IDR                                                             F. Yang
Internet Draft                                             China Mobile
Intended status: Standards Track                                 C. Lin
Expires: June 30, 2025                             New H3C Technologies
                                                      December 30, 2024
BGP SR Policy Extensions for Weight Time Range draft-yang-idr-sr-policy-weight-timerange-01


Abstract

Segment Routing is a source routing paradigm that explicitly indicates the forwarding path for packets at the ingress node. An SR Policy is a set of candidate paths, each consisting of one or more segment lists.

In the scenario where there are multiple segment list paths, traffic load balancing can be achieved based on the weight value assigned to each path. Typically, the weight value for each path is fixed. This document defines an extension of BGP SR Policy for setting the weight value for each path based on time range.

Status of this Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on June 30, 2025.

Copyright Notice

Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.
Lin, et al.             Expires June 30, 2025                 [Page 1]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
Table of Contents


1. Introduction...................................................2
1.1. Requirements Language.....................................3
2. Weight Time Range in SR Policy.................................3
2.1. Weight Time Range Sub-TLV.................................4
3. Security Considerations........................................7
4. IANA Considerations............................................7
5. References.....................................................7
5.1. Normative References......................................7
5.2. Informative References....................................8
Authors' Addresses................................................9
1. Introduction
Segment routing (SR) [RFC8402] is a source routing paradigm that explicitly indicates the forwarding path for packets at the ingress node. The ingress node steers packets into a specific path according to the Segment Routing Policy (SR Policy) as defined in [RFC9256]. In order to distribute SR policies to the headend, [I-D.ietf-idr-sr- policy-safi] specifies a mechanism by using BGP.

In the scenario where there are multiple segment list paths, traffic load balancing can be achieved based on the weight value assigned to each path. Typically, the weight value for each path is fixed.

The load on network paths typically exhibits periodic variations throughout the day. In order to effectively utilize network bandwidth, it is important for the weight parameter in SR Policy- based traffic forwarding to be adjustable over time rather than remaining constant.

This document introduces a BGP SR Policy extension to enable the setting of forwarding weight values for each path based on time, allowing for time-based adjustments of traffic forwarding paths.
Yang, et al.            Expires June 30, 2025                 [Page 2]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
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. Weight Time Range in SR Policy
As defined in [I-D.ietf-idr-sr-policy-safi], the SR policy encoding structure is as follows:

SR Policy SAFI NLRI: <Distinguisher, Policy-Color, Endpoint> Attributes:
Tunnel Encaps Attribute (23)
Tunnel Type: SR Policy
Binding SID SRv6 Binding SID Preference Priority Policy Name Policy Candidate Path Name Explicit NULL Label Policy (ENLP) Segment List Weight Segment Segment ...
...

SR policy with Weight Time Range is expressed as below:
Yang, et al.            Expires June 30, 2025                 [Page 3]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
SR Policy SAFI NLRI: <Distinguisher, Policy-Color, Endpoint> Attributes:
Tunnel Encaps Attribute (23)
Tunnel Type: SR Policy
Binding SID SRv6 Binding SID Preference Priority Policy Name Policy Candidate Path Name Explicit NULL Label Policy (ENLP) Segment List Weight Time Range Segment Segment ...
...

The Weight Time Range can be advertised using the Weight Time Range sub-TLV, as defined in Section 2.1.

Within the Segment List sub-TLV, an optional single Weight sub-TLV and zero or more Weight Time Range sub-TLVs can be carried. If both the Weight Sub-TLV and Weight Time Range Sub-TLV are present, the weight value specified in the Weight Time Range sub-TLV takes effect during the defined time range. For the remaining time, the weight value specified in the Weight Sub-TLV takes effect.
2.1. Weight Time Range Sub-TLV
The Weight Time Range sub-TLV is used to indicate the Weight Based on Time Range of the Segment List.

The Weight Time Range sub-TLV is optional and it can appear more than once inside the Segment List sub-TLV.

The Weight Time Range sub-TLV has the following format:
Yang, et al.            Expires June 30, 2025                 [Page 4]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
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      |     Flags     |   RESERVED    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             Weight                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | TimeRangeType |             RESERVED                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             Start                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             End                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             Weight                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | TimeRangeType |             RESERVED                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             Start                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             End                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             ...                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:

o Type: TBD.

o Length: 2 + Weight Number * (one TimeRange Weight Length).

o Flags: 1 octet of flags. None are defined at this stage. Flags SHOULD be set to zero on transmission and MUST be ignored on receipt.

o RESERVED: 1 octet of reserved bits. SHOULD be set to zero on
transmission and MUST be ignored on receipt.

o TimeRangeType: 1 octet. Type 1: Absolute Time

Type 2: Period Day Time

Type 3: Period Week Time

Type 4: Perion Month Time

Yang, et al.            Expires June 30, 2025                 [Page 5]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
o start/end: The format varies depending on the TimeRangeType.
Please refer to the detailed description below for the specific format.



Absolute Time format:
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             StartTime                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  StartYear                    |  StartMonth   |   StartDay    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             EndTime                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  EndYear                      |  EndMonth     |   EndDay      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   StartTime/EndTime: 4 octets.
hour(1octet)+Minute(1octet)+Second(1octet)+Reserved(1octet)


Period Day Time format:
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             StartTime                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             EndTime                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   StartTime/EndTime: 4 octets.
hour(1octet)+Minute(1octet)+Second(1octet)+Reserved(1octet)


Period Week Time format:
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             StartTime                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  StartDay     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             EndTime                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  EndDay       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   StartTime/EndTime: 4 octets.
hour(1octet)+Minute(1octet)+Second(1octet)+Reserved(1octet) StartDay/EndDay: 1 octet, 0-6 Period Month Time format:


Yang, et al.            Expires June 30, 2025                 [Page 6]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024



   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             StartTime                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  StartDay     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             EndTime                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  EndDay       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   StartTime/EndTime: 4 octets.
hour(1octet)+Minute(1octet)+Second(1octet)+Reserved(1octet) StartDay/EndDay: 1 octet, 1-31

3. Security Considerations
The security requirements and mechanisms described in [I-D.ietf-idr- sr-policy-safi] also apply to this document.

This document does not introduce any new security consideration.
4. IANA Considerations
This document defines a new Sub-TLV in the registry "SR Policy Weight Time Range Sub-TLVs" [I-D.ietf-idr-sr-policy-safi]:
   Value    Description                         Reference
   -------------------------------------------------------
   TBA      Weight Time Range sub-TLV           This document

5. References

5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, May 2017

[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, <https://www.rfc-editor.org/info/rfc8402>.


Yang, et al.            Expires June 30, 2025                 [Page 7]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
[I-D.ietf-idr-sr-policy-safi] Previdi, S., Filsfils, C., Talaulikar,
K., Mattes, P., and D. Jain, "Advertising Segment Routing Policies in BGP", Work in Progress, Internet-Draft, draft- ietf-idr-sr-policy-safi-04, 30 April 2024, <https://datatracker.ietf.org/doc/html/draft-ietf-idr-sr- policy-safi-04>.
5.2. Informative References
[RFC9256] Filsfils, C., Talaulikar, K., Ed., Voyer, D., Bogdanov,
A., and P. Mattes, "Segment Routing Policy Architecture", RFC 9256, DOI 10.17487/RFC9256, July 2022, <https://www.rfc-editor.org/info/rfc9256>.

[I-D.ietf-pce-multipath] Koldychev, M., Sivabalan, S., Saad, T.,
Beeram, V. P., Bidgoli, H., Yadav, B., Peng, S., and G. S. Mishra, "PCEP Extensions for Signaling Multipath Information", Work in Progress, Internet-Draft, draft- ietf-pce-multipath-09, 24 July 2023, <https://datatracker.ietf.org/doc/html/draft-ietf-pce- multipath-09>.
Yang, et al.            Expires June 30, 2025                 [Page 8]

Internet-Draft      BGP SR Policy Weight Time Range      December 2024
Authors' Addresses

Feng Yang China Mobile Beijing China Email: yangfeng@chinamobile.com


Changwang Lin New H3C Technologies China Email: linchangwang.04414@h3c.com



































Yang, et al. Expires June 30, 2025 [Page 9]


Ad
Translate documents to 日本語, svenska, Nederlands, Deutsch, français, русский, italiano, español, Tiếng Việt, polski, português, 中文, українська, català, norsk, فارسی, suomi, Bahasa Indonesia, العربية, čeština, 한국어, Bahasa Melayu, magyar, română, српски and other languages.
inserted by FC2 system