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.
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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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