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Resource Guarantee for SRv6 Policies
draft-cheng-spring-srv6-policy-resource-gurantee-00

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This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors Weiqiang Cheng , Jiang Wenying , Ran Chen , Detao Zhao , Changwang Lin
Last updated 2023-09-27
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draft-cheng-spring-srv6-policy-resource-gurantee-00
SPRING Working Group                                            W. Cheng
Internet-Draft                                                  W. Jiang
Intended status: Standards Track                            China Mobile
Expires: 31 March 2024                                           R. Chen
                                                                 D. Zhao
                                                         ZTE Corporation
                                                                  C. Lin
                                                    New H3C Technologies
                                                       28 September 2023

                  Resource Guarantee for SRv6 Policies
          draft-cheng-spring-srv6-policy-resource-gurantee-00

Abstract

   This document defines a new SRv6 Endpoint behavior which can be used
   to associate with a set of network resource partition (e.g.
   bandwidth, buffer and queue resources ) Programming, called End.NRP.
   By using the End.NRP SID to build its segment list , the SRv6 policy
   has the capability to program network resources and achieve strict
   SLA guarantees.

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
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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 31 March 2024.

Copyright Notice

   Copyright (c) 2023 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.

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   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
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  End.NRP Behavior  . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Use Cases for End.NRP behavior  . . . . . . . . . . . . . . .   3
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The concept of Network Resource Partition is introduced in
   [I-D.ietf-teas-ietf-network-slices].  A Network Resource Partition
   (NRP) is a set of network resources that are allocated from the
   underlay network to carry a specific set of network traffic and meet
   the required SLOs and SLEs.

   Segment Routing (SR) [RFC8402] leverages the source routing paradigm.
   An ingress node steers a packet through an ordered list of
   instructions, called "segments".  Each one of these instructions
   represents a function to be called at a specific location in the
   network.  A function is locally defined on the node where it is
   executed and may range from simply moving forward in the segment list
   to any complex user-defined behavior.

   SR Policy is an ordered list of segments (i.e., instructions) that
   represent a source-routed policy.  The packets steered into an SR
   Policy have an ordered list of segments associated with that SR
   Policy.

   Since the SRv6 Endpoint behavior defined in [RFC8986] are not
   associated with a set of network resource partition of the interface
   for slices/slice aggregate(e.g.End.X just forwards to an endpoint
   with cross-connect to a 'layer-3 adjacency' or L2 bundles).
   Therefore, SRv6 policies can't achieve strict SLA guarantees.

   [I-D.ietf-spring-resource-aware-segments]extends the SR paradigm by
   associating SIDs with network resource attributes.  On the basis of
   [I-D.ietf-spring-resource-aware-segments], this document defines a

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   new SRv6 Endpoint behavior which can be used to associate with a set
   of network resource partition (e.g. bandwidth, buffer and queue
   resources ) Programming, called End.NRP.  By using the End.NRP SID to
   build its segment list , the SRv6 policy has the capability to
   program network resources and achieve strict SLA guarantees.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

3.  End.NRP Behavior

   This section defines a new SRv6 Endpoint behavior which can be used
   to associate with a set of snetwork resource partition (e.g.
   bandwidth, buffer and queue resources ) Programming, called End.NRP.
   The End.NRP is a variant of the End.X behavior defined in [RFC8986].

   Any SID instance of End.NRP behavior is associated with two sets:J1
   and J2.

           J1:one or more L3 adjacencies or L2 bundles
           J2:NRP of J1

   When N receives a packet destined to S and S is a local End.NRP SID,
   the line S15 from the End processing defined in [RFC8986] is replaced
   by the following:

        S15. Submit the packet to the IPv6 module for transmission to
                     the new destination via a member of J1, using the NRP
                         identified by J2

   This End.NRP SID can support the Penultimate Segment Pop (PSP) of the
   SRH, Ultimate Segment Pop (USP) of the SRH, and Ultimate Segment
   Decapsulation (USD) flavors defined in [RFC8986] either individually
   or in combinations.  The SRH processing of the End.NRP behavior with
   PSP, USP, and USD is the same as [RFC8986].

   This End.NRP SIDs can be allocated either by a centralized network
   controller or by the network nodes, and the End.NRP behavior can be
   announced using IGP or BGP-LS.  The detailed protocol extension will
   be described in a separate document.

4.  Use Cases for End.NRP behavior

   This section describes possible procedures for the End.NRP behavior.

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   A group of End.NRP SIDs can be allocated for the set of network
   resources associated with the SRv6 Policies, so that different
   End.NRP SIDs can be used to steer service traffic into different set
   of link resources (e.g. bandwidth, buffer and queue resources) in
   packet forwarding.

   Below is the possible procedures:

   1.  The controller get the topology information, calculate the SR
       Policy path based on SLA.

   2.  The controller cooperates with the network nodes to complete
       resource reservation and the End.NRP SID allocation along the SR
       Policy path.

   3.  The controller use the End.NRP SID to build the SID list for the
       explicit path.

   4.  Then the controller inform the headend the resource guaranteed
       path by various means including: via BGP
       [I-D.ietf-idr-segment-routing-te-policy], configuration or PCEP
       [RFC8664] [I-D.ietf-pce-segment-routing-policy-cp].

SRv6 Policy1 from PE1 to PE2
segment list <End.NRP11, End.NRP12, End.NRP13>

SRv6 Policy2 from PE1 to PE2
segment list <End.NRP21, End.NRP22, End.NRP23>

                                   End.NRP12
                                   End.NRP22
                                   * * * * * *
                                                             P1-----------P2
                                                           */*|* * * * * * |\ * *
                                                          */* |            | \ * *
                    CE11------   End.NRP11|            |End.NRP13  ------ CE12
                      \  End.NRP21|            |End.NRP23 /
                       \   */ *   |            |    \* * /
                       PE1  \     |            |      PE2
                       /     \    |            |    /    \
                      /       \   |            |   /      \------ CE2
            CE21------         \  |            |  /
                                                \ |            | /
                                         P3------------P4

                               Figure 1

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   Figure 1 shows an example for the End.NRP behavior.

   As shown in Figure 1, there are two customers with different leased
   line requirements from PE1 to PE2:

      leased line1 : 1G BandWidth with strict SLA guarantee.

      leased line2 : 2G BandWidth with strict SLA guarantee.

   Below is the possible procedures:

   1.  The controller get the topology information, calculate the SRv6
       Policy 1 and SRv6 Policy 2 based on SLA.

   2.  The controller cooperates with the network nodes to complete
       resource reservation and the End.NRP SID allocation along the
       SRv6 Policy1 and SRv6 Policy 2.  Taking the interface PE1-P1 of
       SRv6 node PE1 along the SRv6 Policy 1 as an example, two
       different NRPs(e.g. two dedicated queues) are partitioned from
       the network resources of the physical link PE1-P1 (GE1/0/0).  -
       The NRP(Queue1:1G BW)of link PE1- P1 is reserved and associated
       with End.NRP11 - The NRP(Queue2:2G BW)of link PE1- P1 is reserved
       and associated with End.NRP21.

   3.  The controller uses the End.NRP11, End.NRP12, and End.NRP13 to
       build the SID list for the SRv6 Policy1 and use the End.NRP21,
       End.NRP22, and End.NRP23 to build the SID list for the SRv6
       Policy 2.

   4.  Then the controller inform the headend the segment list of SRv6
       Policy 1 and the segment list of SRv6 Policy 2 by various means
       including: via BGP [I-D.ietf-idr-segment-routing-te-policy],
       configuration or PCEP [RFC8664]
       [I-D.ietf-pce-segment-routing-policy-cp].

   The traffic from customer1 and customer2 will be forwarded to PE2
   through the NRPs previously reserved for each hop link on the path of
   SRv6 Policy1 and SRv6 Policy2 respectively, thus Customer 1 and
   Customer 2 are provided with end-to-end 1G bandwidth resources and 2G
   bandwidth resources respectively, and private line services are
   guaranteed by strict SLAs.

5.  Acknowledgements

   TBD.

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6.  IANA Considerations

   The document defines a new SRv6 Endpoint behavior called End.NRP.

   This I-D requests the IANA to allocate, within the "SRv6 Endpoint
   Behaviors" sub-registry belonging to the top-level "Segment-routing
   with IPv6 dataplane (SRv6) Parameters" registry, the following
   allocations:

           Value              Endpoint Behavior               Reference
       ---------------------------------------------------------------
        TBD1                End.NRP                      [This.ID]

7.  Security Considerations

   TBD.

8.  Normative References

   [I-D.ietf-idr-segment-routing-te-policy]
              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-segment-
              routing-te-policy-25, 26 September 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-idr-
              segment-routing-te-policy-25>.

   [I-D.ietf-pce-segment-routing-policy-cp]
              Koldychev, M., Sivabalan, S., Barth, C., Peng, S., and H.
              Bidgoli, "PCEP extension to support Segment Routing Policy
              Candidate Paths", Work in Progress, Internet-Draft, draft-
              ietf-pce-segment-routing-policy-cp-12, 24 July 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-pce-
              segment-routing-policy-cp-12>.

   [I-D.ietf-spring-resource-aware-segments]
              Dong, J., Bryant, S., Miyasaka, T., Zhu, Y., Qin, F., Li,
              Z., and F. Clad, "Introducing Resource Awareness to SR
              Segments", Work in Progress, Internet-Draft, draft-ietf-
              spring-resource-aware-segments-07, 31 May 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-spring-
              resource-aware-segments-07>.

   [I-D.ietf-teas-ietf-network-slices]
              Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
              K., Contreras, L. M., and J. Tantsura, "A Framework for
              Network Slices in Networks Built from IETF Technologies",

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              Work in Progress, Internet-Draft, draft-ietf-teas-ietf-
              network-slices-25, 14 September 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              ietf-network-slices-25>.

   [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>.

   [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>.

   [RFC8664]  Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
              and J. Hardwick, "Path Computation Element Communication
              Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
              DOI 10.17487/RFC8664, December 2019,
              <https://www.rfc-editor.org/info/rfc8664>.

   [RFC8986]  Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
              D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
              (SRv6) Network Programming", RFC 8986,
              DOI 10.17487/RFC8986, February 2021,
              <https://www.rfc-editor.org/info/rfc8986>.

Authors' Addresses

   Weiqiang Cheng
   China Mobile
   China
   Email: chengweiqiang@chinamobile.com

   Wenying Jiang
   China Mobile
   China
   Email: jiangwenying@chinamobile.com

   Ran Chen
   ZTE Corporation
   Nanjing
   China
   Email: chen.ran@zte.com.cn

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   Detao Zhao
   ZTE Corporation
   Nanjing
   China
   Email: zhao.detao@zte.com.cn

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

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