Skip to main content

SR Policies Extensions for Network Resource Partition in BGP-LS
draft-ietf-idr-bgp-ls-sr-policy-nrp-00

Document Type Active Internet-Draft (idr WG)
Authors Ran Chen , Jie Dong , Detao Zhao , Liyan Gong , Yongqing Zhu , Ran Pang
Last updated 2024-10-02 (Latest revision 2024-08-14)
Replaces draft-chen-idr-bgp-ls-sr-policy-nrp
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Formats
Additional resources Mailing list discussion
Stream WG state WG Document
Document shepherd (None)
IESG IESG state I-D Exists
Consensus boilerplate Unknown
Telechat date (None)
Responsible AD (None)
Send notices to (None)
draft-ietf-idr-bgp-ls-sr-policy-nrp-00
IDR                                                              R. Chen
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                                 J. Dong
Expires: 13 February 2025                                         Huawei
                                                                 D. Zhao
                                                         ZTE Corporation
                                                                 L. Gong
                                                            China mobile
                                                                  Y. Zhu
                                                           China Telecom
                                                                 R. Pang
                                                            China Unicom
                                                          12 August 2024

    SR Policies Extensions for Network Resource Partition in BGP-LS
                 draft-ietf-idr-bgp-ls-sr-policy-nrp-00

Abstract

   A Network Resource Partition (NRP) is a subset of the network
   resources and associated policies on each of a connected set of links
   in the underlay network.  An NRP ID is an important network resource
   attribute associated with the Segment Routing (SR) policy and needs
   to be reported to the external components.  This document defines a
   new TLV which enables the headend to report the NRP which the SR
   Policy Candidate Path (CP) is associated with using Border Gateway
   Protocol Link-State (BGP-LS).

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 13 February 2025.

Chen, et al.            Expires 13 February 2025                [Page 1]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Carrying NRP TLV in BGP-LS  . . . . . . . . . . . . . . . . .   3
   3.  Scalability Considerations  . . . . . . . . . . . . . . . . .   5
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  Informative References  . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Segment Routing (SR) 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.

Chen, et al.            Expires 13 February 2025                [Page 2]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

   [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.  For SR Policy with IPv6 data plane,
   the approach to encapsulate the NRP ID in IPv6 Hop-by-Hop Options
   header is defined in [I-D.ietf-6man-enhanced-vpn-vtn-id].  For SR
   Policy with MPLS data plane, one approach to encapsulate the NRP ID
   to the packet is defined in [I-D.li-mpls-mna-nrp-selector].

   [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.

   [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 subset of the network
   resources and associated policies on each of a connected set of links
   in the underlay network.  The SR policy indicates the forwarding path
   of the data packet, and the NRP ID indicates the reserved resources
   along the path specified by the SR policy.  By associating the SR
   policy with a specific NRP, the forwarding path and resource
   reservation along the path are ensured.  BGP-LS reports the
   association between SR Policy Candidate Path (CP) and NRP-ID, which
   is used to synchronize the association information between the SR
   Policy CP and the NRP-ID.

   This document defines a new TLV which enables the headend to report
   the NRP which the SR Policy CP is associated with 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

   A SR Policy CP may be instantiated with a specific NRP on the headend
   node via a local configuration, PCEP, or BGP SR Policy signaling.
   Then the state and attributes of the NRP associated with the
   candidate path of SR policy can be distributed to the controller.

Chen, et al.            Expires 13 February 2025                [Page 3]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

   In order to collect configuration and states of the NRP SR policy,
   this document defines a new SR Policy state TLV called the NRP TLV
   which enables 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 these TLVs is advertised for a
   given SR Policy 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:

   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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         NRP ID (4 octets)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   Type: TBD.

   Length: 8.  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.  NRP ID is planned
   by network operator.

Chen, et al.            Expires 13 February 2025                [Page 4]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

3.  Scalability Considerations

   The mechanism specified in this document defines a mechanism for the
   headend of the SR policy to report configuration and states of an SR
   policy carrying the NRP information by using BGP-LS.  Although the
   proposed mechanism allows an NRP may support many SR policies, in
   normal case the association between the SR Policy and the NRP is
   considered to be 1:1.  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, the relationship
   between the SR Policy and the NRP is relatively stable and does not
   change status frequently.  On the other hand 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 Susan Hares, Joel Halpern, Ketan
   Talaulikar, Vishnu Pavan Beeram, Adrian Farrel, and Changwang Lin for
   their review and discussion of this document.

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].

Chen, et al.            Expires 13 February 2025                [Page 5]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

   Additionally, it may be considered that reporting the NRP ID in
   association with the SR policy constitutes a risk to confidentiality
   of mission-critical or commercially sensitive information about the
   network.  It is the responsibility of the network operator to ensure
   that only trusted nodes (that include both routers and controller
   applications) within the SR domain are configured to receive such
   information.

7.  Informative References

   [I-D.ietf-6man-enhanced-vpn-vtn-id]
              Dong, J., Li, Z., Xie, C., Ma, C., and G. S. Mishra,
              "Carrying Network Resource Partition (NRP) Information in
              IPv6 Extension Header", Work in Progress, Internet-Draft,
              draft-ietf-6man-enhanced-vpn-vtn-id-07, 8 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-6man-
              enhanced-vpn-vtn-id-07>.

   [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-05, 22 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-
              ls-sr-policy-05>.

   [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-01, 28 June
              2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
              idr-sr-policy-nrp-01>.

   [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-05, 5 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              nrp-scalability-05>.

   [I-D.li-mpls-mna-nrp-selector]
              Li, T., Drake, J., Beeram, V. P., Saad, T., and I. Meilik,
              "MPLS Network Actions for Network Resource Partition
              Selector", Work in Progress, Internet-Draft, draft-li-
              mpls-mna-nrp-selector-01, 25 June 2024,
              <https://datatracker.ietf.org/doc/html/draft-li-mpls-mna-
              nrp-selector-01>.

Chen, et al.            Expires 13 February 2025                [Page 6]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

   [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

Chen, et al.            Expires 13 February 2025                [Page 7]
Internet-Draft          BGP-LS SR policy for NRP             August 2024

   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

Chen, et al.            Expires 13 February 2025                [Page 8]