Network Working Group                                            L. Wang
Internet-Draft                                                Individual
Intended status: Standards Track                      H. Ananthakrishnan
Expires: May 4, 25, 2016                                      Packet Design
                                                                 M. Chen
                                                                  Huawei
                                                                 A. Dass
                                                                 S. Kini
                                                                Ericsson
                                                              N. Bahadur
                                                       Bracket Computing
                                                       November 1, 22, 2015

          A YANG Data Model for Routing Information Base (RIB)
                   draft-ietf-i2rs-rib-data-model-03
                   draft-ietf-i2rs-rib-data-model-04

Abstract

   This document defines a YANG data model for Routing Information Base
   (RIB) that aligns with the I2RS RIB information model.

Requirements Language

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

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 http://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 May 4, 25, 2016.

Copyright Notice

   Copyright (c) 2015 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
   (http://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
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Definitions and Acronyms  . . . . . . . . . . . . . . . .   3
     1.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Model Structure . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  RIB Capability  . . . . . . . . . . . . . . . . . . . . .   7
     2.2.  Routing Instance and Rib  . . . . . . . . . . . . . . . .   7   8
     2.3.  Route . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     2.4.  Nexthop . . . . . . . . . . . . . . . . . . . . . . . . .   9
     2.5.  RPC Operations  . . . . . . . . . . . . . . . . . . . . .  13  14
     2.6.  Notifications . . . . . . . . . . . . . . . . . . . . . .  16  18
   3.  YANG Modules  . . . . . . . . . . . . . . . . . . . . . . . .  17  19
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  59  63
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  59  63
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  59  63
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  60  64
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  60  64
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  60  64
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  60  64

1.  Introduction

   The Interface to the Routing System (I2RS)
   [I-D.ietf-i2rs-architecture] provides read and write access to the
   information and state within the routing process that exists inside
   the routing elements, this is achieved via the protocol message
   exchange between I2RS clients and I2RS agents associated with the
   routing system.  One of the functions of I2RS is to read and write
   data of Routing Information Base (RIB).
   [I-D.ietf-i2rs-usecase-reqs-summary] introduces a set of RIB use
   cases and the
   cases.  The RIB information model is defined in
   [I-D.ietf-i2rs-rib-info-model].

   This document defines a YANG [RFC6020][RFC6991] data model for the
   RIB that satisfies the RIB use cases and aligns with the RIB
   information model.

1.1.  Definitions and Acronyms

   RIB: Routing Information Base

   Information Model (IM): An abstract model of a conceptual domain,
   independent of a specific implementation or data representation.

1.2.  Tree Diagrams

   A simplified graphical representation of the data model is used in
   this document.  The meaning of the symbols in these diagrams is as
   follows:

   o  Brackets "[" and "]" enclose list keys.

   o  Abbreviations before data node names: "rw" means configuration
      (read-write) and "ro" state data (read-only).

   o  Symbols after data node names: "?" means an optional node and "*"
      denotes a "list" and "leaf-list".

   o  Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

   o  Ellipsis ("...") stands for contents of subtrees that are not
      shown.

2.  Model Structure

   The following figure shows an overview of structure tree of the i2rs-
   rib ietf-
   i2rs-rib module.  To give a whole view of the structure tree, some
   details of the tree are omitted.  The detail relevant details are introduced
   in the following sub-sections.

   module: ietf-i2rs-rib
      +--rw routing-instance
         +--rw name              string
         +--rw interface-list* [name]
         |  +--rw name if:interface-ref
         +--rw router-id?        yang:dotted-quad
         +--rw lookup-limit? uint8
         +--rw rib-list* [name]
            +--rw name            string
            +--rw rib-family      rib-family-def
            +--rw ip-rpf-check?   boolean
            +--rw route-list* [route-index]
               +--rw route-index                uint64
               +--rw match
               |  +--rw (route-type)?
               |     +--:(ipv4)
               |     |  ...
               |     +--:(ipv6)
               |     |  ...
               |     +--:(mpls-route)
               |     |  ...
               |     +--:(mac-route)
               |     |  ...
               |     +--:(interface-route)
               |        ...
               +--rw nexthop
               |  +--rw nexthop-id nexthop-id?            uint32
               |  +--rw sharing-flag sharing-flag?          boolean
               |  +--rw (nexthop-type)?
               |     +--:(nexthop-base)
               |     |  ...
               |     +--:(nexthop-chain) {nexthop-chain}?
               |     |  ...
               |     +--:(nexthop-replicates) {nexthop-replicates}?
               |     |  ...
               |     +--:(nexthop-protection) {nexthop-protection}?
               |     |  ...
               |     +--:(nexthop-load-balance) {nexthop-load-balance}?
               |        ...
               +--rw route-statistic
               |  ...
               +--rw route-attributes
               |  ...
               +--rw route-vendor-attributes
   rpcs:
      +---x rib-add
      |  +--ro  +---w input
      |  |  +--ro  +---w rib-name        string
      |  |  +--ro  +---w rib-family      rib-family-def
      |  |  +--ro  +---w ip-rpf-check?   boolean
      |  +--ro output
      |     +--ro result boolean uint32
      |     +--ro reason? string
      +---x rib-delete
      |  +--ro  +---w input
      |  |  +--ro  +---w rib-name string
      |  +--ro output
      |     +--ro result boolean uint32
      |     +--ro reason? string
      +---x route-add
      |  +--ro  +---w input
      |  |  +--ro  +---w return-failure-detail?   boolean
      |  |  +---w rib-name                 string
      |  |  +--ro  +---w routes
      |  |     +--ro     +---w route-list* [route-index]
      |  |        ...
      |  +--ro output
      |     +--ro result boolean success-count     uint32
      |     +--ro failed-count      uint32
      |     +--ro failure-detail
      |        +--ro failed-routes* [route-index]
      |           +--ro route-index uint32
      |           +--ro error-code? uint32
      +---x route-delete
      |  +--ro  +---w input
      |  |  +--ro  +---w return-failure-detail?   boolean
      |  |  +---w rib-name                 string
      |  |  +--ro  +---w routes
      |  |     +--ro     +---w route-list* [route-index]
      |  |        ...
      |  +--ro output
      |     +--ro result boolean success-count     uint32
      |     +--ro failed-count      uint32
      |     +--ro failure-detail
      |        +--ro failed-routes* [route-index]
      |           +--ro route-index uint32
      |           +--ro error-code? uint32
      +---x route-update
      |  +--ro  +---w input
      |  |  +--ro  +---w return-failure-detail?           boolean
      |  |  +---w rib-name                         string
      |  |  +--ro (match-conditions)?  +---w (match-options)?
      |  |     +--:(match-route-prefix)
      |  |     |  ...
      |  |     +--:(match-route-attributes)
      |  |     |  ...
      |  |     +--:(match-route-vendor-attributes) {...vendor-attributes}? {...}?
      |  |     |  ...
      |  |     +--:(match-nexthop)
      |  |        ...
      |  +--ro output
      |     +--ro result boolean success-count uint32
      |     +--ro failed-count uint32
      |     +--ro failure-detail
      |        +--ro failed-routes* [route-index]
      |           +--ro route-index uint32
      |           +--ro error-code? uint32
      +---x nh-add
      |  +--ro  +---w input
      |  |  +--ro  +---w rib-name              string
      |  |  +--ro nexthop-id  +---w nexthop-id?           uint32
      |  |  +--ro sharing-flag  +---w sharing-flag?         boolean
      |  |  +--ro  +---w (nexthop-type)?
      |  |     +--:(nexthop-base)
      |  |     |  ...
      |  |     +--:(nexthop-chain) {nexthop-chain}?
      |  |     |  ...
      |  |     +--:(nexthop-replicates) {nexthop-replicates}?
      |  |     |  ...
      |  |     +--:(nexthop-protection) {nexthop-protection}?
      |  |     |  ...
      |  |     +--:(nexthop-load-balance) {nexthop-load-balance}?
      |  |        ...
      |  +--ro output
      |     +--ro result        boolean        uint32
      |     +--ro nexthop-id reason?       string
      |     +--ro nexthop-id?   uint32
      +---x nh-delete
       +--ro
         +---w input
         |  +--ro  +---w rib-name              string
         |  +--ro nexthop-id  +---w nexthop-id?           uint32
         |  +--ro sharing-flag  +---w sharing-flag?         boolean
         |  +--ro  +---w (nexthop-type)?
         |     +--:(nexthop-base)
         |     |  ...
         |     +--:(nexthop-chain) {nexthop-chain}?
         |     |  ...
         |     +--:(nexthop-replicates) {nexthop-replicates}?
         |     |  ...
         |     +--:(nexthop-protection) {nexthop-protection}?
         |     |  ...
         |     +--:(nexthop-load-balance) {nexthop-load-balance}?
         |        ...
         +--ro output
            +--ro result boolean uint32
            +--ro reason? string
   notifications:
      +---n nexthop-resolution-status-change
      |  +--ro nexthop
      |  |  +--ro nexthop-id nexthop-id?           uint32
      |  |  +--ro sharing-flag sharing-flag?         boolean
      |  |  +--ro (nexthop-type)?
      |  |     +--:(nexthop-base)
      |  |     |  ...

      |  |     +--:(nexthop-chain) {nexthop-chain}?
      |  |     |  ...
      |  |     +--:(nexthop-replicates) {nexthop-replicates}?
      |  |     |  ...
      |  |     +--:(nexthop-protection) {nexthop-protection}?
      |  |     |  ...
      |  |     +--:(nexthop-load-balance) {nexthop-load-balance}?
      |  |        ...
      |  +--ro nexthop-state nexthop-state-def
      +---n route-change
         +--ro rib-name                 string
         +--ro rib-family               rib-family-def
         +--ro route-index              uint64
         +--ro match
         |  +--ro (route-type)?
         |     +--:(ipv4)
         |     |  ...
         |     +--:(ipv6)
         |     |  ...
         |     +--:(mpls-route)
         |     |  ...
         |     +--:(mac-route)
         |     |  ...
         |     +--:(interface-route)
         |        ...
         +--ro route-installed-state route-installed-state-def
         +--ro route-state         route-state-def
         +--ro route-change-reason route-reason-def

         Figure 1: Overview of I2RS Rib Module Structure

2.1.  RIB Capability

   RIB capability negotiation is very important because not all of the
   hardware will be able to support all kinds of nexthops and there
   should be a limitation on how many levels of lookup can be
   practically performed.  Therefore, a RIB data model MUST specify a
   way for an external entity to learn about the functional capabilities
   of a network device.

   At the same time, nexthop chains can be used to specify multiple
   headers over a packet, before that particular packet is forwarded.
   Not every network device will be able to support all kinds of nexthop
   chains along with the arbitrary number of headers which are chained
   together.  The RIB data model MUST provide a way to expose the
   nexthop chaining capability supported by a given network device.

   This module uses the feature and if-feature statements to achieve
   above capability negotiation.

2.2.  Routing Instance and Rib

   A routing instance, in the context of the RIB information model, is a
   collection of RIBs, interfaces, and routing protocol parameters.  A
   routing instance creates a logical slice of the router and can allow
   multiple different logical slices; across a set of routers; to
   communicate with each other.  And the routing protocol parameters
   control the information available in the RIBs.  More detail about
   routing instance can be found in Section 2.2 of
   [I-D.ietf-i2rs-rib-info-model].

   As described in [I-D.ietf-i2rs-rib-info-model], there will be
   multiple routing instances for a router.  At the same time, for

   For a routing instance, there would will be multiple RIBs as well. RIBs.  Therefore, this
   model uses "list" to express the RIBs.  The structure tree is shown
   as following figure.

   +--rw routing-instance
      +--rw name              string
      +--rw interface-list* [name]
      |  +--rw name if:interface-ref
      +--rw router-id?        yang:dotted-quad
      +--rw lookup-limit?     uint8
      +--rw rib-list* [name]
         +--rw name            string
         +--rw rib-family      rib-family-def
         +--rw ip-rpf-check?   boolean
         +--rw route-list* [route-index]
            ... (refer to Section 2.3)

       Figure 2: Routing Instance Stuture Structure

2.3.  Route

   A route is essentially a match condition and an action following that
   match.  The match condition specifies the kind of route (e.g., IPv4,
   MPLS, MAC, Interface etc.) and the set of fields to match on.

   According to the definition in [I-D.ietf-i2rs-rib-info-model], a
   route MUST associate with the following attributes:

   o  ROUTE_PREFERENCE: See Section 2.3 of
      [I-D.ietf-i2rs-rib-info-model].

   o  ACTIVE: Indicates whether a route is fully resolved and is a
      candidate for selection.

   o  INSTALLED: Indicates whether the route got installed in the FIB.

   In addition, a route can associate with one or more optional route
   attributes(e.g., route-vendor-attributes).

   For a RIB, there will have a number of routes, so the routes are
   expressed as a list under the a specific rib.  Each rib has its own route
   list.

   +--rw route-list* [route-index]
      +--rw route-index                uint64
      +--rw match
      |  +--rw (route-type)?
      |     +--:(ipv4)
      |     |  +--rw ipv4
      |     |     +--rw (ip-route-match-type)?
      |     |        +--:(dest-ipv4-address)
      |     |        |  ...
      |     |        +--:(src-ipv4-address)
      |     |        |  ...
      |     |        +--:(dest-src-ipv4-address)
      |     |           ...
      |     +--:(ipv6)
      |     |  +--rw ipv6
      |     |     +--rw (ip-route-match-type)?
      |     |        +--:(dest-ipv6-address)
      |     |        |  ...
      |     |        +--:(src-ipv6-address)
      |     |        |  ...
      |     |        +--:(dest-src-ipv6-address)
      |     |           ...
      |     +--:(mpls-route)
      |     |  +--rw mpls-label              uint32
      |     +--:(mac-route)
      |     |  +--rw mac-address             uint32
      |     +--:(interface-route)
      |        +--rw interface-identifier if:interface-ref
      +--rw nexthop
      |  ...(refer to Section 2.4)

                  Figure 3: Routes Structure

2.4.  Nexthop

   A nexthop represents an object resulting from a route lookup.  As
   illustrated in Section 2.4 of [I-D.ietf-i2rs-rib-info-model], to
   support various of use cases (e.g., load balance, protection,
   multicast or the combination of them), the nexthop is modelled as a
   multi-level structure and supports recursion.  The first level of the
   nexthop includes the following four types:

   o  Base: The "base" nexthop itself is a hierarchical structure, it is the base foundation of all other nexthop
      types.  The first level of the base
      nexthop  It includes special-nexthop and nexthop-chain.  The nexthop-
      chain can have one or more nexthop chain members, each member is
      one of the four types (as listed below) of specific nexthop.

      Other first level nexthop (e.g., load-balance, protection and
      replicate) will finally be iterated to a "base" nexthop. follow basic nexthops:

      *  nexthop-id

      *  IPv4 address

      *  IPv6 address

      *  egress-interface

      *  egress-interface with IPv4 address

      *  egress-interface with IPv6 address

      *  egress-interface with MAC address

      *  logical-tunnel

      *  tunnel-encap

      *  tunnel-decap

      *  rib-name

   o  Chain:Provide a way to perform multiple operations on a packet by
      logically combining them.

   o  Load-balance: Designed for load-balance case where it normally
      will have multiple weighted nexthops.

   o  Protection: Designed for protection scenario where it normally
      will have primary and standby nexthop.

   o  Replicate: Designed for multiple destinations forwarding.

   The structure tree of nexthop is shown in the following figures.

   +--rw nexthop
   |  +--rw nexthop-id nexthop-id?           uint32
   |  +--rw sharing-flag sharing-flag?         boolean
   |  +--rw (nexthop-type)?
   |     +--:(nexthop-base)
   |     |  ...(refer to Figure 5)
   |     +--:(nexthop-chain) {nexthop-chain}?
   |     |  +--rw nexthop-chain
   |     |     +--rw nexthop-list* [nexthop-member-id]
   |     |        +--rw nexthop-member-id uint32
   |     +--:(nexthop-replicates) {nexthop-replicates}?
   |     |  +--rw nexthop-replicates
   |     |     +--rw nexthop-list* [nexthop-member-id]
   |     |        +--rw nexthop-member-id uint32
   |     +--:(nexthop-protection) {nexthop-protection}?
   |     |  +--rw nexthop-protection
   |     |     +--rw nexthop-list* [nexthop-member-id]
   |     |        +--rw nexthop-member-id uint32
   |     |        +--rw nexthop-preference nexthop-preference-def
   |     +--:(nexthop-load-balance) {nexthop-load-balance}?
   |        +--rw nexthop-lbs
   |           +--rw nexthop-list* [nexthop-member-id]
   |              +--rw nexthop-member-id uint32
   |              +--rw nexthop-lb-weight nexthop-lb-weight-def

                       Figure 4: Nexhop Nexthop Structure

   Figure 5 (as shown blow) is a sub-tree of nexthop, it's under the
   nexthop base node. node and shows that structure of the "base" nexthop.

 +--:(nexthop-base)
 |  +--rw nexthop-base
 |     +--rw (nexthop-base-type)?
 |        +--:(special-nexthop)
 |        |  +--rw special? special-nexthop-def
 |        +--:(egress-interface-nexthop)
 |        |  +--rw outgoing-interface if:interface-ref
 |        +--:(ipv4-address-nexthop)
 |        |  +--rw ipv4-address inet:ipv4-address
 |        +--:(ipv6-address-nexthop)
 |        |  +--rw ipv6-address inet:ipv6-address
 |        +--:(egress-interface-ipv4-nexthop)
 |        |  +--rw egress-interface-ipv4-address
 |        |     +--rw outgoing-interface if:interface-ref
 |        |     +--rw ipv4-address       inet:ipv4-address
 |        +--:(egress-interface-ipv6-nexthop)
 |        |  +--rw egress-interface-ipv6-address
 |        |     +--rw outgoing-interface if:interface-ref
 |        |     +--rw ipv6-address       inet:ipv6-address
 |        +--:(egress-interface-mac-nexthop)
 |        |  +--rw egress-interface-mac-address
 |        |     +--rw outgoing-interface if:interface-ref
 |        |     +--rw ieee-mac-address uint32
 |        +--:(tunnel-encap-nexthop) {nexthop-tunnel}?
 |        |  +--rw tunnel-encap
 |        |     +--rw (tunnel-type)?
 |        |        +--:(ipv4) {ipv4-tunnel}?
 |        |        |  +--rw ipv4-header
 |        |        |     +--rw src-ipv4-address inet:ipv4-address
 |        |        |     +--rw dest-ipv4-address inet:ipv4-address
 |        |        |     +--rw protocol          uint8
 |        |        |     +--rw ttl?              uint8
 |        |        |     +--rw dscp?             uint8
 |        |        +--:(ipv6) {ipv6-tunnel}?
 |        |        |  +--rw ipv6-header
 |        |        |     +--rw src-ipv6-address inet:ipv6-address
 |        |        |     +--rw dest-ipv6-address inet:ipv6-address
 |        |        |     +--rw next-header       uint8
 |        |        |     +--rw traffic-class? uint8
 |        |        |     +--rw flow-label?       uint16
 |        |        |     +--rw hop-limit?        uint8
 |        |        +--:(mpls) {mpls-tunnel}?
 |        |        |  +--rw mpls-header
 |        |        |     +--rw label-operations* [label-oper-id]
 |        |        |        +--rw label-oper-id uint32
 |        |        |        +--rw (label-actions)?
 |        |        |           +--:(label-push)
 |        |        |           |  +--rw label-push
 |        |        |           |     +--rw label        uint32
 |        |        |           |     +--rw s-bit?       boolean
 |        |        |           |     +--rw tc-value? uint8
 |        |        |           |     +--rw ttl-value? uint8
 |        |        |           +--:(label-swap)
 |        |        |              +--rw label-swap
 |        |        |                 +--rw in-label      uint32
 |        |        |                 +--rw out-label     uint32
 |        |        |                 +--rw ttl-action? ttl-action-def
 |        |        +--:(gre) {gre-tunnel}?
 |        |        |  +--rw gre-header
 |        |        |     +--rw (dest-address-type)?
 |        |        |     |  +--:(ipv4)
 |        |        |     |  |  +--rw ipv4-dest inet:ipv4-address
 |        |        |     |  +--:(ipv6)
 |        |        |     |     +--rw ipv6-dest inet:ipv6-address
 |        |        |     +--rw protocol-type uint16
 |        |        |     +--rw key?          uint64
 |        |        +--:(nvgre) {nvgre-tunnel}?
 |        |        |  +--rw nvgre-header
 |        |        |     +--rw (nvgre-type)?
 |        |        |     |  +--:(ipv4)
 |        |        |     |  |  +--rw src-ipv4-address inet:ipv4-address
 |        |        |     |  |  +--rw dest-ipv4-address inet:ipv4-address
 |        |        |     |  |  +--rw protocol          uint8
 |        |        |     |  |  +--rw ttl?              uint8
 |        |        |     |  |  +--rw dscp?             uint8
 |        |        |     |  +--:(ipv6)
 |        |        |     |     +--rw src-ipv6-address inet:ipv6-address
 |        |        |     |     +--rw dest-ipv6-address inet:ipv6-address
 |        |        |     |     +--rw next-header       uint8
 |        |        |     |     +--rw traffic-class?    uint8
 |        |        |     |     +--rw flow-label?       uint16
 |        |        |     |     +--rw hop-limit?        uint8
 |        |        |     +--rw virtual-subnet-id uint32
 |        |        |     +--rw flow-id?          uint16
 |        |        +--:(vxlan) {vxlan-tunnel}?
 |        |           +--rw vxlan-header
 |        |              +--rw (vxlan-type)?
 |        |              |  +--:(ipv4)
 |        |              |  |  +--rw src-ipv4-address inet:ipv4-address
 |        |              |  |  +--rw dest-ipv4-address inet:ipv4-address
 |        |              |  |  +--rw protocol             uint8
 |        |              |  |  +--rw ttl?                 uint8
 |        |              |  |  +--rw dscp?                uint8
 |        |              |  +--:(ipv6)
 |        |              |     +--rw src-ipv6-address inet:ipv6-address
 |        |              |     +--rw dest-ipv6-address inet:ipv6-address
 |        |              |     +--rw next-header          uint8
 |        |              |     +--rw traffic-class?       uint8
 |        |              |     +--rw flow-label?          uint16
 |        |              |     +--rw hop-limit?           uint8
 |        |              +--rw vxlan-identifier     uint32
 |        +--:(tunnel-decap-nexthp)        +--:(tunnel-decap-nexthop) {nexthop-tunnel}?
 |        |  +--rw tunnel-decap
 |        |     +--rw (tunnel-type)?
 |        |        +--:(ipv4) {ipv4-tunnel}?
 |        |        |  +--rw ipv4-decap
 |        |        |     +--rw ipv4-decap tunnel-decap-action-def
 |        |        |     +--rw ttl-action?   ttl-action-def
 |        |        +--:(ipv6) {ipv6-tunnel}?
 |        |        |  +--rw ipv6-decap
 |        |        |     +--rw ipv6-decap tunnel-decap-action-def
 |        |        |     +--rw hop-limit-action? hop-limit-action-def
 |        |        +--:(mpls) {mpls-tunnel}?
 |        |           +--rw label-pop
 |        |              +--rw label-pop     mpls-label-action-def
 |        |              +--rw ttl-action?   ttl-action-def
 |        +--:(logical-tunnel-nexthop) {nexthop-tunnel}?
 |        |  +--rw logical-tunnel
 |        |     +--rw tunnel-type tunnel-type-def
 |        |     +--rw tunnel-name string
 |        +--:(rib-name-nexthop)
 |        |  +--rw rib-name?                        string
 |        +--:(nexthop-identifier)
 |           +--rw nexthop-ref                      nexthop-ref

                 Figure 5: Nexthop Base Structure

2.5.  RPC Operations

   This module defines the following RPC operations:

   o  rib-add: It is defined to add a rib to a routing instance.  A name
      of the rib, address family of the rib and whether the RPF check is
      enabled are passed as the input parameters.  The output is the
      result of the add operation: 1 means success, and 0 means failed.

      *  true - success;

      *  false - failed; when failed, the i2rs agent may return the
         specific reason that causes the failure.

   o  rib-delete: It is defined to delete a rib from a routing instance.
      When a rib is deleted, all routes installed in the rib will be
      deleted.  A name of the rib is passed as the input parameter.  The
      output is the result of the delete operation: 1 means success, and
      0 means failed.

      *  true - success;

      *  false - failed; when failed, the i2rs agent may return the
         specific reason that causes the failure.

   o  route-add: It is defined to add a route or a set of routes to a
      rib.  A rib name, the route prefix(es), route attributes, route
      vendor attributes and attributes, nexthop and whether return failure detail are
      passed as the input parameters.
      The output is the result of the add operation: 1 means success,
      and 0 means failed.  Before calling the route-add rpc,
      it is required to call the nh-add rpc to create and/or return the
      nexthop identifier.  The output is a combination of the route
      operation states that include:

      *  success-count: the numbers of routes that are successfully
         added;

      *  failed-count: the numbers of the routes that are failed to be
         added;

      *  failure-detail: shows the specific failed routes that failure
         reason.

   o  route-delete: It is defined to delete a route or a set of routes
      from a rib.  A name of the rib and rib, the route prefix(es) and whether
      return failure detail are passed as the input parameters.  The
      output is combination of the result route operation states that include:

      *  success-count: the numbers of routes that are successfully
         deleted;

      *  failed-count: the delete
      operation: 1 means success, and 0 means failed. numbers of the routes that are failed to be
         deleted;

      *  failure-detail: shows the specific failed routes that failure
         reason.

   o  route-update: It is defined to update a route or a set of routes.
      A rib name, the route prefix(es), or route attributes, or route
      vendor attributes, or nexthop are passed as the input parameters.
      The match conditions can be either route prefix(es), or route
      attributes, or route vendor attributes, or nexthop.  The update
      actions include: update the nexthop, update the route attributes,
      update the route vendor attributes.  The output is combination of
      the result route operation states that include:

      *  success-count: the numbers of routes that are successfully
         updated;

      *  failed-count: the update operation: 1 means success, and 0 means failed. numbers of the routes that are failed to be
         updated;

      *  failure-detail: shows the specific failed routes that failure
         reason.

   o  nh-add: It is defined to add a nexthop to a rib.  A name of the
      rib and a nexthop are passed as the input parameters.  The network
      node is required to allocate a nexhop nexthop identifier to the nexthop.
      The outputs include the result of the update operation (1 means nexthop add operation.

      *  true - success; when success, and 0 means failed ) and the a nexthop identifier that is
      allocated will be
         returned to the nexthop. i2rs client.

      *  false - failed; when failed, the i2rs agent may return the
         specific reason that causes the failure.

   o  nh-delete: It is defined to delete a nexthop from a rib.  A name
      of a rib and a nexthop or nexthop identifier are passed as the
      input parameters.  The output is the result of the delete
      operation: 1 means success, 0 means failed.

   The

      *  true - success;

      *  false - failed; when failed, the i2rs agent may return the
         specific reason that causes the failure.

   The structure tree of rpcs is showing in following figure.

   rpcs:
      +---x rib-add
      |  +--ro  +---w input
      |  |  +--ro  +---w rib-name        string
      |  |  +--ro  +---w rib-family      rib-family-def
      |  |  +--ro  +---w ip-rpf-check?   boolean
      |  +--ro output
      |     +--ro result boolean uint32
      |     +--ro reason? string
      +---x rib-delete
      |  +--ro  +---w input
      |  |  +--ro  +---w rib-name string
      |  +--ro output
      |     +--ro result boolean uint32
      |     +--ro reason? string
      +---x route-add
      |  +--ro  +---w input
      |  |  +--ro  +---w return-failure-detail?   boolean
      |  |  +---w rib-name                 string
      |  |  +--ro  +---w routes
      |  |     +--ro     +---w route-list* [route-index]
      |  |        ...
      |  +--ro output
      |     +--ro result boolean success-count     uint32
      |     +--ro failed-count      uint32
      |     +--ro failure-detail
      |        +--ro failed-routes* [route-index]
      |           +--ro route-index uint32
      |           +--ro error-code? uint32
      +---x route-delete
      |  +--ro  +---w input
      |  |  +--ro  +---w return-failure-detail?   boolean
      |  |  +---w rib-name                 string
      |  |  +--ro  +---w routes
      |  |     +--ro     +---w route-list* [route-index]
      |  |        ...

      |  +--ro output
      |     +--ro result boolean success-count     uint32
      |     +--ro failed-count      uint32
      |     +--ro failure-detail
      |        +--ro failed-routes* [route-index]
      |           +--ro route-index uint32
      |           +--ro error-code? uint32
      +---x route-update
      |  +--ro  +---w input
      |  |  +--ro  +---w return-failure-detail?           boolean
      |  |  +---w rib-name                         string
      |  |  +--ro (match-conditions)?  +---w (match-options)?
      |  |     +--:(match-route-prefix)
      |  |     |  ...
      |  |     +--:(match-route-attributes)
      |  |     |  ...
      |  |     +--:(match-route-vendor-attributes) {..vendor-attributes}? {...}?
      |  |     |  ...
      |  |     +--:(match-nexthop)
      |  |        ...
      |  +--ro output
      |     +--ro result boolean success-count uint32
      |     +--ro failed-count uint32
      |     +--ro failure-detail
      |        +--ro failed-routes* [route-index]
      |           +--ro route-index uint32
      |           +--ro error-code? uint32
      +---x nh-add
      |  +--ro  +---w input
      |  |  +--ro  +---w rib-name              string
      |  |  +--ro nexthop-id  +---w nexthop-id?           uint32
      |  |  +--ro sharing-flag  +---w sharing-flag?         boolean
      |  |  +--ro  +---w (nexthop-type)?
      |  |     ...
      |  +--ro output
      |     +--ro result        boolean        uint32
      |     +--ro nexthop-id reason?       string
      |     +--ro nexthop-id?   uint32
      +---x nh-delete
        +--ro
         +---w input
         |  +--ro  +---w rib-name              string
         |  +--ro nexthop-id  +---w nexthop-id?           uint32
         |  +--ro sharing-flag  +---w sharing-flag?         boolean
         |  +--ro  +---w (nexthop-type)?
         |     ...
         +--ro output
            +--ro result boolean uint32
            +--ro reason? string
              Figure 6: RPCs Structure

2.6.  Notifications

   Asynchronous notifications are sent by the RIB manager of a network
   device to an external entity when some event triggers on the network
   device.  A RIB data-model MUST support sending 2 kind of asynchronous
   notifications.

   1.  Route change notification:

   o Installed (Indicates whether the route got installed in the FIB) ;

   o Active (Indicates whether a route is fully resolved and is a
   candidate for selection) ;

   o Reason - E.g.  Not authorized

   2.  Nexthop resolution status notification

   Nexthops can be fully resolved nexthops or an unresolved nexthop.

   A resolved nexthop has adequate level of information to send the
   outgoing packet towards the destination by forwarding it on an
   interface of a directly connected neighbor.

   An unresolved nexthop is something that requires the RIB manager to
   determine the final resolved nexthop.  For example, in a case when a
   nexthop could be an IP address.  The RIB manager would resolve how to
   reach that IP address, e.g. by checking if that particular IP is
   address reachable by regular IP forwarding or by a MPLS tunnel or by
   both.  If the RIB manager cannot resolve the nexthop, then the
   nexthop remains in an unresolved state and is NOT a suitable
   candidate for installation in the FIB.

   The structure tree of notifications is shown in the following figure.

   notifications:
         +---n nexthop-resolution-status-change
         |  +--ro nexthop
         |  |  +--ro nexthop-id            uint32
         |  |  +--ro sharing-flag          boolean
         |  |  +--ro (nexthop-type)?
         |  |     +--:(nexthop-base)
         |  |     |  ...
         |  |     +--:(nexthop-chain) {nexthop-chain}?
         |  |     |  ...
         |  |     +--:(nexthop-replicates) {nexthop-replicates}?
         |  |     |  ...
         |  |     +--:(nexthop-protection) {nexthop-protection}?
         |  |     |  ...
         |  |     +--:(nexthop-load-balance) {nexthop-load-balance}?
         |  |        ...
         |  +--ro nexthop-state nexthop-state-def
         +---n route-change
            +--ro rib-name                 string
            +--ro rib-family               rib-family-def
            +--ro route-index              uint64
            +--ro match
            |  +--ro (route-type)?
            |     +--:(ipv4)
            |     |  ...
            |     +--:(ipv6)
            |     |  ...
            |     +--:(mpls-route)
            |     |  ...
            |     +--:(mac-route)
            |     |  ...
            |     +--:(interface-route)
            |        ...
            +--ro route-installed-state route-installed-state-def
            +--ro route-state              route-state-def
            +--ro route-change-reason      route-reason-def

                       Figure 7: Notifications Structure

3.  YANG Modules

   //<CODE

   <CODE BEGINS> file "ietf i2rs rib@2015-10-28.yang" "ietf-i2rs-rib@2015-11-20.yang"

   module ietf-i2rs-rib {
     namespace "urn:ietf:params:xml:ns:yang:ietf-i2rs-rib";
     // replace with iana namespace when assigned
     prefix "iir";
     import ietf-inet-types {
       prefix inet;
       //rfc6991
     }

     import ietf-interfaces {
       prefix "if";
     }

     import ietf-yang-types {
       prefix yang;
     }

     organization
       "IETF I2RS (Interface to Routing System) Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/i2rs/>
        WG List:  <mailto:i2rs@ietf.org>

        WG Chair: Susan Hares
                  <mailto:shares@ndzh.com>

        WG Chair: Jeffrey Haas
                  <mailto:jhaas@pfrc.org>

        Editor:   Lixing Wang
                  <mailto:wang_little_star@sina.com>

        Editor:   Hariharan Ananthakrishnan
                  <mailto:hari@packetdesign.com>

        Editor:   Mach(Guoyi) Chen
                  <mailto:mach.chen@huawei.com>

        Editor:   Amit Dass
                  <mailto:amit.dass@ericsson.com>

        Editor:   Sriganesh Kini
                  <mailto:sriganesh.kini@ericsson.com>

        Editor:   Nitin Bahadur
                  <mailto:nitin_bahadur@yahoo.com>";
     description
       "This module defines a YANG data model for
        Routing Information Base (RIB) that aligns
        with the I2RS RIB information model.";
     revision "2015-10-28" "2015-11-20" {
       description "initial revision";
       reference "draft-ietf-i2rs-rib-info-model-08"; "draft-ietf-i2rs-data-model-04";
     }

     //Features
     feature nexthop-tunnel {
       description
         "This feature means that a node support
          tunnel nexhtop nexthop capability.";
     }

     feature nexthop-chain {
       description
         "This feature means that a node support
          chain nexhtop nexthop capability.";
     }

     feature nexthop-protection {
       description
         "This feature means that a node support
          protection nexhtop nexthop capability.";
     }

     feature nexthop-replicates {
       description
         "This feature means that a node support
          relicates nexhtop nexthop capability.";
     }

     feature nexthop-load-balance {
       description
         "This feature means that a node support
          load balance nexhtop nexthop capability.";
     }

     feature ipv4-tunnel {
       description
         "This feature means that a node support
          IPv4 tunnel encapsulation capability.";
     }

     feature ipv6-tunnel {
       description
         "This feature means that a node support
          IPv6 tunnel encapsulation capability.";
     }

     feature mpls-tunnel {
       description
         "This feature means that a node support
          MPLS tunnel encapsulation capability.";
     }

     feature vxlan-tunnel {
       description
         "This feature means that a node support
          VxLAN tunnel encapsulation capability.";
     }

     feature gre-tunnel {
       description
         "This feature means that a node support
          GRE tunnel encapsulation capability.";
     }

     feature nvgre-tunnel {
       description
         "This feature means that a node support
          NvGRE tunnel encapsulation capability.";
     }

     feature route-vendor-attributes {
       description
         "This feature means that a node support
          route vendor attributes.";
     }

     //Identities and Type Definitions
     identity mpls-label-action {
       description
         "Base identify from which all mpls label
          operations are derived.
          The MPLS label stack operations include:
          push - to add a new label to a label stack,
          pop - to pop the top label from a label stack,
          swap - to change the top label of a label
                 stack with new label.";
     }

     identity label-push {
       base "mpls-label-action";
        description
         "MPLS label stack operation: push.";
     }

     identity label-pop {
       base "mpls-label-action";
       description
         "MPLS label stack operation: pop.";
     }

     identity label-swap {
       base "mpls-label-action";
       description
         "MPLS label stack operation: swap.";
     }

     typedef mpls-label-action-def {
       type identityref {
         base "mpls-label-action";
       }
       description
         "MPLS label action def.";
     }

     identity tunnel-decap-action {
       description
         "Base identify from which all tunnel decap
          actions are derived.
          Tunnel decap actions include:
          ipv4-decap - to decap an IPv4 tunnel,
          ipv6-decap - to decap an IPv6 tunnel.";
     }

     identity ipv4-decap {
       base "tunnel-decap-action";
       description
         "IPv4 tunnel decap.";
     }

     identity ipv6-decap {
       base "tunnel-decap-action";
       description
         "IPv4 tunnel decap.";
     }

     typedef tunnel-decap-action-def {
       type identityref {
         base "tunnel-decap-action";
       }
       description
         "Tunnel decap def.";
     }

     identity ttl-action {
       description
         "Base identify from which all TTL
          actions are derived.
          The tll actions include:
           - ttl-no-action: do nothing regarding the TTL, or
           - ttl-copy-to-inner: copy the TTL of the outer
             header to inner header, or
           - ttl-decrease-and-copy-to-inner: Decrease the TTL
             by one and copy it to inner header."; derived.";
     }

     identity no-action {
       base "ttl-action";
       description
         "Do nothing regarding the TTL.";
     }

     identity copy-to-inner {
       base "ttl-action";
       description
         "Copy the TTL of the outer header
          to inner header.";
     }

     identity decrease-and-copy-to-inner {
       base "ttl-action";
       description
         "Decrease TTL by one and copy the TTL
          to inner header.";
     }

     identity decrease-and-copy-to-next {
       base "ttl-action";
       description
         "Decrease TTL by one and copy the TTL
          to the next header.For example: when
          MPLS label swapping, decrease the TTL
          of the in label and copy it to the out
          label.";
     }

     typedef ttl-action-def {
       type identityref {
         base "ttl-action";
       }
       description
         "TTL action def.";
     }

     identity hop-limit-action {
       description
         "Base identify from which all hop limit
          actions are derived.";
     }
     identity hop-limit-no-action {
       base "hop-limit-action";
       description
         "Do nothing regarding the hop limit.";
     }

     identity hop-limit-copy-to-inner {
       base "hop-limit-action";
       description
         "Copy the hop limit of the outer header
          to inner header.";
     }

     typedef hop-limit-action-def {
       type identityref {
         base "hop-limit-action";
       }
       description
         "IPv6 hop limit action def.";
     }

     identity special-nexthop {
       description
         "Base identify from which all special
          nexthops are derived.";
     }

     identity discard {
       base "special-nexthop";
       description
         "This indicates that the network
          device should drop the packet and
          increment a drop counter.";
     }

     identity discard-with-error {
       base "special-nexthop";
       description
         "This indicates that the network
          device should drop the packet,
          increment a drop counter and send
          back an appropriate error message
          (like ICMP error).";
     }

     identity receive {
       base "special-nexthop";
       description
         "This indicates that that the traffic is
          destined for the network device.  For
          example, protocol packets or OAM packets.
          All locally destined traffic SHOULD be
          throttled to avoid a denial of service
          attack on the router's control plane. An
          optional rate-limiter can be specified
          to indicate how to throttle traffic
          destined for the control plane.";
     }

     identity cos-value {
       base "special-nexthop";
       description
         "Cos-value special nexthop.";
     }

     typedef special-nexthop-def {
       type identityref {
         base "special-nexthop";
       }
       description
         "Special nexthop def.";
     }

     identity ip-route-match-type {
       description
         "Base identify from which all route
          match types are derived.
          Route match type could be:
          match source, or
          match destination, or
          match source and destination.";
     }

     identity match-ip-src {
       base "ip-route-match-type";
       description
         "Source route match type.";
     }
     identity match-ip-dest {
       base "ip-route-match-type";
       description
         "Destination route match type";
     }
     identity match-ip-src-dest {
       base "ip-route-match-type";
       description
         "Src and Dest route match type";
     }

     typedef ip-route-match-type-def {
       type identityref {
         base "ip-route-match-type";
       }
       description
         "IP route match type def.";
     }

     identity rib-family {
       description
         "Base identify from which all rib
          address families are derived.";
     }

     identity ipv4-rib-family {
       base "rib-family";
       description
         "IPv4 rib address family.";
     }

     identity ipv6-rib-family {
       base "rib-family";
       description
         "IPv6 rib address family.";
     }

     identity mpls-rib-family {
       base "rib-family";
       description
         "MPLS rib address family.";
     }

     identity ieee-mac-rib-family {
       base "rib-family";
       description
         "MAC rib address family.";
     }

     typedef rib-family-def {
       type identityref {
         base "rib-family";
       }
       description
         "Rib address family def.";
     }
     identity route-type {
       description
         "Base identify from which all route types
          are derived.";
     }

     identity ipv4-route {
       base "route-type";
       description
         "IPv4 route type.";
     }

     identity ipv6-route {
       base "route-type";
       description
         "IPv6 route type.";
     }

     identity mpls-route {
       base "route-type";
       description
         "MPLS route type.";
     }

     identity ieee-mac {
       base "route-type";
       description
         "MAC route type.";
     }

     identity interface {
       base "route-type";
       description
         "Interface route type.";
     }

     typedef route-type-def {
       type identityref {
         base "route-type";
       }
       description
         "Route type def.";
     }

     identity tunnel-type {
       description
         "Base identify from which all tunnel
          types are derived.";

     }

     identity ipv4-tunnel {
       base "tunnel-type";
       description
         "IPv4 tunnel type";
     }

     identity ipv6-tunnel {
       base "tunnel-type";
       description
         "IPv6 Tunnel type";
     }

     identity mpls-tunnel {
       base "tunnel-type";
       description
         "MPLS tunnel type";
     }

     identity gre-tunnel {
       base "tunnel-type";
       description
         "GRE tunnel type";
     }

     identity vxlan-tunnel {
       base "tunnel-type";
       description
         "VxLAN tunnel type";
     }

     identity nvgre-tunnel {
       base "tunnel-type";
       description
         "NVGRE tunnel type";
     }

     typedef tunnel-type-def {
       type identityref {
         base "tunnel-type";
       }
       description
         "Tunnel type def.";
     }

     identity route-state {
       description
         "Base identify from which all route
          states are derived.";
     }

     identity active {
       base "route-state";
       description
         "Active state.";
     }

     identity inactive {
       base "route-state";
       description
         "Inactive state.";
     }

     typedef route-state-def {
       type identityref {
         base "route-state";
       }
       description
         "Route state def.";
     }

     identity nexthop-state {
       description
         "Base identify from which all nexthop
          states are derived.";
     }

     identity resolved {
       base "nexthop-state";
       description
         "Reolved nexthop state.";
     }

     identity unresolved {
       base "nexthop-state";
       description
         "Unresolved nexthop state.";
     }

     typedef nexthop-state-def {
       type identityref {
         base "nexthop-state";
       }
       description
         "Nexthop state def.";

     }

     identity route-installed-state {
       description
         "Base identify from which all route
          installed states are derived.";
     }

     identity uninstalled {
       base "route-installed-state";
       description
         "Uninstalled state.";
     }

     identity installed {
       base "route-installed-state";
       description
         "Installed state.";
     }

     typedef route-installed-state-def {
       type identityref {
         base "route-installed-state";
       }
       description
         "Route installed state def.";
     }

     identity route-reason {
       description
         "Base identify from which all route
          reasons are derived.";
     }

     identity low-preference {
       base "route-reason";
       description
         "Low preference";
     }

     identity unresolved-nexthop {
       base "route-reason";
       description
         "Unresolved nexthop";
     }

     identity higher-metric {
       base "route-reason";
       description
         "Higher metric";
     }

     typedef route-reason-def {
       type identityref {
         base "route-reason";
       }
       description
         "Route reason def.";
     }

     typedef nexthop-preference-def {
       type uint8 {
         range "1..99";
       }
       description
         "Nexthop-preference is used for protection schemes.
          It is an integer value between 1 and 99.  A lower
          value indicates higher preference. To download a
          primary/standby/tertiary group N
          nexthops to the FIB, the N nexthops that are resolved and have two highest
          preferences with the lowest
          value are selected.";
     }
     typedef nexthop-lb-weight-def {
       type uint8 {
         range "1..99";
       }
       description
         "Nhop-lb-weight is a number between 1 and 99.";
     }

     typedef nexthop-ref {
       type leafref {
         path  "/iir:routing-instance" +
               "/iir:rib-list" +
               "/iir:route-list" +
               "/iir:nexthop" +
               "/iir:nexthop-id";
       }
       description
         "A nexthop reference that provides
          an indirection reference to a nexthop.";
     }

     //Groupings
     grouping route-prefix {
       description
         "The common attributes used for all types of route prefix.";
       leaf route-index {
         type uint64 ;
         mandatory true;
         description
           "Route index.";
       }
       container match {
         description
           "The match condition specifies the
            kind of route (IPv4, MPLS, etc.)
            and the set of fields to match on.";
         choice route-type {
           description
             "Route types: IPv4, IPv6, MPLS, MAC etc.";
           case ipv4 {
             description
               "IPv4 route case.";
             container ipv4 {
               description
                 "IPv4 route match.";
               choice ip-route-match-type {
                 description
                   "IP route match type options:
                    match source, or
                    match destination, or
                    match source and destination.";
                 case dest-ipv4-address {
                   leaf dest-ipv4-prefix {
                     type inet:ipv4-prefix;
                     mandatory true;
                     description
                       "An IPv4 destination address as the match.";
                   }
                 }
                 case src-ipv4-address {
                   leaf src-ipv4-prefix {
                     type inet:ipv4-prefix;
                     mandatory true;
                     description
                       "An IPv4 source address as the match.";
                   }
                 }
                 case dest-src-ipv4-address {
                   container dest-src-ipv4-address {
                     description
                       "A combination of an IPv4 source and
                        an IPv4 destination address as the match.";

                     leaf dest-ipv4-prefix {
                       type inet:ipv4-prefix;
                       mandatory true;
                       description
                         "The IPv4 destination address of the match.";
                     }
                     leaf src-ipv4-prefix {
                       type inet:ipv4-prefix;
                       mandatory true;
                       description
                         "The IPv4 source address of the match";
                     }
                   }
                 }
               }
             }
           }
           case ipv6 {
             description
               "IPv6 route case.";
             container ipv6 {
               description
                 "IPv6 route match.";
               choice ip-route-match-type {
                 description
                   "IP route match type options:
                    match source, or
                    match destination, or
                    match source and destination.";
                 case dest-ipv6-address {
                   leaf dest-ipv6-prefix {
                     type inet:ipv6-prefix;
                     mandatory true;
                     description
                       "An IPv6 destination address as the match.";
                   }
                 }
                 case src-ipv6-address {
                   leaf src-ipv6-prefix {
                     type inet:ipv6-prefix;
                     mandatory true;
                     description
                       "An IPv6 source address as the match.";
                   }
                 }
                 case dest-src-ipv6-address {
                   container dest-src-ipv6-address {
                     description
                       "A combination of an IPv6 source and
                        an IPv6 destination address as the match.";
                     leaf dest-ipv6-prefix {
                       type inet:ipv6-prefix;
                       mandatory true;
                       description
                         "The IPv6 destination address of the match";
                     }
                     leaf src-ipv6-prefix {
                       type inet:ipv6-prefix;
                       mandatory true;
                       description
                         "The IPv6 source address of the match.";
                     }
                   }
                 }
               }
             }
           }
           case mpls-route {
             description
               "MPLS route case.";
             leaf mpls-label {
               type uint32 ;
               mandatory true;
               description
                 "The label used for matching.";
             }
           }
           case mac-route {
             description
               "MAC rib route case.";
             leaf mac-address {
               type uint32 ;
               mandatory true;
               description
                 "The MAC address used for matching.";
             }
           }
           case interface-route {
             description
               "Interface route case.";
             leaf interface-identifier {
               type if:interface-ref;
               mandatory true;
               description
                 "The interface used for matching.";
             }

           }
         }
       }
     }

     grouping route {
       description
         "The common attributes usesd used for all types of route.";
       uses route-prefix;
       container nexthop {
         description
           "The nexthop of the route.";
         uses nexthop;
       }
       container route-statistic {
         description
           "The statistic information of the route.";
         leaf route-state {
           type route-state-def;
           config false;
           description
             "Indicate a route's state: Active or Inactive.";
         }
         leaf route-installed-state {
           type route-installed-state-def;
           config false;
           description
             "Indicate that a route's installed states:
              Installed or uninstalled.";
         }
         leaf route-reason {
           type route-reason-def;
           config false;
           description
             "Indicate the route reason.";
         }
       }
       container route-attributes {
         description
           "Route attributes.";
         uses route-attributes;
       }
       container route-vendor-attributes {
         description
           "Route vendor attributes.";
         uses route-vendor-attributes;
       }
     }
     grouping nexthop-list {
       description
         "A generic nexthop list.";
       list nexthop-list {
         key "nexthop-member-id";
         description
           "A list of nexthop.";
         leaf nexthop-member-id {
           type uint32;
           mandatory true;
           description
             "A nexthop identifier that points
              to a nexthop list member.
              A nexthop list member is a nexthop.";
         }
       }
     }

     grouping nexthop-list-p {
       description
         "A nexthop list with preference parameter.";
       list nexthop-list {
         key "nexthop-member-id";
         description
           "A list of nexthop.";
         leaf nexthop-member-id {
           type uint32;
           mandatory true;
           description
             "A nexthop identifier that points
              to a nexthop list member.
              A nexthop list member is a nexthop.";
         }
         leaf nexthop-preference {
           type nexthop-preference-def;
           mandatory true;
           description
             "Nexthop-preference is used for protection schemes.
              It is an integer value between 1 and 99.  A lower
              value indicates higher preference.  To download a
              primary/standby/tertiary group to the FIB, the
              nexthops that are resolved and have two highest
              preferences are selected.";
         }
       }
     }

     grouping nexthop-list-w {
       description
         "A nexthop list with weight parameter.";
       list nexthop-list {
         key "nexthop-member-id";
         description
           "A list of nexthop.";
         leaf nexthop-member-id {
           type uint32;
           mandatory true;
           description
             "A nexthop identifier that points
              to a nexthop list member.
              A nexthop list member is a nexthop.";
         }
         leaf nexthop-lb-weight {
           type nexthop-lb-weight-def;
           mandatory true;
           description
             "The weight of a nexthop of
              the load balance nexthops.";
         }
       }
     }

     grouping nexthop {
       description
         "The nexthop structure.";
       leaf nexthop-id {
         type uint32;
         mandatory true;
         description
           "The nexthop
           "An identifier of that refers to a nexthop.";
       }
       leaf sharing-flag {
         type boolean;
         mandatory true;
         description
           "To indicate whether a nexthop is sharable
            or non-sharable.
            true - sharable, means the nexthop can be shared
                   with other routes
            false - non-sharable, means the nexthop can not
                   be shared with other routes.";
       }
       choice nexthop-type {
         description
           "Nexthop type options.";
         case nexthop-base {
           container nexthop-base {
             description
               "The base nexthop.";
             uses nexthop-base;
           }
         }
         case nexthop-chain {
           if-feature nexthop-chain;
           container nexthop-chain {
             description
               "A chain nexthop.";
             uses nexthop-list;
           }
         }
         case nexthop-replicates {
           if-feature nexthop-replicates;
           container nexthop-replicates {
             description
               "A replicates nexthop.";
             uses nexthop-list;
           }
         }
         case nexthop-protection {
           if-feature nexthop-protection;
           container nexthop-protection {
             description
               "A protection nexthop.";
             uses nexthop-list-p;
           }
         }
         case nexthop-load-balance {
           if-feature nexthop-load-balance;
           container nexthop-lbs {
             description
               "A load balance nexthop.";
             uses nexthop-list-w;
           }
         }
       }
     }

     grouping nexthop-base {
       description
         "The base nexthop.";
       choice nexthop-base-type {
         description
           "Nexthop base type options.";
         case special-nexthop {
           leaf special {
             type special-nexthop-def;
             description
               "A special nexthop.";
           }
         }
         case egress-interface-nexthop {
            leaf outgoing-interface {
              type if:interface-ref;
              mandatory true;
              description
                "The nexthop is an outgoing interface.";
            }
         }
         case ipv4-address-nexthop {
           leaf ipv4-address {
             type inet:ipv4-address;
             mandatory true;
             description
               "The nexthop is an IPv4 address.";
           }
         }
         case ipv6-address-nexthop {
           leaf ipv6-address {
             type inet:ipv6-address;
             mandatory true;
             description
               "The nexthop is an IPv6 address.";
           }
         }
         case egress-interface-ipv4-nexthop {
           container egress-interface-ipv4-address{
             leaf outgoing-interface {
               type if:interface-ref;
               mandatory true;
               description
                 "Name of the outgoing interface.";
             }
             leaf ipv4-address {
               type inet:ipv4-address;
               mandatory true;
               description
                 "The nexthop points to an interface with
                  an IPv4 address.";
             }
             description
               "The nexthop is an Egress-interface and an ip
                address.This can be usesd used in cases e.g.where
                the ip address is a link-local address.";
           }

         }
         case egress-interface-ipv6-nexthop {
           container egress-interface-ipv6-address {
             leaf outgoing-interface {
               type if:interface-ref;
               mandatory true;
               description
                 "Name of the outgoing interface.";
             }
             leaf ipv6-address {
               type inet:ipv6-address;
               mandatory true;
               description
                 "The nexthop points to an interface with
                  an IPv6 address.";
             }
             description
               "The nexthop is an Egress-interface and an ip
                address.This can be usesd used in cases e.g.where
                the ip address is a link-local address.";
           }
         }
         case egress-interface-mac-nexthop {
           container egress-interface-mac-address {
             leaf outgoing-interface {
               type if:interface-ref;
               mandatory true;
               description
                 "Name of the outgoing interface.";
             }
             leaf ieee-mac-address {
               type uint32;
               mandatory true;
               description
                 "The nexthop points to an interface with
                  a specific mac-address.";
             }
             description
               "The egress interface must be an ethernet
                interface. Address resolution is not required
                for this nexthop.";
           }
         }
         case tunnel-encap-nexthop {
           if-feature nexthop-tunnel;
           container tunnel-encap {
             uses tunnel-encap;
             description
               "This can be an encap representing an IP tunnel or
                MPLS tunnel or others as defined in info model.
                An optional egress interface can be chained to the
                tunnel encap to indicate which interface to send
                the packet out on.  The egress interface is useful
                when the network device contains Ethernet interfaces
                and one needs to perform address resolution for the
                IP packet.";
           }
         }
         case tunnel-decap-nexthp tunnel-decap-nexthop {
           if-feature nexthop-tunnel;
           container tunnel-decap {
             uses tunnel-decap;
             description
               "This is to specify decapsulating a tunnel header.";
           }
         }
         case logical-tunnel-nexthop {
           if-feature nexthop-tunnel;
           container logical-tunnel {
             uses logical-tunnel;
             description
               "This can be a MPLS LSP or a GRE tunnel (or others
                as defined in This document), that is represented
                by a unique identifier (e.g. name).";
           }
         }
         case rib-name-nexthop {
           leaf rib-name {
             type string;
             description
               "A nexthop pointing to a rib indicates that the
                route lookup needs to continue in The specified
                rib. This is a way to perform chained lookups.";
           }
         }
         case nexthop-identifier {
           leaf nexthop-ref {
             type nexthop-ref;
             mandatory true;
             description
               "A nexthop reference that points to a nexthop.";
           }
         }
       }
     }
     grouping route-vendor-attributes {
       description
         "Route vendor attributes.";
     }

     grouping logical-tunnel {
       description
         "A logical tunnel that is identified
          by a type and a tunnel name.";
       leaf tunnel-type {
         type tunnel-type-def;
         mandatory true;
         description
           "A tunnel type.";
       }
       leaf tunnel-name {
         type string;
         mandatory true;
         description
           "A tunnel name that points to a logical tunnel.";
       }
     }

     grouping ipv4-header {
       description
         "The IPv4 header encapsulation information.";
       leaf src-ipv4-address {
         type inet:ipv4-address;
         mandatory true;
         description
           "The source ip address of the header.";
       }
       leaf dest-ipv4-address {
         type inet:ipv4-address;
         mandatory true;
         description
           "The destination ip address of the header.";
       }
       leaf protocol {
         type uint8;
         mandatory true;
         description
           "The protocol id of the header.";
       }
       leaf ttl {
         type uint8;
         description
           "The TTL of the header.";

       }
       leaf dscp {
         type uint8;
         description
           "The DSCP field of the header.";
       }
     }

     grouping ipv6-header {
       description
         "The IPv6 header encapsulation information.";
       leaf src-ipv6-address {
         type inet:ipv6-address;
         mandatory true;
         description
           "The source ip address of the header.";
       }
       leaf dest-ipv6-address {
         type inet:ipv6-address;
         mandatory true;
         description
           "The destination ip address of the header.";
       }
       leaf next-header {
         type uint8;
         mandatory true;
         description
           "The next header of the IPv6 header.";
       }
       leaf traffic-class {
         type uint8;
         description
           "The traffic class value of the header.";
       }
       leaf flow-label {
         type uint16;
         description
           "The flow label of the header.";
       }
       leaf hop-limit {
         type uint8;
         description
           "The hop limit the header.";
       }
     }

     grouping nvgre-header {
       description
         "The NvGRE header encapsulation information.";
       choice nvgre-type {
         description
           "NvGRE can use eigher IPv4
            or IPv6 header for encapsulation.";
         case ipv4 {
           uses ipv4-header;
         }
         case ipv6 {
           uses ipv6-header;
         }
       }
       leaf virtual-subnet-id {
         type uint32;
         mandatory true;
         description
           "The subnet identifier of the NvGRE header.";
       }
       leaf flow-id {
         type uint16;
         description
           "The flow identifier of the NvGRE header.";
       }
     }

     grouping vxlan-header {
       description
         "The VxLAN encapsulation header information.";
       choice vxlan-type {
         description
           "NvGRE can use eigher IPv4
            or IPv6 header for encapsulation.";
         case ipv4 {
           uses ipv4-header;
         }
         case ipv6 {
           uses ipv6-header;
         }
       }
       leaf vxlan-identifier {
         type uint32;
         mandatory true;
         description
           "The VxLAN identifier of the VxLAN header.";
       }
     }

     grouping gre-header {
       description
         "The GRE encapsulation header information.";
       choice dest-address-type {
         description
           "GRE options: IPv4 and IPv6";
         case ipv4 {
           leaf ipv4-dest {
             type inet:ipv4-address;
             mandatory true;
             description
               "The destination ip address of the GRE header.";
           }
         }
         case ipv6 {
           leaf ipv6-dest {
             type inet:ipv6-address;
             mandatory true;
             description
               "The destination ip address of the GRE header.";
           }
         }
       }
       leaf protocol-type {
         type uint16;
         mandatory true;
         description
           "The protocol type of the GRE header.";
       }
       leaf key {
         type uint64;
         description
           "The GRE key of the GRE header.";
       }
     }

     grouping mpls-header {
       description
         "The MPLS encapsulation header information.";
       list label-operations {
         key "label-oper-id";
         description
           "Label operations.";
         leaf label-oper-id {
           type uint32;
           description
             "An optional identifier that points
              to a label operation.";
         }
         choice label-actions {
           description
             "Label action options.";
           case label-push {
             container label-push {
               description
                 "Label push operation.";
               leaf label {
                 type uint32;
                 mandatory true;
                 description
                   "The label to be pushed.";
               }
               leaf s-bit {
                 type boolean;
                 description
                   "The s-bit of the label to be pushed. ";
               }
               leaf tc-value {
                 type uint8;
                 description
                   "The traffic class value of the label to be pushed.";
               }
               leaf ttl-value {
                 type uint8;
                 description
                   "The TTL value of the label to to be pushed.";
               }
             }
           }
           case label-swap {
             container label-swap {
               description
                 "Label swap operation.";
               leaf in-label {
                 type uint32;
                 mandatory true;
                 description
                   "The label to be swapped.";
               }
               leaf out-label {
                 type uint32;
                 mandatory true;
                 description
                   "The out MPLS label.";
               }
               leaf ttl-action {
                 type ttl-action-def;
                 description
                   "The label ttl actions:
                    - No-action, or
                    - Copy to inner label,or
                    - Decrease (the in label) by 1 and
                      copy to the out label.";
               }
             }
           }
         }
       }
     }

     grouping tunnel-encap{
       description
         "Tunnel encapsulation inforamtion.";
       choice tunnel-type {
         description
           "Tunnel options for next-hops.";
         case ipv4 {
           if-feature ipv4-tunnel;
           container ipv4-header {
             uses ipv4-header;
             description
               "IPv4 header.";
           }
         }
         case ipv6 {
           if-feature ipv6-tunnel;
           container ipv6-header {
             uses ipv6-header;
             description
               "IPv6 header.";
           }
         }
         case mpls {
           if-feature mpls-tunnel;
           uses mpls-header;
           container mpls-header {
             uses mpls-header;
             description
               "MPLS header.";
           }
         }
         case gre {
           if-feature gre-tunnel;
           container gre-header {
             uses gre-header;
             description
               "GRE header.";
           }
         }
         case nvgre {
           if-feature nvgre-tunnel;
           container nvgre-header {
             uses nvgre-header;
             description
               "NvGRE header.";
           }
         }
         case vxlan {
           if-feature vxlan-tunnel;
           container vxlan-header {
             uses vxlan-header;
             description
               "VxLAN header.";
           }
         }
       }
     }

     grouping tunnel-decap {
       description
         "Tunnel decapsulation inforamtion.";
       choice tunnel-type {
         description
           "Nexthop tunnel type options.";
         case ipv4 {
           if-feature ipv4-tunnel;
           container ipv4-decap {
             description
               "IPv4 decap.";
             leaf ipv4-decap  {
               type tunnel-decap-action-def;
               mandatory true;
               description
                 "IPv4 decap operations.";
             }
             leaf ttl-action {
               type ttl-action-def;
               description
                 "The ttl actions:
                  no-action or copy to inner header.";
             }
           }
         }
         case ipv6 {
           if-feature ipv6-tunnel;
           container ipv6-decap {
             description
               "IPv6 decap.";
             leaf ipv6-decap {
               type tunnel-decap-action-def;
               mandatory true;
               description
                 "IPv6 decap operations.";
             }
             leaf hop-limit-action {
               type hop-limit-action-def;
               description
                 "The hop limit actions:
                  no-action or copy to inner header.";
             }
           }
         }
         case mpls {
           if-feature mpls-tunnel;
           container label-pop {
             description
               "MPLS decap.";
             leaf label-pop {
               type mpls-label-action-def;
               mandatory true;
               description
                 "Pop a label from the label stack.";
             }
             leaf ttl-action {
               type ttl-action-def;
               description
                 "The label ttl actions:
                  no-action or copy to inner label";
             }
           }
         }
       }
     }

     grouping route-attributes {
       description
         "Route attributes.";
       leaf route-preference {
         type uint32;
         mandatory true;
         description
           "ROUTE_PREFERENCE: This is a numerical value that
            allows for comparing routes from different
            protocols.  Static configuration is also
            considered a protocol for the purpose of this
            field.  It iss also known as administrative-distance.
            The lower the value, the higher the preference.";
       }
       leaf local-only {
         type boolean ;
         mandatory true;
         description
           "Indicate whether the attributes is local only.";
       }
       container address-family-route-attributes{
         description
           "Address family related route attributes.";
         choice route-type {
           description
             "Address family related route attributes.";
           case ip-route-attributes {
           }
           case mpls-route-attributes {
           }
           case ethernet-route-attributes {
           }
         }
       }
     }

     container routing-instance {
       description
         "A routing instance, in the context of
          the RIB information model, is a collection
          of RIBs, interfaces, and routing parameters";
       leaf name {
         type string;
         mandatory true;
         description
           "The name of the routing instance.This MUST
            be unique across all routing instances in
            a given network device.";
       }
       list interface-list {
         key "name";
         description
           "This represents the list of interfaces associated
            with this routing instance. The interface list helps
            constrain the boundaries of packet forwarding.
            Packets coming on these interfaces are directly
            associated with the given routing instance. The
            interface list contains a list of identifiers, with
            each identifier uniquely identifying an interface.";
         leaf name {
           type if:interface-ref;
           description
             "A reference to the name of a network layer interface.";
         }
       }
       leaf router-id {
         type yang:dotted-quad;
         description
           "Router ID - 32-bit number in the form of a dotted quad.";
       }
       leaf lookup-limit {
         type uint8;
         description
           "A limit on how many levels of a lookup can be performed.";
       }
       list rib-list {
         key "name";
         description
           "A list of RIBs that are associated with the routing
            instance.";
         leaf name {
           type string;
           mandatory true;
           description
             "A reference to the name of each rib.";
         }
         leaf rib-family {
           type rib-family-def;
           mandatory true;
           description
             "The address family of a rib.";
         }
         leaf ip-rpf-check {
           type boolean;
           description
             "Each RIB can be optionally associated with a
              ENABLE_IP_RPF_CHECK attribute that enables Reverse
              path forwarding (RPF) checks on all IP routes in that
              RIB.  Reverse path forwarding (RPF) check is used to
              prevent spoofing and limit malicious traffic.";
         }
         list route-list {
           key "route-index";
           description
             "A list of routes of a rib.";
           uses route;
         }
       }
     }

     /*RPC Operations*/
     rpc rib-add {
       description
         "To add a rib to a instance";
       input {
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of the rib
              that is to be added.";
         }
         leaf rib-family {
           type rib-family-def;
           mandatory true;
           description
             "The address family of the rib.";
         }
         leaf ip-rpf-check {
           type boolean;
           description
             "Each RIB can be optionally associated with a
              ENABLE_IP_RPF_CHECK attribute that enables Reverse
              path forwarding (RPF) checks on all IP routes in that
              RIB.  Reverse path forwarding (RPF) check is used to
              prevent spoofing and limit malicious traffic.";
         }
       }
       output {
         leaf result {
           type boolean;
           mandatory true;
           description
             "Return the result of the rib-add operation.
              true  - success;
              false - failed."; failed";
         }
         leaf reason {
           type string;
           description
             "The specific reason that causes the failure.";
         }

       }
     }

     rpc rib-delete {
       description
         "To delete a rib from a routing instance.
          After deleting the rib, all routes installed
          in the rib will be deleted as well.";
       input {
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of the rib
              that is to be deleted.";
         }
       }
       output {
         leaf result {
           type boolean;
           mandatory true;
           description
             "Return the result of the rib-delete operation.
              true  - success;
              false - failed."; failed";
         }
         leaf reason {
           type string;
           description
             "The specific reason that causes failure.";
         }
       }
     }

     grouping route-operation-state {
       description
         "Route operation state.";
       leaf success-count {
         type uint32;
         mandatory true;
         description
           "The numbers of routes that are successfully
            added/deleted/updated.";
       }
       leaf failed-count {
         type uint32;
         mandatory true;
         description
           "The numbers of the routes that are failed
            to be added/deleted/updated.";
       }
       container failure-detail {
         description
           "The failure detail reflects the reason why a route
            operation fails. It is a array that includes the route
            index and error code of the failed route.";
         list failed-routes {
            key "route-index";
            description
             "The list of failed routes.";
            leaf route-index {
             type uint32;
             description
               "The route index of the failed route.";
           }
           leaf error-code {
             type uint32;
             description
               "The error code that reflects the failure reason.";
           }
         }
       }
     }

     rpc route-add {
       description
         "To add a route or a list of route to a rib";
       input {
         leaf return-failure-detail {
           type boolean;
           default false;
           description
             "Whether return the failure detail.
              true  - return the failure detail;
              false - do not return the failure detail;
              the default is false.";
         }
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
         container routes {
           description
             "The routes to be added to the rib.";

           list route-list {
             key "route-index";
             description
               "The list of routes to be added.";
             uses route-prefix;
             container route-attributes {
               uses route-attributes;
               description
                 "Route
                 "The route attributes.";
             }
             container route-vendor-attributes {
               if-feature route-vendor-attributes;
               uses route-vendor-attributes;
               description
                 "Route
                 "The route vendor attributes.";
             }
             container nexthop {
               uses nexthop;
               description
                 "Nexthop.";
                 "The nexthop of the added route.";
             }
           }
         }
       }
       output {
         leaf result {
           type boolean;
           mandatory true;
           description
             "Return the result of the route-add operation.
              true - success;
              false - failed.";
         }
         uses route-operation-state;
       }
     }

     rpc route-delete {
       description
         "To delete a route or a list of route from a rib";
       input {
         leaf return-failure-detail {
           type boolean;
           default false;
           description
             "Whether return the failure detail.
              true  - return the failure detail;
              false - do not return the failure detail;
              the default is false.";
         }
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
         container routes {
           description
             "The routes to be added to the rib.";
           list route-list{
             key "route-index";
             description
               "The list of routes to be deleted.";
             uses route-prefix;
           }
         }
       }
       output {
         leaf result
         uses route-operation-state;
       }
     }

     grouping route-update-options {
           type boolean ;
           mandatory true;
       description
             "Return
         "Update options:
          1. update the result of nexthop
          2. update the route-delete operation.
              true - success;
              false - failed."; route attributes
          3. update the route-vendor-attributes.";
       choice update-options {
         description
           "Update options:
            1. update the nexthop
            2. update the route attributes
            3. update the route-vendor-attributes.";
         case update-nexthop {
           container updated-nexthop {
             uses nexthop;
             description
               "The nexthop used for updating.";
           }
         }
         case update-route-attributes {
           container updated-route-attr {
             uses route-attributes;
             description
               "The route attributes used for updating.";
           }
         }
         case update-route-vendor-attributes {
           container updated-route-vendor-attr {
             uses route-vendor-attributes;
             description
               "The vender route attributes used for updating.";
           }

         }
       }
     }

     rpc route-update {
       description
         "To update a route or a list of route of a rib.
          The inputs:
            1. The match conditions, could be:
              a. route prefix, or
              b. route attribtes, attributes, or
              c. nexthop;
            2. The update parameters to be used:
              a. new nexhop; nexthop;
              b. new route attributes; attributes;nexthop
          Actions:
            1. update the nexthop
            2. update the route attributes
          The outputs:
            true
            success-count - success;
            false the number of routes updated;
            failed-count - failed. the number of routes fail to update
            failure-detail - the detail failure info.
          ";
       input {
         leaf return-failure-detail {
           type boolean;
           default false;
           description
             "Whether return the failure detail.
              true  - return the failure detail;
              false - do not return the failure detail;
              the default is false.";
         }
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
         choice match-conditions match-options {
           description
             "Match options.";
           case match-route-prefix {
             description
               "Update the routes that match route
                prefix(es) condition.";
             container input-routes {
               description
                 "The matched routes to be updated.";
               list route-list {
                 key "route-index";
                 description
                   "The list of routes to be updated.";
                 uses route-prefix;
                 choice update-actions-prefix {
                   description
                     "Update actions:
                      1. update the nexthop
                      2. update the route attributes
                      3. update the route-vendor-attributes.
                      ";
                   case update-nexthop {
                     uses nexthop;
                   }
                   case update-route-attributes {
                     uses route-attributes;
                   }
                   case update-route-vendor-attributes {
                     if-feature route-vendor-attributes;
                 uses route-vendor-attributes;
                   }
                 } route-update-options;
               }
             }
           }
           case match-route-attributes {
             description
               "Update the routes that match the
                route attributes condition.";
             container input-route-attributes {
               description
                 "The route attributes are used for matching.";
               uses route-attributes;
             }
             choice update-actions-attributes
             container update-parametors {
               description
                 "Update actions: options:
                  1. update the nexthop
                  2. update the route attributes
                  3. update the route-vendor-attributes.";
               case update-nexthop {
               uses nexthop;
               }
               case update-route-attributes {
                 uses route-attributes;
               }
               case update-route-vendor-attributes {
                 if-feature route-vendor-attributes;
                 uses route-vendor-attributes;
               } route-update-options;
             }
           }
           case match-route-vendor-attributes {
             if-feature route-vendor-attributes;
             description
               "Update the routes that match the
                vendor attributes condition";
             container input-route-vendor-attributes {
               description
                 "The vendor route attributes are used for matching.";
               uses route-vendor-attributes;
             }
             choice update-actions-vendor-attributes
             container update-parameters-vendor {
               description
                 "Update actions: options:
                  1. update the nexthop
                  2. update the route attributes
                  3. update the route-vendor-attributes.";
               case update-nexthop {
                 uses nexthop;
               }
               case update-route-attributes {
                 uses route-attributes;
               }
               case update-route-vendor-attributes {
               uses route-vendor-attributes;
               } route-update-options;
             }
           }
           case match-nexthop {
             description
               "Update the routes that match the nexthop.";
             container input-nexthop {
               description
                 "The nexthop used for matching.";
               uses nexthop;
             }

             choice update-actions-nexthop
             container update-parameters-nexthop {
               description
                 "Update actions: options:
                  1. update the nexthop
                  2. update the route attributes
                  3. update the route-vendor-attributes.";
               case update-nexthop {
                 uses nexthop;
               }
               case update-route-attributes {
                 uses route-attributes;
               }
               case update-route-vendor-attributes {
                 if-feature route-vendor-attributes;
               uses route-vendor-attributes;
               } route-update-options;
             }
           }
         }
       }
       output {
         leaf result {
           type boolean ;
           mandatory true;
           description
             "Return the result of the route-update operation.
              true - success;
              false - failed.";
         }
         uses route-operation-state;
       }
     }

     rpc nh-add {
       description
         "To add a nexthop to a rib.
          Inputs parameters:
            1. rib name
            2. nexthop;
          Actions:
            Add the nexthop to the rib
          Outputs:
            1.Operation result:
              true  - success
              false - failed;
            2. nexthop identifier.";
       input {
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
         uses nexthop;
       }
       output {
         leaf result {
           type boolean ; boolean;
           mandatory true;
           description
             "Return the result of the nh-add rib-add operation.
              true  - success;
              false - failed."; failed;";
         }
         leaf reason {
           type string;
           description
             "The specific reason that causes the failure.";
         }
         leaf nexthop-id {
           type uint32;
           mandatory true;
           description
             "A nexthop identifer that is allocated to the nexthop.";
         }
       }
     }

     rpc nh-delete {
       description
         "To delete a nexthop from a rib";
       input {
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
         uses nexthop;
       }
       output {
         leaf result {
           type boolean ; boolean;
           mandatory true;
           description
             "Return the result of the nh-delete rib-add operation.
              true  - success;
              false - failed.";
         }
         leaf reason {
           type string;
           description
             "The specific reason that causes the failure.";
         }
       }
     }
     /*Notifications*/
     notification nexthop-resolution-status-change {
       description
         "Nexthop resolution status (resolved/unresolved)
          notification.";
       container nexthop{
         description
           "The nexthop.";
         uses nexthop;
       }
       leaf nexthop-state {
         type nexthop-state-def;
         mandatory true;
         description
           "Nexthop resolution status (resolved/unresolved)
            notification.";
       }
     }

     notification route-change {
       description
         "Route change notification.";
       leaf rib-name {
         type string;
         mandatory true;
         description
           "A reference to the name of a rib.";
       }
       leaf rib-family {
         type rib-family-def;
         mandatory true;
         description
           "A reference to address family of a rib.";
       }
       uses route-prefix;
       leaf route-installed-state {
         type route-installed-state-def;
         mandatory true;
         description
           "Indicates whether the route got installed in the FIB.";
       }
       leaf route-state {
         type route-state-def;
         mandatory true;
         description
           "Indicates whether a route is fully resolved and
            is a candidate for selection.";
       }
       leaf route-change-reason {
         type route-reason-def;
         mandatory true;
         description
           "Return the reason that causes the route change.";
       }
     }
   }

   //<CODE

   <CODE ENDS>

4.  IANA Considerations

   This document requests to register a URI in the "IETF XML registry"
   [RFC3688]:

    --------------------------------------------------------------------
    URI: urn:ietf:params:xml:ns:yang:ietf-i2rs-rib
    Registrant Contact: The IESG.XML:
    N/A, the requested URI is an XML namespace.
    --------------------------------------------------------------------

   This document requests to register a YANG module in the "YANG Module
   Names registry" [RFC6020]:

    --------------------------------------------------------------------
    name:         ietf-i2rs-rib
    namespace:    urn:ietf:params:xml:ns:yang:ietf-i2rs-rib
    prefix:       iir
    reference:    RFC XXXX
    --------------------------------------------------------------------

5.  Security Considerations

   This document introduces no extra new security threat and SHOULD
   follow the security requirements as stated in
   [I-D.ietf-i2rs-architecture].

6.  Contributors

   The following individuals also contribute to this document.

   o  Zekun He, Tencent Holdings Ltd

   o  Sujian Lu, Tencent Holdings Ltd

   o  Jeffery Zhang, Juniper Networks

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

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

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

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <http://www.rfc-editor.org/info/rfc6991>.

7.2.  Informative References

   [I-D.ietf-i2rs-architecture]
              Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
              Nadeau, "An Architecture for the Interface to the Routing
              System", draft-ietf-i2rs-architecture-09 (work in
              progress), March 2015.

   [I-D.ietf-i2rs-rib-info-model]
              Bahadur, N., Kini, S., and J. Medved, "Routing Information
              Base Info Model", draft-ietf-i2rs-rib-info-model-08 (work
              in progress), October 2015.

   [I-D.ietf-i2rs-usecase-reqs-summary]
              Hares, S. and M. Chen, "Summary of I2RS Use Case
              Requirements", draft-ietf-i2rs-usecase-reqs-summary-01
              (work in progress), May 2015.

Authors' Addresses

   Lixing Wang
   Individual

   Email: wang_little_star@sina.com
   Hariharan Ananthakrishnan
   Packet Design

   Email: hari@packetdesign.com

   Mach(Guoyi) Chen
   Huawei

   Email: mach.chen@huawei.com

   Amit Dass
   Ericsson
   Torshamnsgatan 48.
   Stockholm  16480
   Sweden

   Email: amit.dass@ericsson.com

   Sriganesh Kini
   Ericsson

   Email: sriganesh.kini@ericsson.com

   Nitin Bahadur
   Bracket Computing

   Email: nitin_bahadur@yahoo.com