Network Working Group                                        S. Chisholm
Internet-Draft                                                 K. Curran
Expires: July 12, 2006                                            Nortel
                                                              H. Trevino
                                                                   Cisco
                                                         January 8, 2006


                      NETCONF Event Notifications
                 draft-ietf-netconf-notification-00.txt

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
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   This Internet-Draft will expire on July 12, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   This memo defines a framework for sending asynchronous messages, or
   event notifications in NETCONF.  It defines both the operations
   necessary to support this concept, and also discusses implications
   for the mapping to application protocols.





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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1   Definition of Terms  . . . . . . . . . . . . . . . . . . .  4
     1.2   Event Notifications in NETCONF . . . . . . . . . . . . . .  5
   2.  Event-Related Operations . . . . . . . . . . . . . . . . . . .  6
     2.1   Subscribing to receive Events  . . . . . . . . . . . . . .  6
       2.1.1   create-subscription  . . . . . . . . . . . . . . . . .  6
     2.2   Sending Event Notifications  . . . . . . . . . . . . . . .  7
       2.2.1   Events . . . . . . . . . . . . . . . . . . . . . . . .  7
     2.3   Changing the Subscription  . . . . . . . . . . . . . . . .  8
       2.3.1   modify-subscription  . . . . . . . . . . . . . . . . .  9
     2.4   Terminating the Subscription . . . . . . . . . . . . . . . 10
       2.4.1   cancel-subscription  . . . . . . . . . . . . . . . . . 10
   3.  Supporting Concepts  . . . . . . . . . . . . . . . . . . . . . 11
     3.1   Capabilities Exchange  . . . . . . . . . . . . . . . . . . 11
     3.2   Querying Subscription Properties . . . . . . . . . . . . . 11
     3.3   RPC One-way Messages . . . . . . . . . . . . . . . . . . . 14
     3.4   User-Specified Filters . . . . . . . . . . . . . . . . . . 14
       3.4.1   Named Profiles . . . . . . . . . . . . . . . . . . . . 15
       3.4.2   Filtering  . . . . . . . . . . . . . . . . . . . . . . 15
     3.5   Event Classes  . . . . . . . . . . . . . . . . . . . . . . 15
     3.6   Defining Event Notifications . . . . . . . . . . . . . . . 16
     3.7   Interleaving Messages  . . . . . . . . . . . . . . . . . . 16
   4.  XML Schema for Event Notifications . . . . . . . . . . . . . . 18
   5.  Mapping to Application Protocols . . . . . . . . . . . . . . . 23
     5.1   SSH  . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
     5.2   BEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
       5.2.1   One-way Messages in Beep . . . . . . . . . . . . . . . 24
     5.3   SOAP . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
       5.3.1   A NETCONF over Soap over HTTP Example  . . . . . . . . 25
   6.  Filtering examples . . . . . . . . . . . . . . . . . . . . . . 28
     6.1   Event Classes  . . . . . . . . . . . . . . . . . . . . . . 28
     6.2   Subtree Filtering  . . . . . . . . . . . . . . . . . . . . 28
     6.3   XPATH filters  . . . . . . . . . . . . . . . . . . . . . . 30
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 32
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 33
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 34
   10.   References . . . . . . . . . . . . . . . . . . . . . . . . . 34
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 35
   A.  Potential Event Content  . . . . . . . . . . . . . . . . . . . 36
     A.1   Event Identifier . . . . . . . . . . . . . . . . . . . . . 36
     A.2   Resource Instance  . . . . . . . . . . . . . . . . . . . . 36
     A.3   Event Time . . . . . . . . . . . . . . . . . . . . . . . . 36
     A.4   Perceived Severity . . . . . . . . . . . . . . . . . . . . 36
     A.5   Probable Cause . . . . . . . . . . . . . . . . . . . . . . 37
     A.6   Specific Problem . . . . . . . . . . . . . . . . . . . . . 37
     A.7   Trend Indication . . . . . . . . . . . . . . . . . . . . . 37



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     A.8   Additional Alarm Text  . . . . . . . . . . . . . . . . . . 37
     A.9   Threshold Identifier . . . . . . . . . . . . . . . . . . . 37
     A.10  Threshold Type . . . . . . . . . . . . . . . . . . . . . . 38
     A.11  Observed Value . . . . . . . . . . . . . . . . . . . . . . 38
     A.12  State Change Information . . . . . . . . . . . . . . . . . 38
   B.  Configuration Event Class Notifications  . . . . . . . . . . . 39
     B.1   Types of Configuration Events  . . . . . . . . . . . . . . 39
     B.2   Config Event Notification Structure  . . . . . . . . . . . 40
     B.3   Configuration Event Content  . . . . . . . . . . . . . . . 42
       B.3.1   Target Datastore . . . . . . . . . . . . . . . . . . . 42
       B.3.2   User Info  . . . . . . . . . . . . . . . . . . . . . . 42
       B.3.3   Data Source  . . . . . . . . . . . . . . . . . . . . . 42
       B.3.4   Operation  . . . . . . . . . . . . . . . . . . . . . . 42
       B.3.5   Context  . . . . . . . . . . . . . . . . . . . . . . . 42
       B.3.6   Entered Command  . . . . . . . . . . . . . . . . . . . 43
       B.3.7   New Config . . . . . . . . . . . . . . . . . . . . . . 43
       B.3.8   Old Config . . . . . . . . . . . . . . . . . . . . . . 43
       B.3.9   Non-netconf commands in configuration notifications  . 43
     B.4   Design Alternative . . . . . . . . . . . . . . . . . . . . 43
       B.4.1   Server Session Initiation  . . . . . . . . . . . . . . 43
       B.4.2   Establishment  . . . . . . . . . . . . . . . . . . . . 44
       B.4.3   Teardown . . . . . . . . . . . . . . . . . . . . . . . 44
       B.4.4   Suspend And Resume . . . . . . . . . . . . . . . . . . 45
       B.4.5   Lifecycle  . . . . . . . . . . . . . . . . . . . . . . 45
   C.  NETCONF Event Notifications and Syslog . . . . . . . . . . . . 46
     C.1   Leveraging Syslog Field Definitions  . . . . . . . . . . . 46
       C.1.1   Field Mapping  . . . . . . . . . . . . . . . . . . . . 47
       C.1.2   Severity Mapping . . . . . . . . . . . . . . . . . . . 48
     C.2   Syslog within NETCONF Events . . . . . . . . . . . . . . . 48
       C.2.1   Motivation . . . . . . . . . . . . . . . . . . . . . . 48
       C.2.2   Embedding syslog messages in a NETCONF Event . . . . . 48
       C.2.3   Supported Forwarding Options . . . . . . . . . . . . . 49
       Intellectual Property and Copyright Statements . . . . . . . . 51


















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1.  Introduction

   NETCONF [NETCONF-PROTO] can be conceptually partitioned into four
   layers:

                Layer                      Example
            +-------------+      +-----------------------------+
            |   Content   |      |     Configuration data      |
            +-------------+      +-----------------------------+
                   |                           |
            +-------------+      +-----------------------------+
            | Operations  |      | <get-config>, <edit-config> |
            +-------------+      +-----------------------------+
                   |                           |
            +-------------+      +-----------------------------+
            |     RPC     |      |    <rpc>, <rpc-reply>       |
            +-------------+      +-----------------------------+
                   |                           |
            +-------------+      +-----------------------------+
            | Application |      |   BEEP, SSH, SSL, console   |
            |   Protocol  |      |                             |
            +-------------+      +-----------------------------+

   This document defines a framework for sending asynchronous messages,
   or event notifications in NETCONF.  It defines both the operations
   necessary to support this concept, and also discusses implications
   for the mapping to application protocols.

                                 Figure 1


1.1  Definition of Terms

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [3].

   Element: An XML Element[XML].

   Managed Entity: A node, which supports NETCONF[NETCONF] and has
      access to management instrumentation.  This is also known as the
      NETCONF server.

   Managed Object: A collection of one of more Elements that define an
      abstract thing of interest.






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1.2  Event Notifications in NETCONF

   An event is something that happens which may be of interest - a
   configuration change, a fault, a change in status, crossing a
   threshold, or an external input to the system, for example.  Often
   this results in an asynchronous message, sometimes referred to as a
   notification or event notification, being sent out to interested
   parties to notify them that this event has occurred.

   This memo defines a mechanism whereby the NETCONF client indicates
   interest in receiving event notifications from a NETCONF server by
   creating a subscription to receive event notifications.  The NETCONF
   server replies to indicate whether the subscription request was
   successful and, if it was successful, begins sending the event
   notifications to the NETCONF client as the events occur within the
   system.  These event notifications will continue to be sent until
   either the NETCONF session is terminated or an explicit command to
   cancel the subscription is sent.  The event notification subscription
   allows a number of options to enable the NETCONF client to specify
   which events are of interest.  These are specified when the
   subscription is created, but can be modified later using a modify
   subscription command.





























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2.  Event-Related Operations

2.1  Subscribing to receive Events

   The event notification subscription is initiated by the NETCONF
   client and responded to by the NETCONF server.  When the event
   notification subscription is created, the events of interest are
   specified.

   It is possible to create more than one event notification
   subscription on a single underlying connection.  Each event
   notification subscription therefore has its own unique identifier.

   Content for an event notification subscription can be selected by
   specifying which event classes are of interest and /or by applying
   user-specified filters.

2.1.1  create-subscription

   <create-subscription>

   Description:

      This command initiates an event notification subscription which
      will send asynchronous event notifications to the initiator of the
      command until the  <cancel-subscription >  command is sent.

   Parameters:

      Event Classes:

         An optional parameter that indicates which event classes are of
         interest.  If not present, events of all classes will be sent.

      Filter:

         An optional parameter that indicates which subset of all
         possible events are of interest.  The format of this parameter
         is the same as that of the filter parameter in the NETCONF
         protocol operations.  If not present, all events not precluded
         by other parameters will be sent.  These filter parameters can
         only be modified using the modify-subscription command.

      Named Profile







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         An optional parameter that points to a separately defined
         filter profile.  If not present, no additional filtering will
         be applied.  If the separate definition of these filters is
         updated, then these changes will be reflected in the filtered
         events on this subscription.

   Positive Response:

      If the NETCONF server can satisfy the request, the server sends an
      <rpc-reply>  element containing a <data> element containing the
      subscription ID.

   Negative Response:

      An  <rpc-error> element is included within the <rpc-reply>  if the
      request cannot be completed for any reason.


2.2  Sending Event Notifications

   Once the subscription has been set up, the NETCONF server sends the
   event notifications asynchronously along the connection.
   Notifications are tagged with event classes, subscription ID,
   sequence number, and date and time.

2.2.1  Events

   Events

   <notification>

   Description:

      An event notification is sent to the initiator of an <create-
      subscription>  command asynchronously when an event of interest to
      them has occurred.  An event notification is a complete XML
      document.

   Parameters:

      Event Classes:

         The event class or classes associated with this event
         notification







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      Subscription Id:

         A unique identifier for this event subscription

      Sequence Number:

         A sequentially increasing number to uniquely identify event
         notifications for this subscription.  It starts at 0, always
         increases by just one and rolls back to 0 after its maximum
         value is reached.

      Date and Time:

         The date and time that the event notification was sent by the
         NETCONF server.

   Positive Response:

      No response.

   Negative Response:

      No response.


2.2.1.1  Event Notification

   The NETCONF Event notification structure is shown in the following
   figure.

   _____________
   |RPC-Header||
   |__________||
   |message-id||
   |__________||
   ____________________________________________________________________
   || Event Header                                             || Data |
   ||__________________________________________________________||______|
   || subscriptionId| eventClasses| sequenceNumber| dataAndTime||      |
   ||_______________|_____________|_______________|____________||______|


2.3  Changing the Subscription

   After an event notification subscription has been established, the
   NETCONF client can initiate a request to change properties of the
   event notification subscription.  This prevents loss of event
   notifications that might otherwise occur during a tear down and



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   recreation of the event notification subscription.  This command is
   responded to by the NETCONF server

2.3.1  modify-subscription

   <modify-subscription>

   Description:

      Change properties of the event notification subscription.

   Parameters:

      Subscription Id:

         A unique identifier for this event subscription.

      Event Classes:

         An optional parameter that indicates which Event Classes are of
         interest.  If not present, events of all classes will be sent.

      Filter:

         An optional parameter that indicates which subset of all
         possible events that are of interest.  The format is the same
         filter used for other NETCONF commands.  If not present,  all
         events not precluded by other parameters will be sent.  These
         filter parameters can only be modified using the modify-
         subscription command.

      Named Profile:

         An optional parameter that points to separately defined filter
         profile.  If not present, no additional filtering will be
         applied.  If the separate definition of these filters is
         updated, then these changes will be reflected in the events
         seen on this subscription.

   Positive Response:

      If the NETCONF server was able to satisfy the request, an <rpc-
      reply> is sent that includes an  <ok>  element.

   Negative Response:






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      An <rpc-error> element is included within the <rpc-reply> if the
      request cannot be completed for any reason.


2.4  Terminating the Subscription

   Closing of the event notification subscription is initiated by the
   NETCONF client.  The specific subscription to be closed is specified
   using a subscription ID.  The NETCONF server responds.  Note that the
   NETCONF session may also be torn down for other reasons and this will
   also result in the subscription being cancelled, but is not subjected
   to the behaviour of this command.

2.4.1  cancel-subscription

   <cancel-subscription>

   Description:

      Tear down the event notification subscription.

   Parameters:

      Subscription Id:

         A unique identifier for this event notification subscription.

   Positive Response:

      If the NETCONF server was able to satisfy the request, an <rpc-
      reply> is sent that includes an <ok> element.

   Negative Response:

      An <rpc-error> element is included within the <rpc-reply> if the
      request cannot be completed for any reason.















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3.  Supporting Concepts

3.1  Capabilities Exchange

   The ability to process and send event notifications is advertised
   during the capability exchange between the NETCONF client and server.

   "urn:ietf:params:xml:ns:netconf:notification:1.0"

   For Example


      <hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <capabilities>
          <capability>
            urn:ietf:params:xml:ns:netconf:base:1.0
          </capability>
          <capability>
            urn:ietf:params:xml:ns:netconf:capability:startup:1.0
          </capability>
          <capability>
            urn:ietf:params:xml:ns:netconf:notification:1.0
          </capability>
        </capabilities>
        <session-id>4</session-id>
      </hello>



3.2  Querying Subscription Properties

   The following Schema can be used to retrieve information about active
   event notification subscriptions


           <xs:schema
       xmlns:xs="http://www.w3.org/2001/XMLSchema"
       xmlns=
      "urn:ietf:params:xml:ns:netconf:subscription:1.0"
      targetNamespace=
      "urn:ietf:params:xml:ns:netconf:subscription:1.0"
      xmlns:netconf=
      "urn:ietf:params:xml:ns:netconf:base:1.0"
      xmlns:ncEvent=
      "urn:ietf:params:xml:ns:netconf:notification:1.0"
       elementFormDefault="qualified"
       attributeFormDefault="unqualified" xml:lang="en">
        <annotation>



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                       <documentation xml:lang="en">
                         Schema for reporting on Event Subscriptions
         </documentation>
         <appinfo>
           <nm:identity
               xmlns:nm="urn:ietf:params:xml:ns:netmod:base:1.0">
               <nm:Name>NetConf State Schema</nm:Name>
               <nm:LastUpdated>2005-11-30T09:30:47-05:00
               </nm:LastUpdated>
               <nm:Organization>IETF</nm:Organization>
               <nm:Description>
                  A schema that can be used to learn about current
                  NetConf Event Subscriptions
               </nm:Description>
             </nm:identity>
           </appinfo>
              </annotation>

       <xs:import namespace="http://www.w3.org/XML/1998/namespace"
                  schemaLocation="http://www.w3.org/2001/xml.xsd"/>
       <xs:import
            namespace="urn:ietf:params:xml:ns:netconf:notification:1.0"
                        schemaLocation="ietf-netconf-notification.xsd"/>
       <xs:import namespace="urn:ietf:params:xml:ns:netconf:base:1.0"
                   schemaLocation="draft-ietf-netconf-prot-09.xsd"/>


      <xs:element name="netconfSubscription">
        <xs:complexType>
        <xs:sequence maxOccurs="unbounded">

          <xs:element name="session-id"
                            type="netconf:SessionId" >
            <xs:annotation>
              <xs:documentation xml:lang="en">
              The session id associated with this subscription.
              </xs:documentation>
           </xs:annotation>
          </xs:element>

                 <xs:element name="subscriptionID"
                            type="ncEvent:SubscriptionID" >
            <xs:annotation>
              <xs:documentation xml:lang="en">
              The subscription id associated with this subscription.
              </xs:documentation>
           </xs:annotation>
          </xs:element>



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          <xs:element name="eventClasses">
            <xs:annotation>
              <xs:documentation xml:lang="en">
              The event classes associated with this subscription.
              </xs:documentation>
           </xs:annotation>
           <xs:complexType>
             <xs:sequence minOccurs="0" maxOccurs="unbounded">
               <xs:element ref="ncEvent:EventClass"/>
             </xs:sequence>
           </xs:complexType>
          </xs:element>

            <xs:element name="filter"
                        type="netconf:filterInlineType"  minOccurs="0">
            <xs:annotation>
              <xs:documentation xml:lang="en">
              The filters associated with this subscription.
              </xs:documentation>
           </xs:annotation>
          </xs:element>

          <xs:element name="namedProfile"
                type="xs:string" minOccurs="0">
                         <xs:annotation>
              <xs:documentation xml:lang="en">
              The named profile associated with this subscription.
              Note that the contents of the named profile may have
              changed since it was last applied
              </xs:documentation>
           </xs:annotation>
           </xs:element>

          <xs:element name="lastModified"
                type="xs:dateTime" >
                         <xs:annotation>
              <xs:documentation xml:lang="en">
              The last time this subscription was modified. If it has
              not been modified since creation, this is the time of
              subscription creation.
              </xs:documentation>
           </xs:annotation>
           </xs:element>

           <xs:element name="messagesSent"
                type="xs:integer" minOccurs="0">
                         <xs:annotation>
              <xs:documentation xml:lang="en">



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              A count of event notifications sent along this connection
              since the subscription was created.
              </xs:documentation>
           </xs:annotation>
           </xs:element>

           <xs:element name="lastSequenceNumber"
                type="xs:integer" minOccurs="0">
                         <xs:annotation>
              <xs:documentation xml:lang="en">
              The sequence number of the last event notification sent to
              this subscription
              </xs:documentation>
           </xs:annotation>
           </xs:element>

           <xs:key name="uniqueSubscription">
             <xs:selector xpath=".//subscription"/>
             <xs:field xpath="session-id"/>
             <xs:field xpath="subscriptionID"/>
             </xs:key>

         </xs:sequence>
         </xs:complexType>
         </xs:element>

       </xs:schema>



3.3  RPC One-way Messages

   In order to support the concept that each individual event
   notification is a well-defined XML-document that can be processed
   without waiting for all events to come in, it makes sense to define
   events, not as an endless reply to a subscription command, but as
   independent messages that originate from the NETCONF server.  In
   order to support this model, this memo introduces the concept of a
   one-way RPC message.

   The one-way RPC message is similar to the two-way RPC message, except
   that no response is expected to the command.  In the case of event
   notification, this RPC will originate from the NETCONF server, and
   not the NETCONF client.

3.4  User-Specified Filters

   Note that when multiple filters are specified, they are applied



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   collectively, so event notifications needs to pass all specified
   filters in order to be sent to the subscriber.  If a filter is
   specified to look for data of a particular value, and the data item
   is not present within a particular event for its value to be checked,
   it will be filtered out.  For example, if one were to check for
   'severity=critical' in a configuration event notification where this
   field was not supported, then the notification would be filtered out.

3.4.1  Named Profiles

   A named profile is a filter that is created ahead of time and applied
   at the time an event notification subscription is created or
   modified.  Note that changes to the profile after the subscription
   has been created will have no effect unless a modify subscription
   command is issued.  Since named profiles exist outside of the
   subscription, they persist after the subscription has been cancelled.

3.4.2  Filtering

   Just-in-time filtering is explicitly stated when the event
   notification subscription is created.  It can only be changed using
   the modify subscription command.  This is specified via the Filter
   parameter.  Filters only exist as parameters to the subscription.

3.5  Event Classes

   Events can be broadly classified into one more event classes.  Each
   event class identifies a set of event notifications which share
   important characteristics, such being generated from similar events
   or sharing much of the same content.

   The initial set of event classes is fault, configuration, state,
   audit, data, maintenance, metrics, security, information and
   heartbeat.

   A fault event notification is generated when a fault condition (error
   or warning) occurs.  A fault event may result in an alarm.  Examples
   of fault events could be a communications alarm, environmental alarm,
   equipment alarm, processing error alarm, quality of service alarm, or
   a threshold crossing event.  See RFC3877 and RFC2819 for more
   information.

   A configuration event, alternatively known as an inventory event, is
   used to notify that hardware, software, or a service has been added/
   changed/removed.  In keeping aligned with NETCONF protocol
   operations,  configuration events may included copy configuration
   event, delete configuration event, or the edit configuration event
   (create, delete, merge, replace).



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   A state event indicates a change from one state to another, where a
   state is a condition or stage in the existence of a managed entity.
   State change events are seen in many specifications.  For Entity
   state changes, see [Entity-State-MIB] for more information.

   Audit events provide event of very specific actions within a managed
   device.  In isolation an audit events provides very limited data.  A
   collection of audit information forms an audit trail.

   A data dump event is an asynchronous event containing information
   about a system, its configuration, state, etc.

   A maintenance event signals the beginning, process or end of an
   action either generated by a manual or automated  maintenance action.

   A metrics event contains a metric or a collection of metrics.  This
   includes performance metrics.

   A heart beat event is sent periodically to enable testing that the
   communications channel is still functional.  It behaves much like the
   other event classes, with the exception that implementations may not
   want to include an event log, if supported.  Although widely used
   throughout the industry, no current corresponding work within the
   IETF.  However, other standards bodies such as the TeleManagement
   Forum have similar definitions.

   An Information event is something that happens of interest which is
   within the expected operational behaviour and not otherwise covered
   by another class.

3.6  Defining Event Notifications

   Event Notifications are defined ahead of time by defining an XML
   element and assigning it to particular event classes.  This will be
   done using an "eventClasses" attribute.

3.7  Interleaving Messages

   While each NETCONF message must be a complete XML document, the
   design of the event system allows for the interleaving of complete
   asynchronous event notifications with complete synchronous messages.
   It is possible to still send command-response type messages such as
   <modify-subscription> while events are being generated.  The only
   restriction is that each message must be complete







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   The following sequence diagram demonstrates an example NETCONF
   session where after basic session establishment and capability
   exchange, NETCONF client (C), subscribes to receive event
   notifications.  The NETCONF server (S), starts sending event
   notifications as events of interest happen within the system.  The
   NETCONF client decides to change the characteristics of their event
   subscription so sends a  <modify-subscription> command.  Before the
   NETCONF server, receives this command, another event is generated and
   the NETCONF server starts to send the event notification.  The
   NETCONF server finishes sending this event notification before
   processing the  <modify-subscription> command and sending the reply.


                             C                           S
                             |                           |
                             |  capability exchange      |
                             |-------------------------->|
                             |<------------------------->|
                             |                           |
                             |  <create-subscription>    |
                             |-------------------------->|
                             |<--------------------------|
                             |                           |
                             |     <notification>        |
                             |<--------------------------|
                             |                           |
                             |     <notification>        |
                             |<--------------------------|
                             |                           |
                             |  <modify-subscription>    |
                             |-------------------------->| (buffered)
                             |     <notification>        |
                             |<--------------------------|
                             |  <rpc-reply>              |
                             |<--------------------------|
















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4.  XML Schema for Event Notifications


   <?xml version="1.0" encoding="UTF-8"?>
      <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
             xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"
             xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0"
       targetNamespace="urn:ietf:params:xml:ns:netconf:notification:1.0"
             elementFormDefault="qualified"
             attributeFormDefault="unqualified"
               xml:lang="en">
        <!--
          import standard XML definitions
          -->
        <xs:import namespace="http://www.w3.org/XML/1998/namespace"
                   schemaLocation="http://www.w3.org/2001/xml.xsd">
          <xs:annotation>
            <xs:documentation>
              This import accesses the xml: attribute groups for the
              xml:lang as declared on the error-message element.
            </xs:documentation>
          </xs:annotation>
        </xs:import>

        <!-- import base netconf definitions -->
    <xs:import namespace="urn:ietf:params:xml:ns:netconf:base:1.0"
          schemaLocation="urn:ietf:params:xml:ns:netconf:base:1.0" />


   <!-- ************** Type definitions ***********************-->

        <xs:simpleType name="SubscriptionID">
        <xs:annotation>
          <xs:documentation>
          The unique identifier for this particular subscription within
          the session.
          </xs:documentation>
          </xs:annotation>
           <xs:restriction base="xs:string"/>
           </xs:simpleType>

           <xs:simpleType name="SequenceNumber">
        <xs:annotation>
          <xs:documentation>
          A monotonically  increasing integer. Starts at 0.
          Always increases by just one. Roll back to 0 after maximum
          value is reached.
          </xs:documentation>



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          </xs:annotation>
           <xs:restriction base="xs:integer"/>
           </xs:simpleType>

           <xs:complexType name="EventClassType"/>
           <xs:element name="EventClass"
                       type="EventClassType" abstract="true"/>
           <xs:element name="fault" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="information" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="state" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="configuration" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="data" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="maintenance" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="metrics" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="security" type="EventClassType"
                       substitutionGroup="EventClass"/>
           <xs:element name="heartbeat" type="EventClassType"
                       substitutionGroup="EventClass"/>

         <xs:complexType name="EventClasses">
           <xs:sequence maxOccurs="unbounded">
             <xs:element ref="EventClasses" />
           </xs:sequence>
         </xs:complexType>



   <!-- ************** Symmetrical Operations  ********************-->


        <!--
          <create-subscription> operation
          -->
        <xs:complexType name="createSubscriptionType">
          <xs:complexContent>
            <xs:extension base="netconf:rpcOperationType">
              <xs:sequence>
                <xs:element name="event-classes"
                                     minOccurs="0">
                  <xs:complexType>
                     <xs:complexContent>



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                       <xs:extension base="EventClasses"/>
                     </xs:complexContent>
                   </xs:complexType>
                 </xs:element>
                <xs:element name="filter"
                     type="netconf:filterInlineType" minOccurs="0"/>
                <xs:element name="named-profile"
                            type="xs:string" minOccurs="0"/>
              </xs:sequence>
            </xs:extension>
          </xs:complexContent>
        </xs:complexType>
        <xs:element name="create-subscription"
                    type="createSubscriptionType"
                    substitutionGroup="netconf:rpcOperation"/>

        <!--
          <modify-subscription> operation
          -->
        <xs:complexType name="modifySubscriptionType">
          <xs:complexContent>
            <xs:extension base="netconf:rpcOperationType">
              <xs:sequence>
                <xs:element name="subscription-id"
                                 type="SubscriptionID" />
                <xs:element name="event-classes"
                                      minOccurs="0">
                  <xs:complexType>
                     <xs:complexContent>
                       <xs:extension base="EventClasses"/>
                     </xs:complexContent>
                   </xs:complexType>
                 </xs:element>
                <xs:element name="filter"
                            type="netconf:filterInlineType"
                            minOccurs="0"/>
                <xs:element name="named-profile"
                            type="xs:string" minOccurs="0"/>
              </xs:sequence>
            </xs:extension>
          </xs:complexContent>
        </xs:complexType>
        <xs:element name="modify-subscription"
                    type="modifySubscriptionType"
                    substitutionGroup="netconf:rpcOperation"/>

        <!--
          <cancel-subscription> operation



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          -->
        <xs:complexType name="cancelSubscriptionType">
          <xs:complexContent>
            <xs:extension base="netconf:rpcOperationType">
              <xs:sequence>
                <xs:element name="subscription-id"
                     type="SubscriptionID" />
              </xs:sequence>
            </xs:extension>
          </xs:complexContent>
        </xs:complexType>
        <xs:element name="cancel-subscription"
                    type="cancelSubscriptionType"
                    substitutionGroup="netconf:rpcOperation"/>


   <!-- ************** One-way Operations  ******************-->

        <xs:complexType name="rpcOneWayType">
            <xs:group ref="rpc-one-way"/>
          <xs:attribute name="message-id" type="xs:string"
                       use="optional"/>
        </xs:complexType>
        <xs:group name="rpc-one-way">
          <xs:sequence>
            <xs:element name="data" type="netconf:dataInlineType"
                            minOccurs="0"/>
          </xs:sequence>
        </xs:group>

          <!--
          <Event> operation
          -->
        <xs:complexType name="NotificationType">
          <xs:complexContent>
            <xs:extension base="rpcOneWayType">
              <xs:sequence>
                <xs:element name="subscription-id"
                                     type="SubscriptionID"/>
                <xs:element name="event-classes" type="EventClasses"/>
                <xs:element name="sequence-number"
                                  type="SequenceNumber"/>
                <xs:element name="date-time" type="xs:dateTime">
                   <xs:annotation>
                      <xs:documentation>
                      The date and time that the event notification was
                      sent by the netconf server.
                      </xs:documentation>



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                   </xs:annotation>
                </xs:element>
              </xs:sequence>
            </xs:extension>
          </xs:complexContent>
        </xs:complexType>
        <xs:element name="notification" type="NotificationType"/>

      </xs:schema>










































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5.  Mapping to Application Protocols

   Currently, the NETCONF family of specification allows for running
   NETCONF over a number of application protocols, some of which support
   multiple configurations.  Some of these options will be better suited
   for supporting event notifications then others.

5.1  SSH

   Session establishment and two-way messages are based on the NETCONF
   over SSH transport mapping [NETCONF-SSH]

   One-way messages are supported as follows: Once the session has been
   established and capabilities have been exchanged, the server may send
   complete XML documents to the NETCONF client containing rpc-one-way
   elements.  No response is expected from the NETCONF client.

   As the other examples in [NETCONF-SSH] illustrate, a special
   character sequence, MUST be sent by both the client and the server
   after each XML document in the NETCONF exchange.  This character
   sequence cannot legally appear in an XML document, so it can be
   unambiguously used to identify the end of the current document in the
   event notification of an XML syntax or parsing error, allowing
   resynchronization of the NETCONF exchange.

   The NETCONF over SSH session to receive an event notification might
   look like this:
























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       <?xml version="1.0" encoding="UTF-8"?>
       <rpc-one-way message-id="105"
                xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
          <notification>
            <subscription-id>123456</subscription-id>
            <event-class><configuration/><audit/></event-classes>
            <sequence-number>2</sequence-number>
            <date-time>2000-01-12T12:13:14Z</date-time>
              <data>
                 <user>Fred Flinstone</user>
                 <operation>
                  <edit-config>
                    <target>
                     <running/>
                    </target>
                    <config>
                      <top xmlns="http://example.com/schema/1.2/config">
                         <interface>
                           <name>Ethernet0/0</name>
                           <mtu>1500</mtu>
                        </interface>
                      </top>
                   </config>
                 </edit-config>
               </operation>
             </data>
          </notification>
        </rpc-one-way>
        ]]>
    ]]>


5.2  BEEP

   Session establishment and two-way messages are based on the NETCONF
   over BEEP transport mapping NETCONF-BEEP

5.2.1  One-way Messages in Beep

   One-way messages can be supported either by mapping to the existing
   one-to-many BEEP construct or by creating a new one-to-none
   construct.

   This area is for future study.

5.2.1.1  One-way messages via the One-to-many Construct

   Messages in one-to-many exchanges: "rcp", "rpc-one-way", "rpc-reply"



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   Messages in positive replies: "rpc-reply", "rpc-one-way"

5.2.1.2  One-way messages via the One-to-none Construct

   Note that this construct would need to be added to an extension or
   update to 'The Blocks Extensible Exchange Protocol Core' RFC 3080.

   MSG/NoANS: the client sends a "MSG" message, the server, sends no
   reply.

   In one-to-none exchanges, no reply to the "MSG" message is expected.

5.3  SOAP

   Session management and message exchange are based on the NETCONF over
   SOAP transport mapping NETCONF-SOAP

   Note that the use of "persistent connections" "chunked transfer-
   coding" when using HTTP becomes even more important in the supporting
   of event notifications

5.3.1  A NETCONF over Soap over HTTP Example

      C: POST /netconf HTTP/1.1
      C: Host: netconfdevice
      C: Content-Type: text/xml; charset=utf-8
      C: Accept: application/soap+xml, text/*
      C: Cache-Control: no-cache
      C: Pragma: no-cache
      C: Content-Length: 465
      C:
      C: <?xml version="1.0" encoding="UTF-8"?>
      C: <soapenv:Envelope
      C:   xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
      C:   <soapenv:Body>
      C:     <rpc message-id="101"
      C:        xmlns=
              "xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
      C:       <create-subscription>
      C:       </create-subscription>
      C:     </rpc>
      C:   </soapenv:Body>
      C: </soapenv:Envelope>

      The response:

      S: HTTP/1.1 200 OK
      S: Content-Type: application/soap+xml; charset=utf-8



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      S: Content-Length: 917
      S:
      S: <?xml version="1.0" encoding="UTF-8"?>
      S: <soapenv:Envelope
      S:   xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
      S:   <soapenv:Body>
      S:     <rpc-reply message-id="101"
      S:        xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
      S:       <data>
      S:         <top xmlns=
                      "http://example.com/schema/1.2/notification">
      S:           <subscriptionId>123456</subscriptionId>
      S:         </top>
      S:       </data>
      S:     </rpc-reply>
      S:   </soapenv:Body>
      S: </soapenv:Envelope>

      And then some time later

      S: HTTP/1.1 200 OK
      S: Content-Type: application/soap+xml; charset=utf-8
      S: Content-Length: 917
      S:
      S: <?xml version="1.0" encoding="UTF-8"?>
      S: <soapenv:Envelope
      S:   xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
      S:   <soapenv:Body>
      S:     <rpc-one-way message-id="101"
      S:        xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
      S:       <data>
      S:     <notification>
      S:      <subscriptionID>123456</subscriptionID>
      S:      <eventClass><configuration/><audit/></eventClass>
      S:      <sequenceNumber>2</sequenceNumber>
      S:           <dateAndTime>2000-01-12T12:13:14Z</dateAndTime>
      S:        <data>
      S:           <user>Fred Flinstone</user>
      S:              <operation>
      S:               <edit-config>
      S:              <target>
      S:               <running/>
      S:              </target>
      S:             <config>
      S:              <top xmlns="http://example.com/schema/1.2/config">
      S:                   <interface>
      S:                     <name>Ethernet0/0</name>
      S:                     <mtu>1500</mtu>



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      S:                  </interface>
      S:               </top>
      S:            </config>
      S:           </edit-config>
      S:         </operation>
      S:       </data>
      S:    </notification>
      S:       </data>
      S:     </rpc-one-way>
      S:   </soapenv:Body>
      S: </soapenv:Envelope>








































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6.  Filtering examples

   The following section provides examples to illustrate the various
   methods of filtering content on an event notification subscription.

6.1  Event Classes

   The following example illustrates selecting all event notifications
   for EventClasses fault, state or config

        <rpc message-id="101"
             xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
          <create-subscription>
            <eventClasses>
               <fault/>
               <state/>
               <config/>
            </eventClasses>
          </create-subscription>
        </rpc>


6.2  Subtree Filtering

   XML subtree filtering is not well suited for creating elaborate
   filter definitions given that it only supports equality comparisons
   (e.g. in the event subtree give me all event notifications which have
   severity=critical or severity=major or severity=minor).
   Nevertheless, it may be used for defining simple notification
   forwarding filters as shown below.

   The following example illustrates selecting fault EventClass which
   have severities of critical, major, or minor.  The filtering criteria
   evaluation is as follows:

   ((fault) & ((severity=critical) | (severity=major) | (severity =
   minor)))














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        <rpc message-id="101"
             xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
          <create-subscription>
            <eventClasses>
               <fault/>
            </eventClasses>
            <netconf:filter type="subtree">
              <neb xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
                <event>
                    <severity>critical</severity>
                </event>
                <event>
                    <severity>major</severity>
                </event>
                <event>
                    <severity>minor</severity>
                </event>
              </neb>
            </netconf:filter>
          </create-subscription>
        </rpc>

   The following example illustrates selecting fault, state, config
   EventClasses which have severities of critical, major, or minor and
   come from card Ethernet0.  The filtering criteria evaluation is as
   follows:

   ((fault | state | config) & ((fault & severity=critical) | (fault &
   severity=major) | (fault & severity = minor) | (card=Ethernet0)))






















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        <rpc message-id="101"
             xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
          <create-subscription>
            <eventClasses>
               <fault/>
               <state/>
               <config/>
            </eventClasses>
            <netconf:filter type="subtree">
              <neb xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
                <event>
                    <eventClasses>fault</eventClasses>
                    <severity>critical</severity>
                </event>
                <event>
                    <eventClasses>fault</eventClasses>
                    <severity>major</severity>
                </event>
                <event>
                    <eventClasses>fault</eventClasses>
                    <severity>minor</severity>
                </event>
                <event>
                    <card>Ethernet0</card>
                </event>
              </neb>
            </netconf:filter>
          </create-subscription>
        </rpc>



6.3  XPATH filters

   The following example illustrates selecting fault EventClass which
   have severities of critical, major, or minor.  The filtering criteria
   evaluation is as follows:

   ((fault) & ((severity=critical) | (severity=major) | (severity =
   minor)))











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        <rpc message-id="101"
             xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
          <create-subscription>
            <eventClasses>
               <fault/>
            </eventClasses>
            <netconf:filter type="xpath">
              (/event[eventClasses/fault] and
              (/event[severity="critical"] or
               /event[severity="major"] or /event[severity="minor"]))
            </netconf:filter>
          </create-subscription>
        </rpc>


   The following example illustrates selecting fault, state, config
   EventClasses which have severities of critical, major, or minor and
   come from card Ethernet0.  The filtering criteria evaluation is as
   follows:

   ((fault | state | config) & ((fault & severity=critical) | (fault &
   severity=major) | (fault & severity = minor) | (card=Ethernet0)))


        <rpc message-id="101"
             xmlns="urn:ietf:params:xml:ns:netconf:event:1.0">
          <create-subscription>
            <eventClasses>
               <fault/>
               <state/>
               <config/>
            </eventClasses>
            <netconf:filter type="xpath">
               ((/event[eventClasses/fault]  or
               /event[eventClasses/state]     or
                /event[eventClasses/config]) and
                ( (/event[eventClasses/fault] and
                /event[severity="critical"]) or
                (/event[eventClasses/fault]    and
                /event[severity="major"])    or
                (/event[eventClasses/fault]    and
                /event[severity="minor"])    or
                /event[card="Ethernet0"]))
            </netconf:filter>
          </create-subscription>
        </rpc>





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7.  Security Considerations

   To be determined once specific aspects of this solution are better
   understood.  In particular, the access control framework and the
   choice of transport will have a major impact on the security of the
   solution













































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8.  IANA Considerations

   Event Classes will likely be an IANA-managed resource.  The initial
   set of values is defined in this specification.















































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9.  Acknowledgements

   Thanks to Gilbert Gagnon and Greg Wilbur for providing their input
   into the early work on this document.  In addition, the editors would
   like to acknowledge input at the Vancouver editing session from the
   following people: Orly Nicklass, James Bakstrieve, Yoshifumi
   Atarashi, Glenn Waters, Alexander Clemm, Dave Harrington, Dave
   Partain, Ray Atarashi and Dave Perkins.

10.  References

   [NETCONF]  Enns, R., "NETCONF Configuration Protocol",
              ID draft-ietf-netconf-prot-06, April 2005.

   [NETCONF BEEP]
              Lear, E. and K. Crozier, "Using the NETCONF Protocol over
              Blocks Extensible Exchange Protocol (BEEP)",
              ID draft-ietf-netconf-beep-05, March 2005.

   [NETCONF Datamodel]
              Chisholm, S. and S. Adwankar, "Framework for NETCONF
              Content", ID draft-chisholm-netconf-model-04.txt,
              October 2005.

   [NETCONF SOAP]
              Goddard, T., "Using the Network Configuration Protocol
              (NETCONF) Over the Simple Object Access Protocol (SOAP)",
              ID draft-ietf-netconf-soap-05, April 2005.

   [NETCONF SSH]
              Wasserman, M. and T. Goddard, "Using the NETCONF
              Configuration Protocol over Secure Shell (SSH)",
              ID draft-ietf-netconf-ssh-04.txt, April 2005.

   [URI]      Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifiers (URI): Generic Syntax", RFC 2396,
              August 1998.

   [XML]      World Wide Web Consortium, "Extensible Markup Language
              (XML) 1.0", W3C XML, February 1998,
              <http://www.w3.org/TR/1998/REC-xml-19980210>.

   [refs.RFC2026]
              Bradner, S., "The Internet Standards Process -- Revision
              3", RFC 2026, BCP 9, October 1996.

   [refs.RFC2119]
              Bradner, s., "Key words for RFCs to Indicate Requirements



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              Levels", RFC 2119, March 1997.

   [refs.RFC2223]
              Postel, J. and J. Reynolds, "Instructions to RFC Authors",
              RFC 2223, October 1997.

   [refs.RFC3080]
              Rose, M., "The Blocks Extensible Exchange Protocol Core",
              RFC 3080, March 2001.


Authors' Addresses

   Sharon Chisholm
   Nortel
   3500 Carling Ave
   Nepean, Ontario  K2H 8E9
   Canada

   Email: schishol@nortel.com


   Kim Curran
   Nortel
   3500 Carling Ave
   Nepean, Ontario  K2H 8E9
   Canada

   Email: kicurran@nortel.com


   Hector Trevino
   Cisco
   Suite 400
   9155 E. Nichols Ave
   Englewood, CO  80112
   USA

   Email: htrevino@cisco.com












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Appendix A.  Potential Event Content

   This non-normative appendix explores possible content of event
   notifications.  It provides field descriptions and indicates their
   applicability for the various event classes.  Fields specific to
   configuration events (configuration event class) are provided in
   Appendix B.

A.1  Event Identifier

   A unique event identifier provided for event correlation purposes.
   This field is used by management applications to identify events
   which are generated for a single event occurrence via different
   mechanisms (e.g. syslog, NETCONF).  Ie, this event identifier could
   be included as content in a syslog or SNMP message to indicate that
   all the messages were generated from the same source event.  Event Id
   values may be re-used across re-boots.

   Applicable event classes: All

A.2  Resource Instance

   This field identifies the element/entity/object for which the event
   is applicable.

   Applicable event classes: All

A.3  Event Time

   This field represents the time at which the action causing the
   generation of the event has taken place.  Event time field is
   composed of two parts: event generation time and event sysUpTime.

   Event generation time follows the syslog TIMESTAMP format defined in
   draft-ietf-syslog-protocol-14.txt (derived from RFC3339 but with
   additional restrictions).  Event sysUpTime is of XML type integer
   (0..4294967295) and it follows the same definition as sysUpTime
   (TimeTicks) defined in RFC3418 - "The time (in hundredths of a
   second) since the network management portion of the system was last
   re-initialized).

   Applicable event classes: All

A.4  Perceived Severity

   The severity of the alarm as determined by the alarm detection point
   using the information it has available [RFC3877].  The values are
   cleared, indeterminate, critical, major, minor and warning.



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   Applicable event classes: fault

A.5  Probable Cause

   This field provides further information describing the cause of the
   alarm .  Allowed values for this field are the same as those listed
   in RFC3877 and are derived from ITU X.733 and ITU M.3100.

   Note that this concept is being evolved to be less linear, within the
   ITU-T, in X.733.1, a protocol-neutral version of X.733.  It may make
   sense to consider alignment with this update on the concept of
   probable cause, instead of the one in RFC3877 and X.733.

   Applicable event classes: fault

A.6  Specific Problem

   This parameter is optional.  When present, it identifies further
   refinements to the Probable cause of the alarm.  This definition
   follows ITU X.733

   Applicable event classes: fault

A.7  Trend Indication

   This parameter indicates the trend of the alarm against the managed
   resource Allowed values for this field are as specified in RFC3877
   and follow the ITU X.733 value definitions

   Applicable event classes: fault

A.8  Additional Alarm Text

   This parameter is provided to allow implementation to include a
   textual description of the alarm

   Applicable event classes: fault

A.9  Threshold Identifier

   This field holds the identifier of the monitored variable for which
   the threshold was set.  This is analogous to the alarmVariable
   OBJECT-TYPE in RFC2819.

   Applicable event classes: fault (useful for threshold crossing
   alarms)





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A.10  Threshold Type

   This parameter is used to indicate the direction of the threshold
   crossing: rising, falling, or clear.

   Rising threshold type: This indicates that the value of a monitored
   variable has crossed the set threshold in the upwards direction.
   Only sent to indicate a problem

   Falling threshold type: This indicates that the value of a monitored
   variable has crossed the set threshold in the downwards direction.
   Only sent to indicate a problem.

   Clear threshold type: This indicates that the value of the monitored
   variable for which a threshold alarm had been previously issued as a
   result of crossing the set value either in the upwards or downwards
   direction has been restored to a value within an acceptable range
   (i.e. does not exceed the set threshold).  Note that this differs
   from RFC2819.

   Applicable event classes: fault (useful in the case threshold
   crossing alarms)

A.11  Observed Value

   The value of the monitored parameter (Threshold Identifier) for the
   last sampling period.  This parameter follows the alarmValue
   definition in RFC2819.  This field is in two parts - the value and
   the units of measure.

   Applicable event classes: fault (useful in the case threshold
   crossing alarms)

A.12  State Change Information

   This parameter holds the name and values of the state attributes
   whose values have changed and are being reported.

   This is a parameter composed of three fields: Attribute Name, Old
   Value, and New Value.  The definitions given in RFC4268 for state
   attributes and values are being followed.

   Applicable event classes: state








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Appendix B.  Configuration Event Class Notifications

   This non-normative appendix provides a detailed description of a
   configuration change event notification definition in support of the
   configuration operations, particularly those defined by the NETCONF
   protocol.

B.1  Types of Configuration Events

   Configuration event notifications include:

   o  All-triggered Configuration Events

   o  NETCONF-triggered Configuration Events

   All-triggered Configuration events report on changes from the
   perspective of the managed resource, rather than the commands which
   created the configuration change.  They are reported regardless of
   what specific method was used to initiate the change.  They indicate
   that a change has occurred around hardware, software, services or
   other managed resources within a system.  Specific events includes

   o  Resource Added

   o  Resource Removed

   o  Resource Modified

   NETCONF-triggered events are those which correspond to the execution
   of explicit NETCONF operations.  These include:

   o  copy-config event

      *  This is a data store level event generated following the
         successful completion of a copy-config operation.  This
         represents the creation of a new configuration file or
         replacement of an existing one.

   o  delete-config event

      *  This is a data store level event generated following the
         successful completion of a delete-config operation.  This
         represents the deletion of a configuration file.

   o  edit-config event

      *  This is an event generated following a change in configuration
         due to an edit-config operation, e.g., due to the completion of



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         an edit-config operation which successfully changed some part
         of the configuration.  See edit-config error-options (stop-on-
         error, ignore-error, rollback-on-error)  The contents of this
         event are dependent on the type of operation performed: edit-
         config (merge, replace, delete, create).  This event is not
         intended to report completely unsuccessful configuration
         operations.

   o  lock-config event

      *  This is a data store level event generated following the
         successful locking of a configuration data store.

   o  unlock-config event

      *  This is a data store level event generated following the
         successful release of a lock previously held on a configuration
         data store.


B.2  Config Event Notification Structure

   The table below lists the EventInfo parameters for a config event
   notification.

   Nomenclature:

   O - This is marked optional field because it is implementation/
   notification category dependent.  In some cases this may be user
   configurable.

   M - This is a mandatory field that must be included.  Dependency on
   event class may exist as noted below


















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        -----------------------------------------------------
              Parameter Name               Restrictions
        -----------------------------------------------------
               EventInfo
        -----------------------------------------------------
                  EventID                          O
        -----------------------------------------------------
                  ResourceInstance                 M
        -----------------------------------------------------
                  ConfigChangeType                 M
        -----------------------------------------------------
                  TargetDataStore                  M
        -----------------------------------------------------
                  UserInfo                         O
        -----------------------------------------------------
                     UserName
        -----------------------------------------------------
                     SourceIndicator
        -----------------------------------------------------
                     TransactionId
        -----------------------------------------------------
                  CopyConfigInfo        -- copy-config only
        -----------------------------------------------------
                     DataSource                    M
        -----------------------------------------------------
                  EditConfigInfo        -- edit-config only
        -----------------------------------------------------
                     EventTime                     M
        -----------------------------------------------------
                     Context                       O
        -----------------------------------------------------
                     EnteredCommand                M
        -----------------------------------------------------
                     NewConfig                     M
        -----------------------------------------------------
                     MergeReplaceInfo
        -----------------------------------------------------
                        OldConfig                  O
        -----------------------------------------------------
                  EventTime                        M
        -----------------------------------------------------
                      EventGenerationTime
        -----------------------------------------------------
                      EventSysUpTime
        -----------------------------------------------------






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B.3  Configuration Event Content

   The applicability of these fields to other event classes is for
   further study.

B.3.1  Target Datastore

   Target datastore refers to the data store (startup, candidate,
   running) which was modified by the management operation.

B.3.2  User Info

   This is used to convey information describing who originated the
   configuration event and the means for submitting the request.  The
   user info field contains the following information:

      user Name: User id which was authorized to execute the associated
      management operation causing the generation of this event.

      source Indicator: Indicates the method employed to initiate the
      management operation telnet, NETCONF, console, etc.

      transaction Id: If available, this field contains a unique
      identifier for the associated management operation.  This is
      implementation dependent and may require additional information to
      be communicated between server and client.  A possible option is
      to make use of the message-id in the NETCONF rpc header


B.3.3  Data Source

   The data source is used, for example, in the copy configuration
   command to indicated the source of information used in the copy
   operation

   Applicable Event Classes: configuration (useful for copy-config)

B.3.4  Operation

   Operation is used, for example, in the edit configuration command to
   indicated the specific operation that has taken place - create,
   delete, merge, replace.

   Applicable Event Classes: configuration (useful for edit-config)

B.3.5  Context

   The configuration sub-mode under which the command was executed.



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   Applicable Event Classes: configuration

B.3.6  Entered Command

   The command entered and executed on the device.

B.3.7  New Config

   The device's configuration following the successful execution of the
   entered command.

   Applicable Event Classes: configuration

B.3.8  Old Config

   The configuration prior to the execution of the entered command.

   Applicable Event Classes: configuration

B.3.9  Non-netconf commands in configuration notifications

   To support legacy implementations and for better integration with
   other deployed solutions on the box, sending information via netconf
   about configuration changes that were originated via other solutions,
   such as command line interfaces is necessary.  In order to do this,
   the information in the message needs to be clearly tagged so that the
   consumer of the information knows what to expect.  In addition, the
   creation of the subscription needs allow for the client to indicate
   whether this non-XML formatted information is of interest

   The latter is done by identifying the XML namespace under which the
   data syntax/schema is defined.  A NETCONF client requests the format
   in which it wants the NETCONF server to issue the event notifications
   at subscription time by specifying the appropriate namespace under
   the Filter parameter in the  <create-subscription>  operation.  An
   example is provided below:

          <netconf:filter>
             <data-format:config-format-xml
                           xmlns="http://www.example.com/xmlnetevents"/>
          </netconf:filter>


B.4  Design Alternative

B.4.1  Server Session Initiation

   Currently the NETCONF protocol requires session establishment to be



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   initiated by the NETCONF client.  With the introduction of event
   notifications in NETCONF as well deployments which might require the
   "call-home" feature to get around firewall and/or NAT issues, the
   ability for a NETCONF server to initiate sessions becomes important.

   Other potential uses of this feature includes the following
   deployment scenario: NE registration/auto-configuration.  The device
   is pre-configured with a target destination address (the management
   station's address) where it needs to register and download its
   configuration.  When managing large numbers of devices (e.g.  CPEs)
   this also allows for increased scalability since the management
   station does not need to maintain established sessions to all managed
   devices.

   This appendix proposes extensions to the event subscription session
   establishment procedures and related operations to allow for server
   session initiation.

   Note that the security implications of this approach, compared with
   more traditional, well understood models, is for further study.

   The subscription information as described in the body of this
   document indicates that it is transient in nature (i.e. it is not
   persisted and it is only applicable through the life of the session).
   This section describes additional functionality for persisting event
   subscription information and allowing the NETCONF server (e.g.
   network element) to initiate the event subscription session.

   QUICK SUMMARY:  The <create-subscription>, <cancel-subscription>,
   <modify-subscription> operations would be used in same manner as
   described in doc.  It may use useful to allow a client and server to
   re-establish an events subscription.  This would result in another
   capability to allow session initiation by the server.

B.4.2  Establishment

   In order to establish an event subscription, a client must issue a
   <create-subscription> message request.  Upon a successful response
   from the server (e.g. network element) the event subscription is
   established.  With this modified persistent version of the
   subscription, the NETCONF server would maintain the subscription
   information as part of its configuration.

B.4.3  Teardown

   A event subscription is torn down when a) the client issues a
   <cancel-subscription>  message and it is successfully processed by
   the server (i.e. the server issues a positive response) or b) the



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   NETCONF session carrying the event subscription goes down for any
   reason.

   If the subscription is not persistent, the user must create a new
   subscription with the exact same parameters as the original session.
   If instead, subscriptions were persistent, as part of the network
   element's configuration, the client simply needs to re-establish the
   session by specifying the subscription Id.

B.4.4  Suspend And Resume

   Since the purpose of the <cancel-subscription> operation is to stop
   event notification forwarding and due to its transient nature removes
   all subscription configuration; a different mechanism might be needed
   for shutting down the session but preserving the subscription
   information thus allowing the NETCONF server to re-establish the
   parameters and reproduce the subscription.

   The suspend and resume commands would allows a NETCONF client to
   suspend event notification forwarding without removing the existing
   subscription information.  Operations <suspend-subscription> and
   ><resume-subscription> are proposed for this purpose.

   Since event subscription information is now persistent, unsolicited
   session termination (i.e. other than <cancel-subscription))  is
   treated as if a  <suspend-subscription>  command was issued.  Event
   forwarding is resumed by sending a <resume-subscription> to the
   NETCONF server on a new connection.

B.4.5  Lifecycle

   Configuration information associated with the event subscription
   (event classes and  filters) could persist beyond the life of the
   event subscription session. (i.e. it is maintained by the network
   element as part of its configuration).  This configuration
   information is subject to the behaviour of the datastore it resides
   in and may or may not persist across re-boots (e.g. it could be part
   of the running configuration but not the startup configuration).













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Appendix C.  NETCONF Event Notifications and Syslog

   This appendix describes the mapping between syslog message fields and
   NETCONF event notification fields.  The purpose of this mapping is to
   provide an unambiguous mapping to enable consistent multi-protocol
   implementations as well as to enable future migration.

   The second part of the appendix describes an optional capability to
   embed an entire syslog message (hereafter referred to as syslog
   message(s) to avoid confusion with the message field in syslog)
   within a NETCONF event notification.

C.1  Leveraging Syslog Field Definitions

   This section provides a semantic mapping between NETCONF event fields
   and syslog message fields.

     -------------------------------------------------------------------
     |         PRI         |          HEADER         |    MESSAGE      |
     -------------------------------------------------------------------
     | FACILITY | SEVERITY |  TIMESTAMP  | HOSTNAME  |  TAG CONTENT    |
     -------------------------------------------------------------------
                    Figure 2 - syslog message (RFC3164)


     -------------------------------------------------------------------
    |     HEADER         |    STRUCTURED DATA         |    MESSAGE     |
     -------------------------------------------------------------------
         Figure 3 - syslog message (draft-ietf-syslog-protocol-14.txt)

   HEADER (Version, Facility, Severity, Truncate, Flag, TimeStamp,
           HostName, AppName, ProcId, MsgId)

       STRUCTURED DATA (Zero or more Structured Data Elements - SDEs)

        MESSAGE ( Text message )















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C.1.1  Field Mapping

   ------------------------------------------------------
     RFC3164      Syslog ID       NETCONF Event
   ------------------------------------------------------
                   VERSION
   ------------------------------------------------------
     FACILITY      FACILITY
   ------------------------------------------------------
     SEVERITY      SEVERITY        PerceivedSeverity
   ------------------------------------------------------
                   TRUNCATE FLAG
   ------------------------------------------------------
     TIMESTAMP     TIMESTAMP       EventTime
   ------------------------------------------------------
     HOSTNAME      HOSTNAME        EventOrigin
   ------------------------------------------------------
     TAG           APP-NAME        EventOrigin
   ------------------------------------------------------
                   PROC-ID
   ------------------------------------------------------
                   MSG-ID
   ------------------------------------------------------
     CONTENT       CONTENT         AdditionalText
   ------------------------------------------------------

        Figure 4 - syslog to NETCONF Event field mapping

   Notes:

   VERSION:  Schema version is found in XML Schema namespace.  However,
   no correspondence to syslog.

   FACILITY: No well defined semantics for this field.  Therefore not
   used at this time.

   TRUNCATE: Not applicable.  NETCONF events must be complete XML
   documents therefore cannot be truncated.

   TIME: TIMESTAMP in syslog ID is derived from RFC3339 but with
   additional restrictions

   PROC-ID: No equivalent field

   CONTENT: This is a free form text field with not defined semantics.
   The contents of this field may be included in the AdditionalText
   field.




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C.1.2  Severity Mapping

   The severity value mappings stated in (draft-ietf-syslog-protocol-14)
   are used:

                 ITU Perceived Severity      syslog SEVERITY
                 Critical                    Alert
                 Major                       Critical
                 Minor                       Error
                 Warning                     Warning
                 Indeterminate               Notice
                 Cleared                     Notice

      Figure 5. ITU PerceivedSeverity to syslog SEVERITY mapping.


C.2  Syslog within NETCONF Events

C.2.1  Motivation

   The syslog protocol (RFC3164) is widely used by equipment vendors as
   a means to deliver event messages.  Due to the widespread use of
   syslog as well as a potential phased availability and coverage of
   NETCONF events by equipment vendors, it is envisioned that users will
   also follow a phased migration.  As a way to facilitate migration and
   at the same time allow equipment vendors to provide comprehensive
   event coverage over a NETCONF event subscription session, syslog
   messages could be embedded in their entirety within the body of a
   NETCONF event notification.

   The information provided in this appendix describes a mechanism to
   leverage syslog messages for the purpose of complementing the
   available NETCONF event notification set.  The intent is to promote
   the use of the NETCONF interface and not to simply provide a wrapper
   and additional delivery mechanism for syslog messages.  NETCONF
   events are intended to be well defined and structured, therefore
   providing an advantage over the unstructured and often times
   arbitrarily defined syslog messages (i.e. the message field).

   Covered herein is the syslog protocol as defined in RFC3164 and
   draft-ietf-syslog-protocol-14.txt.

C.2.2  Embedding syslog messages in a NETCONF Event

   When event notifications are supported, the default behaviour for a
   NETCONF server is to send NETCONF event notifications over an
   established event subscription.  As an option, the NETCONF server may
   embed a syslog message in its entirety (e.g.  RFC3164 - PRI, Header,



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   and Message fields), placing it within the Event Info field
   (SyslogInfo sub-field) - see Figure 1.

   _____________________________________________________
   | NETCONF Event  Header         |           Data            |
   |________________________|___________________________|
   |                        |         Event Info        |
   |________________________|___________________________|
                            |                           |
                            v                           v
                             ____________________________
                            | Event Fields | SyslogInfo |
                            |___________________________|


   Figure 1 - Embedding syslog in a NETCONF Event Notifications


C.2.3  Supported Forwarding Options

   Three event forwarding options may be supported by the NETCONF
   server: a) XML only (mandatory if NETCONF events capability is
   supported) b) XML and syslog (Optional) c) syslog only (optional)

   Note to the reader: Option "a" above refers to event notification
   messages defined for use over the NETCONF protocol.  While their use
   is not necessarily limited to NETCONF protocol, they are referred to
   as "NETCONF XML-event" in the remainder of this section simply to
   avoid ambiguity.

C.2.3.1  XML and Syslog option - Forwarding Behaviour

   It is possible, due to coverage, for a given NETCONF implementation
   to not support a comprehensive set of NETCONF event notifications.
   Therefore, it is possible for a given event to trigger the generation
   of a syslog message without a NETCONF-aware counterpart.  In such
   situations, the NETCONF server could form a NETCONF event
   notification, embed the syslog message in the SyslogInfo field and
   forward the NETCONF event notifications to all subscribed
   destinations.  Otherwise, both NETCONF event and syslog messages must
   be included in the Event Info field.

C.2.3.2  Event Class Identification

   The event class field is found in the NETCONF event header
   information as described in the main body of this document.  It
   conveys information describing that type of event for which the event
   notification is generated and lets the consumer of the message know



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   what to expect.  NETCONF event notifications which only contain a
   syslog message (Options b or c) must have the EventClass field set to
   "information".  [Editor's Note: This needs to be thought through.  It
   may not be the best option.]  The NETCONF client parses the message
   in the same manner as any other message, finds the normal fields
   empty [Editor's Note: or not present?] and either proceeds to parse
   the SyslogInfo field or hands the syslog message to the entity
   responsible for processing syslog messages.

C.2.3.3  Event Subscription Options

   A NETCONF client may request subscription to options b) XML and
   syslog or c) syslog only listed in "Supported Forwarding Options" at
   subscription time via the user-specified filter.  The FILTER or NAMED
   FILTER parameter in <create-subscription>.  As previously indicated,
   the default behaviour is to forward NETCONF XML only event
   notifications.

C.2.3.4  Supported Forwarding Option Discovery

   A potential means for a NETCONF server to convey its feature set
   support is via capabilities.  However, in this particular case, the
   event content is not a protocol feature therefore other means are
   needed.  A future version of this document will address this issue.



























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   This document and the information contained herein are provided on an
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   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
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Copyright Statement

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   except as set forth therein, the authors retain all their rights.





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Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.















































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