Network Working Group                                              B. Wu
Internet-Draft                                                  D. Dhody
Intended status: Standards Track                     Huawei Technologies
Expires: 29 March 2023                                      M. Boucadair
                                                                  Orange
                                                                Y. Cheng
                                                            China Unicom
                                                                 L. Gong
                                                            China Mobile
                                                       25 September 2022


        A YANG Data Model for Network Resource Partitions (NRPs)
                       draft-wd-teas-nrp-yang-02

Abstract

   This document defines a YANG data model of Network Resource Partition
   (NRP) for the NRP management operation.  The model can be used for
   the realization of IETF Network Slice Services.

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 29 March 2023.

Copyright Notice

   Copyright (c) 2022 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



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   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
     2.1.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   3
   3.  NRP Modelling Requirements  . . . . . . . . . . . . . . . . .   3
   4.  NRP Modelling Considerations  . . . . . . . . . . . . . . . .   4
     4.1.  NRP Model Usage . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  NRP Modeling Design . . . . . . . . . . . . . . . . . . .   8
   5.  Description of NRP YANG Module  . . . . . . . . . . . . . . .  10
   6.  NRP YANG Module Tree  . . . . . . . . . . . . . . . . . . . .  11
   7.  NRP Yang Module . . . . . . . . . . . . . . . . . . . . . . .  13
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  24
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  25
   10. Contributor . . . . . . . . . . . . . . . . . . . . . . . . .  25
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  26
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  26
     11.2.  Informative References . . . . . . . . . . . . . . . . .  27
   Appendix A.  An Example . . . . . . . . . . . . . . . . . . . . .  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  31

1.  Introduction

   [I-D.ietf-teas-ietf-network-slices] defines IETF Network Slice
   services that provide connectivity coupled with network resources
   commitment between a number of Service Demarcation Points (SDPs) over
   a shared network infrastructure and, for scalability and agility
   concerns, defines Network Resource Partition (NRP) to host one or a
   group of network slice services according to characteristics
   including Service Level Objectives (SLOs) and Service Level
   Expectations (SLEs).  [I-D.ietf-teas-nrp-scalability] analyzes the
   scalability issues of network slice services in detail and suggests
   candidate technologies of control and forwarding planes of the NRP.

   This document defines a YANG module of NRP that the IETF NSC (Network
   Slice controller) can use to manage NRP instances to realize the
   network slicing services.  According to the YANG model classification
   of [RFC8309], the NRP model is a network configuration model.

2.  Terminology

   The following terms are defined in [RFC6241] and are used in this
   specification:




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   *  configuration data

   *  state data

   The following terms are defined in [RFC7950] and are used in this
   specification:

   *  augment

   *  data model

   *  data node

   The terminology for describing YANG data models is found in
   [RFC7950].

2.1.  Tree Diagrams

   The tree diagram used in this document follows the notation defined
   in [RFC8340].

3.  NRP Modelling Requirements

   [I-D.ietf-teas-ietf-network-slices] section 6.1 introduces the
   concept of NRP, which is a collection of resources (bufferage,
   queuing, scheduling, etc.) in the underlay network to provide
   specific SLOs and SLEs for connectivity constructs of IETF Network
   Slice services.  [I-D.ietf-teas-ns-ip-mpls] provides some solutions
   to realize network slicing in IP/MPLS networks.  Additionally
   [I-D.ietf-teas-nrp-scalability] provides analysis and possible
   optimizations of the control plane and data plane of NRP in IP/MPLS
   networks for better scalability.  The following are some common NRP
   attributes for NRP management identified based on the analysis:

   *  NRP instantiation

      -  NRP partition type: Refers to various NRP resource partition
         methods, such as control plane partition, data plane partition,
         or hybrid partition, etc.

      -  NRP topology generation method: Topologies can be created using
         multiple methods.  For example, NRP links can be all links in
         the underlay topology, or explicitly selected links from the
         topology or implicitly selected from the various existing
         topologies.

      -  NRP resource reservation: Reserves link resources for the NRP,
         including bandwidth, queuing, and other resource partitioning.



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      -  NRP control plane: Mechanisms that provide routing and
         forwarding to one or a group of network slice traffic to ensure
         the corresponding SLO and SLE through NRP link resources, e.g.
         distributed control plane described in
         [I-D.ietf-teas-nrp-scalability], or NRP aware TE (NRP-TE)
         described in [I-D.ietf-teas-ns-ip-mpls].

      -  NRP data plane: Dataplane identifier carried in a data packet,
         which is used to mark the link resources and behaviors
         allocated to the NRP.

      -  NRP steering policy: Policies for steering slice traffic to the
         NRP.

   *  NRP modification or updates: Modifications or additions to
      existing NRP-allocated resources, e.g. some congested links need
      to be expanded.

   *  NRP monitoring: NRP-allocated resources, including NRP-specific
      link or node SID, link bandwidth usage, link delay, and packet
      loss status, etc.

4.  NRP Modelling Considerations

   An NRP is a subset, or all, of resources allocated from a physical
   network or logical network.  Depending on the SLO and SLE
   requirements of the slicing service and also the available resources
   of the operator's network, there are several options of creating an
   NRP.  One option is that each physical link is allocated to only one
   specific NRP, and different NRPs do not share any physical link.  One
   more typical option is that multiple NRPs share the same physical
   links, and each NRP is built with virtual links with a certain subset
   of the bandwidth available on the physical links to provide network
   resource isolation.

   In addition to specifying resource allocation from the underlay
   network, an NRP also needs to have associated control plane and
   forwarding plane technologies, which can provide specific routing and
   forwarding so that the traffic received from NRP edge nodes that is
   characterized to match the NRP traffic classification rule is
   constrained to the NRP exclusive topology and resource allocation.
   The NRP allows network operators to manage the resources of IETF
   Network Slices which are used to provide network slice service
   traffic with specific SLOs and SLEs.

   As defined in [I-D.ietf-teas-nrp-scalability], the draft discusses
   NRP control plane and data plane requirements in different
   provisioning scenarios, and describes that the NRP control plane is



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   used to exchange network resource attributes and associated logical
   topology information between nodes of the NRP so that NRP-specific
   routing and forwarding tables could be generated.  For the NRP
   control plane, distributed control plane mechanism, such as Multi-
   topology, Flex-Algo or centralized SDN or hybrid combination could be
   defined.  To help with forwarding entries, several data-plane
   encapsulation options are also discussed to carry NRP information in
   the NRP traffic packets.  The example NRP data plane identifier could
   be the IPv6 addresses or the MPLS forwarding labels or dedicated NRP
   data-plane identifiers.

   An example of NRP instances and a physical network is illustrated in
   Figure 1.  In the example, each NRP instance has a customized network
   topology comprised of a set of links and nodes in the physical
   network.  In control plane, each NRP could be associated with a
   multi-topology or a Flex-Algo.  And it also has its own forwarding
   plane resources and identifiers which provide NRP-specific packet
   forwarding.

































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               ++++   ++++   ++++
               +--+===+--+===+--+
               +--+===+--+===+--+
               ++++   +++\\  ++++
                ||     || \\  ||             Physical
                ||     ||  \\ ||             Network
        ++++   ++++   ++++  \\+++   ++++
        +  +===+--+===+--+===+--+===+  +
        +  +===+--+===+--+===+--+===+  +
        ++++   ++++   ++++   ++++   ++++
         PE1                         PE2
                         |
                        \|/

                o----o-----o
               /          /              NRP-1
        o-----o-----o----o----o


                o----o
               /    / \                  NRP-2
        o-----o----o---o------o

                                          ...

                     o----o
                    /    /               NPR-n
        o-----o----o----o-----o

           o   is a virtual node
           --- is a virtual link

                          Figure 1: An NRP Example


   [I-D.ietf-teas-ietf-network-slices] also describes the management of
   the NRP.  After an NRP created, the NRP may need to be refined and
   modified as the network status and slice services change, and could
   be extended if necessary to meet the customers' demands.  In addition
   to configuration management, the NRP should also provide detailed
   monitoring information about underlying resources to further provide
   monitoring for the hosted slice services.









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4.1.  NRP Model Usage

   One major application of network slices is 5G services.  Figure 2
   shows the use of the NRP model to realize the IETF Network Slice for
   the 5G use case, based on the reference framework defined in
   [I-D.ietf-teas-ietf-network-slices].  The figure shows that the NSC
   uses the L3VPN network model (L3NM) [RFC9182] and the NRP model to
   map to an IETF Network Slice service.  One possible method is to set
   the "underlay-transport" of the L3NM as an NRP instance, which is
   used to specify the NRP to carry the VPN traffic.  In this way, the
   NRP-specific resources, together with NRP control plane and
   forwarding plane technologies are used to ensure the SLO and SLE
   required by the traffic.  Similarly, the L2NM [RFC9291] can also be
   used to map an IETF Network Slice service to an underlying network.

         +------------------------------------------+
         |                 Customer                 |
         |                                          |
         +------------------------------------------+
                              A
                              | IETF Network Slice service interface
                              V
         +------------------------------------------+
         |    IETF Network Slice Controller (NSC)   |
         +------------------------------------------+
                              A
                     L3NM     | Network Configuration Interface
                    NRP Model V
         +------------------------------------------+
         |           Network Controller(s)          |
         +------------------------------------------+
                              A
                              |    Device model
                              V
      +------------------------------------------------+
                            Network

                    Figure 2: Reference Module Use Case

   In the process of realizing an IETF Network Slice service, the NSC
   can use a pre-built NRP instance or dynamically create one as one or
   a group of VPNs underlay construct.  Compared with current VPN
   underlay transport mechanisms, the NRP could provide resource
   isolation, topology constraints, and distributed and/ or centralized
   traffic engineering (TE).  For example, an NRP can use SR policies
   mechanisms, such as [I-D.dong-idr-sr-policy-nrp] to optimize the
   specific VPN traffic in the NRP topology while providing NRP shortest
   path forwarding for other VPN traffic.



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4.2.  NRP Modeling Design

   As defined in [I-D.ietf-teas-ietf-network-slices], a network resource
   partition (NRP) is a collection of resources in the underlay network.
   An NRP can have a dedicated topology or can use a shared topology
   with other NRPs.

   Therefore, an NRP is modeled as network topology defined in [RFC8345]
   with augmentations.  A new network type "nrp" is defined.  A network
   topology data instance containing the nrp network type, indicates an
   NRP instance.  The Figure 3 shows the relationship between this model
   and other topology models.

                 +-----------------------+
                 |Network Topology Model |
                 |       RFC8345         |
                 +-----------------------+
                        |
          +-------------+-------------+-------------+
          |             |             |             |
          V             V             V             V
      +----------+ ............  ............  ............
      |  Network | :   L3     :  :    TE    :  :    L2    :
      | Resource | :Topology  :  : Topology :  : Topology :
      | Partition| :  Model   :  :   Model  :  :   Model  :
      |   Model  | :..........:  :..........:  :..........:
      +----------+

                      Figure 3: NRP Model Relationship

   The container "nrp" under 'network' of [RFC8345] defines global
   parameters for an NRP, which defines NRP partition type, NRP topology
   generation method, and the specific control plane and data plane
   mechanisms of an NRP.  And also, the traffic steering policy of the
   NRP may include a dynamic color based policies or an ACL-based static
   ones.

   The NRP partition type is used to describe multiple NRP resource
   partition methods, for example, no partition, control plane resource
   partition, data plane resource partition, or a combination of two
   types.

   As an NRP may consist of the entire or a subset of links in the
   underlay network, there are various methods to generate NRP topology,
   which include:

      The NRP with a subset of links in the underlay network, which has




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      the same topology as the pre-built L3 topology, MT topology,
      flexalgo, or TE topology, and also has the same resource
      reservation requirements.  The topology definition may come
      directly from the topology defined by "control plane".

      For other NRPs that require a dedicated topology, "nrp-topology-
      group" is used to configure the selected links from the base
      topology.  Generally, the base topology refers to the underlay
      network topology.  An NRP can be configured with one or more "nrp-
      topology-group" to create topology resources required by the NRP.
      For example, if an NRP needs to reserve the same bandwidth for a
      groups of links, the same "group-id" can be assigned to the links
      and "bandwidth-reservation" is specified, such as access network
      link group, aggregation network link group, etc.  If some inter-
      domain links, have multiple bandwidth reservation requirements,
      they can also be classified into a group.  Then, each link can
      override the bandwidth reservation of the group bandwidth
      reservation.

   As discussed in [I-D.ietf-teas-nrp-scalability], an NRP could have
   multiple control plane implementation options.  For a better network
   scalability, an NRP does not require an independent distributed
   control protocol instance or a independent centralized control plane
   instance, that is, multiple NRPs can share a same control plane
   instance.  Thus, an NRP can use a predefined native or abstract TE
   topology by referring to a TE network instance or a predefined
   control protocol instance by referring to Layer3 network instance.

   In addition to global NRP parameters, each NRP instance also consists
   of a set of nodes and a set of links, which have different attributes
   that represent the allocated resources or the operational status of
   the NRP.  An NRP could support several data plane resource partition
   methods, which are defined by 'link-partition-type'' under an NRP
   link, which can further be supported by FlexE or independent queue
   techniques.

   There are multiple modes of NRP operations to be supported as
   follows:

   *  NRP instantiation: Depending on the slice services types and also
      network status, there can be two types of approaches.  One method
      is to create an NRP instance before the network controller
      processes the IETF Network Slice service request.  Another one is
      that the network controller may start creating an NRP instance
      while configuring the IETF Network Slice service request.






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   *  NRP modification: When the capacity of an existing NPR link is
      close to capacity, the bandwidth of the link could be increased.
      And when the NRP link or node resources are insufficient, new NRP
      links and nodes could be added.

   *  NRP Deletion: If the NSC determines that no slice service is using
      an NRP, the NSC can delete the NRP instance.

   *  NRP Monitoring: The NSC can use the NRP model to track and monitor
      NRP resource status and usage.

5.  Description of NRP YANG Module

   The description of the NRP data nodes are as follows:

   *  "nrp-id": Is an identifier that is used to uniquely identify an
      NRP instance within the network scope.

   *  NRP partition type: Refers to control plane resource partition,
      data plane resource partition, or a combination of two types.

   *  NRP resources reservation: The nodes and links represent the
      network resource allocated for an NRP instance.  'bandwidth-
      reservation' specifies the bandwidth allocated to an NRP instance,
      or is overridden by the configuration of the NRP link.  'link-
      partition-type' specifies the resource partition types of the
      physical interfaces associated with an NRP link.

   *  NRP control plane: An NRP can use Multi-Topology Routing (MTR) or
      Flex-algo to refer to the IGP instance to generate its own NRP-
      specific forwarding tables.  Multi-Topology Routing (MTR) is
      defined in [RFC4915], [RFC5120], and [I-D.ietf-lsr-isis-sr-vtn-mt]
      or Flex-algo is defined in [I-D.ietf-lsr-flex-algo].

   *  NRP data plane: Defines the data plane mechanism and the NRP
      identifier of the network domain managed by the network
      controller.  The data plane mechanism could be based on MPLS or
      IPv6 forwarding.  The container "data plane" is used to specify
      the NRP data plane encapsulation types and values that are used to
      identify NRP-specific network resources.  The NRP data plane
      identifier is defined, e.g., in
      [I-D.ietf-spring-sr-for-enhanced-vpn]
      and[I-D.dong-6man-enhanced-vpn-vtn-id].

   *  NRP steering policy: The leaf-list "color-id" is used for dynamic
      traffic steering based on SR policy of an NRP and The leaf-list
      "acl-ref" is used for common traffic steering.




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   *  NRP topology group: The list "nrp-topology-group" is used to
      explicitly select subset of links of a underlay topology.

6.  NRP YANG Module Tree

   module: ietf-nrp
     augment /nw:networks/nw:network/nw:network-types:
       +--rw nrp!
     augment /nw:networks/nw:network:
       +--rw nrp
          +--rw nrp-id?                 uint32
          +--rw nrp-name?               string
          +--rw partition-type?         identityref
          +--rw resource-reservation
          |  +--rw link-partition-type?     identityref
          |  +--rw bandwidth-reservation
          |     +--rw (bandwidth-type)?
          |        +--:(bandwidth-value)
          |        |  +--rw bandwidth-value?     uint64
          |        +--:(bandwidth-percentage)
          |           +--rw bandwidth-percent?   rt-types:percentage
          +--rw control-plane
          |  +--rw multi-topology-id?            uint32
          |  +--rw algo-id?                      uint32
          |  +--rw sharing?                      boolean
          |  +--rw topology-change-is-allowed?   boolean
          +--rw data-plane
          |  +--rw global-resource-identifier
          |  |  +--rw ipv6
          |  |  |  +--rw value?   inet:ipv6-address
          |  |  +--rw mpls
          |  |     +--rw label?   uint32
          |  +--rw nrp-aware
          |     +--rw srv6!
          |     +--rw sr-mpls!
          +--rw steering-policy
          |  +--rw color-id*   uint32
          |  +--rw acl-ref*    -> /acl:acls/acl/name
          +--rw topology-group* [group-id]
             +--rw group-id                string
             +--rw base-topology-ref
             |  +--rw network-ref?
             |          -> /nw:networks/network/network-id
             +--rw links* [link-ref]
             |  +--rw link-ref    leafref
             +--rw resource-reservation
                +--rw link-partition-type?     identityref
                +--rw bandwidth-reservation



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                   +--rw (bandwidth-type)?
                      +--:(bandwidth-value)
                      |  +--rw bandwidth-value?     uint64
                      +--:(bandwidth-percentage)
                         +--rw bandwidth-percent?
                                 rt-types:percentage
     augment /nw:networks/nw:network/nw:node:
       +--ro nrp
          +--ro data-plane-id
             +--ro ipv6?      srv6-sid
             +--ro sr-mpls?   rt-types:mpls-label
     augment /nw:networks/nw:network/nt:link:
       +--rw nrp
          +--rw bandwidth-value?       uint64
          +--ro link-partition-type?   identityref
          +--ro data-plane-id
          |  +--ro ipv6?      srv6-sid
          |  +--ro sr-mpls?   rt-types:mpls-label
          +--ro statistics
             +--ro admin-status?
             |       te-types:te-admin-status
             +--ro oper-status?
             |       te-types:te-oper-status
             +--ro one-way-available-bandwidth?
             |       rt-types:bandwidth-ieee-float32
             +--ro one-way-utilized-bandwidth?
             |       rt-types:bandwidth-ieee-float32
             +--ro one-way-min-delay?             uint32
             +--ro one-way-max-delay?             uint32
             +--ro one-way-delay-variation?       uint32
             +--ro one-way-packet-loss?           decimal64
     augment /nw:networks/nw:network/nw:node:
       +--rw nrps* [nrp-id]
          +--rw nrp-id    uint32
          +--ro nrp
             +--ro data-plane-id
                +--ro ipv6?      srv6-sid
                +--ro sr-mpls?   rt-types:mpls-label
     augment /nw:networks/nw:network/nt:link:
       +--rw nrps* [nrp-id]
          +--rw nrp-id                 uint32
          +--ro link-partition-type?   identityref
          +--ro data-plane-id
          |  +--ro ipv6?      srv6-sid
          |  +--ro sr-mpls?   rt-types:mpls-label
          +--ro statistics
             +--ro admin-status?
             |       te-types:te-admin-status



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             +--ro oper-status?
             |       te-types:te-oper-status
             +--ro one-way-available-bandwidth?
             |       rt-types:bandwidth-ieee-float32
             +--ro one-way-utilized-bandwidth?
             |       rt-types:bandwidth-ieee-float32
             +--ro one-way-min-delay?             uint32
             +--ro one-way-max-delay?             uint32
             +--ro one-way-delay-variation?       uint32
             +--ro one-way-packet-loss?           decimal64

7.  NRP Yang Module

   <CODE BEGINS> file "ietf-nrp@2022-09-26.yang"

module ietf-nrp {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-nrp";
  prefix nrp;

  import ietf-network {
    prefix nw;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies";
  }
  import ietf-network-topology {
    prefix nt;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies";
  }
  import ietf-routing-types {
    prefix rt-types;
    reference
      "RFC 8294: Common YANG Data Types for the Routing Area";
  }
  import ietf-te-types {
    prefix te-types;
    reference
      "RFC 8776: Traffic Engineering Common YANG Types";
  }
  import ietf-te-packet-types {
    prefix te-packet-types;
    reference
      "RFC 8776: Traffic Engineering Common YANG Types";
  }
  import ietf-inet-types {
    prefix inet;
    reference



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      "RFC 6991: Common YANG Data Types";
  }
  import ietf-access-control-list {
    prefix acl;
    reference
      "RFC 8519: YANG Data Model for Network Access Control Lists
       (ACLs)";
  }

  organization
    "IETF TEAS Working Group";
  contact
    "
     WG Web: <http://tools.ietf.org/wg/teas/>
     WG List:<mailto:teas@ietf.org>

     Editor: Bo Wu <lana.wubo@huawei.com>
           : Dhruv Dhody <dhruv.ietf@gmail.com>";
  description
    "This YANG module defines a network data module for
     NRP(Network Resource Partition).

     Copyright (c) 2022 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Revised BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC XXXX
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
     for full legal notices.";

  revision 2022-09-26 {
    description
      "This is the initial version of NRP YANG model.";
    reference
      "RFC XXX: A YANG Data Model for Network Resource Partition";
  }

  typedef srv6-sid {
    type inet:ipv6-prefix;
    description
      "Defines an SRv6 Segment ID (SID). That is,
       an IPv6 address explicitly associated with the segment.";



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    reference
      "RFC 8402: Segment Routing Architecture";
  }

  identity nrp-partition-type {
    description
      "Base identity for nrp partition type.";
  }

  identity nrp-control-plane-partition {
    base nrp-partition-type;
    description
      "Identity for control plane partition.";
  }

  identity nrp-data-plane-partition {
    base nrp-partition-type;
    description
      "Identity for data plane partition.";
  }

  identity nrp-hybrid-plane-partition {
    base nrp-partition-type;
    description
      "Identity for both planes partition.";
  }

  identity nrp-link-partition-type {
    description
      "Base identity for interface partition type.";
  }

  identity virtual-sub-interface-partition {
    base nrp-link-partition-type;
    description
      "Identity for virtual interface or sub-interface, e.g. FlexE.";
  }

  identity queue-partition {
    base nrp-link-partition-type;
    description
      "Identity for queue partition type.";
  }

  /*
   * Groupings
   */




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  grouping nrp-resource-reservation {
    description
      "Grouping for NRP resource reservation.";
    container resource-reservation {
      description
        "Container for NRP resource reservation.";
      leaf link-partition-type {
        type identityref {
          base nrp-link-partition-type;
        }
        description
          "Indicates the resource reservation type of an NRP link.";
      }
      container bandwidth-reservation {
        description
          "Container for NRP bandwidth reservation.";
        choice bandwidth-type {
          description
            "Choice of bandwidth reservation type.";
          case bandwidth-value {
            leaf bandwidth-value {
              type uint64;
              units "bps";
              description
                "Bandwidth allocation for the NRP as absolute value.";
            }
          }
          case bandwidth-percentage {
            leaf bandwidth-percent {
              type rt-types:percentage;
              description
                "Bandwidth allocation for the NRP as a percentage
                 of a link.";
            }
          }
        }
      }
    }
  }

  grouping nrp-control-plane-attributes {
    description
      "Grouping for NRP control plane attributes.";
    container control-plane {
      description
        "The container of NRP control plane mechanisms.";
      leaf multi-topology-id {
        type uint32;



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        description
          "Indicates the MT-id of the NRP distributed control plane.";
      }
      leaf algo-id {
        type uint32;
        description
          "Indicates the algo-id of the NRP distributed control plane.";
      }
      leaf sharing {
        type boolean;
        default "true";
        description
          "'true' if the the NRP distributed control plane
           can be shared with other NRPs;
           'false' if the the NRP distributed control plane
           is dedicated to this NRP.";
      }
      leaf topology-change-is-allowed {
        type boolean;
        description
          "true  - topology change is allowed,
           false - topology change is disallowed.";
      }
    }
  }

  grouping nrp-data-plane-attributes {
    description
      "Grouping for NRP data plane attributes.";
    container data-plane {
      description
        "The data plane mechanisms of an NRP. The forwarding plane
         could be MPLS, IPv6, SRv6, or SR-MPLS.";
      container global-resource-identifier {
        description
          "The container of global NRP data-plane ID.";
        container ipv6 {
          description
            "The container of IPv6 based NRP data-plane identifier.";
          leaf value {
            type inet:ipv6-address;
            description
              "Indicates the IPv6 NRP data-plane identifier.";
          }
        }
        container mpls {
          description
            "The container of MPLS based NRP data-plane identifier.";



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          leaf label {
            type uint32;
            description
              "Indicates MPLS metadata values to identify MPLS NRP
               data plane identifier, e.g. Ancillary data.";
          }
        }
      }
      container nrp-aware {
        description
          "The container of SR based NRP data-plane identifier.";
        container srv6 {
          presence "Enables SRv6 data plane type.";
          description
            "The container of SRv6 based NRP data-plane identifier.";
        }
        container sr-mpls {
          presence "Enables SR MPLS data plane type.";
          description
            "The container of SR MPLS based NRP data-plane identifier.";
        }
      }
    }
  }

  grouping nrp-traffic-steering-policy {
    description
      "The grouping of the NRP traffic steering policy.";
    container steering-policy {
      description
        "The container of a policy set
         matching an NRP traffic classifier.";
      leaf-list color-id {
        type uint32;
        description
          "A list of color ID for NRP traffic steering based on
           SR policy.";
      }
      leaf-list acl-ref {
        type leafref {
          path "/acl:acls/acl:acl/acl:name";
        }
        description
          "A list of ACL for NRP traffic classification.";
      }
    }
  }




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  grouping nrp-aware-id {
    description
      "The grouping of NRP aware dataplane ID.";
    container data-plane-id {
      config false;
      description
        "The container of NRP data plane identifier.";
      leaf ipv6 {
        type srv6-sid;
        description
          "Indicates the SRv6 SID value as the NRP data plane
           identifier.";
      }
      leaf sr-mpls {
        type rt-types:mpls-label;
        description
          "Indicates the SR MPLS ID value as the NRP data plane
           identifier.";
      }
    }
  }

  grouping nrp-topology {
    description
      "Grouping for NRP topology.";
    list topology-group {
      key "group-id";
      description
        "List of groups for NRP topology elements (node or links)
         that share common attributes.";
      leaf group-id {
        type string;
        description
          "The NRP topology group identifier.";
      }
      container base-topology-ref {
        description
          "Container for the base topology reference.";
        uses nw:network-ref;
      }
      list links {
        key "link-ref";
        description
          "A list of links with common attributes";
        leaf link-ref {
          type leafref {
            path
              "/nw:networks/nw:network[nw:network-id=current()"



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            + "/../../base-topology-ref/network-ref]"
            + "/nt:link/nt:link-id";
          }
          description
            "A reference to a link in the base topology.";
        }
      }
      uses nrp-resource-reservation;
    }
  }

  grouping nrp-topology-attributes {
    description
      "NRP global attributes.";
    container nrp {
      description
        "Containing NRP topology attributes.";
      leaf nrp-id {
        type uint32;
        description
          "NRP identifier.";
      }
      leaf nrp-name {
        type string;
        description
          "NRP Name.";
      }
      leaf partition-type {
        type identityref {
          base nrp-partition-type;
        }
        description
          "Indicates the resource partition type of the NRP, such as
           control plane partition, data plane partition,
           or no partition.";
      }
      uses nrp-resource-reservation;
      uses nrp-control-plane-attributes;
      uses nrp-data-plane-attributes;
      uses nrp-traffic-steering-policy;
      uses nrp-topology;
    }
    // nrp
  }

  // nrp-node-attributes

  grouping nrp-node-attributes {



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    description
      "NRP node scope attributes.";
    container nrp {
      config false;
      description
        "Containing NRP attributes.";
      uses nrp-aware-id;
    }
  }

  // nrp-node-attributes

  grouping nrp-link-states {
    description
      "NRP link scope states.";
    leaf link-partition-type {
      type identityref {
        base nrp-link-partition-type;
      }
      config false;
      description
        "Indicates the resource partition type of an NRP link.";
    }
    uses nrp-aware-id;
    uses nrp-statistics-per-link;
  }

  // one-way-performance-metrics

  grouping one-way-performance-bandwidth {
    description
      "Grouping for one-way performance bandwidth.";
    leaf one-way-available-bandwidth {
      type rt-types:bandwidth-ieee-float32;
      units "bytes per second";
      default "0x0p0";
      description
        "Available bandwidth that is defined to be NRP link
         bandwidth minus bandwidth utilization. For a
         bundled link, available bandwidth is defined to be the
         sum of the component link available bandwidths.";
    }
    leaf one-way-utilized-bandwidth {
      type rt-types:bandwidth-ieee-float32;
      units "bytes per second";
      default "0x0p0";
      description
        "Bandwidth utilization that represents the actual



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         utilization of the link (i.e. as measured in the router).
         For a bundled link, bandwidth utilization is defined to
         be the sum of the component link bandwidth
         utilizations.";
    }
  }

  // nrp-link-statistics

  grouping nrp-statistics-per-link {
    description
      "Statistics attributes per NRP link.";
    container statistics {
      config false;
      description
        "Statistics for NRP link.";
      leaf admin-status {
        type te-types:te-admin-status;
        description
          "The administrative state of the link.";
      }
      leaf oper-status {
        type te-types:te-oper-status;
        description
          "The current operational state of the link.";
      }
      uses one-way-performance-bandwidth;
      uses te-packet-types:one-way-performance-metrics-packet;
    }
  }

  grouping nrp-augment {
    description
      "Augmentation for NRPs.";
    container nrp {
      presence "NRP support";
      description
        "Indicates NRP support.";
    }
    // nrp
  }

  // nrp-augment

  augment "/nw:networks/nw:network/nw:network-types" {
    description
      "Defines the NRP topology type.";
    container nrp {



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      presence "Indicates NRP topology";
      description
        "The presence identifies the NRP type.";
    }
  }

  augment "/nw:networks/nw:network" {
    when 'nw:network-types/nrp:nrp' {
      description
        "Augment only for NRP topology.";
    }
    description
      "Augment NRP configuration and state.";
    uses nrp-topology-attributes;
  }

  augment "/nw:networks/nw:network/nw:node" {
    when '../nw:network-types/nrp:nrp' {
      description
        "Augment only for NRP topology.";
    }
    description
      "Augment node configuration and state.";
    uses nrp-node-attributes;
  }

  augment "/nw:networks/nw:network/nt:link" {
    when '../nw:network-types/nrp:nrp' {
      description
        "Augment only for NRP topology.";
    }
    description
      "Augment link configuration and state.";
    container nrp {
      description
        "Containing NRP attributes.";
      leaf bandwidth-value {
        type uint64;
        units "bps";
        description
          "Bandwidth allocation for the NRP as absolute value.";
      }
      uses nrp-link-states;
    }
  }

  augment "/nw:networks/nw:network/nw:node" {
    description



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      "Augment node with NRP aware attributes.";
    list nrps {
      key "nrp-id";
      description
        "List of NRPs.";
      leaf nrp-id {
        type uint32;
        description
          "NRP identifier";
      }
      uses nrp-node-attributes;
    }
  }

  augment "/nw:networks/nw:network/nt:link" {
    description
      "Augment link with NRP aware attributes.";
    list nrps {
      key "nrp-id";
      description
        "List of NRPs.";
      leaf nrp-id {
        type uint32;
        description
          "NRP identifier";
      }
      uses nrp-link-states;
    }
  }
}

   <CODE ENDS>

8.  Security Considerations

   The YANG model defined in this document is designed to be accessed
   via network management protocols such as NETCONF [RFC6241] or
   RESTCONF [RFC8040].  The lowest NETCONF layer is the secure transport
   layer, and the mandatory-to-implement secure transport is Secure
   Shell (SSH) [RFC6242].  The lowest RESTCONF layer is HTTPS, and the
   mandatory-to-implement secure transport is TLS [RFC8446].

   The NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.





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   There are a number of data nodes defined in this YANG model that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.

   nrp-link: A malicious client could attempt to remove a link from a
   topology, add a new link.  In each case, the structure of the
   topology would be sabotaged, and this scenario could, for example,
   result in an NRP topology that is less than optimal.

   The entries in the nodes above include the whole network
   configurations corresponding with the NRP, and indirectly create or
   modify the PE or P device configurations.  Unexpected changes to
   these entries could lead to service disruption and/or network
   misbehavior.

9.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in [RFC3688], the following registration is
   requested to be made:

      URI: urn:ietf:params:xml:ns:yang:ietf-nrp
      Registrant Contact: The IESG.
      XML: N/A, the requested URI is an XML namespace.

   This document requests to register a YANG module in the YANG Module
   Names registry [RFC7950].

              Name: ietf-nrp
              Namespace: urn:ietf:params:xml:ns:yang:ietf-nrp
              Prefix: nrp
              Reference: RFC XXXX

10.  Contributor

      Zhenbin Li
      Huawei

      Email: lizhenbin@huawei.com


      Jie Dong
      Huawei

      Email: jie.dong@huawei.com



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11.  References

11.1.  Normative References

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC4915]  Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
              Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
              RFC 4915, DOI 10.17487/RFC4915, June 2007,
              <https://www.rfc-editor.org/info/rfc4915>.

   [RFC5120]  Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
              Topology (MT) Routing in Intermediate System to
              Intermediate Systems (IS-ISs)", RFC 5120,
              DOI 10.17487/RFC5120, February 2008,
              <https://www.rfc-editor.org/info/rfc5120>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.



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   [RFC8345]  Clemm, A., Medved, J., Varga, R., Bahadur, N.,
              Ananthakrishnan, H., and X. Liu, "A YANG Data Model for
              Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March
              2018, <https://www.rfc-editor.org/info/rfc8345>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

11.2.  Informative References

   [I-D.dong-6man-enhanced-vpn-vtn-id]
              Dong, J., Li, Z., Xie, C., Ma, C., and G. Mishra,
              "Carrying Virtual Transport Network (VTN) Identifier in
              IPv6 Extension Header", Work in Progress, Internet-Draft,
              draft-dong-6man-enhanced-vpn-vtn-id-06, 24 October 2021,
              <https://www.ietf.org/archive/id/draft-dong-6man-enhanced-
              vpn-vtn-id-06.txt>.

   [I-D.dong-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-dong-idr-sr-policy-nrp-01, 11 July
              2022, <https://www.ietf.org/archive/id/draft-dong-idr-sr-
              policy-nrp-01.txt>.

   [I-D.ietf-lsr-flex-algo]
              Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
              A. Gulko, "IGP Flexible Algorithm", Work in Progress,
              Internet-Draft, draft-ietf-lsr-flex-algo-23, 19 September
              2022, <https://www.ietf.org/archive/id/draft-ietf-lsr-
              flex-algo-23.txt>.

   [I-D.ietf-lsr-isis-sr-vtn-mt]
              Xie, C., Ma, C., Dong, J., and Z. Li, "Using IS-IS Multi-
              Topology (MT) for Segment Routing based Virtual Transport
              Network", Work in Progress, Internet-Draft, draft-ietf-
              lsr-isis-sr-vtn-mt-03, 10 July 2022,
              <https://www.ietf.org/archive/id/draft-ietf-lsr-isis-sr-
              vtn-mt-03.txt>.

   [I-D.ietf-spring-sr-for-enhanced-vpn]
              Dong, J., Bryant, S., Miyasaka, T., Zhu, Y., Qin, F., Li,
              Z., and F. Clad, "Segment Routing based Virtual Transport
              Network (VTN) for Enhanced VPN", Work in Progress,
              Internet-Draft, draft-ietf-spring-sr-for-enhanced-vpn-03,
              8 September 2022, <https://www.ietf.org/archive/id/draft-
              ietf-spring-sr-for-enhanced-vpn-03.txt>.



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   [I-D.ietf-teas-ietf-network-slices]
              Farrel, A., Drake, J., Rokui, R., Homma, S., Makhijani,
              K., Contreras, L. M., and J. Tantsura, "Framework for IETF
              Network Slices", Work in Progress, Internet-Draft, draft-
              ietf-teas-ietf-network-slices-14, 3 August 2022,
              <https://www.ietf.org/archive/id/draft-ietf-teas-ietf-
              network-slices-14.txt>.

   [I-D.ietf-teas-nrp-scalability]
              Dong, J., Li, Z., Gong, L., Yang, G., Guichard, J. N.,
              Mishra, G., Qin, F., Saad, T., and V. P. Beeram,
              "Scalability Considerations for Network Resource
              Partition", Work in Progress, Internet-Draft, draft-ietf-
              teas-nrp-scalability-00, 11 July 2022,
              <https://www.ietf.org/archive/id/draft-ietf-teas-nrp-
              scalability-00.txt>.

   [I-D.ietf-teas-ns-ip-mpls]
              Saad, T., Beeram, V. P., Dong, J., Wen, B., Ceccarelli,
              D., Halpern, J., Peng, S., Chen, R., Liu, X., Contreras,
              L. M., Rokui, R., and L. Jalil, "Realizing Network Slices
              in IP/MPLS Networks", Work in Progress, Internet-Draft,
              draft-ietf-teas-ns-ip-mpls-00, 16 June 2022,
              <https://www.ietf.org/archive/id/draft-ietf-teas-ns-ip-
              mpls-00.txt>.

   [RFC8309]  Wu, Q., Liu, W., and A. Farrel, "Service Models
              Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
              <https://www.rfc-editor.org/info/rfc8309>.

   [RFC9182]  Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M.,
              Ed., Munoz, L., and A. Aguado, "A YANG Network Data Model
              for Layer 3 VPNs", RFC 9182, DOI 10.17487/RFC9182,
              February 2022, <https://www.rfc-editor.org/info/rfc9182>.

   [RFC9291]  Boucadair, M., Ed., Gonzalez de Dios, O., Ed., Barguil,
              S., and L. Munoz, "A YANG Network Data Model for Layer 2
              VPNs", RFC 9291, DOI 10.17487/RFC9291, September 2022,
              <https://www.rfc-editor.org/info/rfc9291>.

Appendix A.  An Example

   This section contains an example of an instance data tree in JSON
   encoding [RFC7951].  The example instantiates ietf-nrp for the
   topology that is depicted in the following diagram.  There are three
   nodes, D1, D2, and D3.  D1 has three termination points, 1-0-1,
   1-2-1, and 1-3-1.  D2 has three termination points as well, 2-1-1,
   2-0-1, and 2-3-1.  D3 has two termination points, 3-1-1 and 3-2-1.



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   In addition there are six links, two between each pair of nodes with
   one going in each direction.



                +------------+                   +------------+
                |     D1     |                   |     D2     |
               /-\          /-\                 /-\          /-\
               | | 1-0-1    | |---------------->| | 2-1-1    | |
               | |    1-2-1 | |<----------------| |    2-0-1 | |
               \-/  1-3-1   \-/                 \-/  2-3-1   \-/
                |   /----\   |                   |   /----\   |
                +---|    |---+                   +---|    |---+
                    \----/                           \----/
                     |  |                             |  |
                     |  |                             |  |
                     |  |                             |  |
                     |  |       +------------+        |  |
                     |  |       |     D3     |        |  |
                     |  |      /-\          /-\       |  |
                     |  +----->| | 3-1-1    | |-------+  |
                     +---------| |    3-2-1 | |<---------+
                               \-/          \-/
                                |            |
                                +------------+

                     Figure 4: An NRP Instance Example

   The corresponding NRP instance data tree is depicted below:

   {
     "ietf-network:networks": {
       "network": [
         {
           "network-types": {
             "ietf-nrp:nrp": {}
           },
           "network-id": "foo:nrp-example",
           "ietf-nrp:nrp": {
             "nrp-id": "1",
             "nrp-name": "NRP1",
             "partition-type": "nrp-hybrid-plane-partition",
             "resource-reservation": {
               "link-partition-type": "virtual-sub-interface-partition",
               "bandwidth-reservation": {
                 "bandwidth-value": "10000"
               }
             },



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             "control-plane": {
               "distributed-control": {}
             },
             "data-plane": {
               "global-resource-identifier": {
                 "nrp-dataplane-ipv6-type": {
                   " nrp-dp-value:": "100"
                 }
               }
             },
             "steering-policy": {
               "color-id": "100"
             },
             "nrp-topology-group": [
               {
                 "group-id": "access-group",
                 "base-topology-ref": {
                   "network-ref": "native-topology"
                 },
                 "link": [
                   {
                     "link-ref": "D1,1-2-1,D2,2-1-1"
                   },
                   {
                     "link-ref": "D2,2-1-1,D1,1-2-1"
                   },
                   {
                     "link-ref": "D1,1-3-1,D3,3-1-1"
                   },
                   {
                     "link-ref": "D3,3-1-1,D1,1-3-1"
                   },
                   {
                     "link-ref": "D2,2-3-1,D3,3-2-1"
                   },
                   {
                     "link-ref": "D3,3-2-1,D2,2-3-1"
                   }
                 ]
               }
             ]
           }
         }
       ]
     }
   }

                        Figure 5: Instance data tree



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Authors' Addresses

   Bo Wu
   Huawei Technologies
   101 Software Avenue, Yuhua District
   Nanjing
   Jiangsu, 210012
   China
   Email: lana.wubo@huawei.com


   Dhruv Dhody
   Huawei Technologies
   Divyashree Techno Park
   Bangalore 560066
   Karnataka
   India
   Email: dhruv.ietf@gmail.com


   Mohamed Boucadair
   Orange
   Rennes 35000
   France
   Email: mohamed.boucadair@orange.com


   Ying Cheng
   China Unicom
   Beijing
   China
   Email: chengying10@chinaunicom.cn


   Liyan Gong
   China Mobile
   Beijing
   China
   Email: gongliyan@chinamobile.com












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