [IANA-IPFIX].

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      +-------+--------------------------------+----------------------+
      | Value |          Description           |      Reference       |
      +-------+--------------------------------+----------------------+
      | TBD1  | Path Computation Element       | [RFC-to-be], RFC8664 |
      +-------+--------------------------------+----------------------+
      | TBD2  | OSPFv2 Segment Routing         | [RFC-to-be], RFC8665 |
      +-------+--------------------------------+----------------------+
      | TBD3  | OSPFv3 Segment Routing         | [RFC-to-be], RFC8666 |
      +-------+--------------------------------+----------------------+
      | TBD4  | IS-IS Segment Routing          | [RFC-to-be], RFC8667 |
      +-------+--------------------------------+----------------------+
      | TBD5  | BGP Segment Routing Prefix-SID | [RFC-to-be], RFC8669 |
      +-------+--------------------------------+----------------------+

      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 to
      this document

   Note IANA:

   *  Suggest to move the existing RFC references in the additional
      information column of IE mplsTopLabelType(46) to reference column
      for codepoint 3, 4 and 5.

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 TBD5
   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 significant extra security considerations regarding
   the allocation of these new IPFIX IEs compared to [RFC7012].

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6.  Acknowledgements

   I would like to thank 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, Qin 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 and Benjamin Kaduk for the IESG
   review.

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", 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 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>.

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   [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>.

Author's Address

   Thomas Graf
   Swisscom
   Binzring 17
   CH-8045 Zurich
   Switzerland

   Email: thomas.graf@swisscom.com

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