IS-IS Working Group                                         S. Litkowski
Internet-Draft                                                    Orange
Intended status: Standards Track                                D. Yeung
Expires: September 30, October 1, 2017                                     Arrcus, Inc
                                                               A. Lindem
                                                           Cisco Systems
                                                                J. Zhang
                                                        Juniper Networks
                                                               L. Lhotka
                                                                  CZ.NIC
                                                          March 29, 30, 2017

                   YANG Data Model for IS-IS protocol
                    draft-ietf-isis-yang-isis-cfg-16
                    draft-ietf-isis-yang-isis-cfg-17

Abstract

   This document defines a YANG data model that can be used to configure
   and manage IS-IS protocol on network elements.

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 [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/.

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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 30, October 1, 2017.

Copyright Notice

   Copyright (c) 2017 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Tree diagram  . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Design of the Data Model  . . . . . . . . . . . . . . . . . .   3
     2.1.  IS-IS Configuration . . . . . . . . . . . . . . . . . . .  11
     2.2.  Multitopology Parameters  . . . . . . . . . . . . . . . .  11
     2.3.  Per-Level Parameters  . . . . . . . . . . . . . . . . . .  12  11
     2.4.  Per-Interface Parameters  . . . . . . . . . . . . . . . .  13
     2.5.  Authentication Parameters . . . . . . . . . . . . . . . .  16
     2.6.  IGP/LDP synchronization . . . . . . . . . . . . . . . . .  16
     2.7.  ISO parameters  . . . . . . . . . . . . . . . . . . . . .  16
     2.8.  IP FRR  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     2.9.  Operational States  . . . . . . . . . . . . . . . . . . .  17
   3.  RPC Operations  . . . . . . . . . . . . . . . . . . . . . . .  17
   4.  Notifications . . . . . . . . . . . . . . . . . . . . . . . .  18
   5.  Interaction with Other YANG Modules . . . . . . . . . . . . .  22
   6.  IS-IS YANG Module . . . . . . . . . . . . . . . . . . . . . .  23
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . 101  99
   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . . 102 100
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 102 100
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 102 100
   11. Change log for ietf-isis YANG module  . . . . . . . . . . . . 102 100
     11.1.  From version -16 to version -17  . . . . . . . . . . . . 100
     11.2.  From version -15 to version -16  . . . . . . . . . . . . 102
     11.2. 100
     11.3.  From version -14 to version -15  . . . . . . . . . . . . 102
     11.3. 101
     11.4.  From version -13 to version -14  . . . . . . . . . . . . 103
     11.4. 101
     11.5.  From version -12 to version -13  . . . . . . . . . . . . 103
     11.5. 101
     11.6.  From version -09 to version -12  . . . . . . . . . . . . 103
     11.6. 101
     11.7.  From version -08 to version -09  . . . . . . . . . . . . 103
     11.7. 102
     11.8.  From version -07 to version -08  . . . . . . . . . . . . 104
     11.8. 102
     11.9.  From version -05 to version -07  . . . . . . . . . . . . 104
     11.9. 102
     11.10. From version -03 to version -05  . . . . . . . . . . . . 104
     11.10. 102
     11.11. From version -02 to version -03  . . . . . . . . . . . . 104
     11.11. 103
     11.12. From version -01 to version -02  . . . . . . . . . . . . 105
     11.12. 103
     11.13. From version -00 to version -01  . . . . . . . . . . . . 105 103
   12. Normative References  . . . . . . . . . . . . . . . . . . . . 106 104
   Appendix A.  Example of IS-IS configuration in XML  . . . . . . . 107 105
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 109 107

1.  Introduction

   This document defines a YANG data model for IS-IS routing protocol.

   The data model covers configuration of an IS-IS routing protocol
   instance as well as operational states.

1.1.  Tree diagram

   A simplified graphical representation of the data model is presented
   in Section 2.

   The meaning of the symbols in these diagrams is as follows:

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

   o  Curly braces "{" and "}" contain names of optional features that
      make the corresponding node conditional.

   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" or "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.  Design of the Data Model

   The IS-IS YANG module is divided in two main "isis" containers that
   are augmenting the "control-plane-protocol" lists in ietf-routing
   module with specific IS-IS parameters.

   One container contains the writable parameters, while the other
   contains the operational states.

   The figure below describes the overall structure of the isis YANG
   module:

module: ietf-isis
augment /rt:routing-state/rt:ribs/rt:rib/rt:routes/rt:route:
   +--ro metric?       uint32
   +--ro tag*          uint64
   +--ro route-type?   enumeration
augment /if:interfaces/if:interface:
   +--rw clns-mtu?   uint16
augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol
:
   +--rw isis
      +--rw enable?                   boolean {admin-control}?
      +--rw level-type?               level
      +--rw system-id?                system-id
      +--rw maximum-area-addresses?   uint8 {maximum-area-addresses}?
      +--rw area-address*             area-address
      +--rw mpls
      |  +--rw ipv4-router-id?   inet:ipv4-address {ipv4-router-id}?
      |  +--rw ipv6-router-id?   inet:ipv6-address {ipv6-router-id}?
      |  +--rw ldp
      |        ...
      +--rw auto-cost {auto-cost}?
      |  +--rw reference-bandwidth?   uint32
      |  +--rw enable?                boolean
      +--rw lsp-mtu?                  uint16
      +--rw lsp-lifetime?             uint16
      +--rw lsp-refresh?              uint16 {lsp-refresh}?
      +--rw spf-control
      |  +--rw ietf-spf-delay {ietf-spf-delay}?
      |        ...              rt-types:timer-value-seconds16 {ls
p-refresh}?
      +--rw graceful-restart {graceful-restart}?
      |  +--rw enable?             boolean
      |  +--rw restart-interval?   uint16   rt-types:timer-value-seconds16
      |  +--rw helper-enable?      boolean
      +--rw nsr {nsr}?
      |  +--rw enable?   boolean
      +--rw node-tags {node-tag}?
      |  +--rw node-tag* [tag]
      |        ...
      +--rw authentication
      |  +--rw (authentication-type)?
      |  |     ...
      |  +--rw level-1
      |  |     ...
      |  +--rw level-2
      |        ...
      +--rw metric-type
      |  +--rw value?     enumeration
      |  +--rw level-1
      |  |     ...

      |  +--rw level-2
      |        ...
      +--rw default-metric
      |  +--rw value?     wide-metric
      |  +--rw level-1
      |  |     ...
      |  +--rw level-2
      |        ...
      +--rw afs {nlpid-control}?
      |  +--rw af* [af]
      |        ...
      +--rw preference
      |  +--rw (granularity)?
      |        ...
      +--rw overload
      |  +--rw status?   boolean
      +--rw overload-max-metric {overload-max-metric}?
      |  +--rw timeout?   uint16   rt-types:timer-value-seconds16
      +--rw fast-reroute {fast-reroute}?
      |  +--rw lfa {lfa}?
      +--rw spf-control
      |  +--rw ietf-spf-delay {ietf-spf-delay}?
      |        ...
      +--rw topologies {multi-topology}?
      |  +--rw topology* [name]
      |        ...
      +--rw interfaces
         +--rw interface* [name]
               ...
augment /rt:routing-state/rt:control-plane-protocols/rt:control-plane-pr
otocol:
   +--ro isis
      +--ro enable?                   boolean {admin-control}?
      +--ro level-type?               level
      +--ro system-id?                system-id
      +--ro maximum-area-addresses?   uint8 {maximum-area-addresses}?
      +--ro area-address*             area-address
      +--ro mpls
      |  +--ro ipv4-router-id?   inet:ipv4-address {ipv4-router-id}?
      |  +--ro ipv6-router-id?   inet:ipv6-address {ipv6-router-id}?
      |  +--ro ldp
      |        ...
      +--ro auto-cost {auto-cost}?
      |  +--ro reference-bandwidth?   uint32
      |  +--ro enable?                boolean
      +--ro lsp-mtu?                  uint16
      +--ro lsp-lifetime?             uint16
      +--ro lsp-refresh?              uint16 {lsp-refresh}?
      +--ro spf-control
      |  +--ro ietf-spf-delay {ietf-spf-delay}?
      |        ...              rt-types:timer-value-seconds16 {ls
p-refresh}?
      +--ro graceful-restart {graceful-restart}?
      |  +--ro enable?             boolean
      |  +--ro restart-interval?   uint16   rt-types:timer-value-seconds16
      |  +--ro helper-enable?      boolean
      +--ro nsr {nsr}?
      |  +--ro enable?   boolean
      +--ro node-tags {node-tag}?
      |  +--ro node-tag* [tag]
      |        ...
      +--ro authentication
      |  +--ro (authentication-type)?
      |  |     ...
      |  +--ro level-1
      |  |     ...
      |  +--ro level-2
      |        ...
      +--ro metric-type
      |  +--ro value?     enumeration
      |  +--ro level-1
      |  |     ...
      |  +--ro level-2
      |        ...
      +--ro default-metric
      |  +--ro value?     wide-metric
      |  +--ro level-1
      |  |     ...
      |  +--ro level-2
      |        ...
      +--ro afs {nlpid-control}?
      |  +--ro af* [af]
      |        ...
      +--ro preference
      |  +--ro (granularity)?
      |        ...
      +--ro overload
      |  +--ro status?   boolean
      +--ro overload-max-metric {overload-max-metric}?
      |  +--ro timeout?   uint16   rt-types:timer-value-seconds16
      +--ro fast-reroute {fast-reroute}?
      |  +--ro lfa {lfa}?
      |  +--ro protected-routes
      |  |     ...
      |  +--ro nonprotected-routes
      |  |     ...
      |  +--ro protection-statistics* [frr-protection-method]
      |        ...
      +--ro ietf-spf-delay {ietf-spf-delay}?
      |  +--ro initial-delay?             uint16
      |  +--ro short-delay?               uint16
      |  +--ro long-delay?                uint16
      |  +--ro hold-down?                 uint16
      |  +--ro time-to-learn?             uint16
      |  +--ro current-state?             enumeration spf-control
      |  +--ro remaining-time-to-learn?   uint16 ietf-spf-delay {ietf-spf-delay}?
      |        ...

      +--ro remaining-hold-down?       uint16 topologies* [name]
      |  +--ro last-event-received?       yang:timestamp name         leafref
      |  +--ro next-spf-time?             yang:timestamp local-rib
      |  +--ro last-spf-time?             yang:timestamp        ...
      +--ro local-rib
      |  +--ro route* [prefix]
      |        ...
      +--ro topologies* [name]
      |  +--ro name         leafref
      |  +--ro local-rib
      |        ...
      +--ro system-counters
      |  +--ro level* [level]
      |        ...
      +--ro interfaces
      |  +--ro interface* [interface]
      |        ...
      +--ro spf-log
      |  +--ro event* [id]
      |        ...
      +--ro lsp-log
      |  +--ro event* [id]
      |        ...
      +--ro database hostnames
      |  +--ro level-db* [level] hostname* [system-id]
      |        ...
      +--ro hostnames database
         +--ro hostname* [system-id] level-db* [level]
               ...
rpcs:
   +---x clear-adjacency
   |  +--ro input
   |     +--ro routing-protocol-instance-name    instance-state-ref
   |     +--ro level?                            level
   |     +--ro interface?                        string
   +---x clear-database
      +--ro input
         +--ro routing-protocol-instance-name    instance-state-ref
         +--ro level?                            level
notifications:
   +---n database-overload
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro overload?                enumeration
   +---n lsp-too-large
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro pdu-size?                uint32
   |  +--ro lsp-id?                  lsp-id
   +---n if-state-change
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro state?                   if-state-type
   +---n corrupted-lsp-detected
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro lsp-id?                  lsp-id
   +---n attempt-to-exceed-max-sequence
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro lsp-id?                  lsp-id
   +---n id-len-mismatch
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro pdu-field-len?           uint8
   |  +--ro raw-pdu?                 binary
   +---n max-area-addresses-mismatch
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro max-area-addresses?      uint8
   |  +--ro raw-pdu?                 binary
   +---n own-lsp-purge
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro lsp-id?                  lsp-id
   +---n sequence-number-skipped
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro lsp-id?                  lsp-id
   +---n authentication-type-failure
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro raw-pdu?                 binary
   +---n authentication-failure
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro raw-pdu?                 binary
   +---n version-skew
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro protocol-version?        uint8
   |  +--ro raw-pdu?                 binary
   +---n area-mismatch
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro raw-pdu?                 binary
   +---n rejected-adjacency
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro raw-pdu?                 binary
   |  +--ro reason?                  string
   +---n protocols-supported-mismatch
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro raw-pdu?                 binary
   |  +--ro protocols*               uint8
   +---n lsp-error-detected
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro lsp-id?                  lsp-id
   |  +--ro raw-pdu?                 binary
   |  +--ro error-offset?            uint32
   |  +--ro tlv-type?                uint8
   +---n adjacency-state-change
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro neighbor?                string
   |  +--ro neighbor-system-id?      system-id
   |  +--ro state?                   adj-state-type
   |  +--ro reason?                  string
   +---n lsp-received
   |  +--ro routing-instance?        string
   |  +--ro routing-protocol-name?   string
   |  +--ro isis-level?              level
   |  +--ro interface-name?          string
   |  +--ro interface-level?         level
   |  +--ro extended-circuit-id?     extended-circuit-id
   |  +--ro lsp-id?                  lsp-id
   |  +--ro sequence?                uint32
   |  +--ro received-timestamp?      yang:timestamp
   |  +--ro neighbor-system-id?      system-id
   +---n lsp-generation
      +--ro routing-instance?        string
      +--ro routing-protocol-name?   string
      +--ro isis-level?              level
      +--ro lsp-id?                  lsp-id
      +--ro sequence?                uint32
      +--ro send-timestamp?          yang:timestamp

2.1.  IS-IS Configuration

   The IS-IS configuration container is divided in:

   o  Global parameters.

   o  Per interface configuration (see Section 2.4).

   Additional modules may be created this to support any additional
   parameters.  These additional modules should augment the ietf-isis
   module.

   The model implements features, thus some of the configuration
   statement becomes optional.  As an example, the ability to control
   the administrative state of a particular IS-IS instance is optional.
   By advertising the feature "admin-control", a device communicates to
   the client that it supports the ability to shutdown a particular IS-
   IS instance.

   The global configuration contains usual IS-IS parameters such as lsp-
   mtu, lsp-lifetime, lsp-refresh, default-metric...

2.2.  Multitopology Parameters

   The model supports multitopology (MT) IS-IS as defined in [RFC5120].

   The "topologies" container is used to enable support of MT
   extensions.

   The "name" used in the topology list should refer to an existing RIB
   of the device.

   Some specific parameters could be defined on a per topology basis
   both at global level and at interface level: for example, an
   interface metric can be defined per topology.

   Multiple address families (like IPv4 or IPv6) can also be activated
   within the default topology.  This can be achieved using the "afs"
   container (requiring "nlpid-control" feature to be advertised).

2.3.  Per-Level Parameters

   Some parameters allow a per level configuration.  In this case, the
   parameter is modeled as a container with three configuration
   locations:

   o  a top level container: corresponds to level-1-2, so the
      configuration applies to both levels.

   o  a level-1 container: corresponds to level-1 specific parameters.

   o  a level-2 container: corresponds to level-2 specific parameters.

               +--rw priority
               |  +--rw value?     uint8
               |  +--rw level-1
               |  |  +--rw value?   uint8
               |  +--rw level-2
               |     +--rw value?   uint8

   Example:

           <priority>
               <value>250</value>
               <level-1>
                   <value>100</value>
               </level-1>
               <level-2>
                   <value>200</value>
               </level-2>
           </priority>

   An implementation SHOULD prefer a level specific parameter over a
   level-all parameter.  As example, if the priority is 100 for the
   level-1, 200 for the level-2 and 250 for the top level configuration,
   the implementation should use 100 for the level-1 and 200 for the
   level-2.

   Some parameters like "overload bit" and "route preference" are not
   modeled to support a per level configuration.  If an implementation
   supports per level configuration for such parameter, this
   implementation SHOULD augment the current model by adding both
   level-1 and level-2 containers and SHOULD reuse existing
   configuration groupings.

   Example of augmentation:

   augment "/rt:routing/" +
           "rt:control-plane-protocols/rt:control-plane-protocol"+
           "/isis:isis/isis:overload" {
       when "rt:type = 'isis:isis'" {
         description
         "This augment IS-IS routing protocol when used";
       }
       description
        "This augments IS-IS overload configuration
         with per level configuration.";

       container level-1 {
           uses isis:overload-global-cfg;
           description
            "Level 1 configuration.";
       }
       container level-2 {
           uses isis:overload-global-cfg;
           description
            "Level 2 configuration.";
       }

   }

   If an implementation does not support per level configuration for a
   parameter modeled with per level configuration, the implementation
   SHOULD advertise a deviation to announce the non support of the
   level-1 and level-2 containers.

   Finally, if an implementation supports per level configuration but
   does not support the level-1-2 configuration, it SHOULD also
   advertise a deviation.

2.4.  Per-Interface Parameters

   The per-interface section of the IS-IS instance describes the
   interface specific parameters.

   The interface is modeled as a reference to an existing interface
   defined in the "ietf-interfaces" YANG model.

   Each interface has some interface-specific parameters that may have a
   different per level value as described in previous section.  An
   interface-specific parameter always override an IS-IS global
   parameter.

   Some parameters like hello-padding are defined as containers to allow
   easy extension by vendor specific modules.

      +--rw interfaces
         +--rw interface* [name]
            +--rw name                       if:interface-ref
            +--rw level-type?                level
            +--rw lsp-pacing-interval?       uint16       rt-types:timer-value-millis
econds
            +--rw lsp-retransmit-interval?   uint16   rt-types:timer-value-second
s16
            +--rw passive?                   boolean
            +--rw csnp-interval?             uint16             rt-types:timer-value-second
s16
            +--rw hello-padding
            |  +--rw enable?   boolean
            +--rw mesh-group-enable?         mesh-group-state
            +--rw mesh-group?                uint8
            +--rw interface-type?            interface-type
            +--rw enable?                    boolean {admin-control}?
            +--rw tag*                       uint32 {prefix-tag}?
            +--rw tag64*                     uint64 {prefix-tag64}?
            +--rw node-flag?                 boolean {node-flag}?
            +--rw hello-authentication
            |  +--rw (authentication-type)?
            |  |  +--:(key-chain) {key-chain}?
            |  |  |  +--rw key-chain?          key-chain:key-chain-ref
            |  |  +--:(password)
            |  |     +--rw key?                string
            |  |     +--rw crypto-algorithm?   identityref
            |  +--rw level-1
            |  |  +--rw (authentication-type)?
            |  |     +--:(key-chain) {key-chain}?
            |  |     |  +--rw key-chain?          key-chain:key-chain-re
f
            |  |     +--:(password)
            |  |        +--rw key?                string
            |  |        +--rw crypto-algorithm?   identityref
            |  +--rw level-2
            |     +--rw (authentication-type)?
            |        +--:(key-chain) {key-chain}?
            |        |  +--rw key-chain?          key-chain:key-chain-re
f
            |        +--:(password)
            |           +--rw key?                string
            |           +--rw crypto-algorithm?   identityref
            +--rw hello-interval
            |  +--rw value?     uint16     rt-types:timer-value-seconds16
            |  +--rw level-1
            |  |  +--rw value?   uint16   rt-types:timer-value-seconds16
            |  +--rw level-2
            |     +--rw value?   uint16   rt-types:timer-value-seconds16
            +--rw hello-multiplier
            |  +--rw value?     uint16
            |  +--rw level-1
            |  |  +--rw value?   uint16
            |  +--rw level-2
            |     +--rw value?   uint16
            +--rw priority
            |  +--rw value?     uint8
            |  +--rw level-1
            |  |  +--rw value?   uint8
            |  +--rw level-2
            |     +--rw value?   uint8
            +--rw metric
            |  +--rw value?     wide-metric
            |  +--rw level-1
            |  |  +--rw value?   wide-metric
            |  +--rw level-2
            |     +--rw value?   wide-metric
            +--rw bfd {bfd}?
            |  +--rw enable?   boolean
            +--rw afs {nlpid-control}?
            |  +--rw af* [af]
            |     +--rw af    identityref
            +--rw mpls
            |  +--rw ldp
            |     +--rw igp-sync?   boolean {ldp-igp-sync}?
            +--rw fast-reroute {fast-reroute}?
            |  +--rw lfa {lfa}?
            |     +--rw candidate-disabled?   boolean
            |     +--rw enable?               boolean
            |     +--rw remote-lfa {remote-lfa}?
            |     |  +--rw enable?   boolean
            |     +--rw level-1
            |     |  +--rw candidate-disabled?   boolean
            |     |  +--rw enable?               boolean
            |     |  +--rw remote-lfa {remote-lfa}?
            |     |     +--rw enable?   boolean
            |     +--rw level-2
            |        +--rw candidate-disabled?   boolean
            |        +--rw enable?               boolean
            |        +--rw remote-lfa {remote-lfa}?
            |           +--rw enable?   boolean
            +--rw topologies {multi-topology}?
               +--rw topology* [name]
                  +--rw name      leafref
                  +--rw metric
                     +--rw value?     wide-metric
                     +--rw level-1
                     |  +--rw value?   wide-metric
                     +--rw level-2
                        +--rw value?   wide-metric

2.5.  Authentication Parameters

   The module enables authentication configuration through the IETF key-
   chain module ([I-D.ietf-rtgwg-yang-key-chain]).  The IS-IS module
   imports the "ietf-key-chain" module and reuses some groupings to
   allow global and per interface configuration of authentication.  If a
   global authentication is configured, an implementation SHOULD
   authenticate PSNPs, CSNPs and LSPs with the authentication parameters
   supplied.  The authentication of hello PDUs can be activated on a per
   interface basis.

2.6.  IGP/LDP synchronization

   [RFC5443] defines a mechanism where IGP needs to be synchronized with
   LDP.  An "ldp-igp-sync" feature has been defined in the model to
   support this mechanism.  The "mpls/ldp/igp-sync" leaf under
   "interface" allows activation of the mechanism on a per interface
   basis.  The "mpls/ldp/igp-sync" container in the global configuration
   is empty on purpose and is not required for the activation.  The goal
   of this empty container is to allow easy augmentation with additional
   parameters like timers for example.

2.7.  ISO parameters

   As IS-IS protocol is based on ISO protocol suite, some ISO parameters
   may be required.

   This module augments interface configuration model to support ISO
   configuration parameters.

   The clns-mtu can be defined under the interface.

2.8.  IP FRR

   This YANG model supports LFA ([RFC5286]) and remote LFA ([RFC7490])
   as IP FRR techniques.  The "fast-reroute" container may be augmented
   by other models to support other IPFRR flavors (MRT, TILFA ...).

   The current version of the model supports activation of LFA and
   remote LFA at interface only.  The global "lfa" container is present
   but kept empty to allow augmentation with vendor specific properties
   like policies.

   Remote LFA is considered as a child of LFA.  Remote LFA cannot be
   enabled if LFA is not enabled.

   The "candidate-disabled" allows to mark an interface to not be used
   as a backup.

2.9.  Operational States

   An "isis" container provides operational states for IS-IS.  This
   container is divided in multiple components:

   o  system-counters : provides statistical informations about the
      global system.

   o  interface : provides configuration state informations for each
      interface.

   o  adjacencies: provides state informations about current IS-IS
      adjacencies.

   o  spf-log: provides informations about SPF events on the node.  This
      SHOULD be implemented as a wrapping buffer.

   o  lsp-log: provides informations about LSP events on the node
      (reception of an LSP or modification of local LSP).  This SHOULD
      be implemented as a wrapping buffer and an implementation MAY
      decide to log refresh LSPs or not.

   o  local-rib: provides the IS-IS internal routing table view.

   o  database: provides details on the current LSDB.

   o  hostnames: provides informations about system-id to hostname
      mappings.

   o  fast-reroute: provides informations about IP FRR.

3.  RPC Operations

   The "ietf-isis" module defines two RPC operations:

   o  clear-isis-database: reset the content of a particular IS-IS
      database and restart database synchronization with the neighbors.

   o  clear-isis-adjacency: restart a particular set of IS-IS
      adjacencies.

   rpcs:
      +---x clear-adjacency
      |  +--ro input
      |     +--ro routing-protocol-instance-name    instance-state-ref
      |     +--ro level?                            level
      |     +--ro interface?                        string
      +---x clear-database
         +--ro input
            +--ro routing-protocol-instance-name    instance-state-ref
            +--ro level?                            level

4.  Notifications

   The "ietf-isis" module introduces some notifications :

      database-overload : raised when overload condition is changed.

      lsp-too-large : raised when the system tries to propagate a too
      large PDU.

      corrupted-lsp-detected : raised when the system find that an LSP
      that was stored in memory has become corrupted.

      attempt-to-exceed-max-sequence : This notification is sent when
      the system wraps the 32-bit sequence counter of an LSP.

      id-len-mismatch : This notification is sent when we receive a PDU
      with a different value for the System ID length.

      max-area-addresses-mismatch : This notification is sent when we
      receive a PDU with a different value for the Maximum Area
      Addresses.

      own-lsp-purge : This notification is sent when the system receives
      a PDU with its own system ID and zero age.

      sequence-number-skipped : This notification is sent when the
      system receives a PDU with its own system ID and different
      contents.  The system has to reissue the LSP with a higher
      sequence number.

      authentication-type-failure : This notification is sent when the
      system receives a PDU with the wrong authentication type field.

      authentication-failure : This notification is sent when the system
      receives a PDU with the wrong authentication information.

      version-skew : This notification is sent when the system receives
      a PDU with a different protocol version number.

      area-mismatch : This notification is sent when the system receives
      a Hello PDU from an IS that does not share any area address.

      rejected-adjacency : This notification is sent when the system
      receives a Hello PDU from an IS but does not establish an
      adjacency for some reason.

      protocols-supported-mismatch : This notification is sent when the
      system receives a non pseudonode LSP that has no matching protocol
      supported.

      lsp-error-detected : This notification is sent when the system
      receives a LSP with a parse error.

      adjacency-change : This notification is sent when an IS-IS
      adjacency moves to Up state or to Down state.

      lsp-received : This notification is sent when a LSP is received.

      lsp-generation : This notification is sent when a LSP is
      regenerated.

   notifications:
      +---n database-overload
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro overload?                enumeration
      +---n lsp-too-large
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro pdu-size?                uint32
      |  +--ro lsp-id?                  lsp-id
      +---n if-state-change
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro state?                   if-state-type
      +---n corrupted-lsp-detected
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro lsp-id?                  lsp-id
      +---n attempt-to-exceed-max-sequence
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro lsp-id?                  lsp-id
      +---n id-len-mismatch
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro pdu-field-len?           uint8
      |  +--ro raw-pdu?                 binary
      +---n max-area-addresses-mismatch
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro max-area-addresses?      uint8
      |  +--ro raw-pdu?                 binary
      +---n own-lsp-purge
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro lsp-id?                  lsp-id
      +---n sequence-number-skipped
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro lsp-id?                  lsp-id
      +---n authentication-type-failure
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro raw-pdu?                 binary
      +---n authentication-failure
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro raw-pdu?                 binary
      +---n version-skew
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro protocol-version?        uint8
      |  +--ro raw-pdu?                 binary
      +---n area-mismatch
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro raw-pdu?                 binary
      +---n rejected-adjacency
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro raw-pdu?                 binary
      |  +--ro reason?                  string
      +---n protocols-supported-mismatch
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro raw-pdu?                 binary
      |  +--ro protocols*               uint8
      +---n lsp-error-detected
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro lsp-id?                  lsp-id
      |  +--ro raw-pdu?                 binary
      |  +--ro error-offset?            uint32
      |  +--ro tlv-type?                uint8
      +---n adjacency-state-change
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro neighbor?                string
      |  +--ro neighbor-system-id?      system-id
      |  +--ro state?                   adj-state-type
      |  +--ro reason?                  string
      +---n lsp-received
      |  +--ro routing-instance?        string
      |  +--ro routing-protocol-name?   string
      |  +--ro isis-level?              level
      |  +--ro interface-name?          string
      |  +--ro interface-level?         level
      |  +--ro extended-circuit-id?     extended-circuit-id
      |  +--ro lsp-id?                  lsp-id
      |  +--ro sequence?                uint32
      |  +--ro received-timestamp?      yang:timestamp
      |  +--ro neighbor-system-id?      system-id
      +---n lsp-generation
         +--ro routing-instance?        string
         +--ro routing-protocol-name?   string
         +--ro isis-level?              level
         +--ro lsp-id?                  lsp-id
         +--ro sequence?                uint32
         +--ro send-timestamp?          yang:timestamp

5.  Interaction with Other YANG Modules

   The "isis" configuration container augments the "/rt:routing/
   rt:control-plane-protocols/control-plane-protocol" container of the
   ietf-routing [I-D.ietf-netmod-routing-cfg] module by defining IS-IS
   specific parameters.

   The "isis" module augments "/if:interfaces/if:interface" with ISO
   specific parameters.

   The "isis" operational state container augments the "/rt:routing-
   state/rt:control-plane-protocols/control-plane-protocol" container of
   the ietf-routing module by defining IS-IS specific operational
   states.

   Some IS-IS specific routes attributes are added to route objects of
   the ietf-routing module by augmenting "/rt:routing-
   state/rt:ribs/rt:rib/rt:routes/rt:route".

   The modules defined in this document use some groupings from ietf-
   keychain [I-D.ietf-rtgwg-yang-key-chain].

6.  IS-IS YANG Module

  <CODE BEGINS> file "ietf-isis@2017-03-29.yang" "ietf-isis@2017-03-30.yang"

  module ietf-isis {
    namespace "urn:ietf:params:xml:ns:yang:ietf-isis";

    prefix isis;

    import ietf-routing {
      prefix "rt";
    }

    import ietf-inet-types {
      prefix inet;
    }

    import ietf-yang-types {
      prefix yang;
    }

    import ietf-interfaces {
      prefix "if";
    }

    import ietf-key-chain {
      prefix "key-chain";
    }

    import ietf-routing-types {
      prefix "rt-types";
    }
    organization
     "IETF ISIS Working Group";

    contact
      "WG List:  &lt;mailto:isis-wg@ietf.org&gt;

      Editor:    Stephane Litkowski
            &lt;mailto:stephane.litkowski@orange.com&gt;

          Derek Yeung
            &lt;mailto:derek@arrcus.com&gt;
          Acee Lindem
            &lt;mailto:acee@cisco.com&gt;
          Jeffrey Zhang
            &lt;mailto:zzhang@juniper.net&gt;
          Ladislav Lhotka
            &lt;mailto:llhotka@nic.cz&gt;
          Yi Yang
            &lt;mailto:yiya@cisco.com&gt;
          Dean Bogdanovic
            &lt;mailto:deanb@juniper.net&gt;
          Kiran Agrahara Sreenivasa
            &lt;mailto:kkoushik@brocade.com&gt;
          Yingzhen Qu
            &lt;mailto:yiqu@cisco.com&gt;
          Jeff Tantsura
            &lt;mailto:jefftant.ietf@gmail.com&gt;

      ";

    description
      "The YANG module defines a generic configuration model for
      ISIS common across all of the vendor implementations.";

    revision 2017-03-29 2017-03-30 {
      description
       "Initial revision.";
       reference "RFC XXXX";
    }

   /* Identities */

    identity isis {
      base rt:routing-protocol;
      description "Identity for the ISIS routing protocol.";
    }

    identity isis-adjacency-change {
      description "Identity for the ISIS routing protocol
        adjacency state.";
    }

    identity clear-isis-database {
      description "Identity for the ISIS routing protocol
        database reset action.";
    }

    identity clear-isis-adjacency {
      description "Identity for the ISIS routing protocol
        adjacency reset action.";
    }

    identity lsp-log-reason {
      description "Base identity for an LSP change
              log reason.";
    }

    identity refresh {
      base lsp-log-reason;
      description
       "Identity used when the LSP log reason is
       a refresh LSP received.";
    }

    identity content-change {
      base lsp-log-reason;
      description
       "Identity used when the LSP log reason is
       a change in the content of the LSP.";
    }

    /* Feature definitions */

    feature ietf-spf-delay {
      description
       "Support of IETF SPF delay algorithm.";
    }
    feature bfd {
      description
       "Support of BFD for IS-IS links.";
    }
    feature key-chain {
      description
        "Support of keychain for authentication.";
    }
    feature segment-routing {
      description
       "Support of segment-routing.";
    }
    feature node-flag {
      description
       "Support of node-flag advertisement
       as prefix attribute";
    }
    feature node-tag {
      description
        "Support of node tag.";
    }
    feature ldp-igp-sync {
      description
        "Support of RFC5443.";
    }
    feature fast-reroute {
      description
        "Support of IPFRR.";
    }
    feature nsr {
      description
       "Support of
          Non Stop Routing.";
    }
    feature  lfa {
      description
        "Support of Loop Free Alternates.";
    }
    feature remote-lfa {
      description
        "Support of remote Loop Free Alternates.";
    }

    feature overload-max-metric {
      description
        "Support of overload by setting
         all links to max metric.";
    }
    feature prefix-tag {
      description
        "Add 32bit tag to prefixes";
    }
    feature prefix-tag64 {
      description
        "Add 64bit tag to prefixes";
    }
    feature auto-cost {
      description
        "Use an automated assignment of metrics.";
    }
    feature ipv4-router-id {
      description
       "Support of IPv4 router ID configuration under ISIS.";
    }

    feature ipv6-router-id {
      description
       "Support of IPv6 router ID configuration under ISIS.";
    }

    feature multi-topology {
      description
       "Multitopology routing support.";
    }
    feature nlpid-control {
      description
       "This feature controls the advertisement
        of support NLPID within ISIS configuration.";
    }
    feature graceful-restart {
      description
        "Graceful restart support as per RFC5306.";
    }

    feature lsp-refresh {
      description
        "Configuration of LSP refresh interval.";
    }

    feature maximum-area-addresses {
      description
        "Support of maximum-area-addresses config.";
    }

    feature admin-control {
      description
       "Control administrative state of ISIS.";
    }

    /* Type definitions */

    typedef instance-state-ref {
      type leafref {
        path "/rt:routing-state/"
        +"rt:control-plane-protocols/rt:control-plane-protocol/"
        +"rt:name";
      }
      description
         "This type is used for leaves that reference state data of
          an ISIS protocol instance.";
    }

    typedef admin-state {
      type enumeration {
        enum "up" {
          description
           "Up state";
        }
        enum "down" {
          description
           "Down state";
        }
      }
      description
       "Administrative state of a component.";
    }
    typedef oper-state {
      type enumeration {
        enum "up" {
          description
           "Up state";
        }
        enum "down" {
          description
           "Down state";
        }
      }
      description
       "Operational state of a component.";
    }
    typedef circuit-id {
      type uint8;
      description
       "This type defines the circuit ID
       associated with an interface.";
    }

    typedef extended-circuit-id {
      type uint32;
      description
       "This type defines the extended circuit ID
       associated with an interface.";
    }

    typedef interface-type {
      type enumeration {
        enum broadcast {
          description
          "Broadcast interface type.
          Would result in DIS election."; type.";
        }
        enum point-to-point {
          description
           "Point to point interface type.";
        }
      }
      description
       "This type defines the type of adjacency
       to be established on the interface.
       This is affecting the type of hello
       message that would be used.";

    }

    typedef level {
      type enumeration {
        enum "level-1" {
          description
           "This enum describes L1 only capability.";
        }
        enum "level-2" {
          description
           "This enum describes L2 only capability.";
        }
        enum "level-all" {
          description
           "This enum describes both levels capability.";
        }
      }
      default "level-all";
      description
       "This type defines ISIS level of an object.";

    }

    typedef adj-state-type {
       type enumeration {
          enum "Up" {
            description
             "This state describes that
              adjacency is established.";
          }
          enum "Down" {
            description
             "This state describes that
              adjacency is NOT established.";
          }
          enum "Init" {
            description
             "This state describes that
              adjacency is establishing.";
          }
          enum "Failed" {
            description
             "This state describes that
              adjacency is failed.";
          }
        }
        description
        "This type defines states of an adjacency";
    }

    typedef if-state-type {
       type enumeration {
          enum "Up" {
            description
             "This state describes that
              .";
             "Up state.";

          }
          enum "Down" {
            description
             "This state describes that
              .";
             "Down state";
          }
        }
        description
        "This type defines states of an interface";
    }

    typedef level-number {
      type uint8 {
        range "1 .. 2";
      }
      description
       "This type defines a current ISIS level.";
    }

    typedef lsp-id {
      type string {
        pattern
         '[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]'
               +'{4}\.[0-9][0-9]-[0-9][0-9]';
      }
      description
       "This type defines ISIS LSP ID using pattern,
        system id looks like : 0143.0438.AeF0.02-01";
    }

    typedef area-address {
      type string {
        pattern '[0-9A-Fa-f]{2}\.([0-9A-Fa-f]{4}\.){0,3}';
      }
      description
       "This type defines the area address."; address format.";
    }

    typedef snpa {
      type string {
        length "0 .. 20";
      }
      description
       "This type defines Subnetwork Point
        of Attachement format.";
    }

    typedef system-id {
      type string {
        pattern
         '[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}\.[0-9A-Fa-f]{4}';
      }
      description
       "This type defines ISIS system id using pattern,
        system id looks like : 0143.0438.AeF0";
    }

    typedef wide-metric {
      type uint32 {
        range "0 .. 16777215";
      }
      description
       "This type defines wide style format
        of ISIS metric.";
    }

    typedef std-metric {
      type uint8 {
        range "0 .. 63";
      }
      description
       "This type defines old style format
        of ISIS metric.";
    }

    typedef mesh-group-state {
      type enumeration {
        enum "meshInactive" {
          description
           "Interface is not part of a mesh group.";
        }
        enum "meshSet" {
          description
           "Interface is part of a mesh group.";
        }
        enum "meshBlocked" {
          description
           "LSPs must not be flooded over that interface.";
        }
      }
      description
       "This type describes meshgroup state of an interface";
    }

    /* Grouping definitions for configuration and ops state */
    grouping local-rib {
      description "Local-rib grouping.";
      container local-rib {
        description "Local-rib.";
        list route {
          key "prefix";
          description "Routes";
          leaf prefix {
            type inet:ip-prefix;
            description "Destination prefix.";
          }
          container next-hops {
            description "All next hops for the route.";
            list next-hop {
              key "next-hop";
              description "List of next hop for the route";
              leaf outgoing-interface {
                type if:interface-ref;
                description
                  "Name of the outgoing interface.";
              }
              leaf next-hop {
               type inet:ip-address;
               description "Nexthop address.";
              }
            }
          }
          leaf metric {
            type uint32;
            description "Metric for this route.";
          }
          leaf level {
            type level-number;
            description "Level number for this route.";
          }
          leaf route-tag {
            type uint32;
            description "Route tag for this route.";
          }
        }
      }
    }

   grouping admin-control {
      leaf enable {
          if-feature admin-control;
          type boolean;
          default true;
          description
               "Control the administrative
               state.";
      }
      description
       "Grouping for admin control.";
    }

   grouping adjacency-state adjacency-state {
     container adjacencies {
        list adjacency {
          leaf neighbor-systype {
            type level;
            description
             "Type of neighboring system";
          }
          leaf neighbor-sysid {
            type system-id;
            description
             "The system-id of the neighbor";
          }
          leaf neighbor-extended-circuit-id {
            type extended-circuit-id;
            description
             "Circuit ID of the neighbor";
          }
          leaf neighbor-snpa {
            type snpa;
            description
             "SNPA of the neighbor";
          }
          leaf usage {
            type level;
            description
            "How is the adjacency used ?
            On a p2p link this might be level 1 and 2,
            but on a LAN, the usage will be level 1
            between peers at L1 or level 2 between
            peers at L2.";
          }
          leaf hold-timer {
            type uint16; rt-types:timer-value-seconds16;
            units seconds;
            description
             "The holding time in seconds for this
              adjacency. This value is based on
              received hello PDUs and the elapsed
              time since receipt.";
          }
          leaf neighbor-priority {
            type uint8 {
              range "0 .. 127";
            }
            description
             "Priority of the neighboring IS for becoming
              the DIS.";

          }
          leaf lastuptime {
            type yang:timestamp;
            description
             "When the adjacency most recently entered
              state 'up', measured in hundredths of a
              second since the last reinitialization of
              the network management subsystem.
              The value is 0 if the adjacency has never
              been in state 'up'.";
          }
          leaf state {
            type adj-state-type;
            description
             "This leaf describes the state of the
             interface.";
          }

          description
           "List of operational adjacencies.";
        }
        description
         "This container lists the adjacencies of
         the local node.";
      }
      description
       "Adjacency state";
    }

    grouping fast-reroute-global-state {
        container protected-routes {
          list af-stats {
            key "af prefix alternate";

            leaf af {
              type identityref {
                base rt:address-family; rt-types:address-family;
              }
              description
               "Address-family";
            }
            leaf prefix {
              type string;
              description
               "Protected prefix.";
            }
            leaf alternate {
              type string;
              description
               "Alternate nexthop for the prefix.";
            }
            leaf alternate-type {
              type enumeration {
                enum equalcost {
                  description
                   "ECMP alternate.";
                }
                enum lfa {
                  description
                   "LFA alternate.";
                }
                enum remote-lfa {
                  description
                   "Remote LFA alternate.";
                }
                enum tunnel {
                  description
                   "Tunnel based alternate
                   (like RSVP-TE or GRE).";
                }
                enum ti-lfa {
                  description
                   "TI LFA alternate.";
                }
                enum mrt {
                  description
                   "MRT alternate.";
                }
                enum other {
                  description
                   "Unknown alternate type.";
                }
              }
              description
               "Type of alternate.";
            }
            leaf best {
              type boolean;
              description
               "describes if the alternate is the best one.";
            }
            leaf non-best-reason {
              type string;
              description
               "Information field to describe why the alternate
               is not best.";

            }
            leaf protection-available {
              type bits {
                bit nodeprotect {
                  position 0;
                  description
                  "Node protection available.";
                }
                bit linkprotect {
                  position 1;
                  description
                  "Link protection available.";
                }
                bit srlgprotect {
                  position 2;
                  description
                  "SRLG protection available.";
                }
                bit downstreamprotect {
                  position 3;
                  description
                  "Downstream protection available.";
                }
                bit other {
                  position 4;
                  description
                  "Other protection available.";
                }
              }
              description
              "Describes protection provided by the alternate.";
            }
            leaf alternate-metric1 {
              type uint32;
              description
               "Metric from PLR to destination
                through the alternate path.";
            }
            leaf alternate-metric2 {
              type uint32;
              description
               "Metric from PLR to the alternate node";
            }
            leaf alternate-metric3 {
              type uint32;
              description
               "Metric from alternate node to the destination";
            }
            description
             "Per AF statistics.";
          }
          description
           "List of prefixes that are protected.";
        }

        container nonprotected-routes {
           list af-stats {
            key "af prefix";

            leaf af {
              type identityref {
                base rt:address-family; rt-types:address-family;
              }
              description
               "Address-family";
            }
            leaf prefix {
              type string;
              description
               "Protected prefix.";
            }
            description
             "Per AF statistics.";
          }
          description
           "List of prefixes that are not protected.";
        }

        list protection-statistics {
          key frr-protection-method;

          leaf frr-protection-method {
            type string;
            description
             "Protection method used.";
          }
          list af-stats {
            key af;

            leaf af {
              type identityref {
                base rt:address-family; rt-types:address-family;
              }
              description
               "Address-family";
            }
            leaf total-routes {
              type uint32;
              description
               "Total prefixes.";
            }
            leaf unprotected-routes {
              type uint32;
              description
                "Total of prefixes who are
                not protected.";
            }
            leaf protected-routes {
              type uint32;
              description
                "Total of prefixes who are
                protected.";
            }
            leaf linkprotected-routes {
              type uint32;
              description
                "Total of prefixes who are
                link protected.";
            }
            leaf nodeprotected-routes {
              type uint32;
              description
                "Total of prefixes who are
                node protected.";
            }
            description
             "Per AF statistics.";
          }

          description
           "Global protection statistics.";
        }
        description
         "IPFRR states.";
    }

    grouping notification-instance-hdr {
      description
       "This group describes common instance specific
        data for notifications.";
      leaf routing-instance {
        type string;
        description
         "Describes the name of the routing-instance instance.";

      }
      leaf routing-protocol-name {
        type string;
        description
         "Describes the name of the ISIS instance.";
      }
      leaf isis-level {
        type level;
        description
         "Describes the ISIS level of the instance.";
      }
    }

    grouping notification-interface-hdr {
      description
       "This group describes common interface specific
        data for notifications.";
      leaf interface-name {
        type string;
        description
         "Describes the name of the ISIS interface.";
      }
      leaf interface-level {
        type level;
        description
         "Describes the ISIS level of the interface.";
      }
      leaf extended-circuit-id {
        type extended-circuit-id;
        description
         "Describes the extended circuit-id of the interface.";
      }
    }

    grouping route-content {
      description
       "This group add isis-specific route properties.";
      leaf metric {
        type uint32;
        description
         "This leaf describes ISIS metric of a route.";
      }
      leaf-list tag {
        type uint64;
        description
         "This leaf describes list of tags associated
          with the route. The leaf describes both
          32bits and 64bits tags.";

      }
      leaf route-type {
        type enumeration {
          enum l2-up-internal {
            description "Level 2 internal route
             and not leaked to a lower level";
          }
          enum l1-up-internal {
            description "Level 1 internal route
             and not leaked to a lower level";
          }
          enum l2-up-external {
            description "Level 2 external route
             and not leaked to a lower level";
          }
          enum l1-up-external {
            description "Level 1 external route
             and not leaked to a lower level";
          }
          enum l2-down-internal {
            description "Level 2 internal route
             and leaked to a lower level";
          }
          enum l1-down-internal {
            description "Level 1 internal route
             and leaked to a lower level";
          }
          enum l2-down-external {
            description "Level 2 external route
             and leaked to a lower level";
          }
          enum l1-down-external {
            description "Level 1 external route
             and leaked to a lower level";
          }
        }
        description
         "This leaf describes the type of ISIS route.";
      }
    }

    grouping admin-control {
      leaf enable {
          if-feature admin-control;
          type boolean;
          default true;
          description
               "Control the administrative
               state.";
      }
      description
       "Grouping for admin control.";
    }

    grouping fast-reroute-global-cfg {
      description
       "This group defines global
       configuration of IPFRR.";
      container lfa {
        if-feature lfa;
        description
          "This container may be
          augmented with global parameters
          for LFA.
          Creating the container has no effect on
          LFA activation.";
      }
    }

    grouping fast-reroute-if-cfg {
      description
       "This group defines interface
       configuration of IPFRR.";
        container lfa {
          if-feature lfa;
          uses lfa-if-cfg;
          container level-1 {
              uses lfa-if-cfg;
              description
               "LFA level 21 1 config";
          }
          container level-2 {
              uses lfa-if-cfg;
              description
               "LFA level 2 config";
          }
          description
              "LFA config";
        }
    }

    grouping ietf-spf-delay-cfg {
      leaf initial-delay {
          type uint16; rt-types:timer-value-milliseconds;
          units msec;
          description
           "Delay used while in QUIET state.";
      }
      leaf short-delay {
          type uint16; rt-types:timer-value-milliseconds;
          units msec;
          description
           "Delay used while in SHORT_WAIT state.";
      }
      leaf long-delay {
          type uint16; rt-types:timer-value-milliseconds;
          units msec;
          description
           "Delay used while in LONG_WAIT state.";
      }

      leaf hold-down {
          type uint16; rt-types:timer-value-milliseconds;
          units msec;
          description
           "Timer used to consider an IGP stability period.";
      }
      leaf time-to-learn {
          type uint16; rt-types:timer-value-milliseconds;
          units msec;
          description
           "Duration used to learn all the IGP events
           related to a single component failure.";
      }

      description
       "Grouping for IETF SPF delay configuration.";
    }

    grouping ietf-spf-delay-state {
      leaf current-state {
          type enumeration {
              enum "QUIET" {
                  description "QUIET state";
              }
              enum "SHORT_WAIT" {
                  description "SHORT_WAIT state";
              }
              enum "LONG_WAIT" {
                  description "LONG_WAIT state";
              }
          }
          description
           "Current state of the algorithm.";

      }
      leaf remaining-time-to-learn {
          type uint16; rt-types:timer-value-milliseconds;
          units "seconds"; "msec";
          description
           "Remaining time until time-to-learn timer fires.";
      }
      leaf remaining-hold-down {
          type uint16; rt-types:timer-value-milliseconds;
          units "seconds"; "msec";
          description
           "Remaining time until hold-down timer fires.";
      }
      leaf last-event-received {
          type yang:timestamp;
          description
           "Time of last IGP event received";
      }
      leaf next-spf-time {
          type yang:timestamp;
          description
           "Time when next SPF has been scheduled.";
      }
      leaf last-spf-time {
          type yang:timestamp;
          description
           "Time of last SPF computation.";
      }
      description
       "Grouping for IETF SPF delay operational states.";
    }

     grouping prefix-reachability-attributes local-rib {
      description
       "This group defines extended reachability attributes of an
        IPv4 or IPv6 prefix."; "Local-rib grouping.";
      container local-rib {
        description "Local-rib.";
        list route {
          key "prefix";
          description "Routes";
          leaf external-prefix-flag prefix {
            type boolean; inet:ip-prefix;
            description
           "External prefix flag."; "Destination prefix.";
          }
          container next-hops {
            description "All next hops for the route.";
            list next-hop {
              key "next-hop";
              description "List of next hop for the route";
              leaf readvertisement-flag outgoing-interface {
                type boolean; if:interface-ref;
                description
           "Readvertisement flag.";
                  "Name of the outgoing interface.";
              }
              leaf node-flag next-hop {
               type boolean; inet:ip-address;
               description
           "Node flag."; "Nexthop address.";
              }
            }

    grouping prefix-ipv4-source-router-id
          }
          leaf metric {
            type uint32;
            description
       "This group defines the IPv4 source router ID of
       a prefix advertisement."; "Metric for this route.";
          }
          leaf ipv4-source-router-id level {
            type inet:ipv4-address; level-number;
            description
           "IPv4 Source router ID address.";
      } "Level number for this route.";
          }
    grouping prefix-ipv6-source-router-id {
      description
       "This group defines the IPv6 source router ID of
       a prefix advertisement.";
          leaf ipv6-source-router-id route-tag {
            type inet:ipv6-address; uint32;
            description
           "IPv6 Source router ID address."; "Route tag for this route.";
          }
        }
      }

    grouping prefix-attributes-extension {
      description
       "Prefix extended attributes.";

      uses prefix-reachability-attributes;
      uses prefix-ipv4-source-router-id;
      uses prefix-ipv6-source-router-id;
    }

    grouping prefix-ipv4-std isis-node-tag-cfg {
      description
       "This group defines attributes of an
        IPv4 standard prefix.";
       "ISIS node tag config.";
      container node-tags {
          if-feature node-tag;
          list node-tag {
            key tag;
            leaf up-down tag {
              type boolean; uint32;
              description
         "This leaf expresses the value
               "Node tag value.";
            }
            description
             "List of up/down bit."; tags.";
          }
          description
            "Container for node tags.";
        }
    }

    grouping authentication-global-cfg {
      choice authentication-type {
          case key-chain {
            if-feature key-chain;
            leaf i-e key-chain {
              type boolean; key-chain:key-chain-ref;
              description
         "This leaf expresses the value of I/E bit.";
                "Reference to a key-chain.";
            }
          }
          case password {
            leaf ip-prefix key {
              type inet:ipv4-address; string;
              description
               "This leaf describes the IPv4 prefix";
                 authentication key.";
            }
            leaf prefix-len crypto-algorithm {
              type uint8; identityref {
                  base key-chain:crypto-algorithm;
              }
              description
         "This leaf describes the IPv4 prefix len in bits";
                "Cryptographic algorithm associated with key.";
            }
          }
          description
             "Choice of authentication.";
        }
       description
        "Grouping for global auth config.";
    }

    grouping metric-type-global-cfg {
      leaf default-metric value {
          type std-metric; enumeration {
            enum wide-only {
              description
         "This leaf describes the ISIS default
               "Advertise new metric value"; style only
               (RFC5305)";
            }
      container delay-metric
            enum old-only {
        leaf
              description
               "Advertise old metric style only
               (RFC1195)";
            }
            enum both {
          type std-metric;
              description
           "This leaf describes the ISIS delay "Advertise both metric value";
              styles";
            }

          }
        leaf supported {
          type boolean;
          default "false";
          description
           "This leaf describes if the type of metric
           to be generated.
           Wide-only means only new metric style
           is supported."; generated,
           old-only means that only old style metric
           is generated,
           and both means that both are advertised.
           This leaf is only affecting IPv4 metrics.";
        }
         description
         "This container defines the ISIS delay metric.";
        "Grouping for global metric style config.";
    }
      container expense-metric

    grouping default-metric-global-cfg {
      leaf metric value {
          type std-metric; wide-metric;
          default "10";
          description
           "This leaf describes
            "Value of the ISIS expense metric";
      }
      description
            "Grouping for global default metric value"; config.";
    }

    grouping overload-global-cfg {
      leaf supported status {
          type boolean;
          default "false";
          description
           "This leaf describes if defines the metric is supported."; overload status.";
      }
            description
        "Grouping for overload bit config.";
    }

    grouping overload-max-metric-global-cfg {
      leaf timeout {
          type rt-types:timer-value-seconds16;
          units "seconds";
          description
           "This container leaf defines the ISIS expense metric."; timeout in seconds
            of the overload condition.";
        }
      container error-metric
        description
        "Grouping for overload-max-metric config.";
    }
    grouping route-preference-global-cfg {
      choice granularity {
              case detail {
                leaf metric internal {
                  type std-metric; uint8;
                  description
                    "This leaf describes defines the ISIS error metric value"; protocol
                     preference for internal routes.";
                }
                leaf supported external {
                  type boolean;
          default "false"; uint8;
                  description
                    "This leaf describes if defines the metric is supported."; protocol
                     preference for external routes.";
                }
              }
              case coarse {
                leaf default {
                  type uint8;
                  description
                    "This container leaf defines the protocol
                     preference for all ISIS error metric."; routes.";
                }
              }

    grouping prefix-ipv4-extended {
              description
               "Choice for implementation of route preference.";
            }
      description
       "This group grouping defines attributes of an
        IPv4 extended prefix."; how route preference is configured.";
    }

    grouping hello-authentication-cfg {
      choice authentication-type {
          case key-chain {
            if-feature key-chain;
            leaf up-down key-chain {
              type boolean; key-chain:key-chain-ref;
              description
         "This leaf expresses the value of up/down bit.";
                "Reference to a key-chain.";
            }
          }
          case password {
            leaf ip-prefix key {
              type inet:ipv4-address; string;
              description
               "This leaf describes the IPv4 prefix";
                 authentication key.";
            }
            leaf prefix-len crypto-algorithm {
              type uint8; identityref {
                  base key-chain:crypto-algorithm;
              }
              description
         "This leaf describes the IPv4 prefix len in bits";
      }

      leaf metric {
        type wide-metric;
        description
         "This leaf describes the ISIS metric value";
      }
      leaf-list tag {
        type uint32;
        description
         "This leaf describes a list of tags
                "Cryptographic algorithm associated with
         the prefix."; key.";
            }
          }
      leaf-list tag64 {
        type uint64;
          description
         "This leaf describes a list
             "Choice of 64-bit tags associated with
         the prefix."; authentication.";
        }

      uses prefix-attributes-extension;
        description
         "Grouping for hello authentication.";
    }

    grouping prefix-ipv6-extended hello-interval-cfg {
      description
       "This group defines attributes of an
        IPv6 prefix.";
      leaf up-down value {
      type boolean; rt-types:timer-value-seconds16;
      units "seconds";
      default 10;
      description
       "This leaf expresses defines the value interval of up/down bit.";
       hello messages.";
      }

      description
       "Interval between
       hello messages.";
    }

    grouping hello-multiplier-cfg {
      leaf ip-prefix value {
      type inet:ipv6-address; uint16;
      description
       "This leaf describes defines the IPv6 prefix"; number of
       hello failed to be received before
       declaring the adjacency down.";
      }
      leaf prefix-len {
        type uint8;
      description
       "This leaf describes grouping defines the IPv4 prefix len in bits"; number of
        hello failed to be received before
        declaring the adjacency down.";
    }

    grouping priority-cfg {
      leaf metric value {
          type wide-metric; uint8 {
            range "0 .. 127";

      }
      default 64;
      description
       "This leaf describes the ISIS metric value"; priority of
       the interface
       for DIS election.";
      }
      leaf-list tag {
        type uint32;

      description
       "This grouping leaf describes a list the
       priority of tags associated with
       the prefix."; interface
       for DIS election.";
    }
      leaf-list tag64

    grouping metric-cfg {
        leaf value {
          type uint64; wide-metric;
          description
         "This leaf describes a list of 64-bit tags associated with
         the prefix.";
           "Metric value.";
        }

      uses prefix-attributes-extension;
        description
         "Grouping for interface metric";
    }

    grouping neighbor-extended lfa-if-cfg {
      description
       "This group defines attributes of an
        ISIS extended neighbor.";
      leaf neighbor-id candidate-disabled {
        type system-id; boolean;
        default false;
        description
         "This leaf describes the system-id of
         "Prevent the neighbor."; interface to be used as backup.";
      }
      leaf metric enable {
        type wide-metric; boolean;
        description
         "This
         "Activates LFA.
         This model assumes activation
         of per-prefix LFA.";
      }

      container remote-lfa {
        if-feature remote-lfa;
        leaf describes the ISIS metric value"; enable {
          type boolean;
          description
          "Activates rLFA.";
        }
        description
         "remote LFA configuration.";
      }
      description
       "Grouping for LFA
       interface configuration";
    }

    grouping neighbor isis-global-cfg {
      description
       "This group defines attributes of an
       "Defines the ISIS standard neighbor."; global configuration.";

          uses admin-control;

          leaf neighbor-id level-type {
            type system-id; level;
            default "level-all";
            description
             "This leaf describes the system-id type of the neighbor."; ISIS node.
             A node can be level-1-only, level-2-only
             or level-1-2.
             ";
          }

          leaf i-e system-id {
            type boolean; system-id;
            description
             "This leaf expresses defines the value system-id of I/E bit."; the node.";
          }

          leaf default-metric maximum-area-addresses {
            if-feature maximum-area-addresses;
            type std-metric; uint8;
            default 3;
            description
         "This leaf describes
             "Defines the ISIS default metric value"; maximum areas supported.";
          }

          leaf-list area-address {
            type area-address;
            description
             "List of areas supported by the
             protocol instance.";
          }

          container delay-metric mpls {
            leaf metric ipv4-router-id {
              if-feature ipv4-router-id;
              type std-metric; inet:ipv4-address;
              description
           "This leaf describes the ISIS delay metric value";
               "Router ID value that would be used in
               TLV 134.";
            }
            leaf supported ipv6-router-id {
              if-feature ipv6-router-id;
              type boolean;
          default "false"; inet:ipv6-address;
              description
               "Router ID value that would be used in
               TLV 140.";
            }
            container ldp {
              container igp-sync {
                  if-feature ldp-igp-sync;
                  description
                  "This leaf describes if the metric is supported."; container may be augmented
                  with global parameters for igp-ldp-sync.";
              }
              description
               "LDP related configuration.";
            }
            description
              "This container defines the ISIS delay metric."; handles mpls config.";
          }
          container expense-metric auto-cost {
              if-feature auto-cost;
              leaf metric reference-bandwidth {
                type std-metric; uint32;
                units "bps";
                description
                 "This leaf describes defines the ISIS delay expense value"; bandwidth for calculating
                  metric.";
              }
              leaf supported enable {
                  type boolean;
                  default "false"; false;
                  description
           "This leaf describes if the metric is supported.";
                  "Enable/disable auto-cost.";
              }
              description
               "This container defines the ISIS expense metric."; auto-cost configuration.";
          }
      container error-metric {
          leaf metric lsp-mtu {
            type std-metric;
          description
           "This leaf describes the ISIS error metric value";
        }
        leaf supported {
          type boolean; uint16;
            units "bytes";
            default "false"; 1492;
            description
             "This leaf describes if the metric is supported.";
        }
        description
         "This container defines the ISIS error metric.";
      }
    }

    grouping database {
      description
       "This group defines attributes maximum size of an
        ISIS database (Link State DB).";
      leaf decoded-completed {
        type boolean;
        description
          "The OSPF LSA body is fully decoded.";
      }
      leaf raw-data {
        type yang:hex-string;
        description
          "The complete a
              LSP PDU in network byte
           order hexadecimal as received or originated."; bytes.";
          }
          leaf lsp-id lsp-lifetime {
            type lsp-id; uint16 {
              range "1..65535";
              }
            units "seconds";
            description
             "This leaf describes the LSP ID lifetime of the LSP."; router
              LSP in seconds.";
          }
          leaf checksum lsp-refresh {
            if-feature lsp-refresh;
            type uint16; rt-types:timer-value-seconds16;
            units "seconds";
            description
             "This leaf describes the checksum refresh interval of the LSP.";
              router LSP in seconds.";
          }
          container graceful-restart {
            if-feature graceful-restart;
            leaf remaining-lifetime enable {
              type uint16;
        units "seconds"; boolean;
              description
         "This leaf describes the remaining lifetime
          in seconds before
               "Control enabling the LSP expiration."; feature.";
            }
            leaf sequence restart-interval {
              type uint32; rt-types:timer-value-seconds16;
              units "seconds";
              description
         "This leaf describes the sequence number of the LSP.";
              "Interval in seconds to attempt graceful restart prior
             to failing";
            }
            leaf attributes helper-enable {
              type bits {
          bit PARTITIONNED { boolean;
              description
              "If set, enabled, the originator supports partition
              repair."; local router can act as restart helper.";
            }
          bit ATTACHED-ERROR {
            description
             "If set, the originator is attached to
              another area using the referred metric.";
             "This container activates graceful restart.";
          }
          bit ATTACHED-EXPENSE

          container nsr {
              if-feature nsr;
              description
             "If set, the originator is attached to
              another area using the referred metric.";
          }
          bit ATTACHED-DELAY
              "Non-Stop Routing (NSR) config state.";
              leaf enable {
                  type boolean;
                  description
             "If set, the originator is attached to
              another area using the referred metric.";
                   "Enable/Disable NSR.";
              }
          bit ATTACHED-DEFAULT
          }

          uses isis-node-tag-cfg;

          container authentication {
            description
             "If set, the originator is attached to
              another area using the referred metric.";
              uses authentication-global-cfg;

              container level-1 {
                  uses authentication-global-cfg;
                  description "level-1 specific cfg";
              }
          bit OVERLOAD
              container level-2 {
                  uses authentication-global-cfg;
                  description
             "If set, the originator is overloaded, "level-2 specific cfg";
              }
              description "authentication global cfg.
              It covers both LSPs and must be avoided in path calculation."; SNPs.";
          }

          container metric-type {
              uses metric-type-global-cfg;
              container level-1 {
                  uses metric-type-global-cfg;
                  description "level-1 specific cfg";
              }
              container level-2 {
                  uses metric-type-global-cfg;
                  description "level-2 specific cfg";
              }
              description
         "This leaf describes attributes of the LSP."; "Metric style global cfg.";
          }

          container is-neighbor default-metric {
        list neighbor
              uses default-metric-global-cfg;
              container level-1 {
                  uses neighbor; default-metric-global-cfg;
                  description
           "List of neighbors."; "level-1 specific cfg";
              }
              container level-2 {
                  uses default-metric-global-cfg;
                  description
         "This leaf describes list of ISIS neighbors.
         ISIS reference is TLV 2."; "level-2 specific cfg";
              }
              description "Default metric global cfg.";
          }
          container authentication afs {
              if-feature nlpid-control;
              list af {
                key af;
                leaf authentication-type af {
                  type string; identityref {
                    base rt-types:address-family;
                  }
                  description
           "This leaf describes the authentication type
            to be used.";
                   "Address-family";
                }
                leaf authentication-key enable {
                  type string; boolean;
                  description
           "This leaf describes the authentication key
            to be used. For security reason,
                    "Describes the
            authentication key MUST NOT be presented
            in plaintext format. Authors recommends
            to use MD5 hash to present activation state of the authentication-key.";
                     AF.";
                }
                description
                 "This container describes authentication
        information list permits activation
                 of the node. ISIS reference is TLV 10."; new address families.";
              }
              description
               "Container for address-families";
          }

          container extended-is-neighbor {
        list neighbor preference {
              uses neighbor-extended; route-preference-global-cfg;
              description
           "List of neighbors.";
               "This container defines the protocol preference.";
          }

          container overload {
              uses overload-global-cfg;
              description
             "This container describes list of ISIS extended
         neighbors.

         ISIS reference if the router is TLV 22.";
              set to overload state.";
          }

          container ipv4-internal-reachability {
        list prefixes overload-max-metric {
              if-feature overload-max-metric;
              uses prefix-ipv4-std;
          description
           "List of prefixes.";
        } overload-max-metric-global-cfg;
              description
             "This container describes list of IPv4 internal
         reachability information.
         ISIS reference if the router is TLV 128.";
              set to overload state using max-metric
              advertisement.";
          }

      leaf-list protocol-supported
    }
    grouping isis-global-topologies-cfg {
        type uint8;
     description
         "This leaf describes the list of
         supported protocols.
         ISIS reference is TLV 129.";
      }
      "Per topology config.";
      container ipv4-external-reachability default-metric {
        list prefixes
          uses default-metric-global-cfg;
          container level-1 {
              uses prefix-ipv4-std; default-metric-global-cfg;
              description
           "List of prefixes."; "level-1 specific cfg";
          }
        description
         "This
          container describes list of IPv4 external
         reachability information.
         ISIS reference is TLV 130."; level-2 {
              uses default-metric-global-cfg;
              description "level-2 specific cfg";
          }

      leaf-list ipv4-addresses
          description "Default metric per
          topology cfg.";
      }
      uses isis-node-tag-cfg;
    }

    grouping isis-if-cfg {
      description
       "Grouping for interface cfg.";

      leaf level-type {
        type inet:ipv4-address; level;
        default "level-all";
        description
         "This leaf describes defines the IPv4 addresses associated ISIS
         level of the node.
          ISIS reference is TLV 132."; interface.";
      }
      leaf ipv4-te-routerid lsp-pacing-interval {
        type inet:ipv4-address; rt-types:timer-value-milliseconds;
        units "milliseconds";
        default 33;
        description
         "This leaf describes the IPv4 Traffic Engineering
          router ID of defines the node.

          ISIS reference is TLV 134."; interval between
          LSP transmissions in milli-seconds";
      }

      container extended-ipv4-reachability {

        list prefixes
      leaf lsp-retransmit-interval {
          uses prefix-ipv4-extended;
          description
           "List of prefixes.";
        }
        type rt-types:timer-value-seconds16;
        units "seconds";
        description
         "This container describes list leaf defines the interval between
         retransmission of IPv4 extended
         reachability information.
         ISIS reference is TLV 135."; LSP";
      }
      leaf dynamic-hostname passive {
        type string; boolean;
        default "false";
        description
         "This leaf describes the name of the node.
         ISIS reference defines if interface is TLV 137."; in
          passive mode (ISIS not running,
          but network is advertised).";
      }
      leaf ipv6-te-routerid csnp-interval {
        type inet:ipv6-address; rt-types:timer-value-seconds16;
        units "seconds";
        default 10;
        description
         "This leaf describes defines the IPv6 Traffic Engineering
          router ID interval of the node.
          ISIS reference is TLV 140."; CSNP
          messages.";
      }
      container mt-is-neighbor {
        list neighbor hello-padding {
        leaf MT-ID enable {
          type uint16 {
              range "0 .. 4095";
            }
            description
             "This leaf defines the identifier
              of a topology.";
          }
          uses neighbor-extended; boolean;
          default "true";
          description
           "List
           "Status of neighbors."; Hello-padding activation.
            By default, the implementation shall
            pad HELLOs.";
        }
        description
         "This container describes list of ISIS multi-topology
          neighbors. handles ISIS reference is TLV 223."; hello padding
          configuration.";
      }

      container mt-entries {
        list topology {
      leaf MT-ID mesh-group-enable {
        type uint16 {
              range "0 .. 4095";
            } mesh-group-state;
        description
             "This leaf defines
         "Describes the identifier mesh group state of a topology.";
          the interface.";
      }
      leaf attributes {
            type bits mesh-group {
              bit OVERLOAD
        when "../mesh-group-enable = 'meshSet'" {
          description
                 "If set, the originator is overloaded,
                  and must be avoided in path
                  calculation.";
           "Only valid when mesh-group-enable
            equals meshSet";
        }
              bit ATTACHED {
        type uint8;
        description
                 "If set,
         "Describes the originator is attached to
                  another area using mesh group ID of
          the referred metric.";
              } interface.";
      }
      leaf interface-type {
        type interface-type;
        description
         "This leaf describes attributes defines the type of adjacency
         to be established on the LSP
              for interface.

         This is affecting the associated topology.";
          }
          description
           "List type of topologies supported."; hello
         message that would be used.";
      }

      uses admin-control;

      leaf-list tag {
        if-feature prefix-tag;
        type uint32;
        description
         "This container describes leaf defines list of tags associated
          with the topology supported.
         ISIS reference is TLV 229."; interface.";
      }
      leaf-list ipv6-addresses tag64 {
        if-feature prefix-tag64;
        type inet:ipv6-address; uint64;
        description
         "This leaf describes the IPv6 interface
         addresses defines list of 64bits tags
         associated with the node.

         ISIS reference is TLV 232."; interface.";
      }

      container mt-extended-ipv4-reachability {
        list prefixes {
      leaf MT-ID node-flag {
          if-feature node-flag;
          type uint16 {
              range "0 .. 4095";
            } boolean;
          default false;
          description
             "This leaf defines the identifier
              of
           "Set prefix as a topology."; node
           representative prefix.";
      }
      container hello-authentication {
          uses prefix-ipv4-extended;
          description
           "List of prefixes.";

        } hello-authentication-cfg;
          container level-1 {
              uses hello-authentication-cfg;
              description
         "This "level-1 specific cfg";
          }
          container describes list of IPv4
         reachability information level-2 {
              uses hello-authentication-cfg;
              description "level-2 specific cfg";
          }
          description "Authentication type
         to be used in multi-topology
         environment.
         ISIS reference is TLV 235."; hello messages.";
      }
      container mt-ipv6-reachability {
        list prefixes hello-interval {
          leaf MT-ID
          uses hello-interval-cfg;
          container level-1 {
            type uint16
              uses hello-interval-cfg;
              description "level-1 specific cfg";
          }
          container level-2 {
              range "0 .. 4095";
              uses hello-interval-cfg;
              description "level-2 specific cfg";
          }
          description
             "This leaf defines the identifier
              of a topology."; "Interval between
           hello messages.";
      }
      container hello-multiplier {
          uses prefix-ipv6-extended; hello-multiplier-cfg;
          container level-1 {
              uses hello-multiplier-cfg;
              description
           "List of prefixes."; "level-1 specific cfg";
          }
          container level-2 {
              uses hello-multiplier-cfg;
              description
         "This "level-2 specific cfg";
          }
          description "Hello multiplier
          configuration.";
      }
      container describes list of IPv6
         reachability information in multi-topology
         environment.
         ISIS reference is TLV 237."; priority {
          must '../interface-type = "broadcast"' {
              error-message
               "Priority only applies to broadcast
               interfaces.";
              description
               "Check for broadcast interface.";
          }
          uses priority-cfg;
          container ipv6-reachability level-1 {
        list prefixes
              uses priority-cfg;
              description "level-1 specific cfg";
          }
          container level-2 {
              uses prefix-ipv6-extended; priority-cfg;
              description
           "List of prefixes."; "level-2 specific cfg";
          }
          description
         "This "Priority for DIS election.";
      }
      container describes list of IPv6
         reachability information.
         ISIS reference is TLV 236."; metric {
          uses metric-cfg;
          container level-1 {
              uses metric-cfg;
              description "level-1 specific cfg";
          }

      list router-capabilities
          container level-2 {
              uses metric-cfg;
              description "level-2 specific cfg";
          }
          description "Metric configuration.";
      }
      container bfd {
          if-feature bfd;
          leaf flags enable {
              type bits {
            bit flooding {
              position 0; boolean;
              default false;
              description
               "If the S bit is set(1),
               the IS-IS Router CAPABILITY TLV
              MUST be flooded across "
                  Enables BFD on the entire routing domain.
              If the S bit is
              not set(0), the TLV MUST NOT be leaked between levels.
              This bit MUST NOT be altered during the TLV leaking.";
            }
            bit down {
              position 1;
              description
              "When the IS-IS Router CAPABILITY TLV is
              leaked from level-2 to level-1, the D bit
              MUST be set.  Otherwise, this bit MUST
              be clear.  IS-IS Router capability TLVs
              with the D bit set MUST NOT
              be leaked from level-1 to level-2.
              This is to prevent TLV looping. interface
              ";
          }
          }
          description
           "Flags associated with router capability.";
           "BFD configuration.";
      }
      container node-tags afs {
          if-feature node-tag; nlpid-control;
          list node-tag af {
            key af;
            leaf tag af {
              type uint32; identityref {
                base rt-types:address-family;
              }
              description
               "Node tag value.";
                "Address-family";
            }
            description
             "List of tags."; AFs.";
          }
          description
               "Container for node tags."; address-families";
      }
      container mpls {
        container ldp {
          leaf binary igp-sync {
              if-feature ldp-igp-sync;
              type binary; boolean;
              description
           "This leaf describes the capability of the node.
           Format is binary according to the
               "Enables IGP/LDP sync.";
          }
          description
           "LDP protocol encoding."; related configurations.";
        }
        description
         "This container describes the capabilities of the node.
         This container may be extended with detailed
         information.
         ISIS reference is TLV 242.";
         "Container for MPLS specific configuration
         for ISIS.";
      }
    }
    grouping isis-node-tag-cfg isis-if-topologies-cfg {
      description
       "ISIS node tag config."; interface topology cfg.";
      container node-tags {
          if-feature node-tag;
          list node-tag metric {
            key tag;
            leaf tag
          uses metric-cfg;
          container level-1 {
              type uint32;
              uses metric-cfg;
              description
               "Node tag value."; "level-1 specific cfg";
          }
          container level-2 {
              uses metric-cfg;
              description
             "List of tags."; "level-2 specific cfg";
          }
          description
            "Container for node tags."; "Metric configuration.";
      }
    }

    grouping authentication-global-cfg system-counters {
          choice authentication-type
     container system-counters {
              case key-chain
        list level {
                if-feature key-chain;
          key level;

          leaf key-chain level {
            type key-chain:key-chain-ref; level-number;
            description
                    "Reference to a key-chain.";
                }
              }
              case password {
                leaf key {
                  type string;
                  description
                   "This
             "This leaf describes the
                     authentication key."; ISIS level.";
          }
          leaf crypto-algorithm corrupted-lsps {
            type identityref {
                      base key-chain:crypto-algorithm;
                  }
                  description
                    "Cryptographic algorithm associated with key.";
                }
              } uint32;
            description
                 "Choice
             "Number of authentication.";
            }
           description
            "Grouping for global auth config."; corrupted in-memory LSPs detected.
             LSPs received from the wire with a bad
             checksum are silently dropped and not counted.
             LSPs received from the wire with parse errors
             are counted by lsp-errors.";
          }

    grouping metric-type-global-cfg {
          leaf value authentication-type-fails {
            type enumeration {
                enum wide-only { uint32;
            description
                   "Advertise new metric style only
                   (RFC5305)";
             "Number of authentication type mismatches.";
          }
                enum old-only
          leaf authentication-fails {
            type uint32;
            description
                   "Advertise old metric style only
                   (RFC1195)";
             "Number of authentication key failures.";
          }
                enum both
          leaf database-overload {
            type uint32;
            description "Advertise both metric
                  styles";
                }
             "Number of times the database has become
             overloaded.";
          }
              description
               "This
          leaf describes the own-lsp-purge {
            type uint32;
            description
             "Number of metric
               to be generated.
               Wide-only means only new metric style
               is generated,
               old-only means that only old style metric
               is generated,
               and both means that both are advertised.
               This leaf times a zero-aged copy of the
             system's own LSP is only affecting IPv4 metrics.";
            }
             description
            "Grouping for global metric style config."; received from some
             other node.";
          }

    grouping default-metric-global-cfg {
          leaf value manual-address-drop-from-area {
            type wide-metric;
              default "10"; uint32;
            description
                "Value
             "Number of times a manual address
              has been dropped from the metric";
            }
      description
            "Grouping for global default metric config."; area.";
          }

   grouping overload-global-cfg {
          leaf status max-sequence {
            type boolean; uint32;
            description
           "This leaf defines
             "Number of times the overload status.";
      }
            description
        "Grouping for overload bit config."; system has attempted
              to exceed the maximum sequence number.";
          }
  grouping overload-max-metric-global-cfg {
          leaf timeout sequence-number-skipped {
            type uint16;
          units "seconds"; uint32;
            description
           "This leaf defines the timeout in seconds
             "Number of the overload condition.";
        }
        description
        "Grouping for overload-max-metric config."; times a sequence number skip has
             occured.";
          }

   grouping route-preference-global-cfg {
      choice granularity {
              case detail {
          leaf internal id-len-mismatch {
            type uint8; uint32;
            description
                    "This leaf defines the protocol
                     preference
             "Number of times a PDU is received with
              a different value for internal routes.";
                }
                leaf external {
                  type uint8;
                  description
                    "This leaf defines ID field length
              from that of the protocol
                     preference for external routes.";
                } receiving system.";
          }
              case coarse {
          leaf default partition-changes {
            type uint8;
                  description
                    "This leaf defines the protocol
                     preference for all ISIS routes.";
                }
              } uint32;
            description
               "Choice for implementation
             "Number of route preference.";
            }
      description
       "This grouping defines how route preference is configured."; partition changes detected.";
          }

  grouping hello-authentication-cfg {
      choice authentication-type {
          case key-chain {
            if-feature key-chain;
          leaf key-chain lsp-errors {
            type key-chain:key-chain-ref; uint32;
            description
                "Reference to a key-chain.";
            }
             "Number of LSPs with errors we have
             received.";
          }
          case password {
          leaf key spf-runs {
            type string; uint32;
            description
               "This leaf describes the
                 authentication key.";
            }
            leaf crypto-algorithm {
              type identityref {
                  base key-chain:crypto-algorithm;
             "Number of times we ran SPF at this level.";
          }
          description
                "Cryptographic algorithm associated with key.";
            }
           "List of supported levels.";
        }
        description
             "Choice
         "The container defines a list of authentication."; counters
          for the IS.";
      }
      description
       "Grouping for hello authentication."; system counters.";
    }

    grouping hello-interval-cfg event-counters {
        container event-counters {
            leaf value adjacency-changes {
              type uint16 {
              range "1..65535";
              }
          units "seconds";
          default 10; uint32;
              description
           "This leaf defines the interval
               "The number of
           hello messages.";
        }

        description
           "Interval between
           hello messages."; times an adjacency state
                change has occured on this interface.";
            }

      grouping hello-multiplier-cfg {
            leaf value adjacency-number {
              type uint16; uint32;
              description
           "This leaf defines the
               "The number of
           hello failed to be received before
           declaring the adjacency down."; adjacencies on this
                interface.";
            }
            leaf init-fails {
              type uint32;
              description
           "This grouping defines the
               "The number of
            hello failed times initialization of
                this interface has failed. This counts
                events such as PPP NCP failures.
                Failures to be received before
            declaring the form an adjacency down."; are counted
                by adjacency-rejects.";
            }

      grouping priority-cfg {
            leaf value adjacency-rejects {
              type uint8 {
            range "0 .. 127";
          }
          default 64; uint32;
              description
           "This leaf describes the priority
               "The number of
           the interface
           for DIS election."; times an adjacency has been
                rejected on this interface.";
            }

        description
           "This grouping
            leaf describes the
           priority id-len-mismatch {
              type uint32;
              description
               "The number of
           the interface times an IS-IS PDU with an ID
                field length different from that for DIS election."; this
                system has been received on this interface.";
            }

      grouping metric-cfg {
            leaf value max-area-addresses-mismatch {
              type wide-metric;
          description
           "Metric value.";
        } uint32;
              description
         "Grouping
               "The number of times an IS-IS PDU with
                according max area address field
                differs from that for interface metric";
                this system has been received on this
                interface.";
            }
      grouping lfa-if-cfg {
            leaf candidate-disabled authentication-type-fails {
              type boolean;
            default false; uint32;
              description
             "Prevent the interface to be used as backup.";
               "Number of authentication type mismatches.";
            }
            leaf enable authentication-fails {
              type boolean; uint32;
              description
             "Activates LFA.
             This model assumes activation
               "Number of per-prefix LFA."; authentication key failures.";
            }

          container remote-lfa {
            if-feature remote-lfa;
            leaf enable lan-dis-changes {
              type boolean; uint32;
              description
              "Activates rLFA.";
               "The number of times the DIS has changed
                on this interface at this level.
                If the interface type is point to point,
                the count is zero.";
            }
            description
             "remote LFA configuration.";
             "Provides protocol event counters.";
        }
        description
         "Grouping for LFA
           interface configuration"; event counters";
    }

    grouping isis-global-cfg packet-counters {
      description
       "Defines the ISIS global configuration.";

          uses admin-control;
      container packet-counters {
        list level {
          key level;

          leaf level-type level {
            type level;
            default "level-all"; level-number;
            description
             "This leaf describes the type of ISIS node.
             A node can be level-1-only, level-2-only
             or level-1-2.
             "; level.";
          }
          container iih {
            leaf system-id in {
              type system-id; uint32;
              description
             "This leaf defines the system-id of the node.";
               "Received PDUs.";
            }
            leaf maximum-area-addresses out {
            if-feature maximum-area-addresses;
              type uint8;
            default 3; uint32;
              description
             "Defines the maximum areas supported.";
               "Sent PDUs.";
            }

          leaf-list area-address {
            type area-address;
            description
             "List
             "The number of areas supported by the
             protocol instance."; IIH PDUs received/sent.";
          }
          container mpls ish {
            leaf ipv4-router-id in {
              if-feature ipv4-router-id;
              type inet:ipv4-address; uint32;
              description
               "Router ID value that would be used in
               TLV 134.";
               "Received PDUs.";
            }
            leaf ipv6-router-id out {
              if-feature ipv6-router-id;
              type inet:ipv6-address; uint32;
              description
               "Router ID value that would be used in
               TLV 140.";
               "Sent PDUs.";
            }
            description
             "The number of ISH PDUs received/sent.";
          }
          container ldp esh {
              container igp-sync
            leaf in {
                  if-feature ldp-igp-sync;
              type uint32;
              description
                  "This container may be augmented
                  with global parameters for igp-ldp-sync.";
               "Received PDUs.";
            }
            leaf out {
              type uint32;
              description
               "LDP related configuration.";
               "Sent PDUs.";
            }
            description
              "This container handles mpls config.";
             "The number of ESH PDUs received/sent.";
          }
          container auto-cost lsp {
              if-feature auto-cost;
            leaf reference-bandwidth in {
              type uint32;
                units "bps";
              description
                 "This leaf defines the bandwidth for calculating
                  metric.";
               "Received PDUs.";
            }
            leaf enable out {
              type boolean;
                  default false; uint32;
              description
                  "Enable/disable auto-cost.";
               "Sent PDUs.";
            }
            description
               "This container defines the auto-cost configuration.";
             "The number of LSP PDUs received/sent.";
          }
          container psnp {
            leaf lsp-mtu in {
              type uint16;
            units "bytes";
            default 1492; uint32;
              description
             "This leaf describes the maximum size of a
              LSP PDU in bytes.";
               "Received PDUs.";
            }
            leaf lsp-lifetime out {
              type uint16 {
              range "1..65535"; uint32;
              description
               "Sent PDUs.";
            }
            units "seconds";
            description
             "This leaf describes the lifetime
             "The number of the router
              LSP in seconds."; PSNP PDUs received/sent.";
          }
          container csnp {
            leaf lsp-refresh in {
            if-feature lsp-refresh;
              type uint16 uint32;
              description
               "Received PDUs.";
            }
            leaf out {
              range "1..65535";
              type uint32;
              description
               "Sent PDUs.";
            }
            units "seconds";
            description
             "This leaf describes the refresh interval
             "The number of the
              router LSP in seconds."; CSNP PDUs received/sent.";
          }
          container spf-control unknown {
              container ietf-spf-delay
            leaf in {
                  if-feature ietf-spf-delay;
                  uses ietf-spf-delay-cfg;
              type uint32;
              description
                   "IETF spf delay algorithm configuration.";
               "Received PDUs.";
            }
            leaf out {
              type uint32;
              description
               "Sent PDUs.";
            }
            description
               "Container
             "The number of unknown PDUs received/sent.";

          }
          description
           "List of supported levels.";
        }
        description
         "Provides packet counters per level.";
      }
      description
       "Grouping for all SPF computation related
               operations."; packet counters.";
    }

    grouping spf-log {
      container graceful-restart spf-log {
            if-feature graceful-restart;
        list event {
          key id;

          leaf enable id {
            type boolean; uint32;
            description
               "Control enabling
             "This leaf defines the feature."; event identifier.
              This is a purely internal value.";
          }
          leaf restart-interval spf-type {
            type uint16;
              units "seconds"; enumeration {
              enum full {
                description
              "Interval in seconds to attempt graceful restart prior
             to failing";
                 "Computation done is a Full SPF.";
              }
            leaf helper-enable
              enum route-only {
              type boolean;
                description
              "If enabled, the local router can act as restart helper.";
                 "Computation done is a
                  reachability computation
                  only.";
              }
            }
            description
             "This container activates graceful restart."; leaf describes the type of computation
             used.";
          }

          container nsr
          leaf level {
              if-feature nsr;
            type level-number;
            description
              "Non-Stop Routing (NSR) config state.";
             "This leaf enable describes the level affected by the
             the computation.";
          }
          leaf schedule-timestamp {
            type boolean; yang:timestamp;
            description
                   "Enable/Disable NSR.";
              }
             "This leaf describes the timestamp
              when the computation was scheduled.";
          }

          uses isis-node-tag-cfg;

          container authentication {
              uses authentication-global-cfg;

              container level-1
          leaf start-timestamp {
                  uses authentication-global-cfg;
            type yang:timestamp;
            description "level-1 specific cfg";
             "This leaf describes the timestamp
              when the computation was started.";
          }
              container level-2
          leaf end-timestamp {
                  uses authentication-global-cfg;
                  description "level-2 specific cfg";
              }
            type yang:timestamp;
            description "authentication global cfg.
              It covers both LSPs and SNPs.";
             "This leaf describes the timestamp
              when the computation was ended.";
          }

          container metric-type
          list trigger-lsp {
              uses metric-type-global-cfg;

              container level-1
            key "lsp";
            leaf lsp {
                  uses metric-type-global-cfg;
              type lsp-id;
              description "level-1 specific cfg";
               "This leaf describes the LSPID
                of the LSP.";
            }
              container level-2
            leaf sequence {
                  uses metric-type-global-cfg;
              type uint32;
              description "level-2 specific cfg";
               "This leaf describes the sequence
                number of the LSP.";
            }
            description "Metric style global cfg.";
             "This leaf describes list of LSPs
              that triggered the computation.";
          }

          container default-metric {
              uses default-metric-global-cfg;

              container level-1 {
                  uses default-metric-global-cfg;
          description "level-1 specific cfg";
           "List of computation events.
           It is used as a wrapping buffer.";
        }
              container level-2 {
                  uses default-metric-global-cfg;

        description "level-2 specific cfg";
         "This container lists the SPF computation events.";
      }
      description "Default metric global cfg.";
       "Grouping for spf-log events.";
    }

    grouping lsp-log {
      container afs lsp-log {
              if-feature nlpid-control;
        list af event {
          key af; id;

          leaf af id {
            type identityref {
                    base rt:address-family;
                  } uint32;
            description
                   "Address-family";
             "This leaf defines the event identifier.
              This is a purely internal value.";
          }
          leaf enable level {
            type boolean; level-number;
            description
                    "Describes
             "This leaf describes the activation state of level affected by the
                     AF.";
             the computation.";
          }
          container lsp {
            leaf lsp {

              type lsp-id;
              description
               "This list permits activation leaf describes the LSPID
                of new address families.";

              }
              description
               "Container for address-families"; the LSP.";
            }
          container preference
            leaf sequence {
              uses route-preference-global-cfg;
              type uint32;
              description
               "This container defines leaf describes the protocol preference."; sequence
                number of the LSP.";
            }

          container overload {

              uses overload-global-cfg;
            description
             "This container describes if the router is
              set to overload state."; received LSP
             , in case of local LSP update the local
             LSP ID is referenced.";
          }

          container overload-max-metric

          leaf received-timestamp {
              if-feature overload-max-metric;
              uses overload-max-metric-global-cfg;
            type yang:timestamp;

            description
             "This container leaf describes if the router is
              set timestamp
             when the LSP was received. In case of
             local LSP update, the timestamp refers
             to overload state using max-metric
              advertisement.";
          } the local LSP update time.";
          }

    grouping isis-global-topologies-cfg {
     description
      "Per topology config.";

      container default-metric

          leaf change {
              uses default-metric-global-cfg;

              container level-1
            type identityref {
                  uses default-metric-global-cfg;
                  description "level-1 specific cfg";
              base lsp-log-reason;
            }
              container level-2 {
                  uses default-metric-global-cfg;
            description "level-2 specific cfg";
             "This leaf describes the type of change
             in the LSP.";
          }

          description "Default metric per
              topology cfg.";
           "List of LSP events.
           It is used as a wrapping buffer.";
        }

        uses isis-node-tag-cfg;

        description
         "This container lists the LSP reception events.
         Local LSP modification are also contained in the
         list.";
      }

    grouping isis-if-cfg {
      description
       "Grouping for interface cfg."; LSP log.";
    }

    grouping hostname-db {
      container hostnames {
        list hostname {
          key system-id;
          leaf level-type system-id {
            type level;
        default "level-all"; system-id;
            description
             "This leaf defines describes the system-id
             associated ISIS
         level of with the interface."; hostname.";
          }
          leaf lsp-pacing-interval hostname {
            type uint16;
        units "milliseconds";
        default 33; string;
            description
             "This leaf defines describes the interval hostname
              associated with the system ID.";
          }
          description
           "List of system-id/hostname associations";
        }
        description
         "This container describes the list
         of binding between
          LSP transmissions in milli-seconds"; system-id and
         hostnames.";
      }
      leaf lsp-retransmit-interval
      description
       "Grouping for hostname to systemid mapping database.";
    }

    /* Groupings for the LSDB description */
    grouping prefix-reachability-attributes {
        type uint16;
        units "seconds";
      description
       "This leaf group defines the interval between
         retransmission extended reachability attributes of LSP";
      } an
        IPv4 or IPv6 prefix.";

      leaf passive external-prefix-flag {
          type boolean;
        default "false";
          description
         "This
           "External prefix flag.";
      }
      leaf defines if interface is in
          passive mode (ISIS not running,
          but network is advertised)."; readvertisement-flag {
          type boolean;
          description
           "Readvertisement flag.";
      }
      leaf csnp-interval node-flag {
          type uint16 {
              range "1..65535"; boolean;
          description
           "Node flag.";
      }
        units "seconds";
        default 10;
    }

    grouping prefix-ipv4-source-router-id {
      description
       "This leaf group defines the interval IPv4 source router ID of CSNP
          messages.";
      }
      container hello-padding {
       a prefix advertisement.";

      leaf enable ipv4-source-router-id {
          type boolean;
          default "true"; inet:ipv4-address;
          description
           "Status of Hello-padding activation.
            By default, the implementation shall
            pad HELLOs.";
           "IPv4 Source router ID address.";
      }

        description
         "This container handles ISIS hello padding
          configuration.";
    }

      leaf mesh-group-enable

    grouping prefix-ipv6-source-router-id {
        type mesh-group-state;
      description
         "Describes the mesh
       "This group state of defines the interface.";
      } IPv6 source router ID of
       a prefix advertisement.";

      leaf mesh-group ipv6-source-router-id {
        when "../mesh-group-enable = 'meshSet'"
          type inet:ipv6-address;
          description
           "IPv6 Source router ID address.";
      }
    }

    grouping prefix-attributes-extension {
      description
           "Only valid when mesh-group-enable
            equals meshSet";
       "Prefix extended attributes.";

      uses prefix-reachability-attributes;
      uses prefix-ipv4-source-router-id;
      uses prefix-ipv6-source-router-id;
    }
        type uint8;

    grouping prefix-ipv4-std {
      description
         "Describes the mesh
       "This group ID defines attributes of
          the interface.";
      } an
        IPv4 standard prefix.";
      leaf interface-type up-down {
        type interface-type; boolean;
        description
         "This leaf defines the type of adjacency
         to be established on the interface.
         This is affecting expresses the type value of hello
         message that would be used."; up/down bit.";
      }

      uses admin-control;

      leaf-list tag
      leaf i-e {
        if-feature prefix-tag;
        type uint32; boolean;
        description
         "This leaf defines list of tags associated
          with expresses the interface."; value of I/E bit.";
      }

      leaf-list tag64
      leaf ip-prefix {
        if-feature prefix-tag64;
        type uint64; inet:ipv4-address;
        description
         "This leaf defines list of 64bits tags
         associated with describes the interface."; IPv4 prefix";
      }
      leaf node-flag prefix-len {
          if-feature node-flag;
        type boolean;
          default false; uint8;
        description
           "Set
         "This leaf describes the IPv4 prefix as a node
           representative prefix."; len in bits";
      }

      container hello-authentication {
          uses hello-authentication-cfg;

          container level-1
      leaf default-metric {
              uses hello-authentication-cfg;
              description "level-1 specific cfg";
          }
          container level-2 {
              uses hello-authentication-cfg;
              description "level-2 specific cfg";
          }
          description "Authentication
        type
         to be used in hello messages."; std-metric;
        description
         "This leaf describes the ISIS default metric value";
      }
      container hello-interval delay-metric {
          uses hello-interval-cfg;

          container level-1
        leaf metric {
              uses hello-interval-cfg;
          type std-metric;
          description "level-1 specific cfg";
           "This leaf describes the ISIS delay metric value";
        }
          container level-2
        leaf supported {
              uses hello-interval-cfg;
          type boolean;
          default "false";
          description "level-2 specific cfg";
           "This leaf describes if the metric is supported.";
        }
        description "Interval between
           hello messages.";
         "This container defines the ISIS delay metric.";
      }
      container hello-multiplier expense-metric {
          uses hello-multiplier-cfg;

          container level-1
        leaf metric {
              uses hello-multiplier-cfg;
          type std-metric;
          description "level-1 specific cfg";
           "This leaf describes the ISIS expense metric value";
        }
          container level-2
        leaf supported {
              uses hello-multiplier-cfg;
              description "level-2 specific cfg";
          }
          type boolean;
          default "false";
          description "Hello multiplier
          configuration.";
           "This leaf describes if the metric is supported.";
        }

      container priority {
          must '../interface-type = "broadcast"' {
          error-message
           "Priority only applies to broadcast
           interfaces.";
        description
           "Check for broadcast interface.";
        }
          uses priority-cfg;
         "This container level-1 {
              uses priority-cfg;
              description "level-1 specific cfg"; defines the ISIS expense metric.";
      }
      container level-2 error-metric {
              uses priority-cfg;
              description "level-2 specific cfg";
          }
          description "Priority for DIS election.";
      }

      container
        leaf metric {
          uses metric-cfg;
          container level-1 {
              uses metric-cfg;
              description "level-1 specific cfg";
          }
          container level-2 {
              uses metric-cfg;
              description "level-2 specific cfg";
          }
          type std-metric;
          description "Metric configuration.";
           "This leaf describes the ISIS error metric value";
        }

      container bfd {
          if-feature bfd;
        leaf enable supported {
          type boolean;
          default false; "false";
          description "
                  Enables BFD on
           "This leaf describes if the interface
              "; metric is supported.";
        }

        description
           "BFD configuration.";
      }
         "This container afs {
          if-feature nlpid-control;
          list af defines the ISIS error metric.";
      }
    }

    grouping prefix-ipv4-extended {
            key af;
      description
       "This group defines attributes of an
        IPv4 extended prefix.";
      leaf af up-down {
        type identityref {
                base rt:address-family;
              }
              description
                "Address-family";
            } boolean;
        description
             "List
         "This leaf expresses the value of AFs."; up/down bit.";
      }
      leaf ip-prefix {
        type inet:ipv4-address;
        description
               "Container for address-families";
         "This leaf describes the IPv4 prefix";
      }

      container mpls {
        container ldp
      leaf prefix-len {
        type uint8;
        description
         "This leaf igp-sync describes the IPv4 prefix len in bits";
      }

      leaf metric {
              if-feature ldp-igp-sync;
        type boolean; wide-metric;
        description
               "Enables IGP/LDP sync.";
         "This leaf describes the ISIS metric value";
      }
      leaf-list tag {
        type uint32;
        description
           "LDP protocol related configurations.";
         "This leaf describes a list of tags associated with
         the prefix.";
      }
      leaf-list tag64 {
        type uint64;
        description
         "Container for MPLS specific configuration
         for ISIS.";
         "This leaf describes a list of 64-bit tags associated with
         the prefix.";
      }
      uses prefix-attributes-extension;
    }

    grouping isis-if-topologies-cfg prefix-ipv6-extended {
      description
       "ISIS interface topology cfg.";
      container metric {
          uses metric-cfg;

          container level-1
       "This group defines attributes of an
        IPv6 prefix.";
      leaf up-down {
              uses metric-cfg;
        type boolean;
        description "level-1 specific cfg";
         "This leaf expresses the value of up/down bit.";
      }
          container level-2
      leaf ip-prefix {
              uses metric-cfg;
              description "level-2 specific cfg";
          }
        type inet:ipv6-address;
        description "Metric configuration.";
      }
         "This leaf describes the IPv6 prefix";
      }

    /* */

    augment "/rt:routing-state/"
      +"rt:ribs/rt:rib/rt:routes/rt:route" {
      when "rt:source-protocol = 'isis:isis'"
      leaf prefix-len {
        description "ISIS-specific route attributes.";
      }
      uses route-content;
        type uint8;
        description
         "This augments route object leaf describes the IPv4 prefix len in RIB with ISIS-specific
        attributes."; bits";
      }

    augment "/if:interfaces/if:interface"
       {
      leaf clns-mtu metric {
        type uint16; wide-metric;
        description
         "Defines CLNS MTU of
         "This leaf describes the interface."; ISIS metric value";
      }
      leaf-list tag {
        type uint32;
        description "ISO interface config.";
         "This leaf describes a list of tags associated with
         the prefix.";
      }

    augment "/rt:routing/rt:control-plane-protocols/"
        +"rt:control-plane-protocol" {
      when "rt:type = 'isis:isis'"
      leaf-list tag64 {
        description
         "This augment is only valid when routing protocol
          instance
        type is isis.";
      } uint64;
        description
         "This augments leaf describes a routing protocol instance list of 64-bit tags associated with ISIS
        specific parameters.";
      container isis
         the prefix.";
      }
      uses prefix-attributes-extension;
    }

    grouping neighbor-extended {

          must "count(area-address) > 0"
      description
       "This group defines attributes of an
        ISIS extended neighbor.";
      leaf neighbor-id {
            error-message "At least one area-address
            must be configured.";
        type system-id;
        description
             "Enforce configuration
         "This leaf describes the system-id of at least one area."; the neighbor.";
      }

          uses isis-global-cfg;

          container fast-reroute
      leaf metric {
           if-feature fast-reroute;
           uses fast-reroute-global-cfg;
        type wide-metric;
        description
                "IPFRR.";
         "This leaf describes the ISIS metric value";
      }
          container topologies {
              if-feature multi-topology;
              list topology
    }

    grouping neighbor {

                key "name";
      description
       "This group defines attributes of an
        ISIS standard neighbor.";
      leaf enable neighbor-id {
        type boolean; system-id;
        description
                   "Control enabling
         "This leaf describes the system-id of topologies"; the neighbor.";
      }
      leaf name i-e {
        type leafref {
                     path "../../../../../../rt:ribs/rt:rib/rt:name";
                   }

                  description "RIB";
                }

                uses isis-global-topologies-cfg; boolean;
        description
                  "List
         "This leaf expresses the value of topologies"; I/E bit.";

      }
      leaf default-metric {
        type std-metric;
        description
               "Container for multi-topology";
         "This leaf describes the ISIS default metric value";
      }
      container interfaces {
            list interface delay-metric {
              key "name";
        leaf name metric {
          type if:interface-ref; std-metric;
          description
                 "Reference to the interface within
           "This leaf describes the routing-instance."; ISIS delay metric value";
        }

            uses isis-if-cfg;
            container fast-reroute
        leaf supported {
              if-feature fast-reroute;
              uses fast-reroute-if-cfg;
          type boolean;
          default "false";
          description
                "IPFRR.";
           "This leaf describes if the metric is supported.";
        }
        description
         "This container topologies defines the ISIS delay metric.";
      }
      container expense-metric {
                if-feature multi-topology;
                list topology {
                    key name;
        leaf name metric {
          type leafref {
                          path "../../../../../../../../"+
                          "rt:ribs/rt:rib/rt:name";
                      }
                      description
                       "Name of RIB.";
                    }
                    uses isis-if-topologies-cfg;
                    description
                     "List of topologies.";
                }
              description
               "Container for multi-topology";
            } std-metric;
          description
              "List of
           "This leaf describes the ISIS interfaces."; delay expense value";
        }
        leaf supported {
          type boolean;
          default "false";
          description
           "This container defines ISIS interface specific
             configuration objects."; leaf describes if the metric is supported.";
        }
        description
         "This container defines the ISIS specific configuration
          objects.";
      } expense metric.";
      }

    augment "/rt:routing-state/"
      +"rt:control-plane-protocols/rt:control-plane-protocol"
      container error-metric {
      when "rt:type = 'isis:isis'"
        leaf metric {
          type std-metric;
          description
           "This augment is only valid when routing protocol
          instance leaf describes the ISIS error metric value";
        }
        leaf supported {
          type boolean;
          default "false";
          description
           "This leaf describes if the metric is isis."; supported.";
        }
        description
         "This augments routing protocol instance states with ISIS
        specific parameters.";

      container isis {
        config false;
          uses isis-global-cfg; container fast-reroute defines the ISIS error metric.";
      }
    }

    grouping lsp-entry {
            if-feature fast-reroute;
            uses fast-reroute-global-cfg;
            uses fast-reroute-global-state;
     description
             "IPFRR states.";
          }
          container ietf-spf-delay
       "This group defines attributes of an
        ISIS LSP database entry.";

      leaf decoded-completed {
              if-feature ietf-spf-delay;
              uses ietf-spf-delay-cfg;
              uses ietf-spf-delay-state;
        type boolean;
        description
               "IETF SPF delay operational states.";
          "The IS-IS body is fully decoded.";
      }
          uses local-rib;
          list topologies {
            key name;
      leaf name raw-data {
        type leafref {
                 path "../../../../../"
                 +"rt:ribs/rt:rib/rt:name";
               } yang:hex-string;
        description
                "Name of RIB.";
          "The complete LSP in network byte
           order hexadecimal as received or originated.";
      }
            uses local-rib;
      leaf lsp-id {
        type lsp-id;
        description
             "List
         "This leaf describes the LSP ID of topologies."; the LSP.";
      }

          container system-counters {
            list level {
              key level;
      leaf level checksum {
        type level-number; uint16;
        description
         "This leaf describes the ISIS level."; checksum of the LSP.";
      }
      leaf corrupted-lsps remaining-lifetime {
        type uint32; uint16;
        units "seconds";
        description
                 "Number of corrupted in-memory LSPs detected.
                 LSPs received from
         "This leaf describes the wire with a bad
                 checksum are silently dropped and not counted.
                 LSPs received from remaining lifetime
          in seconds before the wire with parse errors
                 are counted by lsp-errors."; LSP expiration.";
      }
      leaf authentication-type-fails sequence {
        type uint32;
        description
                 "Number of authentication type mismatches.";
              }
         "This leaf authentication-fails {
                type uint32;
                description
                 "Number describes the sequence number of authentication key failures."; the LSP.";
      }
      leaf database-overload attributes {
        type uint32; bits {
          bit PARTITIONNED {
            description
                 "Number of times
             "If set, the database has become
                 overloaded."; originator supports partition
              repair.";
          }
              leaf own-lsp-purge
          bit ATTACHED-ERROR {
                type uint32;
            description
                 "Number of times a zero-aged copy of
             "If set, the
                 system's own LSP originator is received from some
                 other node."; attached to
              another area using the referred metric.";
          }
              leaf manual-address-drop-from-area
          bit ATTACHED-EXPENSE {
                type uint32;
            description
                 "Number of times a manual address
                  has been dropped from
             "If set, the area."; originator is attached to
              another area using the referred metric.";
          }
              leaf max-sequence
          bit ATTACHED-DELAY {
                type uint32;
            description
                 "Number of times
             "If set, the system has attempted originator is attached to exceed
              another area using the maximum sequence number."; referred metric.";
          }
              leaf sequence-number-skipped
          bit ATTACHED-DEFAULT {
                type uint32;
            description
                 "Number of times a sequence number skip has
                 occured.";
             "If set, the originator is attached to
              another area using the referred metric.";
          }
              leaf id-len-mismatch
          bit OVERLOAD {
                type uint32;
            description
                 "Number of times a PDU is received with
                  a different value for ID field length
                  from that of
             "If set, the receiving system."; originator is overloaded,
              and must be avoided in path calculation.";
          }
        }
              leaf partition-changes {
                type uint32;
        description
                 "Number
         "This leaf describes attributes of partition changes detected."; the LSP.";
      }
              leaf lsp-errors

      leaf-list ipv4-addresses {
        type uint32; inet:ipv4-address;
        description
                 "Number
          "This leaf describes the IPv4 addresses of LSPs with errors we have
                 received."; the node.
          ISIS reference is TLV 132.";
      }
              leaf spf-runs

      leaf-list ipv6-addresses {
        type uint32; inet:ipv6-address;
        description
                 "Number
         "This leaf describes the IPv6 interface
         addresses of times we ran SPF at this level."; the node.
         ISIS reference is TLV 232.";
      }

      leaf ipv4-te-routerid {
        type inet:ipv4-address;
        description
               "List
          "This leaf describes the IPv4 Traffic Engineering
          router ID of supported levels."; the node.
          ISIS reference is TLV 134.";
      }

      leaf ipv6-te-routerid {
        type inet:ipv6-address;
        description
             "The container defines a list
         "This leaf describes the IPv6 Traffic Engineering
          router ID of counters
              for the IS."; node.
          ISIS reference is TLV 140.";
      }

          container interfaces

      leaf-list protocol-supported {
        type uint8;
        description
         "This leaf describes the list interface {
              key interface; of
         supported protocols.
         ISIS reference is TLV 129.";
      }

      leaf interface dynamic-hostname {
        type string;
        description
         "This leaf describes the name of the interface."; node.
         ISIS reference is TLV 137.";
      }
              uses isis-if-cfg;

      container fast-reroute {
               if-feature fast-reroute;
               uses fast-reroute-if-cfg;
               description
                "IPFRR.";
              }
              uses adjacency-state;

              list topologies authentication {
                key name;
        leaf name authentication-type {
          type leafref {
                      path "../../../../../"
                      +"../../rt:ribs/rt:rib/rt:name";
                  } string;
          description
                    "Name of RIB.";
           "This leaf describes the authentication type
            to be used.";
        }
                uses isis-if-topologies-cfg;
                container fast-reroute
        leaf authentication-key {
                 if-feature fast-reroute;
                 uses fast-reroute-if-cfg;
          type string;
          description
                  "IPFRR.";
           "This leaf describes the authentication key
            to be used. For security reason, the
            authentication key MUST NOT be presented
            in plaintext format. Authors recommends
            to use MD5 hash to present the authentication-key.";
        }
                uses adjacency-state;
        description
                 "List "This container describes authentication
        information of topologies."; the node. ISIS reference is TLV 10.";

      }

      container event-counters mt-entries {
        list topology {

          leaf adjacency-changes MT-ID {
            type uint32; uint16 {
              range "0 .. 4095";
            }
            description
                   "The number
             "This leaf defines the identifier
              of times an adjacency state
                    change has occured on a topology.";
          }

          leaf attributes {
            type bits {
              bit OVERLOAD {
                description
                 "If set, the originator is overloaded,
                  and must be avoided in path
                  calculation.";
              }
              bit ATTACHED {
                description
                 "If set, the originator is attached to
                  another area using the referred metric.";
              }
            }
            description
             "This leaf describes attributes of the LSP
              for the associated topology.";
          }
          description
           "List of topologies supported.";
        }
        description
         "This container describes the topology supported.
         ISIS reference is TLV 229.";
      }

      list router-capabilities {
        leaf flags {
          type bits {
            bit flooding {
              position 0;
              description
               "If the S bit is set(1),
               the IS-IS Router CAPABILITY TLV

              MUST be flooded across the entire routing domain.
              If the S bit is
              not set(0), the TLV MUST NOT be leaked between levels.
              This bit MUST NOT be altered during the TLV leaking.";
            }
            bit down {
              position 1;
              description
              "When the IS-IS Router CAPABILITY TLV is
              leaked from level-2 to level-1, the D bit
              MUST be set.  Otherwise, this interface."; bit MUST
              be clear.  IS-IS Router capability TLVs
              with the D bit set MUST NOT
              be leaked from level-1 to level-2.
              This is to prevent TLV looping.
              ";
            }
          }
          description
           "Flags associated with router capability.";
        }
        container node-tags {
          if-feature node-tag;
          list node-tag {
            leaf tag {
              type uint32;
              description
               "Node tag value.";
            }
            description
             "List of tags.";
          }
          description
           "Container for node tags.";
        }

        leaf binary {
          type binary;
          description
           "This leaf describes the capability of the node.
           Format is binary according to the protocol encoding.";
        }
        description
         "This container describes the capabilities of the node.
         This container may be extended with detailed
         information.
         ISIS reference is TLV 242.";
      }
      container is-neighbor {
        list neighbor {
          uses neighbor;
          description
           "List of neighbors.";
        }
        description
         "This leaf describes list of ISIS neighbors.
         ISIS reference is TLV 2.";
      }

      container extended-is-neighbor {
        list neighbor {
          uses neighbor-extended;
          description
           "List of neighbors.";
        }
        description
         "This container describes list of ISIS extended
         neighbors.
         ISIS reference is TLV 22.";
      }

      container ipv4-internal-reachability {
        list prefixes {
          uses prefix-ipv4-std;
          description
           "List of prefixes.";
        }
        description
         "This container describes list of IPv4 internal
         reachability information.
         ISIS reference is TLV 128.";
      }

      container ipv4-external-reachability {
        list prefixes {
          uses prefix-ipv4-std;
          description
           "List of prefixes.";
        }
        description
         "This container describes list of IPv4 external
         reachability information.
         ISIS reference is TLV 130.";
      }
                leaf adjacency-number

      container extended-ipv4-reachability {
                  type uint32;
        list prefixes {
          uses prefix-ipv4-extended;
          description
                   "The number
           "List of adjacencies on this
                    interface."; prefixes.";
        }
                leaf init-fails {
                  type uint32;
        description
                   "The number of times initialization
         "This container describes list of
                    this interface has failed. This counts
                    events such as PPP NCP failures.
                    Failures to form an adjacency are counted
                    by adjacency-rejects."; IPv4 extended
         reachability information.
         ISIS reference is TLV 135.";
      }

      container mt-is-neighbor {
        list neighbor {
          leaf adjacency-rejects MT-ID {
            type uint32; uint16 {
              range "0 .. 4095";
            }
            description
                   "The number
             "This leaf defines the identifier
              of times an adjacency has been
                    rejected on this interface."; a topology.";
          }
                leaf id-len-mismatch {
                  type uint32;
          uses neighbor-extended;
          description
                   "The number
           "List of times an IS-IS PDU with an ID
                    field length different from that for this
                    system has been received on this interface."; neighbors.";
        }
                leaf max-area-addresses-mismatch {
                  type uint32;
        description
                   "The number
         "This container describes list of times an IS-IS PDU with
                    according max area address field
                    differs from that for
                    this system has been received on this
                    interface."; ISIS multi-topology
          neighbors.
          ISIS reference is TLV 223.";
      }

      container mt-extended-ipv4-reachability {
        list prefixes {
          leaf authentication-type-fails MT-ID {
            type uint32; uint16 {
              range "0 .. 4095";
            }
            description
                   "Number
             "This leaf defines the identifier
              of authentication type mismatches."; a topology.";
          }
                leaf authentication-fails {
                  type uint32;
          uses prefix-ipv4-extended;
          description
                   "Number
           "List of authentication key failures."; prefixes.";

        }
                leaf lan-dis-changes {
                  type uint32;
        description
                   "The number
         "This container describes list of times the DIS has changed
                    on this interface at this level.
                    If the interface type is point to point,
                    the count IPv4
         reachability information in multi-topology
         environment.
         ISIS reference is zero.";
                }
                description
                 "Provides protocol event counters."; TLV 235.";
      }

      container packet-counters mt-ipv6-reachability {
        list level prefixes {
                  key level;
          leaf level MT-ID {
            type level-number; uint16 {
              range "0 .. 4095";
            }
            description
             "This leaf describes defines the ISIS level.";
                  }

                  container iih {
                    leaf in {
                      type uint32;
                      description
                       "Received PDUs."; identifier
              of a topology.";
          }
                    leaf out {
                      type uint32;
          uses prefix-ipv6-extended;
          description
                       "Sent PDUs.";
           "List of prefixes.";
        }
        description
                     "The number
         "This container describes list of IIH PDUs received/sent."; IPv6
         reachability information in multi-topology
         environment.
         ISIS reference is TLV 237.";
      }

      container ish {
                    leaf in ipv6-reachability {
                      type uint32;
                      description
                       "Received PDUs.";
                    }
                    leaf out
        list prefixes {
                      type uint32;
          uses prefix-ipv6-extended;
          description
                       "Sent PDUs.";
           "List of prefixes.";
        }
        description
                     "The number
         "This container describes list of ISH PDUs received/sent."; IPv6
         reachability information.
         ISIS reference is TLV 236.";
      }
    }

    grouping lsdb {
      container esh database {
                    leaf in
        list level-db {
                      type uint32;
                      description
                       "Received PDUs.";
                    }
          key level;

          leaf out level {
            type uint32; level-number;
            description
                       "Sent PDUs.";
             "Current level number";

          }
          list lsp {
            key lsp-id;
            uses lsp-entry;
            description
                     "The number
             "List of ESH PDUs received/sent."; LSPs in LSDB.";
          }
          description
           "This container lsp {
                    leaf describes the list of LSPs
           in {
                      type uint32;
                      description
                       "Received PDUs."; the level x database.";
        }
                    leaf out {
                      type uint32;
        description
                       "Sent PDUs.";
         "This container describes ISIS Link State
          databases.";
      }
      description
                     "The number of LSP PDUs received/sent.";
       "Grouping for LSDB description.";
    }
                  container psnp {
                    leaf in

    /* Augmentations */

    augment "/rt:routing-state/"
      +"rt:ribs/rt:rib/rt:routes/rt:route" {
                      type uint32;
                      description
                       "Received PDUs.";
                    }
                    leaf out
      when "rt:source-protocol = 'isis:isis'" {
                      type uint32;
        description
                       "Sent PDUs."; "ISIS-specific route attributes.";
      }
      uses route-content;
      description
                     "The number of PSNP PDUs received/sent.";
                  }
                  container csnp {
                    leaf
       "This augments route object in {
                      type uint32;
                      description
                       "Received PDUs."; RIB with ISIS-specific
        attributes.";
    }

    augment "/if:interfaces/if:interface" {
      leaf out clns-mtu {
        type uint32; uint16;
        description
                       "Sent PDUs.";
         "Defines CLNS MTU of the interface.";
      }
      description
                     "The number of CSNP PDUs received/sent."; "ISO interface config.";
    }
                  container unknown

    augment "/rt:routing/rt:control-plane-protocols/"
        +"rt:control-plane-protocol" {
                    leaf in
      when "rt:type = 'isis:isis'" {
                      type uint32;
        description
                       "Received PDUs.";
                    }
                    leaf out {
         "This augment is only valid when routing protocol
          instance type uint32;
                      description
                       "Sent PDUs."; is isis.";
      }
      description
                     "The number of unknown PDUs received/sent.";
                  }
       "This augments a routing protocol instance with ISIS
        specific parameters.";
      container isis {
          must "count(area-address) > 0" {
            error-message "At least one area-address
            must be configured.";
            description
                   "List
             "Enforce configuration of supported levels."; at least one area.";
          }

          uses isis-global-cfg;

          container fast-reroute {
           if-feature fast-reroute;
           uses fast-reroute-global-cfg;
           description
                 "Provides packet counters per level.";
                "IPFRR.";
          }
          container spf-control {
              container ietf-spf-delay {
                  if-feature ietf-spf-delay;
                  uses ietf-spf-delay-cfg;
                  description
               "List of interfaces.";
                   "IETF spf delay algorithm configuration.";
              }
              description
             "The container defines operational parameters
              of interfaces.";
               "Container for all SPF computation related
               operations.";
          }
          container spf-log topologies {
              if-feature multi-topology;
              list event topology {
                key id; "name";
                leaf id enable {
                  type uint32; boolean;
                  description
                 "This leaf defines the event identifier.
                  This is a purely internal value.";
                   "Control enabling of topologies";
                }
                leaf spf-type name {
                  type enumeration {
                  enum full leafref {
                    description
                     "Computation done is a Full SPF.";
                     path "../../../../../../rt:ribs/rt:rib/rt:name";
                   }
                  enum route-only {

                  description
                     "Computation done is a
                      reachability computation
                      only.";
                  } "RIB";
                }

                uses isis-global-topologies-cfg;

                description
                 "This leaf describes the type
                  "List of computation
                 used."; topologies";
              }
              leaf level {
                type level-number;
              description
                 "This leaf describes the level affected by the
                 the computation.";
               "Container for multi-topology";
          }
              leaf schedule-timestamp
          container interfaces {
                type yang:timestamp;
                description
                 "This leaf describes the timestamp
                  when the computation was scheduled.";
              }
            list interface {
              key "name";
              leaf start-timestamp name {
                type yang:timestamp; if:interface-ref;

                description
                 "This leaf describes
                 "Reference to the timestamp
                  when interface within
                  the computation was started."; routing-instance.";
            }
              leaf end-timestamp
            uses isis-if-cfg;
            container fast-reroute {
                type yang:timestamp;
              if-feature fast-reroute;
              uses fast-reroute-if-cfg;
              description
                 "This leaf describes the timestamp
                  when the computation was ended.";
                "IPFRR.";
            }
            container topologies {
                if-feature multi-topology;
                list trigger-lsp topology {
                    key "lsp"; name;

                    leaf lsp name {
                      type lsp-id; leafref {
                          path "../../../../../../../../"+
                          "rt:ribs/rt:rib/rt:name";
                      }

                      description
                   "This leaf describes the LSPID
                       "Name of the LSP."; RIB.";
                    }
                leaf sequence {
                  type uint32;
                    uses isis-if-topologies-cfg;
                    description
                   "This leaf describes the sequence
                    number
                     "List of the LSP."; topologies.";
                }
              description
                 "This leaf describes list of LSPs
                  that triggered the computation.";
               "Container for multi-topology";

            }
            description
              "List of computation events."; ISIS interfaces.";
            }
            description
             "This container lists the SPF computation events."; defines ISIS interface specific
             configuration objects.";
         }

         description
          "This container lsp-log {
            list event defines ISIS specific configuration
           objects.";
      }
    }

    augment "/rt:routing-state/"
      +"rt:control-plane-protocols/rt:control-plane-protocol" {
              key id;

              leaf id
      when "rt:type = 'isis:isis'" {
                type uint32;
        description
         "This leaf defines the event identifier.

                  This augment is a purely internal value.";
              }
              leaf level { only valid when routing protocol
          instance type level-number; is isis.";
      }
      description
       "This leaf describes the level affected by the
                 the computation.";
              } augments routing protocol instance states with ISIS
        specific parameters.";

      container lsp isis {
                leaf lsp
        config false;
          uses isis-global-cfg;
          container fast-reroute {

                  type lsp-id;
            if-feature fast-reroute;
            uses fast-reroute-global-cfg;
            uses fast-reroute-global-state;
            description
                   "This leaf describes the LSPID
                    of the LSP.";
             "IPFRR states.";
          }
                leaf sequence
          container spf-control {
                  type uint32;
                  description
                   "This leaf describes the sequence
                    number of the LSP.";
                }
                description
                 "This
              container describes the received LSP
                 , in case of local LSP update the local
                 LSP ID is referenced."; ietf-spf-delay {
                  if-feature ietf-spf-delay;
                  uses ietf-spf-delay-cfg;
                  uses ietf-spf-delay-state;
                  description
                   "IETF spf delay algorithm configuration.";
              }

              leaf received-timestamp {
                type yang:timestamp;
              description
                 "This leaf describes the timestamp
                 when the LSP was received. In case of
                 local LSP update, the timestamp refers
                 to the local LSP update time.";
               "Container for all SPF computation related
               operations.";
          }
          list topologies {
            key name;

            leaf change name {
              type identityref leafref {
                  base lsp-log-reason;
                 path "../../../../../"
                 +"rt:ribs/rt:rib/rt:name";
               }

              description
                 "This leaf describes the type
                "Name of change
                 in the LSP."; RIB.";
            }
            uses local-rib;
            description
             "List of LSP events.";
            }

            description
             "This container lists the LSP reception events.
             Local LSP modification are also contained in the
             list."; topologies.";
          }
          uses local-rib;
          uses system-counters;

          container database interfaces {
            list level-db interface {
              key level; interface;

              leaf level interface {
                type level-number;
                description
                 "Current level number";
              }
              list lsp {
                key lsp-id;

                uses database;
                description
                 "List of LSPs in LSDB.";
              } string;
                description
                 "This container leaf describes the list name
                 of LSPs
               in the level x database.";
            }

            description
             "This container describes ISIS Link State
              databases."; interface.";
              }
              uses isis-if-cfg;
              container hostnames fast-reroute {
               if-feature fast-reroute;
               uses fast-reroute-if-cfg;
               description
                "IPFRR.";
              }
              list hostname topologies {
                key system-id; name;

                leaf system-id name {
                  type system-id; leafref {
                      path "../../../../../"
                      +"../../rt:ribs/rt:rib/rt:name";
                  }
                  description
                 "This leaf describes the system-id
                 associated with the hostname.";
                    "Name of RIB.";
                }
              leaf hostname {

                type string;
                uses isis-if-topologies-cfg;
                uses adjacency-state;

                description
                 "This leaf describes the hostname
                  associated with the system ID.";
                 "List of topologies.";
              }

              uses adjacency-state;
              uses event-counters;
              uses packet-counters;

              description
               "List of system-id/hostname associations"; interfaces.";
            }
            description
             "This
             "The container describes the list defines operational parameters
              of binding between system-id and
             hostnames."; interfaces.";
          }

          uses spf-log;
          uses lsp-log;
          uses hostname-db;
          uses lsdb;

        description
           "This container defines various ISIS states objects.";
      }
    }

    /* RPC methods */

    rpc clear-adjacency {
      description
       "This RPC request clears a particular
        set of ISIS adjacencies. If the operation
        fails for ISIS internal reason, then
        error-tag and error-app-tag should be set
        to a meaningful value.";
      input {

        leaf routing-protocol-instance-name {
          type instance-state-ref;
          mandatory "true";
          description
           "Name of the ISIS protocol instance whose ISIS
            information is being queried.

            If the ISIS instance with name equal to the
            value of this parameter doesn't exist, then this
            operation SHALL fail with error-tag 'data-missing'
            and error-app-tag
            'routing-protocol-instance-not-found'.";
        }
        leaf level {
          type level;
          description
           "ISIS level of the adjacency to be cleared.
           If ISIS level is level-1-2, both level 1 and level 2
           adjacencies would be cleared.

           If the value provided is different from the one
           authorized in the enum type, then this
            operation SHALL fail with error-tag 'data-missing'
            and error-app-tag
            'bad-isis-level'.
           ";
        }
        leaf interface {
          type string;
          description
           "Name of the ISIS interface.

            If the ISIS interface with name equal to the
            value of this parameter doesn't exist, then this
            operation SHALL fail with error-tag 'data-missing'
            and error-app-tag
            'isis-interface-not-found'.";
        }
      }
    }

    rpc clear-database {
      description
       "This RPC request clears a particular
        ISIS database. If the operation
        fails for ISIS internal reason, then
        error-tag and error-app-tag should be set
        to a meaningful value.";
      input {
        leaf routing-protocol-instance-name {
          type instance-state-ref;
          mandatory "true";
          description
           "Name of the ISIS protocol instance whose ISIS
            information is being queried.

            If the ISIS instance with name equal to the
            value of this parameter doesn't exist, then this
            operation SHALL fail with error-tag 'data-missing'
            and error-app-tag
            'routing-protocol-instance-not-found'.";
        }
        leaf level {
          type level;
          description
           "ISIS level of the adjacency to be cleared.
           If ISIS level is level-1-2, both level 1 and level 2
           adjacencies would be cleared.

           If the value provided is different from the one
           authorized in the enum type, then this
            operation SHALL fail with error-tag 'data-missing'
            and error-app-tag
            'bad-isis-level'.
           ";
        }
      }
    }

    /* Notifications */

    notification database-overload {
      uses notification-instance-hdr;

      leaf overload {
        type enumeration {
          enum "off" {
            description
             "The system has left overload condition.";
          }
          enum "on" {
            description
             "The system is in overload condition.";
          }

        }
        description
           "Describes the new overload state of the instance.";
      }
      description
        "This notification is sent when an ISIS instance
         overload condition changes.";
    }
    notification lsp-too-large {
      uses notification-instance-hdr;
      uses notification-interface-hdr;

      leaf pdu-size {
        type uint32;
        description
         "Size of the PDU";
      }
      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      description
        "This notification is sent when we attempt
         to propagate an LSP that is larger than the
         dataLinkBlockSize for the circuit.
         The notification generation must be throttled
         with at least a 5 second gap.
         ";
    }

    notification if-state-change {
      uses notification-instance-hdr;
      uses notification-interface-hdr;

      leaf state {
        type if-state-type;
        description "Interface state.";
      }
      description
        "This notification is sent when an interface
        state change is detected.";
    }

    notification corrupted-lsp-detected {
      uses notification-instance-hdr;
      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      description
        "This notification is sent when we find
         that an LSP that was stored in memory has
         become corrupted.
         ";

    }

    notification attempt-to-exceed-max-sequence {
      uses notification-instance-hdr;
      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      description
        "This notification is sent when the system
        wraps the 32-bit sequence counter of an LSP.
         ";
    }

    notification id-len-mismatch {
      uses notification-instance-hdr;
      uses notification-interface-hdr;

      leaf pdu-field-len {
        type uint8;
        description
         "Size of the ID length in the received PDU";
      }
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      description
        "This notification is sent when we receive a PDU
        with a different value for the System ID length.
        The notification generation must be throttled
        with at least a 5 second gap.
         ";
    }

    notification max-area-addresses-mismatch {
      uses notification-instance-hdr;
      uses notification-interface-hdr;

      leaf max-area-addresses {
        type uint8;
        description
         "Received number of supported areas";
      }
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      description
        "This notification is sent when we receive a PDU
        with a different value for the Maximum Area Addresses.
        The notification generation must be throttled
        with at least a 5 second gap.
         ";
    }

    notification own-lsp-purge {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      description
        "This notification is sent when the system
        receives a PDU with its own system ID and zero age.
         ";
    }

    notification sequence-number-skipped {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      description
        "This notification is sent when the system
        receives a PDU with its own system ID and
        different contents. The system has to reissue
        the LSP with a higher sequence number.
         ";
    }

    notification authentication-type-failure {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";

      }
      description
        "This notification is sent when the system
        receives a PDU with the wrong authentication type
        field.
        The notification generation must be throttled with
        at least a 5 second gap.
         ";
    }

    notification authentication-failure {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      description
        "This notification is sent when the system
        receives a PDU with the wrong authentication
        information.
        The notification generation must be throttled with
        at least a 5 second gap.
         ";
    }

    notification version-skew {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf protocol-version {
        type uint8;
        description
         "Protocol version received in the PDU.";
      }
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      description
        "This notification is sent when the system
        receives a PDU with a different protocol version
        number.
        The notification generation must be throttled with at least
         a 5 second gap.
         ";
    }
    notification area-mismatch {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      description
        "This notification is sent when the system
        receives a Hello PDU from an IS that does
        not share any area address.
        The notification generation must be throttled with at least
         a 5 second gap.
         ";
    }

    notification rejected-adjacency {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      leaf reason {
        type string;
        description
         "The system may provide a reason to reject the
          adjacency. If the reason is not available,
          the system use an empty string.";
      }
      description
        "This notification is sent when the system
        receives a Hello PDU from an IS but does not
        establish an adjacency for some reason.
        The notification generation must be throttled with at least
         a 5 second gap.
         ";
    }

    notification protocols-supported-mismatch {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      leaf-list protocols {
        type uint8;
        description
         "The list of protocols supported by the
          remote system.";
      }
      description
        "This notification is sent when the system
        receives a non pseudonode LSP that has no matching
        protocol supported.
        The notification generation must be throttled with at least
         a 5 second gap.
         ";
    }

    notification lsp-error-detected {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      leaf raw-pdu {
        type binary;
        description
         "Received raw PDU.";
      }
      leaf error-offset {
        type uint32;
        description
         "If the problem is a malformed TLV,
         the error-offset points to the start of the TLV.
         If the problem is with the LSP header,
         the error-offset points to the suspicious byte";
      }
      leaf tlv-type {
        type uint8;
        description
         "if the problem is a malformed TLV, the tlv-type is set
         to the type value of the suspicious TLV.
         Otherwise this leaf is not present.";
      }
      description
        "This notification is sent when the system
        receives a  LSP with a parse error.

        The notification generation must be throttled with at least
         a 5 second gap.
         ";
    }

    notification adjacency-state-change {
      uses notification-instance-hdr;
      uses notification-interface-hdr;
      leaf neighbor {
        type string;
        description
         "Describes the name of the neighbor. If the
         name of the neighbor is not available, the
         field would be empty.";
      }
      leaf neighbor-system-id {
        type system-id;
        description
         "Describes the system-id of the neighbor.";
      }
      leaf state {
        type adj-state-type;

        description
         "This leaf describes the new state of the
          ISIS adjacency.";
      }
      leaf reason {
        type string;
        description
         "If the adjacency is going to DOWN,
         this leaf provides a reason for the adjacency
         going down. The reason is provided as a text.
         If the adjacency is going to UP, no reason is
         provided.";
      }
      description
        "This notification is sent when an ISIS adjacency
         moves to Up state or to Down state.";
    }

    notification lsp-received {
      uses notification-instance-hdr;
      uses notification-interface-hdr;

      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      leaf sequence {
        type uint32;
        description
         "Sequence number of the received LSP.";
      }
      leaf received-timestamp {
        type yang:timestamp;

        description
         "This leaf describes the timestamp
         when the LSP was received. ";
      }
      leaf neighbor-system-id {
        type system-id;
        description
         "Describes the system-id of the neighbor
         that sent the LSP.";
      }
      description
        "This notification is sent when a LSP
        is received.
        The notification generation must be throttled with at least
         a 5 second gap. ";
    }

    notification lsp-generation {
      uses notification-instance-hdr;

      leaf lsp-id {
        type lsp-id;
        description
         "LSP ID.";
      }
      leaf sequence {
        type uint32;
        description
         "Sequence number of the received LSP.";
      }
      leaf send-timestamp {
        type yang:timestamp;

        description
         "This leaf describes the timestamp
         when our LSP was regenerated. ";
      }
      description
        "This notification is sent when a LSP
        is regenerated.
        The notification generation must be throttled with at least
         a 5 second gap. ";
    }
  }

  <CODE ENDS>

7.  Security Considerations

   Configuration and state data defined in this document are designed to
   be accessed via the NETCONF protocol [RFC6241].

   As IS-IS is an IGP protocol (critical piece of the network), ensuring
   stability and security of the protocol is mandatory for the network
   service.

   Authors recommends to implement NETCONF access control model
   ([RFC6536]) to restrict access to all or part of the configuration to
   specific users.  Access control to RPCs is also critical as RPC
   allows to clear protocol datastructures that would definitively
   impact the network service.  This kind of RPC needs only to be used
   in specific cases by well-known experienced users.

   Authors consider that all the configuration is considered as
   sensitive/vulnerable as well as RPCs.  But security teams can decide
   to open some part of the configuration to less experienced users
   depending on the internal organization, for example:

   o  User FullWrite: would access to the whole data model.  This kind
      of profile may be restricted to few experienced people.

   o  User PartialWrite: would only access to configuration part within
      /isis/interfaces/interface.  So this kind of profile is restricted
      to creation/modification/deletion of interfaces.  This profile
      does not have access to RPC.

   o  User Read: would only access to the operational states.

   Unauthorized access to configuration or RPC may cause high damages to
   the network service.

   The "isis/database" may contain authentication information.  As
   presented in the description of the "/isis/database/level-
   1/lsp/authentication/authentication-key", the authentication MUST
   never be displayed in a plaintext format for security reason.

   Authors recommend the usage of MD5 to display or return the
   authentication-key.

   Some authentication-key may also be required in the "isis" writable
   container.  When configuring IS-IS using the NETCONF protocol,
   authors recommends the usage of secure transport of NETCONF using SSH
   ([RFC6242]).

8.  Contributors

   Authors would like to thank Kiran Agrahara Sreenivasa, Dean
   Bogdanovic, Yingzhen Qu, Yi Yang for their major contributions to the
   draft.

9.  Acknowledgements

   TBD.

10.  IANA Considerations

   The IANA is requested to assign two new URIs from the IETF XML
   registry ([RFC3688]).  Authors are suggesting the following URI:

       URI: urn:ietf:params:xml:ns:yang:ietf-isis
       Registrant Contact: IS-IS WG
       XML: N/A, the requested URI is an XML namespace

   This document also requests one new YANG module name in the YANG
   Module Names registry ([RFC6020]) with the following suggestion:

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

11.  Change log for ietf-isis YANG module

11.1.  From version -16 to version -17

   o  Cosmetic fixes.

   o  Use of rt-types model.

11.2.  From version -15 to version -16

   o  Alignment with last IETF key chain model.

   o  lsp-log "change" leaf moved as an identity.

   o  Incremental SPF removed from spf-log types.

11.2.

11.3.  From version -14 to version -15

   o  Alignment with OSPF model done:

      *  Added spf-control container with IETF SPF delay algorithm as a
         feature.

      *  Added graceful-restart options.

      *  Added nsr as a feature.

      *  Removed per topology FRR.  Need to be augmented if necessary.

      *  Created an ldp container within mpls.

      *  Renamed igp-ldp-sync to igp-sync.

      *  Added auto-cost container.

      *  Moved reference-bandwidth under auto-cost container.

      *  Added IS-IS local RIB as operational state.

      *  Added decode-completed and raw-data leaves in the LSDB model.

      *  Modified the notification header.

11.3.

11.4.  From version -13 to version -14

   o  Segment Routing extensions are now in a separate document.

11.4.

11.5.  From version -12 to version -13

   o  Move feature nlpid-control to container rather than list.

   o  Rename multi-topology to topologies to align with OSPF.

   o  Rename bfd/enabled to bfd/enable for consistency reason.

   o  Add support for NSR with a feature.

11.5.

11.6.  From version -09 to version -12

   o  Rename node-tag container to node-tags.

11.6.

11.7.  From version -08 to version -09

   o  Added container before af list.

   o  Added container before topology list.

   o  Aligned LFA if per level cfg.

   o  Align to draft-ietf-netmod-routing-cfg-23.

11.7.

11.8.  From version -07 to version -08

   o  Remove selector from system-id type.

   o  Add some default values.

   o  Moved lists to containers+groupings for per level configuration.

   o  remove routing-instance as per core routing model v21.

   o  added BFD leaf (no more BFD protocol model).

   o  changed keychain module reference.

11.8.

11.9.  From version -05 to version -07

   o  Move Overload config from list to container.

   o  Move Overload-max-metric config from list to container.

   o  Move preference config from list to container.

   o  Add Node flag in config.

   o  Removed BFD config => moved to isis-bfd module.

   o  Remove call to routing policy model.

11.9.

11.10.  From version -03 to version -05

   o  Correct invalid references to previous versions of core routing
      model.

   o  Remove BFD config and replace by groupings from ietf-bfd.

   o  Adding routing-policy support through routing-policy model.

11.10.

11.11.  From version -02 to version -03

   o  Reviewed config and op state groupings.

   o  Add default value to lfa candidate-disabled.

   o  Add enable leaf to isis container to reflect admin state.

   o  Move to VRF centric only.

   o  Segment routing is part os a separate module.

11.11.

11.12.  From version -01 to version -02

   o  Adding IPFRR.

   o  Adding igp-ldp-sync.

   o  Adding segment-routing.

   o  Adding instance reference to operational states.

   o  Move AF type from string to identity.

   o  Updated router-capability in LSDB description.

   o  packet counters moved to interface-packet-counters.

   o  Added modification information in lsp-log.

   o  Removing igp-ldp-sync timer in IS-IS.

   o  Defining hierarchy for operational states.

   o  Adding clns-mtu.

   o  Adding key-chain.

11.12.

11.13.  From version -00 to version -01

   o  Interface metric move from af container to interface container.

   o  Hello-padding on interface moved to hello-padding-disable with
      empty type.

   o  three-way-handshake removed.

   o  route preference changed to a choice.

   o  csnp-authentication/psnp-authentication merged to authentication
      container.

   o  lsp-gen-interval-exp-delay removed.

   o  Added overload-max-metric feature.

   o  overload-max-metric is in a separate container.

   o  Change hello-padding to container.

   o  Change bfd to container.

   o  Make BFD a feature.

   o  Create mpls-te container and put router-id inside.

   o  Remove GR helper disable and timers.

12.  Normative References

   [I-D.ietf-netmod-routing-cfg]
              Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
              Management", draft-ietf-netmod-routing-cfg-25 (work in
              progress), November 2016.

   [I-D.ietf-rtgwg-yang-key-chain]
              Lindem, A., Qu, Y., Yeung, D., Chen, I., and Z. Zhang,
              "Routing Key Chain YANG Data Model", draft-ietf-rtgwg-
              yang-key-chain-17 (work in progress), March 2017.

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

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

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

   [RFC5286]  Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
              IP Fast Reroute: Loop-Free Alternates", RFC 5286, DOI
              10.17487/RFC5286, September 2008,
              <http://www.rfc-editor.org/info/rfc5286>.

   [RFC5443]  Jork, M., Atlas, A., and L. Fang, "LDP IGP
              Synchronization", RFC 5443, DOI 10.17487/RFC5443, March
              2009, <http://www.rfc-editor.org/info/rfc5443>.

   [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>.

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

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

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536, DOI
              10.17487/RFC6536, March 2012,
              <http://www.rfc-editor.org/info/rfc6536>.

   [RFC7490]  Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N.
              So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)",
              RFC 7490, DOI 10.17487/RFC7490, April 2015,
              <http://www.rfc-editor.org/info/rfc7490>.

Appendix A.  Example of IS-IS configuration in XML

   This section gives an example of configuration of an IS-IS instance
   on a device.  The example is written in XML.

   <?xml version="1.0" encoding="utf-8"?>
   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
         <name>SLI</name>
         <router-id>1.1.1.1</router-id>
         <description/>
         <interfaces>
           <interface>
             <name>Loopback0</name>
           </interface>
           <interface>
             <name>Eth1</name>
           </interface>
         </interfaces>
         <control-plane-protocols>
           <control-plane-protocol>
             <name>ISIS</name>
             <description/>
             <type>isis:isis</type>
             <isis xmlns="urn:ietf:params:xml:ns:yang:ietf-isis">
                 <enable>true</enable>
                 <level-type>level-2</level-type>
                 <system-id>87FC.FCDF.4432</system-id>
                 <area-address>49.0001</area-address>
                 <mpls-te>
                   <ipv4-router-id>1.1.1.1</ipv4-router-id>
                 </mpls-te>
                 <lsp-lifetime>65535</lsp-lifetime>
                 <lsp-refresh>65000</lsp-refresh>
                 <metric-type>
                   <value>wide</value>
                 </metric-type>
                 <default-metric>
                   <value>111111</value>
                 </default-metric>
                 <afs>
                   <af>
                       <af>ipv4-unicast</af>
                       <enabled>true</enabled>
                   </af>
                 </afs>
                 <interfaces>
                   <interface>
                     <name>Loopback0</name>
                     <tag>200</tag>
                     <metric>
                       <value>0</value>
                     </metric>
                     <passive>true</passive>
                   </interface>
                   <interface>
                     <name>Eth1</name>
                     <level-type>level-2</level-type>
                     <interface-type>point-to-point</interface-type>
                     <metric>
                       <value>167890</value>
                     </metric>
                   </interface>

                 </interfaces>
             </isis>
           </control-plane-protocol>
         </control-plane-protocols>
     </routing>
     <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
       <interface>
         <name>Loopback0</name>
         <description/>
         <type/>
         <link-up-down-trap-enable/>
         <ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
           <mtu/>
           <address>
             <ip>1.1.1.1</ip>
             <prefix-length>32</prefix-length>
           </address>
         </ipv4>

       </interface>
       <interface>
         <name>Eth1</name>
         <description/>
         <type/>
         <link-up-down-trap-enable/>
         <ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
           <mtu/>
           <address>
             <ip>10.0.0.1</ip>
             <prefix-length>30</prefix-length>
           </address>
         </ipv4>

       </interface>
     </interfaces>
   </data>

Authors' Addresses

   Stephane Litkowski
   Orange

   Email: stephane.litkowski@orange.com
   Derek Yeung
   Arrcus, Inc

   Email: derek@arrcus.com

   Acee Lindem
   Cisco Systems

   Email: acee@cisco.com

   Jeffrey Zhang
   Juniper Networks

   Email: zzhang@juniper.net

   Ladislav Lhotka
   CZ.NIC

   Email: lhotka@nic.cz