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Versions: 00 01

NETMOD Working Group                                             M. Wang
Internet-Draft                                                     Q. Wu
Intended status: Standards Track                                  Huawei
Expires: September 2, 2019                                        C. Xie
                                                           China Telecom
                                                           March 1, 2019


          A YANG Data model for Policy based Event Management
                     draft-wwx-netmod-event-yang-01

Abstract

   [RFC8328] defines a policy-based management framework that allow
   definition of a data model to be used to represent high-level,
   possibly network-wide policies.  This document defines an YANG data
   model for the policy based event management [RFC7950].  The policy
   based Event YANG provides the ability for the network management
   function (within a controller, an orchestrator, or a network element)
   to control the configuration and monitor state change on the network
   element and take simple and instant action when a trigger condition
   on the system state is met.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 2, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   2
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     2.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Relationship to YANG Push . . . . . . . . . . . . . . . . . .   4
   5.  Relationship to EVENT MIB . . . . . . . . . . . . . . . . . .   5
   6.  Model Overview  . . . . . . . . . . . . . . . . . . . . . . .   6
   7.  EVENT TRIGGER YANG Module . . . . . . . . . . . . . . . . . .  10
   8.  EVENT YANG Module . . . . . . . . . . . . . . . . . . . . . .  14
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
   11. Normative References  . . . . . . . . . . . . . . . . . . . .  20
   Appendix A.  Example of Event . . . . . . . . . . . . . . . . . .  21
   Appendix B.  Changes between revisions  . . . . . . . . . . . . .  23
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23

1.  Introduction

   [RFC8328] defines a policy-based management framework that allow
   definition of a data model to be used to represent high-level,
   possibly network-wide policies.  This document defines an policy
   based Event Management YANG data model [RFC7950].  The policy based
   Event management YANG provides the ability for the network management
   function (within a controller, an orchestrator, or a network element)
   to monitor state changes on the network element and take simple and
   instant action when a trigger condition on the system state is met.

   The data model in this document is designed to be compliant with the
   Network Management Datastore Architecture (NMDA) [RFC8342].

2.  Conventions used in this document

2.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].  In this
   document, these words will appear with that interpretation only when



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   in ALL CAPS.  Lower case uses of these words are not to be
   interpreted as carrying [RFC2119] significance.

   This document uses the following terms:

   Error  A deviation of a system from normal operation [RFC3877].

   Fault  Lasting error or warning condition [RFC3877].

   Event  Something that happens which may be of interest or trigger the
      invocation of the rule.  A fault, an alarm, a change in network
      state, network security threat, hardware malfunction, buffer
      untilization crossing a threshold, network connection setup, an
      external input to the system, for example [RFC3877].

2.2.  Tree Diagrams

   Tree diagrams used in this document follow the notation defined in
   [RFC8340].

3.  Objectives

   This section describes some of the design objectives for the policy
   based Event management Data Model:

   o  The policy based Event management YANG should provide the ability
      for the network management function to control configuration and
      monitor state changes on a network element using the NETCONF/
      RESTCONF, and initiate simple actions whenever a trigger condition
      is met.  For example, a NETCONF subscribed notification can be
      generated when a system state value exceeds the threshold.

   o  Clear and precise identification of policy based Event types and
      managed objects.

   o  Allow the server to inform the client that certain Event are
      related to other Event.

   o  Allow one event to be able to trigger another external event or
      generate derived events.

   o  The event data model defined in this document can be implemented
      on the management system that also implements EVENT-MIB; thus, the
      mapping between the event data model and ENTITY-MIB should be
      clear.






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4.  Relationship to YANG Push

   YANG-push mechanism provides a subscription service for updates from
   a datastore.  And it supports two types of subscriptions which are
   distinguished by how updates are triggered: periodic and on-change.

   The On-change Push allow receivers to receive updates whenever
   changes to target managed objects occur.  This document specifies a
   mechanism that provides three trigger conditions:

   o  Existence: When a specific managed object appears, the trigger
      fires, e.g. reserved ports are configured.

   o  Boolean: The user can set the type of boolean comparison (e.g.
      unequal, equal, less, less-or-equal, greater, greater-or-equal,
      etc).  If the test result is true, the trigger fires.  The trigger
      will not fire again until the test result has become false and
      fall back to be true. e.g., when the boolean comparison type is
      'less', the trigger will be fired if the system state value of
      managed object is less than the value set for the target manged
      object.

   o  Threshold: The event that may be triggered when a managed object
      in multiple instances of the data tree is found and exceed the
      pre-configured threshold.  For example, when the system state
      value of that managed object is greater than or equal to 'rising-
      value' and the 'startup' is equal to 'rising', then one threshold
      rising event is triggered for that managed object.  Another
      example is if the system state value of the managed object is less
      than or equal to 'falling-value' and the 'startup' is equal to
      'falling' then one threshold falling event is triggered for that
      managed object.

   And the YANG Push mechanism more focus on the remote mirroring and
   monitoring of configuration and operational state.  For example, for
   on change method, the subscriber will receive a notification if the
   changes occurs.  The model defined in this document provides a method
   which allow automatic adjusting the value of the corresponding
   managed object when some event is triggered.  It establishes
   connection between network service monitoring and network service
   provision and can use output generated by network service monitoring
   as input of network service provision and thereby provide automated
   network management.  The details of the usage example is described in
   Appendix A.







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5.  Relationship to EVENT MIB

   If the device implements the EVENT-MIB [RFC2981], each entry in the
   "/events/event/trigger" list is mapped to MteTriggerEntry,MteTriggerE
   xistenceEntry,MteTriggerBooleanEntry,MteTriggerThresholdEntry,MteObje
   ctsEntry,MteEventEntry,MteEventSetEntry.  respectively.

   The following table lists the YANG data nodes with corresponding
   objects in the EVENT-MIB [RFC2981].










































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    +------------------------------|---------------------------------+
    |                              |                                 |
    | YANG data node in            |  EVENT-MIB Objects              |
    | ietf-event.yang              |  (RFC2981)                      |
    |                              |                                 |
    +----------------------------------------------------------------+
    |                              |                                 |
    | min-data-object              | mteResourceSampleMinimum        |
    |                              |                                 |
    | max-data-object              | mteResourceSampleInstanceMaximum|
    |                              |                                 |
    | traget                       | mteObjectsName                  |
    |                              |                                 |
    | event-name                   | mteEventName                    |
    |                              |                                 |
    | event-description            | mteEventComment                 |
    |                              |                                 |
    | value                        | mteEventSetValue                |
    |                              |                                 |
    | events/event/trigger/name    | mteTriggerName                  |
    |                              |                                 |
    | trigger-description          | mteTriggerComment               |
    |                              |                                 |
    | frequency                    | mteTriggerFrequency             |
    |                              |                                 |
    | comparison                   | mteTriggerBooleanComparison     |
    |                              |                                 |
    | value                        | mteTriggerBooleanValue          |
    |                              |                                 |
    | rising-event                 | mteTriggerThresholdRising       |
    |                              |                                 |
    | falling-event                | mteTriggerThresholdFalling      |
    |                              |                                 |
    | delta-rising-event           | mteTriggerThresholdDeltaRising  |
    |                              |                                 |
    | threshold/startup            | mteTriggerThresholdStartup      |
    |                              |                                 |
    | existence/enable             | mteTriggerExistenceStartup      |
    |                              |                                 |
    | boolean/enable               | mteTriggerBooleanStartup        |
    |                              |                                 |
    -------------------------------|---------------------------------|

6.  Model Overview

   The YANG data model for the Event management has been split into two
   modules:




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   o  The ietf-event-trigger.yang module defines a grouping for a
      generic trigger.  It is intended that this grouping will be used
      by the policy based event management model or other models that
      require the trigger conditions.  In this model, three trigger
      conditions are defined under the "test" choice node:

      *  Existence: When a specific managed object appears, the trigger
         fires.

      *  Boolean: If the test result on specific managed object is true
         the trigger fires.  The Boolean trigger condition is used when
         threshold value is a static value or pre-configured value.

      *  Threshold: The event that may be triggered when the system
         state value of a managed object within data-instance list
         exceed the threshold.  The threshold trigger condition is used
         when threshold value changes over time or the system state
         value of managed object changes in ascend or descend order.

   o  The ietf-event.yang module defines four lists: trigger, target,
      event, and action.  Triggers define the targets meeting some
      conditions that lead to events.  Events trigger corresponding
      actions:

      *  Each trigger can be seen as a logical test that, if satisfied
         or evaluated to be true, cause the action to be carried out.
         The ietf-event.yang module uses groupings defined in ietf-
         event-trigger.yang to present the trigger attributes.

      *  The target list defines managed objects that can be added to
         notifications or be set to a new value on the trigger, the
         trigger test type, or the event that resulted in the actions.

      *  The event list defines what happens when an event is triggered,
         i.e., trigger corresponding action, e.g., sending a
         notification, setting a value to the managed object or both.

      *  The action list consists of updates or invocations on local
         managed object attributes and defines a set of actions which
         will be performed (e.g. notification, set, another event, etc)
         when corresponding event be triggered.  The value to be set can
         use many variations on rule structure.

   The following tree diagrams [RFC8340] provide an overview of the data
   model for "ietf-event-trigger" module and the "ietf-event" module.

     groupings:
     trigger-grouping



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         +---- (test)?
            +--:(existences)
            |  +---- existences
            |     +---- target*       target
            +--:(boolean)
            |  +---- boolean
            |     +---- comparison?   enumeration
            |     +---- value?        match-value
            |     +---- target*       target
            +--:(threshold)
               +---- threshold
                  +---- rising-value?           match-value
                  +---- rising-target*          target
                  +---- falling-value?          match-value
                  +---- falling-target*         target
                  +---- delta-rising-value?     match-value
                  +---- delta-rising-target*    target
                  +---- delta-falling-value?    match-value
                  +---- delta-falling-target*   target
                  +---- startup?                enumeration


   module: ietf-event
       +--rw events
          +--rw min-data-object?            uint32
          +--rw max-data-object?   uint32
          +--rw event* [event-name type]
             +--rw event-name           string
             +--rw type                 identityref
             +--rw event-description?   string
             +--rw target*              trig:target
             +--rw clear?               boolean
             +--rw related-event* [event-name type]
             |  +--rw event-name    string
             |  +--rw type          identityref
             +--rw trigger* [name]
             |  +--rw name                   string
             |  +--rw type?                  enumeration
             |  +--rw trigger-description?   string
             |  +--rw frequency
             |  |  +--rw type?         identityref
             |  |  +--rw periodic
             |  |  |  +--rw interval    uint32
             |  |  |  +--rw start?      yang:date-and-time
             |  |  |  +--rw end?        yang:date-and-time
             |  |  +--rw scheduling
             |  |     +--rw month*          string
             |  |     +--rw day-of-month*   uint8



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             |  |     +--rw day-of-week*    uint8
             |  |     +--rw hour*           uint8
             |  |     +--rw minute*         uint8
             |  |     +--rw second*         uint8
             |  |     +--rw start?          yang:date-and-time
             |  |     +--rw end?            yang:date-and-time
             |  +--rw (test)?
             |     +--:(existences)
             |     |  +--rw existences
             |     |     +--rw target*   -> /events/event/target
             |     +--:(boolean)
             |     |  +--rw boolean
             |     |     +--rw comparison?   enumeration
             |     |     +--rw value?        match-value
             |     |     +--rw target*       target
             |     +--:(threshold)
             |        +--rw threshold
             |           +--rw rising-value?           match-value
             |           +--rw rising-target*          target
             |           +--rw falling-value?          match-value
             |           +--rw falling-target*         target
             |           +--rw delta-rising-value?     match-value
             |           +--rw delta-rising-target*    target
             |           +--rw delta-falling-value?    match-value
             |           +--rw delta-falling-target*   target
             |           +--rw startup?                enumeration
             +--rw action* [action-name]
                +--rw action-name           string
                +---n event-notification
                |  +---- event-name?   -> /events/event/event-name
                |  +---- type?         -> /events/event/type
                |  +---- target*       trig:target
                +---x set
                |  +---w input
                |     +---w target*   trig:target
                |     +---w value?    <anydata>
                +--rw trigger-event*        -> ../../event-name

   The relation between Event, Trigger, Target and Action is described
   as follows:











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   +-------------------------------+
   | Event                         |
   |  +-------+                    |
   |  |Target |                    |
   |  +---|---+                    |   +-------------------------------+
   |      |                        |   | Event                         |
   | +----V---+        +--------+  |   |  +-------+                    |
   | |Trigger |------->| Action |-------->|Target |                    |
   | +--------+        +--------+  |   |  +---|---+                    |
   +-------------------------------+   |      |                        |
                                       | +----|---+        +--------+  |
                                       | |Trigger |------- | Action |  |
                                       | +--------+        +--------+  |
                                       +-------------------------------+

   One event may trigger another event,i.e., the action output in the
   first event can be input to target in the second event, but if it
   does not trigger another event, the relation between action and
   target should be ignored.

7.  EVENT TRIGGER YANG Module

<CODE BEGINS> file "ietf-event-trigger@2018-12-18.yang"
module ietf-event-trigger {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-event-trigger";
  prefix trig;

  import ietf-yang-types {
    prefix yang;
  }

  organization
    "IETF xxx Working Group";
  contact
    "Zitao Wang: wangzitao@huawei.com
     Qin Wu: bill.wu@huawei.com";
  description
    "This module defines a reusable grouping for event trigger.";

  revision 2018-12-18 {
    description
      "Initial revision.";
    reference "foo";
  }

  typedef match-value {
    type union {



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      type yang:xpath1.0;
      type yang:object-identifier;
      type string;
    }
    description
      "This type is used to match resources of type 'target'.
       Since the type 'target' is a union of different types,
       the 'match-value' type is also a union of corresponding
       types.";
  }

  typedef target {
    type union {
      type instance-identifier;
      type yang:object-identifier;
      type yang:uuid;
      type string;
    }
    description
      "If the target is modelled in YANG, this type will
       be an instance-identifier.
       If the target is an SNMP object, the type will be an
       object-identifier.
       If the target is anything else, for example a distinguished
       name or a CIM path, this type will be a string.
       If the target is identified by a UUID use the uuid
       type.
       If the server supports several models, the presedence should
       be in the order as given in the union definition.";
  }

  grouping trigger-grouping {
    description
      "A grouping that provides event trigger.";
    choice test {
      description
        "Choice test";
      container existences {
        leaf-list target {
          type target;
          description
            "List for target objects";
        }
        description
          "Container for existence";
      }
      container boolean {
         leaf comparison {



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          type enumeration {
            enum "unequal" {
              description
                "Indicates that the comparision type is unequal to.";
            }
            enum "equal" {
              description
                "Indicates that the comparision type is equal to.";
            }
            enum "less" {
              description
                "Indicates that the comparision type is less than.";
            }
            enum "less-or-equal" {
              description
                "Indicates that the comparision type is less than
                or equal to.";
            }
            enum "greater" {
              description
                "Indicates that the comparision type is greater than.";
            }
            enum "greater-or-equal" {
              description
                "Indicates that the comparision type is greater than
                 or equal to.";
            }
          }
          description
            "Comparison type.";
        }
        leaf value {
          type match-value;
          description
            "Compartion value which is static threshold value.";
        }
        leaf target {
          type target;
          description
            "List for target management objects.";
        }
        description
          "Container for boolean test.";
      }
      container threshold {
        leaf rising-value {
          type match-value;
          description



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            "Sets the rising threshold to the specified value,
             when the current sampled value is greater than or equal to
             this threshold, and the value at the last sampling interval
             was less than this threshold, the event is triggered. ";
        }
        leaf-list rising-target {
          type target;
          description
            "List for target objects.";
        }
        leaf falling-value {
          type match-value;
          description
            "Sets the falling threshold to the specified value.";
        }
        leaf-list falling-target {
          type target;
          description
            "List for target objects.";
        }
        leaf delta-rising-value {
          type match-value;
          description
            "Sets the delta rising threshold to the specified value.";
        }
        leaf-list delta-rising-target {
          type target;
          description
            "List for target objects.";
        }
        leaf delta-falling-value {
          type match-value;
          description
            "Sets the delta falling threshold to the specified value.";
        }
        leaf-list delta-falling-target {
          type target;
          description
            "List for target objects.";
        }
        leaf startup {
          type enumeration {
            enum "rising" {
              description
                "If the first sample after this
                 managed object becomes active is greater than or equal
                  to 'rising-value' and the 'startup' is equal to
                  'rising' then one threshold rising event is



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                 triggered for that managed object.";
            }
            enum "falling" {
              description
                "If the first sample after this managed object becomes
               active is less than or equal to 'falling-value' and
               the 'startup' is equal to 'falling' then one
               threshold falling event is triggered for that managed
               object.";
            }
            enum "rising-or-falling" {
              description
                "That event may be triggered when the
                 'startup' is equal to 'rising-or-falling'.
                 'rising-or-falling' indicate the state value of the
                  managed object may less than or greater than the
                 specified thrshold value.";
            }
          }
          description
            "Startup setting.";
        }
        description
          "Container for the threshold trigger condition.
           Note that the threshold here  may change over time
           or the state value changes in either ascend order
           or descend order.";
      }
    }
  }
}

<CODE ENDS>

8.  EVENT YANG Module

   <CODE BEGINS> file "ietf-event@2018-09-18.yang"

module ietf-event {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-event";
  prefix evt;

  import ietf-yang-types {
    prefix yang;
  }

  import ietf-event-trigger {



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    prefix trig;
  }

  organization
    "IETF xxx Working Group";
  contact
    "Zitao Wang: wangzitao@huawei.com
     Qin Wu: bill.wu@huawei.com";
  description
    "This module defines a model for the service topology.";

  revision 2018-12-18 {
    description
      "Initial revision.";
    reference "foo";
  }

  identity event-type {
    description
      "Base identity for event type";
  }

  identity frequency {
    description
      "Base identity for frequency";
  }

  identity periodic {
    base frequency;
    description
      "Identity for periodic trigger";
  }

  identity scheduling {
    base frequency;
    description
      "Identity for scheduling trigger";
  }

  typedef match-value {
    type union {
      type yang:xpath1.0;
      type yang:object-identifier;
      type string;
    }
    description
      "This type is used to match resources of type 'target'.
       Since the type 'target' is a union of different types,



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       the 'match-value' type is also a union of corresponding
       types.";
  }

  typedef target {
    type union {
      type instance-identifier;
      type yang:object-identifier;
      type yang:uuid;
      type string;
    }
    description
      "If the target is modelled in YANG, this type will
       be an instance-identifier.
       If the target is an SNMP object, the type will be an
       object-identifier.
       If the target is anything else, for example a distinguished
       name or a CIM path, this type will be a string.
       If the target is identified by a UUID use the uuid
       type.
       If the server supports several models, the presedence should
       be in the order as given in the union definition.";
  }

  grouping start-end-grouping {
    description
      "A grouping that provides start and end times for
       Event objects.";
    leaf start {
      type yang:date-and-time;
      description
        "The date and time when the Event object
         starts to create triggers.";
    }
    leaf end {
      type yang:date-and-time;
      description
        "The date and time when the Event object
         stops to create triggers.
         It is generally a good idea to always configure
         an end time and to refresh the end time as needed
         to ensure that agents that lose connectivity to
         their Controller do not continue executing Schedules
         forever.";
    }
  }

  container events {



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    leaf min-data-object {
      type uint32;
      description
        "Sets the minimum number for a set of data collected
         or selected during the service monitoring.";
    }
    leaf max-data-object {
      type uint32;
      description
        "Sets the maximum number for a set of data collected or selected
        during the service monitoring.";
    }
    list event {
      key "event-name type";
      leaf event-name {
        type string;
        description
          "Event name";
      }
      leaf type {
        type identityref {
          base event-type;
        }
        description
          "Type of event";
      }
      leaf event-description {
        type string;
        description
          "Event description";
      }
      leaf-list target {
        type target;
        description
          "targeted objects";
      }
      leaf clear {
        type boolean;
        default "false";
        description
          "A flag indicate whether the event be closed";
      }
      list related-event {
        key "event-name type";
        leaf event-name {
          type string;
          description
            "Event name";



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        }
        leaf type {
          type identityref {
            base event-type;
          }
          description
            "Type of event";
        }
        description
          "List for related events";
      }

    uses trig:trigger-grouping;

      list action {
        key "action-name";
        leaf action-name {
          type string;
          description
            "Action name";
        }
        notification event-notification {
          leaf event-name {
            type leafref {
              path "/events/event/event-name";
            }
            description
              "Report the event name";
          }
          leaf type {
            type leafref {
              path "/events/event/type";
            }
            description
              "Report the event type";
          }
          leaf-list target {
            type target;
            description
              "Report the target objects";
          }
          description
            "This notification is used to report that an operator
             acted upon an Event.";
        }
        action set {
          input {
            leaf-list target {



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              type target;
              description
                "Report the target objects";
            }
            anydata value {
              description
                "Inline set content.";
            }
          }
        }
        leaf-list trigger-event {
          type leafref {
            path "../../event-name";
          }
          description
            "This action trigger another event";
        }
        description
          "List for Actions";
      }
      description
        "List for Events";
    }
    description
      "YANG data module for defining event triggers and
       actions for network management purposes";
  }
}

   <CODE ENDS>

9.  Security Considerations

   The YANG modules defined in this document MAY be accessed via the
   RESTCONF protocol [RFC8040] or NETCONF protocol ([RFC6241]).  The
   lowest RESTCONF or NETCONF layer requires that the transport-layer
   protocol provides both data integrity and confidentiality, see
   Section 2 in [RFC8040] and [RFC6241].  The lowest NETCONF layer is
   the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH)[RFC6242] . The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC5246].

   The NETCONF access control model [RFC6536] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.




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   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

   o  /events/event/event-name

   o  /events/event/target

   o  /events/action/set/target

   o  /events/event/trigger/name

10.  IANA Considerations

   This document registers a URI in the IETF XML registry [RFC3688].
   Following the format in [RFC3688], the following registration is
   requested to be made:

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

   This document registers a YANG module in the YANG Module Names
   registry [RFC6020].

   ---------------------------------------------------------------------
      Name:         ietf-event
      Namespace:    urn:ietf:params:xml:ns:yang:ietf-event
      Prefix:       evt
      Reference:    RFC xxxx
   ---------------------------------------------------------------------

11.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", March 1997.

   [RFC2981]  Kavasseri, R., Ed., "Event MIB", RFC 2981,
              DOI 10.17487/RFC2981, October 2000,
              <https://www.rfc-editor.org/info/rfc2981>.





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

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

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

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

   [RFC6370]  Bocci, M., Swallow, G., and E. Gray, "MPLS Transport
              Profile (MPLS-TP) Identifiers", RFC 6370,
              DOI 10.17487/RFC6370, September 2011,
              <https://www.rfc-editor.org/info/rfc6370>.

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

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC7952]  Lhotka, L., "Defining and Using Metadata with YANG",
              RFC 7952, DOI 10.17487/RFC7952, August 2016,
              <https://www.rfc-editor.org/info/rfc7952>.

   [RFC8328]  Liu, W., Xie, C., Strassner, J., Karagiannis, G., Klyus,
              M., Bi, J., Cheng, Y., and D. Zhang, "Policy-Based
              Management Framework for the Simplified Use of Policy
              Abstractions (SUPA)", RFC 8328, DOI 10.17487/RFC8328,
              March 2018, <https://www.rfc-editor.org/info/rfc8328>.

Appendix A.  Example of Event

   For example, some service requires to monitoring the "in-errors"
   state of the interface, and if the value of "in-errors" exceeds the
   threshold, the event should reset the interface's enabled value to
   false:



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   <events>
    <event>
     <event-name>interface-state-exception</event-name>
     <type>interface-exception</type>
     <target>/if:interfaces/if:interface[if:name='eth1']</target>
     <target>/if:interfaces/if:interface[if:name='eth2']</target>
     <target>/if:interfaces/if:interface[if:name='eth3']</target>
     <trigger>
      <name>evaluate-in-errors</name>
      <trigger-description>evaluate the number of
       the packets that contained errors
       </trigger-description>
      <frequency>10m</frequency>
      <type>threshold</type>
      <test>
       <threshold>
        <startup>rising</startup>
        <rising-value>100</rising-value>
        <rising-target>/if:interfaces/if:interface[if:name='eth1']
          /if:statistic/if:in-errors</rising-target>
        <rising-target>/if:interfaces/if:interface[if:name='eth2']
          /if:statistic/if:in-errors</trising-arget>
       </threshold>
      </test>
     </trigger>
     <action>
      <name>interface-exception</name>
      <event-notification>
       <event-name>interface-state-exception</event-name>
       <type>interface-exception</type>
       <target>/if:interfaces/if:interface[if:name='eth1']</target>
      </event-notification>
      <set>
       <target>/if:interfaces/if:interface[if:name='eth1']</target>
       <interger-value>
        <interfaces>
         <interface>
          <name>eth1</name>
          <enable>false</enable>
         </interface>
        </interfaces>
       </interger-value>
      </set>
     <action>
    </event>
   </events>





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Appendix B.  Changes between revisions

   v00 - v01

   o  Separate ietf-event-trigger.yang from Event management modeland
      ietf-event.yang and make it reusable in other YANG models.

   o  Clarify the difference between boolean trigger condition and
      threshold trigger condition.

   o  Change evt-smp-min and evt-smp-max into min-data-object and max-
      data-object in the data model.

Authors' Addresses

   Michael Wang
   Huawei Technologies,Co.,Ltd
   101 Software Avenue, Yuhua District
   Nanjing  210012
   China

   Email: wangzitao@huawei.com


   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: bill.wu@huawei.com


   Chongfeng Xie
   China Telecom

   Email: xiechf@ctbri.com.cn














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