Internet DRAFT - draft-xzc-lsr-mpls-flc-flrd
draft-xzc-lsr-mpls-flc-flrd
LSR Working Group X. Min
Internet-Draft Z. Zhang
Intended status: Standards Track ZTE Corp.
Expires: 19 February 2022 W. Cheng
China Mobile
18 August 2021
Signaling Flow-ID Label Capability and Flow-ID Readable Label Depth
Using IGP and BGP-LS
draft-xzc-lsr-mpls-flc-flrd-01
Abstract
Flow-ID Label (FL) is used for MPLS flow identification and flow-
based performance measurement with alternate marking method. The
ability to process Flow-ID labels is called Flow-ID Label Capability
(FLC), and the capability of reading the maximum label stack depth
and performing FL-based performance measurement is called Flow-ID
Readable Label Depth (FRLD). This document defines a mechanism to
signal the FLC and the FRLD using IGP and BGP-LS.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 19 February 2022.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. Advertising FLC Using IGP . . . . . . . . . . . . . . . . . . 3
2.1. Advertising FLC Using IS-IS . . . . . . . . . . . . . . . 3
2.2. Advertising FLC Using OSPFv2 . . . . . . . . . . . . . . 3
2.3. Advertising FLC Using OSPFv3 . . . . . . . . . . . . . . 4
3. Advertising FRLD Using IGP . . . . . . . . . . . . . . . . . 4
4. Signaling FLC and FRLD in BGP-LS . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
As specified in [I-D.ietf-mpls-inband-pm-encapsulation], Flow-ID
Label (FL) is used for MPLS flow identification and flow-based
performance measurement with alternate marking method.
Flow-ID Label may appear multiple times in a label stack with
variable depth, so both the Flow-ID Label Capability (FLC) and the
Flow-ID Readable Label Depth (FRLD) are defined in
[I-D.ietf-mpls-inband-pm-encapsulation].
Analogous to [RFC9088] and [RFC9089], this document defines a
mechanism to signal the FLC and the FRLD using IGP and BGP-LS,
specifically, IGP includes IS-IS, OSPFv2 and OSPFv3.
1.1. Terminology
This memo makes use of the terms defined in
[I-D.ietf-mpls-inband-pm-encapsulation] and [RFC8491].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. Advertising FLC Using IGP
Even though FLC is a property of the node, in some cases it is
advantageous to associate and advertise the FLC with a prefix, so FLC
is advertised with a prefix in this document.
If a router has multiple interfaces, the router MUST NOT announce FLC
unless all of its interfaces are capable of processing FLs.
If the router supports FLs on all of its interfaces, it SHOULD
advertise the FLC with every local host prefix it advertises in IGP.
2.1. Advertising FLC Using IS-IS
Next to the ELC Flag (E-flag) defined in Section 3 of [RFC9088], a
new bit FLC Flag (F-flag) is defined, which is Bit 4 in the Prefix
Attribute Flags [RFC7794], as shown in Figure 1.
0 1 2 3 4 5 6 7...
+-+-+-+-+-+-+-+-+...
|X|R|N|E|F| ...
+-+-+-+-+-+-+-+-+...
Figure 1: Prefix Attribute Flags
F-Flag: FLC Flag (Bit 4)
Set for local host prefix of the originating node if it supports
FLC on all interfaces.
The FLC signaling MUST be preserved when a router propagates a prefix
between ISIS levels [RFC5302].
2.2. Advertising FLC Using OSPFv2
Next to the ELC Flag (E-flag) defined in Section 3.1 of [RFC9089], a
new bit FLC Flag (F-flag) is defined, which is Bit 3 in Flags field
of OSPFv2 Extended Prefix TLV [RFC7684]:
0x10 - F-Flag (FLC Flag): Set for local host prefix of the
originating node if it supports FLC on all interfaces.
The FLC signaling MUST be preserved when an OSPFv2 Area Border Router
(ABR) distributes information between areas. To do so, an ABR MUST
originate an OSPFv2 Extended Prefix Opaque LSA [RFC7684] including
the received FLC setting.
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2.3. Advertising FLC Using OSPFv3
Next to the ELC Flag (E-flag) defined in Section 3.2 of [RFC9089], a
new bit FLC Flag (F-flag) is defined, which is Bit 0 in OSPFv3
PrefixOptions field [RFC5340]:
0x80 - F-Flag (FLC Flag): Set for local host prefix of the
originating node if it supports FLC on all interfaces.
The FLC signaling MUST be preserved when an OSPFv3 Area Border Router
(ABR) distributes information between areas. The setting of the FLC
Flag in the Inter-Area-Prefix-LSA [RFC5340] or in the Inter-Area-
Prefix TLV [RFC8362], generated by an ABR, MUST be the same as the
value the FLC Flag associated with the prefix in the source area.
3. Advertising FRLD Using IGP
As requested by [RFC8491], IANA has created an IANA-managed registry
titled "IGP MSD-Types" to identify MSD-Types. A new MSD-Type, called
FRLD-MSD, is defined to advertise the FRLD of a given router. The
MSD-Type code 3 is requested to be assigned by IANA for FRLD-MSD.
The MSD-Value field is set to the FRLD in the range between 0 to 255.
If a router has multiple interfaces with different capabilities of
reading the maximum label stack depth, the router MUST advertise the
smallest value found across all of its interfaces.
For IS-IS, the FRLD is advertised in a Node MSD Sub-TLV [RFC8491]
using the FRLD-MSD type.
For OSPF including both OSPFv2 and OSPFv3, the FRLD is advertised in
a Node MSD TLV [RFC8476] using the FRLD-MSD type.
The absence of FRLD-MSD advertisements indicates only that the
advertising node does not support advertisement of this capability.
4. Signaling FLC and FRLD in BGP-LS
The IGP extensions defined in this document can be advertised via
BGP-LS (Distribution of Link-State and TE Information Using BGP)
[RFC7752] using existing BGP-LS TLVs.
The FLC is advertised using the Prefix Attribute Flags TLV as defined
in [RFC9085].
The FRLD-MSD is advertised using the Node MSD TLV as defined in
[RFC8814].
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5. Security Considerations
This document does not raise any additional security issues beyond
those of the specifications referred to in the list of normative
references.
6. IANA Considerations
This document requests the following allocations from IANA:
- Bit 4 in the Bit Values for Prefix Attribute Flags Sub-TLV
registry is requested to be assigned to the FLC Flag (F-Flag).
- Flag 0x10 in the OSPFv2 Extended Prefix TLV Flags registry is
requested to be assigned to the FLC Flag (F-Flag).
- Bit 0x80 in the "OSPFv3 Prefix Options (8 bits)" registry is
requested to be assigned to the FLC Flag (F-Flag).
- Type 3 in the IGP MSD-Types registry is requested to be assigned
to the FRLD-MSD.
7. Acknowledgements
TBA.
8. Normative References
[I-D.ietf-mpls-inband-pm-encapsulation]
Cheng, W., Min, X., Zhou, T., Dong, X., and Y. Peleg,
"Encapsulation For MPLS Performance Measurement with
Alternate Marking Method", Work in Progress, Internet-
Draft, draft-ietf-mpls-inband-pm-encapsulation-01, 11
April 2021, <https://www.ietf.org/archive/id/draft-ietf-
mpls-inband-pm-encapsulation-01.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5302] Li, T., Smit, H., and T. Przygienda, "Domain-Wide Prefix
Distribution with Two-Level IS-IS", RFC 5302,
DOI 10.17487/RFC5302, October 2008,
<https://www.rfc-editor.org/info/rfc5302>.
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[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and
U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4
and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794,
March 2016, <https://www.rfc-editor.org/info/rfc7794>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and
F. Baker, "OSPFv3 Link State Advertisement (LSA)
Extensibility", RFC 8362, DOI 10.17487/RFC8362, April
2018, <https://www.rfc-editor.org/info/rfc8362>.
[RFC8476] Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,
"Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476,
DOI 10.17487/RFC8476, December 2018,
<https://www.rfc-editor.org/info/rfc8476>.
[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
DOI 10.17487/RFC8491, November 2018,
<https://www.rfc-editor.org/info/rfc8491>.
[RFC8814] Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G.,
and N. Triantafillis, "Signaling Maximum SID Depth (MSD)
Using the Border Gateway Protocol - Link State", RFC 8814,
DOI 10.17487/RFC8814, August 2020,
<https://www.rfc-editor.org/info/rfc8814>.
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[RFC9085] Previdi, S., Talaulikar, K., Ed., Filsfils, C., Gredler,
H., and M. Chen, "Border Gateway Protocol - Link State
(BGP-LS) Extensions for Segment Routing", RFC 9085,
DOI 10.17487/RFC9085, August 2021,
<https://www.rfc-editor.org/info/rfc9085>.
[RFC9088] Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,
and M. Bocci, "Signaling Entropy Label Capability and
Entropy Readable Label Depth Using IS-IS", RFC 9088,
DOI 10.17487/RFC9088, August 2021,
<https://www.rfc-editor.org/info/rfc9088>.
[RFC9089] Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S.,
and M. Bocci, "Signaling Entropy Label Capability and
Entropy Readable Label Depth Using OSPF", RFC 9089,
DOI 10.17487/RFC9089, August 2021,
<https://www.rfc-editor.org/info/rfc9089>.
Authors' Addresses
Xiao Min
ZTE Corp.
Nanjing
China
Email: xiao.min2@zte.com.cn
Zheng(Sandy) Zhang
ZTE Corp.
Nanjing
China
Email: zhang.zheng@zte.com.cn
Weiqiang Cheng
China Mobile
Beijing
China
Email: chengweiqiang@chinamobile.com
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