Network Working Group                                    R. Enns, Editor
Internet-Draft                                          Juniper Networks
Expires: December 18, 2004                                 June 19, 2004


                     NETCONF Configuration Protocol
                       draft-ietf-netconf-prot-03

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
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   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on December 18, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   The NETCONF configuration protocol defined in this document provides
   mechanisms to install, manipulate, and delete the configuration of
   network devices.  It uses an XML-based data encoding for the
   configuration data as well as the protocol messages.  The NETCONF
   protocol operations are realized on top of a simple RPC layer.

   Please send comments to netconf@ops.ietf.org.  To subscribe, use
   netconf-request@ops.ietf.org.







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Table of Contents

   1.    Introduction . . . . . . . . . . . . . . . . . . . . . . . .  5
   1.1   Protocol Overview  . . . . . . . . . . . . . . . . . . . . .  6
   1.2   Capabilities . . . . . . . . . . . . . . . . . . . . . . . .  7
   1.3   Separation of Configuration and State Data . . . . . . . . .  7
   2.    Application Protocol Requirements  . . . . . . . . . . . . .  9
   2.1   Connection-oriented operation  . . . . . . . . . . . . . . .  9
   2.2   Security and Privacy . . . . . . . . . . . . . . . . . . . .  9
   2.3   Authentication . . . . . . . . . . . . . . . . . . . . . . . 10
   3.    RPC Model  . . . . . . . . . . . . . . . . . . . . . . . . . 11
   3.1   Namespace  . . . . . . . . . . . . . . . . . . . . . . . . . 11
   3.2   <rpc> Element  . . . . . . . . . . . . . . . . . . . . . . . 11
   3.3   <rpc-reply> Element  . . . . . . . . . . . . . . . . . . . . 12
   3.4   <rpc-error> Element  . . . . . . . . . . . . . . . . . . . . 12
   3.5   <ok> Element . . . . . . . . . . . . . . . . . . . . . . . . 14
   3.6   Pipelining . . . . . . . . . . . . . . . . . . . . . . . . . 14
   4.    Configuration Model  . . . . . . . . . . . . . . . . . . . . 15
   4.1   Configuration Datastores . . . . . . . . . . . . . . . . . . 15
   5.    Protocol Operations  . . . . . . . . . . . . . . . . . . . . 16
   5.1   <get-config> . . . . . . . . . . . . . . . . . . . . . . . . 16
   5.2   <edit-config>  . . . . . . . . . . . . . . . . . . . . . . . 19
   5.3   <copy-config>  . . . . . . . . . . . . . . . . . . . . . . . 24
   5.4   <delete-config>  . . . . . . . . . . . . . . . . . . . . . . 25
   5.5   <lock> . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
   5.6   <unlock> . . . . . . . . . . . . . . . . . . . . . . . . . . 28
   5.7   <get>  . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
   5.8   <close-session>  . . . . . . . . . . . . . . . . . . . . . . 31
   5.9   <kill-session> . . . . . . . . . . . . . . . . . . . . . . . 31
   6.    Capabilities . . . . . . . . . . . . . . . . . . . . . . . . 33
   6.1   Capabilities Exchange  . . . . . . . . . . . . . . . . . . . 33
   6.2   Writable-Running Capability  . . . . . . . . . . . . . . . . 34
   6.2.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 34
   6.2.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 34
   6.2.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 34
   6.2.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 34
   6.2.5 Modifications to Existing Operations . . . . . . . . . . . . 34
   6.3   Candidate Configuration Capability . . . . . . . . . . . . . 35
   6.3.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 35
   6.3.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 35
   6.3.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 35
   6.3.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 36
   6.3.5 Modifications to Existing Operations . . . . . . . . . . . . 37
   6.4   Confirmed Commit Capability  . . . . . . . . . . . . . . . . 38
   6.4.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 38
   6.4.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 38
   6.4.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 38
   6.4.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 39



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   6.4.5 Modifications to Existing Operations . . . . . . . . . . . . 39
   6.5   Rollback on Error Capability . . . . . . . . . . . . . . . . 39
   6.5.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 39
   6.5.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 40
   6.5.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 40
   6.5.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 40
   6.5.5 Modifications to Existing Operations . . . . . . . . . . . . 40
   6.6   Validate Capability  . . . . . . . . . . . . . . . . . . . . 41
   6.6.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 41
   6.6.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 41
   6.6.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 41
   6.6.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 41
   6.7   Distinct Startup Capability  . . . . . . . . . . . . . . . . 42
   6.7.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 42
   6.7.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 42
   6.7.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 42
   6.7.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 43
   6.7.5 Modifications to Existing Operations . . . . . . . . . . . . 43
   6.8   URL Capability . . . . . . . . . . . . . . . . . . . . . . . 43
   6.8.1 Description  . . . . . . . . . . . . . . . . . . . . . . . . 43
   6.8.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 43
   6.8.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 43
   6.8.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 44
   6.8.5 Modifications to Existing Operations . . . . . . . . . . . . 44
   7.    XML Usage Guidelines for NETCONF . . . . . . . . . . . . . . 45
   7.1   No DTDs  . . . . . . . . . . . . . . . . . . . . . . . . . . 45
   7.2   Avoid Mixed Content  . . . . . . . . . . . . . . . . . . . . 45
   7.3   Use an Explicit Namespace on Attributes  . . . . . . . . . . 45
   7.4   Use Container Elements for Lists . . . . . . . . . . . . . . 46
   7.5   Elements and Attributes  . . . . . . . . . . . . . . . . . . 46
   7.5.1 Consider Attributes as Metadata  . . . . . . . . . . . . . . 46
   7.5.2 Consider the Lack of Extensibility of Attributes . . . . . . 46
   7.6   Proper Tag Names . . . . . . . . . . . . . . . . . . . . . . 46
   8.    Security Considerations  . . . . . . . . . . . . . . . . . . 48
   9.    IANA Considerations  . . . . . . . . . . . . . . . . . . . . 49
   10.   Authors and Acknowledgements . . . . . . . . . . . . . . . . 50
         Normative References . . . . . . . . . . . . . . . . . . . . 51
         Informative References . . . . . . . . . . . . . . . . . . . 52
         Author's Address . . . . . . . . . . . . . . . . . . . . . . 52
   A.    NETCONF Error List . . . . . . . . . . . . . . . . . . . . . 53
   B.    XML Schema for NETCONF RPC and Protocol Operations . . . . . 57
   C.    XML Schema for NETCONF State Data  . . . . . . . . . . . . . 63
   D.    Capability Template  . . . . . . . . . . . . . . . . . . . . 66
   D.1   capability-name (template) . . . . . . . . . . . . . . . . . 66
   D.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 66
   D.1.2 Dependencies . . . . . . . . . . . . . . . . . . . . . . . . 66
   D.1.3 Capability and Namespace . . . . . . . . . . . . . . . . . . 66
   D.1.4 New Operations . . . . . . . . . . . . . . . . . . . . . . . 66



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   D.1.5 Modifications to Existing Operations . . . . . . . . . . . . 66
   D.1.6 Interactions with Other Capabilities . . . . . . . . . . . . 66
   E.    Configuring Multiple Devices with NETCONF  . . . . . . . . . 67
   E.1   Operations on Individual Devices . . . . . . . . . . . . . . 67
   E.1.1 Acquiring the Configuration Lock . . . . . . . . . . . . . . 67
   E.1.2 Loading the Update . . . . . . . . . . . . . . . . . . . . . 68
   E.1.3 Validating the Incoming Configuration  . . . . . . . . . . . 68
   E.1.4 Checkpointing the Running Configuration  . . . . . . . . . . 69
   E.1.5 Changing the Running Configuration . . . . . . . . . . . . . 70
   E.1.6 Testing the New Configuration  . . . . . . . . . . . . . . . 70
   E.1.7 Making the Change Permanent  . . . . . . . . . . . . . . . . 71
   E.1.8 Releasing the Configuration Lock . . . . . . . . . . . . . . 71
   E.2   Operations on Multiple Devices . . . . . . . . . . . . . . . 71
   F.    Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 73
   F.1   draft-ietf-netconf-prot-03 . . . . . . . . . . . . . . . . . 73
   F.2   draft-ietf-netconf-prot-02 . . . . . . . . . . . . . . . . . 74
         Intellectual Property and Copyright Statements . . . . . . . 76


































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1. Introduction

   The NETCONF protocol defines a simple mechanism through which a
   network device can be managed, configuration data and system state
   information can be retrieved, and new configuration data can be
   uploaded and manipulated.  The protocol allows the device to expose a
   full, formal, application programming interface (API).  Applications
   can use this straight-forward API to send and receive full and
   partial configuration data sets.

   NETCONF uses a remote procedure call (RPC) paradigm to define a
   formal API for the network device.  A client encodes an RPC in XML
   [1] and sends it to a server using a secure, connection-oriented
   session.  The server responds with a reply encoded in XML.  The
   contents of both the request and the response are fully described in
   XML DTDs or XML schemas, or both, allowing both parties to recognize
   the syntax constraints imposed on the exchange.

   A key aspect of NETCONF is that it allows the functionality of the
   API to closely mirror the native functionality of the device.  This
   reduces implementation costs and allows timely access to new
   features.  In addition, applications can access both the syntactic
   and semantic content of the device's native user interface.

   NETCONF allows a client to discover the set of protocol extensions
   supported by the server.  These "capabilities" permit the client to
   adjust its behavior to take advantage of the features exposed by the
   device.  The capability definitions can be easily extended in a
   noncentralized manner.  Standard and vendor-specific capabilities can
   be defined with semantic and syntactic rigor.  Capabilities are
   discussed in Section 6.

   The NETCONF protocol is a building block in a system of automated
   configuration.  XML is the lingua franca of interchange, providing a
   flexible but fully specified encoding mechanism for hierarchical
   content.  NETCONF can be used in concert with XML-based
   transformation technologies such as XSLT to provide a system for
   automated generation of full and partial configurations.  The system
   can query one or more databases for data about networking topologies,
   links, policies, customers, and services.  This data can be
   transformed using one or more XSLT [7] scripts from a
   vendor-independent data schema into a form that is specific to the
   vendor, product, operating system, and software release.  The
   resulting data can be passed to the device using the NETCONF
   protocol.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this



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   document are to be interpreted as described in RFC 2119 [2].

1.1 Protocol Overview

   NETCONF uses a simple RPC-based mechanism to facilitate communication
   between a client and a server.  The client is a script or application
   typically running as part of a network manager.  The server is a
   network device.  The terms "device" and "server" are used
   interchangeably in this document, as are "client" and "application".

   A NETCONF session is the logical connection between a network
   administrator or network configuration application and a network
   device.  A device MUST support at least one NETCONF session, and MAY
   support more than one.  Global configuration attributes can be
   changed during any session, and the affects are visible in all
   sessions.  Session-specific attributes affect only the session in
   which they are changed.

   NETCONF can be conceptually partitioned into four layers:

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

   1.  The application protocol layer provides a communication path
       between the client and server.  NETCONF can be layered over any
       application protocol that provides a set of basic requirements.
       Section 2 discusses these requirements.

   2.  The RPC layer provides a simple, transport-independent framing
       mechanism for encoding RPCs.  Section 3 documents this protocol.

   3.  The operations layer defines a set of base operations invoked as
       RPC methods with XML-encoded parameters.  Section 5 details the



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       list of base operations.

   4.  The content layer is outside the scope of this document.  Given
       the current proprietary nature of the configuration data being
       manipulated, the specification of this content depends on the
       device vendor.  It is expected that a separate effort to specify
       a standard data definition language and standard content will be
       undertaken.


1.2 Capabilities

   A NETCONF capability is a set of  functionality that supplements the
   base NETCONF specification.  The capability is identified by a
   uniform resource identifier (URI).  These URIs should follow the
   guidelines as described in Section 6.

   Capabilities augment the base operations of the device, describing
   both additional operations and the content allowed inside operations.
   The client can discover the server's capabilities and use any
   additional operations, parameters, and content defined by those
   capabilities.

   The capability definition may name one or more dependent
   capabilities.  These capabilities must be implemented before the
   first capability can function properly.  To support a capability, the
   server MUST support any capabilities upon which it depends.

   Section 6 defines the capabilities exchange that allows the client to
   discover the server's capabilities.  Section 6 also lists the set of
   capabilities defined in this document.

   Additional capabilities can be defined at any time in external
   documents, allowing the set of capabilities to expand over time.
   Standards bodies may define standardized capabilities and vendors may
   define proprietary ones.  The capability URI MUST sufficiently
   distinguish the naming authority to avoid naming collisions.

1.3 Separation of Configuration and State Data

   The information that can be retrieved from a running system is
   separated into two classes, configuration data and state data.
   Configuration data is the set of writable data that is required to
   transform a system from its initial default state into its current
   state.  State data is the additional data on a system that is not
   configuration data such as read-only status information and collected
   statistics.  When a device is performing configuration operations a
   number of problems would arise if state data were included:



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   o  Comparisons of configuration files would be dominated by
      irrelevant entries such as different statistics.

   o  A command to load the file would contain nonsensical commands such
      as commands to write read-only data.

   o  The configuration file would be too large.

   To account for these issues, the NETCONF protocol recognizes the
   difference between configuration data and state data and provides
   commands that operate on each independently.  The <get-config>
   command retrieves configuration data only while the <get> command
   retrieves configuration and state data.

   Note that the NETCONF protocol is concerned only with information
   required to get the system software into its desired running state.
   Other important persistent data such as user files and databases are
   not treated as configuration data by the NETCONF protocol.
   Similarly, the collection of configuration files stored on a system
   (for example, the configuration files themselves) is not itself
   included in configuration data.

   If a local database of user authentication data is stored on the
   device, whether it is included in configuration data is an
   implementation dependent matter.


























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2. Application Protocol Requirements

   NETCONF uses an RPC-based communication paradigm.  A client sends a
   series of one or more RPC request operations, which cause the server
   to respond with a corresponding series of RPC replies.

   The NETCONF protocol can be layered on any application protocol that
   provides the required set of functionality.  It is not bound to any
   particular application protocol, but allows a mapping to define how
   it can be implemented over any specific protocol.

   The application protocol MUST provide a mechanism to indicate the
   session type (manager or agent) to the NETCONF protocol layer.

   This section details the characteristics that NETCONF requires from
   the underlying application protocol.

2.1 Connection-oriented operation

   NETCONF is connection-oriented, requiring a persistent connection
   between peers.  This connection must provide reliable, sequenced data
   delivery.

   NETCONF connections are long-lived, persisting between protocol
   operations.  This allows the client to make changes to the state of
   the connection that will persist for the lifetime of the connection.
   For example, authentication information specified for a connection
   remains in effect until the connection is closed.

   In addition, resources requested from the server for a particular
   connection MUST be automatically released when the connection closes,
   making failure recovery simpler and more robust.  For example, when a
   lock is acquired by a peer, the lock persists until either explicitly
   released or the server determines that the connection has been
   terminated.  If a connection is terminated while the client holds a
   lock, the server can perform any appropriate recovery.  The lock
   operation is further discussed in Section 5.5

2.2 Security and Privacy

   NETCONF connections must provide authentication, data integrity, and
   privacy.  NETCONF depends on the application protocol for this
   capability.  A NETCONF peer assumes that an appropriate level of
   security and privacy are provided independent of this document.  For
   example, connections may be encrypted in TLS [4] or SSH [11],
   depending on the underlying protocol.





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2.3 Authentication

   NETCONF connections must be authenticated.  The application protocol
   is responsible for authentication.  The peer assumes that the
   connection's authentication information has been validated by the
   underlying protocol using sufficiently trustworthy mechanisms and
   that the peer's entity can be trusted.

   One goal of NETCONF is to provide a programmatic interface to the
   device that closely follows the functionality of the device's native
   interface.  Therefore, it is expected that the underlying protocol
   uses existing authentication mechanisms defined by the device.  For
   example, a device that supports RADIUS [5] should use RADIUS to
   authenticate NETCONF sessions.

   The authentication process should result in an entity whose
   permissions and capabilities are known to the device.  These
   permissions must be enforced during the NETCONF session.  For
   example, if the native user interface restricts users from changing
   the network interface configuration, the user should not be able to
   change this configuration data using NETCONF.






























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3. RPC Model

   The NETCONF protocol uses an RPC-based communication model.  NETCONF
   peers use <rpc> and <rpc-reply> elements to provide application
   protocol-independent framing of NETCONF requests and responses.

3.1 Namespace

   The <rpc> and <rpc-reply> elements are defined in the following
   namespace:

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


3.2 <rpc> Element

   The <rpc> element is used to enclose a NETCONF request sent from the
   manager to the agent.

   The <rpc> element has a mandatory attribute "message-id", which is an
   arbitrary string chosen by the sender of the RPC that will commonly
   encode a monotonically increasing integer.  The receiver of the RPC
   does not decode or interpret this string but simply saves it to use
   as a "message-id" attribute in any resulting <rpc-reply> message.
   For example:

       <rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <some-method>
           ...
         </some-method>
       </rpc>

   If additional attributes are present in an <rpc> element, a NETCONF
   peer must return them unmodified in the <rpc-reply> element.

   The name and parameters of an RPC are encoded as the contents of the
   <rpc> element.  The name of the RPC is an element directly inside the
   <rpc> element, and any parameters are encoded inside this element.

   The following example invokes a method called "my-own-method" which
   has two parameters, "my-first-parameter", with a value of "14", and
   "another-parameter", with a value of "fred":

     <rpc message-id="102" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <my-own-method xmlns="http://example.net/me/my-own/1.0">
         <my-first-parameter>14</my-first-parameter>
         <another-parameter>fred</another-parameter>
       </my-own-method>



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     </rpc>

   The following example invokes a "rock-the-house" method with a
   "zip-code" parameter of "27606-0100":

     <rpc message-id="103" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <rock-the-house xmlns="http://example.net/house/rock/1.0">
         <zip-code>27606-0100</zip-code>
       </rock-the-house>
     </rpc>

   The following example invokes the "rock-the-world" method with no
   parameters:

     <rpc message-id="104" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <rock-the-world xmlns="http://example.net/house/rock/1.0"/>
     </rpc>


3.3 <rpc-reply> Element

   The <rpc-reply> message is sent in response to a <rpc> operation.

   The <rpc-reply> element has a mandatory attribute "message-id", which
   is equal to the "message-id" attribute of the <rpc> for which this is
   a response.

   A NETCONF peer must also return any additional attributes included in
   the <rpc> element unmodified in the <rpc-reply> element.

   The response name and response data are encoded as the contents of
   the <rpc-reply> element.  The name of the reply is an element
   directly inside the <rpc-reply> element, and any data is encoded
   inside this element.

   For example:

       <rpc-reply message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <some-content>
           ...
         </some-content>
       </rpc-reply>


3.4 <rpc-error> Element

   The <rpc-error> element is sent in <rpc-reply> messages if an error
   occurs during the processing of an <rpc> request.



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   The <rpc-error> element includes the following information:

   error-type: Defines the conceptual layer that the error occurred.
      Enumeration.  One of:

      *  transport

      *  rpc

      *  protocol

      *  application

   error-tag: String identifying the error condition.  See list below
      for allowed values.

   error-severity: String identifying the error severity, as determined
      by the device.  One of:

      *  error

      *  warning

   error-app-tag: String identifying the data model specific or vendor
      specific error condition, if one exists.  This element will not be
      present if no appropriate application error tag can be associated
      with a particular error condition.

   error-path: Absolute XPATH expression identifying the element path to
      the node which is associated with the error being reported in a
      particular rpc-error element.  This element will not be present if
      no appropriate payload element can be associated with a particular
      error condition, or if the 'bad-element' QString returned in the
      'error-info' container is sufficient to identify the node
      associated with the error.

   error-message: String describing the error condition.  This element
      will not be present if no appropriate message is provided for a
      particular error condition.

   error-info: Contains protocol or data model specific error content.
      This element will not be present if no such error content is
      provided for a particular error condition.  The list below defines
      any mandatory error-info content for each error.  After any
      protocol-mandated content, a data model definition may mandate
      certain application layer error information be included in the
      error-info container.  A vendor may include additional elements at
      the end of the sequence to provide extended and/or



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      implementation-specific debugging information.

   Appendix A enumerates the standard NETCONF errors.

   Example: An <rpc> element is received without a message-id attribute.

     <rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <get-config>
         <source>
           <running/>
         </source>
       </get-config>
     </rpc>

     <rpc-reply message-id="102" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <rpc-error>
         <error-type>rpc</error-type>
         <error-tag>MISSING_ATTRIBUTE</error-tag>
         <error-severity>error</error-severity>
         <error-info>
           <bad-attribute>message-id</bad-attribute>
           <bad-element>rpc</bad-element>
         </error-info>
       </rpc-error>
     </rpc-reply>


3.5 <ok> Element

   The <ok> element is sent in <rpc-reply> messages if no error occurred
   during the processing of an <rpc> request.  For example:

     <rpc-reply message-id="102" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <ok/>
     </rpc-reply>


3.6 Pipelining

   NETCONF <rpc> requests are processed serially by the managed device.
   Additional <rpc> requests MAY be sent before previous ones have been
   completed.  The managed device MUST send responses only in the order
   the requests were received.








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4. Configuration Model

   NETCONF provides an initial set of operations and a number of
   capabilities that can be used to extend the base.  NETCONF peers
   exchange device capabilities when the session is initiated as
   described in Section 6.1.

4.1 Configuration Datastores

   NETCONF defines the existence of one or more configuration datastores
   and allows configuration operations on them.  A configuration
   datastore is defined as the complete set of configuration data that
   is required to get a device from its initial default state into a
   desired operational state.  The configuration datastore does not
   include state data or executive commands.

   Only the <running> configuration datastore is present in the base
   model.  Additional configuration datastores may be defined by
   capabilities.  Such configuration datastores are available only on
   devices that advertise the capabilities.

   o  Running: The complete configuration currently active on the
      network device.  Only one configuration datastore of this type
      exists on the device, and it is always present.  NETCONF protocol
      operations refer to this datastore using the <running> element.

   Section 6.3 and Section 6.7 define the <candidate> and <startup>
   configuration datatores, respectively.























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5. Protocol Operations

   The NETCONF protocol provides a small set of low-level operations to
   manage device configurations and retrieve device state information.
   The base protocol provides operations to retrieve, configure, copy,
   and delete configuration datastores.  Additional operations are
   provided, based on the capabilities advertised by the device.

   The base protocol includes the following protocol operations:

   o  get-config

   o  edit-config

   o  copy-config

   o  delete-config

   o  lock

   o  unlock

   o  get

   o  close-session

   o  kill-session

   A protocol operation may fail for various reasons, including
   "operation not supported".  An initiator should not assume that any
   operation will always succeed.  The return values in any RPC reply
   should be checked for error responses.

   The syntax and XML encoding of the protocol operations are formally
   defined in the XML schema in Appendix B.  The following sections
   describe the semantics of each protocol operation.

5.1 <get-config>

   Description:

      Retrieve all or part of a specified configuration.

   Parameters:

      source:





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         Name of the configuration datastore being queried, such as
         <running>.

      filter:

         The filter element identifies the portions of the device
         configuration to retrieve.  If this parameter is empty or
         unspecified, the entire configuration is returned.

         [ed.  May allow for different types of filters via a
         filter-type attribute.  If so, must indicate which is mandatory
         to implement.]

   Positive Response:

      If the device can satisfy the request, the server sends an
      <rpc-reply> element containing a <config> element with the results
      of the query.

   Negative Response:

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

   Example:


























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       <rpc message-id="105" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <get-config>
           <source>
             <running/>
           </source>
           <filter>
             <config xmlns="http://example.com/schema/1.2/config">
               <users/>
             </config>
           </filter>
         </get-config>
       </rpc>

       <rpc-reply message-id="105" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <config xmlns="http://example.com/schema/1.2/config">
           <users>
             <user>
               <name>root</name>
               <type>superuser</type>
               <full-name>Charlie Root</full-name>
             </user>
             <user>
               <name>fred</name>
               <type>admin</type>
               <full-name>Fred Flintstone</full-name>
             </user>
             <user>
               <name>barney</name>
               <type>admin</type>
               <full-name>Barney Rubble</full-name>
             </user>
           </users>
         </config>
       </rpc-reply>

       The following example shows how additional nesting within the
      <config> parameter can be used to filter more of the output in the
      response:













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       <rpc message-id="106" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <get-config>
           <source>
             <running/>
           </source>
           <filter>
             <config xmlns="http://example.com/schema/1.2/config">
               <users>
                 <user>
                   <name>fred</name>
                 </user>
               </users>
             </config>
           </filter>
         </get-config>
       </rpc>

       <rpc-reply message-id="106" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <config xmlns="http://example.com/schema/1.2/config">
           <users>
             <user>
               <name>fred</name>
               <type>admin</type>
               <full-name>Fred Flintstone</full-name>
            </user>
           </users>
         </config>
       </rpc-reply>


5.2 <edit-config>

   Description:

      Load all or part of a specified configuration to the specified
      target configuration.  This operation allows the new configuration
      to be expressed in several ways, such as using a local file, a
      remote file, or inline.  If the target configuration does not
      exist, it is created.

      The device analyzes the source and target configurations and
      performs the requested changes.  The target configuration is not
      simply replaced, as with the <copy-config> message.

   Attributes:






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      operation:

         Elements in the <config> subtree may contain an operation
         attribute.  The attribute identifies the point in the
         configuration to perform the operation.

         In the interest of simplicity, all operation attributes
         appearing within the <config> subtree MUST have the same value.

         If the operation attribute is not specified, the configuration
         is merged into the configuration datastore.

         The operation attribute has one of the following values:

         merge: The configuration data identified by the element
            containing this attribute is merged with the configuration
            at the corresponding level in the configuration datastore
            identified by the target parameter.

         replace: The configuration data identified by the element
            containing this attribute replaces any related configuration
            in the configuration datastore identified by the target
            parameter.  Unlike a <copy-config> operation, which replaces
            the entire target configuration, only the configuration
            actually present in the config parameter is affected.

         create: The configuration data identified by the element
            containing this attribute is added to the configuration if
            and only if the configuration data does not already exist on
            the device.  If the configuration data exists, an
            <rpc-error> element is returned with an <error-tag> value of
            DATA_EXISTS.

         delete: The configuration data identified by the element
            containing this attribute is deleted in the configuration
            datastore identified by the target parameter.

   Parameters:

      target:

         Configuration datastore being edited, such as <running/>.

      test-option:

         The test-option element may be specified only if the device
         advertises the #validate capability (Section 6.6).




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         The test-option element has one of the following values:

         test-then-set: Perform a validation test before attempting to
            set.  If validation errors occur, do not perform the
            <edit-config> operation.  This is the default test-option.

         set: Perform a set without a validation test first.

      error-option:

         The error-option element has one of the following values:

         stop-on-error: Abort the edit-config operation on first error.
            This is the default error-option.

         ignore-error: Continue to process configuration data on error;
            error is recorded and negative response is generated if any
            errors occur.

         rollback-on-error: If an error condition occurs such that an
            error severity <rpc-error> element is generated, the agent
            will stop processing the edit-config operation and restore
            the specified configuration to its complete state at the
            start of this edit-config operation.  This option requires
            the agent to support the #rollback-on-error capability
            described in Section 6.5.

      config:

         Portion of the configuration subtree to edit.  The namespace of
         this configuration should be specified as an attribute of this
         parameter.

   Positive Response:

      If the device was able to satisfy the request, an <rpc-reply> is
      sent containing an <ok> element.

   Negative Response:

      An <rpc-error> response is sent if the request cannot be completed
      for any reason.

   Example: Set the MTU to 1500 on an interface named "Ethernet0/0" in
      the running configuration:






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       <rpc message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <edit-config>
           <target>
             <running/>
           </target>
           <config xmlns="http://example.com/schema/1.2/config">
             <interface>
               <name>Ethernet0/0</name>
               <mtu>1500</mtu>
             </interface>
           </config>
         </edit-config>
       </rpc>

       <rpc-reply message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>

      Add an interface named "Ethernet0/0" to the running configuration,
      replacing any previous interface with that name:

       <rpc message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <edit-config>
           <target>
             <running/>
           </target>
           <config xmlns="http://example.com/schema/1.2/config"
                   xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
             <interface xc:operation="replace">
               <name>Ethernet0/0</name>
               <mtu>1500</mtu>
               <address>
                 <name>1.2.3.4</name>
                 <mask>255.0.0.0</mask>
               </address>
             </interface>
           </config>
         </edit-config>
       </rpc>

       <rpc-reply message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>

      Delete the interface named "Ethernet0/0" from the running
      configuration:





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       <rpc message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <edit-config>
           <target>
             <running/>
           </target>
           <config xmlns="http://example.com/schema/1.2/config"
                   xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
             <interface xc:operation="delete">
               <name>Ethernet0/0</name>
             </interface>
           </config>
         </edit-config>
       </rpc>

       <rpc-reply message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>

      Delete interface 192.168.0.1 from an OSPF area (other interfaces
      configured in the same area are unaffected):

       <rpc message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <edit-config>
           <target>
             <running/>
           </target>
           <config xmlns="http://example.com/schema/1.2/config"
                   xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
             <protocols>
               <ospf>
                 <area>
                   <name>0.0.0.0</name>
                   <interfaces>
                     <interface xc:operation="delete">
                       <name>192.168.0.1</name>
                     </interface>
                   </interfaces>
                 </area>
               </ospf>
             </protocols>
           </config>
         </edit-config>
       </rpc>

       <rpc-reply message-id="107" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>




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5.3 <copy-config>

   Description:

      Create or replace an entire configuration datastore with the
      contents of another complete configuration datastore.  If the
      target datastore exists, it is overwritten.  Otherwise, a new one
      is created.

      A device may choose not to support the <running> configuration
      datastore as the <target> parameter of a <copy-config> operation.
      A device may choose not to support remote to remote copy
      operations.  The source and target parameters cannot identify the
      same file or configuration datastore.

   Parameters:

      source:

         The configuration datastore to use as the source of the copy
         operation or the <config> element containing the configuration
         subtree to copy.

      target:

         The configuration datastore to use as the destination of the
         copy operation.

   Positive Response:

      If the device 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.

   Example:












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       <rpc message-id="108" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <copy-config>
           <source>
             <running/>
           </source>
           <target>
             <url>ftp://example.com/configs/testbed-dec10.txt</url>
           </target>
         </copy-config>
       </rpc>

       <rpc-reply message-id="108" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>


5.4 <delete-config>

   Description:

      Delete a configuration datastore.  The <running> configuration
      file cannot be deleted.

   Parameters:

      target:

         Name of the configuration datastore to delete.

   Positive Response:

      If the device 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.

   Example:











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       <rpc message-id="108" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <delete-config>
           <target>
             <startup/>
           </target>
         </delete-config>
       </rpc>

       <rpc-reply message-id="108" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>


5.5 <lock>

   Description:

      The lock operation allows the client to lock the configuration
      system of a device.  Such locks are intended to be short-lived and
      allow a client to make a change without fear of interaction with
      other NETCONF clients, non-NETCONF clients (SNMP and Expect
      scripts) and human users.

      An attempt to lock the configuration MUST fail if an existing
      session or other entity holds a lock on any portion of the lock
      target.

      When the lock is acquired, the server MUST prevent any changes to
      the locked resource other than those requested by this session.
      SNMP and CLI requests to modify the resource MUST fail with an
      appropriate error.

      The duration of the lock is defined as beginning when the lock is
      acquired and lasting until either the lock is released or the
      NETCONF session closes.  The session closure may be explicitly
      performed by the client, or implicitly performed by the server
      based on criteria such as lack of network connectivity, failure of
      the underlying transport, or simple inactivity timeout.  This
      criteria is dependent on the vendor's implementation and the
      underlying transport.

      The lock operation takes an OPTIONAL parameter, target.  If the
      target parameter is specified, it names the configuration that
      will be locked.  If the target parameter is not specified, then by
      default the running configuration datastore will be locked.  When
      a lock is active, using the <edit-config> operation on the locked
      configuration and using the locked configuration as a target of
      the <copy-config> operation will be disallowed by any other



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      session.  Additionally, the system will ensure that these locked
      configuration resources will not be modified by other non-NETCONF
      management operations such as SNMP and CLI.  The <kill-session>
      message (at the RPC layer) can be used to force the release of a
      lock owned by another NETCONF session.  It is beyond the scope of
      this document to define how to break locks held by other entities.

      A lock will not be granted if any of the following conditions are
      true:

      *  a lock is already held by another NETCONF session or another
         entity

      *  the target configuration has already been modified and these
         changes have not been committed

      *  lock capability not supported

      The server MUST respond with either an <ok> element or an
      <rpc-error>.

      A lock will be released by the system if the session holding the
      lock is terminated for any reason.

   Parameters:

      target:

         Name of the configuration datastore to lock.  If this parameter
         is not present, then by default the running configuration
         datastore will be locked.

   Positive Response:

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

   Negative Response:

      An <rpc-error> element is included in the <rpc-reply> if the
      request cannot be completed for any reason.  This error response
      will include the session-id of the lock owner if the lock is
      already held.  If the lock is held by a non-NETCONF entity, a
      session-id of 0 (zero) is included.  Note that any other entity
      performing a lock on even a partial piece of a target will prevent
      a NETCONF lock (which is global) from being obtained on that
      target.




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   Example:

       <rpc message-id="120" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <lock>
           <target>
             <running/>
           </target>
         </lock>
       </rpc>

       <rpc-reply message-id="120" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/> <!-- lock succeeded -->
       </rpc-reply>

       <rpc message-id="121" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <lock>
           <target>
             <running/>
           </target>
         </lock>
       </rpc>

       <rpc-reply message-id="121" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <rpc-error> <!-- lock failed -->
           <error-type>protocol</error-type>
           <error-tag>LOCK_DENIED</error-tag>
           <error-severity>error</error-severity>
           <session-id>150</session-id>
           <error-message>Lock failed, lock is already held</error-message>
           <error-info>
             <session-id>454</session-id> <!-- lock is held by NETCONF session 454 -->
           </error-info>
         </rpc-error>
       </rpc-reply>


5.6 <unlock>

   Description:

      The unlock operation is used to release a configuration lock,
      previously obtained with the <lock> operation.

      An unlock operation will not succeed if any of the following
      conditions are true:

      *  the specified lock is not currently active




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      *  the session issuing the <unlock> operation is not the same
         session that obtained the lock

      The server MUST respond with either an <ok> element or an
      <rpc-error>.

   Parameters:

      target:

         Name of the configuration datastore to unlock.  If this
         parameter is not present, then by default the running
         configuration datastore will be unlocked.

         A NETCONF client is not permitted to unlock a configuration
         datastore that it did not lock.

   Positive Response:

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

   Negative Response:

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

   Example:

       <rpc message-id="121" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <unlock>
           <target>
            <running/>
           </target>
         </unlock>
       </rpc>

       <rpc-reply message-id="121" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>


5.7 <get>

   Description:






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      Retrieve configuration and device state information.  Appendix C
      describes the XML schema for NETCONF state data.

   Parameters:

      filter:

         This parameter specifies the portion of the system
         configuration and state data to retrieve.  If this parameter is
         empty, all the device configuration and state information is
         returned.

   Positive Response:

      If the device was able to satisfy the request, an <rpc-reply> is
      sent.  The <data> section contains the appropriate subset.

   Negative Response:

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

   Example:

       <rpc message-id="109" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <get>
           <filter>
             <interface xmlns="http://example.com/schema/1.2/int-stats" name="ethernet0/1">
                <intstats/>
             </interface>
           </filter>
         </get>
       </rpc>

       <rpc-reply message-id="109" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
          <data xmlns="http://example.com/schema/1.2/int-stats">
            <interface name="ethernet0/1">
               <intstats>
                  <inPkts>9456823</inPkts>
                  <inOctets>1228484566</inOctets>
                  <inErrors>4326</inErrors>
                  <outPkts>4821050</outPkts>
                  <outOctets>634712154</outOctets>
                  <outErrors>2096</outErrors>
               </intstats>
            </interface>
          </data>
       </rpc-reply>



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5.8 <close-session>

   Description:

      Request graceful termination of a NETCONF session.

      When a NETCONF entity receives a <close-session> request, it will
      gracefully close the session.  Any operations currently in process
      will be allowed to complete.  When any in-process operations have
      completed, the NETCONF entity will release any locks and resources
      associated with the session and gracefully close any associated
      connections.

   Positive Response:

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

   Negative Response:

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

   Example:

          <rpc message-id="110" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
            <close-session/>
          </rpc>

          <rpc-reply message-id="110" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
            <ok/>
          </rpc-reply>


5.9 <kill-session>

   Description:

      Force the termination of a NETCONF session.

      When a NETCONF entity receives a <kill-session> request for an
      open session, it will abort any operations currently in process,
      release any locks and resources associated with the session and
      close any associated connections.

   Parameters:





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      session-id:

         Session identifier of the NETCONF session to be terminated.  If
         this value is equal to the current session ID, a 'Bad Value'
         error is returned.

   Positive Response:

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

   Negative Response:

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

   Example:

          <rpc message-id="110" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
            <kill-session>
              <session-id>4</session-id>
            </kill-session>
          </rpc>

          <rpc-reply message-id="110" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
            <ok/>
          </rpc-reply>
























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6. Capabilities

   This section defines a set of capabilities that a client or a server
   MAY implement.  Each peer advertises its capabilities by sending them
   during an initial capabilities exchange.  Each peer needs to
   understand only those capabilities that it might use and must be able
   to process and ignore any capability received from the other peer
   that it does not require or does not understand.

   Additional capabilities can be defined using the template in Appendix
   D.  Future capability definitions may be published as standards by
   standards bodies or published as propriety by vendors.

   A NETCONF capability is identified with a URI.  The base capabilities
   are defined using URNs following the method described in RFC 3553
   [6].

      urn:ietf:params:netconf:base:1.0#{name}

   Capabilities defined in this document have the following format:

      urn:ietf:params:xml:ns:netconf:base:1.0#{name}

   where {name} is the name of the capability.  Capabilities are often
   referenced in discussions and email using the shorthand #{name}.  For
   example, the foo capability would have the formal name
   "urn:ietf:params:xml:ns:netconf:base:1.0#foo" and be called "#foo".
   The shorthand form MUST NOT be used inside the protocol.

6.1 Capabilities Exchange

   A NETCONF capability is a set of additional functionality implemented
   on top of the base NETCONF specification.  The capability is
   distinguished by a URI.

   Capabilities are advertised in messages sent on the NETCONF channel
   when each peer starts operation.  When the NETCONF channel is opened,
   each peer sends a <hello> element containing a list of that peer's
   capabilities.

   In the following example, the peer advertises the base NETCONF
   capability, one NETCONF capability defined in the base NETCONF
   document, and one vendor-specific capability.








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   <hello>
     <capabilities>
       <capability>urn:ietf:params:xml:ns:netconf:base:1.0</capability>
       <capability>urn:ietf:params:xml:ns:netconf:base:1.0#startup</capability>
       <capability>http:/example.net/router/2.3/core#cool-feature</capability>
     </capabilities>
   </hello>

   Each peer sends its <hello> element simultaneously as soon as the
   connection is open.  A peer MUST NOT wait to receive the capability
   set from the other side before sending its own set.

6.2 Writable-Running Capability

6.2.1 Description

   The #writable-running capability indicates that the device supports
   writes directly to the <running> configuration datastore.  In other
   words, the device supports edit-config and copy-config operations
   where the <running> configuration is the target.

6.2.2 Dependencies

   None.

6.2.3 Capability and Namespace

   The #writable-running capability is identified by the following
   capability string:

      urn:ietf:params:xml:ns:netconf:base:1.0#writable-running

   The #writable-running capability uses the base NETCONF namespace URN.

6.2.4 New Operations

   None.

6.2.5 Modifications to Existing Operations

6.2.5.1 <edit-config>

   The #writable-running capability modifies the <edit-config> operation
   to accept the <running> element as a <target>.

6.2.5.2 <copy-config>

   The #writable-running capability modifies the <copy-config> operation



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   to accept the <running> element as a <target>.

6.3 Candidate Configuration Capability

6.3.1 Description

   The candidate configuration capability, #candidate, indicates that
   the device supports a candidate configuration datastore, which is
   used to hold configuration data that can manipulated without
   impacting the device's current configuration.  The candidate
   configuration is a full configuration data set that serves as a work
   place for creating a manipulating configuration data.  Additions,
   deletions, and changes may be made to this data to construct the
   desired configuration data.  A <commit> operation may be performed at
   any time that causes the device's running configuration to be set to
   the value of the candidate configuration.

   The candidate configuration can be used as a source or target of any
   operation with a <source> or <target> parameter.  The <candidate>
   element is used to indicate the candidate configuration:

        <rpc message-id="112" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
          <operation>
            <source>
              <candidate/>
            </source>
          </operation>
        </rpc>

   The candidate configuration may be shared among multiple sessions.
   Unless a client has specific information that the candidate
   configuration is not shared (for example, through another
   capability), it must assume that other sessions may be able to modify
   the candidate configuration at the same time.  It is therefore
   prudent for a client to lock the candidate configuration before
   modifying it.

   The client can discard any changes since the last <commit> operation
   by executing the <discard-changes> operation.  The candidate
   configuration's content then reverts to the current committed
   configuration.

6.3.2 Dependencies

   None.

6.3.3 Capability and Namespace




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   The #candidate capability is identified by the following capability
   string:

      urn:ietf:params:xml:ns:netconf:base:1.0#candidate

   The #candidate capability uses the base NETCONF namespace URN.

6.3.4 New Operations

6.3.4.1 <commit>

   Description:

         When a candidate configuration's content is complete, the
         configuration data can be committed, publishing the data set to
         the rest of the device and requesting the device to conform to
         the behavior described in the new configuration.

         To commit the candidate configuration as the device's new
         current configuration, use the <commit> operation.

         The <commit> operation instructs the device to implement the
         configuration data contained in the candidate configuration.

         If the system does not have the #candidate capability, the
         <commit> operation is not available.

   Positive Response:

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

   Negative Response:

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

   Example:

       <rpc message-id="113" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <commit/>
       </rpc>

       <rpc-reply message-id="113" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>





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6.3.4.2 <discard-changes>

   If the client decides that the candidate configuration should not be
   committed, the <discard-changes> operation can be used to revert the
   candidate configuration to the current committed configuration.

     <rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <discard-changes/>
     </rpc>

    This operation discards any uncommitted changes.

6.3.5 Modifications to Existing Operations

6.3.5.1 <lock> and <unlock>

   The candidate configuration can be locked using the <lock> operation
   with the <candidate> element as the <target> parameter:

     <rpc message-id="115" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <lock>
         <target>
           <candidate/>
         </target>
       </lock>
     </rpc>

    Similarly, the candidate configuration is unlocked using the
   <candidate> element as the <target> parameter:

     <rpc message-id="1151" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <unlock>
         <target>
           <candidate/>
         </target>
       </unlock>
     </rpc>

   On devices implementing the #candidate capability the default target
   of the <lock> and <unlock> operations is the candidate configuration
   datastore.

   When a client fails with outstanding changes to the candidate
   configuration, recovery can be difficult.  To facilitate easy
   recovery, any outstanding changes are discarded when the lock is
   released, whether explicitly with the <unlock> operation or
   implicitly from session failure.




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6.3.5.2 <get-config> and <edit-config>

   The candidate configuration is the default target for the
   <edit-config> and <get-config> operations.  It may be explicitly
   named using the <candidate> element:

     <rpc message-id="117" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <get-config>
         <source>
           <candidate/>
         </source>
       </get-config>
     </rpc>


6.4 Confirmed Commit Capability

6.4.1 Description

   The #confirmed-commit capability indicates that the agent will
   support the <confirmed> and <confirm-timeout> parameters for the
   <commit> protocol operation.  See section Section 6.3 for further
   details on the <commit> operation.

   For shared configurations, this feature can cause other configuration
   changes (for example, via other NETCONF sessions) to be inadvertently
   altered or removed, unless the configuration locking feature is used
   (in other words, lock obtained before the edit-config operation is
   started).  Therefore, it is strongly suggested that in order to use
   this feature with shared configuration databases, configuration
   locking must also be available and used properly.

6.4.2 Dependencies

   The #confirmed-commit capability is only relevant if the #candidate
   capability is also supported.

6.4.3 Capability and Namespace

   The #confirmed-commit capability is identified by the following
   capability string:

      urn:ietf:params:xml:ns:netconf:base:1.0#confirmed-commit

   The #confirmed-commit capability uses the base NETCONF namespace URN.






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6.4.4 New Operations

   None.

6.4.5 Modifications to Existing Operations

6.4.5.1 <commit>

   The #confirmed-commit capability allows 2 additional parameters to
   the <commit> operation

   confirmed:

         The <confirmed> element indicates that the <commit> operation
         MUST be reverted if a confirming commit is not issued within
         ten (10) minutes.  The timeout period can be adjusted with the
         <confirm-timeout> element.

   confirm-timeout:

         Timeout period for confirmed commit, in minutes.


       <rpc message-id="114" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <commit>
           <confirmed/>
           <confirm-timeout>20</confirm-timeout>
         </commit>
       </rpc>

       <rpc-reply message-id="114" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>


6.5 Rollback on Error Capability

6.5.1 Description

   This capability indicates that the agent will support the
   rollback-on-error value in the <error-option> parameter to the
   <edit-config> operation.

   For shared configurations, this feature can cause other configuration
   changes (for example, via other NETCONF sessions) to be inadvertently
   altered or removed, unless the configuration locking feature is used
   (in other words, lock obtained before the edit-config operation is
   started).  Therefore, it is strongly suggested that in order to use



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   this feature with shared configuration databases, configuration
   locking must also be available and used properly.

6.5.2 Dependencies

   None

6.5.3 Capability and Namespace

   The #rollback-on-error capability is identified by the following
   capability string:

      urn:ietf:params:xml:ns:netconf:base:1.0#rollback-on-error

   The #rollback-on-error capability uses the base NETCONF namespace
   URN.

6.5.4 New Operations

   None.

6.5.5 Modifications to Existing Operations

6.5.5.1 <edit-config>

   The #rollback-on-error capability allows the rollback-on-error value
   to the <error-option> parameter on the <edit-config> operation.


       <rpc message-id="114" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <edit-config rollback-on-error="yes">
           <error-option>rollback-on-error</error-option>
           <target>
             <running/>
           </target>
           <config xmlns="http://example.com/schema/1.2/config">
             <interface>
               <name>Ethernet0/0</name>
               <mtu>100000</mtu>
             </interface>
           </config>
         </edit-config>
       </rpc>

       <rpc-reply message-id="114" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
         <ok/>
       </rpc-reply>




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6.6 Validate Capability

6.6.1 Description

   Validation consists of checking a candidate configuration for
   syntactical and semantic errors before applying the configuration to
   the device.

   If this capability is advertised, the device supports the <validate>
   protocol operation and checks at least for syntax errors.  In
   addition, this capability supports the validate parameter to the
   <edit-config> operation and, when it is provided, checks at least for
   syntax errors.

6.6.2 Dependencies

   None.

6.6.3 Capability and Namespace

   The #validate capability is identified by the following capability
   string:

      urn:ietf:params:xml:ns:netconf:base:1.0#validate

   The #validate capability uses the base NETCONF namespace URN.

6.6.4 New Operations

6.6.4.1 <validate>

   Description:

         This protocol operation validates the contents of the specified
         configuration.

   Parameters:

      source:

            Name of the configuration datastore being validated, such as
            <candidate>.

   Positive Response:

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




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   Negative Response:

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

         A validate operation can fail for any of the following reasons:

         +  Syntax errors

         +  Missing parameters

         +  References to undefined configuration data

   Example:

        <rpc message-id="118" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
          <validate>
            <candidate/>
          </validate>
        </rpc>

        <rpc-reply message-id="118" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
          <ok/>
        </rpc-reply>


6.7 Distinct Startup Capability

6.7.1 Description

   The device supports separate running and startup configuration
   datastores.  Operations which affect the running configuration will
   not be automatically copied to the startup configuration.  An
   explicit <copy-config> operation from the <running> to the <startup>
   must be invoked to update the startup configuration to the current
   contents of the running configuration.  NETCONF protocol operations
   refer to the startup datastore using the <startup> element.

6.7.2 Dependencies

   None.

6.7.3 Capability and Namespace

   The #startup capability is identified by the following capability
   string:

      urn:ietf:params:xml:ns:netconf:base:1.0#startup



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   The #startup capability uses the base NETCONF namespace URN.

6.7.4 New Operations

   None.

6.7.5 Modifications to Existing Operations

6.7.5.1 <copy-config>

   To save the startup configuration, use the copy-config command to
   copy the <running> configuration datastore to the  <startup>
   configuration datastore.

           <rpc message-id="119" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
             <copy-config>
               <source>
                 <running/>
               </source>
               <target>
                 <startup/>
               </target>
             </copy-config>
           </rpc>


6.8 URL Capability

6.8.1 Description

   The NETCONF peer has the ability to accept the <url> element in
   <source> and <target> parameters.  The capability is further
   identified by URL arguments indicating the protocols supported.

6.8.2 Dependencies

   None.

6.8.3 Capability and Namespace

   The #url capability is identified by the following capability string:

      urn:ietf:params:xml:ns:netconf:base:1.0#url?protocol={protocol-name,...}

   The #url capability uses the base NETCONF namespace URN.

   The #url capability URI MUST contain a "protocol" argument assigned a
   comma-separated list of protocol names indicating which protocols the



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   NETCONF peer supports.  For example:

      urn:ietf:params:xml:ns:netconf:base:1.0#url?protocol=http,ftp,file

   The #url capability uses the base NETCONF namespace URN.

6.8.4 New Operations

   None.

6.8.5 Modifications to Existing Operations

6.8.5.1 <edit-config>

   The #url capability modifies the <edit-config> operation to accept
   the <url> element as the <config> parameter.

6.8.5.2 <copy-config>

   The #url capability modifies the <copy-config> operation to accept
   the <url> element as the value of the the <source> and the <target>
   parameters.

6.8.5.3 <delete-config>

   The #url capability modifies the <delete-config> operation to accept
   the <url> element as the value of the the <target> parameters.  If
   this parameter contains a URL, then it should identify a local
   configuration file.

6.8.5.4 <validate>

   The #url capability modifies the <validate> operation to accept the
   <url> element as the value of the the <source> parameter.

















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7. XML Usage Guidelines for NETCONF

   XML serves as an encoding format for NETCONF, allowing complex
   hierarchical data to be expressed in a text format that can be read,
   saved, and manipulated with both traditional text tools and tools
   specific to XML.

   To simplify manipulation of NETCONF content, use of XML is restricted
   to a simple subset of XML, as described in this section.

7.1 No DTDs

   Document type declarations (DTDs) are not permitted to appear in
   NETCONF content.

7.2 Avoid Mixed Content

   Mixed content is defined as elements that can contain both data and
   other elements.  Elements in NETCONF can contain either data or
   additional elements only.

   This greatly simplifies the complexity of parsing XML, especially in
   the area of significant whitespace.  Whitespace inside data elements
   is significant.  Whitespace outside data elements is not.

       <valid>
         <element>data</element>
         <more>data</more>
       </valid>

       <not-valid>
         <element>data<more>data</more>maybe some</element>
       </not-valid>


7.3 Use an Explicit Namespace on Attributes

   All attributes should be prefixed so that they belong to a specific
   namespace.  This encourages meaningful definitions that are free of
   collisions.

      <valid xmlns="http://valid/" xmlns:v="http://valid/" v:foo="cool"></valid>

      <not-valid xmlns="http://not-valid/" foo="not-cool"></not-valid>







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7.4 Use Container Elements for Lists

   When encoding lists with multiple instances, use a distinct container
   element, preferably the plural form of the instance element.

   In this example, the element 'grommet' is contained within the
   'grommets' element.

       <valid>
         <grommets>
           <grommet>....</grommet>
           <grommet>....</grommet>
           <grommet>....</grommet>
         </grommets>
       </valid>

   Use of container elements allows simpler manipulation of lists and
   list members.

7.5 Elements and Attributes

   The choice of elements and attributes has been widely discussed, but
   no absolute guidelines exist.  When designing encoding rules for
   NETCONF content, the following guidelines should be used:

7.5.1 Consider Attributes as Metadata

   Attributes should contain metadata about the element, not true data.
   By extension, vital information should not be encoded in attributes.

7.5.2 Consider the Lack of Extensibility of Attributes

   Attributes are unordered, can appear only once, and can have no
   children.  Data scenarios which must leave room for future expansion
   (in future specifications or future software releases) should avoid
   attributes.

7.6 Proper Tag Names

   When choosing element names, consider the following guidelines:

   o  Prefer ASCII (7-bit).

   o  Prefer lowercase.

   o  Prefer dashes to underscores.

   o  Prefer full words.  Note that "config" is considered a full word.



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   These are guidelines only and should be considered secondary to the
   need for consistency with existing vocabularies.  For example, when
   encoding MIB variables names in NETCONF, use the existing names
   (ifAddr) instead of shifting to these guidelines (if-address).  These
   guidelines are valuable when no common vocabulary exists, because
   they help to avoid the scenario in which a dozen developers choose a
   dozen names that differ in ways that lead to frustrating
   inconsistencies, such as ifaddr, if-addr, if-address,
   interface-address, intf-addr, iaddr, and iface-addr.










































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8. Security Considerations

   Configuration information is by its very nature sensitive.  Its
   transmission in the clear and without integrity checking leaves
   devices open to classic so-called "person in the middle" attacks.
   Configuration information often times contains passwords, user names,
   service descriptions, and topological information, all of which are
   sensitive.  Because of this, this protocol should be implemented
   carefully with adequate attention to all manner of attack one might
   expect to experience with other management interfaces.

   The protocol, therefore, must minimally support options for both
   privacy and authentication.  It is anticipated that the underlying
   protocol (SSH, BEEP, etc) will provide for both privacy and
   authentication, as is required.  It is further expected that the
   identity of each end of a NETCONF session will be available to the
   other in order to determine authorization for any given request.  One
   could also easily envision additional information such as transport
   and encryption methods being made available for purposes of
   authorization.  NETCONF itself provide no means to reauthenticate,
   much less authenticate.  All such actions occur at lower layers.

   Different environments may well allow different rights prior to and
   then after authentication.  Thus, an authorization model is not
   specified in this document.  When an operation is not properly
   authorized then a simple "permission denied" is sufficient.  Note
   that authorization information may be exchanged in the form of
   configuration information, which is all the more reason to ensure the
   security of the connection.

   That having been said, it is important to recognize that some
   commands are clearly more sensitive by nature than others.  For
   instance, <copy-config> to the startup or running configurations is
   clearly not a normal provisioning operation, where-as <edit-config>
   is.  Similarly, just because someone says go write a configuration
   through the URL capability at a particular place does not mean that
   an element should do it without proper authorization.

   The <lock> operation will demonstrate that use of NETCONF is intended
   for use by systems that have at least some trust of the
   administrator.  As specified in this document, it is possible to lock
   portions of a configuration that a principle might not otherwise have
   access to.  After all, the entire configuration is locked.  To
   mitigate this problem there are two approaches.  It is possible to
   kill another netconf session programmatically from within netconf if
   one knows the session identifier of the offending session.  The other
   possible way to break a lock is to provide an function within the
   craft interface.



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9. IANA Considerations

   TBD.
















































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10. Authors and Acknowledgements

   This document was written by:

      Andy Bierman, Cisco Systems

      Ken Crozier, Cisco Systems

      Rob Enns, Juniper Networks

      Ted Goddard, IceSoft

      Eliot Lear, Cisco Systems

      David Perkins

      Phil Shafer, Juniper Networks

      Steve Waldbusser

      Margaret Wasserman, ThingMagic






























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Normative References

   [1]  Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
        "Extensible Markup Language (XML) 1.0 (Second Edition)", W3C REC
        REC-xml-20001006, October 2000.

   [2]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.

   [3]  Myers, J., "Simple Authentication and Security Layer (SASL)",
        RFC 2222, October 1997.

   [4]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC
        2246, January 1999.

   [5]  Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote
        Authentication Dial In User Service (RADIUS)", RFC 2865, June
        2000.

   [6]  Mealling, M., Masinter, L., Hardie, T. and G. Klyne, "An IETF
        URN Sub-namespace for Registered Protocol Parameters", BCP 73,
        RFC 3553, June 2003.





























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Informative References

   [7]   Clark, J., "XSL Transformations (XSLT) Version 1.0", W3C REC
         REC-xslt-19991116, November 1999.

   [8]   Hollenbeck, S., Rose, M. and L. Masinter, "Guidelines for the
         Use of Extensible Markup Language (XML) within IETF Protocols",
         BCP 70, RFC 3470, January 2003.

   [9]   Boyer, J., "Canonical XML Version 1.0", RFC 3076, March 2001.

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

   [11]  Ylonen, T., Kivinen, T., Saarinen, M., Rinne, T. and S.
         Lehtinen, "SSH Protocol Architecture",
         draft-ietf-secsh-architecture-15 (work in progress), October
         2003.


Author's Address

   Rob Enns
   Juniper Networks
   1194 North Mathilda Ave
   Sunnyvale, CA  94089
   US

   EMail: rpe@juniper.net






















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Appendix A. NETCONF Error List

   Tag:         TOO_BIG
   Error-type:  transport, rpc, protocol, application
   Severity:    error
   Error-info:  none
   Description: The request or response (that would be generated) is too
                large for the implementation to handle.

   Tag:         MISSING_ATTRIBUTE
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  <bad-attribute> : name of the missing attribute
                <bad-element> : name of the element that should
                contain the missing attribute
   Description: An expected attribute is missing

   Tag:         BAD_ATTRIBUTE
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  <bad-attribute> : name of the attribute w/ bad value
                <bad-element> : name of the element that contains
                the attribute with the bad value
   Description: An attribute value is not correct; e.g., wrong type,
                out of range, pattern mismatch

   Tag:         UNKNOWN_ATTRIBUTE
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  <bad-attribute> : name of the unexpected attribute
                <bad-element> : name of the element that contains
                the unexpected attribute
   Description: An unexpected attribute is present

   Tag:         MISSING_ELEMENT
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  <bad-element> : name of the missing element
   Description: An expected element is missing

   Tag:         BAD_ELEMENT
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  <bad-element> : name of the element w/ bad value
   Description: An element value is not correct; e.g., wrong type,
                out of range, pattern mismatch

   Tag:         UNKNOWN_ELEMENT



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   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  <bad-element> : name of the unexpected element
   Description: An unexpected element is present

   Tag:         ACCESS_DENIED
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  none
   Description: Access to the requested RPC, protocol operation,
                or application data model is denied because
                authorization failed

   Tag:         LOCK_DENIED
   Error-type:  protocol
   Severity:    error
   Error-info:  <session-id> : session ID of session holding the
                requested lock, or zero to indicate a non-NETCONF
                entity holds the lock
   Description: Access to the requested lock is denied because the
                lock is currently held by another entity

   Tag:         RESOURCE_DENIED
   Error-type:  transport, rpc, protocol, application
   Severity:    error
   Error-info:  none
   Description: Request could not be completed because of insufficient
                resources

   Tag:         ROLLBACK_FAILED
   Error-type:  protocol, application
   Severity:    error
   Error-info:  none
   Description: Request to rollback some configuration change (via
                rollback-on-error or discard-changes operations) was
                not completed for some reason.

   Tag:         DATA_EXISTS
   Error-type:  application
   Severity:    error
   Error-info:  none
   Description: Request could not be completed because the relevant
                data model content already exists. For example,
                a 'create' operation was attempted on data which
                already exists.

   Tag:         DATA_MISSING
   Error-type:  application



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   Severity:    error
   Error-info:  none
   Description: Request could not be completed because the relevant
                data model content does not exist.  For example,
                a 'modify' or 'delete' operation was attempted on
                data which does not exist.

   Tag:         OPERATION_NOT_SUPPORTED
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  none
   Description: Request could not be completed because the requested
                operation is not supported by this implementation.

   Tag:         OPERATION_FAILED
   Error-type:  rpc, protocol, application
   Severity:    error
   Error-info:  none
   Description: Request could not be completed because the requested
                operation failed for some reason not covered by
                any other error condition.


   Tag:         PARTIAL_OPERATION
   Error-type:  application
   Severity:    error
   Error-info:  <ok-element> : identifies an element in the data model
                for which the requested operation has been completed
                for that node and all its child nodes.  This element
                can appear zero or more times in the <error-info>
                container.

                <err-element> : identifies an element in the data model
                for which the requested operation has failed for that
                node and all its child nodes. This element
                can appear zero or more times in the <error-info>
                container.

                <noop-element> : identifies an element in the data model
                for which the requested operation was not attempted for
                that node and all its child nodes. This element
                can appear zero or more times in the <error-info>
                container.

   Description: Some part of the requested operation failed or was
                not attempted for some reason.  Full cleanup has
                not been performed (e.g., rollback not supported)
                by the agent.  The error-info container is used



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                to identify which portions of the application
                data model content for which the requested operation
                has succeeded (<ok-element>), failed (<bad-element>),
                or not attempted (<noop-element>).















































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Appendix B. XML Schema for NETCONF RPC and Protocol Operations


   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema targetNamespace="urn:ietf:params:xml:ns:netconf:base:1.0" elementFormDefault="qualified" attributeFormDefault="unqualified" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <xs:complexType name="rpcType">
       <xs:sequence>
         <xs:element ref="rpcOperation"/>
       </xs:sequence>
       <xs:attribute name="message-id" type="xs:string" use="required"/>
     </xs:complexType>
     <xs:element name="rpc" type="rpcType"/>

     <xs:simpleType name="SessionId">
       <xs:restriction base="xs:unsignedInt"/>
     </xs:simpleType>

     <xs:simpleType name="ErrorType">
       <xs:restriction base="xs:string">
         <xs:enumeration value="transport"/>
         <xs:enumeration value="rpc"/>
         <xs:enumeration value="protocol"/>
         <xs:enumeration value="application"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="ErrorTag">
       <xs:restriction base="xs:string">
         <xs:enumeration value="TOO_BIG"/>
         <xs:enumeration value="MISSING_ATTRIBUTE"/>
         <xs:enumeration value="BAD_ATTRIBUTE"/>
         <xs:enumeration value="UNKNOWN_ATTRIBUTE"/>
         <xs:enumeration value="MISSING_ELEMENT"/>
         <xs:enumeration value="BAD_ELEMENT"/>
         <xs:enumeration value="UNKNOWN_ELEMENT"/>
         <xs:enumeration value="ACCESS_DENIED"/>
         <xs:enumeration value="LOCK_DENIED"/>
         <xs:enumeration value="RESOURCE_DENIED"/>
         <xs:enumeration value="ROLLBACK_FAILED"/>
         <xs:enumeration value="DATA_EXISTS"/>
         <xs:enumeration value="DATA_MISSING"/>
         <xs:enumeration value="OPERATION_NOT_SUPPORTED"/>
         <xs:enumeration value="OPERATION_FAILED"/>
         <xs:enumeration value="PARTIAL_OPERATION"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:simpleType name="ErrorSeverity">



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       <xs:restriction base="xs:string">
         <xs:enumeration value="error"/>
         <xs:enumeration value="warning"/>
       </xs:restriction>
     </xs:simpleType>

     <xs:complexType name="rpc-errorType">
       <xs:sequence>
         <xs:element name="error-type" type="ErrorType"/>
         <xs:element name="error-tag" type="ErrorTag"/>
         <xs:element name="error-severity" type="ErrorSeverity"/>
         <xs:element name="error-app-tag" type="xs:string" minOccurs="0"/>
         <xs:element name="error-path" type="xs:string" minOccurs="0"/>
         <xs:element name="error-message" type="xs:string" minOccurs="0"/>
         <xs:element name="error-info" type="xs:any" minOccurs="0"/>
       </xs:sequence>
     </xs:complexType>

     <!-- Standard elements used in the error-info container  -->
     <xs:element name="bad-attribute" type="xs:QName"/>
     <xs:element name="bad-element" type="xs:QName"/>
     <xs:element name="ok-element" type="xs:QName"/>
     <xs:element name="err-element" type="xs:QName"/>
     <xs:element name="noop-element" type="xs:QName"/>
     <xs:element name="session-id" type="SessionId"/>

     <xs:complexType name="rpc-replyType">
       <xs:choice>
         <xs:element name="ok" minOccurs="0"/>
         <xs:element name="rpc-error" type="rpc-errorType" minOccurs="0"/>
         <xs:element ref="config" minOccurs="0"/>
         <xs:element ref="data" minOccurs="0"/>
       </xs:choice>
       <xs:attribute name="message-id" type="xs:string" use="required"/>
     </xs:complexType>
     <xs:element name="rpc-reply" type="rpc-replyType"/>
     <xs:simpleType name="test-optionType">
       <xs:restriction base="xs:string">
         <xs:enumeration value="test"/>
         <xs:enumeration value="test-then-set"/>
         <xs:enumeration value="set"/>
       </xs:restriction>
     </xs:simpleType>
     <xs:element name="test-option" type="test-optionType"/>
     <xs:simpleType name="error-optionType">
       <xs:restriction base="xs:string">
         <xs:enumeration value="stop-on-error"/>
         <xs:enumeration value="ignore-error"/>



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       </xs:restriction>
     </xs:simpleType>
     <xs:element name="error-option" type="error-optionType"/>
     <xs:complexType name="rpcOperationType">
       <xs:annotation>
       </xs:annotation>
     </xs:complexType>
     <xs:element name="rpcOperation" type="rpcOperationType" abstract="true"/>
     <xs:complexType name="config-inlineType">
       <xs:complexContent>
         <xs:extension base="xs:anyType">
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="config" type="config-inlineType"/>
     <xs:element name="filter" type="config-inlineType"/>
     <xs:complexType name="config-nameType"/>
     <xs:element name="config-name" type="config-nameType" abstract="true"/>
     <xs:element name="startup" type="config-nameType" substitutionGroup="config-name"/>
     <xs:element name="candidate" type="config-nameType" substitutionGroup="config-name"/>
     <xs:element name="running" type="config-nameType" substitutionGroup="config-name"/>
     <xs:complexType name="config-uriType">
       <xs:simpleContent>
         <xs:extension base="xs:anyURI">
          </xs:extension>
       </xs:simpleContent>
     </xs:complexType>
     <xs:element name="url" type="config-uriType"/>
     <xs:complexType name="rpcOperationSourceType">
       <xs:choice>
         <xs:element ref="config"/>
         <xs:element ref="config-name"/>
         <xs:element ref="url"/>
       </xs:choice>
     </xs:complexType>
     <xs:element name="source" type="rpcOperationSourceType"/>
     <xs:complexType name="rpcOperationTargetType">
       <xs:choice>
         <xs:element ref="config-name"/>
         <xs:element ref="url"/>
       </xs:choice>
     </xs:complexType>
     <xs:element name="target" type="rpcOperationTargetType"/>
     <xs:complexType name="get-configType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="source"/>



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             <xs:element ref="filter" minOccurs="0"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="get-config" type="get-configType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="edit-configType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="source" minOccurs="0"/>
             <xs:element ref="target"/>
             <xs:element ref="test-option" minOccurs="0"/>
             <xs:element ref="error-option" minOccurs="0"/>
             <xs:element ref="config" minOccurs="0"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="edit-config" type="edit-configType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="copy-configType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="source"/>
             <xs:element ref="target"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="copy-config" type="copy-configType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="delete-configType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="target"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="delete-config" type="delete-configType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="getType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="filter" minOccurs="0"/>
           </xs:sequence>
         </xs:extension>



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       </xs:complexContent>
     </xs:complexType>
     <xs:element name="get" type="getType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="lockType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="target"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="lock" type="lockType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="unlockType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="target"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="unlock" type="unlockType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="validateType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element ref="source"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="validate" type="validateType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="commitType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element name="confirmed" minOccurs="0"/>
             <xs:element name="confirmed-timeout" minOccurs="0"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="commit" type="commitType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="discard-changesType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType"/>
       </xs:complexContent>



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     </xs:complexType>
     <xs:element name="discard-changes" type="discard-changesType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="close-sessionType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType"/>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="close-session" type="close-sessionType" substitutionGroup="rpcOperation"/>
     <xs:complexType name="kill-sessionType">
       <xs:complexContent>
         <xs:extension base="rpcOperationType">
           <xs:sequence>
             <xs:element name="session-id" type="SessionId" minOccurs="0"/>
           </xs:sequence>
         </xs:extension>
       </xs:complexContent>
     </xs:complexType>
     <xs:element name="kill-session" type="kill-sessionType" substitutionGroup="rpcOperation"/>
   </xs:schema>
































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Appendix C. XML Schema for NETCONF State Data


    <schema
        targetNamespace="http://ietf.org/netconf/1.0/state"
        xmlns="http://www.w3.org/2001/XMLSchema"
        xmlns:xc="http://ietf.org/netconf/1.0/state"
        elementFormDefault="unqualified">

     <annotation>
      <documentation xml:lang="en">
       Initial schema for NETCONF state information.
      </documentation>
     </annotation>

     <element name="netconf-state">
      <complexType>
       <sequence>

        <element name="capabilities">
         <annotation>
          <documentation xml:lang="en">
           List of NETCONF capabilities supported by this device.
          </documentation>
         </annotation>
         <complexType>
          <sequence>
           <element name="capability" type="anyURI"
            minOccurs="0" maxOccurs="unbounded"/>
          </sequence>
         </complexType>
        </element>

        <element name="sessions">
         <annotation>
          <documentation xml:lang="en">
           List of NETCONF sessions currently active on this device.
          </documentation>
         </annotation>
         <complexType>
          <sequence>
           <element name="my-session-id" type="positiveInteger"/>
           <element name="session" type="xc:NetconfSessionInfo"
            minOccurs="0" maxOccurs="unbounded"/>
          </sequence>
         </complexType>
        </element>




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        <element name="configs">
         <annotation>
          <documentation xml:lang="en">
           List of NETCONF configuration databases supported on this device.
          </documentation>
         </annotation>
         <complexType>
          <sequence>
           <element name="config" type="xc:NetconfConfigInfo"
            minOccurs="0" maxOccurs="unbounded"/>
          </sequence>
         </complexType>
        </element>

       </sequence>
      </complexType>
     </element>

     <complexType name="NetconfSessionInfo">
      <sequence>
       <element name="session-id" type="positiveInteger"/>
       <element name="username" type="string"/>
       <element name="login-time" type="dateTime"/>
      </sequence>
     </complexType>

     <complexType name="NetconfConfigInfo">
      <sequence>
       <element name="config-name" type="xc:ConfigName"/>
       <element name="lock-status" type="xc:LockStatus"/>
      </sequence>
     </complexType>

     <complexType name="ConfigName">
      <choice>
       <element name="candidate"/>
       <element name="running"/>
       <element name="startup"/>
      </choice>
     </complexType>

     <complexType name="LockStatus">
      <sequence>
       <element name="lock-state">
        <simpleType>
         <restriction base="string">
          <enumeration value="locked"/>
          <enumeration value="unlocked"/>



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         </restriction>
        </simpleType>
       </element>
       <element name="locked-by" type="positiveInteger"
        minOccurs="0"/>
      </sequence>
     </complexType>

    </schema>










































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Appendix D. Capability Template

D.1 capability-name (template)

D.1.1 Overview

D.1.2 Dependencies

D.1.3 Capability and Namespace

   The {name} is identified by following capability string:

      urn:ietf:params:xml:ns:netconf:base:1.0#{name}

   The {name} capability uses the base NETCONF namespace URN.

D.1.4 New Operations

D.1.4.1 <op-name>

D.1.5 Modifications to Existing Operations

D.1.5.1 <op-name>

   If existing operations are not modified by this capability, this
   section may be omitted.

D.1.6 Interactions with Other Capabilities

   If this capability does not interact with other capabilities, this
   section may be omitted.




















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Appendix E. Configuring Multiple Devices with NETCONF

E.1 Operations on Individual Devices

   Consider the work involved in performing a configuration update
   against a single individual device.  In making a change to the
   configuration, the application needs to build trust that its change
   has been made correctly and that it has not impacted the operation of
   the device.  The application (and the application user) should feel
   confident that their change has not damaged the network.

   Protecting each individual device consists of a number of steps:

   o  Acquiring the configuration lock.

   o  Loading the update.

   o  Validating the incoming configuration.

   o  Checkpointing the running configuration.

   o  Changing the running configuration.

   o  Testing the new configuration.

   o  Making the change permanent (if desired).

   o  Releasing the configuration lock.

   Let's look at the details of each step.

E.1.1 Acquiring the Configuration Lock

   A lock should be acquired to prevent simultaneous updates from
   multiple sources.  If multiple sources are affecting the device, the
   application is hampered in both testing of its change to the
   configuration and in recovery should the update fail.  Acquiring a
   short-lived lock is a simple defense to prevent other parties from
   introducing unrelated changes while.

   The lock can be acquired using the <lock> operation.

      <rpc message-id="201" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <lock>
          <target>
            <running/>
          </target>
        </lock>



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      </rpc>


E.1.2 Loading the Update

   The configuration can be loaded onto the device without impacting the
   running system.  If the #url capability is supported, incoming
   changes can be placed in a local file.

      <rpc message-id="203" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <copy-config>
          <source>
            <config>
              <!-- place incoming configuration here -->
            </config>
          </source>
          <target>
            <url>file://incoming.conf</url>
          </target>
        </copy-config>
      </rpc>

   If the #candidate capability is supported, the candidate
   configuration can be used.

      <rpc message-id="204" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <edit-config>
          <source>
            <config>
              <!-- place incoming configuration here -->
            </config>
          </source>
          <target>
            <candidate/>
          </target>
        </edit-config>
      </rpc>

   If the update fails, the user file can be deleted using the
   <delete-config> operation or the candidate configuration reverted
   using the <discard-changes> operation.

E.1.3 Validating the Incoming Configuration

   Before applying the incoming configuration, it is often useful to
   validate it.  Validation allows the application to gain confidence
   that the change will succeed and simplifies recovery if it does not.




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   If the device supports the #url capability, use the <validate>
   operation with the <source> parameter set to the proper user file:

      <rpc message-id="205" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <validate>
          <source>
            <url>file://incoming.conf</url>
          </source>
        </validate>
      </rpc>

   If the device supports the #candidate capability, some validation
   will be performed as part of loading the incoming configuration into
   the candidate.  For full validation, either pass the <validate>
   parameter during the <edit-config> step given above, or use the
   <validate> operation with the <source> parameter set to <candidate>.

      <rpc message-id="206" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <validate>
          <source>
            <candidate/>
          </source>
        </validate>
      </rpc>


E.1.4 Checkpointing the Running Configuration

   The running configuration can be saved into a local file as a
   checkpoint before loading the new configuration.  If the update
   fails, the configuration can be restored by reloading the checkpoint
   file.

   The checkpoint file can be created using the <copy-config> operation.

      <rpc message-id="207" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <copy-config>
          <source>
            <running/>
          </source>
          <target>
            <url>file://checkpoint.conf</url>
          </target>
        </copy-config>
      </rpc>

   To restore the checkpoint file, reverse the source and target
   parameters.



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E.1.5 Changing the Running Configuration

   When the incoming configuration has been safely loaded onto the
   device and validated, it is ready to impact the running system.

   If the device supports the #url capability, use the <edit-config>
   operation to merge the incoming configuration into the running
   configuration.

      <rpc message-id="208" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <edit-config>
          <source>
            <url>file://incoming.conf</url>
          </source>
          <target>
            <running/>
          </target>
        </edit-config>
      </rpc>

   If the device supports the #candidate capability, use the <commit>
   operation to set the running configuration to the candidate
   configuration.  Use the <confirmed> parameter to allow automatic
   reverting to the original configuration if connectivity to the device
   fails.

      <rpc message-id="209" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <commit>
          <confirmed/>
          <confirm-timeout>15</confirm-timeout>
        </commit>
      </rpc>


E.1.6 Testing the New Configuration

   Now that the incoming configuration has been integrated into the
   running configuration, the application needs to gain trust that the
   change has affected the device in the way intended without affecting
   it negatively.

   To gain this confidence, the application can run tests of the
   operational state of the device.  The nature of the test is dependent
   on the nature of the change and is outside the scope of this
   document.  Such tests may include reachability from the system
   running the application (using ping), changes in reachability to the
   rest of the network (by comparing the device's routing table), or
   inspection of the particular change (looking for operational evidence



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   of the BGP peer that was just added).

E.1.7 Making the Change Permanent

   When the configuration change is in place and the application has
   sufficient faith in the proper function of this change, the
   application should make the change permanent.

   If the device supports the #startup capability, the current
   configuration can be saved to the startup configuration by using the
   startup configuration as the target of the <copy-config> operation.

      <rpc message-id="210" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <copy-config>
          <source>
            <running/>
          </source>
          <target>
            <startup/>
          </target>
        </copy-config>
      </rpc>

   If the device supports the #candidate capability and a confirmed
   commit was requested, the confirming commit must be sent before the
   timeout expires.

      <rpc message-id="211" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <commit/>
      </rpc>


E.1.8 Releasing the Configuration Lock

   When the configuration update is complete, the lock must be released,
   allowing other applications access to the configuration.

   Use the <unlock> operation to release the configuration lock.

      <rpc message-id="212" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
        <unlock/>
      </rpc>


E.2 Operations on Multiple Devices

   When a configuration change requires updates across a number of
   devices, care should be taken to provide the required transaction



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   semantics.  The NETCONF protocol contains sufficient primitives upon
   which transaction-oriented operations can be built.  Providing
   complete transactional semantics across multiple devices is
   prohibitively expensive, but the size and number of windows for
   failure scenarios can be reduced.

   There are two classes of multidevice operations.  The first class of
   allows the operation to fail on individual devices without requiring
   all devices to revert to their original state.  The operation can be
   retried at a later time, or its failure simply reported to the user.
   A example of this class might be adding an NTP server.  For this
   class of operations, failure avoidance and recovery are focused on
   the individual device.  This means recovery of the device, reporting
   the failure, and perhaps scheduling another attempt.

   The second class is more interesting, requiring that the operation
   should complete on all devices or be fully reversed.  The network
   should either be transformed into a new state or be reset to its
   original state.  For example, a change to a VPN may require updates
   to a number of devices.  Another example of this might be adding a
   class-of-service definition.  Leaving the network in a state where
   only a portion of the devices have been updated with the new
   definition will lead to future failures when the definition is
   referenced.

   To give transactional semantics, the same steps used in single device
   operations listed above are used, but are performed in parallel
   across all devices.  Configuration locks should be acquired on all
   target devices and kept until all devices are updated and the changes
   made permanent.  Configuration changes should be uploaded and
   validation performed across all devices.  Checkpoints should be made
   on each device.  Then the running configuration can be changed,
   tested, and made permanent.  If any of these steps fail, the previous
   configurations can be restored on any devices upon which it was
   changed.  After the changes have been completely implemented or
   completely discarded, the locks on each device can be released.















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Appendix F. Change Log

   RFC Editor: Please remove this section before RFC publication.

F.1 draft-ietf-netconf-prot-03

   Refer to the NETCONF issue list for futher detail on the issue
   numbers below.  The issue list is found at http://www.nextbeacon.com/
   netconf/.

   o  Consistent naming of <confirm-timeout> element.

   o  Add #confirmed-commit capability (issue 10.3.2)

   o  Use a URN for the NETCONF namespace (issue 11.1.2) and
      capabilities

   o  Remove #manager capability (issue 11.2.1)

   o  Remove #agent capability (issue 11.2.2)

   o  Add "create" as a value for the operation attribute in
      <edit-config> (issue 13.3.1)

   o  Add #rollback-on-error capability (issue 13.3.2)

   o  Rename <get-all> operation to <get>.

   o  Remove format parameter from two <get-config> and one <get>
      examples missed in the -02 draft (issue 13.3.3).

   o  Add text indicating that the session-id is returned if the lock is
      already held (issue 13.12.3).  Add example of this.

   o  Remove <discard-changes> parameter on the <lock> operation (issue
      13.16.1), all outstanding changes are to be discarded when the
      candidate configuration is unlocked.

   o  Remove section 8.7, guidelines on namespace construction.

   o  Add clarifying text regarding locks held by other entities.

   o  Update the abstract.

   o  Remove mention of the format parameter from the <get-config> and
      <get> operations and the XSD.

   o  Updated security considerations section.



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   o  Removed terminology section, moved session description to protocol
      overview section.

   o  New text describing <rpc-error>.

   o  Updated NETCONF protocol schema (to reflect new <rpc-error>
      details, among other things).

   o  Add <filter> parameter to <get> and <get-config>.  Rename <state>
      response the <get> operation to <data>.

   o  Better description of the <kill-session> operation.

   o  Add <close-session> operation.

   o  Removed format parameter to <copy-config>.

   o  Removed restriction that a changed <candidate/> configuration
      datastore can't be locked.

   o  Add note in section 2 that the application protocol must provide
      an indication of session type (manager or agent) to the NETCONF
      layer.


F.2 draft-ietf-netconf-prot-02

   Refer to the NETCONF issue list for futher detail on the issue
   numbers below.  The issue list is found at http://www.nextbeacon.com/
   netconf/.

   o  Remove <rpc-abort>, <rpc-abort-reply>, and <rpc-progress> (issues
      12.1, 12.2, 12.3).

   o  Remove channels (issues 3.*).

   o  Remove notifications (issues 2.*, 4.2, 13.9, 13.10, 13.11).

   o  Move version number to last component of the capability URI (issue
      11.1.1).

   o  Remove format parameter from <get-config> (issue 13.3.3).

   o  Remove mention of #lock capability from Appendix E.  Locking is a
      mandatory NETCONF operation.

   o  Added text indicating that attributes received in <rpc> should be
      echoed on <rpc-reply> (issue 16.1).



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   o  Reworded Section 7.3 to encourage always prefixing attributes with
      namespaces.

















































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