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Versions: (draft-shaikh-idr-bgp-model) 00 01 02 03 04 05 06

Interdomain Routing                                             K. Patel
Internet-Draft                                                    Arrcus
Intended status: Standards Track                         M. Jethanandani
Expires: August 29, 2019                                          VMware
                                                                S. Hares
                                                                  Huawei
                                                       February 25, 2019


              BGP YANG Model for Service Provider Networks
                      draft-ietf-idr-bgp-model-04

Abstract

   This document defines a YANG data model for configuring and managing
   BGP, including protocol, policy, and operational aspects based on
   data center, carrier and content provider operational requirements.

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 August 29, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Goals and approach  . . . . . . . . . . . . . . . . . . .   3
     1.2.  Note to RFC Editor  . . . . . . . . . . . . . . . . . . .   4
   2.  Model overview  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  BGP protocol configuration  . . . . . . . . . . . . . . .   5
     2.2.  Policy configuration overview . . . . . . . . . . . . . .   7
     2.3.  BGP RIB overview  . . . . . . . . . . . . . . . . . . . .   8
       2.3.1.  Local Routing . . . . . . . . . . . . . . . . . . . .  20
       2.3.2.  Pre updates per-neighbor  . . . . . . . . . . . . . .  20
       2.3.3.  Post updates per-neighbor . . . . . . . . . . . . . .  20
       2.3.4.  Pre route advertisements per-neighbor . . . . . . . .  20
       2.3.5.  Post route advertisements per-neighbor  . . . . . . .  20
   3.  Relation to other YANG data models  . . . . . . . . . . . . .  21
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  21
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  21
     5.1.  URI Registration  . . . . . . . . . . . . . . . . . . . .  21
     5.2.  YANG Module Name Registration . . . . . . . . . . . . . .  22
   6.  YANG modules  . . . . . . . . . . . . . . . . . . . . . . . .  23
   7.  Structure of the YANG modules . . . . . . . . . . . . . . . .  23
     7.1.  Main module and submodules for base items . . . . . . . .  23
     7.2.  BGP types . . . . . . . . . . . . . . . . . . . . . . . .  60
     7.3.  BGP policy data . . . . . . . . . . . . . . . . . . . . .  70
     7.4.  RIB modules . . . . . . . . . . . . . . . . . . . . . . .  81
   8.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . 132
     8.1.  Creating BGP Instance . . . . . . . . . . . . . . . . . . 132
     8.2.  Neighbor Address Family Configuration . . . . . . . . . . 133
   9.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . . 135
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 135
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . . 135
     11.1.  Normative references . . . . . . . . . . . . . . . . . . 135
     11.2.  Informative references . . . . . . . . . . . . . . . . . 137
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 137

1.  Introduction

   This document describes a YANG [RFC7950] data model for the BGP
   [RFC4271] protocol, including various protocol extensions, policy
   configuration, as well as defining key operational state data,
   including Routing Information Base (RIB).  The model is intended to
   be vendor-neutral, in order to allow operators to manage BGP
   configuration in heterogeneous environments with routers supplied by
   multiple vendors.  The model is also intended to be readily mapped to




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   existing implementations to facilitate support from as large a set of
   routing hardware and software vendors as possible.

1.1.  Goals and approach

   The model covers the base BGP features that are deployed across major
   implementations and the common BGP configurations in use across a
   number of operator network deployments.  In particular, this model
   attempts to cover BGP features defined in BGP [RFC4271], BGP
   Communities Attribute [RFC1997], BGP Route Reflection [RFC4456],
   Multiprotocol Extensions for BGP-4 [RFC4760], Autonomous System
   Confederations for BGP [RFC5065], BGP Route Flap Damping [RFC2439],
   Graceful Restart Mechanism for BGP [RFC4724], and BGP Prefix Origin
   Validation [RFC6811].

   Along with configuration of base BGP features, this model also
   addresses policy configuration, by providing "hooks" for applying
   policies, and also defining BGP-specific policy features.  The BGP
   policy features are intended to be used with the general routing
   policy model defined in A YANG Data Model for Routing Policy
   Management [I-D.ietf-rtgwg-policy-model].  The model conforms to the
   NMDA [RFC8342] architecture.

   For the base BGP features, the focus of the model described in this
   document is on providing configuration and operational state
   information relating to:

   o  The global BGP instance, and neighbors whose configuration is
      specified individually, or templated with the use of peer-groups.

   o  The address families that are supported by peers, and the global
      configuration which relates to them.

   o  The policy configuration "hooks" and BGP-specific policy features
      that relate to a neighbor - controlling the import and export of
      NLRIs.

   o  RIB contents.

   As mentioned earlier, any configuration items that are deemed to be
   widely available in existing major BGP implementations are included
   in the model.  Additional, more esoteric, configuration items that
   are not commonly used, or only available from a single
   implementation, are omitted from the model with an expectation that
   they will be available in companion modules that augment or extend
   the current model.  This allows clarity in identifying data that is
   part of the vendor-neutral base model.




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   Where possible, naming in the model follows conventions used in
   available standards documents, and otherwise tries to be self-
   explanatory with sufficient descriptions of the intended behavior.
   Similarly, configuration data value constraints and default values,
   where used, are based on recommendations in current standards
   documentation, or those commonly used in multiple implementations.
   Since implementations can vary widely in this respect, this version
   of the model specifies only a limited set of defaults and ranges with
   the expectation of being more prescriptive in future versions based
   on actual operator use.

1.2.  Note to RFC Editor

   This document uses several placeholder values throughout the
   document.  Please replace them as follows and remove this note before
   publication.

   RFC XXXX, where XXXX is the number assigned to this document at the
   time of publication.

   2019-02-25 with the actual date of the publication of this document.

   RFC ZZZZ, where ZZZZ is the number assigned to A YANG Data Model for
   Routing Policy Management [I-D.ietf-rtgwg-policy-model].

2.  Model overview

   The BGP model is defined across several YANG modules and submodules,
   but at a high level is organized into six elements:

   o  base protocol configuration -- configuration affecting BGP
      protocol-related operations, defined at various levels of
      hierarchy.

   o  multiprotocol configuration -- configuration affecting individual
      address-families within BGP Multiprotocol Extensions for BGP-4
      [RFC4760].

   o  neighbor configuration -- configuration affecting an individual
      neighbor within BGP.

   o  neighbor multiprotocol configuration -- configuration affecting
      individual address-families for a neighbor within BGP.

   o  policy configuration -- hooks for application of the policies
      defined in A YANG Data Model for Routing Policy Management
      [I-D.ietf-rtgwg-policy-model] that act on routes sent (received)




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      to (from) peers or other routing protocols and BGP-specific policy
      features.

   o  operational state -- variables used for monitoring and management
      of BGP operations.

   These modules also make use of standard Internet types, such as IP
   addresses and prefixes, autonomous system numbers, etc., defined in
   Common YANG Data Types [RFC6991].

2.1.  BGP protocol configuration

   The BGP protocol configuration model is organized hierarchically,
   much like the majority of router implementations.  That is,
   configuration items can be specified at multiple levels, as shown
   below.

                 +--rw bgp
                    +--rw global!
                    |  +-- (global-configuration-options)
                    +--rw neighbors
                    |  +--rw neighbor* [neighbor-address]
                    |  +-- (neighbor-configuration-options)
                    +--rw peer-groups
                       +--rw peer-group* [peer-group-name]
                       +-- (neighbor-configuration-options)

   Users may specify configuration at a higher level and have it apply
   to all lower-level items, or provide overriding configuration at a
   lower level of the hierarchy.  Overriding configuration items are
   optional, with neighbor specific configuration being the most
   specific or lowest level, followed by peer-group, and finally global.
   Global configuration options reflect a subset of the peer-group or
   neighbor specific configuration options which are relevant to the
   entire BGP instance.

   The model makes the simplifying assumption that most of the
   configuration items are available at all levels of the hierarchy.
   That is, very little configuration is specific to a particular level
   in the hierarchy, other than obvious items such as "group-name" only
   being available for the peer group-level config.  A notable exception
   is for sub-address family configuration where some items are only
   applicable for a given AFI-SAFI combination.

   In order to allow common configuration to be applied to a set of
   neighbors, all neighbor configuration options are available within a
   peer-group.  A neighbor is associated to a particular peer-group




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   through the use of a peer-group leaf (which provides a reference to a
   configured item in the peer-group list).

   Address-family configuration is made available in multiple points
   within the model - primarily within the global container, where
   instance-wide configuration can be set (for example, global protocol
   parameters, the BGP best path route selection options, or global
   policies relating to the address-family); and on a per-neighbor or
   per-peer-group basis, where address-families can be enabled or
   disabled, and policy associated with the parent entity applied.
   Within the afi-safi container, generic configuration that applies to
   all address-families (e.g., whether the AFI-SAFI is enabled) is
   presented at the top-level, with address-family specific containers
   made available for options relating to only that AFI-SAFI.  Within
   the current revision of the model a generic set of address-families,
   and common configuration and state options are included - further
   work is expected to add additional parameters to this area of the
   model.

   The following address-families are currently supported by the model:

           +--rw bgp
             +--rw global!
                +--rw afi-safis
                   +--rw afi-safi* [afi-safi-name]
                      +--rw afi-safi-name              identityref
                      |
                      +--rw ipv4-unicast
                      |     ...
                      +--rw ipv6-unicast
                      |     ...
                      +--rw ipv4-labeled-unicast
                      |     ...
                      +--rw ipv6-labeled-unicast
                      |     ...
                      +--rw l3vpn-ipv4-unicast
                      |     ...
                      +--rw l3vpn-ipv6-unicast
                      |     ...
                      +--rw l3vpn-ipv4-multicast
                      |     ...
                      +--rw l3vpn-ipv6-multicast
                      |     ...
                      +--rw l2vpn-vpls
                      |     ...
                      +--rw l2vpn-evpn
                      |     ...




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2.2.  Policy configuration overview

   The BGP policy configuration model augments the generic YANG routing
   policy model described in A YANG Data Model for Routing Policy
   Management [I-D.ietf-rtgwg-policy-model], which represents a
   condition-action policy framework for routing.  This model adds BGP-
   specific conditions (e.g., matching on the community attribute), and
   actions (e.g., setting local preference) to the generic policy
   framework.

   Policies that are defined in the routing-policy model are referenced
   in multiple places within the model:

   o  within the global instance, where a policy applies to all address-
      families for all peers.

   o  on a global AFI-SAFI basis, where policies apply to all peers for
      a particular address-family.

   o  on a per-peer-group or per-neighbor basis - where the policy
      applies to all address-families for the particular group or
      neighbor.

   o  on a per-afi-safi basis within a neighbor or peer-group context,
      where the policy is specific to the AFI-SAFI for a a specific
      neighbor or group.

              +--rw bgp
                 +--rw global!
                 |  +--rw afi-safis
                 |     +--rw afi-safi
                 |     |  +--rw afi-safi* [afi-safi-name]
                 |     |     +--rw apply-policy
                 |     +--rw apply-policy
                 +--rw neighbors
                 |  +--rw neighbor* [neighbor-address]
                 |     +--rw afi-safi
                 |     |  +--rw afi-safi* [afi-safi-name]
                 |     |     +--rw apply-policy
                 |     +--rw apply-policy
                 +--rw peer-groups
                    +--rw peer-group* [peer-group-name]
                       +--rw afi-safi
                       |  +--rw afi-safi* [afi-safi-name]
                       |     +--rw apply-policy
                       +--rw apply-policy





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2.3.  BGP RIB overview

   The RIB data model represents the BGP RIB contents.  The model
   supports five logical RIBs per address family.

   A version of the tree showing the five logical RIBs is shown below.


   module: ietf-bgp-rib
     augment /rt:routing/rt:ribs:
       +--ro rib
          +--ro attr-sets
          |  +--ro attr-set* [index]
          |     +--ro index                   uint64
          |     +--ro origin?                 bgpt:bgp-origin-attr-type
          |     +--ro atomic-aggregate?       boolean
          |     +--ro next-hop?               inet:ip-address
          |     +--ro med?                    uint32
          |     +--ro local-pref?             uint32
          |     +--ro originator-id?          inet:ipv4-address
          |     +--ro cluster-list*           inet:ipv4-address
          |     +--ro aigp?                   uint64
          |     +--ro aggregator
          |     |  +--ro as?        inet:as-number
          |     |  +--ro as4?       inet:as-number
          |     |  +--ro address?   inet:ipv4-address
          |     +--ro as-path
          |     |  +--ro segment* [type]
          |     |     +--ro type      identityref
          |     |     +--ro member*   inet:as-number
          |     +--ro as4-path
          |     |  +--ro segment* [type]
          |     |     +--ro type      identityref
          |     |     +--ro member*   inet:as-number
          |     +--ro tunnel-encapsulation
          |        +--ro tunnels
          |           +--ro tunnel* [type]
          |              +--ro type       identityref
          |              +--ro subtlvs
          |                 +--ro subtlv* [type]
          |                    +--ro type                identityref
          |                    +--ro colors*             uint32
          |                    +--ro preference?         uint32
          |                    +--ro binding-sid?        string
          |                    +--ro remote-endpoints
          |                    |  +--ro remote-endpoint* [endpoint]
          |                    |     +--ro as?         inet:as-number
          |                    |     +--ro endpoint    inet:ip-address



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          |                    +--ro segment-lists
          |                       +--ro segment-list* [instance-id]
          |                          +--ro instance-id    uint64
          |                          +--ro weight?        uint32
          |                          +--ro segments
          |                             +--ro segment* [index]
          |                                +--ro index
          |                                |       uint64
          |                                +--ro type?
          |                                |       enumeration
          |                                +--ro sid?
          |                                |       string
          |                                +--ro mpls-tc?
          |                                |       uint8
          |                                +--ro mpls-bos?
          |                                |       boolean
          |                                +--ro mpls-ttl?
          |                                |       uint8
          |                                +--ro remote-ipv4-address?
          |                                |       inet:ipv4-address
          |                                +--ro local-ipv4-address?
          |                                |       inet:ipv4-address
          |                                +--ro remote-ipv6-address?
          |                                |       inet:ipv6-address
          |                                +--ro local-ipv6-address?
          |                                |       inet:ipv6-address
          |                                +--ro local-interface-id?
          |                                        uint32
          +--ro communities
          |  +--ro community* [index]
          |     +--ro index        uint64
          |     +--ro community*   union
          +--ro ext-communities
          |  +--ro ext-community* [index]
          |     +--ro index            uint64
          |     +--ro ext-community*   bgpt:bgp-ext-community-type
          +--ro afi-safis
             +--ro afi-safi* [afi-safi-name]
                +--ro afi-safi-name       identityref
                +--ro ipv4-unicast
                |  +--ro loc-rib
                |  |  +--ro routes
                |  |     +--ro route* [prefix origin path-id]
                |  |        +--ro prefix
                |  |        |       inet:ipv4-prefix
                |  |        +--ro origin                 union
                |  |        +--ro path-id                uint32
                |  |        +--ro attr-index?            leafref



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                |  |        +--ro community-index?       leafref
                |  |        +--ro ext-community-index?   leafref
                |  |        +--ro last-modified?         types:timeticks
                |  |        +--ro valid-route?           boolean
                |  |        +--ro invalid-reason?        identityref
                |  |        +--ro unknown-attributes
                |  |           +--ro unknown-attribute* [attr-type]
                |  |              +--ro optional?     boolean
                |  |              +--ro transitive?   boolean
                |  |              +--ro partial?      boolean
                |  |              +--ro extended?     boolean
                |  |              +--ro attr-type     uint8
                |  |              +--ro attr-len?     uint16
                |  |              +--ro attr-value?   binary
                |  +--ro neighbors
                |     +--ro neighbor* [neighbor-address]
                |        +--ro neighbor-address    inet:ip-address
                |        +--ro adj-rib-in-pre
                |        |  +--ro routes
                |        |     +--ro route* [prefix path-id]
                |        |        +--ro prefix
                |        |        |       inet:ipv4-prefix
                |        |        +--ro path-id                uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-in-post
                |        |  +--ro routes
                |        |     +--ro route* [prefix path-id]
                |        |        +--ro prefix
                |        |        |       inet:ipv4-prefix
                |        |        +--ro path-id                uint32
                |        |        +--ro attr-index?            leafref



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                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro best-path?             boolean
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-out-pre
                |        |  +--ro routes
                |        |     +--ro route* [prefix path-id]
                |        |        +--ro prefix
                |        |        |       inet:ipv4-prefix
                |        |        +--ro path-id                uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-out-post
                |           +--ro routes
                |              +--ro route* [prefix path-id]
                |                 +--ro prefix
                |                 |       inet:ipv4-prefix
                |                 +--ro path-id                uint32



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                |                 +--ro attr-index?            leafref
                |                 +--ro community-index?       leafref
                |                 +--ro ext-community-index?   leafref
                |                 +--ro last-modified?
                |                 |       types:timeticks
                |                 +--ro valid-route?           boolean
                |                 +--ro invalid-reason?
                |                 |       identityref
                |                 +--ro unknown-attributes
                |                    +--ro unknown-attribute*
                |                            [attr-type]
                |                       +--ro optional?     boolean
                |                       +--ro transitive?   boolean
                |                       +--ro partial?      boolean
                |                       +--ro extended?     boolean
                |                       +--ro attr-type     uint8
                |                       +--ro attr-len?     uint16
                |                       +--ro attr-value?   binary
                +--ro ipv6-unicast
                |  +--ro loc-rib
                |  |  +--ro routes
                |  |     +--ro route* [prefix origin path-id]
                |  |        +--ro prefix
                |  |        |       inet:ipv6-prefix
                |  |        +--ro origin                 union
                |  |        +--ro path-id                uint32
                |  |        +--ro attr-index?            leafref
                |  |        +--ro community-index?       leafref
                |  |        +--ro ext-community-index?   leafref
                |  |        +--ro last-modified?         types:timeticks
                |  |        +--ro valid-route?           boolean
                |  |        +--ro invalid-reason?        identityref
                |  |        +--ro unknown-attributes
                |  |           +--ro unknown-attribute* [attr-type]
                |  |              +--ro optional?     boolean
                |  |              +--ro transitive?   boolean
                |  |              +--ro partial?      boolean
                |  |              +--ro extended?     boolean
                |  |              +--ro attr-type     uint8
                |  |              +--ro attr-len?     uint16
                |  |              +--ro attr-value?   binary
                |  +--ro neighbors
                |     +--ro neighbor* [neighbor-address]
                |        +--ro neighbor-address    inet:ip-address
                |        +--ro adj-rib-in-pre
                |        |  +--ro routes
                |        |     +--ro route* [prefix path-id]
                |        |        +--ro prefix



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                |        |        |       inet:ipv6-prefix
                |        |        +--ro path-id                uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-in-post
                |        |  +--ro routes
                |        |     +--ro route* [prefix path-id]
                |        |        +--ro prefix
                |        |        |       inet:ipv6-prefix
                |        |        +--ro path-id                uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro best-path?             boolean
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-out-pre
                |        |  +--ro routes
                |        |     +--ro route* [prefix path-id]



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                |        |        +--ro prefix
                |        |        |       inet:ipv6-prefix
                |        |        +--ro path-id                uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-out-post
                |           +--ro routes
                |              +--ro route* [prefix path-id]
                |                 +--ro prefix
                |                 |       inet:ipv6-prefix
                |                 +--ro path-id                uint32
                |                 +--ro attr-index?            leafref
                |                 +--ro community-index?       leafref
                |                 +--ro ext-community-index?   leafref
                |                 +--ro last-modified?
                |                 |       types:timeticks
                |                 +--ro valid-route?           boolean
                |                 +--ro invalid-reason?
                |                 |       identityref
                |                 +--ro unknown-attributes
                |                    +--ro unknown-attribute*
                |                            [attr-type]
                |                       +--ro optional?     boolean
                |                       +--ro transitive?   boolean
                |                       +--ro partial?      boolean
                |                       +--ro extended?     boolean
                |                       +--ro attr-type     uint8
                |                       +--ro attr-len?     uint16
                |                       +--ro attr-value?   binary
                +--ro ipv4-srte-policy
                |  +--ro loc-rib
                |  |  +--ro routes



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                |  |     +--ro route* [path-id endpoint color]
                |  |        +--ro path-id                uint32
                |  |        +--ro endpoint               inet:ip-address
                |  |        +--ro color                  uint32
                |  |        +--ro attr-index?            leafref
                |  |        +--ro community-index?       leafref
                |  |        +--ro ext-community-index?   leafref
                |  |        +--ro last-modified?         types:timeticks
                |  |        +--ro valid-route?           boolean
                |  |        +--ro invalid-reason?        identityref
                |  |        +--ro unknown-attributes
                |  |           +--ro unknown-attribute* [attr-type]
                |  |              +--ro optional?     boolean
                |  |              +--ro transitive?   boolean
                |  |              +--ro partial?      boolean
                |  |              +--ro extended?     boolean
                |  |              +--ro attr-type     uint8
                |  |              +--ro attr-len?     uint16
                |  |              +--ro attr-value?   binary
                |  +--ro neighbors
                |     +--ro neighbor* [neighbor-address]
                |        +--ro neighbor-address    inet:ip-address
                |        +--ro adj-rib-in-pre
                |        |  +--ro routes
                |        |     +--ro route* [path-id endpoint color]
                |        |        +--ro path-id                uint32
                |        |        +--ro endpoint
                |        |        |       inet:ip-address
                |        |        +--ro color                  uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-in-post



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                |        |  +--ro routes
                |        |     +--ro route* [path-id endpoint color]
                |        |        +--ro path-id                uint32
                |        |        +--ro endpoint
                |        |        |       inet:ip-address
                |        |        +--ro color                  uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro best-path?             boolean
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8
                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-out-pre
                |        |  +--ro routes
                |        |     +--ro route* [path-id endpoint color]
                |        |        +--ro path-id                uint32
                |        |        +--ro endpoint
                |        |        |       inet:ip-address
                |        |        +--ro color                  uint32
                |        |        +--ro attr-index?            leafref
                |        |        +--ro community-index?       leafref
                |        |        +--ro ext-community-index?   leafref
                |        |        +--ro last-modified?
                |        |        |       types:timeticks
                |        |        +--ro valid-route?           boolean
                |        |        +--ro invalid-reason?
                |        |        |       identityref
                |        |        +--ro unknown-attributes
                |        |           +--ro unknown-attribute*
                |        |                   [attr-type]
                |        |              +--ro optional?     boolean
                |        |              +--ro transitive?   boolean
                |        |              +--ro partial?      boolean
                |        |              +--ro extended?     boolean
                |        |              +--ro attr-type     uint8



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                |        |              +--ro attr-len?     uint16
                |        |              +--ro attr-value?   binary
                |        +--ro adj-rib-out-post
                |           +--ro routes
                |              +--ro route* [path-id endpoint color]
                |                 +--ro path-id                uint32
                |                 +--ro endpoint
                |                 |       inet:ip-address
                |                 +--ro color                  uint32
                |                 +--ro attr-index?            leafref
                |                 +--ro community-index?       leafref
                |                 +--ro ext-community-index?   leafref
                |                 +--ro last-modified?
                |                 |       types:timeticks
                |                 +--ro valid-route?           boolean
                |                 +--ro invalid-reason?
                |                 |       identityref
                |                 +--ro unknown-attributes
                |                    +--ro unknown-attribute*
                |                            [attr-type]
                |                       +--ro optional?     boolean
                |                       +--ro transitive?   boolean
                |                       +--ro partial?      boolean
                |                       +--ro extended?     boolean
                |                       +--ro attr-type     uint8
                |                       +--ro attr-len?     uint16
                |                       +--ro attr-value?   binary
                +--ro ipv6-srte-policy
                   +--ro loc-rib
                   |  +--ro routes
                   |     +--ro route* [path-id endpoint color]
                   |        +--ro path-id                uint32
                   |        +--ro endpoint               inet:ip-address
                   |        +--ro color                  uint32
                   |        +--ro attr-index?            leafref
                   |        +--ro community-index?       leafref
                   |        +--ro ext-community-index?   leafref
                   |        +--ro last-modified?         types:timeticks
                   |        +--ro valid-route?           boolean
                   |        +--ro invalid-reason?        identityref
                   |        +--ro unknown-attributes
                   |           +--ro unknown-attribute* [attr-type]
                   |              +--ro optional?     boolean
                   |              +--ro transitive?   boolean
                   |              +--ro partial?      boolean
                   |              +--ro extended?     boolean
                   |              +--ro attr-type     uint8
                   |              +--ro attr-len?     uint16



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                   |              +--ro attr-value?   binary
                   +--ro neighbors
                      +--ro neighbor* [neighbor-address]
                         +--ro neighbor-address    inet:ip-address
                         +--ro adj-rib-in-pre
                         |  +--ro routes
                         |     +--ro route* [path-id endpoint color]
                         |        +--ro path-id                uint32
                         |        +--ro endpoint
                         |        |       inet:ip-address
                         |        +--ro color                  uint32
                         |        +--ro attr-index?            leafref
                         |        +--ro community-index?       leafref
                         |        +--ro ext-community-index?   leafref
                         |        +--ro last-modified?
                         |        |       types:timeticks
                         |        +--ro valid-route?           boolean
                         |        +--ro invalid-reason?
                         |        |       identityref
                         |        +--ro unknown-attributes
                         |           +--ro unknown-attribute*
                         |                   [attr-type]
                         |              +--ro optional?     boolean
                         |              +--ro transitive?   boolean
                         |              +--ro partial?      boolean
                         |              +--ro extended?     boolean
                         |              +--ro attr-type     uint8
                         |              +--ro attr-len?     uint16
                         |              +--ro attr-value?   binary
                         +--ro adj-rib-in-post
                         |  +--ro routes
                         |     +--ro route* [path-id endpoint color]
                         |        +--ro path-id                uint32
                         |        +--ro endpoint
                         |        |       inet:ip-address
                         |        +--ro color                  uint32
                         |        +--ro attr-index?            leafref
                         |        +--ro community-index?       leafref
                         |        +--ro ext-community-index?   leafref
                         |        +--ro last-modified?
                         |        |       types:timeticks
                         |        +--ro valid-route?           boolean
                         |        +--ro invalid-reason?
                         |        |       identityref
                         |        +--ro best-path?             boolean
                         |        +--ro unknown-attributes
                         |           +--ro unknown-attribute*
                         |                   [attr-type]



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                         |              +--ro optional?     boolean
                         |              +--ro transitive?   boolean
                         |              +--ro partial?      boolean
                         |              +--ro extended?     boolean
                         |              +--ro attr-type     uint8
                         |              +--ro attr-len?     uint16
                         |              +--ro attr-value?   binary
                         +--ro adj-rib-out-pre
                         |  +--ro routes
                         |     +--ro route* [path-id endpoint color]
                         |        +--ro path-id                uint32
                         |        +--ro endpoint
                         |        |       inet:ip-address
                         |        +--ro color                  uint32
                         |        +--ro attr-index?            leafref
                         |        +--ro community-index?       leafref
                         |        +--ro ext-community-index?   leafref
                         |        +--ro last-modified?
                         |        |       types:timeticks
                         |        +--ro valid-route?           boolean
                         |        +--ro invalid-reason?
                         |        |       identityref
                         |        +--ro unknown-attributes
                         |           +--ro unknown-attribute*
                         |                   [attr-type]
                         |              +--ro optional?     boolean
                         |              +--ro transitive?   boolean
                         |              +--ro partial?      boolean
                         |              +--ro extended?     boolean
                         |              +--ro attr-type     uint8
                         |              +--ro attr-len?     uint16
                         |              +--ro attr-value?   binary
                         +--ro adj-rib-out-post
                            +--ro routes
                               +--ro route* [path-id endpoint color]
                                  +--ro path-id                uint32
                                  +--ro endpoint
                                  |       inet:ip-address
                                  +--ro color                  uint32
                                  +--ro attr-index?            leafref
                                  +--ro community-index?       leafref
                                  +--ro ext-community-index?   leafref
                                  +--ro last-modified?
                                  |       types:timeticks
                                  +--ro valid-route?           boolean
                                  +--ro invalid-reason?
                                  |       identityref
                                  +--ro unknown-attributes



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                                     +--ro unknown-attribute*
                                             [attr-type]
                                        +--ro optional?     boolean
                                        +--ro transitive?   boolean
                                        +--ro partial?      boolean
                                        +--ro extended?     boolean
                                        +--ro attr-type     uint8
                                        +--ro attr-len?     uint16
                                        +--ro attr-value?   binary


2.3.1.  Local Routing

   The loc-rib is the main BGP routing table for the local routing
   instance, containing best-path selections for each prefix.  The loc-
   rib table may contain multiple routes for a given prefix, with an
   attribute to indicate which was selected as the best path.  Note that
   multiple paths may be used or advertised even if only one path is
   marked as best, e.g., when using BGP add-paths.  An implementation
   may choose to mark multiple paths in the RIB as best path by setting
   the flag to true for multiple entries.

2.3.2.  Pre updates per-neighbor

   The adj-rib-in-pre table is a per-neighbor table containing the NLRI
   updates received from the neighbor before any local input policy
   rules or filters have been applied.  This can be considered the 'raw'
   updates from a given neighbor.

2.3.3.  Post updates per-neighbor

   The adj-rib-in-post table is a per-neighbor table containing the
   routes received from the neighbor that are eligible for best-path
   selection after local input policy rules have been applied.

2.3.4.  Pre route advertisements per-neighbor

   The adj-rib-out-pre table is a per-neighbor table containing routes
   eligible for sending (advertising) to the neighbor before output
   policy rules have been applied.

2.3.5.  Post route advertisements per-neighbor

   The adj-rib-out-post table is a per-neighbor table containing routes
   eligible for sending (advertising) to the neighbor after output
   policy rules have been applied





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3.  Relation to other YANG data models

   The BGP model augments the Routing Management model A YANG Data Model
   for Routing Management [RFC8349] which defines the notion of routing,
   routing protocols, routing instances, or VRFs, and RIBs.

4.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that 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 (NACM) [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.

   There are a number of data nodes defined in this YANG module 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.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   Some of the RPC operations in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control access to these operations.  These are the
   operations and their sensitivity/vulnerability:

5.  IANA Considerations

   This document registers six URIs and six YANG modules.

5.1.  URI Registration

   in the IETF XML registry [RFC3688] [RFC3688].  Following the format
   in RFC 3688, the following registration is requested to be made:





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   URI: urn:ietf:params:xml:ns:yang:ietf-bgp
   URI: urn:ietf:params:xml:ns:yang:ietf-bgp-policy
   URI: urn:ietf:params:xml:ns:yang:ietf-bgp-types
   URI: urn:ietf:params:xml:ns:yang:ietf-bgp-rib
   URI: urn:ietf:params:xml:ns:yang:ietf-bgp-rib-ext
   URI: urn:ietf:params:xml:ns:yang:ietf-bgp-rib-types

   Registrant Contact: The IESG.  XML: N/A, the requested URI is an XML
   namespace.

5.2.  YANG Module Name Registration

   This document registers three YANG module in the YANG Module Names
   registry YANG [RFC6020].

   name: ietf-bgp
   namespace: urn:ietf:params:xml:ns:yang:ietf-bgp
   prefix: bgp
   reference: RFC XXXX

   name: ietf-bgp-policy
   namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-policy
   prefix: bp
   reference: RFC XXXX

   name: ietf-bgp-types
   namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-types
   prefix: bt
   reference: RFC XXXX

   name: ietf-bgp-rib
   namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-rib
   prefix: br
   reference: RFC XXXX

   name: ietf-bgp-rib-ext
   namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-rib-ext
   prefix: bre
   reference: RFC XXXX

   name: ietf-bgp-rib-types
   namespace: urn:ietf:params:xml:ns:yang:ietf-bgp-rib-types
   prefix: brt
   reference: RFC XXXX







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6.  YANG modules

   The modules comprising the BGP configuration and operational model
   are described by the YANG modules and submodules in the sections
   below.

   The main module, ietf-bgp.yang, includes the following submodules:

   o  ietf-bgp-common - defines the groupings that are common across
      more than one context (where contexts are neighbor, group, global)

   o  ietf-bgp-common-multiprotocol - defines the groupings that are
      common across more than one context, and relate to multiprotocol
      BGP

   o  ietf-bgp-common-structure - defines groupings that are shared by
      multiple contexts, but are used only to create structural
      elements, i.e., containers (leaf nodes are defined in separate
      groupings)

   o  ietf-bgp-global - groupings with data specific to the global
      context

   o  ietf-bgp-peer-group - groupings with data specific to the peer
      group context

   o  ietf-bgp-neighbor - groupings with data specific to the neighbor
      context

   Additional modules include:

   o  ietf-bgp-types - common type and identity definitions for BGP,
      including BGP policy

   o  ietf-bgp-policy - BGP-specific policy data definitions for use
      with [I-D.ietf-rtgwg-policy-model] (described in more detail
      Section 2.2)

7.  Structure of the YANG modules

   The YANG model can be subdivided between the main module for base
   items, types, policy data, and the RIB module.

7.1.  Main module and submodules for base items

  <CODE BEGINS> file "ietf-bgp-common@2019-02-25.yang"
  submodule ietf-bgp-common {
    yang-version "1.1";



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    belongs-to ietf-bgp {
      prefix "bgp";
    }

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

    organization
      "IETF IDR Working Group";

    contact
      "WG Web:   <http://tools.ietf.org/wg/idr>
       WG List:  <idr@ietf.org>

       Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                Keyur Patel (keyur at arrcus.com),
                Susan Hares (shares at ndzh.com";

    description
      "This sub-module contains common groupings that are common across
       multiple contexts within the BGP module. That is to say that
       they may be application to a subset of global, peer-group or
       neighbor contexts.";

    revision "2019-02-25" {
      description
        "Initial Version";
      reference
        "RFC XXXX, BGP Model for Service Provider Network.";
    }

    grouping neighbor-group-timers-config {
      description
        "Config parameters related to timers associated with the BGP
         peer";

      leaf connect-retry {
        type decimal64 {
          fraction-digits 2;
        }
        default 30;
        description
          "Time interval in seconds between attempts to establish a
           session with the peer.";



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      }

      leaf hold-time {
        type decimal64 {
          fraction-digits 2;
        }
        default 90;
        description
          "Time interval in seconds that a BGP session will be
           considered active in the absence of keepalive or other
           messages from the peer.  The hold-time is typically set to
           3x the keepalive-interval.";
        reference
          "RFC 4271 - A Border Gateway Protocol 4, Sec. 10";
      }

      leaf keepalive-interval {
        type decimal64 {
          fraction-digits 2;
        }
        default 30;
        description
          "Time interval in seconds between transmission of keepalive
           messages to the neighbor.  Typically set to 1/3 the
           hold-time.";
      }

      leaf minimum-advertisement-interval {
        type decimal64 {
          fraction-digits 2;
        }
        default 30;
        description
          "Minimum time which must elapse between subsequent UPDATE
           messages relating to a common set of NLRI being transmitted
           to a peer. This timer is referred to as
           MinRouteAdvertisementIntervalTimer by RFC 4721 and serves to
           reduce the number of UPDATE messages transmitted when a
           particular set of NLRI exhibit instability.";
        reference
          "RFC 4271 - A Border Gateway Protocol 4, Sec 9.2.1.1";
      }
    }

    grouping neighbor-group-config {
      description
        "Neighbor level configuration items.";




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      leaf peer-as {
        type inet:as-number;
        description
          "AS number of the peer.";
      }

      leaf local-as {
        type inet:as-number;
        description
          "The local autonomous system number that is to be used when
           establishing sessions with the remote peer or peer group, if
           this differs from the global BGP router autonomous system
           number.";
      }

      leaf peer-type {
          type bt:peer-type;
          description
            "Explicitly designate the peer or peer group as internal
             (iBGP) or external (eBGP).";
      }

      leaf auth-password {
        type string;
        description
          "Configures an MD5 authentication password for use with
           neighboring devices.";
      }

      leaf remove-private-as {
        // could also make this a container with a flag to enable
        // remove-private and separate option.  here, option implies
        // remove-private is enabled.
        type bt:remove-private-as-option;
        description
          "Remove private AS numbers from updates sent to peers - when
           this leaf is not specified, the AS_PATH attribute should be
           sent to the peer unchanged";
      }

      leaf route-flap-damping {
        type boolean;
        default false;
        description
          "Enable route flap damping.";
      }

      leaf send-community {



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        type bt:community-type;
        default "NONE";
        description
          "Specify which types of community should be sent to the
           neighbor or group. The default is to not send the community
           attribute";
      }

      leaf description {
        type string;
        description
          "An optional textual description (intended primarily for use
           with a peer or group";
      }
    }

    grouping neighbor-group-transport-config {
      description
        "Configuration parameters relating to the transport protocol
         used by the BGP session to the peer";

      leaf tcp-mss {
        type uint16;
        description
          "Sets the max segment size for BGP TCP sessions.";
      }

      leaf mtu-discovery {
        type boolean;
        default false;
        description
          "Turns path mtu discovery for BGP TCP sessions on (true) or
           off (false)";
      }

      leaf passive-mode {
        type boolean;
        default false;
        description
          "Wait for peers to issue requests to open a BGP session,
           rather than initiating sessions from the local router.";
      }

      leaf local-address {
        type union {
          type inet:ip-address;
          type string;
        }



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        //TODO:  the string should be converted to a leafref type
        //to point to an interface when YANG 1.1 is available with
        //leafrefs in union types.
        description
          "Set the local IP (either IPv4 or IPv6) address to use for
           the session when sending BGP update messages.  This may be
           expressed as either an IP address or reference to the name
           of an interface.";
      }
    }

    grouping neighbor-group-error-handling-config {
      description
        "Configuration parameters relating to enhanced error handling
         behaviors for BGP";

      leaf treat-as-withdraw {
        type boolean;
        default "false";
        description
          "Specify whether erroneous UPDATE messages for which the NLRI
           can be extracted are treated as though the NLRI is withdrawn
           - avoiding session reset";
        reference "draft-ietf-idr-error-handling-16";
      }
    }

    grouping graceful-restart-config {
      description
        "Configuration parameters relating to BGP graceful restart.";

      leaf enabled {
        type boolean;
        description
          "Enable or disable the graceful-restart capability.";
      }

      leaf restart-time {
        type uint16 {
          range 0..4096;
        }
        description
          "Estimated time (in seconds) for the local BGP speaker to
           restart a session. This value is advertise in the graceful
           restart BGP capability.  This is a 12-bit value, referred to
           as Restart Time in RFC4724.  Per RFC4724, the suggested
           default value is <= the hold-time value.";
      }



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      leaf stale-routes-time {
        type decimal64 {
          fraction-digits 2;
        }
        description
          "An upper-bound on the time that stale routes will be
           retained by a router after a session is restarted. If an
           End-of-RIB (EOR) marker is received prior to this timer
           expiring stale-routes will be flushed upon its receipt - if
           no EOR is received, then when this timer expires stale paths
           will be purged. This timer is referred to as the
           Selection_Deferral_Timer in RFC4724";
      }

      leaf helper-only {
        type boolean;
        description
          "Enable graceful-restart in helper mode only. When this leaf
           is set, the local system does not retain forwarding its own
           state during a restart, but supports procedures for the
           receiving speaker, as defined in RFC4724.";
      }
    }

    grouping use-multiple-paths-config {
      description
        "Generic configuration options relating to use of multiple
         paths for a referenced AFI-SAFI, group or neighbor";

      leaf enabled {
        type boolean;
        default false;
        description
          "Whether the use of multiple paths for the same NLRI is
           enabled for the neighbor. This value is overridden by any
           more specific configuration value.";
      }
    }

    grouping use-multiple-paths-ebgp-as-options-config {
      description
        "Configuration parameters specific to eBGP multi-path applicable
         to all contexts";

      leaf allow-multiple-as {
       type boolean;
       default "false";
       description



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        "Allow multi-path to use paths from different neighboring ASes.
         The default is to only consider multiple paths from the same
         neighboring AS.";
      }
    }

    grouping global-group-use-multiple-paths {
      description
        "Common grouping used for both global and groups which provides
         configuration and state parameters relating to use of multiple
         paths";

      container use-multiple-paths {
        description
          "Parameters related to the use of multiple paths for the
          same NLRI";

        uses use-multiple-paths-config;

        container ebgp {
          description
            "Multi-Path parameters for eBGP";

          leaf allow-multiple-as {
            type boolean;
            default "false";
            description
              "Allow multi-path to use paths from different neighboring
               ASes.  The default is to only consider multiple paths
               from the same neighboring AS.";
          }

          leaf maximum-paths {
            type uint32;
            default 1;
            description
              "Maximum number of parallel paths to consider when using
               BGP multi-path. The default is use a single path.";
          }
        }

        container ibgp {
          description
            "Multi-Path parameters for iBGP";

          leaf maximum-paths {
            type uint32;
            default 1;



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            description
              "Maximum number of parallel paths to consider when using
               iBGP multi-path. The default is to use a single path";
          }
        }
      }
    }

    grouping route-selection-options {
      description
        "Configuration and state relating to route selection options";

      container route-selection-options {
        description
          "Parameters relating to options for route selection";

        leaf always-compare-med {
          type boolean;
          default "false";
          description
            "Compare multi-exit discriminator (MED) value from
             different ASes when selecting the best route.  The default
             behavior is to only compare MEDs for paths received from
             the same AS.";
        }

        leaf ignore-as-path-length {
          type boolean;
          default "false";
          description
            "Ignore the AS path length when selecting the best path.
             The default is to use the AS path length and prefer paths
             with shorter length.";
        }

        leaf external-compare-router-id {
          type boolean;
          default "true";
          description
            "When comparing similar routes received from external BGP
             peers, use the router-id as a criterion to select the
             active path.";
        }

        leaf advertise-inactive-routes {
          type boolean;
          default "false";
          description



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            "Advertise inactive routes to external peers.  The default
             is to only advertise active routes.";
        }

        leaf enable-aigp {
          type boolean;
          default false;
          description
            "Flag to enable sending / receiving accumulated IGP
             attribute in routing updates";
        }

        leaf ignore-next-hop-igp-metric {
          type boolean;
          default "false";
          description
            "Ignore the IGP metric to the next-hop when calculating BGP
             best-path. The default is to select the route for which
             the metric to the next-hop is lowest";
        }
      }
    }

    grouping state {
      description
        "Grouping containing common counters relating to prefixes and
         paths";

      leaf total-paths {
        type uint32;
        config false;
        description
          "Total number of BGP paths within the context";
      }

      leaf total-prefixes {
        type uint32;
        config false;
        description
          "Total number of BGP prefixes received within the context";
      }
    }
  }
  <CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-common-multiprotocol@2019-02-25.yang"
   submodule ietf-bgp-common-multiprotocol {



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     yang-version "1.1";
     belongs-to ietf-bgp {
       prefix "bgp";
     }

     import ietf-bgp-types {
       prefix bt;
     }
     import ietf-routing-policy {
       prefix rpol;
     }

     include ietf-bgp-common;

     // meta
     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This sub-module contains groupings that are related to support
        for multiple protocols in BGP. The groupings are common across
        multiple contexts.";

     revision "2019-02-25" {
       description
         "Initial Version";
       reference
         "RFC XXX, BGP Model for Service Provider Network.";
     }

     grouping mp-afi-safi-graceful-restart-config {
       description
         "BGP graceful restart parameters that apply on a per-AFI-SAFI
          basis";

       leaf enabled {
         type boolean;
         default false;
         description
           "This leaf indicates whether graceful-restart is enabled for



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            this AFI-SAFI";
       }
     }

     grouping mp-afi-safi-config {
       description
         "Configuration parameters used for all BGP AFI-SAFIs";

       leaf afi-safi-name {
         type identityref {
           base "bt:afi-safi-type";
         }
         description "AFI,SAFI";
       }

       leaf enabled {
         type boolean;
         default false;
         description
           "This leaf indicates whether the IPv4 Unicast AFI,SAFI is
           enabled for the neighbour or group";
       }
     }

     grouping mp-all-afi-safi-list-contents {
       description
         "A common grouping used for contents of the list that is used
         for AFI-SAFI entries";

       // import and export policy included for the afi/safi
       uses rpol:apply-policy-group;

       container ipv4-unicast {
         when "../afi-safi-name = 'bt:IPV4_UNICAST'" {
           description
             "Include this container for IPv4 Unicast specific
              configuration";
         }

         description
           "IPv4 unicast configuration options";

         // include common IPv[46] unicast options
         uses mp-ipv4-ipv6-unicast-common;

         // placeholder for IPv4 unicast  specific configuration
       }




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       container ipv6-unicast {
         when "../afi-safi-name = 'bt:IPV6_UNICAST'" {
           description
             "Include this container for IPv6 Unicast specific
              configuration";
         }

         description
           "IPv6 unicast configuration options";

         // include common IPv[46] unicast options
         uses mp-ipv4-ipv6-unicast-common;

         // placeholder for IPv6 unicast specific configuration
         // options
       }

       container ipv4-labeled-unicast {
         when "../afi-safi-name = 'bt:IPV4_LABELED_UNICAST'" {
           description
             "Include this container for IPv4 Labeled Unicast specific
              configuration";
         }

         description
           "IPv4 Labeled Unicast configuration options";

         uses mp-all-afi-safi-common;

         // placeholder for IPv4 Labeled Unicast specific config
         // options
       }

       container ipv6-labeled-unicast {
         when "../afi-safi-name = 'bt:IPV6_LABELED_UNICAST'" {
           description
             "Include this container for IPv6 Labeled Unicast specific
              configuration";
         }

         description
           "IPv6 Labeled Unicast configuration options";

         uses mp-all-afi-safi-common;

         // placeholder for IPv6 Labeled Unicast specific config
         // options.
       }



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       container l3vpn-ipv4-unicast {
         when "../afi-safi-name = 'bt:L3VPN_IPV4_UNICAST'" {
           description
             "Include this container for IPv4 Unicast L3VPN specific
              configuration";
         }

         description
           "Unicast IPv4 L3VPN configuration options";

         // include common L3VPN configuration options
         uses mp-l3vpn-ipv4-ipv6-unicast-common;

         // placeholder for IPv4 Unicast L3VPN specific config options.
       }

       container l3vpn-ipv6-unicast {
         when "../afi-safi-name = 'bt:L3VPN_IPV6_UNICAST'" {
           description
             "Include this container for unicast IPv6 L3VPN specific
              configuration";
         }

         description
           "Unicast IPv6 L3VPN configuration options";

         // include common L3VPN configuration options
         uses mp-l3vpn-ipv4-ipv6-unicast-common;

         // placeholder for IPv6 Unicast L3VPN specific configuration
         // options
       }

       container l3vpn-ipv4-multicast {
         when "../afi-safi-name = 'bt:L3VPN_IPV4_MULTICAST'" {
           description
             "Include this container for multicast IPv6 L3VPN specific
              configuration";
         }

         description
           "Multicast IPv4 L3VPN configuration options";

         // include common L3VPN multicast options
         uses mp-l3vpn-ipv4-ipv6-multicast-common;

         // placeholder for IPv4 Multicast L3VPN specific configuration
         // options



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       }

       container l3vpn-ipv6-multicast {
         when "../afi-safi-name = 'bt:L3VPN_IPV6_MULTICAST'" {
           description
             "Include this container for multicast IPv6 L3VPN specific
              configuration";
         }
         description
           "Multicast IPv6 L3VPN configuration options";

         // include common L3VPN multicast options
         uses mp-l3vpn-ipv4-ipv6-multicast-common;

         // placeholder for IPv6 Multicast L3VPN specific configuration
         // options
       }

       container l2vpn-vpls {
         when "../afi-safi-name = 'bt:L2VPN_VPLS'" {
           description
             "Include this container for BGP-signalled VPLS specific
              configuration";
         }

         description
           "BGP-signalled VPLS configuration options";

         // include common L2VPN options
         uses mp-l2vpn-common;

         // placeholder for BGP-signalled VPLS specific configuration
         // options
       }

       container l2vpn-evpn {
         when "../afi-safi-name = 'bt:L2VPN_EVPN'" {
           description
             "Include this container for BGP EVPN specific
              configuration";
         }

         description
           "BGP EVPN configuration options";

         // include common L2VPN options
         uses mp-l2vpn-common;




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         // placeholder for BGP EVPN specific configuration options
       }
     }

     // Common groupings across multiple AFI,SAFIs
     grouping mp-all-afi-safi-common {
       description
         "Grouping for configuration common to all AFI,SAFI";

       container prefix-limit {
         description
           "Parameters relating to the prefix limit for the AFI-SAFI";
         leaf max-prefixes {
           type uint32;
           description
             "Maximum number of prefixes that will be accepted from the
              neighbour";
         }
         leaf shutdown-threshold-pct {
           type bt:percentage;
           description
             "Threshold on number of prefixes that can be received from
              a neighbour before generation of warning messages or log
              entries. Expressed as a percentage of max-prefixes";
         }

         leaf restart-timer {
           type decimal64 {
             fraction-digits 2;
           }
           units "seconds";
           description
             "Time interval in seconds after which the BGP session is
              re-established after being torn down due to exceeding the
              max-prefix limit.";
         }
       }
     }

     grouping mp-ipv4-ipv6-unicast-common {
       description
         "Common configuration that is applicable for IPv4 and IPv6
         unicast";

       // include common afi-safi options.
       uses mp-all-afi-safi-common;

       // configuration options that are specific to IPv[46] unicast



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       leaf send-default-route {
         type boolean;
         default "false";
         description
           "If set to true, send the default-route to the neighbour(s)";
       }
     }

     grouping mp-l3vpn-ipv4-ipv6-unicast-common {
       description
         "Common configuration applied across L3VPN for IPv4
          and IPv6";

       // placeholder -- specific configuration options that are generic
       // across IPv[46] unicast address families.
       uses mp-all-afi-safi-common;
     }

     grouping mp-l3vpn-ipv4-ipv6-multicast-common {
       description
         "Common configuration applied across L3VPN for IPv4
         and IPv6";

       // placeholder -- specific configuration options that are
       // generic across IPv[46] multicast address families.
       uses mp-all-afi-safi-common;
     }

     grouping mp-l2vpn-common {
       description
         "Common configuration applied across L2VPN address
         families";

       // placeholder -- specific configuration options that are
       // generic across L2VPN address families
       uses mp-all-afi-safi-common;
     }

     // Config groupings for common groups
     grouping mp-all-afi-safi-common-prefix-limit-config {
       description
         "Configuration parameters relating to prefix-limits for an
         AFI-SAFI";

     }
   }
   <CODE ENDS>




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   <CODE BEGINS> file "ietf-bgp-common-structure@2019-02-25.yang"
   submodule ietf-bgp-common-structure {
     yang-version "1.1";
     belongs-to ietf-bgp {
       prefix "bgp";
     }

     import ietf-bgp-types { prefix bt; }
     import ietf-routing-policy { prefix rpol; }
     include ietf-bgp-common-multiprotocol;
     include ietf-bgp-common;

     // meta
     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This sub-module contains groupings that are common across
        multiple BGP contexts and provide structure around other
        primitive groupings.";


     revision "2019-02-25" {
       description
         "Initial Version";
       reference
         "RFC XXX, BGP Model for Service Provider Network.";
     }

     grouping structure-neighbor-group-logging-options {
       description
         "Structural grouping used to include error handling
          configuration and state for both BGP neighbors and groups";

       container logging-options {
         description
           "Logging options for events related to the BGP neighbor or
           group";

         leaf log-neighbor-state-changes {



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           type boolean;
           default "true";
           description
             "Configure logging of peer state changes.  Default is to
              enable logging of peer state changes.";
         }
       }
     }
     grouping structure-neighbor-group-ebgp-multihop {
       description
         "Structural grouping used to include eBGP multi-hop
          configuration and state for both BGP neighbors and peer
          groups";

       container ebgp-multihop {
         description
           "eBGP multi-hop parameters for the BGPgroup";

         leaf enabled {
           type boolean;
           default "false";
           description
             "When enabled the referenced group or neighbors are
              permitted to be indirectly connected - including cases
              where the TTL can be decremented between the BGP peers";
         }

         leaf multihop-ttl {
           type uint8;
           description
             "Time-to-live value to use when packets are sent to the
              referenced group or neighbors and ebgp-multihop is
              enabled";
         }
       }
     }

     grouping structure-neighbor-group-route-reflector {
       description
         "Structural grouping used to include route reflector
          configuration and state for both BGP neighbors and peer
          groups";

       container route-reflector {
         description
           "Route reflector parameters for the BGPgroup";

         leaf route-reflector-cluster-id {



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           type bt:rr-cluster-id-type;
           description
             "route-reflector cluster id to use when local router is
              configured as a route reflector.  Commonly set at the
              group level, but allows a different cluster id to be set
              for each neighbor.";
         }

         leaf route-reflector-client {
           type boolean;
           default "false";
           description
             "Configure the neighbor as a route reflector client.";
         }
       }
     }

     grouping structure-neighbor-group-as-path-options {
       description
         "Structural grouping used to include AS_PATH manipulation
          configuration and state for both BGP neighbors and peer
          groups";

       container as-path-options {
         description
           "AS_PATH manipulation parameters for the BGP neighbor or
           group";
         leaf allow-own-as {
           type uint8;
           default 0;
           description
             "Specify the number of occurrences of the local BGP
              speaker's AS that can occur within the AS_PATH before it
              is rejected.";
         }

         leaf replace-peer-as {
           type boolean;
           default "false";
           description
             "Replace occurrences of the peer's AS in the AS_PATH with
              the local autonomous system number";
         }
       }
     }

     grouping structure-neighbor-group-add-paths {
       description



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         "Structural grouping used to include ADD-PATHs configuration
          and state for both BGP neighbors and peer groups";

       container add-paths {
         description
           "Parameters relating to the advertisement and receipt of
            multiple paths for a single NLRI (add-paths)";

         leaf receive {
           type boolean;
           default false;
           description
             "Enable ability to receive multiple path advertisements for
              an NLRI from the neighbor or group";
         }

         leaf send-max {
           type uint8;
           description
             "The maximum number of paths to advertise to neighbors for
              a single NLRI";
         }
         leaf eligible-prefix-policy {
           type leafref {
             path "/rpol:routing-policy/rpol:policy-definitions/" +
                  "rpol:policy-definition/rpol:name";
           }
           description
             "A reference to a routing policy which can be used to
              restrict the prefixes for which add-paths is enabled";
         }
       }
     }
   }
   <CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-peer-group@2019-02-25.yang"
   submodule ietf-bgp-peer-group {
     yang-version "1.1";
     belongs-to ietf-bgp {
       prefix "bgp";
     }

     import ietf-routing-policy {
       prefix rpol;
     }




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     // Include the common submodule
     include ietf-bgp-common;
     include ietf-bgp-common-multiprotocol;
     include ietf-bgp-common-structure;

     // meta
     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This sub-module contains groupings that are specific to the
       peer-group context of the OpenConfig BGP module.";

     revision "2019-02-25" {
       description
         "Initial Version";
       reference
         "RFC XXX, BGP Model for Service Provider Network.";
     }

     grouping bgp-peer-group-config {
       description
         "Configuration parameters relating to a base BGP peer group
          that are not also applicable to any other context (e.g.,
          neighbor)";

       leaf peer-group-name {
         type string;
         description
           "Name of the BGP peer-group";
       }

     }

     grouping bgp-peer-group-afi-safi-list {
       description
         "List of address-families associated with the BGP peer-group";

       list afi-safi {
         key "afi-safi-name";



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         description
           "AFI,SAFI configuration available for the
           neighbour or group";

         uses mp-afi-safi-config;

         container graceful-restart {
           description
             "Parameters relating to BGP graceful-restart";

           uses mp-afi-safi-graceful-restart-config;
         }

         uses route-selection-options;
         uses global-group-use-multiple-paths;
         uses mp-all-afi-safi-list-contents;
       }
     }

     grouping bgp-peer-group-base {
       description
         "Parameters related to a BGP group";

       uses bgp-peer-group-config;
       uses neighbor-group-config;
       uses state;

       container timers {
         description
           "Timers related to a BGP peer-group";

         uses neighbor-group-timers-config;
       }

       container transport {
         description
           "Transport session parameters for the BGP peer-group";

         uses neighbor-group-transport-config;
       }

       container error-handling {
         description
           "Error handling parameters used for the BGP peer-group";

         uses neighbor-group-error-handling-config;
       }




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       container graceful-restart {
         description
           "Parameters relating the graceful restart mechanism for BGP";

         uses graceful-restart-config;
       }

       uses structure-neighbor-group-logging-options;
       uses structure-neighbor-group-ebgp-multihop;
       uses structure-neighbor-group-route-reflector;
       uses structure-neighbor-group-as-path-options;
       uses structure-neighbor-group-add-paths;
       uses global-group-use-multiple-paths;
       uses rpol:apply-policy-group;

       container afi-safis {
         description
           "Per-address-family configuration parameters associated with
           thegroup";
         uses bgp-peer-group-afi-safi-list;
       }
     }

     grouping bgp-peer-group-list {
       description
         "The list of BGP peer groups";

       list peer-group {
         key "peer-group-name";
         description
           "List of BGP peer-groups configured on the local system -
            uniquely identified by peer-group name";

         uses bgp-peer-group-base;
       }
     }
   }
   <CODE ENDS>


  <CODE BEGINS> file "ietf-bgp-neighbor@2019-02-25.yang"
  submodule ietf-bgp-neighbor {
    yang-version "1.1";
    belongs-to ietf-bgp {
      prefix "bgp";
    }

    import ietf-routing-policy {



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      prefix rpol;
    }
    import ietf-bgp-types {
      prefix bt;
    }
    import ietf-inet-types {
      prefix inet;
    }
    import ietf-yang-types {
      prefix yang;
    }

    // Include the common submodule
    include ietf-bgp-common;
    include ietf-bgp-common-multiprotocol;
    include ietf-bgp-peer-group;
    include ietf-bgp-common-structure;

    // meta
    organization
      "IETF IDR Working Group";

    contact
      "WG Web:   <http://tools.ietf.org/wg/idr>
       WG List:  <idr@ietf.org>

       Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                Keyur Patel (keyur at arrcus.com),
                Susan Hares (shares at ndzh.com";

    description
      "This sub-module contains groupings that are specific to the
       neighbor context of the OpenConfig BGP module.";

    revision "2019-02-25" {
      description
        "Initial Version";
      reference
        "RFC XXX, BGP Model for Service Provider Network.";
    }

    grouping bgp-neighbor-use-multiple-paths {
      description
        "Multi-path configuration and state applicable to a BGP
         neighbor";

      container use-multiple-paths {
        description



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          "Parameters related to the use of multiple-paths for the same
           NLRI when they are received only from this neighbor";

        uses use-multiple-paths-config;

        container ebgp {
          description
            "Multi-path configuration for eBGP";
          uses use-multiple-paths-ebgp-as-options-config;
        }
      }
    }

    grouping bgp-neighbor-counters-message-types-state {
      description
        "Grouping of BGP message types, included for re-use across
         counters";

      leaf UPDATE {
        type uint64;
        description
          "Number of BGP UPDATE messages announcing, withdrawing or
           modifying paths exchanged.";
      }

      leaf NOTIFICATION {
        type uint64;
        description
          "Number of BGP NOTIFICATION messages indicating an error
           condition has occurred exchanged.";
      }
    }

    grouping bgp-neighbor-afi-safi-list {
      description
        "List of address-families associated with the BGP neighbor";

      list afi-safi {
        key "afi-safi-name";

        description
          "AFI,SAFI configuration available for the neighbour or
           group";

        uses mp-afi-safi-config;

        leaf active {
          type boolean;



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          config false;
          description
            "This value indicates whether a particular AFI-SAFI has
             been successfully negotiated with the peer. An AFI-SAFI may
             be enabled in the current running configuration, but a
             session restart may be required in order to negotiate the
             new capability.";
        }

        container prefixes {
          config false;
          description "Prefix counters for the BGP session";
          leaf received {
            type uint32;
            description
              "The number of prefixes received from the neighbor";
          }

          leaf sent {
            type uint32;
            description
              "The number of prefixes advertised to the neighbor";
          }

          leaf installed {
            type uint32;
            description
              "The number of advertised prefixes installed in the
               Loc-RIB";
          }
        }

        container graceful-restart {
          description
            "Parameters relating to BGP graceful-restart";

          uses mp-afi-safi-graceful-restart-config;

          leaf received {
            type boolean;
            config false;
            description
              "This leaf indicates whether the neighbor advertised the
               ability to support graceful-restart for this AFI-SAFI";
          }

          leaf advertised {
            type boolean;



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            config false;
            description
              "This leaf indicates whether the ability to support
               graceful-restart has been advertised to the peer";
          }
        }

        uses mp-all-afi-safi-list-contents;
        uses bgp-neighbor-use-multiple-paths;
      }
    }

    grouping bgp-neighbor-base {
      description
        "Parameters related to a BGP neighbor";

      leaf peer-group {
        type leafref {
          path "../../../peer-groups/peer-group/peer-group-name";
        }
        description
          "The peer-group with which this neighbor is associated";
      }

      leaf neighbor-address {
        type inet:ip-address;
        description
          "Address of the BGP peer, either in IPv4 or IPv6";
      }

      leaf enabled {
        type boolean;
        default true;
        description
          "Whether the BGP peer is enabled. In cases where the enabled
           leaf is set to false, the local system should not initiate
           connections to the neighbor, and should not respond to TCP
           connections attempts from the neighbor. If the state of the
           BGP session is ESTABLISHED at the time that this leaf is set
           to false, the BGP session should be ceased.";
      }

      uses neighbor-group-config;

      leaf session-state {
        type enumeration {
            enum IDLE {
              description



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                "neighbor is down, and in the Idle state of the FSM";
            }
            enum CONNECT {
              description
                "neighbor is down, and the session is waiting for the
                 underlying transport session to be established";
            }
            enum ACTIVE {
              description
                "neighbor is down, and the local system is awaiting a
                 connection from the remote peer";
            }
            enum OPENSENT {
              description
                "neighbor is in the process of being established.  The
                 local system has sent an OPEN message";
            }
            enum OPENCONFIRM {
              description
                "neighbor is in the process of being established.  The
                 local system is awaiting a NOTIFICATION or KEEPALIVE
                 message";
            }
            enum ESTABLISHED {
              description
                "neighbor is up - the BGP session with the peer is
                 established";
            }
          }
        config false;
        description
          "Operational state of the BGP peer";
      }

      leaf last-established {
        // Was oc-types:timeticks64
        type uint64;
        config false;
        description
          "This timestamp indicates the time that the BGP session last
           transitioned in or out of the Established state.  The value
           is the timestamp in seconds relative to the Unix Epoch (Jan
           1, 1970 00:00:00 UTC).

           The BGP session uptime can be computed by clients as the
           difference between this value and the current time in UTC
           (assuming the session is in the ESTABLISHED state, per the
           session-state leaf).";



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      }

      leaf established-transitions {
        type yang:counter64;
        config false;
        description
          "Number of transitions to the Established state for the
           neighbor session.  This value is analogous to the
           bgpPeerFsmEstablishedTransitions object from the standard
           BGP-4 MIB";
        reference
          "RFC 4273 - Definitions of Managed Objects for BGP-4";
      }

      leaf-list supported-capabilities {
        type identityref {
          base bt:BGP_CAPABILITY;
        }
        config false;
        description
          "BGP capabilities negotiated as supported with the peer";
      }

      container messages {
        config false;
        description
          "Counters for BGP messages sent and received from the
           neighbor";
        container sent {
          description
            "Counters relating to BGP messages sent to the neighbor";
          uses bgp-neighbor-counters-message-types-state;
          }

        container received {
          description
            "Counters for BGP messages received from the neighbor";
          uses bgp-neighbor-counters-message-types-state;
        }
      }

      container queues {
        config false;
        description
          "Counters related to queued messages associated with the BGP
           neighbor";

        leaf input {



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          type uint32;
          description
            "The number of messages received from the peer currently
             queued";
        }

        leaf output {
          type uint32;
          description
            "The number of messages queued to be sent to the peer";
        }
      }

      container timers {
        description
          "Timers related to a BGP neighbor";

        uses neighbor-group-timers-config;

        leaf negotiated-hold-time {
          type decimal64 {
            fraction-digits 2;
          }
          config false;
          description
            "The negotiated hold-time for the BGP session";
        }
      }

      container transport {
        description
          "Transport session parameters for the BGP neighbor";

        uses neighbor-group-transport-config;

        leaf local-port {
          type inet:port-number;
          config false;
          description
            "Local TCP port being used for the TCP session supporting
             the BGP session";
        }

        leaf remote-address {
          type inet:ip-address;
          config false;
          description
            "Remote address to which the BGP session has been



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             established";
        }

        leaf remote-port {
          type inet:port-number;
          config false;
          description
            "Remote port being used by the peer for the TCP session
             supporting the BGP session";
        }
      }

      container error-handling {
        description
          "Error handling parameters used for the BGP neighbor or
           group";
        uses neighbor-group-error-handling-config;

        leaf erroneous-update-messages {
          type uint32;
          config false;
          description
            "The number of BGP UPDATE messages for which the
             treat-as-withdraw mechanism has been applied based on
             erroneous message contents";
        }
      }

      container graceful-restart {
        description
          "Parameters relating the graceful restart mechanism for BGP";

        uses graceful-restart-config;

        leaf peer-restart-time {
          type uint16 {
            range 0..4096;
          }
          config false;
          description
            "The period of time (advertised by the peer) that the peer
             expects a restart of a BGP session to take";
        }

        leaf peer-restarting {
          type boolean;
          config false;
          description



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            "This flag indicates whether the remote neighbor is
             currently in the process of restarting, and hence received
             routes are currently stale";
        }

        leaf local-restarting {
          type boolean;
          config false;
          description
            "This flag indicates whether the local neighbor is
             currently restarting. The flag is unset after all NLRI
             have been advertised to the peer, and the End-of-RIB (EOR)
             marker has been unset";
        }

        leaf mode {
          type enumeration {
            enum HELPER_ONLY {
              description
                "The local router is operating in helper-only mode, and
                 hence will not retain forwarding state during a local
                 session restart, but will do so during a restart of
                 the remote peer";
            }
            enum BILATERAL {
              description
                "The local router is operating in both helper mode, and
                 hence retains forwarding state during a remote
                 restart, and also maintains forwarding state during
                 local session restart";
            }
            enum REMOTE_HELPER {
              description
                "The local system is able to retain routes during
                 restart but the remote system is only able to act as a
                 helper";
            }
          }
          config false;
          description
            "This leaf indicates the mode of operation of BGP graceful
             restart with the peer";
        }
      }

      uses structure-neighbor-group-logging-options;
      uses structure-neighbor-group-ebgp-multihop;
      uses structure-neighbor-group-route-reflector;



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      uses structure-neighbor-group-as-path-options;
      uses structure-neighbor-group-add-paths;
      uses bgp-neighbor-use-multiple-paths;
      uses rpol:apply-policy-group;

      container afi-safis {
        description
          "Per-address-family configuration parameters associated with
          the neighbor";
        uses bgp-neighbor-afi-safi-list;
      }
    }

    grouping bgp-neighbor-list {
      description
        "The list of BGP neighbors";

      list neighbor {
        key "neighbor-address";
        description
          "List of BGP neighbors configured on the local system,
          uniquely identified by peer IPv[46] address";

        uses bgp-neighbor-base;
      }
    }
  }
  <CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-global@2019-02-25.yang"
   submodule ietf-bgp-global {
     yang-version "1.1";
     belongs-to ietf-bgp {
       prefix bgp;
     }

     import ietf-inet-types {
       prefix inet;
     }
     import ietf-yang-types {
       prefix yang;
     }

     include ietf-bgp-common;
     include ietf-bgp-common-multiprotocol;

     organization



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       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This sub-module contains groupings that are specific to the
        global context of the BGP module";

     revision "2019-02-25" {
       description
         "Initial Version";
       reference
         "RFC XXX, BGP Model for Service Provider Network.";
     }

     grouping bgp-global-config {
       description
         "Global configuration options for the BGP router.";

       leaf as {
         type inet:as-number;
         mandatory true;
         description
           "Local autonomous system number of the router.  Uses
           the 32-bit as-number type from the model in RFC 6991.";
       }

       leaf router-id {
         type yang:dotted-quad;
         description
           "Router id of the router - an unsigned 32-bit integer
           expressed in dotted quad notation.";
         reference
           "RFC4271 - A Border Gateway Protocol 4 (BGP-4),
           Section 4.2";
       }
     }

     grouping bgp-global-state {
       description
         "Operational state parameters for the BGP neighbor";




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       uses state;
     }

     grouping bgp-global-default-route-distance-config {
       description
         "Configuration options relating to the administrative distance
         (or preference) assigned to routes received from different
         sources (external, internal, and local).";

       leaf external-route-distance {
         type uint8 {
           range "1..255";
         }
         description
           "Administrative distance for routes learned from external
           BGP (eBGP).";
       }
       leaf internal-route-distance {
         type uint8 {
           range "1..255";
         }
         description
           "Administrative distance for routes learned from internal
           BGP (iBGP).";
       }
     }

     grouping bgp-global-confederation-config {
       description
         "Configuration options specifying parameters when the local
         router is within an autonomous system which is part of a BGP
         confederation.";

       leaf enabled {
         type boolean;
         description
           "When this leaf is set to true it indicates that
           the local-AS is part of a BGP confederation";
       }

       leaf identifier {
         type inet:as-number;
         description
           "Confederation identifier for the autonomous system.";
       }

       leaf-list member-as {
         type inet:as-number;



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         description
           "Remote autonomous systems that are to be treated
           as part of the local confederation.";
       }
     }

     grouping bgp-global-afi-safi-list {
       description
         "List of address-families associated with the BGP instance";

       list afi-safi {
         key "afi-safi-name";

         description
           "AFI,SAFI configuration available for the
           neighbour or group";

         uses mp-afi-safi-config;
         uses state;

         container graceful-restart {
           description
             "Parameters relating to BGP graceful-restart";

           uses mp-afi-safi-graceful-restart-config;
         }

         uses route-selection-options;
         uses global-group-use-multiple-paths;
         uses mp-all-afi-safi-list-contents;
       }
     }

     // Structural groupings
     grouping bgp-global-base {
       description
         "Global configuration parameters for the BGP router";

       uses bgp-global-config;
       uses bgp-global-state;

       container default-route-distance {
         description
           "Administrative distance (or preference) assigned to
           routes received from different sources
           (external, internal, and local).";

         uses bgp-global-default-route-distance-config;



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       }

       container confederation {
         description
           "Parameters indicating whether the local system acts as part
           of a BGP confederation";

         uses bgp-global-confederation-config;
       }

       container graceful-restart {
         description
           "Parameters relating the graceful restart mechanism for BGP";
         uses graceful-restart-config;
       }

       uses global-group-use-multiple-paths;
       uses route-selection-options;

       container afi-safis {
         description
           "Address family specific configuration";
         uses bgp-global-afi-safi-list;
       }
     }

   }
   <CODE ENDS>


7.2.  BGP types

   <CODE BEGINS> file "ietf-bgp-types@2019-02-25.yang"
   module ietf-bgp-types {
     yang-version "1.1";
     namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-types";

     prefix "bt";

     import ietf-inet-types {
       prefix inet;
     }

     // meta
     organization
       "IETF IDR Working Group";

     contact



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       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This module contains general data definitions for use in BGP
       policy. It can be imported by modules that make use of BGP
       attributes";

     revision "2019-02-25" {
       description
         "Initial Version";
       reference
         "RFC XXX, BGP Model for Service Provider Network.";
     }

     identity BGP_CAPABILITY {
       description "Base identity for a BGP capability";
     }

     identity MPBGP {
       base BGP_CAPABILITY;
       description
         "Multi-protocol extensions to BGP";
       reference "RFC2858";
     }

     identity ROUTE_REFRESH {
       base BGP_CAPABILITY;
       description
         "The BGP route-refresh functionality";
       reference "RFC2918";
     }

     identity ASN32 {
       base BGP_CAPABILITY;
       description
         "4-byte (32-bit) AS number functionality";
       reference "RFC6793";
     }

     identity GRACEFUL_RESTART {
       base BGP_CAPABILITY;
       description
         "Graceful restart functionality";



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       reference "RFC4724";
     }

     identity ADD_PATHS {
       base BGP_CAPABILITY;
       description
         "BGP add-paths";
       reference "draft-ietf-idr-add-paths";
     }

     identity afi-safi-type {
       description
         "Base identity type for AFI,SAFI tuples for BGP-4";
       reference "RFC4760 - multi-protocol extensions for BGP-4";
     }

     identity ipv4-unicast {
       base afi-safi-type;
       description
         "IPv4 unicast (AFI,SAFI = 1,1)";
       reference "RFC4760";
     }

     identity ipv6-unicast {
       base afi-safi-type;
       description
         "IPv6 unicast (AFI,SAFI = 2,1)";
       reference "RFC4760";
     }

     identity IPV4_LABELED_UNICAST {
       base afi-safi-type;
       description
         "Labeled IPv4 unicast (AFI,SAFI = 1,4)";
       reference "RFC3107";
     }

     identity IPV6_LABELED_UNICAST {
       base afi-safi-type;
       description
         "Labeled IPv6 unicast (AFI,SAFI = 2,4)";
       reference "RFC3107";
     }

     identity L3VPN_IPV4_UNICAST {
       base afi-safi-type;
       description
         "Unicast IPv4 MPLS L3VPN (AFI,SAFI = 1,128)";



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       reference "RFC4364";
     }

     identity L3VPN_IPV6_UNICAST {
       base afi-safi-type;
       description
         "Unicast IPv6 MPLS L3VPN (AFI,SAFI = 2,128)";
       reference "RFC4659";
     }

     identity L3VPN_IPV4_MULTICAST {
       base afi-safi-type;
       description
         "Multicast IPv4 MPLS L3VPN (AFI,SAFI = 1,129)";
       reference "RFC6514";
     }

     identity L3VPN_IPV6_MULTICAST {
       base afi-safi-type;
       description
         "Multicast IPv6 MPLS L3VPN (AFI,SAFI = 2,129)";
       reference "RFC6514";
     }

     identity L2VPN_VPLS {
       base afi-safi-type;
       description
         "BGP-signalled VPLS (AFI,SAFI = 25,65)";
       reference "RFC4761";
     }

     identity L2VPN_EVPN {
       base afi-safi-type;
       description
         "BGP MPLS Based Ethernet VPN (AFI,SAFI = 25,70)";
     }

     identity BGP_WELL_KNOWN_STD_COMMUNITY {
       description
         "Reserved communities within the standard community space
         defined by RFC1997. These communities must fall within the
         range 0x00000000 to 0xFFFFFFFF";
       reference "RFC1997";
     }

     identity NO_EXPORT {
       base BGP_WELL_KNOWN_STD_COMMUNITY;
       description



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         "Do not export NLRI received carrying this community outside
         the bounds of this autonomous system, or this confederation if
         the local autonomous system is a confederation member AS. This
         community has a value of 0xFFFFFF01.";
       reference "RFC1997";
     }

     identity NO_ADVERTISE {
       base BGP_WELL_KNOWN_STD_COMMUNITY;
       description
         "All NLRI received carrying this community must not be
         advertised to other BGP peers. This community has a value of
         0xFFFFFF02.";
       reference "RFC1997";
     }

     identity NO_EXPORT_SUBCONFED {
       base BGP_WELL_KNOWN_STD_COMMUNITY;
       description
         "All NLRI received carrying this community must not be
         advertised to external BGP peers - including over confederation
         sub-AS boundaries. This community has a value of 0xFFFFFF03.";
       reference "RFC1997";
     }

     identity NOPEER {
       base BGP_WELL_KNOWN_STD_COMMUNITY;
       description
         "An autonomous system receiving NLRI tagged with this community
         is advised not to re-advertise the NLRI to external bi-lateral
         peer autonomous systems. An AS may also filter received NLRI
         from bilateral peer sessions when they are tagged with this
         community value";
       reference "RFC3765";
     }

     identity as-path-segment-type {
       description
         "Base AS Path Segment Type. In [BGP-4], the path segment type
          is a 1-octet field with the following values defined.";
       reference
         "RFC 5065";
     }

     identity as-set {
       base as-path-segment-type;
       description
         "Unordered set of autonomous systems that a route in the UPDATE



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          message has traversed.";
       reference
         "RFC 5065";
     }

     identity as-sequence {
       base as-path-segment-type;
       description
         "Ordered set of autonomous systems that a route in the UPDATE
          message has traversed.";
       reference
         "RFC 5065";
     }

     identity as-confed-sequence {
       base as-path-segment-type;
       description
         "Ordered set of Member Autonomous Systems in the local
          confederation that the UPDATE message has traversed.";
       reference
         "RFC 5065";
     }

     identity as-confed-set {
       base as-path-segment-type;
       description
         "Unordered set of Member Autonomous Systems in the local
          confederation that the UPDATE message has traversed.";
       reference
         "RFC 5065";
     }

     typedef bgp-session-direction {
       type enumeration {
         enum INBOUND {
           description
             "Refers to all NLRI received from the BGP peer";
         }
         enum OUTBOUND {
           description
             "Refers to all NLRI advertised to the BGP peer";
         }
       }
       description
         "Type to describe the direction of NLRI transmission";
     }

     typedef bgp-well-known-community-type {



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       type identityref {
         base BGP_WELL_KNOWN_STD_COMMUNITY;
       }
       description
         "Type definition for well-known IETF community attribute
         values";
       reference
         "IANA Border Gateway Protocol (BGP) Well Known Communities";
     }


     typedef bgp-std-community-type {
       // TODO: further refine restrictions and allowed patterns
       // 4-octet value:
       //  <as number> 2 octets
       //  <community value> 2 octets
       type union {
         type uint32 {
         // per RFC 1997, 0x00000000 - 0x0000FFFF and 0xFFFF0000 -
         // 0xFFFFFFFF are reserved
           range "65536..4294901759"; // 0x00010000..0xFFFEFFFF
         }
         type string {
           pattern '([0-9]+:[0-9]+)';
         }
       }
       description
         "Type definition for standard community attributes";
       reference "RFC 1997 - BGP Communities Attribute";
     }

     typedef bgp-ext-community-type {
       // TODO: needs more work to make this more precise given the
       // variability of extended community attribute specifications
       // 8-octet value:
       //  <type> 2 octects
       //  <value> 6 octets

       type union {
         type string {
           // Type 1: 2-octet global and 4-octet local
           //         (AS number)        (Integer)
           pattern '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'            +
                   '[1-9][0-9]{1,4}|[0-9]):'                          +
                   '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|' +
                   '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[1-9])';
         }
         type string {



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           // Type 2: 4-octet global and 2-octet local
           //         (ipv4-address)     (integer)
           pattern '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|'      +
                   '25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|'     +
                   '2[0-4][0-9]|25[0-5]):'                            +
                   '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'            +
                   '[1-9][0-9]{1,4}|[0-9])';
         }
         type string {
           // route-target with Type 1
           // route-target:(ASN):(local-part)
           pattern 'route\-target:(6[0-5][0-5][0-3][0-5]|'            +
                   '[1-5][0-9]{4}|[1-9][0-9]{1,4}|[0-9]):'            +
                   '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|' +
                   '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[1-9])';
         }
         type string {
           // route-target with Type 2
           // route-target:(IPv4):(local-part)
           pattern 'route\-target:' +
                   '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|'      +
                   '25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|'     +
                   '2[0-4][0-9]|25[0-5]):'                            +
                   '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'            +
                   '[1-9][0-9]{1,4}|[0-9])';
         }
         type string {
           // route-origin with Type 1
           pattern 'route\-origin:(6[0-5][0-5][0-3][0-5]|'            +
                   '[1-5][0-9]{4}|[1-9][0-9]{1,4}|[0-9]):'            +
                   '(4[0-2][0-9][0-4][0-9][0-6][0-7][0-2][0-9][0-6]|' +
                   '[1-3][0-9]{9}|[1-9]([0-9]{1,7})?[0-9]|[1-9])';
         }
         type string {
           // route-origin with Type 2
           pattern 'route\-origin:' +
                   '(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|'      +
                   '25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9][0-9]|'     +
                   '2[0-4][0-9]|25[0-5]):'                            +
                   '(6[0-5][0-5][0-3][0-5]|[1-5][0-9]{4}|'            +
                   '[1-9][0-9]{1,4}|[0-9])';
         }
       }
       description
         "Type definition for extended community attributes";
       reference "RFC 4360 - BGP Extended Communities Attribute";
     }




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     typedef bgp-community-regexp-type {
       // TODO: needs more work to decide what format these regexps can
       // take.
       //type oc-types:std-regexp;
       type string;
       description
         "Type definition for communities specified as regular
         expression patterns";
     }

     typedef bgp-origin-attr-type {
       type enumeration {
         enum IGP {
           description "Origin of the NLRI is internal";
         }
         enum EGP {
           description "Origin of the NLRI is EGP";
         }
         enum INCOMPLETE {
           description "Origin of the NLRI is neither IGP or EGP";
         }
       }
       description
         "Type definition for standard BGP origin attribute";
       reference "RFC 4271 - A Border Gateway Protocol 4 (BGP-4),
         Sec 4.3";
     }

     typedef peer-type {
       type enumeration {
         enum INTERNAL {
           description "internal (iBGP) peer";
         }
         enum EXTERNAL {
           description "external (eBGP) peer";
         }
       }
       description
         "labels a peer or peer group as explicitly internal or
         external";
     }

     identity REMOVE_PRIVATE_AS_OPTION {
       description
         "Base identity for options for removing private autonomous
         system numbers from the AS_PATH attribute";
     }




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     identity PRIVATE_AS_REMOVE_ALL {
       base REMOVE_PRIVATE_AS_OPTION;
       description
         "Strip all private autonomous system numbers from the AS_PATH.
         This action is performed regardless of the other content of the
         AS_PATH attribute, and for all instances of private AS numbers
         within that attribute.";
     }

     identity PRIVATE_AS_REPLACE_ALL {
       base REMOVE_PRIVATE_AS_OPTION;
       description
         "Replace all instances of private autonomous system numbers in
         the AS_PATH with the local BGP speaker's autonomous system
         number. This action is performed regardless of the other
         content of the AS_PATH attribute, and for all instances of
         private AS number within that attribute.";
     }

     typedef remove-private-as-option {
       type identityref {
         base REMOVE_PRIVATE_AS_OPTION;
       }
       description
         "set of options for configuring how private AS path numbers
         are removed from advertisements";
     }

     typedef percentage {
       type uint8 {
         range "0..100";
       }
       description
         "Integer indicating a percentage value";
     }

     typedef rr-cluster-id-type {
       type union {
         type uint32;
         type inet:ipv4-address;
       }
       description
         "union type for route reflector cluster ids:
         option 1: 4-byte number
         option 2: IP address";
     }

     typedef community-type {



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       type enumeration {
         enum STANDARD {
           description "send only standard communities";
         }
         enum EXTENDED {
           description "send only extended communities";
         }
         enum BOTH {
           description "send both standard and extended communities";
         }
         enum NONE {
           description "do not send any community attribute";
         }
       }
       description
         "type describing variations of community attributes:
         STANDARD: standard BGP community [rfc1997]
         EXTENDED: extended BGP community [rfc4360]
         BOTH: both standard and extended community";
     }
   }
   <CODE ENDS>


7.3.  BGP policy data

     <CODE BEGINS> file "ietf-bgp-policy@2019-02-25.yang"
 module ietf-bgp-policy {
   yang-version "1.1";
   namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-policy";
   prefix "bp";

   // import some basic types
   import ietf-inet-types {
     prefix inet;
   }
   import ietf-routing-policy {
     prefix rpol;
   }
   import ietf-bgp-types {
     prefix bt;
   }

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

   organization



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     "IETF IDR Working Group";

   contact
     "WG Web:   <http://tools.ietf.org/wg/idr>
      WG List:  <idr@ietf.org>

      Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
               Keyur Patel (keyur at arrcus.com),
               Susan Hares (shares at ndzh.com";

   description
     "This module contains data definitions for BGP routing policy.
     It augments the base routing-policy module with BGP-specific
     options for conditions and actions.";

   revision "2019-02-25" {
     description
       "Initial Version";
     reference
       "RFC XXX, BGP Model for Service Provider Network.";
   }

   // typedef statements

   typedef bgp-set-community-option-type {
     type enumeration {
       enum ADD {
         description
           "add the specified communities to the existing
           community attribute";
       }
       enum REMOVE {
         description
           "remove the specified communities from the
           existing community attribute";
       }
       enum REPLACE {
         description
           "replace the existing community attribute with
           the specified communities. If an empty set is
           specified, this removes the community attribute
           from the route.";
       }
     }
     description
       "Type definition for options when setting the community
       attribute in a policy action";
   }



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   typedef bgp-next-hop-type {
     type union {
       type inet:ip-address-no-zone;
       type enumeration {
         enum SELF {
           description "special designation for local router's own
           address, i.e., next-hop-self";
         }
       }
     }
     description
       "type definition for specifying next-hop in policy actions";
   }

   typedef bgp-set-med-type {
     type union {
       type uint32;
       type string {
         pattern "^[+-][0-9]+";
       }
       type enumeration {
         enum IGP {
           description "set the MED value to the IGP cost toward the
           next hop for the route";
         }
       }
     }
     description
       "Type definition for specifying how the BGP MED can
       be set in BGP policy actions. The three choices are to set
       the MED directly, increment/decrement using +/- notation,
       and setting it to the IGP cost (predefined value).";
   }

   // augment statements

   augment "/rpol:routing-policy/rpol:defined-sets" {
     description
       "Adds BGP defined sets container to routing policy model.";

     container bgp-defined-sets {
       description
         "BGP-related set definitions for policy match conditions";

       container community-sets {
         description
           "Enclosing container for list of defined BGP community sets";




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         list community-set {
           key "community-set-name";
           description
             "List of defined BGP community sets";

           leaf community-set-name {
             type string;
             mandatory true;
             description
               "name / label of the community set -- this is used to
              reference the set in match conditions";
           }

           leaf-list community-member {
             type union {
               type bt:bgp-std-community-type;
               type bt:bgp-community-regexp-type;
               type bt:bgp-well-known-community-type;
             }
             description
               "members of the community set";
           }
         }
       }

       container ext-community-sets {
         description
           "Enclosing container for list of extended BGP community
         sets";
         list ext-community-set {
           key "ext-community-set-name";
           description
             "List of defined extended BGP community sets";

           leaf ext-community-set-name {
             type string;
             description
               "name / label of the extended community set -- this is
              used to reference the set in match conditions";
           }

           leaf-list ext-community-member {
             type union {
               type rt-types:route-target;
               type bt:bgp-community-regexp-type;
             }
             description
               "members of the extended community set";



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           }
         }
       }

       container as-path-sets {
         description
           "Enclosing container for list of define AS path sets";

         list as-path-set {
           key "as-path-set-name";
           description
             "List of defined AS path sets";

           leaf as-path-set-name {
             type string;
             description
               "name of the AS path set -- this is used to reference the
                set in match conditions";
           }

           leaf-list as-path-set-member {
             // TODO: need to refine typedef for AS path expressions
             type string;
             description
               "AS path expression -- list of ASes in the set";
           }
         }
       }
     }
   }

   grouping as-path-prepend-top {
     description
       "Top-level grouping for the AS path prepend action";


   }

   grouping set-community-action-common {
     description
       "Common leaves for set-community and set-ext-community
       actions";

     leaf method {
       type enumeration {
         enum INLINE {
           description
             "The extended communities are specified inline as a



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             list";
         }
         enum REFERENCE {
           description
             "The extended communities are specified by referencing a
             defined ext-community set";
         }
       }
       description
         "Indicates the method used to specify the extended
         communities for the set-ext-community action";
     }

     leaf options {
       type bgp-set-community-option-type;
       description
         "Options for modifying the community attribute with
         the specified values.  These options apply to both
         methods of setting the community attribute.";
     }
   }

   augment "/rpol:routing-policy/rpol:policy-definitions/" +
     "rpol:policy-definition/rpol:statements/rpol:statement/" +
     "rpol:conditions" {
     description
       "BGP policy conditions added to routing policy module";

     container bgp-conditions {
       description
         "Top-level container for BGP specific policy conditions ";

       leaf med-eq {
         type uint32;
         description
           "Condition to check if the received MED value is equal to
            the specified value";
       }

       leaf origin-eq {
         type bt:bgp-origin-attr-type;
         description
           "Condition to check if the route origin is equal to the
            specified value";
       }

       leaf-list next-hop-in {
         type inet:ip-address-no-zone;



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         description
           "List of next hop addresses to check for in the route
            update";
       }

       leaf-list afi-safi-in {
         type identityref {
           base bt:afi-safi-type;
         }
         description
           "List of address families which the NLRI may be within";
       }

       leaf local-pref-eq {
         type uint32;
         // TODO: add support for other comparisons if needed
         description
           "Condition to check if the local pref attribute is equal to
            the specified value";
       }

       leaf route-type {
         // TODO: verify extent of vendor support for this comparison
         type enumeration {
           enum INTERNAL {
             description "route type is internal";
           }
           enum EXTERNAL {
             description "route type is external";
           }
         }
         description
           "Condition to check the route type in the route update";
       }

       container community-count {
         description
           "Value and comparison operations for conditions based on the
            number of communities in the route update";
       }

       container as-path-length {
         description
           "Value and comparison operations for conditions based on the
            length of the AS path in the route update";
       }

       container match-community-set {



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         description
           "Top-level container for match conditions on communities.
         Match a referenced community-set according to the logic
         defined in the match-set-options leaf";

         leaf community-set {
           type leafref {
             path
               "/rpol:routing-policy/rpol:defined-sets/" +
               "bp:bgp-defined-sets/bp:community-sets/" +
               "bp:community-set/bp:community-set-name";
           }
           description
             "References a defined community set";
         }

         uses rpol:match-set-options-group;
       }

       container match-ext-community-set {
         description
           "Match a referenced extended community-set according to the
         logic defined in the match-set-options leaf";

         leaf ext-community-set {
           type leafref {
             path
               "/rpol:routing-policy/rpol:defined-sets/" +
               "bp:bgp-defined-sets/bp:ext-community-sets/" +
               "bp:ext-community-set/" +
               "bp:ext-community-set-name";
           }
           description "References a defined extended community set";
         }

         uses rpol:match-set-options-group;
       }

       container match-as-path-set {
         description
           "Match a referenced as-path set according to the logic
          defined in the match-set-options leaf";

         leaf as-path-set {
           type leafref {
             path "/rpol:routing-policy/rpol:defined-sets/" +
               "bp:bgp-defined-sets/bp:as-path-sets/" +
               "bp:as-path-set/bp:as-path-set-name";



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           }
           description
             "References a defined AS path set";
         }
         uses rpol:match-set-options-group;
       }
     }
   }

   augment "/rpol:routing-policy/rpol:policy-definitions/" +
     "rpol:policy-definition/rpol:statements/rpol:statement/" +
     "rpol:actions" {
     description
       "BGP policy actions added to routing policy module.";

     container bgp-actions {
       description
         "Top-level container for BGP-specific actions";

       leaf set-route-origin {
         type bt:bgp-origin-attr-type;
         description
           "set the origin attribute to the specified value";
       }

       leaf set-local-pref {
         type uint32;
         description
           "set the local pref attribute on the route update";
       }

       leaf set-next-hop {
         type bgp-next-hop-type;
         description
           "set the next-hop attribute in the route update";
       }

       leaf set-med {
         type bgp-set-med-type;
         description
           "set the med metric attribute in the route update";
       }

       container set-as-path-prepend {
         description
           "action to prepend local AS number to the AS-path a
            specified number of times";




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         leaf repeat-n {
           type uint8 {
             range 1..max;
           }
           description
             "Number of times to prepend the local AS number to the AS
              path.  The value should be between 1 and the maximum
              supported by the implementation.";
         }
       }

       container set-community {
         description
           "Action to set the community attributes of the route, along
            with options to modify how the community is modified.
            Communities may be set using an inline list OR
            reference to an existing defined set (not both).";

         uses set-community-action-common;
         container inline {
           when "../config/method=INLINE" {
             description
               "Active only when the set-community method is INLINE";
           }
           description
             "Set the community values for the action inline with
              a list.";

           leaf-list communities {
             type union {
               type bt:bgp-std-community-type;
               type bt:bgp-well-known-community-type;
             }
             description
               "Set the community values for the update inline with a
                list.";
           }
         }

         container reference {
           when "../config/method=REFERENCE" {
             description
               "Active only when the set-community method is REFERENCE";
           }
           description
             "Provide a reference to a defined community set for the
              set-community action";




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           leaf community-set-ref {
             type leafref {
               path "/rpol:routing-policy/rpol:defined-sets/" +
                 "bp:bgp-defined-sets/" +
                 "bp:community-sets/bp:community-set/" +
                 "bp:community-set-name";
             }
             description
               "References a defined community set by name";
           }
         }
       }

       container set-ext-community {
         description
           "Action to set the extended community attributes of the
            route, along with options to modify how the community is
            modified. Extended communities may be set using an inline
            list OR a reference to an existing defined set (but not
            both).";

         uses set-community-action-common;
         container inline {
           when "../config/method=INLINE" {
             description
               "Active only when the set-community method is INLINE";
           }
           description
             "Set the extended community values for the action inline
              with a list.";

           leaf-list communities {
             type union {
               type rt-types:route-target;
               type bt:bgp-well-known-community-type;
             }
             description
               "Set the extended community values for the update inline
                with a list.";
           }
         }

         container reference {
           when "../config/method=REFERENCE" {
             description
               "Active only when the set-community method is REFERENCE";
           }
           description



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             "Provide a reference to an extended community set for the
              set-ext-community action";

           leaf ext-community-set-ref {
             type leafref {
               path
                 "/rpol:routing-policy/rpol:defined-sets/" +
                 "bp:bgp-defined-sets/bp:ext-community-sets/" +
                 "bp:ext-community-set/" +
                 "bp:ext-community-set-name";
             }
             description
               "References a defined extended community set by name";
           }
         }
       }
     }
   }

   // rpc statements

   // notification statements
 }
     <CODE ENDS>

7.4.  RIB modules

  <CODE BEGINS> file "ietf-bgp-rib@2019-02-25.yang"
  module ietf-bgp-rib {
    yang-version "1.1";
    namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-rib";
    prefix "br";

    /*
     * Import and Include
     */
    import ietf-routing {
      prefix "rt";
      reference
        "RFC 8349: YANG Route Management.";
    }

    import ietf-bgp-types {
      prefix "bt";
      reference
        "RFC XXXX: BGP YANG Model for Service Provider Networks.";
    }




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    include ietf-bgp-rib-tables;
    include ietf-bgp-rib-shared-attributes;

    // groupings of attributes in three categories:
    //  - shared across multiple routes
    //  - common to LOC-RIB and Adj-RIB, but not shared across routes
    //  - specific to LOC-RIB or Adj-RIB
    include ietf-bgp-rib-attributes;

    // groupings of annotations for each route or table
    include ietf-bgp-rib-table-attributes;

    organization
      "IETF IDR Working Group";

    contact
      "WG Web:   <http://tools.ietf.org/wg/idr>
       WG List:  <idr@ietf.org>

       Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                Keyur Patel (keyur at arrcus.com),
                Susan Hares (shares at ndzh.com";

    description
      "Defines a data model for representing BGP routing table (RIB)
       contents.  The model supports 5 logical RIBs per address family:

       loc-rib: This is the main BGP routing table for the local routing
       instance, containing best-path selections for each prefix. The
       loc-rib table may contain multiple routes for a given prefix,
       with an attribute to indicate which was selected as the best
       path.  Note that multiple paths may be used or advertised even if
       only one path is marked as best, e.g., when using BGP
       add-paths.  An implementation may choose to mark multiple
       paths in the RIB as best path by setting the flag to true for
       multiple entries.

       adj-rib-in-pre: This is a per-neighbor table containing the NLRI
       updates received from the neighbor before any local input policy
       rules or filters have been applied.  This can be considered the
       'raw' updates from a given neighbor.

       adj-rib-in-post: This is a per-neighbor table containing the
       routes received from the neighbor that are eligible for
       best-path selection after local input policy rules have been
       applied.

       adj-rib-out-pre: This is a per-neighbor table containing routes



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       eligible for sending (advertising) to the neighbor before output
       policy rules have been applied.

       adj-rib-out-post: This is a per-neighbor table containing routes
       eligible for sending (advertising) to the neighbor after output
       policy rules have been applied.";

    revision "2019-02-25" {
      description
        "Initial Version";
      reference
        "RFC XXXX, BGP YANG Model for Service Provider Network.";
    }

    augment "/rt:routing/rt:ribs" {
      when "derived-from-or-self(../rt:control-plane-protocols/" +
        "rt:control-plane-protocol/rt:type, 'bgp')" {
        description
          "This augmentation is only valid for routes whose control
           plane protocol is BGP.";
      }
      description
        "Support for RIBS.";

      container rib {
        config false;
        description
          "Top level container for BGP RIB";

        uses attribute-sets;
        uses community-sets;
        uses ext-community-sets;

        container afi-safis {
          config false;
          description
            "Enclosing container for address family list";

          list afi-safi {
            key "afi-safi-name";
            description
              "List of afi-safi types.";

            leaf afi-safi-name {
              type identityref {
                base bt:afi-safi-type;
              }
              description "AFI,SAFI name.";



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            }

            container ipv4-unicast {
              when "../afi-safi-name = 'bt:ipv4-unicast'" {
                description
                  "Include this container for IPv4 unicast RIB";
              }
              description
                "Routing tables for IPv4 unicast -- active when the
               afi-safi name is ipv4-unicast";

              uses ipv4-loc-rib;
              uses ipv4-adj-rib;
            }

            container ipv6-unicast {
              when "../afi-safi-name = 'bt:ipv6-unicast'" {
                description
                  "Include this container for IPv6 unicast RIB";
              }
              description
                "Routing tables for IPv6 unicast -- active when the
               afi-safi name is ipv6-unicast";

              uses ipv6-loc-rib;
              uses ipv6-adj-rib;
            }

            container ipv4-srte-policy {
              when "../afi-safi-name = 'bt:srte-policy-ipv4'" {
                description
                  "Include this container only for the IPv4 AFI, SR-TE
                 Policy SAFI.";
              }
              description
                "Routing tables for the IPv4 Unicast, SR-TE Policy
               SAFI.";

              uses ipvX-srte-policy-locrib;
              uses ipvX-srte-policy-adjrib;
            }

            container ipv6-srte-policy {
              when "../afi-safi-name = 'bt:srte-policy-ipv6'" {
                description
                  "Include this container only for the IPv6 AFI,
                 SR-TE Policy SAFI.";
              }



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              description
                "Routing tables for the IPv6 Unicast, SR-TE Policy
               SAFI.";

              uses ipvX-srte-policy-locrib;
              uses ipvX-srte-policy-adjrib;
            }
          }
        }
      }
    }
  }
  <CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-rib-ext@2019-02-25.yang"
   module ietf-bgp-rib-ext {
     yang-version "1.1";
     namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-rib-ext";

     prefix "bre";

     import ietf-routing {
       prefix "rt";
       reference
         "RFC 8349: YANG Routing Management.";
     }
     import ietf-bgp-rib {
       prefix bgprib;
     }
     import ietf-bgp-rib-types {
       prefix bgpribt;
     }

     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "Defines additional data nodes for the OpenConfig BGP RIB model.
        These items reflect extensions that are desirable features but



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        are not currently supported in a majority of BGP
        implementations.";

     revision "2019-02-25" {
       description
         "Initial Revision.";
       reference
         "RFC XXXX: BGP YANG Model for Service Providers.";
     }

     grouping rib-ext-route-annotations {
       description
         "Extended annotations for routes in the routing tables";

       leaf reject-reason {
         type union {
           type identityref {
             base bgpribt:bgp-not-selected-bestpath;
           }
           type identityref {
             base bgpribt:bgp-not-selected-policy;
           }
         }
         description
           "Indicates the reason the route is not used, either due to
           policy filtering or bestpath selection";
       }
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv4-unicast/bgprib:loc-rib/" +
       "bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to the Loc-RIB for IPv4";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv6-unicast/bgprib:loc-rib/" +
       "bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to the Loc-RIB for IPv6";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +



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       "bgprib:afi-safi/bgprib:ipv4-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-in-pre/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv4";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv4-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-in-post/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv4";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv4-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-out-pre/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv4";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv4-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-out-post/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv4";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv6-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-in-pre/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv6";

         uses rib-ext-route-annotations;
     }



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     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv6-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-in-post/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv6";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv6-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-out-pre/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv6";

         uses rib-ext-route-annotations;
     }

     augment "/rt:routing/rt:ribs/bgprib:rib/bgprib:afi-safis/" +
       "bgprib:afi-safi/bgprib:ipv6-unicast/" +
       "bgprib:neighbors/bgprib:neighbor/" +
       "bgprib:adj-rib-out-post/bgprib:routes/bgprib:route" {
         description
           "Add extended annotations to Adj-RIB for IPv6";

         uses rib-ext-route-annotations;
     }
   }
   <CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-rib-types@2019-02-25.yang"
   module ietf-bgp-rib-types {
     yang-version "1.1";
     namespace "urn:ietf:params:xml:ns:yang:ietf-bgp-rib-types";
     prefix "brt";

     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),



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                 Susan Hares (shares at ndzh.com";

     description
       "Defines identity and type definitions associated with
        the BGP RIB modules";

     revision "2019-02-25" {
       description
         "Initial Version";
       reference
         "RFC XXX, BGP Model for Service Provider Network.";
     }

     identity invalid-route-reason {
       description
         "Base identity for reason code for routes that are rejected as
          invalid.  Some derived entities are based on BMP v3";
       reference
         "BGP Monitoring Protocol (draft-ietf-grow-bmp-07)";
     }

     identity invalid-cluster-loop {
       base invalid-route-reason;
       description
         "Route was invalid due to CLUSTER_LIST loop";
     }

     identity invalid-as-loop {
       base invalid-route-reason;
       description
         "Route was invalid due to AS_PATH loop";
     }

     identity invalid-originator {
       base invalid-route-reason;
       description
         "Route was invalid due to ORIGINATOR_ID, e.g., update has
         local router as originator";
     }

     identity invalid-confed {
       base invalid-route-reason;
       description
         "Route was invalid due to a loop in the AS_CONFED_SEQUENCE or
          AS_CONFED_SET attributes";
     }

     identity bgp-not-selected-bestpath {



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       description
         "Base identity for indicating reason a route was was not
          selected by BGP route selection algorithm";
       reference
         "RFC 4271 - Section 9.1";
     }

     identity local-pref-lower {
       base bgp-not-selected-bestpath;
       description
         "Route has a lower localpref attribute than current best path";
       reference
         "RFC 4271 - Section 9.1.2";
     }

     identity as-path-longer {
       base bgp-not-selected-bestpath;
       description
         "Route has a longer AS path attribute than current best path";
       reference
         "RFC 4271 - Section 9.1.2.2 (a)";
     }

     identity origin-type-higher {
       base bgp-not-selected-bestpath;
       description
         "Route has a higher origin type, i.e., IGP origin is preferred
         over EGP or incomplete";
       reference
         "RFC 4271 - Section 9.1.2.2 (b)";
     }

     identity med-higher {
       base bgp-not-selected-bestpath;
       description
         "Route has a higher MED, or metric, attribute than the current
          best path";
       reference
         "RFC 4271 - Section 9.1.2.2 (c)";
     }

     identity prefer-external {
       base bgp-not-selected-bestpath;
       description
         "Route source is via IGP, rather than EGP.";
       reference
         "RFC 4271 - Section 9.1.2.2 (d)";
     }



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     identity nexthop-cost-higher {
       base bgp-not-selected-bestpath;
       description
         "Route has a higher interior cost to the next hop.";
       reference
         "RFC 4271 - Section 9.1.2.2 (e)";
     }

     identity higher-router-id {
       base bgp-not-selected-bestpath;
       description
         "Route was sent by a peer with a higher BGP Identifier value,
         or router id";
       reference
         "RFC 4271 - Section 9.1.2.2 (f)";
     }

     identity higher-peer-address {
       base bgp-not-selected-bestpath;
       description
         "Route was sent by a peer with a higher IP address";
       reference
         "RFC 4271 - Section 9.1.2.2 (g)";
     }

     identity bgp-not-selected-policy {
       description
         "Base identity for reason code for routes that are rejected
          due to policy";
     }

     identity rejected-import-policy {
       base bgp-not-selected-policy;
       description
         "Route was rejected after apply import policies";
     }

     identity tunnel-encapsulation-type {
       description
         "Types of tunnel encapsulation, as described by the Tunnel
          Encapsulation attribute";
       reference
         "RFC5512";
     }

     identity srte-policy {
       description
         "Segment Routing Traffic Engineering Policy.";



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       reference
         "TODO: Insert reference here.";
     }

     identity srte-policy-ipv4 {
       base srte-policy;
       description
         "Segment Routing Traffice Engineering Policy for IPv4.";
       reference
         "TODO: Insert reference here.";
     }

     identity srte-policy-ipv6 {
       base srte-policy;
       description
         "Segment Routing Traffic Engineering Policy for IPv6.";
       reference
         "TODO: Insert reference here.";
     }

     identity srte-policy-tunnel {
       base tunnel-encapsulation-type;
       description
         "Segment Routing Traffic Engineering Policy tunnel.";
       reference
         "draft-previdi-idr-segment-routing-te-policy";
     }

     identity tunnel-encapsulation-subtlv-type {
       description
         "SubTLVs of the Tunnel Encapsulation attribute";
       reference
         "RFC5512";
     }

     identity tunnel-remote-endpoint {
       base tunnel-encapsulation-subtlv-type;
       description
         "Remote endpoint of the tunnel.";
       reference
         "RFC5512";
     }

     identity tunnel-color {
       base tunnel-encapsulation-subtlv-type;
       description
         "Colour of the tunnel";
       reference



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         "RFC5512";
     }

     identity srte-preference {
       base tunnel-encapsulation-subtlv-type;
       description
         "Preference of the SR-TE policy entry described by
          the tunnel encapsulation attribute.";
       reference
         "draft-previdi-idr-segment-routing-te-policy";
     }

     identity srte-binding-sid {
       base tunnel-encapsulation-subtlv-type;
       description
         "Binding SID to be used by the SR-TE policy described
          by the tunnel encapsulation attribute.";
       reference
         "draft-previdi-idr-segment-routing-te-policy";
     }

     identity srte-segment-list {
       base tunnel-encapsulation-subtlv-type;
       description
         "Segment lists to be used by the SR-TE policy described
          by the tunnel encapsulation attribute.";
       reference
         "draft-previdi-idr-segment-routing-te-policy";
     }

     identity srte-segment-list-subtlv {
       description
         "SubTLVs of the SR-TE Policy Segment List sub-TLV of the
          Tunnel Encapsulation attribute.";
       reference
         "draft-previdi-idr-segment-routing-te-policy";
     }

     identity srte-segment-list-weight {
       base srte-segment-list-subtlv;
       description
         "Weight of the segment list within the SR-TE policy";
       reference
         "draft-previdi-idr-segment-routing-te-policy";
     }

     identity srte-segment-list-segment {
       base srte-segment-list-subtlv;



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       description
         "An individual element within the SR-TE Policy Segment
          List.";
     }
   }
   <CODE ENDS>


<CODE BEGINS> file "ietf-bgp-rib-attributes@2019-02-25.yang"
submodule ietf-bgp-rib-attributes {
  yang-version "1.1";
  belongs-to ietf-bgp-rib {
    prefix "br";
  }

  // import some basic types
  import ietf-bgp-types {
    prefix bgpt;
  }

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

  import ietf-inet-types {
    prefix inet;
  }

  // meta
  organization
    "IETF IDR Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/idr>
     WG List:  <idr@ietf.org>

     Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
              Keyur Patel (keyur at arrcus.com),
              Susan Hares (shares at ndzh.com";

  description
    "This submodule contains common data definitions for BGP
     attributes for use in BGP RIB tables.";


  revision "2019-02-25" {
    description
      "Initial version";



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    reference
      "RFC XXXX: BGP YANG Model for Service Provider Network";
  }

  grouping bgp-as-path-attr {
    description
      "Data for representing BGP AS-PATH attribute";

    leaf type {
      type identityref {
        base bgpt:as-path-segment-type;
      }
      description
        "The type of AS-PATH segment";
    }

    leaf-list member {
      type inet:as-number;
      description
        "List of the AS numbers in the AS-PATH segment";
    }
  }

  grouping bgp-as-path-attr-top {
    description
      "Top-level grouping for AS-PATH attribute data";

    container as-path {
      description
        "Enclosing container for the list of AS path segments.

        In the Adj-RIB-In or Adj-RIB-Out, this list should show
        the received or sent AS_PATH, respectively.  For
        example, if the local router is not 4-byte capable, this
        value should consist of 2-octet ASNs or the AS_TRANS
        (AS 23456) values received or sent in route updates.

        In the Loc-RIB, this list should reflect the effective
        AS path for the route, e.g., a 4-octet value if the
        local router is 4-octet capable.";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)
        RFC 6793 - BGP Support for Four-octet AS Number Space
        RFC 5065 - Autonomous System Confederations for BGP";

      list segment {
        key "type";




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        config false;
        uses bgp-as-path-attr;
        description
          "List of AS PATH segments";
      }
    }
  }

  grouping bgp-as4-path-attr-top {
    description
      "Top-level grouping for AS4-PATH attribute data";

    container as4-path {
      description
        "This is the path encoded with 4-octet
        AS numbers in the optional transitive AS4_PATH attribute.
        This value is populated with the received or sent attribute
        in Adj-RIB-In or Adj-RIB-Out, respectively.  It should not
        be populated in Loc-RIB since the Loc-RIB is expected to
        store the effective AS-Path in the as-path leaf regardless
        of being 4-octet or 2-octet.";
      reference
          "RFC 6793 - BGP Support for Four-octet AS Number Space";

      list segment {
        key "type";

        config false;
        uses bgp-as-path-attr;
        description
          "List of AS PATH segments";
      }
    }
  }

  grouping bgp-community-attr-state {
    description
      "Common definition of BGP community attributes";

    leaf-list community {
      type union {
        type bgpt:bgp-well-known-community-type;
        type bgpt:bgp-std-community-type;
      }
      description
        "List of standard or well-known BGP community
        attributes.";
    }



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  }

  grouping bgp-extended-community-attr-state {
    description
      "Common definition of BGP extended community attribute";

    leaf-list ext-community {
      // type bgpt:bgp-ext-community-recv-type;
      type bgpt:bgp-ext-community-type;
      description
        "List of BGP extended community attributes.  The received
        extended community may be an explicitly modeled
        type or unknown, represented by an 8-octet value
        formatted according to RFC 4360.";
      reference
        "RFC 4360 - BGP Extended Communities Attribute";
    }

  }

  grouping bgp-aggregator-attr-top {
    description
      "Common definition of the BGP aggregator attribute";

    container aggregator {
      config false;
      description
        "BGP attribute indicating the prefix has been aggregated by
         the specified AS and router.";

      leaf as {
        type inet:as-number;
        description
          "AS number of the autonomous system that performed the
           aggregation.";
      }

      leaf as4 {
        type inet:as-number;
        description
          "AS number of the autonomous system that performed the
           aggregation (4-octet representation).  This value is
           populated if an upstream router is not 4-octet capable.
           Its semantics are similar to the AS4_PATH optional
           transitive attribute";
        reference
          "RFC 6793 - BGP Support for Four-octet AS Number Space";
      }



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      leaf address {
        type inet:ipv4-address;
        description
          "IP address of the router that performed the
           aggregation.";
      }
    }
  }

  grouping bgp-shared-common-attr-state {
    description
      "Route attributes shared across route table entries,
      common to both LOC-Rib and Adj-RIB";


    leaf origin {
      type bgpt:bgp-origin-attr-type;
      description
        "BGP attribute defining the origin of the path information.";
    }

    leaf atomic-aggregate {
      type boolean;
      description
        "BGP attribute indicating that the prefix is an atomic
        aggregate, i.e., the peer selected a less specific
        route without selecting a more specific route that is
        included in it.";
    }

    leaf next-hop {
      type inet:ip-address;
      description
        "BGP next hop attribute defining the IP address of the router
        that should be used as the next hop to the destination";
    }

    leaf med {
      type uint32;
      description
        "BGP multi-exit discriminator attribute used in BGP route
        selection process";
    }

    leaf local-pref {
      type uint32;
      description
        "BGP local preference attribute sent to internal peers to



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        indicate the degree of preference for externally learned
        routes.  The route with the highest local preference value
        is preferred.";
    }

    leaf originator-id {
      type inet:ipv4-address;
      description
        "BGP attribute that provides the id as an IPv4 address
        of the originator of the announcement.";
      reference
        "RFC 4456 - BGP Route Reflection: An Alternative to Full
        Mesh Internal BGP (IBGP)";
    }

    leaf-list cluster-list {
      type inet:ipv4-address;
      description
        "Represents the reflection path that the route has passed.";
      reference
        "RFC 4456 - BGP Route Reflection: An Alternative to Full
        Mesh Internal BGP (IBGP)";
    }

    leaf aigp {
      type uint64;
      description
        "BGP path attribute representing the accumulated IGP metric
        for the path";
      reference
        "RFC 7311 - The Accumulated IGP Metric Attribute for BGP";
    }
  }

  grouping bgp-unknown-attr-flags-state {
    description
      "Operational state data for path attribute flags";

    leaf optional {
      type boolean;
      description
        "Defines whether the attribute is optional (if
         set to true) or well-known (if set to false).
         Set in the high-order bit of the BGP attribute
         flags octet.";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";
    }



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    leaf transitive {
      type boolean;
      description
        "Defines whether an optional attribute is transitive
        (if set to true) or non-transitive (if set to false).  For
        well-known attributes, the transitive flag must be set to
        true.  Set in the second high-order bit of the BGP attribute
        flags octet.";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";
    }

    leaf partial {
      type boolean;
      description
        "Defines whether the information contained in the optional
        transitive attribute is partial (if set to true) or complete
        (if set to false).  For well-known attributes and for
        optional non-transitive attributes, the partial flag
        must be set to false.  Set in the third high-order bit of
        the BGP attribute flags octet.";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";
    }

    leaf extended {
      type boolean;
      description
        "Defines whether the attribute length is one octet
        (if set to false) or two octets (if set to true).  Set in
        the fourth high-order bit of the BGP attribute flags
        octet.";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";
    }
  }

  grouping bgp-unknown-attr-state {
    description
      "Operational state data for path attributes not shared
      across route entries, common to LOC-RIB and Adj-RIB";

    leaf attr-type {
      type uint8;
      description
        "1-octet value encoding the attribute type code";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";



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    }

    leaf attr-len {
      type uint16;
      description
        "One or two octet attribute length field indicating the
        length of the attribute data in octets.  If the Extended
        Length attribute flag is set, the length field is 2 octets,
        otherwise it is 1 octet";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";
    }

    leaf attr-value {
      type binary {
        length 1..65535;
      }
      description
        "Raw attribute value, not including the attribute
        flags, type, or length.  The maximum length
        of the attribute value data is 2^16-1 per the max value
        of the attr-len field (2 octets).";
      reference
        "RFC 4271 - A Border Gateway Protocol 4 (BGP-4)";
    }
  }

  grouping bgp-unknown-attr-top {
    description
      "Unknown path attributes that are not expected to be shared
      across route entries, common to LOC-RIB and Adj-RIB";

    container unknown-attributes {
      description
        "Unknown path attributes that were received in the UPDATE
        message which contained the prefix.";

      list unknown-attribute {
        key "attr-type";
        description
          "This list contains received attributes that are unrecognized
          or unsupported by the local router.  The list may be empty.";

        uses bgp-unknown-attr-flags-state;
        uses bgp-unknown-attr-state;
      }
    }
  }



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  grouping bgp-loc-rib-attr-state {
    description
      "Path attributes that are not expected to be shared across
      route entries, specific to LOC-RIB";

  }

  grouping bgp-adj-rib-attr-state {
    description
      "Path attributes that are not expected to be shared across
      route entries, specific to Adj-RIB";

    leaf path-id {
      type uint32;
      description
        "When the BGP speaker supports advertisement of multiple
        paths for a prefix, the path identifier is used to
        uniquely identify a route based on the combination of the
        prefix and path id.  In the Adj-RIB-In, the path-id value is
        the value received in the update message.   In the Loc-RIB,
        if used, it should represent a locally generated path-id
        value for the corresponding route.  In Adj-RIB-Out, it
        should be the value sent to a neighbor when add-paths is
        used, i.e., the capability has been negotiated.";
      reference
        "draft-ietf-idr-add-paths - Advertisement of Multiple Paths
        in BGP";
    }
  }

  grouping bgp-tunnel-encapsulation-attr-top {
    description
      "Top-level definition of the BGP Tunnel encapsulation
      attribute.";

    container tunnel-encapsulation {
      config false;
      description
        "The Tunnel Encapsulation attribute specifies a set of
        tunnels to a remote destination. The attribute is TLV
        based and allows description of a tunnel type, and the
        relevant information to create the tunnel to the remote
        destination.";

      reference "RFC5512, draft-ietf-idr-tunnel-encaps";

      container tunnels {
        description



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          "Surrounding container for the set of tunnels included
          within the tunnel encapsulation attribute.";

        list tunnel {
          key "type";
          description
            "List of the tunnels that are specified within the
            attribute. Keyed on the type of tunnel that the
            TLV describes.";

          leaf type {
            type identityref {
              base "bgprt:tunnel-encapsulation-type";
            }
            description
              "Type of the tunnel described within the tunnel
               encapsulation attribute.";
          }

          container subtlvs {
            description
              "Surrounding container for the list of sub-TLVs within
              the tunnel encapsulation attribute.";

            list subtlv {
              key "type";
              description
                "List of the subTLVs that are specified within the
                 TLV instance inside the tunnel encapsulation
                 attribute.";

              leaf type {
                type identityref {
                  base "bgprt:tunnel-encapsulation-subtlv-type";
                }
                description
                  "Type of the sub-TLV within the tunnel encapsulation
                   attribute";
              }

              leaf-list colors {
                when "../type = 'bgprt:tunnel-color'" {
                  description
                    "Only allow list of colors to be specified when
                     the sub-TLV specifies colors associated with the
                     tunnel encapsulation attribute.";
                }
                type uint32;



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                description
                  "The colors associated with the tunnel encapsulation
                   attribute, as described by RFC5512.";
              }

              leaf preference {
                when "../type = 'bgprt:srte-preference'" {
                  description
                    "Only allow the preference to be specified when the
                     sub-TLV specifies the preference associated with
                     the tunnel encapsulation attribute.";
                }
                type uint32;
                default 100;
                description
                  "The preference of the SR-TE policy described by the
                   tunnel encapsulation attribute. If unspecified, the
                   preference defaults to 100.";
              }

              leaf binding-sid {
                when "../type = 'bgprt:srte-binding-sid'" {
                  description
                    "Only allow the binding SID to be specified when the
                     sub-TLV is specified to be the of the relevant
                     type.";
                }
                // type sr:sr-sid-type;
                // defining it as string, till we figure what this
                // should be.
                type string;
                description
                  "Binding SID associated with the SR-TE policy";
              }

              container remote-endpoints {
                when "../type = 'bgprt:tunnel-remote-endpoint'" {
                  description
                    "Only allow the remote endpoint to be specified
                     when the subTLV is specified to describe remote
                     endpoints.";
                }

                description
                  "The remote endpoints associated with the tunnel
                   described by the attribute.";

                list remote-endpoint {



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                  key "endpoint";
                  config false;
                  description
                    "List of the remote endpoints described within
                     the TLV.";

                  leaf as {
                    type inet:as-number;
                    description
                      "The remote AS to which the IP address of the
                       remote endpoint belongs.";
                  }

                  leaf endpoint {
                    type inet:ip-address;
                    description
                      "IP address of the remote endpoint.";
                  }
                }
              }

              container segment-lists {
                when "../type = 'bgprt:srte-segment-list'" {
                  description
                    "Only allow the segment lists to be specified when
                     the sub-TLV is of the relevant type.";
                }

                description
                  "Surrounding container for the list of segment lists
                   that are associated with a SR-TE Policy tunnel.";

                list segment-list {
                  key "instance-id";
                  config false;

                  description
                    "List of segment lists that are specified within the
                    tunnel encapsulation attribute.";

                  leaf instance-id {
                    type uint64;
                    description
                      "Instance of the segment list within the
                         sub-TLV";
                  }

                  leaf weight {



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                    type uint32;
                    description
                      "The weight given to the path within the set of
                         segment lists that are included in the tunnel
                         attribute sub-TLV.";
                  }

                  container segments {
                    description
                      "Surrounding container for the list of segments
                       within the SR-TE segment list.";

                    list segment {
                      key "index";

                      config false;
                      description
                        "List of segments within the SR-TE segment
                         list.";

                      leaf index {
                        type uint64;
                        description
                          "Index of the segment within the segment
                             list. The segments are ordered in ascending
                             order, beginning at 0.";
                      }

                      leaf type {
                        type enumeration {
                          enum MPLS_SID {
                            value 1;
                            description
                            "The segment is specified as an MPLS
                             label.";
                          }
                          enum IPV6_SID {
                            value 2;
                            description
                            "The segment is specified as an IPv6
                             address.";
                          }
                          enum IPV4_NODE_ADDRESS {
                            value 3;
                            description
                            "The segment is specified as an IPv4
                             node address with optional SID.";
                          }



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                          enum IPV6_NODE_ADDRESS {
                            value 4;
                            description
                            "The segment is specified as an IPv6
                             node address with optional SID.";
                          }
                          enum IPV4_LOCAL_INTF_ID {
                            value 5;
                            description
                            "The segment is specified as an IPv4
                             address with a local interface
                             identifier along with an .";
                          }
                          enum IPV4_LOCAL_REMOTE_ADDR {
                            value 6;
                            description
                            "The segment is specified as an IPv4
                             local and remote address with an
                             optional SID.";
                          }
                          enum IPV6_LOCAL_INTF_ID {
                            value 7;
                            description
                            "The segment is specified as an IPv6
                             address with an index, along with an
                             optional SID.";
                          }
                          enum IPV6_LOCAL_REMOTE_ADDR {
                            value 8;
                            description
                            "The segmetn is specified as an IPv6
                             local and remote address with an
                             optional SID.";
                          }
                        }
                        description
                          "The type of segment specified within the
                             segment entry.";
                      }

                      leaf sid {
                        // TODO:     type sr:sr-sid-type;
                        // using string till this is resolved.
                        type string;
                        description
                          "SID value for the segment entry, specified
                             as an MPLS label or IPv6 address.";
                      }



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                      leaf mpls-tc {
                        when "../type = 'MPLS_SID'" {
                          description
                            "The MPLS TC bits can only be specified
                               when the segment time is an MPLS label.";
                        }
                        type uint8 {
                          range "0..7";
                        }
                        description
                          "The MPLS TC bits used when the SID is
                             specified as an MPLS label. If set to zero,
                             the receiving system specifies the value of
                             the TC bits.";
                      }

                      leaf mpls-bos {
                        when "../type = 'MPLS_SID'" {
                          description
                            "The MPLS BoS bit can only be specified
                               when the segment type is an MPLS label.";
                        }
                        type boolean;
                        description
                          "When this leaf is set to true the MPLS
                             bottom-of-stack (BoS) bit is set in the
                             MPLS segment. The BoS bit should  always be
                             set to zero by the sender.";
                      }

                      leaf mpls-ttl {
                        when "../type = 'MPLS_SID'" {
                          description
                            "The MPLS TTL can only be set when the
                               segment type is an MPLS label.";
                        }
                        type uint8;
                        description
                          "The MPLS time to live (TTL) to be set for
                             the MPLS segment. If set to 255, the
                             receiver specifies the TTL value that is
                             used for packets sent with this segment in
                             the stack.";
                      }

                      leaf remote-ipv4-address {
                        when "../type = 'IPV4_NODE_ADDRESS' or" +
                          //  "../type='../IPV4_ADDRESS_INDEX' or" +



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                          "../type='IPV4_LOCAL_INTF_ID' or " +
                          "../type='IPV4_LOCAL_REMOTE_ADDR'" {
                          description
                            "An IPv4 address can only be associated
                               with the segment entry when the type of
                               the SID is a node address, or an IPv6
                               address with an index.";
                        }
                        type inet:ipv4-address;
                        description
                          "An IPv4 address specified as the remote
                             node address. When the type of the segment
                             specifies only the remote address, no other
                             addresses are specified. When the type of
                             the segment requires a local address,
                             this leaf specifies the remote IPv4
                             address.";
                      }

                      leaf local-ipv4-address {
                        when "../type = 'IPV4_LOCAL_REMOTE_ADDR'" {
                          description
                            "A local IPv4 address can only be specified
                               when the segment is specified by the
                               local and remote IPv4 interface
                               addresses.";
                        }
                        type inet:ipv4-address;
                        description
                          "An IPv4 address of a local adjacency that is
                             used to identify the segment.";
                      }

                      leaf remote-ipv6-address {
                        when "../type = 'IPV6_NODE_ADDRESS' or" +
                          //  "../type='IPV6_ADDRESS_INDEX' or" +
                          "../type='IPV6_LOCAL_INTF_ID' or " +
                          "../type='IPV6_LOCAL_REMOTE_ADDR'" {
                          description
                            "An IPv6 address can only be specified with
                               a segment entry when the type of the SID
                               is a node address, or an IPv6 address
                               with an index.";
                        }
                        type inet:ipv6-address;
                        description
                          "An IPv6 address specified as the remote node
                             address. When the type of the segment



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                             specifies only the remote address, no other
                             addresses are specified. When the type of
                             the segment requires a local address,
                             this leaf specifies the remote IPv6
                             address.";
                      }

                      leaf local-ipv6-address {
                        when "../type = 'IPV6_LOCAL_REMOTE_ADDR'" {
                          description
                            "A local IPv6 address can only be
                               specified when the segment is specified
                               by the local and remote IPv6 interface
                               addresses.";
                        }
                        type inet:ipv6-address;
                        description
                          "An IPv6 address of a local adjacency that is
                             used to identify the segment.";
                      }

                      leaf local-interface-id {
                        when "../type = 'IPV4_LOCAL_INTF_ID' or" +
                          "../type='IPV6_LOCAL_INTF_ID'" {
                          description
                            "A local interface identifier can only be
                               specified when the type of the segment
                               is an IPv4 address with local interface
                               ID, or IPv6 address with local interface
                               ID.";
                        }
                        type uint32;
                        description
                          "The local interface identifier to be
                             utilised for the segment.";
                        reference
                          "draft-ietf-pce-segment-routing";
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }



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}
<CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-rib-shared-attributes@2019-02-25.yang"
   submodule ietf-bgp-rib-shared-attributes {
     yang-version "1.1";
     belongs-to ietf-bgp-rib {
       prefix "br";
     }

     // import some basic types
     include ietf-bgp-rib-attributes;

     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This submodule contains structural data definitions for
        attribute sets shared across routes.";

     revision "2019-02-25" {
       description
         "Initial version";
       reference
         "RFC XXXX: BGP YANG Model for Service Provider Network.";
     }

     grouping attribute-sets {
       description
         "Top level grouping for list of common attribute sets";

       container attr-sets {
         description
           "Enclosing container for the list of path attribute sets";

         list attr-set {
           key "index";

           description



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             "List of path attributes that may be in use by multiple
             routes in the table";

           leaf index {
             type uint64;
             description
               "System generated index for each attribute set.  The
                 index is used to reference an attribute set from a
                 specific path.  Multiple paths may reference the same
                 attribute set.";
           }

           uses bgp-shared-common-attr-state;
           uses bgp-aggregator-attr-top;
           uses bgp-as-path-attr-top;
           uses bgp-as4-path-attr-top;
           uses bgp-tunnel-encapsulation-attr-top;
         }
       }
     }

     grouping community-sets {
       description
         "Top level grouping for list of shared community attribute
         sets";

       container communities {
         description
           "Enclosing container for the list of community attribute
           sets";

         list community {
           key "index";

           config false;
           description
             "List of path attributes that may be in use by multiple
             routes in the table";

           leaf index {
             type uint64;
             description
               "System generated index for each attribute set.  The
                 index is used to reference an attribute set from a
                 specific path.  Multiple paths may reference the same
                 attribute set.";
           }




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           uses bgp-community-attr-state;
         }
       }
     }

     grouping ext-community-sets {
       description
         "Top level grouping for list of extended community attribute
         sets";

       container ext-communities {
         description
           "Enclosing container for the list of extended community
           attribute sets";

         list ext-community {
           key "index";

           config false;
           description
             "List of path attributes that may be in use by multiple
             routes in the table";

           leaf index {
             type uint64;
             description
               "System generated index for each attribute set.  The
                 index is used to reference an attribute set from a
                 specific path.  Multiple paths may reference the same
                 attribute set.";
           }

           uses bgp-extended-community-attr-state;
         }
       }
     }
   }
   <CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-rib-table-attributes@2019-02-25.yang"
   submodule ietf-bgp-rib-table-attributes {
     yang-version "1.1";
     belongs-to ietf-bgp-rib {
       prefix "br";
     }

     // import some basic types



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     import ietf-yang-types { prefix types; }
     import ietf-bgp-rib-types { prefix bgpribt; }

     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This submodule contains common data definitions for data
        related to a RIB entry, or RIB table.";


     revision "2019-02-25" {
       description
         "Initial version.";
       reference
         "RFC XXXX: BGP YANG Model for Service Provider Network.";
     }

     grouping bgp-common-route-annotations-state {
       description
         "Data definitions for flags and other information attached
         to routes in both LOC-RIB and Adj-RIB";

       leaf last-modified {
         type types:timeticks;
         description
           "Timestamp when this path was last modified.

           The value is the timestamp in seconds relative to
           the Unix Epoch (Jan 1, 1970 00:00:00 UTC).";
       }

       leaf valid-route {
         type boolean;
         description
           "Indicates that the route is considered valid by the
           local router";
       }

       leaf invalid-reason {



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         type identityref {
           base bgpribt:invalid-route-reason;
         }
         description
           "If the route is rejected as invalid, this indicates the
           reason.";
       }

     }

     grouping bgp-loc-rib-route-annotations-state {
       description
         "Data definitions for information attached to routes in the
         LOC-RIB";

       // placeholder for route metadata specific to the LOC-RIB

     }

     grouping bgp-adj-rib-in-post-route-annotations-state {
       description
         "Data definitions for information attached to routes in the
         Adj-RIB-in post-policy table";

       leaf best-path {
         type boolean;
         description
           "Current path was selected as the best path.";
       }
     }

     grouping bgp-common-table-attrs-state {
       description
         "Common attributes attached to all routing tables";

       // placeholder for metadata associated with all tables
     }

     grouping bgp-common-table-attrs-top {
       // no enclosing container as this data will fit under an
       // existing LOC-RIB container

       uses bgp-common-table-attrs-state;
       description
         "Operational state data for data related to the entire
          LOC-RIB";
     }
   }



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   <CODE ENDS>


<CODE BEGINS> file "ietf-bgp-rib-tables@2019-02-25.yang"
submodule ietf-bgp-rib-tables {
  yang-version "1.1";
  belongs-to ietf-bgp-rib {
    prefix "br";
  }

  // import some basic types
  import ietf-inet-types {
    prefix inet;
  }

  import ietf-routing {
    prefix "rt";
    reference
      "RFC 8022: A YANG Data Model for Routing Management";
  }

  include ietf-bgp-rib-attributes;
  include ietf-bgp-rib-shared-attributes;
  include ietf-bgp-rib-table-attributes;

  organization
    "IETF IDR Working Group";

  contact
    "WG Web:   <http://tools.ietf.org/wg/idr>
     WG List:  <idr@ietf.org>

     Editor:  Mahesh Jethanandani (mjethanandani@gmail.com)
     Authors: Keyur Patel,
              Mahesh Jethanandani,
              Susan Hares";

  description
    "This submodule contains structural data definitions for
     BGP routing tables.";

  revision "2019-02-25" {
    description
      "Initial Version";
    reference
      "RFC XXXX, BGP YANG Model for Service Provider Network.";
  }




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  grouping bgp-adj-rib-common-attr-refs {
    description
      "Definitions of common references to attribute sets for
      multiple AFI-SAFIs for Adj-RIB tables";

    leaf attr-index {
      type leafref {
        path "../../../../../../../../../attr-sets/attr-set/" +
          "index";
      }
      description
        "Reference to the common attribute group for the
        route";
    }

    leaf community-index {
      type leafref {
        path "../../../../../../../../../communities/community/" +
          "index";
      }
      description
        "Reference to the community attribute for the route";
    }

    leaf ext-community-index {
      type leafref {
        path "../../../../../../../../../ext-communities/" +
          "ext-community/index";
      }
      description
        "Reference to the extended community attribute for the
        route";
    }
  }

  grouping bgp-loc-rib-common-attr-refs {
    description
      "Definitions of common references to attribute sets for
      multiple AFI-SAFIs for LOC-RIB tables";

    leaf attr-index {
      type leafref {
        path "../../../../../../../attr-sets/attr-set/" +
          "index";
      }
      description
        "Reference to the common attribute group for the
        route";



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    }

    leaf community-index {
      type leafref {
        path "../../../../../../../communities/community/" +
          "index";
      }
      description
        "Reference to the community attribute for the route";
    }

    leaf ext-community-index {
      type leafref {
        path "../../../../../../../ext-communities/" +
          "ext-community/index";
      }
      description
        "Reference to the extended community attribute for the
        route";
    }
  }

  grouping bgp-loc-rib-common-keys {
    description
      "Common references used in keys for IPv4 and IPv6
      LOC-RIB entries";

    leaf origin {
      type union {
        type inet:ip-address;
        type identityref {
          base rt:routing-protocol;
        }
      }
      description
        "Indicates the origin of the route.  If the route is learned
        from a neighbor, this value is the neighbor address.  If
        the route was injected or redistributed from another
        protocol, the origin indicates the source protocol for the
        route.";
    }

    leaf path-id {
      type uint32;
      // TODO: YANG does not allow default values for key
      // default 0;
      description
        "If the route is learned from a neighbor, the path-id



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        corresponds to the path-id for the route in the
        corresponding adj-rib-in-post table.  If the route is
        injected from another protocol, or the neighbor does not
        support BGP add-paths, the path-id should be set
        to zero, also the default value.";
    }
  }

  grouping ipv4-loc-rib {
    description
      "Top-level grouping for IPv4 routing tables";

    container loc-rib {
      config false;
      description
        "Container for the IPv4 BGP LOC-RIB data";

      uses bgp-common-table-attrs-top;

      container routes {
        description
          "Enclosing container for list of routes in the routing
          table.";

        list route {
          key "prefix origin path-id";

          description
            "List of routes in the table, keyed by the route
            prefix, the route origin, and path-id.  The route
            origin can be either the neighbor address from which
            the route was learned, or the source protocol that
            injected the route.  The path-id distinguishes routes
            for the same prefix received from a neighbor (e.g.,
            if add-paths is eanbled).";

          leaf prefix {
            type inet:ipv4-prefix;
            description
              "The IPv4 prefix corresponding to the route";
          }

          uses bgp-loc-rib-common-keys;
          uses bgp-loc-rib-common-attr-refs;
          uses bgp-loc-rib-attr-state;
          uses bgp-common-route-annotations-state;
          uses bgp-loc-rib-route-annotations-state;
          uses bgp-unknown-attr-top;



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        }
      }
    }
  }

  grouping ipv6-loc-rib {
    description
      "Top-level grouping for IPv6 routing tables";

    container loc-rib {
      config false;
      description
        "Container for the IPv6 BGP LOC-RIB data";

      uses bgp-common-table-attrs-top;

      container routes {
        description
          "Enclosing container for list of routes in the routing
          table.";

        list route {
          key "prefix origin path-id";

          description
            "List of routes in the table, keyed by the route
            prefix, the route origin, and path-id.  The route
            origin can be either the neighbor address from which
            the route was learned, or the source protocol that
            injected the route.  The path-id distinguishes routes
            for the same prefix received from a neighbor (e.g.,
            if add-paths is eanbled).";

          leaf prefix {
            type inet:ipv6-prefix;
            description
              "The IPv6 prefix corresponding to the route";
          }

          uses bgp-loc-rib-common-keys;
          uses bgp-loc-rib-common-attr-refs;
          uses bgp-loc-rib-attr-state;
          uses bgp-common-route-annotations-state;
          uses bgp-loc-rib-route-annotations-state;
          uses bgp-unknown-attr-top;
        }
      }
    }



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  }

  grouping ipv4-adj-rib-common {
    description
      "Common structural grouping for each IPv4 adj-RIB table";

    uses bgp-common-table-attrs-top;

    container routes {
      config false;
      description
        "Enclosing container for list of routes in the routing
        table.";

      list route {
        key "prefix path-id";

        description
          "List of routes in the table, keyed by a combination of
          the route prefix and path-id to distinguish multiple
          routes received from a neighbor for the same prefix,
          e.g., when BGP add-paths is enabled.";

        leaf prefix {
          type inet:ipv4-prefix;
          description
            "Prefix for the route";
        }

        uses bgp-adj-rib-attr-state;
        uses bgp-adj-rib-common-attr-refs;
        uses bgp-common-route-annotations-state;
        uses bgp-unknown-attr-top;

      }
    }
  }

  grouping ipv4-adj-rib-in-post {
    description
      "Common structural grouping for the IPv4 adj-rib-in
      post-policy table";

    uses bgp-common-table-attrs-top;

    container routes {
      config false;
      description



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        "Enclosing container for list of routes in the routing
        table.";

      list route {
        key "prefix path-id";

        description
          "List of routes in the table, keyed by a combination of
          the route prefix and path-id to distinguish multiple
          routes received from a neighbor for the same prefix,
          e.g., when BGP add-paths is enabled.";

        leaf prefix {
          type inet:ipv4-prefix;
          description
            "Prefix for the route";
        }

        uses bgp-adj-rib-attr-state;
        uses bgp-adj-rib-common-attr-refs;
        uses bgp-common-route-annotations-state;
        uses bgp-adj-rib-in-post-route-annotations-state;
        uses bgp-unknown-attr-top;
      }
    }
  }


  grouping ipv4-adj-rib {
    description
      "Top-level grouping for Adj-RIB table";

    container neighbors {
      config false;
      description
        "Enclosing container for neighbor list";

      list neighbor {
        key "neighbor-address";
        description
          "List of neighbors (peers) of the local BGP speaker";

        leaf neighbor-address {
          type inet:ip-address;
          description
            "IP address of the BGP neighbor or peer";
        }




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        container adj-rib-in-pre {
          description
            "Per-neighbor table containing the NLRI updates
            received from the neighbor before any local input
            policy rules or filters have been applied.  This can
            be considered the 'raw' updates from the neighbor.";

          uses ipv4-adj-rib-common;

        }

        container adj-rib-in-post {
          description
            "Per-neighbor table containing the paths received from
            the neighbor that are eligible for best-path selection
            after local input policy rules have been applied.";

          uses ipv4-adj-rib-in-post;
        }

        container adj-rib-out-pre {
          description
            "Per-neighbor table containing paths eligble for
            sending (advertising) to the neighbor before output
            policy rules have been applied";

          uses ipv4-adj-rib-common;

        }

        container adj-rib-out-post {
          description
            "Per-neighbor table containing paths eligble for
            sending (advertising) to the neighbor after output
            policy rules have been applied";

          uses ipv4-adj-rib-common;

        }
      }
    }
  }

  grouping ipv6-adj-rib-common {
    description
      "Common structural grouping for each IPv6 adj-RIB table";

    uses bgp-common-table-attrs-state;



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    container routes {
      config false;
      description
        "Enclosing container for list of routes in the routing
        table.";

      list route {
        key "prefix path-id";

        description
          "List of routes in the table";

        leaf prefix {
          type inet:ipv6-prefix;
          description
            "Prefix for the route";
        }

        uses bgp-adj-rib-attr-state;
        uses bgp-adj-rib-common-attr-refs;
        uses bgp-common-route-annotations-state;
        uses bgp-unknown-attr-top;
      }
    }
  }

  grouping ipv6-adj-rib-in-post {
    description
      "Common structural grouping for the IPv6 adj-rib-in
      post-policy table";

    uses bgp-common-table-attrs-state;

    container routes {
      config false;
      description
        "Enclosing container for list of routes in the routing
        table.";

      list route {
        key "prefix path-id";

        description
          "List of routes in the table";

        leaf prefix {
          type inet:ipv6-prefix;
          description



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            "Prefix for the route";
        }

        uses bgp-adj-rib-attr-state;
        uses bgp-adj-rib-common-attr-refs;
        uses bgp-common-route-annotations-state;
        uses bgp-adj-rib-in-post-route-annotations-state;
        uses bgp-unknown-attr-top;
      }
    }
  }

  grouping ipv6-adj-rib {
    description
      "Top-level grouping for Adj-RIB table";

    container neighbors {
      config false;
      description
        "Enclosing container for neighbor list";

      list neighbor {
        key "neighbor-address";
        description
          "List of neighbors (peers) of the local BGP speaker";

        leaf neighbor-address {
          type inet:ip-address;
          description
            "IP address of the BGP neighbor or peer";
        }

        container adj-rib-in-pre {
          description
            "Per-neighbor table containing the NLRI updates
            received from the neighbor before any local input
            policy rules or filters have been applied.  This can
            be considered the 'raw' updates from the neighbor.";

          uses ipv6-adj-rib-common;

        }

        container adj-rib-in-post {
          description
            "Per-neighbor table containing the paths received from
            the neighbor that are eligible for best-path selection
            after local input policy rules have been applied.";



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          uses ipv6-adj-rib-in-post;
        }

        container adj-rib-out-pre {
          description
            "Per-neighbor table containing paths eligble for
            sending (advertising) to the neighbor before output
            policy rules have been applied";

          uses ipv6-adj-rib-common;

        }

        container adj-rib-out-post {
          description
            "Per-neighbor table containing paths eligble for
            sending (advertising) to the neighbor after output
            policy rules have been applied";

          uses ipv6-adj-rib-common;

        }
      }
    }
  }

  grouping ipvX-srte-policy-adjrib {
    description
      "Top-level grouping for the IPv4 and IPv6 AFI, SR-TE Policy SAFI
      Adj-RIBs.";

    container neighbors {
      description
        "Surrounding container for the list of neighbours that are
        enabled for the IPv4 and IPv6 AFI, SR-TE Policy SAFI address
        family.";

      list neighbor {
        key "neighbor-address";

        description
          "An individual neighbour that is enabled for the SR-TE
          Policy SAFI.";

        uses ipvX-srte-policy-adjrib-neighbor-state;

        container adj-rib-in-pre {
          description



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            "The Adj-RIB-In for the SR-TE Policy SAFI for the neighbour,
            prior to any inbound policy constraints or modifications
            having been applied.";
          uses ipvX-srte-policy-adjrib-common;
        }

        container adj-rib-in-post {
          description
            "The Adj-RIB-In for the SR-TE Policy SAFI for the neighbour,
            following any inbound policy constraints or modifications
            being made.";
          uses ipvX-srte-policy-adjrib-in-post;
        }

        container adj-rib-out-pre {
          description
            "The Adj-RIB-Out for the SR-TE Policy SAFI for the
             neighbour, prior to any outgoing policy modifications or
             constraints having been applied.";
          uses ipvX-srte-policy-adjrib-common;
        }

        container adj-rib-out-post {
          description
            "The Adj-RIB-Out for the SR-TE Policy SAFI for the
             neighbour, follow any outbound policy constraints or
             modifications being made.";
          uses ipvX-srte-policy-adjrib-common;
        }
      }
    }
  }

  grouping ipvX-srte-policy-adjrib-neighbor-state {
    description
      "Common attributes for each neighbour for which the SR-TE
      Policy SAFI RIBs are being maintained.";

    leaf neighbor-address {
      type inet:ip-address;
      description
        "The address of the neighbour for which the SR-TE policy
         SAFI has been negotiated.";
    }
  }

  grouping ipvX-srte-policy-adjrib-common {
    description



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      "Common structure containing the routes that are learnt via
      the IPv4 or IPv6 SR-TE Policy SAFI.";

    container routes {
      description
        "Surrounding container for the list of routes within the
        SR-TE Policy SAFI.";

      list route {
        key "path-id endpoint color";

        description
          "The routes within the SR-TE Policy SAFI Adj-RIB. The
          routes are keyed on the path-id - set to a non-zero
          value only if ADD-PATHS is being used; the color; and
          the endpoint. The colour and endpoint are extracted from
          the NLRI.";

        uses ipvX-srte-policy-common-route-state;
        uses bgp-adj-rib-common-attr-refs;
        uses bgp-common-route-annotations-state;
        uses bgp-unknown-attr-top;
      }
    }
  }

  grouping ipvX-srte-policy-common-route-state {
    description
      "Common attributes used SR-TE Policy SAFI routes.";

    leaf path-id {
      type uint32;
      // TODO: YANG does not allow default values for key
      // default 0;
      description
        "Identifier for the path when using BGP ADD-PATHS for the SR-TE
        policy SAFI.";
    }

    leaf endpoint {
      type inet:ip-address;
      description
        "A unique identifier for the remote set of nodes. When the
         address family is IPv4, the value is a 4-octet IPv4 address.
         When the address family is IPv6, the value is a 16-octet IPv6
         address.";
    }




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    leaf color {
      type uint32;
      description
        "A 4-octet value identifying the policy. Combined with the
         endpoint the endpoint and colour represent the unique policy.";
    }
  }

  grouping ipvX-srte-policy-adjrib-in-post {
    description
      "Grouping for the post-policy Adj-RIB-In for SR-TE Policy SAFI
       routes";

    container routes {
      description
        "The set of routes that are within the Adj-RIB-Out for the
        neighbour.";

      list route {
        key "path-id endpoint color";

        description
          "The routes that are in the Adj-RIB-In-Post for the specified
          BGP neighbour within the SR-TE Policy SAFI for the specified
          address family.";

        uses ipvX-srte-policy-common-route-state;
        uses bgp-adj-rib-common-attr-refs;
        uses bgp-common-route-annotations-state;
        uses bgp-adj-rib-in-post-route-annotations-state;
        uses bgp-unknown-attr-top;
      }
    }
  }

  grouping ipvX-srte-policy-locrib {
    description
      "Top-level grouping for the Loc-RIB for IPv4 or IPv6 Adj-RIB
      for SR-TE Policy SAFI.";

    container loc-rib {
      description
        "The Loc-RIB for the SR-TE Policy SAFI for IPv4 or IPv6 Unicast
        AFIs.";

      container routes {
        description
          "List of routes within the SR-TE Policy SAFI, for the IPv4 or



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          IPv6 AFI.";

        list route {
          key "path-id endpoint color";

          description
            "Route within the specified address family for the SR-TE
            Policy SAFI.";

          uses ipvX-srte-policy-common-route-state;
          uses bgp-loc-rib-common-attr-refs;
          uses bgp-common-route-annotations-state;
          uses bgp-unknown-attr-top;
        }
      }
    }
  }
}
<CODE ENDS>


   <CODE BEGINS> file "ietf-bgp-rib-table-attributes@2019-02-25.yang"
   submodule ietf-bgp-rib-table-attributes {
     yang-version "1.1";
     belongs-to ietf-bgp-rib {
       prefix "br";
     }

     // import some basic types
     import ietf-yang-types { prefix types; }
     import ietf-bgp-rib-types { prefix bgpribt; }

     organization
       "IETF IDR Working Group";

     contact
       "WG Web:   <http://tools.ietf.org/wg/idr>
        WG List:  <idr@ietf.org>

        Authors: Mahesh Jethanandani (mjethanandani at gmail.com),
                 Keyur Patel (keyur at arrcus.com),
                 Susan Hares (shares at ndzh.com";

     description
       "This submodule contains common data definitions for data
        related to a RIB entry, or RIB table.";





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     revision "2019-02-25" {
       description
         "Initial version.";
       reference
         "RFC XXXX: BGP YANG Model for Service Provider Network.";
     }

     grouping bgp-common-route-annotations-state {
       description
         "Data definitions for flags and other information attached
         to routes in both LOC-RIB and Adj-RIB";

       leaf last-modified {
         type types:timeticks;
         description
           "Timestamp when this path was last modified.

           The value is the timestamp in seconds relative to
           the Unix Epoch (Jan 1, 1970 00:00:00 UTC).";
       }

       leaf valid-route {
         type boolean;
         description
           "Indicates that the route is considered valid by the
           local router";
       }

       leaf invalid-reason {
         type identityref {
           base bgpribt:invalid-route-reason;
         }
         description
           "If the route is rejected as invalid, this indicates the
           reason.";
       }

     }

     grouping bgp-loc-rib-route-annotations-state {
       description
         "Data definitions for information attached to routes in the
         LOC-RIB";

       // placeholder for route metadata specific to the LOC-RIB

     }




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     grouping bgp-adj-rib-in-post-route-annotations-state {
       description
         "Data definitions for information attached to routes in the
         Adj-RIB-in post-policy table";

       leaf best-path {
         type boolean;
         description
           "Current path was selected as the best path.";
       }
     }

     grouping bgp-common-table-attrs-state {
       description
         "Common attributes attached to all routing tables";

       // placeholder for metadata associated with all tables
     }

     grouping bgp-common-table-attrs-top {
       // no enclosing container as this data will fit under an
       // existing LOC-RIB container

       uses bgp-common-table-attrs-state;
       description
         "Operational state data for data related to the entire
          LOC-RIB";
     }
   }
   <CODE ENDS>


8.  Examples

   This section tries to show some examples in how the model can be
   used.

8.1.  Creating BGP Instance

   This example shows how to enable BGP with the IPv4 unicast address
   family, while adding one network to advertise.










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[note: '\' line wrapping for formatting only]

<?xml version="1.0" encoding="UTF-8"?>
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <routing
      xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
    <control-plane-protocols>
      <control-plane-protocol>
        <type
            xmlns:bgp="urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp
        </type>
        <name>name:BGP</name>
        <bgp
            xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
          <global>
            <as>64496</as>
            <afi-safis>
              <afi-safi>
                <afi-safi-name
                    xmlns:bt="urn:ietf:params:xml:ns:yang:ietf-bgp-types">bt:ipv4-\
unicast
                </afi-safi-name>
              </afi-safi>
            </afi-safis>
          </global>
        </bgp>
      </control-plane-protocol>
    </control-plane-protocols>
  </routing>
</config>


8.2.  Neighbor Address Family Configuration

   This example shows how to configure a neighbor.
















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[note: '\' line wrapping for formatting only]

<?xml version="1.0" encoding="UTF-8"?>
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <routing
      xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
    <control-plane-protocols>
      <control-plane-protocol>
        <type
            xmlns:bgp="urn:ietf:params:xml:ns:yang:ietf-bgp">bgp:bgp
        </type>
        <name>name:BGP</name>
        <bgp
            xmlns="urn:ietf:params:xml:ns:yang:ietf-bgp">
          <global>
            <as>64496</as>
            <afi-safis>
              <afi-safi>
                <afi-safi-name
                    xmlns:bt="urn:ietf:params:xml:ns:yang:ietf-bgp-types">bt:ipv4-\
unicast
                </afi-safi-name>
              </afi-safi>
            </afi-safis>
          </global>
          <neighbors>
            <neighbor>
              <neighbor-address>192.0.2.1</neighbor-address>
              <peer-as>64497</peer-as>
              <description>"Peer Router B"</description>
              <afi-safis>
                <afi-safi>
                  <afi-safi-name
                      xmlns:bt="urn:ietf:params:xml:ns:yang:ietf-bgp-types">bt:ipv\
4-unicast
                  </afi-safi-name>
                </afi-safi>
              </afi-safis>
            </neighbor>
          </neighbors>
        </bgp>
      </control-plane-protocol>
    </control-plane-protocols>
  </routing>
</config>






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9.  Contributors

   Previous versions of this document saw contributions from Anees
   Shaikh, Rob Shakir, Kevin D'Souza, Alexander Clemm, Aleksandr
   Zhadkin, and Xyfeng Liu.

10.  Acknowledgements

   The authors are grateful for valuable contributions to this document
   and the associated models from: Ebben Aires, Pavan Beeram, Chris
   Chase, Ed Crabbe, Luyuan Fang, Bill Fenner, Akshay Gattani, Josh
   George, Vijay Gill, Matt John, Jeff Haas, Dhanendra Jain, Acee
   Lindem, Ina Minei, Carl Moberg, Ashok Narayanan, Einar Nilsen-
   Nygaard, Adam Simpson, Puneet Sood, Jason Sterne, Jeff Tantsura, Jim
   Uttaro, and Gunter Vandevelde.

   Credit is also due to authors of the OpenConfig, whose model was
   relied upon to come up with this model.

   Special thanks to Robert Wilton who helped convert the YANG models to
   a NMDA compatible model.

11.  References

11.1.  Normative references

   [RFC1997]  Chandra, R., Traina, P., and T. Li, "BGP Communities
              Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
              <https://www.rfc-editor.org/info/rfc1997>.

   [RFC2439]  Villamizar, C., Chandra, R., and R. Govindan, "BGP Route
              Flap Damping", RFC 2439, DOI 10.17487/RFC2439, November
              1998, <https://www.rfc-editor.org/info/rfc2439>.

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

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4456]  Bates, T., Chen, E., and R. Chandra, "BGP Route
              Reflection: An Alternative to Full Mesh Internal BGP
              (IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006,
              <https://www.rfc-editor.org/info/rfc4456>.




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   [RFC4724]  Sangli, S., Chen, E., Fernando, R., Scudder, J., and Y.
              Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724,
              DOI 10.17487/RFC4724, January 2007,
              <https://www.rfc-editor.org/info/rfc4724>.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              DOI 10.17487/RFC4760, January 2007,
              <https://www.rfc-editor.org/info/rfc4760>.

   [RFC5065]  Traina, P., McPherson, D., and J. Scudder, "Autonomous
              System Confederations for BGP", RFC 5065,
              DOI 10.17487/RFC5065, August 2007,
              <https://www.rfc-editor.org/info/rfc5065>.

   [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>.

   [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>.

   [RFC6811]  Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation", RFC 6811,
              DOI 10.17487/RFC6811, January 2013,
              <https://www.rfc-editor.org/info/rfc6811>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [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>.

   [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>.






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   [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>.

   [RFC8349]  Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
              Routing Management (NMDA Version)", RFC 8349,
              DOI 10.17487/RFC8349, March 2018,
              <https://www.rfc-editor.org/info/rfc8349>.

   [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.ietf-rtgwg-policy-model]
              Qu, Y., Tantsura, J., Lindem, A., and X. Liu, "A YANG Data
              Model for Routing Policy Management", draft-ietf-rtgwg-
              policy-model-05 (work in progress), January 2019.

   [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>.

Authors' Addresses

   Keyur Patel
   Arrcus
   CA
   USA

   Email: keyur@arrcus.com


   Mahesh Jethanandani
   VMware

   Email: mjethanandani@gmail.com











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   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI  48176
   USA

   Email: shares@ndzh.com












































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