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Versions: (draft-majumdar-idr-bgp-srte-yang) 00

Inter-Domain Routing Working Group                              K. Deevi
Internet-Draft                                                   K. Raza
Intended status: Standards Track                                   Cisco
Expires: January 8, 2021                                     K. Majumdar
                                                               Commscope
                                                             B. Decraene
                                                                  Orange
                                                                Z. Jiang
                                                                 Tencent
                                                      September 27, 2020


         YANG data model for BGP Segment Routing TE Extensions
                    draft-deevi-idr-bgp-srte-yang-00

Abstract

   This document defines a YANG data model that can be used to configure
   and manage Segment Routing TE extensions in BGP.

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 January 8, 2021.

Copyright Notice

   Copyright (c) 2020 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



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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
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   Without obtaining an adequate license from the person(s) controlling
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   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  BGP Segment Routing Traffic Engineering Yang model  . . . . .   3
     2.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  SR Policy . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  Automatic Steering  . . . . . . . . . . . . . . . . . . .   4
   3.  Yang Tree . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  SR Policy . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Automatic Steering  . . . . . . . . . . . . . . . . . . .   8
   4.  Yang Module . . . . . . . . . . . . . . . . . . . . . . . . .   9
   5.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  25
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  26
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  26
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  26
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  26
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  26
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  27
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  28

1.  Introduction

   YANG [RFC6020] is a data definition language that was introduced to
   define the contents of a conceptual data store that allows networked
   devices to be managed using NETCONF [RFC6241].  YANG is proving
   relevant beyond its initial confines, as bindings to other interfaces
   (e.g.  ReST) [RFC8040] and encodings other than XML (e.g.  JSON)
   [RFC7951] are being defined.  Furthermore, YANG data models can be
   used as the basis of implementation for other interfaces, such as CLI
   and programmatic APIs.




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   This document defines the YANG model for Segment Routing TE specific
   extensions in BGP.

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.  BGP Segment Routing Traffic Engineering Yang model

2.1.  Overview

   Segment Routing (SR), as defined in [RFC8402], leverages the source
   routing paradigm where a node steers a packet through an ordered list
   of instructions, called segments.  SR, thus, allows enforcing a flow
   through any topological path and/or service chain while maintaining
   per-flow state only at the ingress nodes to the SR domain.

   When applied to ipv6 data-plane (i.e.  SRv6), the ordered set of
   instructions are realized via SRv6 SIDs.  The various functions and
   behaviors corresponding to network programming using SRv6 are
   specified in [I-D.ietf-spring-srv6-network-programming].

   This document defines Yang model for the Segment Routing TE
   extensions applicable for BGP as following:

   o  BGP signaled SR Policy as described in
      [I-D.ietf-idr-segment-routing-te-policy].

   o  Automatic Steering as described in
      [I-D.ietf-spring-segment-routing-policy] and
      [I-D.ietf-idr-segment-routing-te-policy].

   The Yang extensions proposed in this model augment the base BGP model
   defined in [I-D.ietf-idr-bgp-model].

   Note: Base BGP model does not have a common structure for BGP RIB.
   The placeholder containers defined in this model can be removed once
   base BGP model has the BGP RIB structure.

   The modeling in this document complies with the Network Management
   Datastore Architecture (NMDA) [RFC8342].  The operational state data
   is combined with the associated configuration data in the same
   hierarchy [RFC8407].  When protocol states are retrieved from the
   NMDA operational state datastore, the returned states cover all



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   "config true" (rw) and "config false" (ro) nodes defined in the
   schema.

2.2.  SR Policy

   Architecture for SR Policies is described in
   [I-D.ietf-spring-segment-routing-policy].  BGP Signaled SR Policies
   are described in the [I-D.ietf-idr-segment-routing-te-policy].
   Following Yang extensions for SR Policy configuration and state data
   are applicable:

   o  Addition of identies extending the BGP-AFI-SAFI base identity.
      This is to add two new address families namely IPv4 SR-policy and
      IPv6 SR-policy, as described in
      [I-D.ietf-idr-segment-routing-te-policy].

   o  BGP Signaled SR Policy candidate paths.  These refer to the
      explicit candidate paths signaled via BGP as SAFI NLRIs, state of
      which is applicable in the context of BGP speaker process.  This
      is modeled by adding SR Policy address family specific container
      under generic BGP afi-safi list entry defined in the base BGP
      model [I-D.ietf-idr-bgp-model].

   o  On Demand SR Policy candidate paths.  These refer to the dynamic
      candidate paths as described in
      [I-D.ietf-spring-segment-routing-policy].  There are two parts to
      this in the context of BGP.  A set of authorized SR Policy colors
      for on demand policy triggers, and the actual instantiated
      candidate paths per BGP next-hop.  New containers and lists are
      added under BGP global mode to model this information.

   o  SR Policy state in the context of BGP speaker.  This represents
      the state SR Policies (regardless of method of instantiation per
      candidate path).  The SR Policy state is maintained in the context
      of BGP speaker process to realize the Automatic Steering of
      overlay routes.  Automatic Steering extensions are described in
      the next section.

   Note: The common parameters and datatypes for the SR Policy,
   currently defined in this model, should be imported from SR Policy
   Manager model, once available.

2.3.  Automatic Steering

   Automatic Steering (AS) refers to the ability to forward traffic over
   a SR Policy on the head-end, as described in
   [I-D.ietf-spring-segment-routing-policy].  When a BGP route is
   received with the color extended community and if the color value



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   matches the color of an authorized SR Policy installed on the head-
   end, the route is programmed to resolve over SR Policy in forwarding.
   Automatic Steering information associated with the BGP routes is
   modeled as state information per route.

   TBD: The configuration parameters for Automatic Steering are yet to
   be added as an augmentation to the BGP route policy model.  Such as,
   extensions for opaque color extended community in BGP policy model,
   and the Color Only (CO) flags controlling the Automatic Steering
   behavior as described in [I-D.ietf-idr-segment-routing-te-policy].

3.  Yang Tree

3.1.  SR Policy

   On Demand Nexthop (ODN) policies triggered by BGP

   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global:
   +--rw segment-routing
      +--rw on-demand-policies
      |  +--ro authorized-colors
      |  |  +--ro colors* [color]
      |  |     +--ro color    uint32
      |  +--ro installed-policies
      |     +--ro sr-policy* [color end-point]
      |        +--ro color        uint32
      |        +--ro end-point    inet:ip-address
      +--ro policy-state
         +--ro sr-policy* [color end-point]
            +--ro color                uint32
            +--ro end-point            inet:ip-address
            +--ro policy-state?        enumeration
            +--ro binding-sid?         sid-type
            +--ro steering-disabled?   empty
            +--ro ref-count?           uint32

   BGP Signaled Explicit SR Policies under ipv4 and ipv6 SR-Policy SAFI

   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi:
   +--rw ipv4-srpolicy
      +--ro explicit-policies
         +--ro sr-policy* [distinguisher color end-point]
            +--ro distinguisher           uint32
            +--ro color                   uint32
            +--ro end-point               inet:ip-address
            +--ro preference?             uint32
            +--ro explicit-binding-sid
            |  +--ro binding-sid?       sid-type



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            |  +--ro strict?            boolean
            |  +--ro drop-on-invalid?   boolean
            +--ro usable?                 boolean
            +--ro registered?             boolean
            +--ro segment-lists
               +--ro segment-list* [weight]
                  +--ro weight      uint32
                  +--ro segments
                     +--ro segment* [index]
                        +--ro index            uint32
                        +--ro type?            segment-type
                        +--ro segment-types
                           +--ro segment-type-1
                           |  +--ro sid-value?   rt-types:mpls-label
                           +--ro segment-type-2
                           |  +--ro sid-value?   srv6-types:srv6-sid
                           +--ro segment-type-3
                           |  +--ro ipv4-address?   inet:ipv4-address
                           |  +--ro algorithm?      uint8
                           +--ro segment-type-4
                           |  +--ro ipv6-address?   inet:ipv6-address
                           |  +--ro algorithm?      uint8
                           +--ro segment-type-5
                           |  +--ro ipv4-address?           inet:ipv4-address
                           |  +--ro interface-identifier?   uint32
                           +--ro segment-type-6
                           |  +--ro local-ipv4-address?    inet:ipv4-address
                           |  +--ro remote-ipv4-address?   inet:ipv4-address
                           +--ro segment-type-7
                           |  +--ro local-ipv6-address?            inet:ipv6-address
                           |  +--ro local-interface-identifier?    uint32
                           |  +--ro remote-ipv6-address?           inet:ipv6-address
                           |  +--ro remote-interface-identifier?   uint32
                           +--ro segment-type-8
                           |  +--ro local-ipv6-address?    inet:ipv6-address
                           |  +--ro remote-ipv6-address?   inet:ipv6-address
                           +--ro segment-type-9
                           |  +--ro ipv6-address?   inet:ipv6-address
                           |  +--ro algorithm?      uint8
                           +--ro segment-type-10
                           |  +--ro local-ipv6-address?            inet:ipv6-address
                           |  +--ro local-interface-identifier?    uint32
                           |  +--ro remote-ipv6-address?           inet:ipv6-address
                           |  +--ro remote-interface-identifier?   uint32
                           +--ro segment-type-11
                              +--ro local-ipv6-address?    inet:ipv6-address
                              +--ro remote-ipv6-address?   inet:ipv6-address
   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi:



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   +--rw ipv6-srpolicy
      +--ro explicit-policies
         +--ro sr-policy* [distinguisher color end-point]
            +--ro distinguisher           uint32
            +--ro color                   uint32
            +--ro end-point               inet:ip-address
            +--ro preference?             uint32
            +--ro explicit-binding-sid
            |  +--ro binding-sid?       sid-type
            |  +--ro strict?            boolean
            |  +--ro drop-on-invalid?   boolean
            +--ro usable?                 boolean
            +--ro registered?             boolean
            +--ro segment-lists
               +--ro segment-list* [weight]
                  +--ro weight      uint32
                  +--ro segments
                     +--ro segment* [index]
                        +--ro index            uint32
                        +--ro type?            segment-type
                        +--ro segment-types
                           +--ro segment-type-1
                           |  +--ro sid-value?   rt-types:mpls-label
                           +--ro segment-type-2
                           |  +--ro sid-value?   srv6-types:srv6-sid
                           +--ro segment-type-3
                           |  +--ro ipv4-address?   inet:ipv4-address
                           |  +--ro algorithm?      uint8
                           +--ro segment-type-4
                           |  +--ro ipv6-address?   inet:ipv6-address
                           |  +--ro algorithm?      uint8
                           +--ro segment-type-5
                           |  +--ro ipv4-address?           inet:ipv4-address
                           |  +--ro interface-identifier?   uint32
                           +--ro segment-type-6
                           |  +--ro local-ipv4-address?    inet:ipv4-address
                           |  +--ro remote-ipv4-address?   inet:ipv4-address
                           +--ro segment-type-7
                           |  +--ro local-ipv6-address?            inet:ipv6-address
                           |  +--ro local-interface-identifier?    uint32
                           |  +--ro remote-ipv6-address?           inet:ipv6-address
                           |  +--ro remote-interface-identifier?   uint32
                           +--ro segment-type-8
                           |  +--ro local-ipv6-address?    inet:ipv6-address
                           |  +--ro remote-ipv6-address?   inet:ipv6-address
                           +--ro segment-type-9
                           |  +--ro ipv6-address?   inet:ipv6-address
                           |  +--ro algorithm?      uint8



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                           +--ro segment-type-10
                           |  +--ro local-ipv6-address?            inet:ipv6-address
                           |  +--ro local-interface-identifier?    uint32
                           |  +--ro remote-ipv6-address?           inet:ipv6-address
                           |  +--ro remote-interface-identifier?   uint32
                           +--ro segment-type-11
                              +--ro local-ipv6-address?    inet:ipv6-address
                              +--ro remote-ipv6-address?   inet:ipv6-address

3.2.  Automatic Steering

   Yang Tree for Automatic Steering with example of ipv4-unicast SAFI


module: ietf-bgp-srte
   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv4-unicast:
   +--ro routes
      +--ro route* [prefix neighbor add-path-id]
         +--ro prefix                union
         +--ro neighbor              inet:ip-address
         +--ro add-path-id           uint32
         +--ro automatic-steering
            +--ro color?         -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/color
            +--ro end-point?     -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/end-point
            +--ro co-flag?       enumeration
            +--ro binding-sid?   -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/binding-sid
   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv6-unicast:
   +--ro routes
      +--ro route* [prefix neighbor add-path-id]
         +--ro prefix                union
         +--ro neighbor              inet:ip-address
         +--ro add-path-id           uint32
         +--ro automatic-steering
            +--ro color?         -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/color
            +--ro end-point?     -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/end-point
            +--ro co-flag?       enumeration
            +--ro binding-sid?   -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/binding-sid
   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv4-labeled-unicast:
   +--ro routes
      +--ro route* [prefix neighbor add-path-id]
         +--ro prefix                union
         +--ro neighbor              inet:ip-address
         +--ro add-path-id           uint32
         +--ro automatic-steering
            +--ro color?         -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/color
            +--ro end-point?     -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/end-point
            +--ro co-flag?       enumeration
            +--ro binding-sid?   -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/binding-sid



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   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv6-labeled-unicast:
   +--ro routes
      +--ro route* [prefix neighbor add-path-id]
         +--ro prefix                union
         +--ro neighbor              inet:ip-address
         +--ro add-path-id           uint32
         +--ro automatic-steering
            +--ro color?         -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/color
            +--ro end-point?     -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/end-point
            +--ro co-flag?       enumeration
            +--ro binding-sid?   -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/binding-sid
   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:l3vpn-ipv4-unicast:
   +--ro routes
      +--ro route* [rd prefix neighbor add-path-id]
         +--ro rd                    rt-types:route-distinguisher
         +--ro prefix                union
         +--ro neighbor              inet:ip-address
         +--ro add-path-id           uint32
         +--ro automatic-steering
            +--ro color?         -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/color
            +--ro end-point?     -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/end-point
            +--ro co-flag?       enumeration
            +--ro binding-sid?   -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/binding-sid
   augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:l3vpn-ipv6-unicast:
   +--ro routes
      +--ro route* [rd prefix neighbor add-path-id]
         +--ro rd                    rt-types:route-distinguisher
         +--ro prefix                union
         +--ro neighbor              inet:ip-address
         +--ro add-path-id           uint32
         +--ro automatic-steering
            +--ro color?         -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/color
            +--ro end-point?     -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/end-point
            +--ro co-flag?       enumeration
            +--ro binding-sid?   -> /rt:routing/control-plane-protocols/control-plane-protocol/bgp:bgp/global/ietf-bgp-srte:segment-routing/policy-state/sr-policy/binding-sid

 ...


4.  Yang Module


<CODE BEGINS> file "ietf-bgp-srte@2019-07-07.yang"

module ietf-bgp-srte {

  namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-srte";




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  prefix "ietf-bgp-srte";

  import ietf-routing-types {
    prefix rt-types;
  }

  import ietf-routing {
    prefix "rt";
  }

  import ietf-inet-types {
    prefix inet;
  }

  import ietf-bgp {
    prefix bgp;
  }

  import ietf-bgp-types {
    prefix bgp-types;
  }

  import ietf-srv6-types {
    prefix srv6-types;
  }

  organization
     "IETF Inter-Domain Routing Working Group";

  contact
     "Inter-Domain working group - idr@ietf.org";

  description
    "This YANG module defines a data model to configure and
     manage segment routing extensions in BGP.

     Terms and Acronyms

     AF : Address Family

     BGP (bgp) : Border Gateway Protocol

     SR : Segment Routing

     SID : Segment Identifier

     SRv6 : Segment Routing with IPv6 Data plane




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     VPN : Virtual Private Network

     VRF : Virtual Routing and Forwarding

    ";

  revision 2018-06-26 {
    description
      "Initial revision" ;
    reference "";
  }

  //
  // New identities and typedefs for SR extensions
  //

  // SR Policy SAFI identities
  identity IPV4_SRPOLICY {
    base bgp-types:afi-safi-type;
    description
     "IPv4 SR Policy (AFI,SAFI = 1,73)";
    reference "TBD";
  }

  identity IPV6_SRPOLICY {
    base bgp-types:afi-safi-type;
    description
      "IPv6 SR Policy (AFI,SAFI = 2,73)";
    reference "TBD";
  }

  typedef segment-type {
    type enumeration {
      enum segment-type-1 {
        value 1;
        description "SR-MPLS Label";
      }
      enum segment-type-2 {
        value 2;
        description "SRv6 SID";
      }
      enum segment-type-3 {
        value 3;
        description "IPv4 Prefix with optional SR Algorithm";
      }
      enum segment-type-4 {
        value 4;
        description "IPv6 Global Prefix with optional SR Algorithm for SR-MPLS";



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      }
      enum segment-type-5 {
        value 5;
        description "IPv4 Prefix with Local Interface ID";
      }
      enum segment-type-6 {
        value 6;
        description "IPv4 Addresses for link endpoints as Local, Remote pair";
      }
      enum segment-type-7 {
        value 7;
        description "IPv6 Prefix and Interface ID for link endpoints as Local,
           Remote pair for SR-MPLS";
      }
      enum segment-type-8 {
        value 8;
        description "IPv6 Addresses for link endpoints as Local, Remote pair for
           SR-MPLS";
      }
      enum segment-type-9 {
        value 9;
        description "IPv6 Global Prefix with optional SR Algorithm for SRv6";
      }
      enum segment-type-10 {
        value 10;
        description "IPv6 Prefix and Interface ID for link endpoints as Local,
           Remote pair for SRv6";
      }
      enum segment-type-11 {
        value 11;
        description "IPv6 Addresses for link endpoints as Local, Remote pair for
           SRv6";
      }
    }
    description "SR segment type";
  }

  // Sid type union
  typedef sid-type {
    type union {
      type rt-types:mpls-label;
      type srv6-types:srv6-sid;
    }
    description "Type definition for Segment Identifier. This is
                 a union type which can be either a SR MPLS SID in the
                 form of a label,  or a SRv6 SID in the form of
                 an IPv6 address.";
    reference "TBD";



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  }

  //
  // SR Policy Related Groupings
  //
  //Color and Endpoint of the SR Policy
  grouping sr-policy-color-endpoint {
    description "Common grouping for SR Policy Color and
                 Endpoint";
    leaf color {
      type uint32;
      description "Color of the policy";
    }

    leaf end-point {
      type inet:ip-address;
      description "Endpoint of the policy";
    }
  }
  // Authorized colors for On Demand SR Policy programming
  grouping sr-odn-auth-colors {
    description
      "Authorized colors for On Demand (dynamic) SR Policies
       towards BGP nexthops";
    container authorized-colors {
      config false;
      description
        "Authorized colors for On Demand (dynamic) SR policies
         towards BGP nexthops";
      list colors {
        key "color";
        description "List of SR Policy Colors";
        leaf color {
          type uint32;
          description "Color value";
        }
      }
    }
  }

  grouping sr-policy-cmn-state {
    description "Common state parameters applicable to
                 SR Policies";
    leaf policy-state {
      type enumeration {
        enum UP {
          description "SR Policy state UP";
        }



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        enum DOWN {
          description "SR Policy state DOWN";
        }
      }
      description "SR Policy forwarding state";
    }

    leaf binding-sid {
      type sid-type;
      description "Binding SID of the SR Policy";
    }

    leaf steering-disabled {
      type empty;
      description "This attribute is set if steering
                   is disabled on this SR policy";
    }

    leaf ref-count {
      type uint32;
      description "Count of routes steering over this policy";
    }
  }

  //
  // SR Policy State grouping
  //
  grouping sr-policy-state {
    description "SR Policy State";
    container policy-state {
      config false;
      description "SR Policy State";
      list sr-policy {
        key "color end-point";
        description "List of SR Policies";

        uses sr-policy-color-endpoint;

        // State of the SR Policy in BGP
        uses sr-policy-cmn-state;
      }
    }
  }

  grouping sr-exp-policy-cp-state {
    description "State of BGP signaled SR Policy (explicit)
                 candidate paths";
    container explicit-policies {



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      config false;
      description "BGP signaled explicit SR Policies";
      list sr-policy {
        key "distinguisher color end-point";
        description "List of BGP signaled explicit SR Policies";
        leaf distinguisher {
          type uint32;
          description "Distinguisher of the SR Policy
                       candidate path";
        }

        uses sr-policy-color-endpoint;

        leaf preference {
          type uint32;
          description "Preference of the SR Policy candidate path";
        }

        container explicit-binding-sid {
          description "Explicitly supplied Binding SID
                       for this policy";
          leaf binding-sid {
            type sid-type;
            description "Binding SID value";
          }
          leaf strict {
            type boolean;
            description "Boolean indicating that the node
                         must use only the supplied Binding SID
                         for this SR Policy.
                         reference: TBD";
          }
          leaf drop-on-invalid {
            type boolean;
            description "Boolean to indicate drop upon invalid
                         policy, behavior. This overwrites the
                         default behavior of fallback to IGP path
                         , when SR Policy is (or becomes) invalid.
                         reference: TBD";
          }
        }

        leaf usable {
          type boolean;
          description "Boolean to indicate that the SR Policy is
                       usable on this node.
                       reference: TBD";
        }



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        leaf registered {
          type boolean;
          description "Boolean to indicate that the SR policy
                       is registered with policy manager to
                       install the corresponding forwarding entry";

        }

        uses segment-lists;
        // TODO: Segment Lists and other parameters from SR Policy model
        //       to be imported here.
      }
    }
  }

  grouping segment-lists {
    description
      "Segment lists grouping";
    container segment-lists {
      description "Segment-lists properties";

      list segment-list {
        key "weight";
        description "Segment-list";
        leaf weight {
          type uint32;
          description "Segment-list weight";
        }
        container segments {
          description
            "Segments for given segment list";

          list segment {
            key "index";
            description "Segment/hop at the index";
            uses segment-properties;
          }
        }
      }
    }
  }

  grouping segment-properties {
    description "Segment properties grouping";
    leaf index {
      type uint32;
      description "Segment index";
    }



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    leaf type {
      type segment-type;
      description "Segment type";
    }
    container segment-types {
      description "Types of segments";
      container segment-type-1 {
        description
           "Segment declared by MPLS label";
        leaf sid-value {
           type rt-types:mpls-label;
           description "MPLS label value";
        }
      }
      container segment-type-2 {
        description
           "Segment declared by SRv6 SID value";
        leaf sid-value {
           type srv6-types:srv6-sid;
           description "SRv6 SID value";
        }
      }
      container segment-type-3 {
        description
           "Segment declared by IPv4 Prefix with optional SR Algorithm";
        leaf ipv4-address {
          type inet:ipv4-address;
          description "Segment IPv4 address";
        }
        leaf algorithm {
          type uint8;
          description "Prefix SID algorithm identifier";
        }
      }
      container segment-type-4 {
        description
           "Segment declared by IPv6 Global Prefix with optional
            SR Algorithm for SR-MPLS";
        leaf ipv6-address {
          type inet:ipv6-address;
          description "Segment IPv6 address";
        }
        leaf algorithm {
          type uint8;
          description "Prefix SID algorithm identifier";
        }
      }
      container segment-type-5 {



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        description
           "Segment declared by IPv4 Prefix with Local Interface ID";
        leaf ipv4-address {
          type inet:ipv4-address;
          description "Node IPv4 address";
        }
        leaf interface-identifier {
          type uint32;
          description "local interface identifier";
        }
      }
      container segment-type-6 {
        description
           "Segment declared by IPv4 Addresses for link endpoints
            as Local, Remote pair";
        leaf local-ipv4-address {
          type inet:ipv4-address;
          description "Segment local IPv4 adjacency address";
        }
        leaf remote-ipv4-address {
          type inet:ipv4-address;
          description "Segment remote IPv4 adjacency address";
        }
      }
      container segment-type-7 {
        description
           "Segment declared by IPv6 Prefix and Interface ID for
           link endpoints as Local, Remote pair for SR-MPLS";
        leaf local-ipv6-address {
          type inet:ipv6-address;
          description "Local link IPv6 address";
        }
        leaf local-interface-identifier {
          type uint32;
          description "Local interface identifier";
        }
        leaf remote-ipv6-address {
          type inet:ipv6-address;
          description "Remote link IPv6 address";
        }
        leaf remote-interface-identifier {
          type uint32;
          description "Remote interface identifier";
        }
      }
      container segment-type-8 {
        description
           "Segment declared by IPv6 Addresses for link endpoints as



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           Local, Remote pair for SR-MPLS";
        leaf local-ipv6-address {
          type inet:ipv6-address;
          description "Segment local IPv6 adjacency address";
        }
        leaf remote-ipv6-address {
          type inet:ipv6-address;
          description "Segment remote IPv6 adjacency address";
        }
      }
      container segment-type-9 {
        description
          "Segment declared by IPv6 Global Prefix with optional
           SR Algorithm for SRv6";
        leaf ipv6-address {
          type inet:ipv6-address;
          description "Segment IPv6 prefix";
        }
        leaf algorithm {
          type uint8;
          description "Prefix SID algorithm identifier";
        }
      }
      container segment-type-10 {
        description
           "Segment declared by IPv6 Prefix and Interface ID for
           link endpoints as Local, Remote pair for SRv6";
        leaf local-ipv6-address {
          type inet:ipv6-address;
          description "Local link IPv6 address";
        }
        leaf local-interface-identifier {
          type uint32;
          description "Local interface identifier";
        }
        leaf remote-ipv6-address {
          type inet:ipv6-address;
          description "Remote link IPv6 address";
        }
        leaf remote-interface-identifier {
          type uint32;
          description "Remote interface identifier";
        }
      }
      container segment-type-11 {
        description
           "Segment declared by IPv6 Addresses for link endpoints as
            Local, Remote pair for SRv6";



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          leaf local-ipv6-address {
            type inet:ipv6-address;
            description "Segment local IPv6 adjacency address";
          }
          leaf remote-ipv6-address {
            type inet:ipv6-address;
            description "Segment remote IPv6 adjacency address";
          }
      }
    }
  }
  grouping sr-odn-policies {
    description "SR On Demand (dynamic) SR Policies";
    container installed-policies {
      config false;
      description "BGP triggered On Demand (dynamic) SR Policies
                   corresponding to the BGP nexthops";
      list sr-policy {
        key "color end-point";
        description "SR Policy list";
        uses sr-policy-color-endpoint;
      }
    }
  }

  grouping sr-policy-steering-state {
    description "Per route Automatic Steering parameters";
    container automatic-steering {
      description "Per route Automatic Steering parameters";
      leaf color {
        type leafref {
          path "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
               "bgp:bgp/bgp:global/ietf-bgp-srte:segment-routing/" +
               "ietf-bgp-srte:policy-state/ietf-bgp-srte:sr-policy/" +
               "ietf-bgp-srte:color";
        }
        description "Color of the SR Policy being used for
                     Automatic Steering";
      }
      leaf end-point {
        type leafref {
          path "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
               "bgp:bgp/bgp:global/ietf-bgp-srte:segment-routing/" +
               "ietf-bgp-srte:policy-state/ietf-bgp-srte:sr-policy/" +
               "ietf-bgp-srte:end-point";
        }
        description "End-point of the SR Policy being used
                     for Automatic Steering";



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      }
      leaf co-flag {
        type enumeration {
          enum 00 {
            description "Color-Only flag 00";
          }
          enum 01 {
            description "Color-Only flag 01";
          }
          enum 10 {
            description "Color-Only flag 10";
          }
        }
        default "00";
        description "Color-Only (CO) flags applicable for
                     Automatic Steering of this route";
      }
      leaf binding-sid {
        type leafref {
          path "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
               "bgp:bgp/bgp:global/ietf-bgp-srte:segment-routing/" +
               "ietf-bgp-srte:policy-state/ietf-bgp-srte:sr-policy/" +
               "ietf-bgp-srte:binding-sid";
        }
        description "Binding SID of the SR Policy";
      }
    }
  }

  grouping route-key-leafs {
    description "Grouping for key leafs identifying a route";
    leaf prefix {
      type union {
         type inet:ip-prefix;
         type string;
      }
      description "BGP Prefix. This is a temp definition to
                  cover ip-prefix and other NLRI formats.
                  Import the type once defined in base
                  BGP RIB model";
    }
    leaf neighbor {
      type inet:ip-address;
      description "BGP Neighbor";
    }
    leaf add-path-id {
      type uint32;
      description "Add-path ID";



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    }
  }

  grouping common-bgp-route-grouping {
    description "BGP route list" ;
    container routes {
      config false;
      description "BGP Route in local RIB";
      list route {
        key "prefix neighbor add-path-id";
        description "BGP route list";
        uses route-key-leafs;
      }
    }
  }

  grouping common-bgp-vpn-route-grouping {
    description "BGP route list" ;
    container routes {
      config false;
      description "BGP VPN Route in local RIB";
      list route {
        key "rd prefix neighbor add-path-id";
        description "Route List";

        leaf rd {
          type rt-types:route-distinguisher;
          description "Route Distinguisher";
        }
        uses route-key-leafs;
      }
    }
  }

  //
  // BGP Specific Paramters
  //
  // Augment AF with route list
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv4-unicast" {
    description
      "Augment BGP SAFI route";
    uses common-bgp-route-grouping;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv6-unicast" {
    description
      "Augment BGP SAFI route";



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    uses common-bgp-route-grouping;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv4-labeled-unicast" {
    description
      "Augment BGP SAFI route";
    uses common-bgp-route-grouping;

  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:ipv6-labeled-unicast" {
    description
      "Augment BGP SAFI route";
    uses common-bgp-route-grouping;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:l3vpn-ipv4-unicast" {
    description
      "Augment BGP SAFI route";
    uses common-bgp-vpn-route-grouping;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi/bgp:l3vpn-ipv6-unicast" {
    description
      "Augment BGP SAFI route";
    uses common-bgp-vpn-route-grouping;
  }

  // SR Policy Related
  // On Demand authorized colors table
  // SR Policy state data
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global" {
    description
      "Segment Routing parameters in BGP global model";
    container segment-routing {
      description "Segment Routing parameters";
      container on-demand-policies {
        description
          "Segment Routing On Demand Nexthop
           (ODN) SR Policies";
        uses sr-odn-auth-colors;
        uses sr-odn-policies;
      }
      uses sr-policy-state;
    }
  }




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  // Steering state in overlay BGP routes
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/" +
          "bgp:afi-safi/bgp:ipv4-unicast/ietf-bgp-srte:routes/ietf-bgp-srte:route" {
    description
      "Augment BGP SAFI route with steering info";
    uses sr-policy-steering-state;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/" +
          "bgp:afi-safi/bgp:ipv6-unicast/ietf-bgp-srte:routes/ietf-bgp-srte:route" {
    description
      "Augment BGP SAFI route with steering info";
    uses sr-policy-steering-state;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/" +
          "bgp:afi-safi/bgp:ipv4-labeled-unicast/ietf-bgp-srte:routes/ietf-bgp-srte:route" {
    description
      "Augment BGP SAFI route with steering info";
    uses sr-policy-steering-state;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/" +
          "bgp:afi-safi/bgp:ipv6-labeled-unicast/ietf-bgp-srte:routes/ietf-bgp-srte:route" {
    description
      "Augment BGP SAFI route with steering info";
    uses sr-policy-steering-state;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/" +
          "bgp:afi-safi/bgp:l3vpn-ipv4-unicast/ietf-bgp-srte:routes/ietf-bgp-srte:route" {
    description
      "Augment BGP SAFI route with steering info";
    uses sr-policy-steering-state;
  }
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/" +
          "bgp:afi-safi/bgp:l3vpn-ipv6-unicast/ietf-bgp-srte:routes/ietf-bgp-srte:route" {
    description
      "Augment BGP SAFI route with steering info";
    uses sr-policy-steering-state;
  }

  // BGP Signaled SR Policy explicit candidate paths state
  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi" {
    description "Augment IPv4 SR Policy SAFI list entry";



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    container ipv4-srpolicy {
      when "../afi-safi-name = 'bgp-types:IPV4_SRPOLICY'" {
       description
         "Include this container for IPv4 SR Policy specific
          configuration";
      }
      description "IPv4 SR Policy specific parameters";
      uses sr-exp-policy-cp-state;
    }
  }

  augment "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/" +
          "bgp:bgp/bgp:global/bgp:afi-safis/bgp:afi-safi" {
    description "Augment IPv6 SR Policy SAFI list entry";
    container ipv6-srpolicy {
      when "../afi-safi-name = 'bgp-types:IPV6_SRPOLICY'" {
        description
          "Include this container for IPv6 SR Policy specific
           configuration";
      }
      description "IPv6 SR Policy specific parameters";
      uses sr-exp-policy-cp-state;
    }
  }
}
<CODE ENDS>


5.  Contributors

   Dhanendra Jain
   Cisco Systems
   US

   Email: dhanendra.ietf@gmail.com

   Zhichun Jiang
   Cisco Systems
   US

   Email: zcjiang@tencent.com

   Zafar Ali
   Cisco Systems
   US

   Email: zali@cisco.com




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   Sharmila Palani
   Cisco Systems
   US

   Email: spalani@cisco.com

6.  IANA Considerations

7.  Security Considerations

   The transport protocol used for sending the BGP Segment Routing data
   MUST support authentication and SHOULD support encryption.  The data-
   model by itself does not create any security implications.

   This draft does not change any underlying security issues inherent in
   [I-D.ietf-idr-bgp-model].

8.  Acknowledgements

   TBD.

9.  References

9.1.  Normative References

   [I-D.ietf-idr-bgp-model]
              Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP
              YANG Model for Service Provider Networks", draft-ietf-idr-
              bgp-model-09 (work in progress), June 2020.

   [I-D.ietf-idr-segment-routing-te-policy]
              Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P.,
              Rosen, E., Jain, D., and S. Lin, "Advertising Segment
              Routing Policies in BGP", draft-ietf-idr-segment-routing-
              te-policy-09 (work in progress), May 2020.

   [I-D.ietf-spring-segment-routing-policy]
              Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
              P. Mattes, "Segment Routing Policy Architecture", draft-
              ietf-spring-segment-routing-policy-08 (work in progress),
              July 2020.

   [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>.





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   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [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>.

   [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>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

9.2.  Informative References

   [I-D.ietf-spring-srv6-network-programming]
              Filsfils, C., Camarillo, P., Leddy, J., Voyer, D.,
              Matsushima, S., and Z. Li, "SRv6 Network Programming",
              draft-ietf-spring-srv6-network-programming-16 (work in
              progress), June 2020.

   [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>.

   [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>.

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.







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Internet-Draft    Yang Model for BGP Segment Routing TE        July 2020


Authors' Addresses

   Krishna Deevi
   Cisco
   170 W. Tasman Drive
   San Jose, CA  95134
   USA

   Email: kdeevi@cisco.com


   Kamran Raza
   Cisco
   2000 Innovation Drive
   Kanata, ON  K2K-3E8
   CA

   Email: skraza@cisco.com


   Kausik Majumdar
   Commscope

   Email: kausik.majumdar@comscope.com


   Bruno Decraene
   Orange
   France

   Email: bruno.decraene@orange.com


   Zhichun Jiang
   Tencent

   Email: zcjiang@tencent.com














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