module ietf-ospf {

    yang-version 1.1;

    namespace
      "urn:ietf:params:xml:ns:yang:ietf-ospf";

    prefix ospf;

    import ietf-inet-types {
      prefix inet;
      reference
        "RFC 6991: Common YANG Data Types";


    }
    import ietf-yang-types {
      prefix yang;
      reference
        "RFC 6991: Common YANG Data Types";


    }
    import ietf-interfaces {
      prefix if;
      reference
        "RFC 8343: A YANG Data Model for Interface Management";


    }
    import ietf-routing-types {
      prefix rt-types;
      reference
        "RFC 8294: Common YANG Data Types for the Routing Area";


    }
    import iana-routing-types {
      prefix iana-rt-types;
      reference
        "RFC 8294: Common YANG Data Types for the Routing Area";


    }
    import ietf-routing {
      prefix rt;
      reference
        "RFC 8349: A YANG Data Model for Routing Management
        (NMDA Version)";


    }
    import ietf-key-chain {
      prefix key-chain;
      reference
        "RFC 8177: YANG Data Model for Key Chains";


    }
    import ietf-bfd-types {
      prefix bfd-types;
      reference
        "RFC 9314: YANG Data Model for Bidirectional Forwarding
        Detection (BFD)";


    }

    organization
      "IETF Link State Routing (lsr) Working Group";

    contact
      "WG Web:   <https://datatracker.ietf.org/wg/lsr/>
WG List:  <mailto:lsr@ietf.org>

Editor:   Derek Yeung
	  <mailto:derek@arrcus.com>
Author:   Acee Lindem
	  <mailto:acee@cisco.com>
Author:   Yingzhen Qu
	  <mailto:yingzhen.qu@futurewei.com>
Author:   Jeffrey Zhang
	  <mailto:zzhang@juniper.net>
Author:   Ing-Wher Chen
	  <mailto:ingwherchen@mitre.org>";

    description
      "This YANG module defines the generic configuration and
operational state for the OSPF protocol common to all
vendor implementations.  It is intended that the module
will be extended by vendors to define vendor-specific
OSPF configuration parameters and policies --
for example, route maps or route policies.

This YANG data model conforms to the Network Management
Datastore Architecture (NMDA) as described in RFC 8342.

The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.

Copyright (c) 2022 IETF Trust and the persons identified as
authors of the code.  All rights reserved.

Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to
the license terms contained in, the Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).

This version of this YANG module is part of RFC 9129; see the
RFC itself for full legal notices.";

    revision "2022-10-19" {
      description "Initial revision.";
      reference
        "RFC 9129: YANG Data Model for the OSPF Protocol";

    }


    feature multi-topology {
      description
        "Support for Multi-Topology (MT) routing.";
      reference
        "RFC 4915: Multi-Topology (MT) Routing in OSPF";

    }

    feature multi-area-adj {
      description
        "Support for OSPF multi-area adjacencies as described in
RFC 5185.";
      reference
        "RFC 5185: OSPF Multi-Area Adjacency";

    }

    feature explicit-router-id {
      description
        "Sets the Router ID per instance explicitly.";
    }

    feature demand-circuit {
      description
        "Support for OSPF demand circuits as defined in RFC 1793.";
      reference
        "RFC 1793: Extending OSPF to Support Demand Circuits";

    }

    feature mtu-ignore {
      description
        "Disable OSPF Database Description packet MTU
mismatch checking as specified in the OSPFv2
protocol specification (RFC 2328).  This mismatch checking
also applies to OSPFv3 (RFC 5340).";
      reference
        "RFC 2328: OSPF Version 2, Section 10.6
         RFC 5340: OSPF for IPv6";

    }

    feature lls {
      description
        "OSPF link-local signaling (LLS) as defined in RFC 5613.";
      reference
        "RFC 5613: OSPF Link-Local Signaling";

    }

    feature prefix-suppression {
      description
        "OSPF prefix suppression support as described in RFC 6860.";
      reference
        "RFC 6860: Hiding Transit-Only Networks in OSPF";

    }

    feature ttl-security {
      description
        "Support for OSPF Time to Live (TTL) security checking.";
      reference
        "RFC 5082: The Generalized TTL Security Mechanism (GTSM)";

    }

    feature nsr {
      description
        "Non-Stop-Routing (NSR) support.  The OSPF NSR feature
allows a router with redundant control-plane capability
(e.g., dual Route Processor (RP) cards) to maintain its
state and adjacencies during planned and unplanned
OSPF instance restarts.  It differs from graceful restart
or Non-Stop Forwarding (NSF) in that no protocol signaling
or assistance from adjacent OSPF neighbors is required to
recover control-plane state.";
    }

    feature graceful-restart {
      description
        "Graceful OSPF restart as defined in RFCs 3623 and 5187.";
      reference
        "RFC 3623: Graceful OSPF Restart
         RFC 5187: OSPFv3 Graceful Restart";

    }

    feature auto-cost {
      description
        "Calculates the OSPF interface cost according to
reference bandwidth.";
      reference
        "RFC 2328: OSPF Version 2";

    }

    feature max-ecmp {
      description
        "Sets the maximum number of ECMP paths.";
    }

    feature max-lsa {
      description
        "Sets the maximum number of Link State Advertisements (LSAs)
the OSPF instance will accept.";
      reference
        "RFC 1765: OSPF Database Overflow";

    }

    feature te-rid {
      description
        "Support for configuration of the Traffic Engineering (TE)
Router ID, i.e., the Router Address TLV as described in
Section 2.4.1 of RFC 3630 or the Router IPv6 Address TLV
as described in Section 3 of RFC 5329.";
      reference
        "RFC 3630: Traffic Engineering (TE) Extensions to
        OSPF Version 2, Section 2.4.1
         RFC 5329: Traffic Engineering Extensions to OSPF Version 3,
        Section 3";

    }

    feature ldp-igp-sync {
      description "LDP IGP synchronization.";
      reference
        "RFC 5443: LDP IGP Synchronization";

    }

    feature ospfv2-authentication-trailer {
      description
        "Support for the OSPFv2 authentication trailer.";
      reference
        "RFC 5709: OSPFv2 HMAC-SHA Cryptographic Authentication
         RFC 7474: Security Extension for OSPFv2 When
        Using Manual Key Management";

    }

    feature ospfv3-authentication-ipsec {
      description
        "Support for IPsec for OSPFv3 authentication.";
      reference
        "RFC 4552: Authentication/Confidentiality for OSPFv3";

    }

    feature ospfv3-authentication-trailer {
      description
        "Support for the OSPFv3 authentication trailer.";
      reference
        "RFC 7166: Supporting Authentication Trailer for OSPFv3";

    }

    feature fast-reroute {
      description
        "Support for IP Fast Reroute (IP-FRR).";
      reference
        "RFC 5714: IP Fast Reroute Framework";

    }

    feature key-chain {
      description
        "Support of key chains for authentication.";
      reference
        "RFC 8177: YANG Data Model for Key Chains";

    }

    feature node-flag {
      description
        "Support for node flags for OSPF prefixes.";
      reference
        "RFC 7684: OSPFv2 Prefix/Link Attribute Advertisement";

    }

    feature node-tag {
      description
        "Support for node administrative tags for OSPF routing
instances.";
      reference
        "RFC 7777: Advertising Node Administrative Tags in OSPF";

    }

    feature lfa {
      description
        "Support for Loop-Free Alternates (LFAs).";
      reference
        "RFC 5286: Basic Specification for IP Fast Reroute:
        Loop-Free Alternates";

    }

    feature remote-lfa {
      description
        "Support for Remote LFAs (R-LFAs).";
      reference
        "RFC 7490: Remote Loop-Free Alternate (LFA) Fast Reroute
        (FRR)";

    }

    feature stub-router {
      description
        "Support for OSPF stub router advertisement as defined in
RFC 6987.";
      reference
        "RFC 6987: OSPF Stub Router Advertisement";

    }

    feature pe-ce-protocol {
      description
        "Support for OSPF as a Provider Edge to Customer Edge (PE-CE)
protocol.";
      reference
        "RFC 4577: OSPF as the Provider/Customer Edge Protocol
        for BGP/MPLS IP Virtual Private Networks (VPNs)
         RFC 6565: OSPFv3 as a Provider Edge to Customer Edge (PE-CE)
        Routing Protocol";

    }

    feature ietf-spf-delay {
      description
        "Support for the IETF Shortest Path First (SPF) delay
algorithm.";
      reference
        "RFC 8405: Shortest Path First (SPF) Back-Off Delay Algorithm
        for Link-State IGPs";

    }

    feature bfd {
      description
        "Support for BFD to detect OSPF neighbor reachability.";
      reference
        "RFC 5880: Bidirectional Forwarding Detection (BFD)
         RFC 5881: Bidirectional Forwarding Detection
        (BFD) for IPv4 and IPv6 (Single Hop)";

    }

    feature hybrid-interface {
      description
        "Support for the OSPF hybrid interface type.";
      reference
        "RFC 6845: OSPF Hybrid Broadcast and
        Point-to-Multipoint Interface Type";

    }

    identity ospf {
      base rt:routing-protocol;
      description
        "Any OSPF protocol version.";
    }

    identity ospfv2 {
      base ospf;
      description "OSPFv2 protocol.";
    }

    identity ospfv3 {
      base ospf;
      description "OSPFv3 protocol.";
    }

    identity area-type {
      description
        "Base identity for an OSPF area type.";
    }

    identity normal-area {
      base area-type;
      description "OSPF normal area.";
    }

    identity stub-nssa-area {
      base area-type;
      description
        "OSPF stub area or Not-So-Stubby Area (NSSA).";
    }

    identity stub-area {
      base stub-nssa-area;
      description "OSPF stub area.";
    }

    identity nssa-area {
      base stub-nssa-area;
      description "OSPF NSSA.";
      reference
        "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option";

    }

    identity ospf-lsa-type {
      description
        "Base identity for OSPFv2 and OSPFv3
Link State Advertisement (LSA) types.";
    }

    identity ospfv2-lsa-type {
      base ospf-lsa-type;
      description "OSPFv2 LSA types.";
    }

    identity ospfv2-router-lsa {
      base ospfv2-lsa-type;
      description
        "OSPFv2 Router-LSA - Type 1.";
    }

    identity ospfv2-network-lsa {
      base ospfv2-lsa-type;
      description
        "OSPFv2 Network-LSA - Type 2.";
    }

    identity ospfv2-summary-lsa-type {
      base ospfv2-lsa-type;
      description
        "OSPFv2 summary LSA types.";
    }

    identity ospfv2-network-summary-lsa {
      base ospfv2-summary-lsa-type;
      description
        "OSPFv2 Network summary LSA - Type 3.";
    }

    identity ospfv2-asbr-summary-lsa {
      base ospfv2-summary-lsa-type;
      description
        "OSPFv2 Autonomous System Boundary Router (ASBR) summary LSA -
Type 4.";
    }

    identity ospfv2-external-lsa-type {
      base ospfv2-lsa-type;
      description
        "OSPFv2 External-LSA types.";
    }

    identity ospfv2-as-external-lsa {
      base ospfv2-external-lsa-type;
      description
        "OSPFv2 AS-External-LSA - Type 5.";
    }

    identity ospfv2-nssa-lsa {
      base ospfv2-external-lsa-type;
      description
        "OSPFv2 NSSA-LSA - Type 7.";
    }

    identity ospfv2-opaque-lsa-type {
      base ospfv2-lsa-type;
      description "OSPFv2 Opaque-LSA types.";
      reference
        "RFC 5250: The OSPF Opaque LSA Option";

    }

    identity ospfv2-link-scope-opaque-lsa {
      base ospfv2-opaque-lsa-type;
      description
        "OSPFv2 Link-Scope Opaque-LSA - Type 9.";
    }

    identity ospfv2-area-scope-opaque-lsa {
      base ospfv2-opaque-lsa-type;
      description
        "OSPFv2 Area-Scope Opaque-LSA - Type 10.";
    }

    identity ospfv2-as-scope-opaque-lsa {
      base ospfv2-opaque-lsa-type;
      description
        "OSPFv2 AS-Scope Opaque-LSA - Type 11.";
    }

    identity ospfv2-unknown-lsa-type {
      base ospfv2-lsa-type;
      description "OSPFv2 unknown LSA type.";
    }

    identity ospfv3-lsa-type {
      base ospf-lsa-type;
      description "OSPFv3 LSA types.";
      reference
        "RFC 5340: OSPF for IPv6";

    }

    identity ospfv3-router-lsa {
      base ospfv3-lsa-type;
      description
        "OSPFv3 Router-LSA - Type 0x2001.";
    }

    identity ospfv3-network-lsa {
      base ospfv3-lsa-type;
      description
        "OSPFv3 Network-LSA - Type 0x2002.";
    }

    identity ospfv3-summary-lsa-type {
      base ospfv3-lsa-type;
      description
        "OSPFv3 summary LSA types.";
    }

    identity ospfv3-inter-area-prefix-lsa {
      base ospfv3-summary-lsa-type;
      description
        "OSPFv3 Inter-Area-Prefix-LSA - Type 0x2003.";
    }

    identity ospfv3-inter-area-router-lsa {
      base ospfv3-summary-lsa-type;
      description
        "OSPFv3 Inter-Area-Router-LSA - Type 0x2004.";
    }

    identity ospfv3-external-lsa-type {
      base ospfv3-lsa-type;
      description
        "OSPFv3 External-LSA types.";
    }

    identity ospfv3-as-external-lsa {
      base ospfv3-external-lsa-type;
      description
        "OSPFv3 AS-External-LSA - Type 0x4005.";
    }

    identity ospfv3-nssa-lsa {
      base ospfv3-external-lsa-type;
      description
        "OSPFv3 NSSA-LSA - Type 0x2007.";
    }

    identity ospfv3-link-lsa {
      base ospfv3-lsa-type;
      description
        "OSPFv3 Link-LSA - Type 0x0008.";
    }

    identity ospfv3-intra-area-prefix-lsa {
      base ospfv3-lsa-type;
      description
        "OSPFv3 Intra-Area-Prefix-LSA - Type 0x2009.";
    }

    identity ospfv3-router-information-lsa {
      base ospfv3-lsa-type;
      description
        "OSPFv3 Router-Information-LSA - Types 0x800C,
0xA00C, and 0xC00C.";
    }

    identity ospfv3-unknown-lsa-type {
      base ospfv3-lsa-type;
      description "OSPFv3 unknown LSA type.";
    }

    identity lsa-log-reason {
      description
        "Base identity for an LSA log reason.";
    }

    identity lsa-refresh {
      base lsa-log-reason;
      description
        "Identity used when an LSA is logged
as a result of receiving a refresh LSA.";
    }

    identity lsa-content-change {
      base lsa-log-reason;
      description
        "Identity used when an LSA is logged
as a result of a change in the contents
of the LSA.";
    }

    identity lsa-purge {
      base lsa-log-reason;
      description
        "Identity used when an LSA is logged
as a result of being purged.";
    }

    identity informational-capability {
      description
        "Base identity for router informational capabilities.";
    }

    identity graceful-restart {
      base informational-capability;
      description
        "When set, the router is capable of restarting
gracefully.";
      reference
        "RFC 3623: Graceful OSPF Restart
         RFC 5187: OSPFv3 Graceful Restart";

    }

    identity graceful-restart-helper {
      base informational-capability;
      description
        "When set, the router is capable of acting as
a graceful restart helper.";
      reference
        "RFC 3623: Graceful OSPF Restart
         RFC 5187: OSPFv3 Graceful Restart";

    }

    identity stub-router {
      base informational-capability;
      description
        "When set, the router is capable of acting as
an OSPF stub router.";
      reference
        "RFC 6987: OSPF Stub Router Advertisement";

    }

    identity traffic-engineering {
      base informational-capability;
      description
        "When set, the router is capable of OSPF TE.";
      reference
        "RFC 3630: Traffic Engineering (TE) Extensions to
        OSPF Version 2
         RFC 5329: Traffic Engineering Extensions to OSPF Version 3";

    }

    identity p2p-over-lan {
      base informational-capability;
      description
        "When set, the router is capable of OSPF point-to-point
over a LAN.";
      reference
        "RFC 5309: Point-to-Point Operation over LAN in Link State
        Routing Protocols";

    }

    identity experimental-te {
      base informational-capability;
      description
        "When set, the router is capable of OSPF experimental TE.";
      reference
        "RFC 4973: OSPF-xTE: Experimental Extension to OSPF for
        Traffic Engineering";

    }

    identity router-lsa-bit {
      description
        "Base identity for Router-LSA bits.";
    }

    identity vlink-end-bit {
      base router-lsa-bit;
      description
        "V-bit.  When set, the router is an endpoint of one or
more virtual links.";
    }

    identity asbr-bit {
      base router-lsa-bit;
      description
        "E-bit.  When set, the router is an Autonomous System
Boundary Router (ASBR).";
    }

    identity abr-bit {
      base router-lsa-bit;
      description
        "B-bit.  When set, the router is an Area Border
Router (ABR).";
    }

    identity nssa-bit {
      base router-lsa-bit;
      description
        "Nt-bit.  When set, the router is an NSSA border router
that is unconditionally translating NSSA-LSAs into
AS-External-LSAs.";
    }

    identity ospfv3-lsa-option {
      description
        "Base identity for OSPF LSA Options.";
    }

    identity af-bit {
      base ospfv3-lsa-option;
      description
        "AF-bit.  When set, the router supports OSPFv3 Address
Families (AFs) as described in RFC 5838.";
      reference
        "RFC 5838: Support of Address Families in OSPFv3";

    }

    identity dc-bit {
      base ospfv3-lsa-option;
      description
        "DC-bit.  When set, the router supports demand circuits.";
    }

    identity r-bit {
      base ospfv3-lsa-option;
      description
        "R-bit.  When set, the originator is an active router.";
    }

    identity n-bit {
      base ospfv3-lsa-option;
      description
        "N-bit.  When set, the router is attached to an NSSA.";
    }

    identity e-bit {
      base ospfv3-lsa-option;
      description
        "E-bit.  This bit describes the way AS-External-LSAs
are flooded.";
    }

    identity v6-bit {
      base ospfv3-lsa-option;
      description
        "V6-bit.  If clear, the router/link should be excluded
from IPv6 routing calculations.";
    }

    identity ospfv3-prefix-option {
      description
        "Base identity for OSPFv3 prefix options.";
    }

    identity nu-bit {
      base ospfv3-prefix-option;
      description
        "NU-bit.  When set, the prefix should be excluded
from IPv6 unicast calculations.";
    }

    identity la-bit {
      base ospfv3-prefix-option;
      description
        "LA-bit.  When set, the prefix is actually an IPv6
interface address of the advertising router.";
    }

    identity p-bit {
      base ospfv3-prefix-option;
      description
        "P-bit.  When set, the NSSA prefix should be
translated to an AS-External-LSA and advertised
by the translating NSSA border router.";
    }

    identity dn-bit {
      base ospfv3-prefix-option;
      description
        "DN-bit.  When set, the Inter-Area-Prefix-LSA or
AS-External-LSA prefix has been advertised as an
L3VPN prefix.";
    }

    identity ospfv2-lsa-option {
      description
        "Base identity for OSPFv2 LSA Options.";
    }

    identity mt-bit {
      base ospfv2-lsa-option;
      description
        "MT-bit.  When set, the router supports multi-topology as
described in RFC 4915.";
      reference
        "RFC 4915: Multi-Topology (MT) Routing in OSPF";

    }

    identity v2-dc-bit {
      base ospfv2-lsa-option;
      description
        "DC-bit.  When set, the router supports demand circuits.";
    }

    identity v2-p-bit {
      base ospfv2-lsa-option;
      description
        "P-bit.  Only used in type-7 LSAs.  When set, an NSSA
border router should translate the type-7 LSA
to a type-5 LSA.";
    }

    identity mc-bit {
      base ospfv2-lsa-option;
      description
        "MC-bit.  When set, the router supports
Multicast Extensions to OSPF (MOSPF).";
    }

    identity v2-e-bit {
      base ospfv2-lsa-option;
      description
        "E-bit.  This bit describes the way AS-External-LSAs
are flooded.";
    }

    identity o-bit {
      base ospfv2-lsa-option;
      description
        "O-bit.  When set, the router is opaque capable as described
in RFC 5250.";
      reference
        "RFC 5250: The OSPF Opaque LSA Option";

    }

    identity v2-dn-bit {
      base ospfv2-lsa-option;
      description
        "DN-bit.  When a type 3, type 5, or type 7 LSA is sent from a
PE to a CE, the DN-bit must be set.  See RFC 4576.";
      reference
        "RFC 4576: Using a Link State Advertisement (LSA) Options Bit
        to Prevent Looping in BGP/MPLS IP Virtual Private Networks
        (VPNs)";

    }

    identity ospfv2-extended-prefix-flag {
      description
        "Base identity for the Extended Prefix TLV flag.";
    }

    identity a-flag {
      base ospfv2-extended-prefix-flag;
      description
        "Attach flag.  When set, it indicates that the prefix
corresponds to a route that is directly connected to
the advertising router.";
    }

    identity node-flag {
      base ospfv2-extended-prefix-flag;
      description
        "Node flag.  When set, it indicates that the prefix is
used to represent the advertising node, e.g., a loopback
address.";
    }

    typedef ospf-metric {
      type uint32 {
        range "0 .. 16777215";
      }
      description
        "OSPF metric.  24-bit unsigned integer.";
    }

    typedef ospf-link-metric {
      type uint16 {
        range "0 .. 65535";
      }
      description
        "OSPF link metric.  16-bit unsigned integer.";
    }

    typedef opaque-id {
      type uint32 {
        range "0 .. 16777215";
      }
      description
        "Opaque-LSA ID.  24-bit unsigned integer.";
    }

    typedef area-id-type {
      type yang:dotted-quad;
      description "Area ID type.";
    }

    typedef route-type {
      type enumeration {
        enum "intra-area" {
          value 0;
          description
            "OSPF intra-area route.";
        }
        enum "inter-area" {
          value 1;
          description
            "OSPF inter-area route.";
        }
        enum "external-1" {
          value 2;
          description
            "OSPF type 1 external route.";
        }
        enum "external-2" {
          value 3;
          description
            "OSPF type 2 external route.";
        }
        enum "nssa-1" {
          value 4;
          description
            "OSPF type 1 NSSA route.";
        }
        enum "nssa-2" {
          value 5;
          description
            "OSPF type 2 NSSA route.";
        }
      }
      description "OSPF route type.";
    }

    typedef if-state-type {
      type enumeration {
        enum "down" {
          value 1;
          description
            "Interface is in the 'Down' state.";
        }
        enum "loopback" {
          value 2;
          description
            "Interface is in the 'Loopback' state.";
        }
        enum "waiting" {
          value 3;
          description
            "Interface is in the 'Waiting' state.";
        }
        enum "point-to-point" {
          value 4;
          description
            "Interface is in the 'Point-to-point' state.";
        }
        enum "dr" {
          value 5;
          description
            "Interface is in the 'DR' (Designated Router) state.";
        }
        enum "bdr" {
          value 6;
          description
            "Interface is in the 'Backup' (Backup Designated Router
(BDR)) state.";
        }
        enum "dr-other" {
          value 7;
          description
            "Interface is in the 'DR Other' state.";
        }
      }
      description
        "OSPF interface state type.";
      reference
        "RFC 2328: OSPF Version 2";

    }

    typedef router-link-type {
      type enumeration {
        enum "point-to-point-link" {
          value 1;
          description
            "Point-to-point link to another router.";
        }
        enum "transit-network-link" {
          value 2;
          description
            "Link to a transit network, identified by the DR.";
        }
        enum "stub-network-link" {
          value 3;
          description
            "Link to a stub network, identified by the subnet.";
        }
        enum "virtual-link" {
          value 4;
          description
            "Virtual link across a transit area.";
        }
      }
      description "OSPF router link type.";
    }

    typedef nbr-state-type {
      type enumeration {
        enum "down" {
          value 1;
          description
            "Neighbor is in the 'Down' state.";
        }
        enum "attempt" {
          value 2;
          description
            "Neighbor is in the 'Attempt' state.";
        }
        enum "init" {
          value 3;
          description
            "Neighbor is in the 'Init' state.";
        }
        enum "2-way" {
          value 4;
          description
            "Neighbor is in the '2-Way' state.";
        }
        enum "exstart" {
          value 5;
          description
            "Neighbor is in the 'ExStart' (exchange start) state.";
        }
        enum "exchange" {
          value 6;
          description
            "Neighbor is in the 'Exchange' state.";
        }
        enum "loading" {
          value 7;
          description
            "Neighbor is in the 'Loading' state.";
        }
        enum "full" {
          value 8;
          description
            "Neighbor is in the 'Full' state.";
        }
      }
      description
        "OSPF neighbor state type.";
      reference
        "RFC 2328: OSPF Version 2";

    }

    typedef restart-helper-status-type {
      type enumeration {
        enum "not-helping" {
          value 1;
          description
            "Restart helper status of 'not-helping'.";
        }
        enum "helping" {
          value 2;
          description
            "Restart helper status of 'helping'.";
        }
      }
      description
        "Restart helper status type.";
    }

    typedef restart-exit-reason-type {
      type enumeration {
        enum "none" {
          value 1;
          description
            "Restart not attempted.";
        }
        enum "in-progress" {
          value 2;
          description "Restart in progress.";
        }
        enum "completed" {
          value 3;
          description
            "Restart successfully completed.";
        }
        enum "timed-out" {
          value 4;
          description "Restart timed out.";
        }
        enum "topology-changed" {
          value 5;
          description
            "Restart aborted due to a topology change.";
        }
      }
      description
        "Describes the outcome of the last graceful restart attempt.
The local router is being restarted or acting as a helper.";
    }

    typedef packet-type {
      type enumeration {
        enum "hello" {
          value 1;
          description "OSPF Hello packet.";
        }
        enum "database-description" {
          value 2;
          description
            "OSPF Database Description packet.";
        }
        enum "link-state-request" {
          value 3;
          description
            "OSPF Link State Request packet.";
        }
        enum "link-state-update" {
          value 4;
          description
            "OSPF Link State Update packet.";
        }
        enum "link-state-ack" {
          value 5;
          description
            "OSPF Link State Acknowledgment packet.";
        }
      }
      description "OSPF packet type.";
    }

    typedef nssa-translator-state-type {
      type enumeration {
        enum "enabled" {
          value 1;
          description
            "NSSATranslatorState is 'enabled'.";
        }
        enum "elected" {
          value 2;
          description
            "NSSATranslatorState is 'elected'.";
        }
        enum "disabled" {
          value 3;
          description
            "NSSATranslatorState is 'disabled'.";
        }
      }
      description
        "OSPF NSSA translator state type.";
      reference
        "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option";

    }

    typedef restart-status-type {
      type enumeration {
        enum "not-restarting" {
          value 1;
          description
            "The router is not restarting.";
        }
        enum "planned-restart" {
          value 2;
          description
            "The router is going through a planned restart.";
        }
        enum "unplanned-restart" {
          value 3;
          description
            "The router is going through an unplanned restart.";
        }
      }
      description
        "OSPF graceful restart status type.";
    }

    typedef fletcher-checksum16-type {
      type string {
        pattern '(0x)?[0-9a-fA-F]{4}';
      }
      description
        "Fletcher 16-bit checksum in hex-string format 0xXXXX.";
      reference
        "RFC 905: ISO Transport Protocol Specification ISO DP 8073";

    }

    typedef ospfv2-auth-trailer-rfc-version {
      type enumeration {
        enum "rfc5709" {
          value 0;
          description
            "Support for the OSPF authentication trailer as
described in RFC 5709.";
          reference
            "RFC 5709: OSPFv2 HMAC-SHA Cryptographic Authentication";

        }
        enum "rfc7474" {
          value 1;
          description
            "Support for the OSPF authentication trailer as
described in RFC 7474.";
          reference
            "RFC 7474: Security Extension for OSPFv2
            When Using Manual Key Management";

        }
      }
      description
        "OSPFv2 authentication trailer support.";
    }

    grouping tlv {
      description "Type-Length-Value (TLV).";
      leaf type {
        type uint16;
        description "TLV type.";
      }

      leaf length {
        type uint16;
        description "TLV length (octets).";
      }

      leaf value {
        type yang:hex-string;
        description "TLV value.";
      }
    }  // grouping tlv

    grouping unknown-tlvs {
      description
        "Grouping used for unknown TLVs or unknown sub-TLVs.";
      container unknown-tlvs {
        description "All unknown TLVs.";
        list unknown-tlv {
          description "Unknown TLV.";
          uses tlv;
        }  // list unknown-tlv
      }  // container unknown-tlvs
    }  // grouping unknown-tlvs

    grouping node-tag-tlv {
      description
        "OSPF Node Admin Tag TLV grouping.";
      list node-tag {
        description "List of tags.";
        leaf tag {
          type uint32;
          description
            "Value of the node administrative tag.";
        }
      }  // list node-tag
    }  // grouping node-tag-tlv

    grouping router-capabilities-tlv {
      description
        "Grouping for OSPF router capabilities TLV types.";
      reference
        "RFC 7770: Extensions to OSPF for Advertising Optional
        Router Capabilities";

      container router-informational-capabilities {
        description
          "OSPF Router Informational Flag definitions.";
        leaf-list informational-capabilities {
          type identityref {
            base informational-capability;
          }
          description
            "List of informational capabilities.  This list will
contain the identities for the informational
capabilities supported by the router.";
        }
      }  // container router-informational-capabilities

      list informational-capabilities-flags {
        description
          "List of informational capability flags.  This will
return all the 32-bit informational flags, irrespective
of whether or not they are known to the device.";
        leaf informational-flag {
          type uint32;
          description
            "Individual informational capability flag.";
        }
      }  // list informational-capabilities-flags

      list functional-capabilities {
        description
          "List of functional capability flags.  This will
return all the 32-bit functional flags, irrespective
of whether or not they are known to the device.";
        leaf functional-flag {
          type uint32;
          description
            "Individual functional capability flag.";
        }
      }  // list functional-capabilities
    }  // grouping router-capabilities-tlv

    grouping dynamic-hostname-tlv {
      description "Dynamic Hostname TLV.";
      reference
        "RFC 5642: Dynamic Hostname Exchange Mechanism for OSPF";

      leaf hostname {
        type string {
          length "1..255";
        }
        description "Dynamic hostname.";
      }
    }  // grouping dynamic-hostname-tlv

    grouping sbfd-discriminator-tlv {
      description "S-BFD Discriminator TLV.";
      reference
        "RFC 7884: OSPF Extensions to Advertise Seamless Bidirectional
        Forwarding Detection (S-BFD) Target Discriminators";

      list sbfd-discriminators {
        description
          "List of S-BFD Discriminators.";
        leaf sbfd-discriminator {
          type uint32;
          description
            "Individual S-BFD Discriminator.";
        }
      }  // list sbfd-discriminators
    }  // grouping sbfd-discriminator-tlv

    grouping maximum-sid-depth-tlv {
      description
        "Node MSD TLV (TLV for Maximum SID Depth).";
      reference
        "RFC 8476: Signaling Maximum SID Depth (MSD) Using OSPF";

      list msd-type {
        description "List of MSD tuples.";
        leaf msd-type {
          type uint8;
          description
            "Maximum SID Depth (MSD) type.";
        }

        leaf msd-value {
          type uint8;
          description
            "MSD value for the type.";
        }
      }  // list msd-type
    }  // grouping maximum-sid-depth-tlv

    grouping ospf-router-lsa-bits {
      description
        "Router-LSA bits.  Currently common to both OSPFv2 and
OSPFv3 but may diverge with future augmentations.";
      container router-bits {
        description "Router-LSA bits.";
        leaf-list rtr-lsa-bits {
          type identityref {
            base router-lsa-bit;
          }
          description
            "List of Router-LSA bits.  This list will contain
identities for the bits; these identities are set
in the Router-LSA bits.";
        }
      }  // container router-bits
    }  // grouping ospf-router-lsa-bits

    grouping ospfv2-router-link {
      description "OSPFv2 router link.";
      leaf link-id {
        type union {
          type inet:ipv4-address;
          type yang:dotted-quad;
        }
        description "Router-LSA Link ID.";
      }

      leaf link-data {
        type union {
          type inet:ipv4-address;
          type uint32;
        }
        description "Router-LSA link data.";
      }

      leaf type {
        type router-link-type;
        description "Router-LSA link type.";
      }
    }  // grouping ospfv2-router-link

    grouping ospfv2-lsa-body {
      description "OSPFv2 LSA body.";
      container router {
        when
          "derived-from-or-self(../../header/type, 'ospfv2-router-lsa')" {
          description
            "Only applies to Router-LSAs.";
        }
        description "Router-LSA.";
        uses ospf-router-lsa-bits;

        leaf num-of-links {
          type uint16;
          description
            "Number of links in the Router-LSA.";
        }

        container links {
          description "All router links.";
          list link {
            description "Router-LSA link.";
            uses ospfv2-router-link;

            container topologies {
              description
                "All topologies for the link.";
              list topology {
                description
                  "Topology-specific information.";
                leaf mt-id {
                  type uint8;
                  description
                    "The MT-ID for the topology enabled on the link.";
                }

                leaf metric {
                  type uint16;
                  description
                    "Metric for the topology.";
                }
              }  // list topology
            }  // container topologies
          }  // list link
        }  // container links
      }  // container router

      container network {
        when
          "derived-from-or-self(../../header/type, 'ospfv2-network-lsa')" {
          description
            "Only applies to Network-LSAs.";
        }
        description "Network-LSA.";
        leaf network-mask {
          type yang:dotted-quad;
          description
            "The IP address mask for the network.";
        }

        container attached-routers {
          description
            "All attached routers.";
          leaf-list attached-router {
            type inet:ipv4-address;
            description
              "List of the routers attached to the network.";
          }
        }  // container attached-routers
      }  // container network

      container summary {
        when
          "derived-from(../../header/type, 'ospfv2-summary-lsa-type')" {
          description
            "Only applies to summary LSAs.";
        }
        description "Summary LSA.";
        leaf network-mask {
          type inet:ipv4-address;
          description
            "The IP address mask for the network.";
        }

        container topologies {
          description
            "All topologies for the summary LSA.";
          list topology {
            description
              "Topology-specific information.";
            leaf mt-id {
              type uint8;
              description
                "The MT-ID for the topology enabled for the summary.";
            }

            leaf metric {
              type ospf-metric;
              description
                "Metric for the topology.";
            }
          }  // list topology
        }  // container topologies
      }  // container summary

      container external {
        when
          "derived-from(../../header/type, 'ospfv2-external-lsa-type')" {
          description
            "Only applies to AS-External-LSAs and NSSA-LSAs.";
        }
        description "External-LSA.";
        leaf network-mask {
          type inet:ipv4-address;
          description
            "The IP address mask for the network.";
        }

        container topologies {
          description
            "All topologies for the External-LSA.";
          list topology {
            description
              "Topology-specific information.";
            leaf mt-id {
              type uint8;
              description
                "The MT-ID for the topology enabled for the
external or NSSA prefix.";
            }

            leaf flags {
              type bits {
                bit E {
                  position 0;
                  description
                    "When set, the metric specified is a Type 2
external metric.";
                }
              }
              description "Topology flags.";
            }

            leaf metric {
              type ospf-metric;
              description
                "Metric for the topology.";
            }

            leaf forwarding-address {
              type inet:ipv4-address;
              description
                "IPv4 Forwarding address.";
            }

            leaf external-route-tag {
              type uint32;
              description
                "Route tag for the topology.";
            }
          }  // list topology
        }  // container topologies
      }  // container external

      container opaque {
        when
          "derived-from(../../header/type, 'ospfv2-opaque-lsa-type')" {
          description
            "Only applies to Opaque-LSAs.";
        }
        description "Opaque-LSA.";
        container ri-opaque {
          description
            "OSPF Router-Information-Opaque-LSA.";
          reference
            "RFC 7770: Extensions to OSPF for Advertising Optional
            Router Capabilities";

          container router-capabilities-tlv {
            description
              "Informational and functional router capabilities.";
            uses router-capabilities-tlv;
          }  // container router-capabilities-tlv

          container node-tag-tlvs {
            description
              "All Node Admin Tag TLVs.";
            list node-tag-tlv {
              description
                "Node Admin Tag TLV.";
              uses node-tag-tlv;
            }  // list node-tag-tlv
          }  // container node-tag-tlvs

          container dynamic-hostname-tlv {
            description
              "OSPF Dynamic Hostname TLV.";
            uses dynamic-hostname-tlv;
          }  // container dynamic-hostname-tlv

          container sbfd-discriminator-tlv {
            description
              "OSPF S-BFD Discriminator TLV.";
            uses sbfd-discriminator-tlv;
          }  // container sbfd-discriminator-tlv

          container maximum-sid-depth-tlv {
            description "OSPF Node MSD TLV.";
            uses maximum-sid-depth-tlv;
          }  // container maximum-sid-depth-tlv

          uses unknown-tlvs;
        }  // container ri-opaque

        container te-opaque {
          description
            "OSPFv2 TE Opaque-LSA.";
          reference
            "RFC 3630: Traffic Engineering (TE) Extensions to
            OSPF Version 2";

          container router-address-tlv {
            description
              "Router address TLV.";
            leaf router-address {
              type inet:ipv4-address;
              description "Router address.";
            }
          }  // container router-address-tlv

          container link-tlv {
            description
              "Describes a single link.  It is constructed
from a set of sub-TLVs.";
            leaf link-type {
              type router-link-type;
              mandatory true;
              description "Link type.";
            }

            leaf link-id {
              type union {
                type inet:ipv4-address;
                type yang:dotted-quad;
              }
              mandatory true;
              description "Link ID.";
            }

            container local-if-ipv4-addrs {
              description
                "All local interface IPv4 addresses.";
              leaf-list local-if-ipv4-addr {
                type inet:ipv4-address;
                description
                  "List of local interface IPv4 addresses.";
              }
            }  // container local-if-ipv4-addrs

            container remote-if-ipv4-addrs {
              description
                "All remote interface IPv4 addresses.";
              leaf-list remote-if-ipv4-addr {
                type inet:ipv4-address;
                description
                  "List of remote interface IPv4 addresses.";
              }
            }  // container remote-if-ipv4-addrs

            leaf te-metric {
              type uint32;
              description "TE metric.";
            }

            leaf max-bandwidth {
              type rt-types:bandwidth-ieee-float32;
              description
                "Maximum bandwidth.";
            }

            leaf max-reservable-bandwidth {
              type rt-types:bandwidth-ieee-float32;
              description
                "Maximum reservable bandwidth.";
            }

            container unreserved-bandwidths {
              description
                "All unreserved bandwidths.";
              list unreserved-bandwidth {
                description
                  "List of unreserved bandwidths for different
priorities.";
                leaf priority {
                  type uint8 {
                    range "0 .. 7";
                  }
                  description
                    "Priority from 0 to 7.";
                }

                leaf unreserved-bandwidth {
                  type rt-types:bandwidth-ieee-float32;
                  description
                    "Unreserved bandwidth.";
                }
              }  // list unreserved-bandwidth
            }  // container unreserved-bandwidths

            leaf admin-group {
              type uint32;
              description
                "Administrative Group / Resource Class/Color.";
            }

            uses unknown-tlvs;
          }  // container link-tlv
        }  // container te-opaque

        container extended-prefix-opaque {
          description
            "All Extended Prefix TLVs in the LSA.";
          list extended-prefix-tlv {
            description
              "Extended Prefix TLV.";
            leaf route-type {
              type enumeration {
                enum "unspecified" {
                  value 0;
                  description "Unspecified.";
                }
                enum "intra-area" {
                  value 1;
                  description
                    "OSPF intra-area route.";
                }
                enum "inter-area" {
                  value 3;
                  description
                    "OSPF inter-area route.";
                }
                enum "external" {
                  value 5;
                  description
                    "OSPF external route.";
                }
                enum "nssa" {
                  value 7;
                  description
                    "OSPF NSSA external route.";
                }
              }
              description "Route type.";
            }

            container flags {
              description "Prefix flags.";
              leaf-list extended-prefix-flags {
                type identityref {
                  base ospfv2-extended-prefix-flag;
                }
                description
                  "List of Extended Prefix TLV flags.  This list will
contain identities for the prefix flags; these
identities are set in the extended prefix flags.";
              }
            }  // container flags

            leaf prefix {
              type inet:ip-prefix;
              description "Address prefix.";
            }

            uses unknown-tlvs;
          }  // list extended-prefix-tlv
        }  // container extended-prefix-opaque

        container extended-link-opaque {
          description
            "All Extended Link TLVs in the LSA.";
          reference
            "RFC 7684: OSPFv2 Prefix/Link Attribute Advertisement";

          container extended-link-tlv {
            description "Extended Link TLV.";
            uses ospfv2-router-link;

            container maximum-sid-depth-tlv {
              description
                "OSPF Node MSD TLV.";
              uses maximum-sid-depth-tlv;
            }  // container maximum-sid-depth-tlv

            uses unknown-tlvs;
          }  // container extended-link-tlv
        }  // container extended-link-opaque
      }  // container opaque
    }  // grouping ospfv2-lsa-body

    grouping ospfv3-lsa-options {
      description "OSPFv3 LSA Options.";
      container lsa-options {
        description "OSPFv3 LSA Options.";
        leaf-list lsa-options {
          type identityref {
            base ospfv3-lsa-option;
          }
          description
            "List of OSPFv3 LSA Options.  This list will contain
the identities for the OSPFv3 LSA Options that are
set for the LSA.";
        }
      }  // container lsa-options
    }  // grouping ospfv3-lsa-options

    grouping ospfv3-lsa-prefix {
      description "OSPFv3 LSA prefix.";
      leaf prefix {
        type inet:ip-prefix;
        description "LSA prefix.";
      }

      container prefix-options {
        description "Prefix options.";
        leaf-list prefix-options {
          type identityref {
            base ospfv3-prefix-option;
          }
          description
            "List of OSPFv3 prefix Options.  This list will
contain the identities for the OSPFv3 options
that are set for the OSPFv3 prefix.";
        }
      }  // container prefix-options
    }  // grouping ospfv3-lsa-prefix

    grouping ospfv3-lsa-external {
      description
        "AS-External-LSA or NSSA-LSA.";
      leaf metric {
        type ospf-metric;
        description
          "AS-External-LSA or NSSA-LSA Metric.";
      }

      leaf flags {
        type bits {
          bit E {
            position 0;
            description
              "When set, the metric specified is a Type 2
external metric.";
          }
          bit F {
            position 1;
            description
              "When set, a forwarding address is included
in the LSA.";
          }
          bit T {
            position 2;
            description
              "When set, an external route tag is included
in the LSA.";
          }
        }
        description
          "AS-External-LSA or NSSA-LSA flags.";
      }

      leaf referenced-ls-type {
        type identityref {
          base ospfv3-lsa-type;
        }
        description
          "Referenced Link State (LS) Type.";
        reference
          "RFC 5340: OSPF for IPv6";

      }

      leaf unknown-referenced-ls-type {
        type uint16;
        description
          "Value for an unknown Referenced LS Type.";
      }

      uses ospfv3-lsa-prefix;

      leaf forwarding-address {
        type inet:ipv6-address;
        description
          "IPv6 Forwarding address.";
      }

      leaf external-route-tag {
        type uint32;
        description "Route tag.";
      }

      leaf referenced-link-state-id {
        type uint32;
        description
          "Referenced Link State ID.";
        reference
          "RFC 5340: OSPF for IPv6";

      }
    }  // grouping ospfv3-lsa-external

    grouping ospfv3-lsa-body {
      description "OSPFv3 LSA body.";
      container router {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-router-lsa')" {
          description
            "Only applies to Router-LSAs.";
        }
        description "Router-LSA.";
        uses ospf-router-lsa-bits;

        uses ospfv3-lsa-options;

        container links {
          description "All router links.";
          list link {
            description "Router-LSA link.";
            leaf interface-id {
              type uint32;
              description
                "Interface ID for the link.";
            }

            leaf neighbor-interface-id {
              type uint32;
              description
                "Neighbor's Interface ID for the link.";
            }

            leaf neighbor-router-id {
              type rt-types:router-id;
              description
                "Neighbor's Router ID for the link.";
            }

            leaf type {
              type router-link-type;
              description
                "Link type: 1 - Point-to-Point Link
	   2 - Transit Network Link
	   3 - Reserved for OSPFv3 Links
	   4 - Virtual Link.";
            }

            leaf metric {
              type uint16;
              description "Link metric.";
            }
          }  // list link
        }  // container links
      }  // container router

      container network {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-network-lsa')" {
          description
            "Only applies to Network-LSAs.";
        }
        description "Network-LSA.";
        uses ospfv3-lsa-options;

        container attached-routers {
          description
            "All attached routers.";
          leaf-list attached-router {
            type rt-types:router-id;
            description
              "List of the routers attached to the network.";
          }
        }  // container attached-routers
      }  // container network

      container inter-area-prefix {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-inter-area-prefix-lsa')" {
          description
            "Only applies to Inter-Area-Prefix-LSAs.";
        }
        description "Prefix-LSA.";
        leaf metric {
          type ospf-metric;
          description
            "Inter-Area Prefix metric.";
        }

        uses ospfv3-lsa-prefix;
      }  // container inter-area-prefix

      container inter-area-router {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-inter-area-router-lsa')" {
          description
            "Only applies to Inter-Area-Router-LSAs.";
        }
        description "Inter-Area-Router-LSA.";
        uses ospfv3-lsa-options;

        leaf metric {
          type ospf-metric;
          description
            "Autonomous System Boundary Router (ASBR) metric.";
        }

        leaf destination-router-id {
          type rt-types:router-id;
          description
            "The Router ID of the ASBR described by the LSA.";
        }
      }  // container inter-area-router

      container as-external {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-as-external-lsa')" {
          description
            "Only applies to AS-External-LSAs.";
        }
        description "AS-External-LSA.";
        uses ospfv3-lsa-external;
      }  // container as-external

      container nssa {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-nssa-lsa')" {
          description
            "Only applies to NSSA-LSAs.";
        }
        description "NSSA-LSA.";
        uses ospfv3-lsa-external;
      }  // container nssa

      container link {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-link-lsa')" {
          description
            "Only applies to Link-LSAs.";
        }
        description "Link-LSA.";
        leaf rtr-priority {
          type uint8;
          description
            "Router priority for DR election.  A router with a
higher priority will be preferred in the election.
A value of 0 indicates that the router is not eligible
to become the DR or BDR.";
        }

        uses ospfv3-lsa-options;

        leaf link-local-interface-address {
          type inet:ipv6-address;
          description
            "The originating router's link-local
interface address for the link.";
        }

        leaf num-of-prefixes {
          type uint32;
          description "Number of prefixes.";
        }

        container prefixes {
          description
            "All prefixes for the link.";
          list prefix {
            description
              "List of prefixes associated with the link.";
            uses ospfv3-lsa-prefix;
          }  // list prefix
        }  // container prefixes
      }  // container link

      container intra-area-prefix {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-intra-area-prefix-lsa')" {
          description
            "Only applies to Intra-Area-Prefix-LSAs.";
        }
        description "Intra-Area-Prefix-LSA.";
        leaf referenced-ls-type {
          type identityref {
            base ospfv3-lsa-type;
          }
          description "Referenced LS Type.";
        }

        leaf unknown-referenced-ls-type {
          type uint16;
          description
            "Value for an unknown Referenced LS Type.";
        }

        leaf referenced-link-state-id {
          type uint32;
          description
            "Referenced Link State ID.";
        }

        leaf referenced-adv-router {
          type rt-types:router-id;
          description
            "Referenced Advertising Router.";
          reference
            "RFC 5340: OSPF for IPv6";

        }

        leaf num-of-prefixes {
          type uint16;
          description "Number of prefixes.";
        }

        container prefixes {
          description
            "All prefixes in this LSA.";
          list prefix {
            description
              "List of prefixes in this LSA.";
            uses ospfv3-lsa-prefix;

            leaf metric {
              type uint16;
              description "Prefix metric.";
            }
          }  // list prefix
        }  // container prefixes
      }  // container intra-area-prefix

      container router-information {
        when
          "derived-from-or-self(../../header/type, 'ospfv3-router-information-lsa')" {
          description
            "Only applies to Router-Information-LSAs (RFC 7770).";
          reference
            "RFC 7770: Extensions to OSPF for Advertising Optional
            Router Capabilities";

        }
        description
          "Router-Information-LSA.";
        reference
          "RFC 7770: Extensions to OSPF for Advertising Optional
          Router Capabilities";

        container router-capabilities-tlv {
          description
            "Informational and functional router capabilities.";
          uses router-capabilities-tlv;
        }  // container router-capabilities-tlv

        container node-tag-tlvs {
          description
            "All Node Admin Tag TLVs.";
          list node-tag-tlv {
            description
              "Node Admin Tag TLV.";
            uses node-tag-tlv;
          }  // list node-tag-tlv
        }  // container node-tag-tlvs

        container dynamic-hostname-tlv {
          description
            "OSPF Dynamic Hostname TLV.";
          uses dynamic-hostname-tlv;
        }  // container dynamic-hostname-tlv

        container sbfd-discriminator-tlv {
          description
            "OSPF S-BFD Discriminator TLV.";
          uses sbfd-discriminator-tlv;
        }  // container sbfd-discriminator-tlv
      }  // container router-information
    }  // grouping ospfv3-lsa-body

    grouping lsa-header {
      description
        "Common LSA for OSPFv2 and OSPFv3.";
      leaf age {
        type uint16;
        mandatory true;
        description "LSA age.";
      }

      leaf type {
        type identityref {
          base ospf-lsa-type;
        }
        mandatory true;
        description "LSA type.";
      }

      leaf adv-router {
        type rt-types:router-id;
        mandatory true;
        description
          "LSA advertising router.";
      }

      leaf seq-num {
        type uint32;
        mandatory true;
        description "LSA sequence number.";
      }

      leaf checksum {
        type fletcher-checksum16-type;
        mandatory true;
        description "LSA checksum.";
      }

      leaf length {
        type uint16;
        mandatory true;
        description
          "LSA length, including the header.";
      }
    }  // grouping lsa-header

    grouping ospfv2-lsa {
      description
        "OSPFv2 LSA.  LSAs are uniquely identified by
the <LSA Type, Link State ID, Advertising Router>
tuple, with the sequence number differentiating the
LSA instances.";
      container header {
        must
          "(derived-from(type, 'ospfv2-opaque-lsa-type') and opaque-id and opaque-type) or (not(derived-from(type, 'ospfv2-opaque-lsa-type')) and not(opaque-id) and not(opaque-type))" {
          description
            "The opaque-type and the opaque-id only apply to
Opaque-LSAs.";
        }
        description
          "Decoded OSPFv2 LSA header data.";
        container lsa-options {
          description "LSA Options.";
          leaf-list lsa-options {
            type identityref {
              base ospfv2-lsa-option;
            }
            description
              "List of LSA Options.  This list will contain the
identities for the OSPFv2 LSA Options that are set.";
          }
        }  // container lsa-options

        leaf lsa-id {
          type yang:dotted-quad;
          mandatory true;
          description "Link State ID.";
        }

        leaf opaque-type {
          type uint8;
          description "Opaque-LSA type.";
        }

        leaf opaque-id {
          type opaque-id;
          description "Opaque-LSA ID.";
        }

        uses lsa-header;
      }  // container header

      container body {
        description
          "Decoded OSPFv2 LSA body data.";
        uses ospfv2-lsa-body;
      }  // container body
    }  // grouping ospfv2-lsa

    grouping ospfv3-lsa {
      description "Decoded OSPFv3 LSA.";
      container header {
        description
          "Decoded OSPFv3 LSA header data.";
        leaf lsa-id {
          type uint32;
          mandatory true;
          description "OSPFv3 LSA ID.";
        }

        uses lsa-header;
      }  // container header

      container body {
        description
          "Decoded OSPF LSA body data.";
        uses ospfv3-lsa-body;
      }  // container body
    }  // grouping ospfv3-lsa

    grouping lsa-common {
      description
        "Common fields for OSPF LSA representation.";
      leaf decode-completed {
        type boolean;
        description
          "The OSPF LSA body was successfully decoded, except for
unknown TLVs.  Unknown LSA types and OSPFv2 unknown
Opaque-LSA types are not decoded.  Additionally,
malformed LSAs are generally not accepted and will
not be in the Link State Database (LSDB).";
      }

      leaf raw-data {
        type yang:hex-string;
        description
          "The hexadecimal representation of the complete LSA as
received or originated, in network byte order.";
      }
    }  // grouping lsa-common

    grouping lsa {
      description "OSPF LSA.";
      uses lsa-common;

      choice version {
        description
          "OSPFv2 or OSPFv3 LSA body.";
        container ospfv2 {
          description "OSPFv2 LSA.";
          uses ospfv2-lsa;
        }  // container ospfv2
        container ospfv3 {
          description "OSPFv3 LSA.";
          uses ospfv3-lsa;
        }  // container ospfv3
      }  // choice version
    }  // grouping lsa

    grouping lsa-key {
      description
        "OSPF LSA key.  The database key for each LSA of a given
type in the LSDB.";
      leaf lsa-id {
        type union {
          type yang:dotted-quad;
          type uint32;
        }
        description "Link State ID.";
      }

      leaf adv-router {
        type rt-types:router-id;
        description "Advertising router.";
      }
    }  // grouping lsa-key

    grouping instance-stat {
      description "Per-instance statistics.";
      leaf discontinuity-time {
        type yang:date-and-time;
        description
          "The time of the most recent occasion at which any one or
more of this OSPF instance's counters suffered a
discontinuity.  If no such discontinuities have occurred
since the OSPF instance was last reinitialized, then
this node contains the time the OSPF instance was
reinitialized, which normally occurs when it was
created.";
      }

      leaf originate-new-lsa-count {
        type yang:counter32;
        description
          "The number of new LSAs originated.  Discontinuities in the
value of this counter can occur when the OSPF instance is
reinitialized.";
      }

      leaf rx-new-lsas-count {
        type yang:counter32;
        description
          "The number of new LSAs received.  Discontinuities in the
value of this counter can occur when the OSPF instance is
reinitialized.";
      }

      leaf as-scope-lsa-count {
        type yang:gauge32;
        description
          "The number of AS-Scope LSAs.";
      }

      leaf as-scope-lsa-chksum-sum {
        type uint32;
        description
          "The modulo 2^32 sum of the LSA checksums
for AS-Scope LSAs.  The value should be treated as
unsigned when comparing two sums of checksums.  While
differing checksums indicate a different combination
of LSAs, equivalent checksums don't guarantee that the
LSAs are the same, given that multiple combinations of
LSAs can result in the same checksum.";
      }

      container database {
        description
          "Container for per-AS-Scope LSA statistics.";
        list as-scope-lsa-type {
          description
            "List of AS-Scope LSA statistics.";
          leaf lsa-type {
            type uint16;
            description "AS-Scope LSA type.";
          }

          leaf lsa-count {
            type yang:gauge32;
            description
              "The number of LSAs of this LSA type.";
          }

          leaf lsa-cksum-sum {
            type uint32;
            description
              "The modulo 2^32 sum of the LSA checksums
for LSAs of this type.  The value should be
treated as unsigned when comparing two sums of
checksums.  While differing checksums indicate a
different combination of LSAs, equivalent checksums
don't guarantee that the LSAs are the same, given that
multiple combinations of LSAs can result in the same
checksum.";
          }
        }  // list as-scope-lsa-type
      }  // container database

      uses instance-fast-reroute-state;
    }  // grouping instance-stat

    grouping area-stat {
      description "Per-area statistics.";
      leaf discontinuity-time {
        type yang:date-and-time;
        description
          "The time of the most recent occasion at which any one or
more of this OSPF area's counters suffered a
discontinuity.  If no such discontinuities have occurred
since the OSPF area was last reinitialized, then
this node contains the time the OSPF area was
reinitialized, which normally occurs when it was
created.";
      }

      leaf spf-runs-count {
        type yang:counter32;
        description
          "The number of times the intra-area SPF has run.
Discontinuities in the value of this counter can occur
when the OSPF area is reinitialized.";
      }

      leaf abr-count {
        type yang:gauge32;
        description
          "The total number of Area Border Routers (ABRs)
reachable within this area.";
      }

      leaf asbr-count {
        type yang:gauge32;
        description
          "The total number of AS Boundary Routers (ASBRs)
reachable within this area.";
      }

      leaf ar-nssa-translator-event-count {
        type yang:counter32;
        description
          "The number of NSSA translator-state changes.
Discontinuities in the value of this counter can occur
when the OSPF area is reinitialized.";
      }

      leaf area-scope-lsa-count {
        type yang:gauge32;
        description
          "The number of area-scope LSAs in the area.";
      }

      leaf area-scope-lsa-cksum-sum {
        type uint32;
        description
          "The modulo 2^32 sum of the LSA checksums
for area-scope LSAs.  The value should be treated as
unsigned when comparing two sums of checksums.  While
differing checksums indicate a different combination
of LSAs, equivalent checksums don't guarantee that the
LSAs are the same, given that multiple combinations of
LSAs can result in the same checksum.";
      }

      container database {
        description
          "Container for area-scope LSA type statistics.";
        list area-scope-lsa-type {
          description
            "List of area-scope LSA statistics.";
          leaf lsa-type {
            type uint16;
            description
              "Area-scope LSA type.";
          }

          leaf lsa-count {
            type yang:gauge32;
            description
              "The number of LSAs of this LSA type.";
          }

          leaf lsa-cksum-sum {
            type uint32;
            description
              "The modulo 2^32 sum of the LSA checksums
for LSAs of this type.  The value should be
treated as unsigned when comparing two sums of
checksums.  While differing checksums indicate a
different combination of LSAs, equivalent checksums
don't guarantee that the LSAs are the same, given that
multiple combinations of LSAs can result in the same
checksum.";
          }
        }  // list area-scope-lsa-type
      }  // container database
    }  // grouping area-stat

    grouping interface-stat {
      description
        "Per-interface statistics.";
      leaf discontinuity-time {
        type yang:date-and-time;
        description
          "The time of the most recent occasion at which any one or
more of this OSPF interface's counters suffered a
discontinuity.  If no such discontinuities have occurred
since the OSPF interface was last reinitialized, then
this node contains the time the OSPF interface was
reinitialized, which normally occurs when it was
created.";
      }

      leaf if-event-count {
        type yang:counter32;
        description
          "The number of times this interface has changed its
state or an error has occurred.  Discontinuities in the
value of this counter can occur when the OSPF interface
is reinitialized.";
      }

      leaf link-scope-lsa-count {
        type yang:gauge32;
        description
          "The number of link-scope LSAs.";
      }

      leaf link-scope-lsa-cksum-sum {
        type uint32;
        description
          "The modulo 2^32 sum of the LSA checksums
for link-scope LSAs.  The value should be treated as
unsigned when comparing two sums of checksums.  While
differing checksums indicate a different combination
of LSAs, equivalent checksums don't guarantee that the
LSAs are the same, given that multiple combinations of
LSAs can result in the same checksum.";
      }

      container database {
        description
          "Container for link-scope LSA type statistics.";
        list link-scope-lsa-type {
          description
            "List of link-scope LSA statistics.";
          leaf lsa-type {
            type uint16;
            description
              "Link-scope LSA type.";
          }

          leaf lsa-count {
            type yang:gauge32;
            description
              "The number of LSAs of this LSA type.";
          }

          leaf lsa-cksum-sum {
            type uint32;
            description
              "The modulo 2^32 sum of the LSA checksums
for LSAs of this type.  The value should be
treated as unsigned when comparing two sums of
checksums.  While differing checksums indicate a
different combination of LSAs, equivalent checksums
don't guarantee that the LSAs are the same, given that
multiple combinations of LSAs can result in the same
checksum.";
          }
        }  // list link-scope-lsa-type
      }  // container database
    }  // grouping interface-stat

    grouping neighbor-stat {
      description "Per-neighbor statistics.";
      leaf discontinuity-time {
        type yang:date-and-time;
        description
          "The time of the most recent occasion at which any one or
more of this OSPF neighbor's counters suffered a
discontinuity.  If no such discontinuities have occurred
since the OSPF neighbor was last reinitialized, then
this node contains the time the OSPF neighbor was
reinitialized, which normally occurs when the neighbor
is dynamically discovered and created.";
      }

      leaf nbr-event-count {
        type yang:counter32;
        description
          "The number of times this neighbor has changed
state or an error has occurred.  Discontinuities in the
value of this counter can occur when the OSPF neighbor
is reinitialized.";
      }

      leaf nbr-retrans-qlen {
        type yang:gauge32;
        description
          "The current length of the retransmission queue.";
      }
    }  // grouping neighbor-stat

    grouping instance-fast-reroute-config {
      description
        "This group defines the global configuration of
IP Fast Reroute (IP-FRR).";
      container fast-reroute {
        if-feature fast-reroute;
        description
          "This container may be augmented with global
parameters for IP-FRR.";
        container lfa {
          if-feature lfa;
          description
            "This container may be augmented with
global parameters for Loop-Free Alternates (LFAs).
Container creation has no effect on LFA activation.";
        }  // container lfa
      }  // container fast-reroute
    }  // grouping instance-fast-reroute-config

    grouping instance-fast-reroute-state {
      description
        "IP-FRR state data grouping.";
      container protected-routes {
        if-feature fast-reroute;
        config false;
        description
          "Instance protection statistics.";
        list address-family-stats {
          key "address-family prefix alternate";
          description
            "Per-Address-Family (AF) protected prefix information.";
          leaf address-family {
            type iana-rt-types:address-family;
            description "Address family.";
          }

          leaf prefix {
            type inet:ip-prefix;
            description "Protected prefix.";
          }

          leaf alternate {
            type inet:ip-address;
            description
              "Alternate next hop for the prefix.";
          }

          leaf alternate-type {
            type enumeration {
              enum "equal-cost" {
                value 0;
                description
                  "ECMP-based alternate.";
              }
              enum "lfa" {
                value 1;
                description
                  "LFA-based alternate.";
              }
              enum "remote-lfa" {
                value 2;
                description
                  "Remote-LFA-based alternate.";
              }
              enum "tunnel" {
                value 3;
                description
                  "Tunnel-based alternate (like RSVP-TE or GRE).";
              }
              enum "ti-lfa" {
                value 4;
                description
                  "An alternate based on Topology-Independent
Loop-Free Alternate (TI-LFA).";
              }
              enum "mrt" {
                value 5;
                description
                  "An alternate based on Maximally Redundant Trees
(MRTs).";
              }
              enum "other" {
                value 6;
                description
                  "Unknown alternate type.";
              }
            }
            description "Type of alternate.";
          }

          leaf best {
            type boolean;
            description
              "Indicates that this alternate is preferred.";
          }

          leaf non-best-reason {
            type string {
              length "1..255";
            }
            description
              "Information field used to describe why the alternate
is not the best choice.";
          }

          leaf protection-available {
            type bits {
              bit node-protect {
                position 0;
                description
                  "Node protection available.";
              }
              bit link-protect {
                position 1;
                description
                  "Link protection available.";
              }
              bit srlg-protect {
                position 2;
                description
                  "Shared Risk Link Group (SRLG) protection
available.";
              }
              bit downstream-protect {
                position 3;
                description
                  "Downstream protection available.";
              }
              bit other {
                position 4;
                description
                  "Other protection available.";
              }
            }
            description
              "Protection provided by the alternate.";
          }

          leaf alternate-metric-1 {
            type uint32;
            description
              "Metric from the Point of Local Repair (PLR) to
the destination through the alternate path.";
          }

          leaf alternate-metric-2 {
            type uint32;
            description
              "Metric from the PLR to the alternate node.";
          }

          leaf alternate-metric-3 {
            type uint32;
            description
              "Metric from the alternate node to the destination.";
          }
        }  // list address-family-stats
      }  // container protected-routes

      container unprotected-routes {
        if-feature fast-reroute;
        config false;
        description
          "List of prefixes that are not protected.";
        list address-family-stats {
          key "address-family prefix";
          description
            "Per-AF unprotected prefix statistics.";
          leaf address-family {
            type iana-rt-types:address-family;
            description "Address family.";
          }

          leaf prefix {
            type inet:ip-prefix;
            description
              "Unprotected prefix.";
          }
        }  // list address-family-stats
      }  // container unprotected-routes

      list protection-statistics {
        key "frr-protection-method";
        config false;
        description
          "List of protection method statistics.";
        leaf frr-protection-method {
          type string;
          description
            "Protection method used.";
        }

        list address-family-stats {
          key "address-family";
          description
            "Per-AF protection statistics.";
          leaf address-family {
            type iana-rt-types:address-family;
            description "Address family.";
          }

          leaf total-routes {
            type uint32;
            description "Total prefixes.";
          }

          leaf unprotected-routes {
            type uint32;
            description
              "Total prefixes that are not protected.";
          }

          leaf protected-routes {
            type uint32;
            description
              "Total prefixes that are protected.";
          }

          leaf linkprotected-routes {
            type uint32;
            description
              "Total prefixes that are link protected.";
          }

          leaf nodeprotected-routes {
            type uint32;
            description
              "Total prefixes that are node protected.";
          }
        }  // list address-family-stats
      }  // list protection-statistics
    }  // grouping instance-fast-reroute-state

    grouping interface-fast-reroute-config {
      description
        "This group defines interface configuration of IP-FRR.";
      container fast-reroute {
        if-feature fast-reroute;
        description
          "Interface IP-FRR configuration.";
        container lfa {
          if-feature lfa;
          description "LFA configuration.";
          leaf candidate-enabled {
            type boolean;
            default "true";
            description
              "Enables the interface to be used as a backup.";
          }

          leaf enabled {
            type boolean;
            default "false";
            description
              "Activates an LFA.  Per-prefix LFA computation
is assumed.";
          }

          container remote-lfa {
            if-feature remote-lfa;
            description
              "R-LFA configuration.";
            leaf enabled {
              type boolean;
              default "false";
              description
                "Activates a Remote LFA (R-LFA).";
            }
          }  // container remote-lfa
        }  // container lfa
      }  // container fast-reroute
    }  // grouping interface-fast-reroute-config

    grouping interface-physical-link-config {
      description
        "Interface cost configuration that only applies to
physical interfaces (non-virtual) and sham links.";
      leaf cost {
        type ospf-link-metric;
        description "Interface's cost.";
      }

      leaf mtu-ignore {
        if-feature mtu-ignore;
        type boolean;
        description
          "Enables/disables bypassing the MTU mismatch check in
Database Description packets as specified in Section 10.6
of RFC 2328.";
        reference
          "RFC 2328: OSPF Version 2, Section 10.6";

      }

      leaf prefix-suppression {
        if-feature prefix-suppression;
        type boolean;
        description
          "Suppresses advertisement of the prefixes associated
with the interface.";
      }
    }  // grouping interface-physical-link-config

    grouping interface-common-config {
      description
        "Common configuration for all types of interfaces,
including virtual links and sham links.";
      leaf hello-interval {
        type uint16;
        units "seconds";
        description
          "Interval between Hello packets (seconds).  It must
be the same for all routers on the same network.
Different networks, implementations, and deployments
will use different Hello intervals.  A sample value
for a LAN network would be 10 seconds.";
        reference
          "RFC 2328: OSPF Version 2, Appendix C.3";

      }

      leaf dead-interval {
        type uint16;
        units "seconds";
        must
          "../dead-interval > ../hello-interval" {
          error-message
            "The dead interval must be larger than the Hello interval";
          description
            "The value must be greater than 'hello-interval'.";
        }
        description
          "Interval after which a neighbor is declared down
(seconds) if Hello packets are not received.  It is
typically 3 or 4 times the 'hello-interval' period.
A typical value for LAN networks is 40 seconds.";
        reference
          "RFC 2328: OSPF Version 2, Appendix C.3";

      }

      leaf retransmit-interval {
        type uint16 {
          range "1..3600";
        }
        units "seconds";
        description
          "Interval between retransmitting unacknowledged Link
State Advertisements (LSAs) (seconds).  This should
be well over the round-trip transmit delay for
any two routers on the network.  A sample value
would be 5 seconds.";
        reference
          "RFC 2328: OSPF Version 2, Appendix C.3";

      }

      leaf transmit-delay {
        type uint16;
        units "seconds";
        description
          "Estimated time needed to transmit Link State Update
(LSU) packets on the interface (seconds).  LSAs have
their age incremented by this amount when advertised
on the interface.  A sample value would be 1 second.";
        reference
          "RFC 2328: OSPF Version 2, Appendix C.3";

      }

      leaf lls {
        if-feature lls;
        type boolean;
        description
          "Enables/disables link-local signaling (LLS) support.";
      }

      container ttl-security {
        if-feature ttl-security;
        description
          "Time to Live (TTL) security checking.";
        leaf enabled {
          type boolean;
          description
            "Enables/disables TTL security checking.";
        }

        leaf hops {
          type uint8 {
            range "1..254";
          }
          default "1";
          description
            "Maximum number of hops that an OSPF packet may
have traversed before reception.";
        }
      }  // container ttl-security

      leaf enabled {
        type boolean;
        default "true";
        description
          "Enables/disables the OSPF protocol on the interface.";
      }

      container authentication {
        description
          "Authentication configuration.";
        choice auth-type-selection {
          description
            "Options for OSPFv2/OSPFv3 authentication
configuration.";
          case ospfv2-auth {
            when
              "derived-from-or-self(../../../../../../rt:type, 'ospfv2')" {
              description
                "Applied to OSPFv2 only.";
            }
            leaf ospfv2-auth-trailer-rfc {
              if-feature ospfv2-authentication-trailer;
              type ospfv2-auth-trailer-rfc-version;
              description
                "Version of OSPFv2 authentication trailer support.
See RFCs 5709 and 7474.";
              reference
                "RFC 5709: OSPFv2 HMAC-SHA Cryptographic Authentication
                 RFC 7474: Security Extension for OSPFv2 When Using
                Manual Key Management";

            }

            choice ospfv2-auth-specification {
              description
                "Key chain or explicit key parameter specification.";
              case auth-key-chain {
                if-feature key-chain;
                leaf ospfv2-key-chain {
                  type key-chain:key-chain-ref;
                  description
                    "Name of the key chain.";
                }
              }  // case auth-key-chain

              case auth-key-explicit {
                leaf ospfv2-key-id {
                  type uint32;
                  description
                    "Key identifier.";
                }

                leaf ospfv2-key {
                  type string;
                  description
                    "OSPFv2 authentication key.  The
length of the key may be dependent on the
cryptographic algorithm.";
                }

                leaf ospfv2-crypto-algorithm {
                  type identityref {
                    base key-chain:crypto-algorithm;
                  }
                  description
                    "Cryptographic algorithm associated with the key.";
                }
              }  // case auth-key-explicit
            }  // choice ospfv2-auth-specification
          }  // case ospfv2-auth

          case ospfv3-auth-ipsec {
            when
              "derived-from-or-self(../../../../../../rt:type, 'ospfv3')" {
              description
                "Applied to OSPFv3 only.";
            }
            if-feature ospfv3-authentication-ipsec;
            leaf sa {
              type string;
              description
                "Name of the Security Association (SA).";
            }
          }  // case ospfv3-auth-ipsec

          case ospfv3-auth-trailer {
            when
              "derived-from-or-self(../../../../../../rt:type, 'ospfv3')" {
              description
                "Applied to OSPFv3 only.";
            }
            if-feature ospfv3-authentication-trailer;
            choice ospfv3-auth-specification {
              description
                "Key chain or explicit key parameter specification.";
              case auth-key-chain {
                if-feature key-chain;
                leaf ospfv3-key-chain {
                  type key-chain:key-chain-ref;
                  description
                    "Name of the key chain.";
                }
              }  // case auth-key-chain

              case auth-key-explicit {
                leaf ospfv3-sa-id {
                  type uint16;
                  description
                    "Security Association (SA) Identifier.";
                }

                leaf ospfv3-key {
                  type string;
                  description
                    "OSPFv3 authentication key.  The
length of the key may be dependent on the
cryptographic algorithm.";
                }

                leaf ospfv3-crypto-algorithm {
                  type identityref {
                    base key-chain:crypto-algorithm;
                  }
                  description
                    "Cryptographic algorithm associated with the key.";
                }
              }  // case auth-key-explicit
            }  // choice ospfv3-auth-specification
          }  // case ospfv3-auth-trailer
        }  // choice auth-type-selection
      }  // container authentication
    }  // grouping interface-common-config

    grouping interface-config {
      description
        "Configuration for normal OSPF interfaces (not virtual
or sham interfaces).";
      leaf interface-type {
        type enumeration {
          enum "broadcast" {
            value 0;
            description
              "Specifies an OSPF broadcast multi-access network.";
          }
          enum "non-broadcast" {
            value 1;
            description
              "Specifies an OSPF Non-Broadcast Multi-Access
(NBMA) network.";
          }
          enum "point-to-multipoint" {
            value 2;
            description
              "Specifies an OSPF point-to-multipoint network.";
          }
          enum "point-to-point" {
            value 3;
            description
              "Specifies an OSPF point-to-point network.";
          }
          enum "hybrid" {
            value 4;
            description
              "Specifies an OSPF hybrid broadcast /
point-to-multipoint network.";
          }
        }
        description "Interface type.";
      }

      leaf passive {
        type boolean;
        description
          "Enables/disables a passive interface.  A passive
interface's prefix will be advertised, but no neighbor
adjacencies will be formed on the interface.";
      }

      leaf demand-circuit {
        if-feature demand-circuit;
        type boolean;
        description
          "Enables/disables a demand circuit.";
      }

      leaf priority {
        type uint8;
        description
          "Configures OSPF router priority.  In a multi-access
network, this value is for Designated Router (DR) election.
The priority is ignored on other interface types.  A router
with a higher priority will be preferred in the election.
A value of 0 indicates that the router is not eligible to
become the DR or Backup DR (BDR).";
      }

      container multi-areas {
        if-feature multi-area-adj;
        description
          "Container for multi-area configuration.";
        list multi-area {
          key "multi-area-id";
          description
            "Configures an OSPF multi-area adjacency.";
          leaf multi-area-id {
            type area-id-type;
            description
              "Multi-area adjacency area ID.";
          }

          leaf cost {
            type ospf-link-metric;
            description
              "Interface cost for a multi-area adjacency.";
          }
        }  // list multi-area
      }  // container multi-areas

      container static-neighbors {
        description
          "Statically configured neighbors.";
        list neighbor {
          key "identifier";
          description
            "Specifies a static OSPF neighbor.";
          leaf identifier {
            type inet:ip-address;
            description
              "Neighbor's Router ID, IPv4 address, or IPv6 address.";
          }

          leaf cost {
            type ospf-link-metric;
            description
              "Interface cost.  Different implementations have
different default costs, with some defaulting to a
cost inversely proportional to the interface speed.
Others will default to 1, equating the cost to a
hop count.";
          }

          leaf poll-interval {
            type uint16;
            units "seconds";
            description
              "Neighbor's poll interval (seconds) for sending OSPF
Hello packets to discover the neighbor on NBMA
networks.  This interval dictates the granularity for
discovery of new neighbors.  A sample would be
120 seconds (2 minutes) for a legacy Packet Data
Network (PDN) X.25 network.";
            reference
              "RFC 2328: OSPF Version 2, Appendix C.5";

          }

          leaf priority {
            type uint8;
            description
              "Neighbor's priority for DR election.  A router with a
higher priority will be preferred in the election.
A value of 0 indicates that the router is not
eligible to become the DR or BDR.";
          }
        }  // list neighbor
      }  // container static-neighbors

      leaf node-flag {
        if-feature node-flag;
        type boolean;
        default "false";
        description
          "Sets the prefix as identifying the advertising router.";
        reference
          "RFC 7684: OSPFv2 Prefix/Link Attribute Advertisement";

      }

      container bfd {
        if-feature bfd;
        description
          "BFD interface configuration.";
        reference
          "RFC 5880: Bidirectional Forwarding Detection (BFD)
           RFC 5881: Bidirectional Forwarding Detection
          (BFD) for IPv4 and IPv6 (Single Hop)
           RFC 9314: YANG Data Model for Bidirectional Forwarding
          Detection (BFD)";

        uses bfd-types:client-cfg-parms;
      }  // container bfd

      uses interface-fast-reroute-config;

      uses interface-common-config;

      uses interface-physical-link-config;
    }  // grouping interface-config

    grouping neighbor-state {
      description
        "OSPF neighbor operational state.";
      leaf address {
        type inet:ip-address;
        config false;
        description "Neighbor's address.";
      }

      leaf dr-router-id {
        type rt-types:router-id;
        config false;
        description
          "Neighbor's DR Router ID.";
      }

      leaf dr-ip-addr {
        type inet:ip-address;
        config false;
        description
          "Neighbor's DR IP address.";
      }

      leaf bdr-router-id {
        type rt-types:router-id;
        config false;
        description
          "Neighbor's BDR Router ID.";
      }

      leaf bdr-ip-addr {
        type inet:ip-address;
        config false;
        description
          "Neighbor's BDR IP address.";
      }

      leaf state {
        type nbr-state-type;
        config false;
        description "OSPF neighbor state.";
      }

      leaf cost {
        type ospf-link-metric;
        config false;
        description
          "Cost to reach the neighbor for point-to-multipoint
and Hybrid networks.";
      }

      leaf dead-timer {
        type rt-types:timer-value-seconds16;
        config false;
        description
          "This timer tracks the remaining time before
the neighbor is declared dead.";
      }

      container statistics {
        config false;
        description
          "Per-neighbor statistics.";
        uses neighbor-stat;
      }  // container statistics
    }  // grouping neighbor-state

    grouping interface-common-state {
      description
        "OSPF interface common operational state.";
      reference
        "RFC 2328: OSPF Version 2, Section 9";

      leaf state {
        type if-state-type;
        config false;
        description "Interface state.";
      }

      leaf hello-timer {
        type rt-types:timer-value-seconds16;
        config false;
        description
          "This timer tracks the remaining time before the
next Hello packet is sent on the interface.";
      }

      leaf wait-timer {
        type rt-types:timer-value-seconds16;
        config false;
        description
          "This timer tracks the remaining time before
the interface exits the 'Waiting' state.";
      }

      leaf dr-router-id {
        type rt-types:router-id;
        config false;
        description "DR Router ID.";
      }

      leaf dr-ip-addr {
        type inet:ip-address;
        config false;
        description "DR IP address.";
      }

      leaf bdr-router-id {
        type rt-types:router-id;
        config false;
        description "BDR Router ID.";
      }

      leaf bdr-ip-addr {
        type inet:ip-address;
        config false;
        description "BDR IP address.";
      }

      container statistics {
        config false;
        description
          "Per-interface statistics.";
        uses interface-stat;
      }  // container statistics

      container neighbors {
        config false;
        description
          "All neighbors for the interface.";
        list neighbor {
          key "neighbor-router-id";
          description
            "List of interface OSPF neighbors.";
          leaf neighbor-router-id {
            type rt-types:router-id;
            description
              "Neighbor's Router ID.";
          }

          uses neighbor-state;
        }  // list neighbor
      }  // container neighbors

      container database {
        config false;
        description "Link-scope LSDB.";
        list link-scope-lsa-type {
          key "lsa-type";
          description
            "List of OSPF link-scope LSAs.";
          leaf lsa-type {
            type uint16;
            description
              "OSPF link-scope LSA type.";
          }

          container link-scope-lsas {
            description
              "All link-scope LSAs of this LSA type.";
            list link-scope-lsa {
              key "lsa-id adv-router";
              description
                "List of OSPF link-scope LSAs.";
              uses lsa-key;

              uses lsa {
                refine 
                refine 
              }
            }  // list link-scope-lsa
          }  // container link-scope-lsas
        }  // list link-scope-lsa-type
      }  // container database
    }  // grouping interface-common-state

    grouping interface-state {
      description
        "OSPF interface operational state.";
      reference
        "RFC 2328: OSPF Version 2, Section 9";

      uses interface-common-state;
    }  // grouping interface-state

    grouping virtual-link-config {
      description
        "OSPF virtual link configuration state.";
      uses interface-common-config;
    }  // grouping virtual-link-config

    grouping virtual-link-state {
      description
        "OSPF virtual link operational state.";
      leaf cost {
        type ospf-link-metric;
        config false;
        description
          "Virtual link interface's cost.";
      }

      uses interface-common-state;
    }  // grouping virtual-link-state

    grouping sham-link-config {
      description
        "OSPF sham link configuration state.";
      uses interface-common-config;

      uses interface-physical-link-config;
    }  // grouping sham-link-config

    grouping sham-link-state {
      description
        "OSPF sham link operational state.";
      uses interface-common-state;
    }  // grouping sham-link-state

    grouping address-family-area-config {
      description
        "OSPF address-family-specific area configuration state.";
      container ranges {
        description
          "Container for summary ranges.";
        list range {
          key "prefix";
          description
            "Summarizes routes matching the address/mask.
Applicable to Area Border Routers (ABRs) only.";
          leaf prefix {
            type inet:ip-prefix;
            description
              "IPv4 or IPv6 prefix.";
          }

          leaf advertise {
            type boolean;
            description "Advertise or hide.";
          }

          leaf cost {
            type ospf-metric;
            description
              "Advertised cost of a summary route.";
          }
        }  // list range
      }  // container ranges
    }  // grouping address-family-area-config

    grouping area-common-config {
      description
        "OSPF area common configuration state.";
      leaf summary {
        when
          "derived-from(../area-type,'stub-nssa-area')" {
          description
            "Summary advertisement into the stub area or NSSA.";
        }
        type boolean;
        description
          "Enables/disables summary advertisement into the stub
area or NSSA.";
      }

      leaf default-cost {
        when
          "derived-from(../area-type,'stub-nssa-area')" {
          description
            "Cost for the LSA default route advertised into the
stub area or NSSA.";
        }
        type ospf-metric;
        description
          "Sets the summary default route cost for a stub area
or NSSA.";
      }
    }  // grouping area-common-config

    grouping area-config {
      description
        "OSPF area configuration state.";
      leaf area-type {
        type identityref {
          base area-type;
        }
        default "normal-area";
        description "Area type.";
      }

      uses area-common-config;

      uses address-family-area-config;
    }  // grouping area-config

    grouping area-state {
      description
        "OSPF area operational state.";
      container statistics {
        config false;
        description "Per-area statistics.";
        uses area-stat;
      }  // container statistics

      container database {
        config false;
        description "Area-scope LSDB.";
        list area-scope-lsa-type {
          key "lsa-type";
          description
            "List of OSPF area-scope LSAs.";
          leaf lsa-type {
            type uint16;
            description
              "OSPF area-scope LSA type.";
          }

          container area-scope-lsas {
            description
              "All area-scope LSAs.";
            list area-scope-lsa {
              key "lsa-id adv-router";
              description
                "List of OSPF area-scope LSAs.";
              uses lsa-key;

              uses lsa {
                refine 
                refine 
              }
            }  // list area-scope-lsa
          }  // container area-scope-lsas
        }  // list area-scope-lsa-type
      }  // container database
    }  // grouping area-state

    grouping local-rib {
      description
        "Local RIB.  RIB for routes computed by the local
OSPF routing instance.";
      container local-rib {
        config false;
        description "Local RIB.";
        list route {
          key "prefix";
          description
            "OSPF instance's Local Routes.";
          leaf prefix {
            type inet:ip-prefix;
            description
              "Destination prefix.";
          }

          container next-hops {
            description
              "Next hops for the route.";
            list next-hop {
              description
                "List of next hops for the route.";
              leaf outgoing-interface {
                type if:interface-ref;
                description
                  "Name of the outgoing interface.";
              }

              leaf next-hop {
                type inet:ip-address;
                description
                  "Address of the next hop.";
              }
            }  // list next-hop
          }  // container next-hops

          leaf metric {
            type uint32;
            description
              "Metric for this route.";
          }

          leaf route-type {
            type route-type;
            description
              "Route type for this route.";
          }

          leaf route-tag {
            type uint32;
            description
              "Route tag for this route.";
          }
        }  // list route
      }  // container local-rib
    }  // grouping local-rib

    grouping ietf-spf-delay {
      description
        "Grouping for IETF SPF delay configuration and state.";
      reference
        "RFC 8405: Shortest Path First (SPF) Back-Off Delay Algorithm
        for Link-State IGPs";

      leaf initial-delay {
        type uint32;
        units "milliseconds";
        default "50";
        description
          "Delay used while in the 'QUIET' state (milliseconds).";
      }

      leaf short-delay {
        type uint32;
        units "milliseconds";
        default "200";
        description
          "Delay used while in the 'SHORT_WAIT' state (milliseconds).";
      }

      leaf long-delay {
        type uint32;
        units "milliseconds";
        default "5000";
        description
          "Delay used while in the 'LONG_WAIT' state (milliseconds).";
      }

      leaf hold-down {
        type uint32;
        units "milliseconds";
        default "10000";
        description
          "This timer value defines the period without any changes
for the IGP to be considered stable (milliseconds).";
      }

      leaf time-to-learn {
        type uint32;
        units "milliseconds";
        default "500";
        description
          "Duration used to learn all the IGP events
related to a single network event (milliseconds).";
      }

      leaf current-state {
        type enumeration {
          enum "quiet" {
            value 0;
            description "'QUIET' state.";
          }
          enum "short-wait" {
            value 1;
            description
              "'SHORT_WAIT' state.";
          }
          enum "long-wait" {
            value 2;
            description "'LONG_WAIT' state.";
          }
        }
        config false;
        description
          "Current SPF back-off algorithm state.";
      }

      leaf remaining-time-to-learn {
        type rt-types:timer-value-milliseconds;
        config false;
        description
          "Remaining time until the time-to-learn timer fires.";
      }

      leaf remaining-hold-down {
        type rt-types:timer-value-milliseconds;
        config false;
        description
          "Remaining time until the hold-down timer fires.";
      }

      leaf last-event-received {
        type yang:timestamp;
        config false;
        description
          "Time of the last SPF triggering event.";
      }

      leaf next-spf-time {
        type yang:timestamp;
        config false;
        description
          "Time when the next SPF has been scheduled.";
      }

      leaf last-spf-time {
        type yang:timestamp;
        config false;
        description
          "Time of the last SPF computation.";
      }
    }  // grouping ietf-spf-delay

    grouping node-tag-config {
      description
        "OSPF node tag configuration state.";
      container node-tags {
        if-feature node-tag;
        description
          "Container for node administrative tags.";
        list node-tag {
          key "tag";
          description "List of node tags.";
          leaf tag {
            type uint32;
            description "Node tag value.";
          }
        }  // list node-tag
      }  // container node-tags
    }  // grouping node-tag-config

    grouping instance-config {
      description
        "OSPF instance configuration state.";
      leaf enabled {
        type boolean;
        default "true";
        description
          "Enables/disables the protocol.";
      }

      leaf explicit-router-id {
        if-feature explicit-router-id;
        type rt-types:router-id;
        description
          "Defined in RFC 2328.  A 32-bit number
that uniquely identifies the router.";
        reference
          "RFC 2328: OSPF Version 2";

      }

      container preference {
        description
          "Route preference configuration.  In many
implementations, preference is referred to as
administrative distance.";
        reference
          "RFC 8349: A YANG Data Model for Routing Management
          (NMDA Version)";

        choice scope {
          description
            "Options for expressing preference
as single or multiple values.";
          leaf all {
            type uint8;
            description
              "Preference for intra-area, inter-area, and
external routes.";
          }

          case multi-values {
            choice granularity {
              description
                "Options for expressing preference
for intra-area and inter-area routes.";
              case detail {
                leaf intra-area {
                  type uint8;
                  description
                    "Preference for intra-area routes.";
                }

                leaf inter-area {
                  type uint8;
                  description
                    "Preference for inter-area routes.";
                }
              }  // case detail
              leaf internal {
                type uint8;
                description
                  "Preference for both intra-area and
inter-area routes.";
              }
            }  // choice granularity

            leaf external {
              type uint8;
              description
                "Preference for AS external and NSSA routes.";
            }
          }  // case multi-values
        }  // choice scope
      }  // container preference

      container nsr {
        if-feature nsr;
        description
          "Non-Stop Routing (NSR) configuration state.";
        leaf enabled {
          type boolean;
          description
            "Enables/disables NSR.";
        }
      }  // container nsr

      container graceful-restart {
        if-feature graceful-restart;
        description
          "Graceful restart configuration state.";
        reference
          "RFC 3623: Graceful OSPF Restart
           RFC 5187: OSPFv3 Graceful Restart";

        leaf enabled {
          type boolean;
          description
            "Enables/disables graceful restart as defined in RFC 3623
for OSPFv2 and RFC 5187 for OSPFv3.";
        }

        leaf helper-enabled {
          type boolean;
          description
            "Enables graceful restart helper support for restarting
routers (Section 3 of RFC 3623).";
          reference
            "RFC 3623: Graceful OSPF Restart, Section 3";

        }

        leaf restart-interval {
          type uint16 {
            range "1..1800";
          }
          units "seconds";
          default "120";
          description
            "Interval during which to attempt graceful restart prior
to failing (seconds) (Appendix B.1 of RFC 3623).";
          reference
            "RFC 3623: Graceful OSPF Restart, Appendix B.1";

        }

        leaf helper-strict-lsa-checking {
          type boolean;
          description
            "Terminates graceful restart when an LSA topology change
is detected (Appendix B.2 of RFC 3623).";
          reference
            "RFC 3623: Graceful OSPF Restart, Appendix B.2";

        }
      }  // container graceful-restart

      container auto-cost {
        if-feature auto-cost;
        description
          "Interface auto-cost configuration state.";
        leaf enabled {
          type boolean;
          description
            "Enables/disables interface auto-cost.";
        }

        leaf reference-bandwidth {
          when "../enabled = 'true'" {
            description
              "Only when auto-cost is enabled.";
          }
          type uint32 {
            range "1..4294967";
          }
          units "Mbits";
          description
            "Configures reference bandwidth used to automatically
determine interface cost (Mbits).  The cost is the
reference bandwidth divided by the interface speed,
with 1 being the minimum cost.";
        }
      }  // container auto-cost

      container spf-control {
        description
          "SPF calculation control.";
        leaf paths {
          if-feature max-ecmp;
          type uint16 {
            range "1..65535";
          }
          description
            "Maximum number of Equal-Cost Multi-Path (ECMP) paths.";
        }

        container ietf-spf-delay {
          if-feature ietf-spf-delay;
          description
            "IETF SPF delay algorithm configuration.";
          uses ietf-spf-delay;
        }  // container ietf-spf-delay
      }  // container spf-control

      container database-control {
        description
          "Database maintenance control.";
        leaf max-lsa {
          if-feature max-lsa;
          type uint32 {
            range "1..4294967294";
          }
          description
            "Maximum number of OSPF LSAs the router will accept.";
        }
      }  // container database-control

      container stub-router {
        if-feature stub-router;
        description
          "Sets the maximum metric configuration.";
        choice trigger {
          description
            "Specific triggers that will enable stub router state.";
          container always {
            presence
              "Enables unconditional stub router support";
            description
              "Unconditional stub router state (advertises
transit links with 'MaxLinkMetric').";
            reference
              "RFC 6987: OSPF Stub Router Advertisement";

          }  // container always
        }  // choice trigger
      }  // container stub-router

      container mpls {
        description
          "OSPF MPLS configuration state.";
        container te-rid {
          if-feature te-rid;
          description
            "Stable OSPF Router IP address used for TE.";
          leaf ipv4-router-id {
            type inet:ipv4-address;
            description
              "Explicitly configures a TE IPv4 Router ID.";
          }

          leaf ipv6-router-id {
            type inet:ipv6-address;
            description
              "Explicitly configures a TE IPv6 Router ID.";
          }
        }  // container te-rid

        container ldp {
          description
            "OSPF MPLS LDP configuration state.";
          leaf igp-sync {
            if-feature ldp-igp-sync;
            type boolean;
            description
              "Enables LDP IGP synchronization.";
          }
        }  // container ldp
      }  // container mpls

      uses instance-fast-reroute-config;

      uses node-tag-config;
    }  // grouping instance-config

    grouping instance-state {
      description
        "OSPF instance operational state.";
      leaf router-id {
        type rt-types:router-id;
        config false;
        description
          "Defined in RFC 2328.  A 32-bit number
that uniquely identifies the router.";
        reference
          "RFC 2328: OSPF Version 2";

      }

      uses local-rib;

      container statistics {
        config false;
        description
          "Per-instance statistics.";
        uses instance-stat;
      }  // container statistics

      container database {
        config false;
        description "AS-Scope LSDB.";
        list as-scope-lsa-type {
          key "lsa-type";
          description
            "List of OSPF AS-Scope LSAs.";
          leaf lsa-type {
            type uint16;
            description
              "OSPF AS-Scope LSA type.";
          }

          container as-scope-lsas {
            description
              "All AS-Scope LSAs of this LSA type.";
            list as-scope-lsa {
              key "lsa-id adv-router";
              description
                "List of OSPF AS-Scope LSAs.";
              uses lsa-key;

              uses lsa {
                refine 
                refine 
              }
            }  // list as-scope-lsa
          }  // container as-scope-lsas
        }  // list as-scope-lsa-type
      }  // container database

      uses spf-log;

      uses lsa-log;
    }  // grouping instance-state

    grouping multi-topology-area-common-config {
      description
        "OSPF multi-topology area common configuration state.";
      leaf summary {
        when
          "derived-from(../../../area-type, 'stub-nssa-area')" {
          description
            "Summary advertisement into the stub area or NSSA.";
        }
        type boolean;
        description
          "Enables/disables a summary advertisement into the
topology in the stub area or NSSA.";
      }

      leaf default-cost {
        when
          "derived-from(../../../area-type, 'stub-nssa-area')" {
          description
            "Cost for the LSA default route advertised into the
topology in the stub area or NSSA.";
        }
        type ospf-metric;
        description
          "Sets the summary default route cost for a
stub area or NSSA.";
      }
    }  // grouping multi-topology-area-common-config

    grouping multi-topology-area-config {
      description
        "OSPF multi-topology area configuration state.";
      uses multi-topology-area-common-config;

      uses address-family-area-config;
    }  // grouping multi-topology-area-config

    grouping multi-topology-state {
      description
        "OSPF multi-topology operational state.";
      uses local-rib;
    }  // grouping multi-topology-state

    grouping multi-topology-interface-config {
      description
        "OSPF multi-topology configuration state.";
      leaf cost {
        type ospf-link-metric;
        description
          "Interface cost for this topology.";
      }
    }  // grouping multi-topology-interface-config

    grouping ospfv3-interface-config {
      description
        "OSPFv3 interface-specific configuration state.";
      leaf instance-id {
        type uint8;
        default "0";
        description "OSPFv3 instance ID.";
      }
    }  // grouping ospfv3-interface-config

    grouping ospfv3-interface-state {
      description
        "OSPFv3 interface-specific operational state.";
      leaf interface-id {
        type uint32;
        config false;
        description "OSPFv3 interface ID.";
      }
    }  // grouping ospfv3-interface-state

    grouping lsa-identifiers {
      description
        "The parameters that uniquely identify an LSA.";
      leaf area-id {
        type area-id-type;
        description "Area ID.";
      }

      leaf type {
        type uint16;
        description "LSA type.";
      }

      leaf lsa-id {
        type union {
          type inet:ipv4-address;
          type yang:dotted-quad;
        }
        description "Link State ID.";
      }

      leaf adv-router {
        type rt-types:router-id;
        description
          "LSA advertising router.";
      }

      leaf seq-num {
        type uint32;
        description "LSA sequence number.";
      }
    }  // grouping lsa-identifiers

    grouping spf-log {
      description
        "Grouping for the SPF log.";
      container spf-log {
        config false;
        description
          "This container lists the SPF log entries.";
        list event {
          key "id";
          description
            "List of SPF log entries represented
as a wrapping buffer in chronological
order, with the oldest entry returned
first.";
          leaf id {
            type uint32;
            description
              "Event identifier.  A purely internal value.";
          }

          leaf spf-type {
            type enumeration {
              enum "full" {
                value 0;
                description
                  "The SPF computation was for a full SPF.";
              }
              enum "intra" {
                value 1;
                description
                  "The SPF computation was only for intra-area
routes.";
              }
              enum "inter" {
                value 2;
                description
                  "The SPF computation was only for inter-area
summary routes.";
              }
              enum "external" {
                value 3;
                description
                  "The SPF computation was only for AS external
and NSSA routes.";
              }
            }
            description
              "The SPF computation type for the SPF log entry.";
          }

          leaf schedule-timestamp {
            type yang:timestamp;
            description
              "This is the timestamp when the computation was
scheduled.";
          }

          leaf start-timestamp {
            type yang:timestamp;
            description
              "This is the timestamp when the computation was
started.";
          }

          leaf end-timestamp {
            type yang:timestamp;
            description
              "This is the timestamp when the computation was
completed.";
          }

          list trigger-lsa {
            description
              "The list of LSAs that triggered the computation.";
            uses lsa-identifiers;
          }  // list trigger-lsa
        }  // list event
      }  // container spf-log
    }  // grouping spf-log

    grouping lsa-log {
      description
        "Grouping for the LSA log.";
      container lsa-log {
        config false;
        description
          "This container lists the LSA log entries.
Local LSA modifications are also included
in the list.";
        list event {
          key "id";
          description
            "List of LSA log entries represented
as a wrapping buffer in chronological order,
with the oldest entry returned first.";
          leaf id {
            type uint32;
            description
              "Event identifier.  A purely internal value.";
          }

          container lsa {
            description
              "This container describes the LSA that was logged.";
            uses lsa-identifiers;
          }  // container lsa

          leaf received-timestamp {
            type yang:timestamp;
            description
              "This is the timestamp when the LSA was received.
In the case of a local LSA update, the timestamp
refers to the LSA origination time.";
          }

          leaf reason {
            type identityref {
              base lsa-log-reason;
            }
            description
              "Reason for the LSA log entry.";
          }
        }  // list event
      }  // container lsa-log
    }  // grouping lsa-log

    augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol {
      when "derived-from(rt:type, 'ospf')" {
        description
          "This augmentation is only valid for a routing protocol
instance of OSPF (type 'ospfv2' or 'ospfv3').";
      }
      description
        "OSPF protocol 'ietf-routing' module 'control-plane-protocol'
augmentation.";
      container ospf {
        description
          "OSPF protocol instance.";
        leaf address-family {
          when
            "derived-from-or-self(../../rt:type, 'ospfv3')" {
            description
              "Only applicable to OSPFv3.";
          }
          type iana-rt-types:address-family;
          description
            "Address family of the instance.";
        }

        uses instance-config;

        uses instance-state;

        container areas {
          description "All OSPF areas.";
          list area {
            key "area-id";
            description
              "List of OSPF areas.";
            leaf area-id {
              type area-id-type;
              description "Area ID.";
            }

            uses area-config;

            uses area-state;

            container virtual-links {
              when
                "derived-from-or-self(../area-type, 'normal-area') and ../area-id = '0.0.0.0'" {
                description
                  "Virtual links must be in a backbone area.";
              }
              description
                "All virtual links.";
              list virtual-link {
                key "transit-area-id router-id";
                description
                  "OSPF virtual link.";
                leaf transit-area-id {
                  type leafref {
                    path
                      "../../../../area/area-id";
                  }
                  must
                    "derived-from-or-self(../../../../area[area-id=current()]/area-type, 'normal-area') and ../../../../area[area-id=current()]/area-id != '0.0.0.0'" {
                    error-message
                      "The virtual link transit area must not be the backbone area.";
                    description
                      "The virtual link transit area must not be the
backbone area (0.0.0.0).";
                  }
                  description
                    "Virtual link transit area ID.";
                }

                leaf router-id {
                  type rt-types:router-id;
                  description
                    "Virtual link remote endpoint Router ID.";
                }

                uses virtual-link-config;

                uses virtual-link-state;
              }  // list virtual-link
            }  // container virtual-links

            container sham-links {
              if-feature pe-ce-protocol;
              description "All sham links.";
              list sham-link {
                key "local-id remote-id";
                description
                  "OSPF sham link.";
                leaf local-id {
                  type inet:ip-address;
                  description
                    "Address of the local sham link endpoint.";
                }

                leaf remote-id {
                  type inet:ip-address;
                  description
                    "Address of the remote sham link endpoint.";
                }

                uses sham-link-config;

                uses sham-link-state;
              }  // list sham-link
            }  // container sham-links

            container interfaces {
              description
                "All OSPF interfaces.";
              list interface {
                key "name";
                description
                  "List of OSPF interfaces.";
                leaf name {
                  type if:interface-ref;
                  description
                    "Interface name reference.";
                }

                uses interface-config;

                uses interface-state;
              }  // list interface
            }  // container interfaces
          }  // list area
        }  // container areas
      }  // container ospf
    }

    augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/ospf {
      when
        "derived-from(../rt:type, 'ospf')" {
        description
          "This augmentation is only valid for OSPF
(type 'ospfv2' or 'ospfv3').";
      }
      if-feature multi-topology;
      description
        "OSPF multi-topology instance configuration
state augmentation.";
      container topologies {
        description "All topologies.";
        list topology {
          key "name";
          description
            "OSPF topology.  The OSPF topology address family
must coincide with the routing instance's
address family.";
          leaf name {
            type leafref {
              path
                "../../../../../../rt:ribs/rt:rib/rt:name";
            }
            description
              "RIB name corresponding to the OSPF topology.";
          }

          uses multi-topology-state;
        }  // list topology
      }  // container topologies
    }

    augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/ospf/areas/area {
      when
        "derived-from-or-self(../../../rt:type, 'ospfv2')" {
        description
          "This augmentation is only valid for OSPFv2.";
      }
      if-feature multi-topology;
      description
        "OSPF multi-topology area configuration state
augmentation.";
      container topologies {
        description
          "All topologies for the area.";
        list topology {
          key "name";
          description "OSPF area topology.";
          leaf name {
            type leafref {
              path
                "../../../../../../../../rt:ribs/rt:rib/rt:name";
            }
            description
              "Single topology enabled for this area.";
          }

          uses multi-topology-area-config;
        }  // list topology
      }  // container topologies
    }

    augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/ospf/areas/area/interfaces/interface {
      when
        "derived-from-or-self(../../../../../rt:type, 'ospfv2')" {
        description
          "This augmentation is only valid for OSPFv2.";
      }
      if-feature multi-topology;
      description
        "OSPF multi-topology interface configuration state
augmentation.";
      container topologies {
        description
          "All topologies for the interface.";
        list topology {
          key "name";
          description
            "OSPF interface topology.";
          leaf name {
            type leafref {
              path
                "../../../../../../../../../../rt:ribs/rt:rib/rt:name";
            }
            description
              "Single topology enabled on this interface.";
          }

          uses multi-topology-interface-config;
        }  // list topology
      }  // container topologies
    }

    augment /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/ospf/areas/area/interfaces/interface {
      when
        "derived-from-or-self(../../../../../rt:type, 'ospfv3')" {
        description
          "This augmentation is only valid for OSPFv3.";
      }
      description
        "OSPFv3 interface-specific configuration state
augmentation.";
      uses ospfv3-interface-config;

      uses ospfv3-interface-state;
    }

    grouping route-content {
      description
        "This grouping defines OSPF-specific route attributes.";
      leaf metric {
        type uint32;
        description "OSPF route metric.";
      }

      leaf tag {
        type uint32;
        default "0";
        description "OSPF route tag.";
      }

      leaf route-type {
        type route-type;
        description "OSPF route type.";
      }
    }  // grouping route-content

    augment /rt:routing/rt:ribs/rt:rib/rt:routes/rt:route {
      when
        "derived-from(rt:source-protocol, 'ospf')" {
        description
          "This augmentation is only valid for routes whose
source protocol is OSPF.";
      }
      description
        "OSPF-specific route attributes.";
      uses route-content;
    }

    rpc clear-neighbor {
      description
        "This RPC request clears a particular set of OSPF neighbors.
If the operation fails for an OSPF-internal reason, then
'error-tag' and 'error-app-tag' should be set to values
indicating the error.";
      input {
        leaf routing-protocol-name {
          type leafref {
            path "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/rt:name";
          }
          mandatory true;
          description
            "OSPF protocol instance for which information for neighbors
is to be cleared.

If the referenced OSPF instance doesn't exist, then
this operation SHALL fail with an 'error-tag' setting of
'data-missing' and an 'error-app-tag' setting of
'routing-protocol-instance-not-found'.";
        }

        leaf interface {
          type if:interface-ref;
          description
            "Name of the OSPF interface for which neighbors are to
be cleared.

If the referenced OSPF interface doesn't exist, then
this operation SHALL fail with an 'error-tag' setting
of 'data-missing' and an 'error-app-tag' setting of
'ospf-interface-not-found'.";
        }
      }
    }  // rpc clear-neighbor

    rpc clear-database {
      description
        "This RPC request clears a particular OSPF Link State
Database.  Additionally, all neighbor adjacencies will
be forced to the DOWN state and self-originated LSAs
will be reoriginated.  If the operation fails for an
OSPF-internal reason, then 'error-tag' and 'error-app-tag'
should be set to values indicating the error.";
      input {
        leaf routing-protocol-name {
          type leafref {
            path "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/rt:name";
          }
          mandatory true;
          description
            "OSPF protocol instance whose LSDB is to be cleared.

If the referenced OSPF instance doesn't exist, then
this operation SHALL fail with an 'error-tag' setting of
'data-missing' and an 'error-app-tag' setting of
'routing-protocol-instance-not-found'.";
        }
      }
    }  // rpc clear-database

    grouping notification-instance-hdr {
      description
        "This grouping describes common instance-specific
data for OSPF notifications.";
      leaf routing-protocol-name {
        type leafref {
          path
            "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol/rt:name";
        }
        must
          "derived-from( /rt:routing/rt:control-plane-protocols/rt:control-plane-protocol[rt:name=current()]/rt:type, 'ospf')";
        description
          "Name of the OSPF routing protocol instance.";
      }

      leaf address-family {
        type leafref {
          path
            "/rt:routing/rt:control-plane-protocols/rt:control-plane-protocol[rt:name=current()/../routing-protocol-name]/ospf/address-family";
        }
        description
          "Address family of the OSPF instance.";
      }
    }  // grouping notification-instance-hdr

    grouping notification-interface {
      description
        "This grouping provides interface information
for OSPF interface-specific notifications.";
      choice if-link-type-selection {
        description
          "Options for link types.";
        container interface {
          description "Normal interface.";
          leaf interface {
            type if:interface-ref;
            description "Interface.";
          }
        }  // container interface
        container virtual-link {
          description "Virtual link.";
          leaf transit-area-id {
            type area-id-type;
            description "Area ID.";
          }

          leaf neighbor-router-id {
            type rt-types:router-id;
            description
              "Neighbor's Router ID.";
          }
        }  // container virtual-link
        container sham-link {
          description "Sham link.";
          leaf area-id {
            type area-id-type;
            description "Area ID.";
          }

          leaf local-ip-addr {
            type inet:ip-address;
            description
              "Sham link's local address.";
          }

          leaf remote-ip-addr {
            type inet:ip-address;
            description
              "Sham link's remote address.";
          }
        }  // container sham-link
      }  // choice if-link-type-selection
    }  // grouping notification-interface

    grouping notification-neighbor {
      description
        "This grouping provides the neighbor information
for neighbor-specific notifications.";
      leaf neighbor-router-id {
        type rt-types:router-id;
        description "Neighbor's Router ID.";
      }

      leaf neighbor-ip-addr {
        type inet:ip-address;
        description "Neighbor's address.";
      }
    }  // grouping notification-neighbor

    notification if-state-change {
      description
        "This notification is sent when an interface
state change is detected.";
      uses notification-instance-hdr;

      uses notification-interface;

      leaf state {
        type if-state-type;
        description "Interface state.";
      }
    }  // notification if-state-change

    notification if-config-error {
      description
        "This notification is sent when a packet is received indicating
an interface configuration error on the sending OSPF router.";
      uses notification-instance-hdr;

      uses notification-interface;

      leaf packet-source {
        type inet:ip-address;
        description "Source address.";
      }

      leaf packet-type {
        type packet-type;
        description "OSPF packet type.";
      }

      leaf error {
        type enumeration {
          enum "bad-version" {
            value 0;
            description "Bad version.";
          }
          enum "area-mismatch" {
            value 1;
            description "Area mismatch.";
          }
          enum "unknown-nbma-nbr" {
            value 2;
            description
              "Unknown NBMA neighbor.";
          }
          enum "unknown-virtual-nbr" {
            value 3;
            description
              "Unknown virtual link neighbor.";
          }
          enum "auth-type-mismatch" {
            value 4;
            description
              "Authentication type mismatch.";
          }
          enum "auth-failure" {
            value 5;
            description
              "Authentication failure.";
          }
          enum "net-mask-mismatch" {
            value 6;
            description
              "Network mask mismatch.";
          }
          enum "hello-interval-mismatch" {
            value 7;
            description
              "Hello interval mismatch.";
          }
          enum "dead-interval-mismatch" {
            value 8;
            description
              "Dead interval mismatch.";
          }
          enum "option-mismatch" {
            value 9;
            description "Option mismatch.";
          }
          enum "mtu-mismatch" {
            value 10;
            description "MTU mismatch.";
          }
          enum "duplicate-router-id" {
            value 11;
            description
              "Duplicate Router ID.";
          }
          enum "no-error" {
            value 12;
            description "No error.";
          }
        }
        description "Error codes.";
      }
    }  // notification if-config-error

    notification nbr-state-change {
      description
        "This notification is sent when a neighbor
state change is detected.";
      uses notification-instance-hdr;

      uses notification-interface;

      uses notification-neighbor;

      leaf state {
        type nbr-state-type;
        description "Neighbor state.";
      }
    }  // notification nbr-state-change

    notification nbr-restart-helper-status-change {
      description
        "This notification is sent when a neighbor restart
helper status change is detected.";
      uses notification-instance-hdr;

      uses notification-interface;

      uses notification-neighbor;

      leaf status {
        type restart-helper-status-type;
        description "Restart helper status.";
      }

      leaf age {
        type rt-types:timer-value-seconds16;
        description
          "Remaining time in the current OSPF graceful restart
interval when the router is acting as a restart
helper for the neighbor.";
      }

      leaf exit-reason {
        type restart-exit-reason-type;
        description
          "Restart helper exit reason.";
      }
    }  // notification nbr-restart-helper-status-change

    notification if-rx-bad-packet {
      description
        "This notification is sent when an OSPF packet that
cannot be parsed is received on an OSPF interface.";
      uses notification-instance-hdr;

      uses notification-interface;

      leaf packet-source {
        type inet:ip-address;
        description "Source address.";
      }

      leaf packet-type {
        type packet-type;
        description "OSPF packet type.";
      }
    }  // notification if-rx-bad-packet

    notification lsdb-approaching-overflow {
      description
        "This notification is sent when the number of LSAs
in the router's LSDB has exceeded ninety percent of the
AS-External-LSA limit ('ext-lsdb-limit').";
      uses notification-instance-hdr;

      leaf ext-lsdb-limit {
        type uint32;
        description
          "The maximum number of non-default AS-External-LSA
entries that can be stored in the LSDB.";
      }
    }  // notification lsdb-approaching-overflow

    notification lsdb-overflow {
      description
        "This notification is sent when the number of LSAs
in the router's LSDB has exceeded the AS-External-LSA limit
('ext-lsdb-limit').";
      uses notification-instance-hdr;

      leaf ext-lsdb-limit {
        type uint32;
        description
          "The maximum number of non-default AS-External-LSA
entries that can be stored in the LSDB.";
      }
    }  // notification lsdb-overflow

    notification nssa-translator-status-change {
      description
        "This notification is sent when there is a change
in the router's role in translating OSPF NSSA-LSAs
to OSPF AS-External-LSAs.";
      uses notification-instance-hdr;

      leaf area-id {
        type area-id-type;
        description "Area ID.";
      }

      leaf status {
        type nssa-translator-state-type;
        description
          "NSSA translator status.";
      }
    }  // notification nssa-translator-status-change

    notification restart-status-change {
      description
        "This notification is sent when the graceful restart
state for the router has changed.";
      uses notification-instance-hdr;

      leaf status {
        type restart-status-type;
        description "Restart status.";
      }

      leaf restart-interval {
        type uint16 {
          range "1..1800";
        }
        units "seconds";
        default "120";
        description "Restart interval.";
      }

      leaf exit-reason {
        type restart-exit-reason-type;
        description "Restart exit reason.";
      }
    }  // notification restart-status-change
  }  // module ietf-ospf