Export of MPLS Segment Routing Label Type Information in
IP Flow Information Export (IPFIX)SwisscomBinzring 17Zurich8045Switzerlandthomas.graf@swisscom.comThis 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 four code points for the IPFIX
mplsTopLabelType Information Element for IS-IS, OSPFv2, OSPFv3, and BGP
MPLS Segment Routing extensions.Four new routing protocol extensions, OSPFv2
Extensions, OSPFv3 Extensions,
IS-IS Extensions and BGP Prefix Segment Identifiers (Prefix-SIDs)
have been defined as routing protocols that are able to propagate
Segment Routing (SR) labels for the MPLS data plane .Also, describes
how IP Flow Information Export can be leveraged
to account traffic to MPLS SR label dimensions within a Segment Routing
domain.In , 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
creates the "IPFIX
MPLS label type (Value 46)" subregistry where MPLS label type
should be added. This document defines new code points to address
typical use cases that are discussed in Section 2.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 .Another use case is to monitor MPLS control plane migrations from
dynamic BGP labels to BGP Prefix-SIDs in the
context of Seamless MPLS SR described in Section 4.6 of .Both use cases can be verified by using mplsTopLabelType(46),
mplsTopLabelIPv4Address(47), mplsTopLabelIPv6Address(140),
mplsTopLabelStackSection(70) and forwardingStatus(89) IEs to inferhow many packets are forwarded or droppedif dropped, for which reasons, andthe MPLS provider edge loopback address and label protocolBy 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.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 .Note to the RFC-Editor:Please replace TBD1 - TBD4 with the values allocated by IANAPlease replace the [RFC-to-be] with the RFC number assigned to
this documentIn 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
, 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 . These values are
thus used for those distinct purposes.There exists no extra security considerations regarding the
allocation of these new IPFIX IEs compared to .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.IANA, IPFIX MPLS label type (Value 46)