IDR R. Chen
Internet-Draft ZTE Corporation
Intended status: Standards Track J. Dong
Expires: 19 November 2024 Huawei
D. Zhao
ZTE Corporation
L. Gong
China mobile
Y. Zhu
China Telecom
R. Pang
China Unicom
18 May 2024
SR Policies Extensions for Network Resource Partition in BGP-LS
draft-chen-idr-bgp-ls-sr-policy-nrp-08
Abstract
A Network Resource Partition (NRP) is a network resource attribute
associated with the SR policy. It is also an important attribute of
the SR policy and needs to be reported to the external components.
This document defines a new TLV which enable the headend to report
the configuration and the states of an SR policy carrying the NRP
information by using 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 November 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Carrying NRP TLV in BGP-LS . . . . . . . . . . . . . . . . . 3
3. Scalability Considerations . . . . . . . . . . . . . . . . . 4
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Informative References . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Segment Routing Policy [RFC9256] is an ordered list of segments (i.e.
instructions) that represent a source-routed policy. Packet flows
are steered into a SR Policy on a node where it is instantiated
called a headend node. The packets steered into an SR Policy carry
an ordered list of segments associated with that SR Policy.
[RFC9543] provides the definition of IETF network slice for use
within the IETF and discusses the general framework for requesting
and operating IETF Network Slices, their characteristics, and the
necessary system components and interfaces.It also introduces the
concept Network Resource Partition (NRP), which is a subset of the
resources and associated policies in the underlay network.
[I-D.ietf-teas-nrp-scalability] introduces a scalable data plane
approach to support Network Slice is to carry a dedicated NRP ID in
the data packet to identify the NRP the packet belongs to, so that
the packet can be processed and forwarded using the subset of network
resources allocated to the NRP.
[I-D.ietf-idr-sr-policy-nrp] defines the extensions to BGP SR policy
to specify the NRP which the SR Policy candidate path is associated
with.
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[I-D.ietf-idr-bgp-ls-sr-policy] describes a mechanism to distribute
SR policy information to external components using BGP-LS. SR policy
information can be used by external components for path computation,
re-optimization, service placement, network visualization, etc.
A Network Resource Partition (NRP) is a network resource attribute
associated with the SR policy. It is also an important attribute of
the SR policy and needs to be reported to the external components.
The notification of SR policy with NRP information is also used by
external components for path computation, re-optimization, service
placement, network visualization, etc. This document defines a new
TLV which enable the headend to report the configuration and the
states of an SR policy carrying the NRP information by using 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. Carrying NRP TLV in BGP-LS
In order to collect configuration and states of the NRP SR policy,
this document defines a new SR Policy state TLV which enable the
headend to report the state at the SR Policy CP level.
This TLV is carried in the optional non-transitive BGP Attribute
"LINK_STATE Attribute" defined in [RFC9552]associated with the SR
Policy CP NLRI type.
This TLV is optional and only one this TLV is advertised for a given
CP. If multiple TLVs are present, then the first one is considered
valid and the rest are ignored as describe in
[I-D.ietf-idr-bgp-ls-sr-policy].
The TLV has the following format:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flag | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRP ID (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: TBD.
Length: The total length of the value field not including Type and
Length fields.
Flag: 2-octet flag field. None is defined at this stage. The flags
SHOULD be set to zero on transmission and MUST be ignored on receipt.
RESERVED: 2-octet reserved bits. It SHOULD be set to zero on
transmission and MUST be ignored on receipt.
NRP ID: 4-octet domain significant identifier of Network Resource
Partition. Value 0 and 0xFFFFFFFF are reserved.
3. Scalability Considerations
The mechanism specified in this document defines the headend to
report configuration and states of an SR policy carrying the NRP
information by using BPG-LS. BGP-LS SR Policy is used to report the
SR Policy attributes and status. As the number of NRP increases, the
number of SR Policies would also increase accordingly, and the status
reported by the headend increases accordingly. However, this will
only cause an increase in the status reporting information of the
head node, the impacts to the BGP control plane are considered
acceptable.
4. Acknowledgements
The authors would like to thank Changwang Lin for their review and
discussion of this document.
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5. IANA Considerations
IANA maintains a registry group called "Border Gateway Protocol -
Link State (BGP-LS) Parameters" with a registry called "BGP-LS NLRI
and Attribute TLVs". The following TLV codepoints are suggested (for
early allocation by IANA):
Codepoint Description Reference
----------------------------------------------------------
TBD NRP This document
6. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See the "Security
Considerations"section of [RFC4271] for a discussion of BGP security.
Security considerations for acquiring and distributing BGP-LS
information are discussed in [RFC9552]. Security considerations for
acquiring and distributing BGP-LS SR Policy information are discussed
in [I-D.ietf-idr-sr-policy-nrp].
7. Informative References
[I-D.ietf-idr-bgp-ls-sr-policy]
Previdi, S., Talaulikar, K., Dong, J., Gredler, H., and J.
Tantsura, "Advertisement of Segment Routing Policies using
BGP Link-State", Work in Progress, Internet-Draft, draft-
ietf-idr-bgp-ls-sr-policy-04, 20 March 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-
ls-sr-policy-04>.
[I-D.ietf-idr-sr-policy-nrp]
Dong, J., Hu, Z., and R. Pang, "BGP SR Policy Extensions
for Network Resource Partition", Work in Progress,
Internet-Draft, draft-ietf-idr-sr-policy-nrp-00, 17
December 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-idr-sr-policy-nrp-00>.
[I-D.ietf-teas-nrp-scalability]
Dong, J., Li, Z., Gong, L., Yang, G., and G. S. Mishra,
"Scalability Considerations for Network Resource
Partition", Work in Progress, Internet-Draft, draft-ietf-
teas-nrp-scalability-04, 4 March 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
nrp-scalability-04>.
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[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>.
[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>.
[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>.
[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>.
[RFC9543] Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S.,
Makhijani, K., Contreras, L., and J. Tantsura, "A
Framework for Network Slices in Networks Built from IETF
Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024,
<https://www.rfc-editor.org/info/rfc9543>.
[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>.
Authors' Addresses
Ran Chen
ZTE Corporation
Nanjing
China
Email: chen.ran@zte.com.cn
Jie Dong
Huawei
Beijing
China
Email: jie.dong@huawei.com
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Detao Zhao
ZTE Corporation
Nanjing
China
Email: zhao.detao@zte.com.cn
Liyan Gong
China mobile
Beijing
China
Email: gongliyan@chinamobile.com
Yongqing Zhu
China Telecom
Guangzhou
China
Email: zhuyq8@chinatelecom.cn
Ran Pang
China Unicom
Beijing
China
Email: pangran@chinaunicom.cn
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