Network Working Group                                        S. Chisholm
Internet-Draft                                                 K. Curran
Expires: July 12, October 30, 2006                                         Nortel
                                                              H. Trevino
                                                                   Cisco
                                                         January 8,
                                                          April 28, 2006

                      NETCONF Event Notifications
                 draft-ietf-netconf-notification-00.txt
                 draft-ietf-netconf-notification-01.txt

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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.

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 . . . . . .   Event Notification . . . . . . . . . . . . . . . . . .  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 Notification Messages  . . . . . . . . . . . . . . . . . . . 14 16
     3.4   User-Specified Filters   Filter Dependencies  . . . . . . . . . . . . . . . . . . 14 . 16
       3.4.1   Named Profiles . . . . . . . . . . . . . . . . . . . . 15 17
       3.4.2   Filtering  . . . . . . . . . . . . . . . . . . . . . . 15 17
     3.5   Event Classes  . . . . . . . . . . . . . . . . . . . . . . 15 17
     3.6   Defining Event Notifications . . . . . . . . . . . . . . . 16 18
     3.7   Interleaving Messages  . . . . . . . . . . . . . . . . . . 16 18
   4.  XML Schema for Event Notifications . . . . . . . . . . . . . . 18 20
   5.  Mapping to Application Protocols . . . . . . . . . . . . . . . 23 24
     5.1   SSH  . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 24
     5.2   BEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 25
       5.2.1   One-way Notification Messages in Beep  . . . . . . . . . . . . . . . 24 25
     5.3   SOAP . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 26
       5.3.1   A NETCONF over Soap over HTTP Example  . . . . . . . . 25 26
   6.  Filtering examples . . . . . . . . . . . . . . . . . . . . . . 28 29
     6.1   Event Classes  . . . . . . . . . . . . . . . . . . . . . . 28 29
     6.2   Subtree Filtering  . . . . . . . . . . . . . . . . . . . . 28 29
     6.3   XPATH filters  . . . . . . . . . . . . . . . . . . . . . . 30 31
   7.  Security Considerations  Additional Capabilities  . . . . . . . . . . . . . . . . . . . 32
   8.  IANA Considerations 33
     7.1   Call-Home Notifications  . . . . . . . . . . . . . . . . . 33
       7.1.1   Overview . . . . 33
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . 33
       7.1.2   Dependencies . . . . . . 34
   10.   References . . . . . . . . . . . . . . . 34
       7.1.3   Capability Identifier  . . . . . . . . . . . . . . . . 34
       Authors' Addresses
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 37
   9.  IANA Considerations  . . . . 35
   A.  Potential Event Content . . . . . . . . . . . . . . . . . 38
   10.   Acknowledgements . . 36
     A.1   Event Identifier . . . . . . . . . . . . . . . . . . . . 39
   11.   References . 36
     A.2   Resource Instance . . . . . . . . . . . . . . . . . . . . 36
     A.3   Event Time . . . . 39
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 36
     A.4   Perceived Severity . 40
   A.  Design Alternatives  . . . . . . . . . . . . . . . . . . . 36
     A.5   Probable Cause . . 41
     A.1   Suspend And Resume . . . . . . . . . . . . . . . . . . . . 37
     A.6   Specific Problem 41
     A.2   Lifecycle  . . . . . . . . . . . . . . . . . . . . . 37
     A.7   Trend Indication . . . 41
   B.  Event Notifications and Syslog . . . . . . . . . . . . . . . . 42
     B.1   Leveraging Syslog Field Definitions  . . 37
     A.8   Additional Alarm Text . . . . . . . . . 42
       B.1.1   Field Mapping  . . . . . . . . . . . . 37
     A.9   Threshold Identifier . . . . . . . . 43
       B.1.2   Severity Mapping . . . . . . . . . . . . 37
     A.10  Threshold Type . . . . . . . 44
     B.2   Syslog within NETCONF Events . . . . . . . . . . . . . . . 38
     A.11  Observed Value 44
       B.2.1   Motivation . . . . . . . . . . . . . . . . . . . . . . 38
     A.12  State Change Information 44
       B.2.2   Embedding syslog messages in a NETCONF Event . . . . . 44
       B.2.3   Supported Forwarding Options . . . . . . . . . . . . 38
   B. . 45
   C.  Example Configuration Event Class Notifications  . . . . . . . . . . . 39
     B.1 . . 47
     C.1   Types of Configuration Events  . . . . . . . . . . . . . . 39
     B.2 47
     C.2   Config Event Notification Structure  . . . . . . . . . . . 40
     B.3 48
     C.3   Configuration Event Content  . . . . . . . . . . . . . . . 42
       B.3.1 50
       C.3.1   Target Datastore . . . . . . . . . . . . . . . . . . . 42
       B.3.2 50
       C.3.2   User Info  . . . . . . . . . . . . . . . . . . . . . . 42
       B.3.3 50
       C.3.3   Data Source  . . . . . . . . . . . . . . . . . . . . . 42
       B.3.4 50
       C.3.4   Operation  . . . . . . . . . . . . . . . . . . . . . . 42
       B.3.5 50
       C.3.5   Context  . . . . . . . . . . . . . . . . . . . . . . . 42
       B.3.6 50
       C.3.6   Entered Command  . . . . . . . . . . . . . . . . . . . 43
       B.3.7 51
       C.3.7   New Config . . . . . . . . . . . . . . . . . . . . . . 43
       B.3.8 51
       C.3.8   Old Config . . . . . . . . . . . . . . . . . . . . . . 43
       B.3.9 51
       C.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  . . . . . . . . . . . . 51
       Intellectual Property and Copyright Statements . . . . . . . . 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 52

1.  Introduction

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

   Layer                      Example
    +-------------+      +-----------------------------+      +----------------------------------------+
    |   Content   |      |     Configuration data                 |
    +-------------+      +-----------------------------+      +----------------------------------------+
              |                           |
    +-------------+      +-----------------------------+      +-------------------------------------------+
    | Operations  |      | <get-config>, <edit-config> | <notification>|
    +-------------+      +-----------------------------+      +-------------------------------------------+
              |                           |                    |
    +-------------+      +-----------------------------+       |
    |     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.

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.

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
         An optional parameter that points to a separately defined
         filter profile.  If not present, no additional filtering  The contents of the profile are specified in
         the provided XML Schema.  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  Event Notification

   <notification>

   Description:

      An event notification is sent to the initiator of an <create-
      subscription>  command asynchronously when an event of interest
      (i.e. meeting the specified filtering criteria) 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
      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 Notification Header                                      || Data |
   ||__________________________________________________________||______|
   || subscriptionId| eventClasses| sequenceNumber| dataAndTime|| dateAndTime||      |
   ||_______________|_____________|_______________|____________||______|

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 cancelling and
   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.  The contents of the profile are specified in provided
         XML Schema.  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:

      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

      Stop and delete  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.

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"
       xmlns:nsub="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:netconf="urn:ietf:params:xml:ns:netconf:base:1.0"
      xmlns:ncEvent= "urn:ietf:params:xml:ns:netconf:notification:1.0"
     xmlns:nm="urn:ietf:params:xml:ns:netconf:appInfo:1.0"
     elementFormDefault="qualified" attributeFormDefault="unqualified"
             xml:lang="en">
        <annotation>
                       <documentation
        <xs:annotation>
                       <xs:documentation xml:lang="en">
                     Schema for reporting on Event Subscriptions
         </documentation>
         <appinfo>
         </xs:documentation>
         <xs: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:Name>NetConfStateSchema</nm:Name>
               <nm:LastUpdated>2006-04-30T09:30:47-05:00
               </nm:LastUpdated>
               <nm:Organization>IETF</nm:Organization>
               <nm:Description>
                  A schema that can be used to learn about current
                  NetConf Event Subscriptions subscriptions and creating named
                  profiles
               </nm:Description>
             </nm:identity>
           </appinfo>
              </annotation>
           </xs:appinfo>
              </xs: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"/>
            namespace="urn:ietf:params:xml:ns:netconf:notifications:1.0"
            schemaLocation="draft-ietf-netconf-notification-01.xsd"/>
       <xs:import namespace="urn:ietf:params:xml:ns:netconf:base:1.0"
                   schemaLocation="draft-ietf-netconf-prot-09.xsd"/>
                   schemaLocation="draft-ietf-netconf-prot-12.xsd"/>

      <xs:element name="netconfSubscription">
        <xs:annotation>
            <xs:appinfo>
              <nm:minAccess><read/></nm:minAccess>
              <nm:maxAccess><read/></nm:maxAccess>
            </xs:appinfo>
        </xs:annotation>
        <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>

          <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 applied.
              </xs:documentation>
                         </xs:annotation>
              <xs:keyref name="namedProfileKeyRef"
                         refer="nsub:namedProfileKey">
                <xs:selector xpath=".//namedProfile"/>
                <xs:field xpath="namedProfile"/>
              </xs:keyref>
          </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">
              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:element name="key">
            <xs:key name="uniqueSubscription">
              <xs:selector xpath=".//subscription"/>
              <xs:field xpath="session-id"/>
              <xs:field xpath="subscriptionID"/>
            </xs:key>
          </xs:element>
         </xs:sequence>
         </xs:complexType>
         </xs:element>

     <xs:element name="netconfSubscriptions">
       <xs:complexType>
       <xs:sequence>
         <xs:element ref="nsub:netconfSubscription" minOccurs="0"
                                 maxOccurs="unbounded" />
         </xs:sequence>
       </xs:complexType>
     </xs:element>

      <xs:element name="namedProfile">
        <xs:annotation>
          <xs:appinfo>
            <nm:minAccess><read/></nm:minAccess>
            <nm:maxAccess><read/> <write/> <create/> <delete/>
             </nm:maxAccess>
          </xs:appinfo>
        </xs:annotation>
        <xs:complexType>
            <xs:sequence>
              <xs:element name="name"/>
              <xs:element name="eventClasses">
                <xs:annotation>
                  <xs:documentation xml:lang="en">
                    The event classes associated with this named
                     Profile.
                  </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 named Profile.
                  </xs:documentation>
                </xs:annotation>
              </xs:element>

              <xs:element name="lastModified" type="xs:dateTime">
                <xs:annotation>
                  <xs:documentation>
                    The timestamp of the last modification to this
                     named Profile. Note that modification of the
                     profile does not cause an immediate update
                     to all applicable subscription. Therefore, this
                     time should be compared with the last
                     modified time associated with the subscription.
                     If this time is earlier, then the subscription
                      is using the exact set of parameters associated
                      with this named profile.  If this time is
                     later, then the subscription is using an earlier
                     version of this named profile and the exact
                     parameters may not match.
                  </xs:documentation>
                  <xs:appinfo>
                    <nm:minAccess><read/></nm:minAccess>
                    <nm:maxAccess><read/> </nm:maxAccess>
                  </xs:appinfo>
                </xs:annotation>
              </xs:element>

              <xs:element name="key">
                  <xs:key name="namedProfileKey">
                    <xs:selector xpath="*/name" />
                    <xs:field xpath="name" />
                  </xs:key>
              </xs:element>
            </xs:sequence>
        </xs:complexType>
      </xs:element>

      <xs:element name="namedProfiles">
         <xs:complexType>
          <xs:sequence>
            <xs:element ref="nsub:namedProfile" minOccurs="0"
                                  maxOccurs="unbounded" />
          </xs:sequence>
           </xs:complexType>
       </xs:element>
       </xs:schema>

3.3  RPC  One-way Notification 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
   notifications, which are one-way RPC message.

   The  messages.

   A 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 message will originate from the NETCONF server,
   and not the NETCONF client.

3.4  User-Specified Filters  Filter Dependencies

   Note that when multiple filters are specified, specified (Event Class, in-line
   Filter, Named Profiles), they are applied 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  notification for its value to be checked, checked against,
   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  These filters 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 information, heartbeat
   and
   heartbeat. syslog.

   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).

   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

   The syslog event class is used to indicate tunneled syslog content.
   The content and format of the message will be compliant to syslog
   standards.

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

   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 by sending 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>              |
                             |<--------------------------|

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

      </xs:schema>

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  event 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
   notification 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: the following.  Note the event notification contents
   (delimited by <data> </data> tags) are not defined in this document
   and are provided herein simply for illustration purposes:

       <?xml version="1.0" encoding="UTF-8"?>
       <rpc-one-way message-id="105"
          <notification
                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 Notification Messages in Beep

   One-way notification messages can be supported either by mapping to
   the existing one-to-many BEEP construct or by creating a new one-to-none 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", "notification", "rpc-reply"

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

5.2.1.2  One-way notification 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
      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:     <notification
                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>
      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>

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)))
        <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)))
        <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)))
        <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>

7.  Security Considerations

   To  Additional Capabilities

7.1  Call-Home Notifications

7.1.1  Overview

   Call-Home Notifications are an alternative model for providing
   notifications that may be determined once specific aspects of preferred for two particular use cases.
   The first use case is NAT traversal as in this solution are better
   understood.  In particular, model, the access control framework and Netconf
   server initiates the
   choice Notification session.  The second use case is
   when a manager has a large number of transport will have low-priority devices that it
   only wants to deal with when there a major impact on the security known issue.  While this risks
   loss of the
   solution

8.  IANA Considerations

   Event Classes will likely be information, for this particular use case, this is not
   considered an IANA-managed resource. issue.  The initial
   set Call-home-Notification feature supports the
   concept of values a short-lived notification session that only exists when
   there is defined in this specification.

9.  Acknowledgements

   Thanks something to Gilbert Gagnon report.

   In this feature, a subscription consists of a named profile, and Greg Wilbur for providing their input
   into the early work an
   association with a Netconf client.  Unlike normal subscriptions,
   which only exist when they are active, these subscriptions live while
   both dormant and active.  When an event of interest happens on this document.  In addition, the editors would
   like to acknowledge input at
   managed resource, the Vancouver editing session from Netconf server checks the
   following people: Orly Nicklass, James Bakstrieve, Yoshifumi
   Atarashi, Glenn Waters, Alexander Clemm, Dave Harrington, Dave
   Partain, Ray Atarashi list of dormant
   subscriptions and Dave Perkins.

10.  References

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

   [NETCONF BEEP]
              Lear, E. if the filtering parameters in the subscription
   indicate interest in the Notification resulting from the event, then
   the Netconf server initiates the connection to the specific Netconf
   client and K. Crozier, "Using sends the NETCONF Protocol over
              Blocks Extensible Exchange Protocol (BEEP)",
              ID draft-ietf-netconf-beep-05, March 2005.

   [NETCONF Datamodel]
              Chisholm, S. Notification.  When the Notification has been
   sent, the connection is terminated.

7.1.1.1  Session Lifecycle

   In order to avoid situations in which a sessions is continuously
   setup and S. Adwankar, "Framework for NETCONF
              Content", ID draft-chisholm-netconf-model-04.txt,
              October 2005.

   [NETCONF SOAP]
              Goddard, T., "Using torn down, an inactivity timer is configured on the Network Configuration Protocol
              (NETCONF) Over server.
   The timeout interval value is the Simple Object Access Protocol (SOAP)",
              ID draft-ietf-netconf-soap-05, April 2005.

   [NETCONF SSH]
              Wasserman, M. same for all sessions (i.e. system
   wide) and T. Goddard, "Using each session has its own timer.  Upon expiration of the NETCONF
              Configuration Protocol over Secure Shell (SSH)",
              ID draft-ietf-netconf-ssh-04.txt, April 2005.

   [URI]      Berners-Lee, T., Fielding, R.,
   inactivity timer, the connection is terminated, otherwise if activity
   is detected, the timer is reset.

   [Editor's note: alternatives here were to either create 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 tear down
   the session for RFCs each notification received or to Indicate Requirements
              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

Appendix A.  Potential Event Content

   This non-normative appendix explores possible content of event
   notifications.  It provides field descriptions and indicates their
   applicability for have 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 server
   somehow figure out that there are generated for more notifications coming soon
   after it has sent a single event occurrence via different
   mechanisms (e.g. syslog, NETCONF).  Ie, this event identifier could
   be included notification and therefore keeps the connection
   up.]

   The session establishment procedure is as content in follows:

   1)	The NETCONF server initiates a syslog or SNMP message session using a recognized
   application protocol (SSH, Beep, SOAP, etc).  In order to indicate that
   all the messages were generated from the same source event.  Event Id
   values "activate"
   this reverse behaviour a new SSH subsystem may need to be re-used across re-boots.

   Applicable event classes: All

A.2  Resource Instance defined.

   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 for further study.  In addition, the action causing NE hosting the
   generation of NETCONF
   server must support both client and server modes in the event has taken place.  Event time field is
   composed case of two parts: event generation time SSH.

   2)	Client and event sysUpTime.

   Event generation time follows server are authenticated according to 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 underlying
   application protocol (e.g.  SSH, BEEP)

   3)	If using BEEP, as sysUpTime
   (TimeTicks) defined described in RFC3418 - "The time (in hundredths of a
   second) since [NETCONF-BEEP] either party may
   initiate the network management portion of BEEP session.  Once this occurs, the system was last
   re-initialized).

   Applicable event classes: All

A.4  Perceived Severity

   The severity of assumption is that
   both parties know their roles.  At this point, the alarm as determined by NETCONF client,
   initiates NETCONF session establishment whether running SSH or BEEP.

7.1.2  Dependencies

   This feature is dependant on the alarm detection point
   using named profiles concept from the information it has available [RFC3877].  The values are
   cleared, indeterminate, critical, major, minor and warning.

   Applicable event classes: fault

A.5  Probable Cause

   This field provides further information describing
   normal subscription method as well as the cause definition of the
   alarm .  Allowed values for this field are
   <notification>.

   It also uses the same as those listed
   in RFC3877 and are derived from ITU X.733 and ITU M.3100.

   Note  <notification>

7.1.3  Capability Identifier

   urn:ietf:params:xml:ns:netconf:callHomeNotification:1.0

7.1.3.1  New Operations

7.1.3.1.1  New Data Model

   <xs:schema
      xmlns:xs="http://www.w3.org/2001/XMLSchema"
      xmlns:nsub="urn:ietf:params:xml:ns:netconf:subscription:1.0"
      targetNamespace=
              "urn:ietf:params:xml:ns:netconf:callHomeSubscription:1.0"
      xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0"
      xmlns:ncEvent= "urn:ietf:params:xml:ns:netconf:event:1.0"
      xmlns:nm="urn:ietf:params:xml:ns:netconf:appInfo:1.0"
      elementFormDefault="qualified"
                     attributeFormDefault="unqualified" xml:lang="en">
   <xs:annotation>
     <xs:documentation xml:lang="en">
          Schema for reporting on dormant Call-Home Notification
          Subscriptions
     </xs:documentation>
      <xs:appinfo>
          <nm:identity
                  xmlns:nm="urn:ietf:params:xml:ns:netmod:base:1.0">
                <nm:Name>NetConfCallHomeSchema</nm:Name>
                 <nm:LastUpdated>2006-04-30T09:30:47-05:00
                 </nm:LastUpdated>
                 <nm:Organization>IETF</nm:Organization>
                  <nm:Description>
                       A schema that this concept is being evolved can be used to learn about callHome
                       Notification subscriptions
                   </nm:Description>
            </nm:identity>
     </xs:appinfo>
    </xs:annotation>

   <xs:import
      namespace="urn:ietf:params:xml:ns:netconf:subscription:1.0"
      schemaLocation="urn:ietf:params:xml:ns:netconf:subscription:1.0"/>

    <xs:element name="callHomeSubscription">
        <xs:annotation>
               <xs:appinfo>
                    <nm:minAccess><read/></nm:minAccess>
                    <nm:maxAccess><read/></nm:maxAccess>
               </xs:appinfo>
       </xs:annotation>
       <xs:complexType>
             <xs:sequence>
                   <xs:element name="subscriber" type="xs:string">
                         <xs:annotation>
                             <xs:documentation>
                               This needs to be less linear, within the
   ITU-T, in X.733.1, replaced with a protocol-neutral version of X.733.  It may make
   sense to consider alignment more
                               prescriptive data type
                             </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 update on
                               subscription. Note that the concept of
   probable cause, instead
                               contents of the one in RFC3877 and X.733.

   Applicable event classes: fault

A.6  Specific Problem

   This parameter is optional.  When present, named profile may have
                               changed since 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. last applied
                             </xs:documentation>
                         </xs:annotation>
                         <xs:keyref refer="nsub:namedProfileKey"
                             name="namedProfileKeyRef">
                             <xs:selector xpath=".//namedProfile">
                              </xs:selector>
                             <xs:field xpath="namedProfile"></xs:field>
                         </xs:keyref>
                     </xs:element>

                     <xs:element name="status">
                           <xs:simpleType>
                             <xs:restriction base="xs:string">
                               <xs:enumeration value="Dormant"/>
                               <xs:enumeration value="Active"/>

                             </xs:restriction>
                           </xs:simpleType>

                         </xs:element>

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

                   </xs:element>

                 </xs:schema>

7.1.3.1.2  Modifications to Existing Operations

7.1.3.1.2.1   <create-subscription>

   This is analogous capability adds a new attribute to the alarmVariable
   OBJECT-TYPE in RFC2819.

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

A.10  Threshold Type <create-subscription>
   command.  This attribute is

   callHome:

   An optional parameter that, when present, indicates whether this will
   be a call-home Notification subscription.  If not present, this will
   be a normal subscription.

7.1.3.1.3  Interactions with Other Capabilities

   It is used to indicate only when these subscriptions move from the direction of dormant state to
   the threshold
   crossing: rising, falling, or clear.

   Rising threshold type: This indicates active state that they have sessions associated with them.  It is
   only at this point that they show up in the value active subscription list.

8.  Security Considerations

   To be determined once specific aspects of a monitored
   variable has crossed this solution are better
   understood.  In particular, the set threshold in access control framework and the upwards direction.
   Only sent to indicate
   choice of transport will have a problem

   Falling threshold type: This indicates that major impact on the value security of a monitored
   variable has crossed the
   solution

9.  IANA Considerations

   Event Classes will likely be an IANA-managed resource.  The initial
   set threshold of values is defined in the downwards direction.
   Only sent this specification.

10.  Acknowledgements

   Thanks to indicate a problem.

   Clear threshold type: This indicates that the value of the monitored
   variable Gilbert Gagnon and Greg Wilbur for which a threshold alarm had been previously issued as a
   result of crossing the set value either in providing their input
   into 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 early work on 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 document.  In addition, the
   last sampling period.  This parameter follows editors would
   like to acknowledge input at the alarmValue
   definition in RFC2819.  This field is in two parts - Vancouver editing session from the value
   following people: Orly Nicklass, James Bakstrieve, Yoshifumi
   Atarashi, Glenn Waters, Alexander Clemm, Dave Harrington, Dave
   Partain, Ray Atarashi 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 Dave Perkins.

11.  References

   [NETCONF]  Enns, R., "NETCONF Configuration Protocol",
              ID draft-ietf-netconf-prot-12, February 2006.

   [NETCONF BEEP]
              Lear, E. and values of K. Crozier, "Using the state attributes
   whose values have changed and are being reported.

   This is a parameter composed of three fields: Attribute Name, Old
   Value, NETCONF Protocol over
              Blocks Extensible Exchange Protocol (BEEP)",
              ID draft-ietf-netconf-beep-10, March 2006.

   [NETCONF Datamodel]
              Chisholm, S. and New Value.  The definitions given in RFC4268 S. Adwankar, "Framework for state
   attributes and values are being followed.

   Applicable event classes: state

Appendix B. NETCONF
              Content", ID draft-chisholm-netconf-model-05.txt,
              April 2006.

   [NETCONF SOAP]
              Goddard, T., "Using the Network Configuration Event Class Notifications

   This non-normative appendix provides a detailed description of a
   configuration change event notification definition in support of Protocol
              (NETCONF) Over the
   configuration operations, particularly those defined by Simple Object Access Protocol (SOAP)",
              ID draft-ietf-netconf-soap-08, March 2006.

   [NETCONF SSH]
              Wasserman, M. and T. Goddard, "Using 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 Protocol over Secure Shell (SSH)",
              ID draft-ietf-netconf-ssh-06.txt, March 2006.

   [URI]      Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Modified

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

   o  copy-config event

      *  This is a data store level event generated following the
         successful completion Indicate Requirements
              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

Appendix A.  Design Alternatives

A.1  Suspend And Resume

   The purpose 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 <cancel-subscription> operation is a data store level to stop event generated following the
         successful completion of a delete-config operation.  This
         represents
   notification forwarding and since the deletion of a configuration file.

   o  edit-config event

      *  This notification subscription is an event generated following a change in configuration
         due to an edit-config operation, e.g., due to
   transient the completion of
         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 naturally  removes all subscription
   configuration; For this
         event are dependent on reasons, a different mechanism might be
   needed for shutting down the type of operation performed: edit-
         config (merge, replace, delete, create).  This event is not
         intended notification session but preserving the
   subscription information thus allowing the NETCONF server to report completely unsuccessful configuration
         operations.

   o  lock-config event

      *  This is a data store level event generated following re-
   establish the parameters and reproduce the
         successful locking of a configuration data store.

   o  unlock-config event

      *  This is notification subscription.

   The suspend and resume commands would allows a data store level NETCONF client to
   suspend event generated following notification forwarding without removing the
         successful release of a lock previously held existing
   subscription information.  It could be used for both subscriptions
   based on a configuration
         data store.

B.2  Config Event Notification Structure

   The table below lists the EventInfo parameters persistent and non-persistent subscription information.
   Operations <suspend-subscription> and  ><resume-subscription> are
   proposed for a config this purpose.

   If event
   notification.

   Nomenclature:

   O - This subscription information is marked optional field because it now persistent, unsolicited
   session termination (i.e. other than <cancel-subscription))  is implementation/
   notification category dependent.  In some cases this may be user
   configurable.

   M - This
   treated as if a  <suspend-subscription>  command was issued.  Event
   forwarding is resumed by sending a mandatory field that must be included.  Dependency <resume-subscription> to the
   NETCONF server on
   event class may exist as noted below
        -----------------------------------------------------
              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
        -----------------------------------------------------

B.3 a new connection.

A.2  Lifecycle

   Configuration Event Content

   The applicability of these fields to other information associated with the event subscription
   (event classes is for
   further study.

B.3.1  Target Datastore

   Target datastore refers to and  filters) could persist beyond the life of the data store (startup, candidate,
   running) which was modified
   event subscription session. (i.e. it is maintained by the management operation.

B.3.2  User Info network
   element as part of its configuration).  This configuration
   information is used subject to convey information describing who originated the
   configuration event and the means for submitting behaviour of the request.  The
   user info field contains datastore it resides
   in and may or may not persist across re-boots (e.g. it could be part
   of the following information:

      user Name: User id which was authorized to execute running configuration but not the associated
      management operation causing startup configuration).

Appendix B.  Event Notifications and Syslog

   This appendix describes the generation mapping between syslog message fields and
   NETCONF event notification fields.  The purpose of this event.

      source Indicator: Indicates 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 method employed appendix describes an optional capability to initiate
   embed an entire syslog message (hereafter referred to as syslog
   message(s) to avoid confusion with the
      management operation telnet, NETCONF, console, etc.

      transaction Id: If available, this message field contains in syslog)
   within a unique
      identifier for the associated management operation. NETCONF event notification.

B.1  Leveraging Syslog Field Definitions

   This is
      implementation dependent and may require additional information to
      be communicated section provides a semantic mapping between server NETCONF event fields
   and client.  A possible option is 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 )

B.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 make use of the message-id in the NETCONF rpc header

B.3.3  Data Source

   The data source Event field mapping

   Notes:

   VERSION:  Schema version is used, for example, found in the copy configuration
   command XML Schema namespace.  However,
   no correspondence to indicated the source of information 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 the copy
   operation

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

B.3.4  Operation

   Operation syslog ID 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.

   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 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 configuration prior to the execution contents of the entered command.

   Applicable Event Classes: configuration

B.3.9  Non-netconf commands this field may be included 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 AdditionalText
   field.

B.1.2  Severity Mapping

   The severity value mappings stated 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 (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 Perceived Severity to indicate
   whether this non-XML formatted information is of interest syslog SEVERITY mapping.

B.2  Syslog within NETCONF Events

B.2.1  Motivation

   The latter syslog protocol (RFC3164) is done widely used 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 equipment vendors as
   a means to issue the deliver 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 messages.  Due to be
   initiated by the NETCONF client.  With the introduction widespread use of event
   notifications in NETCONF
   syslog as well deployments which might require the
   "call-home" feature to get around firewall and/or NAT issues, the
   ability for as a NETCONF server to initiate sessions becomes important.

   Other potential uses phased availability and coverage of this feature includes the following
   deployment scenario: NE registration/auto-configuration.  The device
   NETCONF events by equipment vendors, it is pre-configured with envisioned that users will
   also follow a target destination address (the management
   station's address) where it needs phased migration.  As a way to register facilitate migration and download its
   configuration.  When managing large numbers of devices (e.g.  CPEs)
   this also allows for increased scalability since
   at the management
   station does not need to maintain established sessions to all managed
   devices.

   This appendix proposes extensions same time allow equipment vendors to the provide comprehensive
   event coverage over a NETCONF event subscription session
   establishment procedures and related operations to allow for server
   session initiation.

   Note that session, syslog
   messages could be embedded in their entirety within the security implications body of this approach, compared with
   more traditional, well understood models, is for further study. a
   NETCONF event notification.

   The subscription information as described provided 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 appendix describes additional functionality a mechanism to
   leverage syslog messages for persisting event
   subscription information and allowing the NETCONF server (e.g.
   network element) to initiate purpose of complementing the
   available NETCONF event subscription session.

   QUICK SUMMARY: notification set.  The <create-subscription>, <cancel-subscription>,
   <modify-subscription> operations would be used in same manner as
   described in doc.  It may intent is to promote
   the use useful of the NETCONF interface and not to allow simply provide a client wrapper
   and server to
   re-establish an additional delivery mechanism for syslog messages.  NETCONF
   events subscription.  This would result in another
   capability to allow session initiation by the server.

B.4.2  Establishment

   In order are intended to establish be well defined and structured, therefore
   providing an event subscription, a client must issue a
   <create-subscription> message request.  Upon a successful response
   from advantage over the server (e.g. network element) unstructured and often times
   arbitrarily defined syslog messages (i.e. the event subscription message field).

   Covered herein is
   established.  With this modified persistent version of the
   subscription, syslog protocol as defined in RFC3164 and
   draft-ietf-syslog-protocol-14.txt.

B.2.2  Embedding syslog messages in a NETCONF Event

   When event notifications are supported, the default behaviour for a
   NETCONF server would maintain the subscription
   information as part of its configuration.

B.4.3  Teardown

   A event subscription is torn down when a) to send NETCONF event notifications over an
   established event subscription.  As an option, the client issues NETCONF server may
   embed a
   <cancel-subscription> syslog message in its entirety (e.g.  RFC3164 - PRI, Header,
   and Message fields), placing it is successfully processed by
   the server (i.e. within the server issues Event Info field
   (SyslogInfo sub-field) - see Figure 1.

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

           Figure 1 - Embedding syslog in a positive response) or b) NETCONF Event Notifications

B.2.3  Supported Forwarding Options

   Three event forwarding options may be supported by the NETCONF session carrying
   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 subscription goes down notification
   messages defined for any
   reason.

   If use over the subscription NETCONF protocol.  While their use
   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 necessarily limited to re-establish the
   session by specifying the subscription Id.

B.4.4  Suspend And Resume

   Since NETCONF protocol, they are referred to
   as "NETCONF XML-event" in the purpose remainder of the <cancel-subscription> operation is this section simply to stop
   event notification forwarding
   avoid ambiguity.

B.2.3.1  XML and Syslog option - Forwarding Behaviour

   It is possible, due to its transient nature removes
   all subscription configuration; a different mechanism might be needed coverage, for shutting down the session but preserving the subscription
   information thus allowing the a given NETCONF server implementation
   to re-establish the
   parameters and reproduce the subscription.

   The suspend and resume commands would allows not support a comprehensive set of NETCONF client to
   suspend event notification forwarding without removing the existing
   subscription information.  Operations <suspend-subscription> and
   ><resume-subscription> are proposed notifications.
   Therefore, it is possible for this purpose.

   Since a given event subscription information is now persistent, unsolicited
   session termination (i.e. other than <cancel-subscription))  is
   treated as if to trigger the generation
   of a  <suspend-subscription>  command was issued.  Event
   forwarding is resumed by sending syslog message without a <resume-subscription> to NETCONF-aware counterpart.  In such
   situations, the NETCONF server on could form a new connection.

B.4.5  Lifecycle

   Configuration information associated with the NETCONF event subscription
   (event classes and  filters) could persist beyond
   notification, embed the life of syslog message in the
   event subscription session. (i.e. it is maintained by SyslogInfo field and
   forward the network
   element as part of its configuration).  This configuration
   information is subject NETCONF event notifications to the behaviour of the datastore it resides
   in all subscribed
   destinations.  Otherwise, both NETCONF event and may or may not persist across re-boots (e.g. it could syslog messages must
   be part
   of included in the running configuration but not Event Info field.

B.2.3.2  Event Class Identification

   The event class field is found in the startup configuration).

Appendix C. NETCONF Event Notifications and Syslog

   This appendix describes event header
   information as described in the main body of this document.  It
   conveys information describing what type of event for which 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 generated and lets the consumer of the appendix describes an optional capability to
   embed an entire syslog message (hereafter referred to as syslog
   message(s) know
   what sort of content to avoid confusion with the message field in syslog)
   within a expect.  NETCONF event notification.

C.1  Leveraging Syslog Field Definitions

   This section provides notifications which
   only contain 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 )

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 (Options c) must have the EventClass
   field set to "syslog".  The NETCONF Event field mapping

   Notes:

   VERSION:  Schema version is found client parses the message in XML Schema namespace.  However,
   no correspondence the
   same manner as any other message, finds the normal fields (ie, XML-
   marked content) not present and either proceeds to syslog.

   FACILITY: No well defined semantics parse the
   SyslogInfo field or hands the syslog message to the entity
   responsible for this field.  Therefore not
   used at this time.

   TRUNCATE: Not applicable. processing syslog messages.

B.2.3.3  Event Subscription Options

   A NETCONF events must be complete client may request subscription to options b) XML
   documents therefore cannot be truncated.

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

   PROC-ID: No equivalent field

   CONTENT: This to forward NETCONF XML only event
   notifications.  [Editor's Note: How is this done exactly?]

B.2.3.4  Supported Forwarding Option Discovery

   A potential means for a free form text field with NETCONF server to convey its feature set
   support is via capabilities.  However, in this particular case, the
   event content is not defined semantics.
   The contents a protocol feature therefore other means are
   needed.  A future version of this field may be included document will address this issue.

Appendix C.  Example Configuration Notifications

   This non-normative appendix provides a detailed description of a
   configuration change event notification definition in support of the AdditionalText
   field.

C.1.2  Severity Mapping

   The severity value mappings stated in (draft-ietf-syslog-protocol-14)
   configuration operations, particularly those defined by the NETCONF
   protocol.

C.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 used:

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

      Figure 5. ITU PerceivedSeverity reported regardless of
   what specific method was used to syslog SEVERITY mapping.

C.2  Syslog 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 Events

C.2.1  Motivation

   The syslog protocol (RFC3164) operations.  These include:

   o  copy-config event

      *  This is widely used by equipment vendors as a means to deliver data store level event messages.  Due to generated following the widespread use
         successful completion of
   syslog as well as a potential phased availability and coverage copy-config operation.  This
         represents the creation of
   NETCONF events by equipment vendors, it a new configuration file or
         replacement of an existing one.

   o  delete-config event

      *  This is envisioned that users will
   also follow a phased migration.  As data store level event generated following the
         successful completion of a way 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 facilitate migration and
   at the same time allow equipment vendors completion of
         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 provide comprehensive report completely unsuccessful configuration
         operations.

   o  lock-config event coverage over

      *  This is a NETCONF data store level event subscription session, syslog
   messages could be embedded in their entirety within generated following the body
         successful locking of a
   NETCONF configuration data store.

   o  unlock-config event notification.

   The information provided in this appendix describes

      *  This is a mechanism to
   leverage syslog messages for data store level event generated following the purpose
         successful release of complementing a lock previously held on a configuration
         data store.

C.2  Config Event Notification Structure

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

   Nomenclature:

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

   M - This 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 mandatory field that must 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 included.  Dependency on
   event class may exist as defined in RFC3164 and
   draft-ietf-syslog-protocol-14.txt.

C.2.2  Embedding syslog messages in a NETCONF noted below
    -----------------------------------------------------
              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
    -----------------------------------------------------

C.3  Configuration Event

   When Content

   The applicability of these fields to other event notifications are supported, the default behaviour for a
   NETCONF server classes is for
   further study.

C.3.1  Target Datastore

   Target datastore refers 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,
   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 data store (startup, candidate,
   running) which was modified by the NETCONF
   server: a) XML only (mandatory if NETCONF events capability management operation.

C.3.2  User Info

   This is
   supported) b) XML and syslog (Optional) c) syslog only (optional)

   Note used to convey information describing who originated the reader: Option "a" above refers to
   configuration event notification
   messages defined and the means for use over submitting the NETCONF protocol.  While their use
   is not necessarily limited to NETCONF protocol, they are referred request.  The
   user info field contains the following information:

      user Name: User id which was authorized to
   as "NETCONF XML-event" in execute the remainder associated
      management operation causing the generation of this section simply 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
   avoid ambiguity.

C.2.3.1  XML
      be communicated between server and Syslog client.  A possible option - Forwarding Behaviour

   It is possible, due to coverage, for a given NETCONF implementation
      to not support a comprehensive set make use of the message-id in the NETCONF event notifications.
   Therefore, it rpc header

C.3.3  Data Source

   The data source is possible used, for a given event example, in the copy configuration
   command to trigger indicated the generation source 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 information used in the SyslogInfo field and
   forward copy
   operation

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

C.3.4  Operation

   Operation is used, for example, in the NETCONF event notifications edit configuration command to all subscribed
   destinations.  Otherwise, both NETCONF event and syslog messages must
   be included in
   indicated the specific operation that has taken place - create,
   delete, merge, replace.

   Applicable Event Info field.

C.2.3.2 Classes: configuration (useful for edit-config)

C.3.5  Context

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

   Applicable Event Class Identification Classes: configuration

C.3.6  Entered Command

   The event class field is found command entered and executed on the device.

C.3.7  New Config

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

   Applicable Event Classes: configuration

C.3.8  Old Config

   The configuration prior to the execution of the entered command.

   Applicable Event Classes: configuration

C.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 NETCONF event header information as described in the main body of this document.  It
   conveys information describing message needs to be clearly tagged so that type of event for which the event
   notification is generated and lets the
   consumer of the message know information knows what to expect.  NETCONF event notifications which only contain a
   syslog message (Options b or c) must have  In addition, the EventClass field set to
   "information".  [Editor's Note: This
   creation of the subscription needs to be thought through.  It
   may not be allow for 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 indicate
   whether this non-XML formatted information is of interest

   The latter is done by identifying the syslog message to XML namespace under which the entity
   responsible for processing syslog messages.

C.2.3.3  Event Subscription Options
   data syntax/schema is defined.  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 requests the user-specified filter.  The FILTER or NAMED
   FILTER parameter format
   in <create-subscription>.  As previously indicated, which it wants 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, issue the event content notifications
   at subscription time by specifying the appropriate namespace under
   the Filter parameter in the  <create-subscription>  operation.  An
   example is not a protocol feature therefore other means are
   needed.  A future version of this document will address this issue. provided below:

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

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