BGP-LS Advertisement of SR Policy Performance Metric
draft-lin-idr-bgpls-te-policy-pm-08
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| Document | Type | Active Internet-Draft (idr WG) | |
|---|---|---|---|
| Authors | Changwang Lin , Yisong Liu , Yongqing Zhu , Ran Chen | ||
| Last updated | 2026-02-09 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
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| Additional resources | Mailing list discussion | ||
| Stream | WG state | Candidate for WG Adoption | |
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| Send notices to | (None) |
draft-lin-idr-bgpls-te-policy-pm-08
Network Working Group C. Lin
Internet Draft New H3C Technologies
Intended status: Standards Track Y. Liu
Expires: August 13, 2026 China Mobile
Y. Zhu
China Telecom
R. Chen
ZTE Corporation
February 09, 2026
BGP-LS Advertisement of SR Policy Performance Metric
draft-lin-idr-bgpls-te-policy-pm-08
Abstract
This document describes a way to advertise the performance metrics
for Traffic Engineering (TE) Policy using BGP Link State (BGP-LS).
Status of this Memo
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This Internet-Draft will expire on August 13, 2026.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction...................................................2
1.1. Requirements Language.....................................3
2. Advertisement of SR Policy Performance Metric..................3
3. Extensions for Round-trip TE Performance Metric................4
3.1. Round-trip Delay TLV......................................4
3.2. Min/Max Round-trip Delay TLV..............................4
3.3. Round-trip Delay Variation TLV............................5
3.4. Round-trip Loss TLV.......................................6
4. Security Considerations........................................7
5. Management Considerations......................................7
6. IANA Considerations............................................7
7. References.....................................................8
7.1. Normative References......................................8
7.2. Informative References....................................9
Authors' Addresses...............................................10
1. Introduction
BGP Link State (BGP-LS) can be used to distribute link-state and
traffic engineering (TE) information to external components
[RFC9552]. [RFC9857] describes the mechanism for BGP-LS to
distribute the information of TE policies.
In some network scenarios, the controller needs to obtain the
performance information of TE Policies, which can be used in service
placement to meet better customer requirements and utilize network
resources more efficiently.
[I-D.ietf-spring-stamp-srpm-mpls] and [I-D.ietf-spring-stamp-srpm-
srv6] describe the procedures for Performance Measurement in SR
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networks, using STAMP as defined in [RFC8762]. The described
procedure is used for SR paths [RFC8402] (including SR Policies
[RFC9256]).
This document describes a way to advertise the performance metrics
for Traffic Engineering (TE) Policy using BGP Link State (BGP-LS).
1.1. Requirements Language
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.
2. Advertisement of SR Policy Performance Metric
[RFC8571] defines several Link Attribute TLVs for BGP-LS to carry
the IGP Traffic Engineering Performance Metric Extensions:
TLV Code Point Value
--------------------------------------------------------
1114 Unidirectional Link Delay
1115 Min/Max Unidirectional Link Delay
1116 Unidirectional Delay Variation
1117 Unidirectional Link Loss
The above TLVs can be reused to report performance metrics for TE
Policies. They enable reporting for either a specific SID-List or a
particular SR candidate path. Therefore, these TLVs may serve as
sub-TLVs of the SR Segment List TLV, or alternatively provide
performance metrics for the SR Policy at the candidate path level.
When used to describe the performance metric of the SR Policy NLRI,
they are carried in the optional non-transitive BGP Path Attribute
"BGP-LS Attribute" defined in [RFC9552]. The semantics of the above
TLVs comply with [RFC8571], except for that they are extended to
describe TE Policies besides IGP links.
The performance metric of SR Policy may be measured at the headend,
for example, by using STAMP for SR Policy [I-D.ietf-spring-stamp-
srpm-mpls] and [I-D.ietf-spring-stamp-srpm-srv6]. But the
measurement methods are out of the scope of this document.
The existing performance metrics above are all unidirectional.
However, there are also requirements to advertise round-trip
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performance metrics for TE Policies. The BGP-LS extensions for
round-trip TE performance metrics are defined in the following
section.
3. Extensions for Round-trip TE Performance Metric
3.1. Round-trip Delay TLV
This TLV advertises the average round-trip delay for SR Policy. It
can report round-trip delay for either a specific SID-List or a
particular SR candidate path. As such, this TLV may function either
as a sub-TLV of the SR Segment List TLV or provide round-trip delay
for the SR Policy at the candidate path level.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
o Type: TBD
o Length: 4
o Reserved: Reserved for future use. MUST be set to 0 when sent and
MUST be ignored when received.
o A: Anomalous (A) Bit. Same with the A Bit in Unidirectional Link
Delay TLV [RFC8571].
o Delay: Similar with the Delay filed in Unidirectional Link Delay
TLV [RFC8571], except for that the delay is round-trip.
3.2. Min/Max Round-trip Delay TLV
This TLV advertises the minimum and maximum round-trip delay for SR
Policy. It can report minimum and maximum round-trip delay for
either a specific SID-List or a particular SR candidate path. As
such, this TLV may function either as a sub-TLV of the SR Segment
List TLV or provide minimum and maximum round-trip delay for the SR
Policy at the candidate path level.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Min Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Max Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
o Type: TBD
o Length: 4
o Reserved: Reserved for future use. MUST be set to 0 when sent and
MUST be ignored when received.
o A: Anomalous (A) Bit. Same with the A Bit in Min/Max
Unidirectional Link Delay TLV [RFC8571].
o Min Delay: Similar with the Min Delay filed in Min/Max
Unidirectional Link Delay TLV [RFC8571], except for that the
delay is round-trip.
o Max Delay: Similar with the Max Delay filed in Min/Max
Unidirectional Link Delay TLV [RFC8571], except for that the
delay is round-trip.
3.3. Round-trip Delay Variation TLV
This TLV advertises the average round-trip delay variation for SR
Policy. It can report average round-trip delay variation for either
a specific SID-List or a particular SR candidate path. As such, this
TLV may function either as a sub-TLV of the SR Segment List TLV or
provide average round-trip delay variation for the SR Policy at the
candidate path level.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Delay Variation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
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o Type: TBD
o Length: 4
o Reserved: Reserved for future use. MUST be set to 0 when sent and
MUST be ignored when received.
o A: Anomalous (A) Bit. Same with the A Bit in Unidirectional Delay
Variation TLV [RFC8571].
o Delay Variation: Similar with the Delay Variation filed in
Unidirectional Delay Variation TLV [RFC8571], except for that the
delay variation is round-trip.
3.4. Round-trip Loss TLV
This TLV advertises the round-trip loss for SR Policy. It can report
round-trip loss for either a specific SID-List or a particular SR
candidate path. As such, this TLV may function either as a sub-TLV
of the SR Segment List TLV or provide round-trip loss for the SR
Policy at the candidate path level.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Loss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
o Type: TBD
o Length: 4
o Reserved: Reserved for future use. MUST be set to 0 when sent and
MUST be ignored when received.
o A: Anomalous (A) Bit. Same with the A Bit in Unidirectional Link
Loss TLV [RFC8571].
o Loss: Similar with the Link Loss filed in Unidirectional Link
Loss TLV [RFC8571], except for that the loss is round-trip.
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4. Security Considerations
The procedures and protocol extensions defined in this document do
not affect the BGP security model.
The sub-TLVs introduced in this document allow an operator to
advertise state information of SR Policy (e.g., bandwidth, delay),
which may be sensitive and dynamic in nature.
In very large networks, instability could occur if measurement
intervals are configured at a frequency that overwhelms the
processing capacity for announcement intervals. Therefore, care must
be taken when configuring these values. Implementations SHOULD NOT
allow the inter-update timer to be set lower than the measurement
interval. Additionally, implementations SHOULD enforce configurable
constraints to mitigate the risk of instability.
For a discussion of BGP security, refer to the "Security
Considerations" section of [RFC4271]. Analyses of BGP security
issues are also provided in [RFC4272] and [RFC6952]. Security
considerations related to the acquisition and distribution of BGP-LS
information are discussed in [RFC9552], [RFC9830], and [RFC9857].
The mechanism proposed in this document is subject to the same
vulnerabilities as any other protocol that relies on BGP-LS.
5. Management Considerations
An implementation SHOULD allow the operator to specify neighbors to
which Link-State NLRIs will be advertised and from which Link-State
NLRIs will be accepted.
An implementation SHOULD allow the operator to control the content
of advertisements, such as whether or not to advertise latency,
packet loss rate, bidirectional latency, and bidirectional packet
loss rate.
An implementation SHOULD allow the operator to control advertisement
thresholds to avoid frequent announcements.
6. IANA Considerations
This document defines the following TLVs for BGP-LS.
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TLV Code Point Value
--------------------------------------------------------
TBD Round-trip Delay
TBD Min/Max Round-trip Delay
TBD Round-trip Variation
TBD Round-trip Loss
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI
10.17487/RFC4271, January 2006,<https://www.rfc-
editor.org/info/rfc4271>.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<https://www.rfc-editor.org/info/rfc6952>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, May 2017
[RFC8571] Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and
C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of
IGP Traffic Engineering Performance Metric Extensions",
RFC 8571, DOI 10.17487/RFC8571, March 2019,
<https://www.rfc-editor.org/info/rfc8571>.
[RFC9830] Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., and
Jain, D., "Advertising Segment Routing Policies in BGP",
RFC 9857, DOI 10.17487/RFC9830, September 2025,
[RFC9552] Talaulikar, K., Ed., "Distribution of Link-State and
Traffic Engineering Information Using BGP", RFC 9552, DOI
10.17487/RFC9552, December 2023, <https://www.rfc-
editor.org/info/rfc9552>.
[RFC9857] Previdi, S., Talaulikar, K., Dong, J., Gredler, H., and
Tantsura, J., "Advertisement of Segment Routing Policies
using BGP Link-State", RFC 9857, DOI 10.17487/RFC9857,
October 2025, <https://www.rfc-editor.org/info/rfc9857>.
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7.2. Informative References
[I-D.ietf-spring-stamp-srpm-mpls] Gandhi, R., Filsfils, C., Voyer,
D., Chen, M., and R. F.Foote, "Performance Measurement
Using Simple Two-Way Active Measurement Protocol (STAMP)
for Segment Routing over the MPLS Data Plane", Work in
Progress, Internet-Draft, draft-ietf-spring-stamp-srpm-
mpls-00, 02 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
stamp-srpm-mpls-00>.
[I-D.ietf-spring-stamp-srpm-srv6] Gandhi, R., Filsfils, C., Voyer,
D., Chen, M., and R. F.Foote, "Performance Measurement
Using Simple Two-Way Active Measurement Protocol (STAMP)
for Segment Routing over the SRv6 Data Plane ", Work in
Progress, Internet-Draft, draft-ietf-spring-stamp-srpm-
srv6-00, 02 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring-
stamp-srpm-srv6-00>.
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Authors' Addresses
Changwang Lin
New H3C Technologies
Email: linchangwang.04414@h3c.com
Yisong Liu
China Mobile
Email: liuyisong@chinamobile.com
Yongqing Zhu
China Telecom
Guangzhou
Email: zhuyq8@chinatelecom.cn
Ran Chen
ZTE Corporation
China
Email: chen.ran@zte.com.cn
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