Network Working Group                                            L. Wang
Internet-Draft                                                    Huawei                                                Individual
Intended status: Standards Track                      H. Ananthakrishnan
Expires: April 1, 20, 2016                                    Packet Design
                                                                 M. Chen
                                                                  Huawei
                                                                 A. Dass
                                                                 S. Kini
                                                                Ericsson
                                                              N. Bahadur
                                                       Bracket Computing
                                                      September 29,
                                                        October 18, 2015

          A YANG Data Model for Routing Information Base (RIB)
                   draft-ietf-i2rs-rib-data-model-01
                   draft-ietf-i2rs-rib-data-model-02

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 April 1, 20, 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  . . . . . . . . . . . . . . . . . . . . .   5   7
     2.2.  Routing Instance and Rib  . . . . . . . . . . . . . . . .   6   7
     2.3.  Route . . . . . . . . . . . . . . . . . . . . . . . . . .   7   8
     2.4.  Nexthop . . . . . . . . . . . . . . . . . . . . . . . . .   8   9
     2.5.  RPC Operations  . . . . . . . . . . . . . . . . . . . . .  14
     2.6.  Notifications . . . . . . . . . . . . . . . . . . . . . .  12  16
   3.  YANG Modules  . . . . . . . . . . . . . . . . . . . . . . . .  14  18
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  37  58
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  37  58
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  58
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  37
     6.1.  59
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  37
     6.2.  59
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  37  59
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  38  59

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 RIB information model is defined in
   [I-D.ietf-i2rs-rib-info-model].

   This document defines a YANG [RFC6020][RFC6021] [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 module.  To give a whole view of the structure tree, some details
   of the tree are omitted.  The detail are introduced in the following
   sub-sections.

   module: i2rs-rib
      +--rw nexthop-capacity
         |  ...
         +--rw nexthop-tunnel-encap-capacity
         |  ...
         +--rw routing-instance
         +--rw instance-name name              string
         +--rw interface-list* [name]
         |  +--rw name if:interface-ref
         +--rw router-id?        yang:dotted-quad
         +--rw lookup-limit?     uint8
         +--rw rib-list* [rib-name] [name]
            +--rw rib-name name                   string
            +--rw rib-family             rib-family-def
            +--rw enable-ip-rpf-check?   boolean
            +--rw route-list* [route-index]
               +--rw route-index                uint64
               +--rw route-type                 route-type-def
               +--rw match
               |  +--rw (rib-route-type)?
               |     +--:(ipv4)
               |     |  ...
               |     +--:(ipv6)
               |     |  ...
               |     +--:(mpls-route)
               |     |  ...
               |     +--:(mac-route)
               |     |  ...
               |     +--:(interface-route)
               |        ...
               +--rw nexthop
               |  +--rw nexthop-id            uint32
               |  +--rw sharing-flag          boolean
               |  +--rw (nexthop-type)?
               |     +--:(nexthop-base)
               |     |  ...
               |     +--:(nexthop-chain) {nexthop-chain}?
               |     |  ...
               |     +--:(nexthop-protection) {nexthop-protection}?
               |     |  ...
               |     +--:(nexthop-load-balance) {nexthop-load-balance}?
               |     |  ...
               |     +--:(nexthop-replicate)     +--:(nexthop-replicates) {nexthop-replicates}?
               |        ...
               +--rw route-statistic
               |  ...
               +--rw route-attributes
               |  ...
               +--rw route-preference           uint32 route-vendor-attributes
   rpcs:
      +---x rib-add
      |  +--rw local-only  +--ro input
      |  |  +--ro rib-name               string
      |  |  +--ro rib-family             rib-family-def
      |  |  +--ro enable-ip-rpf-check?   boolean
      |  +--rw address-family-route-attributes  +--ro output
      |     +--rw (route-type)?     +--ro result boolean
      +---x rib-delete
      |        +--:(ip-route-attributes)  +--ro input
      |        +--:(mpls-route-attributes)  |        +--:(eThernet-route-attributes)
                  +--rw route-vendor-attributes
      notifications:
         +---n nexthop-resolution-status-change  +--ro rib-name string
      |  +--ro nexthop output
      |     +--ro result boolean
      +---x route-add
      |  +--ro nexthop-id           uint32 input
      |  |  +--ro (nexthop-type)? rib-name string
      |  |     +--:(nexthop-base)  +--ro routes
      |  |     +--ro route-list* [route-index]
      |  |        ...
      |  +--ro output
      |     +--ro result boolean
      +---x route-delete
      |  +--ro input
      |  |  +--ro rib-name string
      |  |  +--ro routes
      |     +--:(nexthop-protection)  |     +--ro route-list* [route-index]
      |  |        ...
      |  +--ro output
      |     +--ro result boolean
      +---x route-update
      |  +--ro input
      |  |  +--ro rib-name                           string
      |  |  +--ro (match-conditions)?
      |     +--:(nexthop-load-balance)  |     +--:(match-route-prefix)
      |  |     |  ...
      |  |     +--:(match-route-attributes)
      |  |     |  ...
      |  |     +--:(nexthop-replicate)     +--:(match-nexthop)
      |  |        ...
      |  +--ro nexthop-state        nexthop-state-def
         +---n route-change output
      |     +--ro instance-name            string result boolean
      +---x nh-add
      |  +--ro input
      |  |  +--ro rib-name              string
      |  |  +--ro rib-family               rib-family-def
            +--ro route-index              uint64
            +--ro route-type               route-type-def nexthop-id            uint32
      |  |  +--ro match sharing-flag          boolean
      |  |  +--ro (rib-route-type)? (nexthop-type)?
      |  |     +--:(nexthop-base)
      |     +--:(ipv4)  |     |  ...
      |     +--:(ipv6)  |     +--:(nexthop-chain) {nexthop-chain}?
      |  |     |  ...
      |     +--:(mpls-route)  |     +--:(nexthop-protection) {nexthop-protection}?
      |  +--ro mpls-label              uint32  |     +--:(mac-route)     |  ...
      |  |     +--:(nexthop-load-balance) {nexthop-load-balance}?
      |  |     |  ...
      |  |     +--:(nexthop-replicates) {nexthop-replicates}?
      |  |        ...
      |  +--ro mac-address output
      |     +--ro result        boolean
      |     +--ro nexthop-id uint32
      +---x nh-delete
         +--ro input
         |     +--:(interface-route)  +--ro rib-name              string
         |  +--ro interface-identifier if:interface-ref (nexthop-context-or-id)?
         |     +--:(nexthop-context)
         |     |  ...
         |     +--:(nexthop-identifier)
         |        +--ro route-installed-state route-installed-state-def nexthop-identifer     uint32
         +--ro route-state           route-state-def output
            +--ro route-reason          route-reason-def

                  Figure 1 Overview of I2RS module result boolean
   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-protection) {nexthop-protection}?
      |  |     |  ...
      |  |     +--:(nexthop-load-balance) {nexthop-load-balance}?
      |  |     |  ...
      |  |     +--:(nexthop-replicates) {nexthop-replicates}?
      |  |        ...
      |  +--ro nexthop-state nexthop-state-def
      +---n route-change
         +--ro rib-name                 string
         +--ro rib-family               rib-family-def
         +--ro route-index              uint64
         +--ro route-type               route-type-def
         +--ro match
         |  +--ro (rib-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-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.

   The structure of the next-hop-capacity and the nexthop-tunnel-encap-
   capacity is shown in the following figure:

   Editor Notes: this version only includes

   This module uses the nexthop-hop feature and nexthop-
   tunnel-encap capabilities, there may also need if-feature statements to define RIB
   capabilities in future revision.

      +--rw nexthop-capacity
      |  +--rw support-tunnel?         boolean
      |  +--rw support-chains?         boolean
      |  +--rw support-list-of-list?   boolean
      |  +--rw support-replication?    boolean
      |  +--rw support-weighted?       boolean
      |  +--rw support-protection?     boolean
      |  +--rw lookup-limit?           uint8
      +--rw nexthop-tunnel-encap-capacity
      |  +--rw support-ipv4?    boolean
      |  +--rw support-ipv6?    boolean
      |  +--rw support-mpls?    boolean
      |  +--rw support-gre?     boolean
      |  +--rw support-vxlan?   boolean
      |  +--rw support-nvgre?   boolean

             Figure 2 RIB Capability 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 a
   routing instance, there would be multiple RIBs as well.  Therefore,
   this model uses "list" to express the RIBs.  The structure tree is
   shown as following figure.

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

       Figure 3 2: Routing Instance Stuture

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 rib list.

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

                      Figure 4 Route 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 of all other nexthop types.  The first level of the base
      nexthop 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.

      *  nexthop-id

      *  egress-interface

      *  logical-tunnel

      *  tunnel-encap

   o  Load-balance: Designed for load-balance case. 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            uint32
|  +--rw sharing-flag          boolean
|  +--rw (nexthop-type)?
|     +--:(nexthop-base)
|     |  +--rw nexthop-base  ...(refer to Figure 5)
|     +--:(nexthop-chain) {nexthop-chain}?
|     |  +--rw nexthop-chain* [nexthop-chain-id] nexthop-chain
|     |     +--rw nexthop-chain-id        uint32 nexthop-chain* [nexthop-chain-member-id]
|     |        +--rw (nexthop-chain-type)? nexthop-chain-member-id uint32
|     +--:(nexthop-protection) {nexthop-protection}?
|              ... (refer to Figure 6)     |     +--:(nexthop-protection)  +--rw nexthop-protection
|     |     +--rw nexthop-protection-list* [nexthop-protection-id] [...-member-id]
|     |        +--rw nexthop-protection-id nexthop-protection-member-id uint32
|     |        +--rw nexthop-preference nexthop-preference-def
|     |     +--rw nexthop                  nexthop-ref
      |     +--:(nexthop-load-balance) {nexthop-load-balance}?
|     |  +--rw nexthop-lb
|     |     +--rw nexthop-lbs* [nexthop-lbs-id] [nexthop-lbs-member-id]
|     |        +--rw nexthop-lbs-id nexthop-lbs-member-id uint32
|     |        +--rw nhop-lb-weight           nhop-lb-weight-def
|     +--:(nexthop-replicates) {nexthop-replicates}?
|        +--rw nexthop-lb-member        nexthop-ref
      |     +--:(nexthop-replicate) nexthop-replicates
|           +--rw nexthop-replicate nexthop-replicates* [nexthop-replicates-member-id]
|              +--rw nexthop-replicates* [nexthop-replicates-id]
      |              +--rw nexthop-replicates-id nexthop-replicates-member-id uint32
      |              +--rw nexthop-replicate?        nexthop-ref

                   Figure 5 4: Nexhop Structure

   Figure 6 (as shown blow) is a sub-tree of nexthop, it's under the
   nexthop chain base node.

   +--rw (nexthop-chain-type)?
      +--:(nexthop-chain-member-special)
      |  +--rw nexthop-chain-member-special

 +--:(nexthop-base)
 |  +--rw nexthop-chain-member-special? special-nexthop-def
      +--:(nexthop-chain-member-identifier) nexthop-base
 |     +--rw (nexthop-identifier-type)? (nexthop-base-type)?
 |     +--:(nexthop-chain-name)        +--:(special-nexthop)
 |        |  +--rw nexthop-chain-name         string special?                         special-nexthop-def
 |     +--:(nexthop-chain-id)        +--:(egress-interface-nexthop)
 |        +--rw nexthop-chain-id           uint32
      +--:(egress-interface-next-hop)        |  +--rw outgoing-interface               if:interface-ref
      +--:(ipv4-address-next-hop)
 |        +--:(ipv4-address-nexthop)
 |        |  +--rw next-hop-ipv4-address ipv4-address                     inet:ipv4-address
      +--:(ipv6-address-next-hop)
 |        +--:(ipv6-address-nexthop)
 |        |  +--rw next-hop-ipv6-address ipv6-address                     inet:ipv6-address
      +--:(egress-interface-ipv4-next-hop)
 |        +--:(egress-interface-ipv4-nexthop)
 |        |  +--rw next-hop-egress-interface-ipv4-address egress-interface-ipv4-address
 |        |     +--rw outgoing-interface if:interface-ref
 |        |     +--rw next-hop-egress-ipv4-address ipv4-address          inet:ipv4-address
      +--:(egress-interface-ipv6-next-hop)
 |        +--:(egress-interface-ipv6-nexthop)
 |        |  +--rw next-hop-egress-interface-ipv6-address egress-interface-ipv6-address
 |        |     +--rw outgoing-interface if:interface-ref
 |        |     +--rw next-hop-egress-ipv6-address inet:ipv4-address
      +--:(egress-interface-mac-next-hop) ipv6-address          inet:ipv6-address
 |        +--:(egress-interface-mac-nexthop)
 |        |  +--rw next-hop-egress-interface-mac-address egress-interface-mac-address
 |        |     +--rw outgoing-interface if:interface-ref
 |        |     +--rw ieee-mac-address      uint32
      +--:(tunnel-encap-next-hop)
 |        +--:(tunnel-encap-nexthop) {nexthop-tunnel}?
 |        |  +--rw tunnel-encap
 |        |     +--rw (tunnel-type)?
 |        |        +--:(ipv4) {ipv4-tunnel}?
 |        |        |  +--rw source-ipv4-address inet:ipv4-address
 |        |        |  +--rw destination-ipv4-address inet:ipv4-address
 |        |        |  +--rw protocol                    uint8
 |        |        |  +--rw ttl?                        uint8
 |        |        |  +--rw dscp?                       uint8
 |        |        +--:(ipv6) {ipv6-tunnel}?
 |        |        |  +--rw source-ipv6-address inet:ipv6-address
 |        |        |  +--rw destination-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-action-type)?
 |        |        |     +--:(mpls-push)
 |        |        |     |  +--rw mpls-push                   boolean
 |        |        |     |  +--rw mpls-label                  uint32
 |        |        |     |  +--rw s-bit?                      boolean
 |        |        |     |  +--rw tos-value? tc-value?                   uint8
 |        |        |     |  +--rw ttl-value?                  uint8
 |        |        |     +--:(mpls-pop)     +--:(mpls-swap)
 |        |        |        +--rw mpls-pop mpls-swap                   boolean
 |        |        |        +--rw mpls-in-label               uint32
 |        |        |        +--rw mpls-out-label              uint32
 |        |        |        +--rw ttl-action?        uint8 ttl-action-def
 |        |        +--:(gre) {gre-tunnel}?
 |        |        |  +--rw gre-ip-destination inet:ipv4-address
 |        |        |  +--rw gre-protocol-type inet:ipv4-address
 |        |        |  +--rw gre-key?                 uint64
 |        |        +--:(nvgre) {nvgre-tunnel}?
 |        |        |  +--rw (nvgre-type)?
 |        |        |  |  +--:(ipv4)
 |        |        |  |  |  +--rw source-ipv4-address src-ipv4-address inet:ipv4-address
 |        |        |  |  |  +--rw destination-ipv4-address dest-ipv4-address inet:ipv4-address
 |        |        |  |  |  +--rw protocol                    uint8
 |        |        |  |  |  +--rw ttl?                        uint8
 |        |        |  |  |  +--rw dscp?                       uint8
 |        |        |  |  +--:(ipv6)
 |        |        |  |     +--rw source-ipv6-address inet:ipv6-address
 |        |        |  |     +--rw destination-ipv6-address 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 outgoing-interface?         string
      +--:(logical-tunnel-next-hop) (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) {nexthop-tunnel}?
 |        |  +--rw tunnel-decap
 |        |     +--rw (tunnel-type)?
 |        |        +--:(ipv4) {ipv4-tunnel}?
 |        |        |  +--rw ipv4-decap
 |        |        |     +--rw ipv4-decap boolean
 |        |        |     +--rw ttl-action?   ttl-action-def
 |        |        +--:(ipv6) {ipv6-tunnel}?
 |        |        |  +--rw ipv6-decap
 |        |        |     +--rw ipv6-decap          boolean
 |        |        |     +--rw hop-limit-action? hop-limit-action-def
 |        |        +--:(mpls) {mpls-tunnel}?
 |        |           +--rw mpls-pop
 |        |              +--rw mpls-pop      boolean
 |        |              +--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)
 |        +--:(rib-name-nexthop)
 |           +--rw rib-name?                        string

               Figure 6 5: Nexthop Chain Base Structure

2.5.  Notifications

   Asynchronous notifications are sent by  RPC Operations

   This module defines the RIB manager of following RPC operations:

   o  rib-add: It is defined to add a network
   device rib to an external entity when some event triggers on the network
   device. a routing instance.  A RIB data-model MUST support sending 2 kind name
      of asynchronous
   notifications.

   1.  Route change notification:

   o Installed (Indicates the rib, address family of the rib and whether the route got installed in RPF check is
      enabled are passed as the FIB) ; input parameters.  The output is the
      result of the add operation: 1 means success, and 0 means failed.

   o Active (Indicates whether  rib-delete: It is defined to delete a route rib from a routing instance.
      When a rib is fully resolved 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.

   o  route-add: It is defined to add a
   candidate for selection) ;

   o Reason - E.g.  Not authorized

   2.  Nexthop resolution status notification

   Nexthops can be fully resolved nexthops route or an unresolved nexthop. a set of routes to a
      rib.  A resolved rib name, the route prefix(es), route attributes, route
      vendor attributes and nexthop has adequate level are passed as the input parameters.
      The output is the result of information to send the
   outgoing packet towards add operation: 1 means success,
      and 0 means failed.  Before calling the destination by forwarding route-add rpc, it on an
   interface of a directly connected neighbor.

   An unresolved nexthop is something that requires
      required to call the RIB manager nh-add rpc to
   determine create and/or return 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 identifier.

   o  route-delete: It is
   address reachable by regular IP forwarding or by defined to delete a MPLS tunnel route or by
   both.  If a set of routes
      from a rib.  A name of the RIB manager cannot resolve rib and the nexthop, then route prefix(es) are passed
      as the
   nexthop remains in an unresolved state and input parameters.  The output is NOT a suitable
   candidate for installation in the FIB. result of the delete
      operation: 1 means success, and 0 means failed.

   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 the result of
      the update operation: 1 means success, and 0 means failed.

   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 identifier to the nexthop.
      The outputs include the result of the update operation (1 means
      success, and 0 means failed ) and the nexthop identifier that is
      allocated to the nexthop.

   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 structure tree of notifications rpcs is shown showing in the following figure.

 notifications:
    +---n nexthop-resolution-status-change

   rpcs:
      +---x rib-add
      |  +--ro nexthop input
      |  |  +--ro nexthop-id           uint32 rib-name               string
      |  |  +--ro (nexthop-type)?
    | rib-family             rib-family-def
      |     +--:(nexthop-base)  |  +--ro enable-ip-rpf-check?   boolean
      |  +--ro output
      |     +--ro nexthop-base result boolean
      +---x rib-delete
      |  +--ro input
      |  |  +--ro nexthop-chain* [nexthop-chain-id]
    | rib-name string
      |  +--ro output
      |     +--ro nexthop-chain-id     uint32 result boolean
      +---x route-add
      |  +--ro input
      |  |  +--ro (nexthop-chain-type)? rib-name string
      |  |  +--ro routes
      |  |     ...
      |  +--ro output
      |     +--:(nexthop-protection)     +--ro result boolean
      +---x route-delete
      |  +--ro input
      |  |  +--ro nexthop-protection-list* [nexthop-protection-id]
    | rib-name string
      |  |  +--ro nexthop-protection-id     uint32 routes
      |  |     ...
      |  +--ro nexthop-preference       nexthop-preference-def
    |  | output
      |     +--ro rw nexthop                  nexthop-ref result boolean
      +---x route-update
      |  +--ro input
      |     +--:(nexthop-load-balance)  |  +--ro rib-name                           string
      |  |  +--ro nexthop-lb (match-conditions)?
      |  |     +--:(match-route-prefix)
      |     +--ro nexthop-lbs* [nexthop-lbs-id]  |     |  ...
      |        +--ro nexthop-lbs-id       uint32  |     +--:(match-route-attributes)
      |  |        +--ro nhop-lb-weight     nhop-lb-weight-def     |  ...
      |  |        +--ro nexthop-lb-member nexthop-ref     +--:(match-vendor-route-attributes)
      |  |     +--:(nexthop-replicate)     |  ...
      |        +--ro nexthop-replicate  |     +--:(match-nexthop)
      |           +--ro nexthop-replicates* [nexthop-replicates-id]  |        ...
      |  +--ro nexthop-replicates-id     uint32
    | output
      |     +--ro nexthop-replicate?       nexthop-ref result boolean
      +---x nh-add
      |  +--ro nexthop-state     nexthop-state-def
    +---n route-change
       +--ro instance-name            string input
      |  |  +--ro rib-name              string
       +--ro rib-family               rib-family-def
       +--ro route-index              uint64
       +--ro route-type               route-type-def
       +--ro match
      |  |  +--ro (rib-route-type)? nexthop-id            uint32
      |     +--:(ipv4)  |  +--ro sharing-flag          boolean
      |  |  +--ro ipv4 (nexthop-type)?
      |  |     ...
      |     +--:(ipv6)
       |  +--ro output
      |     +--ro ipv6 result        boolean
      |     +--ro nexthop-id uint32
      +---x nh-delete
         +--ro input
         |     ...  +--ro rib-name              string
         |  +--ro (nexthop-context-or-id)?
         |     +--:(nexthop-context)
         |     +--:(mpls-route)     |  ...
         |     +--:(nexthop-identifier)
         |        ...
         +--ro mpls-label              uint32 output
            +--ro result boolean

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

                    Figure 7: Notifications Structure

3.  YANG Modules

   //<CODE BEGINS> file "i2rs rib@2015-10-17.yang"

   module i2rs-rib {
     namespace "urn:ietf:params:xml:ns:yang:i2rs-rib";
       // replace with iana namespace when assigned
       prefix "i2rs-rib";

     import ietf-inet-types {
       prefix inet;
       //rfc6991
     }

     import ietf-interfaces {
       prefix "if";
     }

     import ietf-yang-types {
       prefix yang;
     }

     organization
       "IETF I2RS WG";
     contact
        "email: wang_little_star@sina.com
         email: hari@packetdesign.com
         email: mach.chen@huawei.com
         email: amit.dass@ericsson.com
         email: sriganesh.kini@ericsson.com
         email: 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 "2015-10-17" {
       description "initial revision";
       reference "draft-ietf-i2rs-rib-info-model-07";
     }

     //Nexthhop related features
     feature nexthop-tunnel {
       description
         "This feature means that a node support
          tunnel nexhtop capability. The i2rs client
          can specify a tunnel nexthop to a route.";

     }

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

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

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

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

     //Tunnel encap related features
     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.";
     }

     //Identities and Type Definitions
     identity mpls-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-action";
        description
         "MPLS label stack operation: push.";
     }

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

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

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

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

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

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

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

     }

     typedef match-ip-route-type-def {
       type identityref {
         base "match-ip-route-type";
       }
       description
         "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 to the FIB, the
          nexthops that are resolved and have two highest
          preferences are selected.";
     }
     typedef nhop-lb-weight-def {
       type uint8 {
         range "1..99";
       }
       description
         "Nhop-lb-weight is a number between 1 and 99.";
     }

     //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.";
       }
       leaf route-type {
         type route-type-def;
         mandatory true;
         description
           "Route types, e.g., IPv4, IPv6, MPLS, MAC etc. route types.";

       }
       container match {
         description
           "The match condition specifies the
            kind of route (IPv4, MPLS, etc.)
            and the set of fields to match on.";
         choice rib-route-type {
           description
             "To match a route according to rib route type.";
           case ipv4 {
             description
               "IPv4 rib case.";
             container ipv4 {
               description
                 "IPv4 route match type.";
               leaf ipv4-route-type {
                 type match-ip-route-type-def;
                 mandatory true;
                 description
                   "Route match type, it could be:
                    match source, or
                    match destination, or
                    match source and destination.
                    ";
               }
               choice match-ip-route-type {
                 description
                   "To match a route according to match type.";
                 case dest-ipv4-address {
                   leaf dest-ipv4-prefix {
                     type inet:ipv4-prefix;
                     mandatory true;
                     description
                       "To match an IPv4 destination address.";
                   }
                 }
                 case src-ipv4-address {
                   leaf src-ipv4-prefix {
                     type inet:ipv4-prefix;
                     mandatory true;
                     description
                       "To match an IPv4 source address.";
                   }
                 }
                 case dest-src-ipv4-address {
                   container dest-src-ipv4-address {
                     description
                       "To match IPv4 source and destination addreses.";

                     leaf dest-ipv4-prefix {
                       type inet:ipv4-prefix;
                       mandatory true;
                       description
                         "The IPv4 destination address of
                          the match condition.";
                     }
                     leaf src-ipv4-prefix {
                       type inet:ipv4-prefix;
                       mandatory true;
                       description
                         "The IPv4 source address of
                          the match condition.";
                     }
                   }
                 }
               }
             }
           }
           case ipv6 {
             description
               "IPv6 rib case.";
             container ipv6 {
               description
                 "IPv6 route match type.";
               leaf ipv6-route-type {
                 type match-ip-route-type-def;
                 mandatory true;
                 description
                   "Route match type, it could be:
                    match source, or
                    match destination, or
                    match source and destination.
                    ";
               }
               choice match-ip-route-type {
                 description
                   "To match a route according to match type.";
                 case dest-ipv6-address {
                   leaf dest-ipv6-prefix {
                     type inet:ipv6-prefix;
                     mandatory true;
                     description
                       "To match an IPv6 destination address.";
                   }
                 }
                 case src-ipv6-address {
                   leaf src-ipv6-prefix {
                     type inet:ipv6-prefix;
                     mandatory true;
                     description
                       "To match an IPv6 source address.";
                   }
                 }
                 case dest-src-ipv6-address {
                   container dest-src-ipv6-address {
                     description
                       "To match the source and destination addreses.";
                     leaf dest-ipv6-prefix {
                       type inet:ipv6-prefix;
                       mandatory true;
                       description
                         "The IPv6 destination address of
                          the match condition.";
                     }
                     leaf src-ipv6-prefix {
                       type inet:ipv6-prefix;
                       mandatory true;
                       description
                         "The IPv6 source address of
                          the match condition.";
                     }
                   }
                 }
               }
             }
           }
           case mpls-route {
             description
               "MPLS rib case.";
             leaf mpls-label {
               type uint32 ;
               mandatory true;
               description
                 "The label used for matching.";
             }
           }
           case mac-route {
             description
               "MAC rib case.";
             leaf mac-address {
               type uint32 ;
               mandatory true;
               description
                 "The MAC address used for matching.";
             }

           }
           case interface-route {
             description
               "Interface rib case.";
             leaf interface-identifier {
               type if:interface-ref;
               mandatory true;
               description
                 "The interface used for matching.";
             }
           }
         }
       }
     }

     grouping route {
       description
         "The common attributes usesd 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              route-state-def
       +--ro {
           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             route-reason-def

                  Figure 7 Notifications

3.  YANG Modules

<CODE BEGINS> file "i2rs rib@2015-04-03.yang"

module i2rs-rib {
  namespace "urn:TBD1:params:xml:ns:yang:rt:i2rs:rib";
    // replace with iana namespace when assigned
    prefix "i2rs-rib";

  import ietf-inet-types
           type route-reason-def;
           config false;
           description
             "Indicate the route reason.";
         }
       }
       container route-attributes {
    prefix inet;
    //rfc6991
         description
           "Route attributes.";
         uses route-attributes;
       }

  import ietf-interfaces
       container route-vendor-attributes {
    prefix "if";
         description
           "Route vendor attributes.";
         uses route-vendor-attributes;
       }

  import ietf-routing
     }

     grouping nexthop {
    prefix "rt";
       description
         "The nexthop structure.";
       leaf nexthop-id {
         type uint32;
         mandatory true;
         description
           "The nexthop identifier of a nexthop.";
       }

  organization
    "TBD2";
  contact
     "email: wang_little_star@sina.com
      email: hari@packetdesign.com
      email: mach.chen@huawei.com
      email: amit.dass@ericsson.com
      email: sriganesh.kini@ericsson.com
      email: nitin_bahadur@yahoo.com";
       leaf sharing-flag {
         type boolean;
         mandatory true;
         description
    "This module defines
           "To indicate whether a YANG data model for
     Routing Information Base (RIB) that aligns
     with nexthop is sharable
            or non-sharable.
            1 - means sharable
            0 - means non-sharable.";
       }
       choice nexthop-type {
         description
           "Based on nexthop type to derive the I2RS RIB information model.
     ";

  revision "2015-04-03" nexthop.";
         case nexthop-base {
           container nexthop-base {
             description "initial revision";
    reference "draft-ietf-i2rs-rib-info-model-06";
               "A nexthop base container.";
             uses nexthop-base;
           }
         }
         case nexthop-chain {
           if-feature nexthop-chain;
           container nexthop-capacity{ nexthop-chain {
             description
               "A nexthop chain container.";
             list nexthop-chain {
               key "nexthop-chain-member-id";
               description
                 "A list of nexthop members of
                  a load nexthop chain.";
               leaf support-tunnel{ nexthop-chain-member-id {
                 type boolean; uint32;
                 mandatory true;
                 description
                   "A nexthop identifier that points
                    to a nexthop chain member.
                    A nexthop chain member is a nexthop.";
               }
    leaf support-chains{
      type boolean;
             }
    leaf support-list-of-list{
      type boolean;
           }
    leaf support-replication{
      type boolean;
         }
         case nexthop-protection {
           if-feature nexthop-protection;
           container nexthop-protection {
                   description
               "A protection nexthop container.";
             list nexthop-protection-list {
               key "nexthop-protection-member-id";
               description
                 "A list of nexthop protection
                  members of a load balance nexthop.";
               leaf support-weighted{ nexthop-protection-member-id {
                 type boolean; uint32;
                 mandatory true;
                 description
                   "A nexthop identifier that points
                    to a protection nexthop member.
                    A protection nexthop member is
                    a nexthop.";
               }
               leaf support-protection{ nexthop-preference {
                 type boolean; 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.";
               }
    leaf lookup-limit{
      type uint8;
             }
           }
         }
         case nexthop-load-balance {
           if-feature nexthop-load-balance;
           container nexthop-tunnel-encap-capacity{ nexthop-lb {
             description
               "A load balance nexthop container.";
             list nexthop-lbs {
               key "nexthop-lbs-member-id";
               description
                 "A list of nexthop load balance
                  members of a load balance nexthop.";
               leaf support-ipv4{ nexthop-lbs-member-id {
                 type boolean; uint32;
                 mandatory true;
                 description
                   "A nexthop identifier that points
                    to a load balance nexthop member.
                    A load balance nexthop member is
                    a nexthop.";
               }
               leaf support-ipv6{ nhop-lb-weight {
                 type boolean; nhop-lb-weight-def;
                 mandatory true;
                 description
                   "The weight of a nexthop of
                    the load balance nexthops.";
               }
    leaf support-mpls{
      type boolean;
             }
    leaf support-gre{
      type boolean;
           }
    leaf support-vxlan{
      type boolean;
         }
         case nexthop-replicates {
           if-feature nexthop-replicates;
           container nexthop-replicates {
             description
               "A nexthop replicates container.";
             list nexthop-replicates {
               key "nexthop-replicates-member-id";
               description
                 "A list of replicate nexthop members
                  that belong to the nexthop-replicates.";
               leaf support-nvgre{ nexthop-replicates-member-id {
                 type boolean; uint32;
                 description
                   "A nexthop identifier that points
                    to a replicates nexthop member.
                    A replicates nexthop member is a nexthop.";
               }
             }

  // Identities and Type Definitions
  identity mpls-action {
    description
      "The mpls-action. ";
           }

  identity push {
    base "mpls-action";
         }

  identity pop {
    base "mpls-action";
       }

  identity swap
     }
     grouping nexthop-base {
       description
         "The base "mpls-action";
  }

  typedef mpls-action-def nexthop content for a route.";
       choice nexthop-base-type {
         description
           "Based on nexthop chain type identityref {
      base "mpls-action";
    }
  }

  identity to select
            relevant nexthop chain member.";
         case special-nexthop {
           leaf special {
             type special-nexthop-def;
             description
      "special-nexthop. ";
               "A special nexthop.";
           }

  identity discard {
    base "special-nexthop";
         }

  identity discard-with-error
         case egress-interface-nexthop {
    base "special-nexthop";
  }

  identity receive
            leaf outgoing-interface {
    base "special-nexthop";
              type if:interface-ref;
              mandatory true;
              description
                "The nexthop is an outgoing interface.";
            }

  identity cos-value {
    base "special-nexthop";
         }

  typedef special-nexthop-def
         case ipv4-address-nexthop {
    type identityref
           leaf ipv4-address {
      base "special-nexthop";
             type inet:ipv4-address;
             mandatory true;
             description
               "The nexthop is an IPv4 address.";
           }
         }

  identity ip-route-type
         case ipv6-address-nexthop {
           leaf ipv6-address {
             type inet:ipv6-address;
             mandatory true;
             description
               "The ip route type. ";
  }

  identity src {
    base "ip-route-type"; nexthop is an IPv6 address.";
           }

  identity dest {
    base "ip-route-type";
         }

  identity dest-src
         case egress-interface-ipv4-nexthop {
    base "ip-route-type";
  }

  typedef ip-route-type-def
           container egress-interface-ipv4-address{
             leaf outgoing-interface {
               type identityref {
      base "ip-route-type";
    } if:interface-ref;
               mandatory true;
               description
                 "Name of the outgoing interface.";
             }

  identity rib-family
             leaf ipv4-address {
               type inet:ipv4-address;
               mandatory true;
               description
                 "The rib-family."; nexthop points to an interface with
                  an IPv4 address.";
             }

  identity ipv4-rib-family {
    base "rib-family";
             description
               "Egress-interface and ip address: This can be usesd
                in cases e.g.where the ip address is a link-local
                address.";
           }

  identity ipv6-rib-family {
    base "rib-family";
         }

  identity mpls-rib-family
         case egress-interface-ipv6-nexthop {
    base "rib-family";
  }
  identity ieee-mac-rib-family
           container egress-interface-ipv6-address {
    base "rib-family";
  }

  typedef rib-family-def
             leaf outgoing-interface {
               type identityref {
      base "rib-family";
    } if:interface-ref;
               mandatory true;
               description
                 "Name of the outgoing interface.";
             }

  identity route-type
             leaf ipv6-address {
               type inet:ipv6-address;
               mandatory true;
               description
                 "The route type. "; nexthop points to an interface with
                  an IPv6 address.";
             }

  identity ipv4-route {
    base "route-type";
             description
               "Egress-interface and ip address: This can be usesd
                in cases e.g.where the ip address is a link-local
                address.";
           }

  identity ipv6-route {
    base "route-type";
         }

  identity mpls-route
         case egress-interface-mac-nexthop {
    base "route-type";
  }

  identity ieee-mac
           container egress-interface-mac-address {
    base "route-type";
  }

  identity interface
             leaf outgoing-interface {
    base "route-type";
               type if:interface-ref;
               mandatory true;
               description
                 "Name of the outgoing interface.";
             }

  typedef route-type-def
             leaf ieee-mac-address {
               type identityref {
      base "route-type";
    }
  }

  identity tunnel-type { uint32;
               mandatory true;
               description
                 "The tunnel type."; nexthop points to an interface with
                  a specific mac-address.";
             }

  identity ipv4-tunnel {
    base "tunnel-type";
             description
      "IPv4 tunnel type";
               "The egress interface must be an ethernet
                interface. Address resolution is not required
                for this nexthop.";
           }

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

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

  identity gre-tunnel
           if-feature nexthop-tunnel;
           container tunnel-encap {
    base "tunnel-type";
             uses tunnel-encap;
             description
      "GRE
               "This can be an encap representing an IP tunnel type";
  }

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

  identity nvgre-tunnel
         }
         case tunnel-decap-nexthp {
    base "tunnel-type";
           if-feature nexthop-tunnel;
           container tunnel-decap {
             uses tunnel-decap;
             description
      "NVGRE
               "This is to specify decapsulating a tunnel type"; header.";
           }

  typedef tunnel-type-def
         }
         case logical-tunnel-nexthop {
    type identityref
           if-feature nexthop-tunnel;
           container logical-tunnel {
      base "tunnel-type";
             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).";
           }
         }

  identity route-state
         case rib-name-nexthop {
           leaf rib-name {
             type string;
             description
      "The
               "A nexthop pointing to a rib indicates that the
                route state.";
  }

  identity active {
    base "route-state"; lookup needs to continue in The specified
                rib.  This is a way to perform chained lookups.";
           }
  identity inactive {
    base "route-state";
         }

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

     }

  identity nexthop-state

     grouping route-vendor-attributes {
       description
      "The nexthop state.";
         "Route vendor attributes.";
     }

  identity resolved

     grouping logical-tunnel {
    base "nexthop-state";
  }

  identity unresolved
       description
         "A logical tunnel that is identified
          by a type and a tunnel name.";
       leaf tunnel-type {
    base "nexthop-state";
         type tunnel-type-def;
         mandatory true;
         description
           "A tunnel type.";
       }

  typedef nexthop-state-def
       leaf tunnel-name {
         type identityref {
      base "nexthop-state"; string;
         mandatory true;
         description
           "A tunnel name that points to a logical tunnel.";
       }
     }

  identity route-installed-state

     grouping ipv4-header {
       description
         "The route installed state. ";
  }

  identity uninstalled {
    base "route-installed-state";
  }

  identity Installed IPv4 header encapsulation information.";
       leaf source-ipv4-address {
    base "route-installed-state";
         type inet:ipv4-address;
         mandatory true;
         description
           "The source ip address of the header.";
       }

  typedef route-installed-state-def
       leaf destination-ipv4-address {
         type identityref {
      base "route-installed-state";
    } inet:ipv4-address;
         mandatory true;
         description
           "The destination ip address of the header.";
       }
  identity route-reason
       leaf protocol {
         type uint8;
         mandatory true;
         description
           "The reason protocol id of invalid route. "; the header.";
       }

  identity low-preference
       leaf ttl {
    base "route-reason";
         type uint8;
         description
      "Low preference";
           "The TTL of the header.";
       }

  identity unresolved-nexthop
       leaf dscp {
    base "route-reason";
         type uint8;
         description
      "Unresolved nexthop";
           "The DSCP field of the header.";
       }

  identity higher-metric
     }

     grouping ipv6-header {
    base "route-reason";
       description
      "Higher metric";
  }

  typedef route-reason-def
         "The IPv6 header encapsulation information.";
       leaf source-ipv6-address {
         type identityref {
      base "route-reason";
    } inet:ipv6-address;
         mandatory true;
         description
           "The source ip address of the header.";
       }

  typedef nexthop-preference-def
       leaf destination-ipv6-address {
         type inet:ipv6-address;
         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 destination ip address of the
       nexthops that are resolved and have two highest
       preferences are selected.";
    type uint8 {
      range "1..99"; header.";
       }
  }
  typedef nhop-lb-weight-def
       leaf next-header {
    description
      "Nhop-lb-weight is a number between 1 and 99.";
         type uint8 {
      range "1..99"; uint8;
         mandatory true;
         description
           "The next header of the IPv6 header.";
       }
       leaf traffic-class {
         type uint8;
         description
           "The traffic class value of the header.";
       }
  typedef nexthop-ref
       leaf flow-label {
         type leafref uint16;
         description
           "The flow label of the header.";
       }
       leaf hop-limit {
      path  "/i2rs-rib:routing-instance/i2rs-rib:rib-list" +
            "/i2rs-rib:route-list/i2rs-rib:nexthop/i2rs-rib:nexthop-id";
         type uint8;
         description
           "The hop limit the header.";
       }
     }

  //Groupings
     grouping route-prefix{ nvgre-header {
       description
         "The common attributes used NvGRE header encapsulation information.";
       choice nvgre-type {
         description
           "NvGRE can use eigher IPv4
            or IPv6 header for all routes"; encapsulation.";
         case ipv4 {
           uses ipv4-header;
         }
         case ipv6 {
           uses ipv6-header;
         }
       }
       leaf route-index virtual-subnet-id {
         type uint64 ; uint32;
         mandatory true;
         description
           "The subnet identifier of the NvGRE header.";
       }
       leaf route-type flow-id {
         type route-type-def ;
      mandatory true; uint16;
         description
           "The flow identifier of the NvGRE header.";
       }
    container match
     }

     grouping vxlan-header {
       description
         "The VxLAN encapsulation header information.";
       choice rib-route-type {
        case ipv4 vxlan-type {
         description
            "Match on destination IP address in the
           "NvGRE can use eigher IPv4 header";
          container ipv4{
            leaf ipv4-route-type
            or IPv6 header for encapsulation.";
         case ipv4 {
              type ip-route-type-def ;
              mandatory true;
           uses ipv4-header;
         }
            choice ip-route-type {
         case destination-ipv4-address ipv6 {
           uses ipv6-header;
         }
       }
       leaf destination-ipv4-prefix vxlan-identifier {
         type inet:ipv4-prefix;
                  mandatory true; uint32;
         description
           "The VxLAN identifier of the VxLAN header.";
       }
     }
              case source-ipv4-address
     grouping gre-header {
       description
         "The GRE encapsulation header information.";
       leaf source-ipv4-prefix gre-ip-destination {
         type inet:ipv4-prefix; inet:ipv4-address;
         mandatory true;
         description
           "The destination ip address of the GRE header.";
       }
              }
              case destination-source-ipv4-address {
                container destination-source-ipv4-address {
       leaf destination-ipv4-prefix gre-protocol-type {
         type inet:ipv4-prefix; inet:ipv4-address;
         mandatory true;
         description
           "The protocol type of the GRE header.";
       }
       leaf source-ipv4-prefix gre-key {
         type inet:ipv4-prefix;
                    mandatory true;
                  }
                }
              }
            } uint64;
         description
           "The GRE key of the GRE header.";
       }
     }
        case ipv6

     grouping mpls-header {
       description
         "The MPLS encapsulation header information.";
       choice mpls-action-type {
         description
            "Match
           "Based on destination IP address in the IPv6 header";
          container ipv6 action type to perform different operation.";
         case mpls-push {
           leaf ipv6-route-type mpls-push {
             type ip-route-type-def ; boolean;
             mandatory true;
             description
               "Push a MPLS label to the label stack.";
           }
            choice ip-route-type {
              case destination-ipv6-address {
           leaf destination-ipv6-prefix mpls-label {
             type inet:ipv6-prefix; uint32;
             mandatory true;
             description
               "The MPLS label to be pushed.";
           }
           leaf s-bit {
             type boolean;
             description
               "The s-bit of the label to be pushed. ";
           }
              case source-ipv6-address
           leaf tc-value {
             type uint8;
             description
               "The traffic class value of the label to be pushed.";
           }
           leaf source-ipv6-prefix ttl-value {
             type inet:ipv6-prefix;
                  mandatory true; uint8;
             description
               "The TTL value of the label to to be pushed.";
           }
         }
         case destination-source-ipv6-address {
                container destination-source-ipv6-address {
                  leaf destination-ipv6-prefix mpls-swap {
                    type inet:ipv6-prefix;
                    mandatory true;
                  }
           leaf source-ipv6-prefix mpls-swap {
             type inet:ipv6-prefix; boolean;
             mandatory true;
                  }
                }
              }
            }
          }
        }
        case mpls-route {
             description
            "Match on
               "Swap a MPLS label at the top of the MPLS label stack"; with another label.";
           }
           leaf mpls-label mpls-in-label  {
             type uint32 ; uint32;
             mandatory true;
          }
        }
        case mac-route {
             description
            "Match on MAC destination addresses
               "The in the ethernet header"; MPLS label.";
           }
           leaf mac-address mpls-out-label  {
             type uint32 ; uint32;
             mandatory true;
          }
        }
        case interface-route {
             description
            "Match on incoming interface of the packet";
               "The out MPLS label.";
           }
           leaf interface-identifier ttl-action {
             type if:interface-ref;
            mandatory true;
          } 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 route{ tunnel-encap{
       description
      "The common attributes usesd
         "Tunnel encapsulation inforamtion.";
       choice tunnel-type {
         description
           "Tunnel options for all routes";
    uses route-prefix;
    container nexthop{ next-hops.";
         case ipv4 {
           if-feature ipv4-tunnel;
           uses nexthop; ipv4-header;
         }
    container route-statistic{
      leaf route-state
         case ipv6 {
        type route-state-def ;
        config false;
           if-feature ipv6-tunnel;
           uses ipv6-header;
         }
      leaf route-installed-state
         case mpls {
        type route-installed-state-def ;
        config false;
           if-feature mpls-tunnel;
           uses mpls-header;
         }
      leaf route-reason
         case gre {
        type route-reason-def ;
        config false;
      }
           if-feature gre-tunnel;
           uses gre-header;
         }
    container route-attributes{
         case nvgre {
           if-feature nvgre-tunnel;
           uses route-attributes; nvgre-header;
         }
    container route-vendor-attributes{
         case vxlan {
           if-feature vxlan-tunnel;
           uses route-vendor-attributes; vxlan-header;
         }
       }
     }

     grouping nexthop tunnel-decap {
    leaf nexthop-id {
      mandatory true;
      type uint32;
    }
       description
         "Tunnel decapsulation inforamtion.";
       choice nexthop-type tunnel-type {
         description
           "Tunnel options for next-hops.";
         case nexthop-base ipv4 {
           if-feature ipv4-tunnel;
           container nexthop-base {
          list nexthop-chain {
            key "nexthop-chain-id";
            uses nexthop-chain-member;
          }
        }
      }

       case nexthop-protection ipv4-decap {
        list nexthop-protection-list {
            key "nexthop-protection-id";
             leaf nexthop-protection-id ipv4-decap {
              mandatory true;
               type uint32;
            }
           leaf nexthop-preference {
             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."; boolean;
               mandatory true;
             type nexthop-preference-def;
               description
                 "IPv4 decap operations.";
             }
             leaf nexthop ttl-action {
             mandatory true;
               type nexthop-ref; ttl-action-def;
               description
                 "The ttl actions:
                  no-action or copy to inner header.";
             }
             description
               "IPv4 decap.";
           }
         }
         case nexthop-load-balance ipv6 {
           if-feature ipv6-tunnel;
           container nexthop-lb ipv6-decap {
          list nexthop-lbs {
            key "nexthop-lbs-id";
             leaf nexthop-lbs-id ipv6-decap {
              mandatory true;
               type uint32;
            }
            leaf nhop-lb-weight { boolean;
               mandatory true;
              type nhop-lb-weight-def;
               description
                 "IPv6 decap operations.";
             }
             leaf nexthop-lb-member hop-limit-action {
              mandatory true;
               type nexthop-ref;
            } hop-limit-action-def;
               description
                 "The hop limit actions:
                  no-action or copy to inner header.";
             }
             description
               "IPv6 decap.";
           }
         }
         case nexthop-replicate mpls {
           if-feature mpls-tunnel;
           container nexthop-replicate mpls-pop {
          list nexthop-replicates{
            key "nexthop-replicates-id";
             leaf nexthop-replicates-id mpls-pop {
               type boolean;
               mandatory true;
              type uint32;
               description
                 "Pop a MPLS label from the label stack.";
             }
             leaf nexthop-replicate ttl-action {
               type nexthop-ref;
            } ttl-action-def;
               description
                 "The label ttl actions:
                  no-action or copy to inner label";
             }
             description
               "MPLS decap.";
           }
         }
       }
     }

     grouping nexthop-chain-member route-attributes {
       description
      "One nexthop content
         "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 route."; protocol for the purpose of this
            field.  It iss also known as administrative-distance.
            The lower the value, the higher the preference.";
       }
       leaf nexthop-chain-id{ local-only {
         type uint32; boolean ;
         mandatory true;
         description
           "Indicate whether the attributes is local only.";
       }
       container address-family-route-attributes{
         description
           "Address family related route attributes.";
         choice nexthop-chain-type route-type {
           description
             "Address family related route attributes.";
           case nexthop-chain-member-special ip-route-attributes {
        container nexthop-chain-member-special
           }
           case mpls-route-attributes {
           }
           case ethernet-route-attributes {
          leaf nexthop-chain-member-special{
            type special-nexthop-def;
           }
         }
       }

      case nexthop-chain-member-identifier{
        uses nexthop-chain-member-identifier;
     }

      case egress-interface-next-hop

     container routing-instance {
       description
           "Simple next-hop is specified as
         "Configuration of an outgoing interface,
            next-hop address or both."; 'i2rs' pseudo-protocol
          instance consists of a list of ribs.";
       leaf outgoing-interface name {
         type if:interface-ref; string;
         mandatory true;
         description
             "Name
           "A routing instance is identified by its name,
            INSTANCE_name. 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 outgoing name of a configured
              network layer interface.";
         }
       }

      case ipv4-address-next-hop {
       leaf next-hop-ipv4-address router-id {
         type inet:ipv4-address;
          mandatory true; yang:dotted-quad;
         description
            "The nexthop is an IPv4 address.";
        }
           "Router ID - 32-bit number in the form of a dotted quad.";
       }

      case ipv6-address-next-hop {
       leaf next-hop-ipv6-address lookup-limit {
         type inet:ipv6-address;
          mandatory true; uint8;
         description
            "The nexthop is an IPv6 address.";
        }
           "A limit on how many levels of a lookup can be performed.";
       }

      case egress-interface-ipv4-next-hop
       list rib-list {
        container next-hop-egress-interface-ipv4-address{
         key "name";
         description
           "This is the list of RIBs associated with this routing
            instance. Each routing instance can have multiple RIBs
            to represent routes of different types.";
         leaf outgoing-interface name {
           type if:interface-ref; string;
           mandatory true;
           description
              "Name of
             "A reference to the outgoing interface."; name of a rib.";
         }
         leaf next-hop-egress-ipv4-address rib-family {
           type inet:ipv4-address; rib-family-def;
           mandatory true;
           description
             "The nexthop points to an interface with
               an IPv4 address."; address family of the rib.";
         }
         leaf enable-ip-rpf-check {
           type boolean;
           description
            "Egress-interface and ip address: This
             "Each RIB can be usesd optionally associated with a
              ENABLE_IP_RPF_CHECK attribute that enables Reverse
              path forwarding (RPF) checks on all IP routes in cases e.g.where the ip address that
              RIB.  Reverse path forwarding (RPF) check is used to
              prevent spoofing and limit malicious traffic.";
         }
         list route-list {
           key "route-index";
           description
             "A routes of a link-local
             address."; rib.";
           uses route;
         }
       }

      case egress-interface-ipv6-next-hop
     }

     /*RPC Operations*/

     rpc rib-add {
       description
         "To add a rib to a instance";
       input {
        container next-hop-egress-interface-ipv6-address{
         leaf outgoing-interface rib-name {
           type if:interface-ref; string;
           mandatory true;
           description
              "Name
             "A reference to the name of the outgoing interface."; rib
              that is to be added.";
         }
         leaf next-hop-egress-ipv6-address rib-family {
           type inet:ipv6-address; rib-family-def;
           mandatory true;
           description
             "The nexthop points to an interface with
               an IPv6 address."; address family of the rib.";
         }
         leaf enable-ip-rpf-check {
           type boolean;
           description
            "Egress-interface and ip address: This
             "Each RIB can be usesd
             in cases e.g.where the ip address 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 a link-local
             address."; used to
              prevent spoofing and limit malicious traffic.";
         }
       }

      case egress-interface-mac-next-hop

       output {
        container next-hop-egress-interface-mac-address{
         leaf outgoing-interface result {
           type if:interface-ref; boolean ;
           mandatory true;
           description
              "Name
             "Return the result of the outgoing interface."; rib-add operation.
              1 - means success;
              0 - means falied.";
         }
       }
     }

     rpc rib-delete {
       description
         "To delete a rib from a routing instance,
          by deleting the rib, all routes installed
          in the rib will be deleted as well.";
       input {
         leaf ieee-mac-address rib-name {
           type uint32; string;
           mandatory true;
           description
              "The nexthop points
             "A reference to an interface with
               a specific mac-address.";

          }
          description
            "The egress interface must be an ethernet
             interface.Address resolution the name of the rib
              that is not required
             for this nexthop." to be deleted.";
         }
       }

      case tunnel-encap-next-hop
       output {
        container tunnel-encap {
          uses tunnel-encap;
         leaf outgoing-interface result {
           type string;
          } boolean ;
           mandatory true;
           description
            "This can be an encap representing an ip tunnel or
             mpls tunnel or others as defined in this document.
             An optional egress interface can be specified to
             indicate which interface to send The packet out on.
             The egress interface is usesful when
             "Return the network
             device contains eThernet interfaces and one needs
             to perform address resolution for The ip packet."; result of the rib-delete operation.
              1 - means success;
              0 - means falied.";
         }
       }

      case logical-tunnel-next-hop {
        container logical-tunnel
     }

     rpc route-add {
          uses logical-tunnel;
       description
            "This can be
         "To add a MPLS LSP route or a GRE tunnel (or others
             as defined in This document), that is represented
             by list of route to a unique identifier (e.g. name).";
        }
      }

      case rib-name rib";
       input {
         leaf rib-name {
           type string;
           mandatory true;
           description
             "A nexthop pointing reference to a rib indicates that the
               route lookup needs name of a rib.";
         }
         container routes {
           description
             "The routes to continue in The specified
               rib.  This is be added to the rib.";
           list route-list {
             key "route-index";
             description
               "Use a way list to perform chained lookups.";
        } include all routes to be added.";

             uses route-prefix;
             uses route-attributes;
             uses route-vendor-attributes;
             uses nexthop;
           }
         }
       }
  grouping nexthop-chain-member-identifier{
    choice nexthop-identifier-type{
      case nexthop-chain-name

       output {
         leaf nexthop-chain-name result {
           type string; boolean ;
           mandatory true;
           description
             "Return the result of the route-add operation.
              1 - means success;
              0 - means falied.";
         }
       }
      case nexthop-chain-id
     }

     rpc route-delete {
        leaf nexthop-chain-id
       description
         "To delete a route or a list of route from a rib";
       input {
          type uint32;
          mandatory true;
        }
      }
    }
  }

  grouping route-vendor-attributes{
  }

  grouping logical-tunnel{
         leaf tunnel-type rib-name {
           type tunnel-type-def ; string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
    leaf tunnel-name
         container routes {
      type string ;
      mandatory true;
           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;
           }
         }

  grouping ipv4-header{
    leaf source-ipv4-address {
      type inet:ipv4-address;
      mandatory true;
       }
    leaf destination-ipv4-address

       output {
      type inet:ipv4-address;
      mandatory true;
    }
         leaf protocol result {
           type uint8; boolean ;
           mandatory true;
           description
             "Return the result of the route-delete operation.

              1 - means success;
              0 - means falied.";
         }
    leaf ttl {
      type uint8;
    }
    leaf dscp {
      type uint8;
       }
     }

  grouping ipv6-header{
    leaf source-ipv6-address

     rpc route-update {
      type inet:ipv6-address;
      mandatory true;
    }
    leaf destination-ipv6-address
       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, or
              c. nexthop;
            2. The update parameters to be used:
              a. new nexhop;
              b. new route attributes;
          Actions:
            1. update the nexthop
            2. update the route attributes
          The outputs:
            1 - success;
            0 - failed.
          ";

       input {
      type inet:ipv6-address;
      mandatory true;
    }
         leaf next-header rib-name {
           type uint8; string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
    leaf traffic-class {
      type uint8;
    }
    leaf flow-label {
      type uint16;
    }
    leaf hop-limit {
      type uint8;
    }
  }

  grouping nvgre-header{
         choice nvgre-type match-conditions {
           description
        "nvgre-header.";
      case ipv4 {
        uses ipv4-header;
      }
             "When conditions matched, update the routes.";
           //Update routes that have the matched route prefixes
           case ipv6 match-route-prefix {
        uses ipv6-header;
      }
    }
    leaf virtual-subnet-id
             container input-routes {
      type uint32;
      mandatory true;
    }
    leaf flow-id
               description
                 "The matched routes to be updated.";
               list route-list {
      type uint16;
    }
  }
  grouping vxlan-header{
                 key "route-index";
                 description
                   "The list of routes to be updated.";
                 uses route-prefix;
                 choice vxlan-type update-actions-prefix {
                   description
        "vxlan-header.";
                     "Update actions include:

                      1. update nexthop
                      2. update route attributes
                      3. update route-vendor-attributes.
                      ";
                   case ipv4 update-nexthop {
                     uses ipv4-header; nexthop;
                   }
                   case ipv6 update-route-attributes {
                     uses ipv6-header;
      } route-attributes;
                   }
    leaf vxlan-identifier
                   case update-route-vendor-attributes {
      type uint32;
                     uses route-vendor-attributes;
                   }
                 }

  grouping gre-header{
    leaf gre-ip-destination {
      type inet:ipv4-address;
      mandatory true;
               }
    leaf gre-protocol-type {
      type inet:ipv4-address;
      mandatory true;
             }
    leaf gre-key {
      type uint64;
           }
           //Update the routes that have the matched attributes
           case match-route-attributes {
             container input-route-attributes {
               description
                 "The route attributes are used for matching.";
               uses route-attributes;
             }

  grouping mpls-header{
             choice mpls-action-type update-actions-attributes {
               description
        "mpls-header.";
                 "Update actions include:
                  1. update nexthop
                  2. update route attributes
                  3. update route-vendor-attributes.
                  ";
               case mpls-push {
        leaf mpls-push {
          type boolean;
          mandatory true;
        }
        leaf mpls-label update-nexthop {
          type uint32;
          mandatory true;
                 uses nexthop;
               }
        leaf s-bit
               case update-route-attributes {
          type boolean;
                 uses route-attributes;
               }
        leaf tos-value
               case update-route-vendor-attributes {
          type uint8;
                 uses route-vendor-attributes;
               }
        leaf ttl-value {
          type uint8;
             }
           }
           //Update the routes that have the matched vendor attributes
           case mpls-pop {
        leaf mpls-pop {
          type boolean;
          mandatory true;
        }
        leaf ttl-action match-vendor-route-attributes {
          type uint8;
        }
      }
    }
  }

  grouping tunnel-encap{
    choice tunnel-type
             container input-vendor-route-attributes {
               description
        "options
                 "The vendor route attributes are used for next-hops.";
      case ipv4 { matching.";
               uses ipv4-header; route-vendor-attributes;

             }
      case ipv6
             choice update-actions-vendor-attributes {
        uses ipv6-header;
      }
               description
                 "Update actions include:
                  1. update nexthop
                  2. update route attributes
                  3. update route-vendor-attributes.
                  ";
               case mpls update-nexthop {
                 uses mpls-header; nexthop;
               }
               case gre update-route-attributes {
                 uses gre-header; route-attributes;
               }
               case nvgre update-route-vendor-attributes {
                  uses nvgre-header; route-vendor-attributes;
               }
             }
           }

  grouping route-attributes{
    leaf route-preference {
      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,
           //Update the higher routes that have the preference.";

        type uint32 ;
      mandatory true;
    }
    leaf local-only matched nexthop
           case match-nexthop {
      type boolean ;
      mandatory true;
             container input-nexthop {
               description
                 "The nexthop used for matching.";
               uses nexthop;
             }
    container address-family-route-attributes{

             choice route-type update-actions-nexthop {
               description
                 "Update actions include:
                  1. update nexthop
                  2. update route attributes
                  3. update route-vendor-attributes.
                  ";
               case ip-route-attributes update-nexthop {
                 uses nexthop;
               }
               case mpls-route-attributes update-route-attributes {
                 uses route-attributes;
               }
               case ethernet-route-attributes update-route-vendor-attributes {
                  uses route-vendor-attributes;
               }
             }
           }
         }

  container routing-instance
       }
       output {
    description
      "Configuration of an 'i2rs' pseudo-protocol instance
       consists of a list of ribs.";
         leaf name result {
      description
        "A routing instance is identified by its name,
        INSTANCE_name.  This MUST be unique across all routing
        instances in a given network device.";
           type string boolean ;
           mandatory true;
    }
    list interface-list {
           description
        "This represents the list of interfaces associated
         with this routing instance.  The interface list helps
         constrain
             "Return the boundaries result of packet forwarding.
         Packets coming on these interfaces are directly
         associated with the given routing instance.  The
         interface list contains route-update operation.
              1 - means success;
              0 - means falied.";
         }
       }
     }

     rpc nh-add {
       description
         "To add a list of identifiers, with
         each identifier uniquely identifying an interface.";
      key "name";
      leaf nexthop to a rib.
          Inputs parameters:
            1. rib name
            2. nexthop;
          Actions:
            Add the nexthop to the rib
          Outputs:
            1.Operation result:
              1 - means success
              0 - means faled;
            2. nexthop identifier.";
       input {
         leaf rib-name {
           type if:interface-ref; string;
           mandatory true;
           description
             "A reference to the name of a configured network layer
         interface.";
      } rib.";
         }
         uses rt:router-id ;
    list rib-list nexthop;
       }

       output {
         leaf result {
           type boolean ;
           mandatory true;
           description
        "This is
             "Return the list result of RIBs associated with this routing
         instance.  Each routing instance can have multiple RIBs the nh-add operation.
              1 - means success;
              0 - means falied.";
         }
         leaf nexthop-id {
           type uint32;
           mandatory true;
           description
             "A nexthop identifer that is allocated to represent routes of different types.";
      key "name"; the nexthop.";
         }
       }
     }

     rpc nh-delete {
       description
         "To delete a nexthop from a rib";
       input {
         leaf name rib-name {
           type string;
           mandatory true;
           description
             "A reference to the name of a rib.";
         }
         choice nexthop-context-or-id {
           description
             "Delete a nexthop by inputing
              the nexthop itself or its nexthop id.";
           case nexthop-context {
             uses nexthop;
           }
           case nexthop-identifier {
             leaf nexthop-identifer {
               type string; uint32;
               mandatory true;
               description
                 "A reference to the nexthop to be deleted.";
             }
           }
         }
       }

       output {
         leaf rib-family result {
           type rib-family-def; boolean ;
           mandatory true;
      }
      leaf enable-ip-rpf-check {
           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.";
        type boolean;
      }
      list route-list{
        key "route-index";
        uses route;
             "Return the result of the nh-delete operation.
              1 - means success;
              0 - means falied.";
         }
       }
     }

     /*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.";
      type nexthop-state-def;
      mandatory true;
       }
     }

     notification route-change {
       description
         "Route change notification.";
       leaf instance-name rib-name {
      description
        "A routing instance is identified by its name,
        INSTANCE_name.  This MUST be unique across all
        routing instances in a given network device.";
         type string ; string;
         mandatory true;
    }
    leaf rib-name {
         description
           "A reference to the name of a rib.";
      type string;
      mandatory true;
       }
       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.";
      type route-installed-state-def;
      mandatory true;
       }
       leaf route-state {
         type route-state-def;
         mandatory true;
         description
           "Indicates whether a route is fully resolved and
            is a candidate for selection.";
      type route-state-def;
      mandatory true;
       }
       leaf route-reason route-change-reason {
      description
       "Need to be added.";
         type route-reason-def;
         mandatory true;
         description
           "Return the reason that causes the route change.";
       }
     }
   }

<CODE

   //<CODE ENDS>

4.  IANA Considerations

   TBD.

   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

6.1.

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>.

6.2.

   [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., Folkes, R., Kini, S., and J. Medved, "Routing Information
              Base Info Model", draft-ietf-i2rs-rib-info-
              model-06 draft-ietf-i2rs-rib-info-model-07 (work
              in progress), March September 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.

   [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>.

   [RFC6021]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6021, DOI 10.17487/RFC6021, October 2010,
              <http://www.rfc-editor.org/info/rfc6021>.

Authors' Addresses

   Lixing Wang
   Huawei
   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