module l3-unicast-igp-topology {
    yang-version 1;
    namespace "urn:TBD:params:xml:ns:yang:nt:l3-unicast-igp-topology";
    // replace with IANA namespace when assigned
    prefix "l3t";
    import network-topology {
        prefix "nt";
        revision-date 2013-10-21;
    }

    import ietf-inet-types {
        prefix "inet";
        revision-date 2013-07-15;
    }

    organization "TBD";
    contact "TBD";

    revision "2013-10-21" {
        description "Initial revision";
        reference "TBD";
    }

    typedef igp-event-type {
        description "IGP Event type for notifications";
            type enumeration {
                enum "add" {
                    value 0;
                        description "An IGP node or link or prefix or termination-point has been added";
                }
                enum "remove" {
                    value 1;
                    description "An IGP node or link or prefix or termination-point has been removed";
                }
                enum "update" {
                    value 2;
                    description "An IGP node or link or prefix or termination-point has been updated";
                }
            }
        } // igp-event-type

    identity flag-identity {
        description "Base type for flags";
    }
    identity undefined-flag {
        base "flag-identity";
    }

    typedef flag-type {

        type identityref {
            base "flag-identity";
        }
    }

    grouping igp-prefix-attributes {
        leaf prefix {
            type inet:ip-prefix;
        }
        leaf metric {
            type uint32;
        }
        leaf-list flag {
            type flag-type;
        }
    }

    grouping l3-unicast-igp-topology-type {
        container l3-unicast-igp-topology {
            presence "indicates L3 Unicast IGP Topology";
        }
    }

    grouping igp-topology-attributes {
        container igp-topology-attributes {
            leaf name {
                description "Name of the topology";
                    type string;
            }
            leaf-list flag {
                description "Topology flags";
                type flag-type;
            }
        }
    }

    grouping igp-node-attributes {
        container igp-node-attributes {
            leaf name {
                description "Node name";
                type inet:domain-name;
            }
            leaf-list flag {
                description "Node operational flags";
                type flag-type;
            }
            leaf-list router-id {
                description "Router-id for the node";

                type inet:ip-address;
            }
            list prefix {
                key "prefix";
                uses igp-prefix-attributes;
            }
        }
    }

    grouping igp-link-attributes {
        container igp-link-attributes {
            leaf name {
                description "Link Name";
                type string;
            }
            leaf-list flag {
                description "Link flags";
                type flag-type;
            }
            leaf metric {
                description "Link Metric";
                type uint32 {
                    range "0..16777215"  {
                        description "
                        ";
                        // OSPF/ISIS supports max 3 byte metric.
                        // Ideally we would like this restriction to be
                        // defined in the derived models, however,
                        // we are not allowed to augment a "must" statement.
                    }
                }
            }
        }
    } // grouping igp-link-attributes

    grouping igp-termination-point-attributes {
        container igp-termination-point-attributes {
            choice termination-point-type {
                case ip {
                   leaf-list ip-address {
                    description "IPv4 or IPv6 address";
                    type inet:ip-address;
                    }
                }
                case unnumbered {
                    leaf unnumbered-id {
                    description "Unnumbered interface identifier";
                    type uint32;

                    }
                }
            }
        }
    } // grouping igp-termination-point-attributes


    augment "/nt:network-topology/nt:topology/nt:topology-types" {
        uses l3-unicast-igp-topology-type;
    }

    augment "/nt:network-topology/nt:topology" {
        when "nt:topology-types/l3-unicast-igp-topology";
        uses igp-topology-attributes;
    }

    augment "/nt:network-topology/nt:topology/nt:node" {
        when "../nt:topology-types/l3-unicast-igp-topology";
        uses igp-node-attributes;
    }
    augment "/nt:network-topology/nt:topology/nt:link" {
        when "../nt:topology-types/l3-unicast-igp-topology";
        uses igp-link-attributes;
    }
    augment "/nt:network-topology/nt:topology/nt:node/nt:termination-point" {
        when "../../nt:topology-types/l3-unicast-igp-topology";
        uses igp-termination-point-attributes;
    }

    notification igp-node-event {
        leaf igp-event-type {
            type igp-event-type;
        }
        leaf topology-ref {
            type nt:topology-ref;
        }
        uses l3-unicast-igp-topology-type;
        uses nt:node-attributes;
        uses igp-node-attributes;
    }

    notification igp-link-event {
        leaf igp-event-type {
            type igp-event-type;
        }
        leaf topology-ref {
            type nt:topology-ref;
        }

        uses l3-unicast-igp-topology-type;
        uses nt:link-attributes;
        uses igp-link-attributes;
    }

    notification igp-prefix-event {
        leaf igp-event-type {
            type igp-event-type;
        }
        leaf topology-ref {
            type nt:topology-ref;
        }
        leaf node-ref {
            type nt:node-ref;
        }
        uses l3-unicast-igp-topology-type;
        container prefix {
            uses igp-prefix-attributes;
        }
    }

    notification termination-point-event {
        leaf igp-event-type {
            type igp-event-type;
        }
        leaf topology-ref {
            type nt:topology-ref;
        }
        leaf node-ref {
            type nt:node-ref;
        }
        uses l3-unicast-igp-topology-type;
        uses nt:tp-attributes;
        uses igp-termination-point-attributes;
    }
}