draft-ietf-idr-sr-policy-safi-09.txt   draft-ietf-idr-sr-policy-safi-10.txt 
Network Working Group S. Previdi Network Working Group S. Previdi
Internet-Draft Huawei Technologies Internet-Draft Huawei Technologies
Updates: 9012 (if approved) C. Filsfils Updates: 9012 (if approved) C. Filsfils
Intended status: Standards Track K. Talaulikar, Ed. Intended status: Standards Track K. Talaulikar, Ed.
Expires: 6 April 2025 Cisco Systems Expires: 7 May 2025 Cisco Systems
P. Mattes P. Mattes
Microsoft Microsoft
D. Jain D. Jain
Google Google
3 October 2024 3 November 2024
Advertising Segment Routing Policies in BGP Advertising Segment Routing Policies in BGP
draft-ietf-idr-sr-policy-safi-09 draft-ietf-idr-sr-policy-safi-10
Abstract Abstract
A Segment Routing (SR) Policy is an ordered list of segments (i.e., A Segment Routing (SR) Policy is an ordered list of segments (i.e.,
instructions) that represent a source-routed policy. An SR Policy instructions) that represent a source-routed policy. An SR Policy
consists of one or more candidate paths, each consisting of one or consists of one or more candidate paths, each consisting of one or
more segment lists. A headend may be provisioned with candidate more segment lists. A headend may be provisioned with candidate
paths for an SR Policy via several different mechanisms, e.g., CLI, paths for an SR Policy via several different mechanisms, e.g., CLI,
NETCONF, PCEP, or BGP. NETCONF, PCEP, or BGP.
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This Internet-Draft will expire on 6 April 2025. This Internet-Draft will expire on 7 May 2025.
Copyright Notice Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 10 Sub-TLVs . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4. SR Policy Sub-TLVs . . . . . . . . . . . . . . . . . . . 10 2.4. SR Policy Sub-TLVs . . . . . . . . . . . . . . . . . . . 10
2.4.1. Preference Sub-TLV . . . . . . . . . . . . . . . . . 11 2.4.1. Preference Sub-TLV . . . . . . . . . . . . . . . . . 11
2.4.2. Binding SID Sub-TLV . . . . . . . . . . . . . . . . . 11 2.4.2. Binding SID Sub-TLV . . . . . . . . . . . . . . . . . 11
2.4.3. SRv6 Binding SID Sub-TLV . . . . . . . . . . . . . . 13 2.4.3. SRv6 Binding SID Sub-TLV . . . . . . . . . . . . . . 13
2.4.4. Segment List Sub-TLV . . . . . . . . . . . . . . . . 15 2.4.4. Segment List Sub-TLV . . . . . . . . . . . . . . . . 15
2.4.5. Explicit NULL Label Policy Sub-TLV . . . . . . . . . 21 2.4.5. Explicit NULL Label Policy Sub-TLV . . . . . . . . . 21
2.4.6. Policy Priority Sub-TLV . . . . . . . . . . . . . . . 23 2.4.6. Policy Priority Sub-TLV . . . . . . . . . . . . . . . 23
2.4.7. Policy Candidate Path Name Sub-TLV . . . . . . . . . 23 2.4.7. Policy Candidate Path Name Sub-TLV . . . . . . . . . 23
2.4.8. Policy Name Sub-TLV . . . . . . . . . . . . . . . . . 24 2.4.8. Policy Name Sub-TLV . . . . . . . . . . . . . . . . . 24
3. Color Extended Community . . . . . . . . . . . . . . . . . . 25 3. Color Extended Community . . . . . . . . . . . . . . . . . . 26
4. SR Policy Operations . . . . . . . . . . . . . . . . . . . . 27 4. SR Policy Operations . . . . . . . . . . . . . . . . . . . . 27
4.1. Advertisement of SR Policies . . . . . . . . . . . . . . 27 4.1. Advertisement of SR Policies . . . . . . . . . . . . . . 27
4.2. Reception of an SR Policy NLRI . . . . . . . . . . . . . 27 4.2. Reception of an SR Policy NLRI . . . . . . . . . . . . . 27
4.2.1. Validation of an SR Policy NLRI . . . . . . . . . . . 28 4.2.1. Validation of an SR Policy NLRI . . . . . . . . . . . 28
4.2.2. Eligibility for Local Use of an SR Policy NLRI . . . 28 4.2.2. Eligibility for Local Use of an SR Policy NLRI . . . 28
4.2.3. Propagation of an SR Policy . . . . . . . . . . . . . 29 4.2.3. Propagation of an SR Policy . . . . . . . . . . . . . 29
5. Error Handling and Fault Management . . . . . . . . . . . . . 29 5. Error Handling and Fault Management . . . . . . . . . . . . . 29
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
6.1. Subsequent Address Family Identifiers (SAFI) 6.1. Subsequent Address Family Identifiers (SAFI)
Parameters . . . . . . . . . . . . . . . . . . . . . . . 31 Parameters . . . . . . . . . . . . . . . . . . . . . . . 31
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- B-Flag: This flag, when set, indicates the presence of the SRv6 - B-Flag: This flag, when set, indicates the presence of the SRv6
Endpoint Behavior and SID Structure encoding specified in Endpoint Behavior and SID Structure encoding specified in
Section 2.4.4.2.4. Section 2.4.4.2.4.
- The unassigned bits in the Flag octet MUST be set to zero upon - The unassigned bits in the Flag octet MUST be set to zero upon
transmission and MUST be ignored upon receipt. transmission and MUST be ignored upon receipt.
* RESERVED: 1 octet of reserved bits. This field MUST be set to * RESERVED: 1 octet of reserved bits. This field MUST be set to
zero on transmission and MUST be ignored on receipt. zero on transmission and MUST be ignored on receipt.
* SRv6 Binding SID: Contains a 16-octet SRv6 SID. * SRv6 Binding SID: Contains a 16-octet SRv6 SID. The value 0 MAY
be used when the controller wants to indicate the desired SRv6
Endpoint Behavior, SID Structure, or flags without specifying the
BSID.
* SRv6 Endpoint Behavior and SID Structure: Optional, as defined in * SRv6 Endpoint Behavior and SID Structure: Optional, as defined in
Section 2.4.4.2.4. Section 2.4.4.2.4. The SRv6 Endpoint Behavior and SID Structure
MUST NOT be included when the SRv6 SID has not been included.
2.4.4. Segment List Sub-TLV 2.4.4. Segment List Sub-TLV
The Segment List sub-TLV encodes a single explicit path towards the The Segment List sub-TLV encodes a single explicit path towards the
endpoint as described in section 5.1 of [RFC9256]. The Segment List endpoint as described in section 5.1 of [RFC9256]. The Segment List
sub-TLV includes the elements of the paths (i.e., segments) as well sub-TLV includes the elements of the paths (i.e., segments) as well
as an optional Weight sub-TLV. as an optional Weight sub-TLV.
The Segment List sub-TLV may exceed 255 bytes in length due to a The Segment List sub-TLV may exceed 255 bytes in length due to a
large number of segments. A 2-octet length is thus required. large number of segments. A 2-octet length is thus required.
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present else it MUST be 18. present else it MUST be 18.
* Flags: 1 octet of flags as defined in Section 2.4.4.2.3. * Flags: 1 octet of flags as defined in Section 2.4.4.2.3.
* RESERVED: 1 octet of reserved bits. This field MUST be set to * RESERVED: 1 octet of reserved bits. This field MUST be set to
zero on transmission and MUST be ignored on receipt. zero on transmission and MUST be ignored on receipt.
* SRv6 SID: 16 octets of IPv6 address. * SRv6 SID: 16 octets of IPv6 address.
* SRv6 Endpoint Behavior and SID Structure: Optional, as defined in * SRv6 Endpoint Behavior and SID Structure: Optional, as defined in
Section 2.4.4.2.4. Section 2.4.4.2.4. The SRv6 Endpoint Behavior and SID Structure
MUST NOT be included when the SRv6 SID has not been included.
The Sub-TLV code point 2 defined for the advertisement of Segment The Sub-TLV code point 2 defined for the advertisement of Segment
Type B in the earlier versions of this document has been deprecated Type B in the earlier versions of this document has been deprecated
to avoid backward compatibility issues. to avoid backward compatibility issues.
2.4.4.2.3. Segment Flags 2.4.4.2.3. SR Policy Segment Flags
The Segment Types sub-TLVs described above may contain the following The Segment Types sub-TLVs described above may contain the following
flags in the "Flags" field defined in Section 6.8: SR Policy Segment Flags in their "Flags" field. Also refer to
Section 6.8:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|V| |B| | |V| |B| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 22: Segment Flags Figure 22: SR Policy Segment Flags
where: where:
V-Flag: This flag, when set, is used by SRPM for "SID V-Flag: This flag, when set, is used by SRPM for "SID
verification" as described in Section 5.1 of [RFC9256]. verification" as described in Section 5.1 of [RFC9256].
B-Flag: This flag, when set, indicates the presence of the SRv6 B-Flag: This flag, when set, indicates the presence of the SRv6
Endpoint Behavior and SID Structure encoding specified in Endpoint Behavior and SID Structure encoding specified in
Section 2.4.4.2.4. Section 2.4.4.2.4.
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via BGP SR Policy SAFI along with their operational states. via BGP SR Policy SAFI along with their operational states.
9. Acknowledgments 9. Acknowledgments
The authors of this document would like to thank Shyam Sethuram, John The authors of this document would like to thank Shyam Sethuram, John
Scudder, Przemyslaw Krol, Alex Bogdanov, Nandan Saha, Bruno Decraene, Scudder, Przemyslaw Krol, Alex Bogdanov, Nandan Saha, Bruno Decraene,
Gurusiddesh Nidasesi, Kausik Majumdar, Zafar Ali, Swadesh Agarwal, Gurusiddesh Nidasesi, Kausik Majumdar, Zafar Ali, Swadesh Agarwal,
Jakob Heitz, Viral Patel, Peng Shaofu, Cheng Li, Martin Vigoureux, Jakob Heitz, Viral Patel, Peng Shaofu, Cheng Li, Martin Vigoureux,
John Scudder, Vincent Roca, Brian Haberman, Mohamed Boucadair, John Scudder, Vincent Roca, Brian Haberman, Mohamed Boucadair,
Shunwan Zhuang, Andrew Alston, Jeffrey (Zhaohui) Zhang, Nagendra Shunwan Zhuang, Andrew Alston, Jeffrey (Zhaohui) Zhang, Nagendra
Nainar, Rajesh Melarcode Venkateswaran, Nat Kao, Boris Hassanov, and Nainar, Rajesh Melarcode Venkateswaran, Nat Kao, Boris Hassanov,
Vincent Roca for their comments and review of this document. The Vincent Roca, and Russ Housley for their comments and review of this
authors would like to thank Susan Hares for her detailed shepherd document. The authors would like to thank Susan Hares for her
review that helped in improving the document. detailed shepherd review that helped in improving the document.
10. Contributors 10. Contributors
Eric Rosen Eric Rosen
Juniper Networks Juniper Networks
US US
Email: erosen@juniper.net Email: erosen@juniper.net
Arjun Sreekantiah Arjun Sreekantiah
skipping to change at page 40, line 9 skipping to change at page 40, line 9
A., and P. Mattes, "Segment Routing Policy Architecture", A., and P. Mattes, "Segment Routing Policy Architecture",
RFC 9256, DOI 10.17487/RFC9256, July 2022, RFC 9256, DOI 10.17487/RFC9256, July 2022,
<https://www.rfc-editor.org/info/rfc9256>. <https://www.rfc-editor.org/info/rfc9256>.
11.2. Informational References 11.2. Informational References
[I-D.ietf-idr-bgp-ls-sr-policy] [I-D.ietf-idr-bgp-ls-sr-policy]
Previdi, S., Talaulikar, K., Dong, J., Gredler, H., and J. Previdi, S., Talaulikar, K., Dong, J., Gredler, H., and J.
Tantsura, "Advertisement of Segment Routing Policies using Tantsura, "Advertisement of Segment Routing Policies using
BGP Link-State", Work in Progress, Internet-Draft, draft- BGP Link-State", Work in Progress, Internet-Draft, draft-
ietf-idr-bgp-ls-sr-policy-05, 22 July 2024, ietf-idr-bgp-ls-sr-policy-06, 19 October 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp- <https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-
ls-sr-policy-05>. ls-sr-policy-06>.
[I-D.ietf-idr-bgp-model] [I-D.ietf-idr-bgp-model]
Jethanandani, M., Patel, K., Hares, S., and J. Haas, "YANG Jethanandani, M., Patel, K., Hares, S., and J. Haas, "YANG
Model for Border Gateway Protocol (BGP-4)", Work in Model for Border Gateway Protocol (BGP-4)", Work in
Progress, Internet-Draft, draft-ietf-idr-bgp-model-17, 5 Progress, Internet-Draft, draft-ietf-idr-bgp-model-18, 21
July 2023, <https://datatracker.ietf.org/doc/html/draft- October 2024, <https://datatracker.ietf.org/doc/html/
ietf-idr-bgp-model-17>. draft-ietf-idr-bgp-model-18>.
[I-D.ietf-idr-bgp-sr-segtypes-ext] [I-D.ietf-idr-bgp-sr-segtypes-ext]
Talaulikar, K., Filsfils, C., Previdi, S., Mattes, P., and Talaulikar, K., Filsfils, C., Previdi, S., Mattes, P., and
D. Jain, "Segment Routing Segment Types Extensions for BGP D. Jain, "Segment Routing Segment Types Extensions for BGP
SR Policy", Work in Progress, Internet-Draft, draft-ietf- SR Policy", Work in Progress, Internet-Draft, draft-ietf-
idr-bgp-sr-segtypes-ext-04, 30 July 2024, idr-bgp-sr-segtypes-ext-05, 27 September 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp- <https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-
sr-segtypes-ext-04>. sr-segtypes-ext-05>.
[I-D.ietf-spring-sr-policy-yang] [I-D.ietf-spring-sr-policy-yang]
Raza, S. K., Saleh, T., Shunwan, Z., Voyer, D., Durrani, Raza, S. K., Saleh, T., Shunwan, Z., Voyer, D., Durrani,
M., Matsushima, S., and V. P. Beeram, "YANG Data Model for M., Matsushima, S., and V. P. Beeram, "YANG Data Model for
Segment Routing Policy", Work in Progress, Internet-Draft, Segment Routing Policy", Work in Progress, Internet-Draft,
draft-ietf-spring-sr-policy-yang-03, 4 March 2024, draft-ietf-spring-sr-policy-yang-03, 4 March 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-spring- <https://datatracker.ietf.org/doc/html/draft-ietf-spring-
sr-policy-yang-03>. sr-policy-yang-03>.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
 End of changes. 17 change blocks. 
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