This is a purely informative rendering of an RFC that includes verified errata. This rendering may not be used as a reference.
The following 'Verified' errata have been incorporated in this document:
EID 1456
Network Working Group R. Enns, Ed.
Request for Comments: 4741 Juniper Networks
Category: Standards Track December 2006
NETCONF Configuration Protocol
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2006).
Abstract
The Network Configuration Protocol (NETCONF) defined in this document
provides mechanisms to install, manipulate, and delete the
configuration of network devices. It uses an Extensible Markup
Language (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 Remote Procedure Call (RPC) layer.
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. Transport Protocol Requirements .................................8
2.1. Connection-Oriented Operation ..............................9
2.2. Authentication, Integrity, and Confidentiality .............9
2.3. Authentication .............................................9
2.4. Mandatory Transport Protocol ..............................10
3. XML Considerations .............................................10
3.1. Namespace .................................................10
3.2. No Document Type Declarations .............................10
4. RPC Model ......................................................10
4.1. <rpc> Element .............................................10
4.2. <rpc-reply> Element .......................................12
4.3. <rpc-error> Element .......................................12
4.4. <ok> Element ..............................................16
4.5. Pipelining ................................................16
5. Configuration Model ............................................16
5.1. Configuration Datastores ..................................16
5.2. Data Modeling .............................................17
6. Subtree Filtering ..............................................17
6.1. Overview ..................................................17
6.2. Subtree Filter Components .................................18
6.2.1. Namespace Selection ................................18
6.2.2. Attribute Match Expressions ........................19
6.2.3. Containment Nodes ..................................19
6.2.4. Selection Nodes ....................................20
6.2.5. Content Match Nodes ................................20
6.3. Subtree Filter Processing .................................22
6.4. Subtree Filtering Examples ................................22
6.4.1. No Filter ..........................................22
6.4.2. Empty Filter .......................................23
6.4.3. Select the Entire <users> Subtree ..................23
6.4.4. Select All <name> Elements within the
<users> Subtree ....................................25
6.4.5. One Specific <user> Entry ..........................26
6.4.6. Specific Elements from a Specific <user> Entry .....27
6.4.7. Multiple Subtrees ..................................28
6.4.8. Elements with Attribute Naming .....................29
7. Protocol Operations ............................................31
7.1. <get-config> ..............................................31
7.2. <edit-config> .............................................34
7.3. <copy-config> .............................................39
7.4. <delete-config> ...........................................41
7.5. <lock> ....................................................42
7.6. <unlock> ..................................................44
7.7. <get> .....................................................45
7.8. <close-session> ...........................................47
7.9. <kill-session> ............................................48
8. Capabilities ...................................................49
8.1. Capabilities Exchange .....................................49
8.2. Writable-Running Capability ...............................50
8.2.1. Description ........................................50
8.2.2. Dependencies .......................................50
8.2.3. Capability Identifier ..............................50
8.2.4. New Operations .....................................51
8.2.5. Modifications to Existing Operations ...............51
8.3. Candidate Configuration Capability ........................51
8.3.1. Description ........................................51
8.3.2. Dependencies .......................................52
8.3.3. Capability Identifier ..............................52
8.3.4. New Operations .....................................52
8.3.5. Modifications to Existing Operations ...............53
8.4. Confirmed Commit Capability ...............................55
8.4.1. Description ........................................55
8.4.2. Dependencies .......................................55
8.4.3. Capability Identifier ..............................56
8.4.4. New Operations .....................................56
8.4.5. Modifications to Existing Operations ...............56
8.5. Rollback on Error Capability ..............................57
8.5.1. Description ........................................57
8.5.2. Dependencies .......................................57
8.5.3. Capability Identifier ..............................57
8.5.4. New Operations .....................................57
8.5.5. Modifications to Existing Operations ...............57
8.6. Validate Capability .......................................58
8.6.1. Description ........................................58
8.6.2. Dependencies .......................................58
8.6.3. Capability Identifier ..............................58
8.6.4. New Operations .....................................58
8.7. Distinct Startup Capability ...............................60
8.7.1. Description ........................................60
8.7.2. Dependencies .......................................60
8.7.3. Capability Identifier ..............................60
8.7.4. New Operations .....................................60
8.7.5. Modifications to Existing Operations ...............60
8.8. URL Capability ............................................61
8.8.1. Description ........................................61
8.8.2. Dependencies .......................................61
8.8.3. Capability Identifier ..............................62
8.8.4. New Operations .....................................62
8.8.5. Modifications to Existing Operations ...............62
8.9. XPath Capability ..........................................63
8.9.1. Description ........................................63
8.9.2. Dependencies .......................................63
8.9.3. Capability Identifier ..............................63
8.9.4. New Operations .....................................63
8.9.5. Modifications to Existing Operations ...............63
9. Security Considerations ........................................64
10. IANA Considerations ...........................................66
10.1. NETCONF XML Namespace ....................................66
10.2. NETCONF XML Schema .......................................66
10.3. NETCONF Capability URNs ..................................66
11. Authors and Acknowledgements ..................................68
12. References ....................................................68
12.1. Normative References .....................................68
12.2. Informative References ...................................69
Appendix A. NETCONF Error List ....................................70
Appendix B. XML Schema for NETCONF RPC and Protocol Operations ....74
Appendix C. Capability Template ...................................86
C.1. capability-name (template) ................................86
C.1.1. Overview ...........................................86
C.1.2. Dependencies .......................................86
C.1.3. Capability Identifier ..............................86
C.1.4. New Operations .....................................86
C.1.5. Modifications to Existing Operations ...............86
C.1.6. Interactions with Other Capabilities ...............86
Appendix D. Configuring Multiple Devices with NETCONF ............87
D.1. Operations on Individual Devices ..........................87
D.1.1. Acquiring the Configuration Lock ...................87
D.1.2. Loading the Update .................................88
D.1.3. Validating the Incoming Configuration ..............89
D.1.4. Checkpointing the Running Configuration ............89
D.1.5. Changing the Running Configuration .................90
D.1.6. Testing the New Configuration ......................91
D.1.7. Making the Change Permanent ........................91
D.1.8. Releasing the Configuration Lock ...................92
D.2. Operations on Multiple Devices ............................92
Appendix E. Deferred Features .....................................93
1. Introduction
The NETCONF protocol defines a simple mechanism through which a
network device can be managed, configuration data 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
straightforward API to send and receive full and partial
configuration data sets.
The NETCONF protocol uses a remote procedure call (RPC) paradigm. 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
management protocol 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 a 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 non-standard capabilities can be
defined with semantic and syntactic rigor. Capabilities are
discussed in Section 8.
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 [8], 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 scripts from a task-oriented,
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
document are to be interpreted as described in RFC 2119 [3].
1.1. Protocol Overview
NETCONF uses a simple RPC-based mechanism to facilitate communication
between a client and a server. The client can be a script or
application typically running as part of a network manager. The
server is typically 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
SHOULD support multiple sessions. Global configuration attributes
can be changed during any authorized session, and the effects 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
+-------------+ +-----------------------------+
(4) | Content | | Configuration data |
+-------------+ +-----------------------------+
| |
+-------------+ +-----------------------------+
(3) | Operations | | <get-config>, <edit-config> |
+-------------+ +-----------------------------+
| |
+-------------+ +-----------------------------+
(2) | RPC | | <rpc>, <rpc-reply> |
+-------------+ +-----------------------------+
| |
+-------------+ +-----------------------------+
(1) | Transport | | BEEP, SSH, SSL, console |
| Protocol | | |
+-------------+ +-----------------------------+
1. The transport protocol layer provides a communication path
between the client and server. NETCONF can be layered over any
transport 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 4 documents this protocol.
3. The operations layer defines a set of base operations invoked as
RPC methods with XML-encoded parameters. Section 7 details the
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
NETCONF implementation. 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 8.
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. To support a capability, the server MUST support any
capabilities upon which it depends.
Section 8 defines the capabilities exchange that allows the client to
discover the server's capabilities. Section 8 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
implementations may define proprietary ones. A 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:
o Comparisons of configuration data sets would be dominated by
irrelevant entries such as different statistics.
o Incoming data could contain nonsensical requests, such as attempts
to write read-only data.
o The data sets would be large.
o Archived data could contain values for read-only data items,
complicating the processing required to restore archived data.
To account for these issues, the NETCONF protocol recognizes the
difference between configuration data and state data and provides
operations for each. The <get-config> operation retrieves
configuration data only, while the <get> operation retrieves
configuration and state data.
Note that the NETCONF protocol is focused on the information required
to get the device into its desired running state. The inclusion of
other important, persistent data is implementation specific. For
example, user files and databases are not treated as configuration
data by the NETCONF protocol.
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.
2. Transport 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 transport protocol that
provides the required set of functionality. It is not bound to any
particular transport protocol, but allows a mapping to define how it
can be implemented over any specific protocol.
The transport protocol MUST provide a mechanism to indicate the
session type (client or server) to the NETCONF protocol layer.
This section details the characteristics that NETCONF requires from
the underlying transport 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 client, the lock persists until either it is
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 7.5.
2.2. Authentication, Integrity, and Confidentiality
NETCONF connections must provide authentication, data integrity, and
confidentiality. NETCONF depends on the transport protocol for this
capability. A NETCONF peer assumes that appropriate levels of
security and confidentiality are provided independently of this
document. For example, connections may be encrypted in TLS [9] or
SSH [10], depending on the underlying protocol.
2.3. Authentication
NETCONF connections must be authenticated. The transport 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 identity has been sufficiently proven.
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 [11] should allow the use of
RADIUS to authenticate NETCONF sessions.
The authentication process should result in an identity whose
permissions are known to the device. These permissions MUST be
enforced during the remainder of the NETCONF session.
2.4. Mandatory Transport Protocol
A NETCONF implementation MUST support the SSH transport protocol
mapping [4].
3. XML Considerations
XML serves as the 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.
This section discusses a small number of XML-related considerations
pertaining to NETCONF.
3.1. Namespace
All NETCONF protocol elements are defined in the following namespace:
urn:ietf:params:xml:ns:netconf:base:1.0
NETCONF capability names MUST be URIs [5]. NETCONF capabilities are
discussed in Section 8.
3.2. No Document Type Declarations
Document type declarations MUST NOT appear in NETCONF content.
4. RPC Model
The NETCONF protocol uses an RPC-based communication model. NETCONF
peers use <rpc> and <rpc-reply> elements to provide transport
protocol-independent framing of NETCONF requests and responses.
4.1. <rpc> Element
The <rpc> element is used to enclose a NETCONF request sent from the
client to the server.
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 be
used 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>
<!-- method parameters here... -->
</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="101"
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>
</rpc>
The following example invokes a <rock-the-house> method with a
<zip-code> parameter of "27606-0100":
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<rock-the-house xmlns="http://example.net/rock/1.0">
<zip-code>27606-0100</zip-code>
</rock-the-house>
</rpc>
The following example invokes the NETCONF <get> method with no
parameters:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get/>
</rpc>
4.2. <rpc-reply> Element
The <rpc-reply> message is sent in response to an <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:
The following <rpc> element invokes the NETCONF <get> method and
includes an additional attribute called "user-id". Note that the
"user-id" attribute is not in the NETCONF namespace. The returned
<rpc-reply> element returns the "user-id" attribute, as well as the
requested content.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:ex="http://example.net/content/1.0"
ex:user-id="fred">
<get/>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:ex="http://example.net/content/1.0"
ex:user-id="fred">
<data>
<!-- contents here... -->
</data>
</rpc-reply>
4.3. <rpc-error> Element
The <rpc-error> element is sent in <rpc-reply> messages if an error
occurs during the processing of an <rpc> request.
If a server encounters multiple errors during the processing of an
<rpc> request, the <rpc-reply> MAY contain multiple <rpc-error>
elements. However, a server is not required to detect or report more
than one <rpc-error> element, if a request contains multiple errors.
A server is not required to check for particular error conditions in
a specific sequence. A server MUST return an <rpc-error> element if
any error conditions occur during processing and SHOULD return an
<rpc-error> element if any warning conditions occur during
processing.
A server MUST NOT return application-level- or data-model-specific
error information in an <rpc-error> element for which the client does
not have sufficient access rights.
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: Contains a string identifying the error condition. See
Appendix A for allowed values.
error-severity: Contains a string identifying the error severity, as
determined by the device. One of:
* error
* warning
error-app-tag: Contains a string identifying the data-model-specific
or implementation-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: Contains the absolute XPath [2] expression identifying
the element path to the node that 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. When
the XPath expression is interpreted, the set of namespace
declarations are those in scope on the rpc-error element,
including the default namespace.
error-message: Contains a string suitable for human display that
describes the error condition. This element will not be present
if no appropriate message is provided for a particular error
condition. This element SHOULD include an xml:lang attribute as
defined in [1] and discussed in [12].
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 in Appendix A
defines any mandatory error-info content for each error. After
any protocol-mandated content, a data model definition may mandate
that certain application-layer error information be included in
the error-info container. An implementation may include
additional elements to provide extended and/or implementation-
specific debugging information.
Appendix A enumerates the standard NETCONF errors.
Example:
An error is returned if an <rpc> element is received without a
message-id attribute. Note that only in this case is it
acceptable for the NETCONF peer to omit the message-id attribute
in the <rpc-reply> element.
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
</get-config>
</rpc>
<rpc-reply 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>
The following <rpc-reply> illustrates the case of returning
multiple <rpc-error> elements.
Note that the data models used in the examples in this section use
the <name> element to distinguish between multiple instances of
the <interface> element.
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<rpc-error>
<error-type>application</error-type>
<error-tag>invalid-value</error-tag>
<error-severity>error</error-severity>
<error-message xml:lang="en">
MTU value 25000 is not within range 256..9192
</error-message>
<error-info>
<top xmlns="http://example.com/schema/1.2/config">
<interface>
<name>Ethernet0/0</name>
<mtu>25000</mtu>
</interface>
</top>
</error-info>
</rpc-error>
<rpc-error>
<error-type>application</error-type>
<error-tag>invalid-value</error-tag>
<error-severity>error</error-severity>
<error-message xml:lang="en">
Invalid IP address for interface Ethernet1/0
</error-message>
<error-info>
<top xmlns="http://example.com/schema/1.2/config">
<interface xc:operation="replace">
<name>Ethernet1/0</name>
<address>
<name>1.4</name>
<prefix-length>24</prefix-length>
</address>
</interface>
</top>
</error-info>
</rpc-error>
</rpc-reply>
4.4. <ok> Element
The <ok> element is sent in <rpc-reply> messages if no errors or
warnings occurred during the processing of an <rpc> request. For
example:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
4.5. Pipelining
NETCONF <rpc> requests MUST be 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.
5. 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 8.1.
5.1. 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.
The capabilities in Sections 8.3 and 8.7 define the <candidate> and
<startup> configuration datastores, respectively.
5.2. Data Modeling
Data modeling and content issues are outside the scope of the NETCONF
protocol. An assumption is made that the device's data model is
well-known to the application and that both parties are aware of
issues such as the layout, containment, keying, lookup, replacement,
and management of the data, as well as any other constraints imposed
by the data model.
NETCONF carries configuration data inside the <config> element that
is specific to device's data model. The protocol treats the contents
of that element as opaque data. The device uses capabilities to
announce the set of data models that the device implements. The
capability definition details the operation and constraints imposed
by data model.
Devices and managers may support multiple data models, including both
standard and proprietary data models.
6. Subtree Filtering
6.1. Overview
XML subtree filtering is a mechanism that allows an application to
select particular XML subtrees to include in the <rpc-reply> for a
<get> or <get-config> operation. A small set of filters for
inclusion, simple content exact-match, and selection is provided,
which allows some useful, but also very limited, selection
mechanisms. The agent does not need to utilize any data-model-
specific semantics during processing, allowing for simple and
centralized implementation strategies.
Conceptually, a subtree filter is comprised of zero or more element
subtrees, which represent the filter selection criteria. At each
containment level within a subtree, the set of sibling nodes is
logically processed by the server to determine if its subtree and
path of elements to the root are included in the filter output.
All elements present in a particular subtree within a filter must
match associated nodes present in the server's conceptual data model.
XML namespaces may be specified (via 'xmlns' declarations) within the
filter data model. If they are, the declared namespace must first
exactly match a namespace supported by the server. Note that prefix
values for qualified namespaces are not relevant when comparing
filter elements to elements in the underlying data model. Only data
associated with a specified namespace will be included in the filter
output.
Each node specified in a subtree filter represents an inclusive
filter. Only associated nodes in underlying data model(s) within the
specified configuration datastore on the server are selected by the
filter. A node must exactly match the namespace and hierarchy of
elements given in the filter data, except that the filter absolute
path name is adjusted to start from the layer below <filter>.
Response messages contain only the subtrees selected by the filter.
Any selection criteria that were present in the request, within a
particular selected subtree, are also included in the response. Note
that some elements expressed in the filter as leaf nodes will be
expanded (i.e., subtrees included) in the filter output. Specific
data instances are not duplicated in the response in the event that
the request contains multiple filter subtree expressions that select
the same data.
6.2. Subtree Filter Components
A subtree filter is comprised of XML elements and their XML
attributes. There are five types of components that may be present
in a subtree filter:
o Namespace Selection
o Attribute Match Expressions
o Containment Nodes
o Selection Nodes
o Content Match Nodes
6.2.1. Namespace Selection
If namespaces are used, then the filter output will only include
elements from the specified namespace. A namespace is considered to
match (for filter purposes) if the content of the 'xmlns' attributes
are the same in the filter and the underlying data model. Note that
namespace selection cannot be used by itself. At least one element
must be specified in the filter any elements to be included in the
filter output.
Example:
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config"/>
</filter>
In this example, the <top> element is a selection node, and only this
node and any child nodes (from the underlying data model) in the
'http://example.com/schema/1.2/config' namespace will be included in
the filter output.
6.2.2. Attribute Match Expressions
An attribute that appears in a subtree filter is part of an
"attribute match expression". Any number of (unqualified or
qualified) XML attributes may be present in any type of filter node.
In addition to the selection criteria normally applicable to that
node, the selected data must have matching values for every attribute
specified in the node. If an element is not defined to include a
specified attribute, then it is not selected in the filter output.
Example:
<filter type="subtree">
<t:top xmlns:t="http://example.com/schema/1.2/config">
<t:interfaces>
<t:interface t:ifName="eth0"/>
</t:interfaces>
</t:top>
</filter>
In this example, the <top>, <interfaces>, and <interface> elements
are containment nodes, and 'ifName' is an attribute match expression.
Only 'interface' nodes in the 'http://example.com/schema/1.2/config'
namespace that have an 'ifName' attribute with the value 'eth0' and
occur within 'interfaces' nodes within 'top' nodes will be included
in the filter output.
6.2.3. Containment Nodes
Nodes that contain child elements within a subtree filter are called
"containment nodes". Each child element can be any type of node,
including another containment node. For each containment node
specified in a subtree filter, all data model instances that exactly
match the specified namespaces, element hierarchy, and any attribute
match expressions are included in the filter output.
Example:
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users/>
</top>
</filter>
In this example, the <top> element is a containment node.
6.2.4. Selection Nodes
An empty leaf node within a filter is called a "selection node", and
it represents an "explicit selection" filter on the underlying data
model. Presence of any selection nodes within a set of sibling nodes
will cause the filter to select the specified subtree(s) and suppress
automatic selection of the entire set of sibling nodes in the
underlying data model. For filtering purposes, an empty leaf node
can be declared either with an empty tag (e.g., <foo/>) or with
explicit start and end tags (e.g., <foo> </foo>). Any whitespace
characters are ignored in this form.
Example:
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users/>
</top>
</filter>
In this example, the <top> element is a containment node, and the
<users> element is a selection node. Only 'users' nodes in the
'http://example.com/schema/1.2/config' namespace that occur within a
'top' element that is the root of the configuration datastore will be
included in the filter output.
6.2.5. Content Match Nodes
A leaf node that contains simple content is called a "content match
node". It is used to select some or all of its sibling nodes for
filter output, and it represents an exact-match filter on the leaf
node element content. The following constraints apply to content
match nodes:
o A content match node must not contain nested elements (i.e., must
resolve to a simpleType in the XML Schema Definition (XSD)).
o Multiple content match nodes (i.e., sibling nodes) are logically
combined in an "AND" expression.
o Filtering of mixed content is not supported.
o Filtering of list content is not supported.
o Filtering of whitespace-only content is not supported.
o A content match node must contain non-whitespace characters. An
empty element (e.g., <foo></foo>) will be interpreted as a
selection node (e.g., <foo/>).
o Leading and trailing whitespace characters are ignored, but any
whitespace characters within a block of text characters are not
ignored or modified.
If all specified sibling content match nodes in a subtree filter
expression are 'true', then the filter output nodes are selected in
the following manner:
o Each content match node in the sibling set is included in the
filter output.
o If any containment nodes are present in the sibling set, then they
are processed further and included if any nested filter criteria
are also met.
o If any selection nodes are present in the sibling set, then all of
them are included in the filter output.
o Otherwise (i.e., there are no selection or containment nodes in
the filter sibling set), all the nodes defined at this level in
the underlying data model (and their subtrees, if any) are
returned in the filter output.
If any of the sibling content match node tests are 'false', then no
further filter processing is performed on that sibling set, and none
of the sibling subtrees are selected by the filter, including the
content match node(s).
Example:
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>fred</name>
</user>
</users>
</top>
</filter>
In this example, the <users> and <user> nodes are both containment
nodes, and <name> is a content match node. Since no sibling nodes of
<name> are specified (and therefore no containment or selection
nodes), all of the sibling nodes of <name> are returned in the filter
output. Only 'user' nodes in the
'http://example.com/schema/1.2/config' namespace that match the
element hierarchy and for which the <name> element is equal to 'fred'
will be included in the filter output.
6.3. Subtree Filter Processing
The filter output (the set of selected nodes) is initially empty.
Each subtree filter can contain one or more data model fragments,
which represent portions of the data model that should be selected
(with all child nodes) in the filter output.
Each subtree data fragment is compared by the server to the internal
data models supported by the server. If the entire subtree data-
fragment filter (starting from the root to the innermost element
specified in the filter) exactly matches a corresponding portion of
the supported data model, then that node and all its children are
included in the result data.
The server processes all nodes with the same parent node (sibling
set) together, starting from the root to the leaf nodes. The root
elements in the filter are considered in the same sibling set
(assuming they are in the same namespace), even though they do not
have a common parent.
For each sibling set, the server determines which nodes are included
(or potentially included) in the filter output, and which sibling
subtrees are excluded (pruned) from the filter output. The server
first determines which types of nodes are present in the sibling set
and processes the nodes according to the rules for their type. If
any nodes in the sibling set are selected, then the process is
recursively applied to the sibling sets of each selected node. The
algorithm continues until all sibling sets in all subtrees specified
in the filter have been processed.
6.4. Subtree Filtering Examples
6.4.1. No Filter
Leaving out the filter on the get operation returns the entire data
model.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get/>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<!-- ... entire set of data returned ... -->
</data>
</rpc-reply>
6.4.2. Empty Filter
An empty filter will select nothing because no content match or
selection nodes are present. This is not an error. The filter type
attribute used in these examples is discussed further in Section 7.1.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get>
<filter type="subtree">
</filter>
</get>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
</data>
</rpc-reply>
6.4.3. Select the Entire <users> Subtree
The filter in this example contains one selection node (<users>), so
just that subtree is selected by the filter. This example represents
the fully-populated <users> data model in most of the filter examples
that follow. In a real data model, the <company-info> would not
likely be returned with the list of users for a particular host or
network.
NOTE: The filtering and configuration examples used in this document
appear in the namespace "http://example.com/schema/1.2/config". The
root element of this namespace is <top>. The <top> element and its
descendents represent an example configuration data model only.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users/>
</top>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>root</name>
<type>superuser</type>
<full-name>Charlie Root</full-name>
<company-info>
<dept>1</dept>
<id>1</id>
</company-info>
</user>
<user>
<name>fred</name>
<type>admin</type>
<full-name>Fred Flintstone</full-name>
<company-info>
<dept>2</dept>
<id>2</id>
</company-info>
</user>
<user>
<name>barney</name>
<type>admin</type>
<full-name>Barney Rubble</full-name>
<company-info>
<dept>2</dept>
<id>3</id>
</company-info>
</user>
</users>
</top>
</data>
</rpc-reply>
The following filter request would have produced the same result, but
only because the container <users> defines one child element
(<user>).
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user/>
</users>
</top>
</filter>
</get-config>
</rpc>
6.4.4. Select All <name> Elements within the <users> Subtree
This filter contains two containment nodes (<users>, <user>) and one
selector node (<name>). All instances of the <name> element in the
same sibling set are selected in the filter output. The manager may
need to know that <name> is used as an instance identifier in this
particular data structure, but the server does not need to know that
meta-data in order to process the request.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name/>
</user>
</users>
</top>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>root</name>
</user>
<user>
<name>fred</name>
</user>
<user>
<name>barney</name>
</user>
</users>
</top>
</data>
</rpc-reply>
6.4.5. One Specific <user> Entry
This filter contains two containment nodes (<users>, <user>) and one
content match node (<name>). All instances of the sibling set
containing <name> for which the value of <name> equals "fred" are
selected in the filter output.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>fred</name>
</user>
</users>
</top>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>fred</name>
<type>admin</type>
<full-name>Fred Flintstone</full-name>
<company-info>
<dept>2</dept>
<id>2</id>
</company-info>
</user>
</users>
</top>
</data>
</rpc-reply>
6.4.6. Specific Elements from a Specific <user> Entry
This filter contains two containment nodes (<users>, <user>), one
content match node (<name>), and two selector nodes (<type>,
<full-name>). All instances of the <type> and <full-name> elements
in the same sibling set containing <name> for which the value of
<name> equals "fred" are selected in the filter output. The
<company-info> element is not included because the sibling set
contains selection nodes.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>fred</name>
<type/>
<full-name/>
</user>
</users>
</top>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>fred</name>
<type>admin</type>
<full-name>Fred Flintstone</full-name>
</user>
</users>
</top>
</data>
</rpc-reply>
6.4.7. Multiple Subtrees
This filter contains three subtrees (name=root, fred, barney).
The "root" subtree filter contains two containment nodes (<users>,
<user>), one content match node (<name>), and one selector node
(<company-info>). The subtree selection criteria is met, and just
the company-info subtree for "root" is selected in the filter output.
The "fred" subtree filter contains three containment nodes (<users>,
<user>, <company-info>), one content match node (<name>), and one
selector node (<id>). The subtree selection criteria is met, and
just the <id> element within the company-info subtree for "fred" is
selected in the filter output.
The "barney" subtree filter contains three containment nodes
(<users>, <user>, <company-info>), two content match nodes (<name>,
<type>), and one selector node (<dept>). The subtree selection
criteria is not met because user "barney" is not a "superuser", and
the entire subtree for "barney" (including its parent <user> entry)
is excluded from the filter output.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>root</name>
<company-info/>
</user>
<user>
<name>fred</name>
<company-info>
<id/>
</company-info>
</user>
<user>
<name>barney</name>
<type>superuser</type>
<company-info>
<dept/>
</company-info>
</user>
</users>
</top>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>root</name>
<company-info>
<dept>1</dept>
<id>1</id>
</company-info>
</user>
<user>
<name>fred</name>
<company-info>
<id>2</id>
</company-info>
</user>
</users>
</top>
</data>
</rpc-reply>
6.4.8. Elements with Attribute Naming
In this example, the filter contains one containment node
(<interfaces>), one attribute match expression (ifName), and one
selector node (<interface>). All instances of the <interface>
subtree that have an ifName attribute equal to "eth0" are selected in
the filter output. The filter data elements and attributes must be
qualified because the ifName attribute will not be considered part of
the 'schema/1.2' namespace if it is unqualified.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get>
<filter type="subtree">
<t:top xmlns:t="http://example.com/schema/1.2/stats">
<t:interfaces>
<t:interface t:ifName="eth0"/>
</t:interfaces>
</t:top>
</filter>
</get>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<t:top xmlns:t="http://example.com/schema/1.2/stats">
<t:interfaces>
<t:interface t:ifName="eth0">
<t:ifInOctets>45621</t:ifInOctets>
<t:ifOutOctets>774344</t:ifOutOctets>
</t:interface>
</t:interfaces>
</t:top>
</data>
</rpc-reply>
If ifName were a child node instead of an attribute, then the
following request would produce similar results.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/stats">
<interfaces>
<interface>
<ifName>eth0</ifName>
</interface>
</interfaces>
</top>
</filter>
</get>
</rpc>
7. 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
o get-config
o edit-config
o copy-config
o delete-config
o lock
o unlock
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.
7.1. <get-config>
Description:
Retrieve all or part of a specified configuration.
Parameters:
source:
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 element is unspecified, the
entire configuration is returned.
The filter element may optionally contain a "type" attribute.
This attribute indicates the type of filtering syntax used
within the filter element. The default filtering mechanism in
NETCONF is referred to as subtree filtering and is described in
Section 6. The value "subtree" explicitly identifies this type
of filtering.
If the NETCONF peer supports the :xpath capability
(Section 8.9), the value "xpath" may be used to indicate that
the select attribute on the filter element contains an XPath
expression.
Positive Response:
If the device can satisfy the request, the server sends an
<rpc-reply> element containing a <data> 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: To retrieve the entire <users> subtree:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/config">
<users/>
</top>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/config">
<users>
<user>
<name>root</name>
<type>superuser</type>
<full-name>Charlie Root</full-name>
<company-info>
<dept>1</dept>
<id>1</id>
</company-info>
</user>
<!-- additional <user> elements appear here... -->
</users>
</top>
</data>
</rpc-reply>
If the configuration is available in multiple formats, such as XML
and text, an XML namespace can be used to specify which format is
desired. In the following example, the client uses a specific
element (<config-text>) in a specific namespace to indicate to the
server the desire to receive the configuration in an alternative
format. The server may support any number of distinct formats or
views into the configuration data, with the client using the <filter>
parameter to select between them.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<!-- request a text version of the configuration -->
<config-text xmlns="http://example.com/text/1.2/config"/>
</filter>
</get-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<config-text xmlns="http://example.com/text/1.2/config">
<!-- configuration text... -->
</config-text>
</data>
</rpc-reply>
Section 6 contains additional examples of subtree filtering.
7.2. <edit-config>
Description:
The <edit-config> operation loads 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 will be created. If a
NETCONF peer supports the :url capability (Section 8.8), the <url>
element can appear instead of the <config> parameter and should
identify a local configuration file.
The device analyzes the source and target configurations and
performs the requested changes. The target configuration is not
necessarily replaced, as with the <copy-config> message. Instead,
the target configuration is changed in accordance with the
source's data and requested operations.
Attributes:
operation:
Elements in the <config> subtree may contain an "operation"
attribute. The attribute identifies the point in the
configuration to perform the operation and MAY appear on
multiple elements throughout the <config> subtree.
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. This is the default
behavior.
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:
Name of the configuration datastore being edited, such as
<running/> or <candidate/>.
default-operation:
Selects the default operation (as described in the "operation"
attribute) for this <edit-config> request. The default value
for the default-operation parameter is "merge".
The default-operation parameter is optional, but if provided,
it must have one of the following values:
merge: The configuration data in the <config> parameter is
merged with the configuration at the corresponding level in
the target datastore. This is the default behavior.
replace: The configuration data in the <config> parameter
completely replaces the configuration in the target
datastore. This is useful for loading previously saved
configuration data.
none: The target datastore is unaffected by the configuration
in the <config> parameter, unless and until the incoming
configuration data uses the "operation" attribute to request
a different operation. If the configuration in the <config>
parameter contains data for which there is not a
corresponding level in the target datastore, an <rpc-error>
is returned with an <error-tag> value of data-missing.
Using "none" allows operations like "delete" to avoid
unintentionally creating the parent hierarchy of the element
to be deleted.
test-option:
The test-option element may be specified only if the device
advertises the :validate capability (Section 8.6).
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.
continue-on-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 server
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 server to support the :rollback-on-error capability
described in Section 8.5.
config:
A hierarchy of configuration data as defined by one of the
device's data models. The contents MUST be placed in an
appropriate namespace, to allow the device to detect the
appropriate data model, and the contents MUST follow the
constraints of that data model, as defined by its capability
definition. Capabilities are discussed in Section 8.
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:
The <edit-config> examples in this section utilize a simple data
model, in which multiple instances of the 'interface' element may
be present, and an instance is distinguished by the 'name' element
within each 'interface' element.
Set the MTU to 1500 on an interface named "Ethernet0/0" in the
running configuration:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<top xmlns="http://example.com/schema/1.2/config">
<interface>
<name>Ethernet0/0</name>
<mtu>1500</mtu>
</interface>
</top>
</config>
</edit-config>
</rpc>
<rpc-reply message-id="101"
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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<top xmlns="http://example.com/schema/1.2/config">
<interface xc:operation="replace">
<name>Ethernet0/0</name>
<mtu>1500</mtu>
<address>
<name>192.0.2.4</name>
<prefix-length>24</prefix-length>
</address>
</interface>
</top>
</config>
</edit-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Delete the configuration for an interface named "Ethernet0/0" from
the running configuration:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<default-operation>none</default-operation>
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<top xmlns="http://example.com/schema/1.2/config">
<interface xc:operation="delete">
<name>Ethernet0/0</name>
</interface>
</top>
</config>
</edit-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Delete interface 192.0.2.4 from an OSPF area (other interfaces
configured in the same area are unaffected):
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<default-operation>none</default-operation>
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<top xmlns="http://example.com/schema/1.2/config">
<protocols>
<ospf>
<area>
<name>0.0.0.0</name>
<interfaces>
<interface xc:operation="delete">
<name>192.0.2.4</name>
</interface>
</interfaces>
</area>
</ospf>
</protocols>
</top>
</config>
</edit-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
7.3. <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, if allowed.
If a NETCONF peer supports the :url capability (Section 8.8), the
<url> element can appear as the <source> or <target> parameter.
Even if it advertises the :writable-running capability, 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, where
both the <source> and <target> parameters use the <url> element.
If the source and target parameters identify the same URL or
configuration datastore, an error MUST be returned with an error-
tag containing invalid-value.
Parameters:
target:
Name of the configuration datastore to use as the destination
of the copy operation.
source:
Name of the configuration datastore to use as the source of the
copy operation or the <config> element containing the
configuration subtree to copy.
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:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<copy-config>
<target>
<running/>
</target>
<source>
<url>https://user@example.com:passphrase/cfg/new.txt</url>
</source>
</copy-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
7.4. <delete-config>
Description:
Delete a configuration datastore. The <running> configuration
datastore cannot be deleted.
If a NETCONF peer supports the :url capability (Section 8.8), the
<url> element can appear as the <target> parameter.
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:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<delete-config>
<target>
<startup/>
</target>
</delete-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
7.5. <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 (e.g., SNMP and command
line interface (CLI) 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 failure of the underlying transport, or
simple inactivity timeout. This criteria is dependent on the
implementation and the underlying transport.
The lock operation takes a mandatory parameter, target. The
target parameter names the configuration that 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 NETCONF 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 MUST not be granted if either of the following conditions
is true:
* A lock is already held by any NETCONF session or another
entity.
* The target configuration is <candidate>, it has already been
modified, and these changes have not been committed or rolled
back.
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.
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.
If the lock is already held, the <error-tag> element will be
'lock-denied' and the <error-info> element will include the
<session-id> of the lock owner. 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.
Example:
The following example shows a successful acquisition of a lock.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<lock>
<target>
<running/>
</target>
</lock>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/> <!-- lock succeeded -->
</rpc-reply>
Example:
The following example shows a failed attempt to acquire a lock
when the lock is already in use.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<lock>
<target>
<running/>
</target>
</lock>
</rpc>
<rpc-reply message-id="101"
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>
<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>
7.6. <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
* 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.
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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<unlock>
<target>
<running/>
</target>
</unlock>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
7.7. <get>
Description:
Retrieve running configuration and device state information.
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.
The filter element may optionally contain a 'type' attribute.
This attribute indicates the type of filtering syntax used
within the filter element. The default filtering mechanism in
NETCONF is referred to as subtree filtering and is described in
Section 6. The value 'subtree' explicitly identifies this type
of filtering.
If the NETCONF peer supports the :xpath capability
(Section 8.9), the value "xpath" may be used to indicate that
the select attribute of the filter element contains an XPath
expression.
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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get>
<filter type="subtree">
<top xmlns="http://example.com/schema/1.2/stats">
<interfaces>
<interface>
<ifName>eth0</ifName>
</interface>
</interfaces>
</top>
</filter>
</get>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<top xmlns="http://example.com/schema/1.2/stats">
<interfaces>
<interface>
<ifName>eth0</ifName>
<ifInOctets>45621</ifInOctets>
<ifOutOctets>774344</ifOutOctets>
</interface>
</interfaces>
</top>
</data>
</rpc-reply>
7.8. <close-session>
Description:
Request graceful termination of a NETCONF session.
When a NETCONF server receives a <close-session> request, it will
gracefully close the session. The server will release any locks
and resources associated with the session and gracefully close any
associated connections. Any NETCONF requests received after a
<close-session> request will be ignored.
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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<close-session/>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
7.9. <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.
If a NETCONF server receives a <kill-session> request while
processing a confirmed commit (Section 8.4), it must restore the
configuration to its state before the confirmed commit was issued.
Otherwise, the <kill-session> operation does not roll back
configuration or other device state modifications made by the
entity holding the lock.
Parameters:
session-id:
Session identifier of the NETCONF session to be terminated. If
this value is equal to the current session ID, an
'invalid-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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<kill-session>
<session-id>4</session-id>
</kill-session>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
8. 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 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 C. Future capability definitions may be published as
standards by standards bodies or published as proprietary extensions.
A NETCONF capability is identified with a URI. The base capabilities
are defined using URNs following the method described in RFC 3553
[6]. Capabilities defined in this document have the following
format:
urn:ietf:params:netconf:capability:{name}:1.0
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:netconf:capability:foo:1.0" and be called ":foo".
The shorthand form MUST NOT be used inside the protocol.
8.1. Capabilities Exchange
Capabilities are advertised in messages sent by each peer during
session establishment. When the NETCONF session is opened, each peer
(both client and server) MUST send a <hello> element containing a
list of that peer's capabilities. Each peer MUST send at least the
base NETCONF capability, "urn:ietf:params:netconf:base:1.0".
A server sending the <hello> element MUST include a <session-id>
element containing the session ID for this NETCONF session. A client
sending the <hello> element MUST NOT include a <session-id> element.
A server receiving a <session-id> element MUST NOT continue the
NETCONF session. Similarly, a client that does not receive a
<session-id> element in the server's <hello> message MUST NOT
continue the NETCONF session. In both cases, the underlying
transport should be closed.
In the following example, a server advertises the base NETCONF
capability, one NETCONF capability defined in the base NETCONF
document, and one implementation-specific capability.
<hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<capabilities>
<capability>
urn:ietf:params:netconf:base:1.0
</capability>
<capability>
urn:ietf:params:netconf:capability:startup:1.0
</capability>
<capability>
http://example.net/router/2.3/myfeature
</capability>
</capabilities>
<session-id>4</session-id>
</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.
8.2. Writable-Running Capability
8.2.1. Description
The :writable-running capability indicates that the device supports
direct writes to the <running> configuration datastore. In other
words, the device supports edit-config and copy-config operations
where the <running> configuration is the target.
8.2.2. Dependencies
None.
8.2.3. Capability Identifier
The :writable-running capability is identified by the following
capability string:
urn:ietf:params:netconf:capability:writable-running:1.0
8.2.4. New Operations
None.
8.2.5. Modifications to Existing Operations
8.2.5.1. <edit-config>
The :writable-running capability modifies the <edit-config> operation
to accept the <running> element as a <target>.
8.2.5.2. <copy-config>
The :writable-running capability modifies the <copy-config> operation
to accept the <running> element as a <target>.
8.3. Candidate Configuration Capability
8.3.1. Description
The candidate configuration capability, :candidate, indicates that
the device supports a candidate configuration datastore, which is
used to hold configuration data that can be 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 and 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 <commit> operation effectively sets the running configuration to
the current contents of the candidate configuration. While it could
be modeled as a simple copy, it is done as a distinct operation for a
number of reasons. In keeping high-level concepts as first class
operations, we allow developers to see more clearly both what the
client is requesting and what the server must perform. This keeps
the intentions more obvious, the special cases less complex, and the
interactions between operations more straightforward. For example,
the :confirmed-commit capability (Section 8.4) would make no sense as
a "copy confirmed" operation.
The candidate configuration may be shared among multiple sessions.
Unless a client has specific information that the candidate
configuration is not shared, 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 uncommitted changes to the candidate
configuration by executing the <discard-changes> operation. This
operation reverts the contents of the candidate configuration to the
contents of the running configuration.
8.3.2. Dependencies
None.
8.3.3. Capability Identifier
The :candidate capability is identified by the following capability
string:
urn:ietf:params:netconf:capability:candidate:1.0
8.3.4. New Operations
8.3.4.1. <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 device is unable to commit all of the changes in the
candidate configuration datastore, then the running
configuration MUST remain unchanged. If the device does
succeed in committing, the running configuration MUST be
updated with the contents of 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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<commit/>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
8.3.4.2. <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 running configuration.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<discard-changes/>
</rpc>
This operation discards any uncommitted changes by resetting the
candidate configuration with the content of the running
configuration.
8.3.5. Modifications to Existing Operations
8.3.5.1. <get-config>, <edit-config>, <copy-config>, and <validate>
The candidate configuration can be used as a source or target of any
<get-config>, <edit-config>, <copy-config>, or <validate> operation
as a <source> or <target> parameter. The <candidate> element is used
to indicate the candidate configuration:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config> <!-- any NETCONF operation -->
<source>
<candidate/>
</source>
</get-config>
</rpc>
8.3.5.2. <lock> and <unlock>
The candidate configuration can be locked using the <lock> operation
with the <candidate> element as the <target> parameter:
<rpc message-id="101"
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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<unlock>
<target>
<candidate/>
</target>
</unlock>
</rpc>
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.
8.4. Confirmed Commit Capability
8.4.1. Description
The :confirmed-commit capability indicates that the server will
support the <confirmed> and <confirm-timeout> parameters for the
<commit> protocol operation. See Section 8.3 for further details on
the <commit> operation.
A confirmed commit operation MUST be reverted if a follow-up commit
(called the "confirming commit") is not issued within 600 seconds (10
minutes). The timeout period can be adjusted with the
<confirm-timeout> element. The confirming commit can itself include
a <confirmed> parameter.
If the session issuing the confirmed commit is terminated for any
reason before the confirm timeout expires, the server MUST restore
the configuration to its state before the confirmed commit was
issued.
If the device reboots for any reason before the confirm timeout
expires, the server MUST restore the configuration to its state
before the confirmed commit was issued.
If a confirming commit is not issued, the device will revert its
configuration to the state prior to the issuance of the confirmed
commit. Note that any commit operation, including a commit which
introduces additional changes to the configuration, will serve as a
confirming commit. Thus to cancel a confirmed commit and revert
changes without waiting for the confirm timeout to expire, the
manager can explicitly restore the configuration to its state before
the confirmed commit was issued.
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, the lock is 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 should also be used.
8.4.2. Dependencies
The :confirmed-commit capability is only relevant if the :candidate
capability is also supported.
8.4.3. Capability Identifier
The :confirmed-commit capability is identified by the following
capability string:
urn:ietf:params:netconf:capability:confirmed-commit:1.0
8.4.4. New Operations
None.
8.4.5. Modifications to Existing Operations
8.4.5.1. <commit>
The :confirmed-commit capability allows 2 additional parameters to
the <commit> operation.
Parameters:
confirmed:
Perform a confirmed commit operation.
confirm-timeout:
Timeout period for confirmed commit, in seconds. If
unspecified, the confirm timeout defaults to 600 seconds.
Example:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<commit>
<confirmed/>
<confirm-timeout>120</confirm-timeout>
</commit>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
8.5. Rollback on Error Capability
8.5.1. Description
This capability indicates that the server 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, the lock is 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 also be used.
8.5.2. Dependencies
None
8.5.3. Capability Identifier
The :rollback-on-error capability is identified by the following
capability string:
urn:ietf:params:netconf:capability:rollback-on-error:1.0
8.5.4. New Operations
None.
8.5.5. Modifications to Existing Operations
8.5.5.1. <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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<error-option>rollback-on-error</error-option>
<config>
<top xmlns="http://example.com/schema/1.2/config">
<interface>
<name>Ethernet0/0</name>
<mtu>100000</mtu>
</interface>
</top>
</config>
</edit-config>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
8.6. Validate Capability
8.6.1. 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 test-option parameter to the
<edit-config> operation and, when it is provided, checks at least for
syntax errors.
8.6.2. Dependencies
None.
8.6.3. Capability Identifier
The :validate capability is identified by the following capability
string:
urn:ietf:params:netconf:capability:validate:1.0
8.6.4. New Operations
8.6.4.1. <validate>
Description:
This protocol operation validates the contents of the specified
configuration.
Parameters:
source:
Name of the configuration datastore being validated, such as
<candidate> or the <config> element containing the
configuration subtree to validate.
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.
A validate operation can fail for any of the following reasons:
+ Syntax errors
+ Missing parameters
+ References to undefined configuration data
Example:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<validate>
<source>
<candidate/>
</source>
</validate>
</rpc>
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
8.7. Distinct Startup Capability
8.7.1. Description
The device supports separate running and startup configuration
datastores. Operations that 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.
8.7.2. Dependencies
None.
8.7.3. Capability Identifier
The :startup capability is identified by the following capability
string:
urn:ietf:params:netconf:capability:startup:1.0
8.7.4. New Operations
None.
8.7.5. Modifications to Existing Operations
8.7.5.1. General
The :startup capability adds the <startup/> configuration datastore
to arguments of several NETCONF operations. The server MUST support
the following additional values:
+--------------------+--------------------------+-------------------+
| Operation | Parameters | Notes |
+--------------------+--------------------------+-------------------+
| <get-config> | <source> | |
| | | |
| <copy-config> | <source> <target> | |
| | | |
| <lock> | <target> | |
| | | |
| <unlock> | <target> | |
| | | |
| <validate> | <source> | If :validate is |
| | | advertised |
+--------------------+--------------------------+-------------------+
To save the startup configuration, use the copy-config operation to
copy the <running> configuration datastore to the <startup>
configuration datastore.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<copy-config>
<target>
<startup/>
</target>
<source>
<running/>
</source>
</copy-config>
</rpc>
Notes:
The parameters are in the wrong order. The XSD and the example on page 40 are correct.
8.8. URL Capability
8.8.1. 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 URL schemes supported.
8.8.2. Dependencies
None.
8.8.3. Capability Identifier
The :url capability is identified by the following capability string:
urn:ietf:params:netconf:capability:url:1.0?scheme={name,...}
The :url capability URI MUST contain a "scheme" argument assigned a
comma-separated list of scheme names indicating which schemes the
NETCONF peer supports. For example:
urn:ietf:params:netconf:capability:url:1.0?scheme=http,ftp,file
8.8.4. New Operations
None.
8.8.5. Modifications to Existing Operations
8.8.5.1. <edit-config>
The :url capability modifies the <edit-config> operation to accept
the <url> element as an alternative to the <config> parameter. If
the <url> element is specified, then it should identify a local
configuration file.
8.8.5.2. <copy-config>
The :url capability modifies the <copy-config> operation to accept
the <url> element as the value of the <source> and the <target>
parameters.
8.8.5.3. <delete-config>
The :url capability modifies the <delete-config> operation to accept
the <url> element as the value of the <target> parameters. If this
parameter contains a URL, then it should identify a local
configuration file.
8.8.5.4. <validate>
The :url capability modifies the <validate> operation to accept the
<url> element as the value of the <source> parameter.
8.9. XPath Capability
8.9.1. Description
The XPath capability indicates that the NETCONF peer supports the use
of XPath expressions in the <filter> element. XPath is described in
[2].
The XPath expression must return a node-set.
The XPath expression is evaluated in a context where the context node
is the root node, and the set of namespace declarations are those in
scope on the filter element, including the default namespace.
8.9.2. Dependencies
None.
8.9.3. Capability Identifier
The :xpath capability is identified by the following capability
string:
urn:ietf:params:netconf:capability:xpath:1.0
8.9.4. New Operations
None.
8.9.5. Modifications to Existing Operations
8.9.5.1. <get-config> and <get>
The :xpath capability modifies the <get> and <get-config> operations
to accept the value "xpath" in the type attribute of the filter
element. When the type attribute is set to "xpath", a select
attribute MUST be present on the filter element. The select
attribute will be treated as an XPath expression and used to filter
the returned data. The filter element itself MUST be empty in this
case.
For example:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<!-- get the user named fred -->
<filter type="xpath" select="top/users/user[name='fred']"/>
</get-config>
</rpc>
9. Security Considerations
This document does not specify an authorization scheme, as such a
scheme should be tied to a meta-data model or a data model.
Implementors SHOULD provide a comprehensive authorization scheme with
NETCONF.
Authorization of individual users via the NETCONF server may or may
not map 1:1 to other interfaces. First, the data models may be
incompatible. Second, it may be desirable to authorize based on
mechanisms available in the transport protocol layer (TELNET, SSH,
etc).
In addition, operations on configurations may have unintended
consequences if those operations are also not guarded by the global
lock on the files or objects being operated upon. For instance, a
partially complete access list could be committed from a candidate
configuration unbeknownst to the owner of the lock of the candidate
configuration, leading to either an insecure or inaccessible device
if the lock on the candidate configuration does not also apply to the
<copy-config> operation when applied to it.
Configuration information is by its very nature sensitive. Its
transmission in the clear and without integrity checking leaves
devices open to classic eavesdropping attacks. Configuration
information often 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
confidentiality and authentication. It is anticipated that the
underlying protocol (SSH, BEEP, etc) will provide for both
confidentiality 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 re-authenticate, 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, a simple "access 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
operations 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, whereas <edit-config>
is. Such global operations MUST disallow the changing of information
that an individual does not have authorization to perform. For
example, if a user A is not allowed to configure an IP address on an
interface but user B has configured an IP address on an interface in
the <candidate> configuration, user A must not be allowed to commit
the <candidate> configuration.
Similarly, just because someone says "go write a configuration
through the URL capability at a particular place", this does not mean
that an element should do it without proper authorization.
The <lock> operation will demonstrate that 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 principal 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 device's native
user interface. These two mechanisms suffer from a race condition
that may be ameliorated by removing the offending user from an AAA
server. However, such a solution is not useful in all deployment
scenarios, such as those where SSH public/private key pairs are used.
10. IANA Considerations
10.1. NETCONF XML Namespace
This document registers a URI for the NETCONF XML namespace in the
IETF XML registry [7].
Following the format in RFC 3688, IANA has made the following
registration.
URI: urn:ietf:params:xml:ns:netconf:base:1.0
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
10.2. NETCONF XML Schema
This document registers a URI for the NETCONF XML schema in the IETF
XML registry [7].
Following the format in RFC 3688, IANA has made the following
registration.
URI: urn:ietf:params:xml:schema:netconf
Registrant Contact: The IESG.
XML: Appendix B of this document.
10.3. NETCONF Capability URNs
This document creates a registry that allocates NETCONF capability
identifiers. Additions to the registry require IETF Standards
Action.
The initial content of the registry contains the capability URNs
defined in Section 8.
Following the guidelines in RFC 3553 [6], IANA assigned a NETCONF
sub-namespace as follows:
Registry name: netconf
Specification: Section 8 of this document.
Repository: The following table.
+--------------------+----------------------------------------------+
| Index | Capability Identifier |
+--------------------+----------------------------------------------+
| :writable-running | urn:ietf:params:netconf:capability:writable- |
| | running:1.0 |
| | |
| :candidate | urn:ietf:params:netconf:capability:candidate |
| | :1.0 |
| | |
| :confirmed-commit | urn:ietf:params:netconf:capability:confirmed |
| | -commit:1.0 |
| | |
| :rollback-on-error | urn:ietf:params:netconf:capability:rollback- |
| | on-error:1.0 |
| | |
| :validate | urn:ietf:params:netconf:capability:validate: |
| | 1.0 |
| | |
| :startup | urn:ietf:params:netconf:capability:startup:1 |
| | .0 |
| | |
| :url | urn:ietf:params:netconf:capability:url:1.0 |
| | |
| :xpath | urn:ietf:params:netconf:capability:xpath:1.0 |
+--------------------+----------------------------------------------+
Index value: The capability name.
11. Authors and Acknowledgements
This document was written by:
Andy Bierman
Ken Crozier, Cisco Systems
Rob Enns, Juniper Networks
Ted Goddard, IceSoft
Eliot Lear, Cisco Systems
Phil Shafer, Juniper Networks
Steve Waldbusser
Margaret Wasserman, ThingMagic
The authors would like to acknowledge the members of the NETCONF
working group. In particular, we would like to thank Wes Hardaker
for his persistance and patience in assisting us with security
considerations. We would also like to thank Randy Presuhn, Sharon
Chisholm, Juergen Schoenwalder, Glenn Waters, David Perkins, Weijing
Chen, Simon Leinen, Keith Allen, and Dave Harrington for all of their
valuable advice.
12. References
12.1. Normative References
[1] Sperberg-McQueen, C., Paoli, J., Maler, E., and T. Bray,
"Extensible Markup Language (XML) 1.0 (Second Edition)", World
Wide Web Consortium, http://www.w3.org/TR/2000/REC-xml-20001006,
October 2000.
[2] Clark, J. and S. DeRose, "XML Path Language (XPath) Version
1.0", World Wide Web Consortium Recommendation,
http://www.w3.org/TR/1999/REC-xpath-19991116, November 1999.
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[4] Wasserman, M. and T. Goddard, "Using the NETCONF Configuration
Protocol over Secure SHell (SSH)", RFC 4742, December 2006.
[5] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
January 2005.
[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.
[7] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
12.2. Informative References
[8] Clark, J., "XSL Transformations (XSLT) Version 1.0", World Wide
Web Consortium Recommendation, http://www.w3.org/TR/1999/REC-
xslt-19991116, November 1999.
[9] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS)
Protocol Version 1.1", RFC 4346, April 2006.
[10] Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Protocol
Architecture", RFC 4251, January 2006.
[11] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote
Authentication Dial In User Service (RADIUS)", RFC 2865,
June 2000.
[12] 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.
Appendix A. NETCONF Error List
Tag: in-use
Error-type: protocol, application
Severity: error
Error-info: none
Description: The request requires a resource that already in use.
Tag: invalid-value
Error-type: protocol, application
Severity: error
Error-info: none
Description: The request specifies an unacceptable value for one
or more parameters.
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
Error-type: rpc, protocol, application
Severity: error
Error-info: <bad-element> : name of the unexpected element
Description: An unexpected element is present.
Tag: unknown-namespace
Error-type: rpc, protocol, application
Severity: error
Error-info: <bad-element> : name of the element that contains
the unexpected namespace
<bad-namespace> : name of the unexpected namespace
Description: An unexpected namespace is present.
Tag: access-denied
Error-type: rpc, protocol, application
Severity: error
Error-info: none
Description: Access to the requested RPC, protocol operation,
or 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 that
already exists.
Tag: data-missing
Error-type: application
Severity: error
Error-info: none
Description: Request could not be completed because the relevant
data model content does not exist. For example,
a 'replace' or 'delete' operation was attempted on
data that 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 server. The error-info container is used
to identify which portions of the application
data model content for which the requested operation
has succeeded (<ok-element>), failed (<bad-element>),
or not been attempted (<noop-element>).
Appendix B. XML Schema for NETCONF RPC and Protocol Operations
BEGIN
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
targetNamespace="urn:ietf:params:xml:ns:netconf:base:1.0"
elementFormDefault="qualified"
attributeFormDefault="unqualified"
xml:lang="en">
<!--
import standard XML definitions
-->
<xs:import namespace="http://www.w3.org/XML/1998/namespace"
schemaLocation="http://www.w3.org/2001/xml.xsd">
<xs:annotation>
<xs:documentation>
This import accesses the xml: attribute groups for the
xml:lang as declared on the error-message element.
</xs:documentation>
</xs:annotation>
</xs:import>
<!--
message-id attribute
-->
<xs:simpleType name="messageIdType">
<xs:restriction base="xs:string">
<xs:maxLength value="4095"/>
</xs:restriction>
</xs:simpleType>
<!--
Types used for session-id
-->
<xs:simpleType name="SessionId">
<xs:restriction base="xs:unsignedInt">
<xs:minInclusive value="1"/>
</xs:restriction>
</xs:simpleType>
<xs:simpleType name="SessionIdOrZero">
<xs:restriction base="xs:unsignedInt"/>
</xs:simpleType>
<!--
<rpc> element
-->
<xs:complexType name="rpcType">
<xs:sequence>
<xs:element ref="rpcOperation"/>
</xs:sequence>
<xs:attribute name="message-id" type="messageIdType"
use="required"/>
<!--
Arbitrary attributes can be supplied with <rpc> element.
-->
<xs:anyAttribute processContents="lax"/>
</xs:complexType>
<xs:element name="rpc" type="rpcType"/>
<!--
data types and elements used to construct rpc-errors
-->
<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="in-use"/>
<xs:enumeration value="invalid-value"/>
<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="unknown-namespace"/>
<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">
<xs:restriction base="xs:string">
<xs:enumeration value="error"/>
<xs:enumeration value="warning"/>
</xs:restriction>
</xs:simpleType>
<xs:complexType name="errorInfoType">
<xs:sequence>
<xs:choice>
<xs:element name="session-id" type="SessionIdOrZero"/>
<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:sequence>
<xs:element name="bad-attribute" type="xs:QName"
minOccurs="0" maxOccurs="1"/>
<xs:element name="bad-element" type="xs:QName"
minOccurs="0" maxOccurs="1"/>
<xs:element name="ok-element" type="xs:QName"
minOccurs="0" maxOccurs="1"/>
<xs:element name="err-element" type="xs:QName"
minOccurs="0" maxOccurs="1"/>
<xs:element name="noop-element" type="xs:QName"
minOccurs="0" maxOccurs="1"/>
<xs:element name="bad-namespace" type="xs:QName"
minOccurs="0" maxOccurs="1"/>
</xs:sequence>
</xs:sequence>
</xs:choice>
<!-- elements from any other namespace are also allowed
to follow the NETCONF elements -->
<xs:any namespace="##other"
minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="rpcErrorType">
<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" minOccurs="0">
<xs:complexType>
<xs:simpleContent>
<xs:extension base="xs:string">
<xs:attribute ref="xml:lang" use="optional"/>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
</xs:element>
<xs:element name="error-info" type="errorInfoType"
minOccurs="0"/>
</xs:sequence>
</xs:complexType>
<!--
<rpc-reply> element
-->
<xs:complexType name="rpcReplyType">
<xs:choice>
<xs:element name="ok"/>
<xs:group ref="rpcResponse"/>
</xs:choice>
<xs:attribute name="message-id" type="messageIdType"
use="optional"/>
<!--
Any attributes supplied with <rpc> element must be returned
on <rpc-reply>.
-->
<xs:anyAttribute processContents="lax"/>
</xs:complexType>
<xs:group name="rpcResponse">
<xs:sequence>
<xs:element name="rpc-error" type="rpcErrorType"
minOccurs="0" maxOccurs="unbounded"/>
<xs:element name="data" type="dataInlineType" minOccurs="0"/>
</xs:sequence>
</xs:group>
<xs:element name="rpc-reply" type="rpcReplyType"/>
<!--
Type for <test-option> parameter to <edit-config>
-->
<xs:simpleType name="testOptionType">
<xs:restriction base="xs:string">
<xs:enumeration value="test-then-set"/>
<xs:enumeration value="set"/>
</xs:restriction>
</xs:simpleType>
<!--
Type for <error-option> parameter to <edit-config>
-->
<xs:simpleType name="errorOptionType">
<xs:restriction base="xs:string">
<xs:annotation>
<xs:documentation>
Use of the rollback-on-error value requires
the :rollback-on-error capability.
</xs:documentation>
</xs:annotation>
<xs:enumeration value="stop-on-error"/>
<xs:enumeration value="continue-on-error"/>
<xs:enumeration value="rollback-on-error"/>
</xs:restriction>
</xs:simpleType>
<!--
rpcOperationType: used as a base type for all
NETCONF operations
-->
<xs:complexType name="rpcOperationType"/>
<xs:element name="rpcOperation"
type="rpcOperationType" abstract="true"/>
<!--
Type for <config> element
-->
<xs:complexType name="configInlineType">
<xs:complexContent>
<xs:extension base="xs:anyType"/>
</xs:complexContent>
</xs:complexType>
<!--
Type for <data> element
-->
<xs:complexType name="dataInlineType">
<xs:complexContent>
<xs:extension base="xs:anyType"/>
</xs:complexContent>
</xs:complexType>
<!--
Type for <filter> element
-->
<xs:simpleType name="FilterType">
<xs:restriction base="xs:string">
<xs:annotation>
<xs:documentation>
Use of the xpath value requires the :xpath capability.
</xs:documentation>
</xs:annotation>
<xs:enumeration value="subtree"/>
<xs:enumeration value="xpath"/>
</xs:restriction>
</xs:simpleType>
<xs:complexType name="filterInlineType">
<xs:complexContent>
<xs:extension base="xs:anyType">
<xs:attribute name="type"
type="FilterType" default="subtree"/>
<!-- if type="xpath", the xpath expression
appears in the select element -->
<xs:attribute name="select"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!--
configuration datastore names
-->
<xs:annotation>
<xs:documentation>
The startup datastore can be used only if the :startup
capability is advertised. The candidate datastore can
be used only if the :candidate datastore is advertised.
</xs:documentation>
</xs:annotation>
<xs:complexType name="configNameType"/>
<xs:element name="config-name"
type="configNameType" abstract="true"/>
<xs:element name="startup" type="configNameType"
substitutionGroup="config-name"/>
<xs:element name="candidate" type="configNameType"
substitutionGroup="config-name"/>
<xs:element name="running" type="configNameType"
substitutionGroup="config-name"/>
<!--
operation attribute used in <edit-config>
-->
<xs:simpleType name="editOperationType">
<xs:restriction base="xs:string">
<xs:enumeration value="merge"/>
<xs:enumeration value="replace"/>
<xs:enumeration value="create"/>
<xs:enumeration value="delete"/>
</xs:restriction>
</xs:simpleType>
<xs:attribute name="operation"
type="editOperationType" default="merge"/>
<!--
<default-operation> element
-->
<xs:simpleType name="defaultOperationType">
<xs:restriction base="xs:string">
<xs:enumeration value="merge"/>
<xs:enumeration value="replace"/>
<xs:enumeration value="none"/>
</xs:restriction>
</xs:simpleType>
<!--
<url> element
-->
<xs:complexType name="configURIType">
<xs:annotation>
<xs:documentation>
Use of the url element requires the :url capability.
</xs:documentation>
</xs:annotation>
<xs:simpleContent>
<xs:extension base="xs:anyURI"/>
</xs:simpleContent>
</xs:complexType>
<!--
Type for <source> element (except <get-config>)
-->
<xs:complexType name="rpcOperationSourceType">
<xs:choice>
<xs:element name="config" type="configInlineType"/>
<xs:element ref="config-name"/>
<xs:element name="url" type="configURIType"/>
</xs:choice>
</xs:complexType>
<!--
Type for <source> element in <get-config>
-->
<xs:complexType name="getConfigSourceType">
<xs:choice>
<xs:element ref="config-name"/>
<xs:element name="url" type="configURIType"/>
</xs:choice>
</xs:complexType>
<!--
Type for <target> element
-->
<xs:complexType name="rpcOperationTargetType">
<xs:choice>
<xs:element ref="config-name"/>
<xs:element name="url" type="configURIType"/>
</xs:choice>
</xs:complexType>
<!--
<get-config> operation
-->
<xs:complexType name="getConfigType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="source"
type="getConfigSourceType"/>
<xs:element name="filter"
type="filterInlineType" minOccurs="0"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="get-config" type="getConfigType"
substitutionGroup="rpcOperation"/>
<!--
<edit-config> operation
-->
<xs:complexType name="editConfigType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:annotation>
<xs:documentation>
Use of the test-option element requires the
:validate capability. Use of the url element
requires the :url capability.
</xs:documentation>
</xs:annotation>
<xs:element name="target"
type="rpcOperationTargetType"/>
<xs:element name="default-operation"
type="defaultOperationType"
minOccurs="0"/>
<xs:element name="test-option"
type="testOptionType"
minOccurs="0"/>
<xs:element name="error-option"
type="errorOptionType"
minOccurs="0"/>
<xs:choice>
<xs:element name="config"
type="configInlineType"/>
<xs:element name="url"
type="configURIType"/>
</xs:choice>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="edit-config" type="editConfigType"
substitutionGroup="rpcOperation"/>
<!--
<copy-config> operation
-->
<xs:complexType name="copyConfigType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="target" type="rpcOperationTargetType"/>
<xs:element name="source" type="rpcOperationSourceType"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="copy-config" type="copyConfigType"
substitutionGroup="rpcOperation"/>
<!--
<delete-config> operation
-->
<xs:complexType name="deleteConfigType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="target" type="rpcOperationTargetType"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="delete-config" type="deleteConfigType"
substitutionGroup="rpcOperation"/>
<!--
<get> operation
-->
<xs:complexType name="getType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="filter"
type="filterInlineType" minOccurs="0"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="get" type="getType"
substitutionGroup="rpcOperation"/>
<!--
<lock> operation
-->
<xs:complexType name="lockType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="target"
type="rpcOperationTargetType"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="lock" type="lockType"
substitutionGroup="rpcOperation"/>
<!--
<unlock> operation
-->
<xs:complexType name="unlockType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="target" type="rpcOperationTargetType"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="unlock" type="unlockType"
substitutionGroup="rpcOperation"/>
<!--
<validate> operation
-->
<xs:complexType name="validateType">
<xs:annotation>
<xs:documentation>
The validate operation requires the :validate capability.
</xs:documentation>
</xs:annotation>
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="source" type="rpcOperationSourceType"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="validate" type="validateType"
substitutionGroup="rpcOperation"/>
<!--
<commit> operation
-->
<xs:simpleType name="confirmTimeoutType">
<xs:restriction base="xs:unsignedInt">
<xs:minInclusive value="1"/>
</xs:restriction>
</xs:simpleType>
<xs:complexType name="commitType">
<xs:annotation>
<xs:documentation>
The commit operation requires the :candidate capability.
</xs:documentation>
</xs:annotation>
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:annotation>
<xs:documentation>
Use of the confirmed and confirm-timeout elements
requires the :confirmed-commit capability.
</xs:documentation>
</xs:annotation>
<xs:element name="confirmed" minOccurs="0"/>
<xs:element name="confirm-timeout"
type="confirmTimeoutType"
minOccurs="0"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="commit" type="commitType"
substitutionGroup="rpcOperation"/>
<!--
<discard-changes> operation
-->
<xs:complexType name="discardChangesType">
<xs:annotation>
<xs:documentation>
The discard-changes operation requires the
:candidate capability.
</xs:documentation>
</xs:annotation>
<xs:complexContent>
<xs:extension base="rpcOperationType"/>
</xs:complexContent>
</xs:complexType>
<xs:element name="discard-changes"
type="discardChangesType"
substitutionGroup="rpcOperation"/>
<!--
<close-session> operation
-->
<xs:complexType name="closeSessionType">
<xs:complexContent>
<xs:extension base="rpcOperationType"/>
</xs:complexContent>
</xs:complexType>
<xs:element name="close-session" type="closeSessionType"
substitutionGroup="rpcOperation"/>
<!--
<kill-session> operation
-->
<xs:complexType name="killSessionType">
<xs:complexContent>
<xs:extension base="rpcOperationType">
<xs:sequence>
<xs:element name="session-id"
type="SessionId" minOccurs="1"/>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<xs:element name="kill-session" type="killSessionType"
substitutionGroup="rpcOperation"/>
<!--
<hello> element
-->
<xs:element name="hello">
<xs:complexType>
<xs:sequence>
<xs:element name="capabilities">
<xs:complexType>
<xs:sequence>
<xs:element name="capability" type="xs:anyURI"
maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="session-id"
type="SessionId" minOccurs="0"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
END
Appendix C. Capability Template
C.1. capability-name (template)
C.1.1. Overview
C.1.2. Dependencies
C.1.3. Capability Identifier
The {name} capability is identified by the following capability
string:
{capability uri}
C.1.4. New Operations
C.1.4.1. <op-name>
C.1.5. Modifications to Existing Operations
C.1.5.1. <op-name>
If existing operations are not modified by this capability, this
section may be omitted.
C.1.6. Interactions with Other Capabilities
If this capability does not interact with other capabilities, this
section may be omitted.
Appendix D. Configuring Multiple Devices with NETCONF
D.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.
D.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.
The lock can be acquired using the <lock> operation.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<lock>
<target>
<running/>
</target>
</lock>
</rpc>
D.1.2. Loading the Update
The configuration can be loaded onto the device without impacting the
running system. If the :url capability is supported and lists "file"
as a supported scheme, incoming changes can be placed in a local
file.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<copy-config>
<target>
<url>file://incoming.conf</url>
</target>
<source>
<config>
<!-- place incoming configuration here -->
</config>
</source>
</copy-config>
</rpc>
If the :candidate capability is supported, the candidate
configuration can be used.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<candidate/>
</target>
<config>
<!-- place incoming configuration here -->
</config>
</edit-config>
</rpc>
If the update fails, the user file can be deleted using the
<delete-config> operation, or the candidate configuration can be
reverted using the <discard-changes> operation.
D.1.3. Validating the Incoming Configuration
Before the incoming configuration is applied, validating it is often
useful. Validation allows the application to gain confidence that
the change will succeed and simplifies recovery if it does not.
If the device supports the :url capability and lists "file" as a
supported scheme, use the <validate> operation with the <source>
parameter set to the proper user file:
<rpc message-id="101"
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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<validate>
<source>
<candidate/>
</source>
</validate>
</rpc>
D.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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<copy-config>
<target>
<url>file://checkpoint.conf</url>
</target>
<source>
<running/>
</source>
</copy-config>
</rpc>
To restore the checkpoint file, reverse the source and target
parameters.
D.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 and lists "file" as a
supported scheme, use the <edit-config> operation to merge the
incoming configuration into the running configuration.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<url>file://incoming.conf</url>
</config>
</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
reversion to the original configuration if connectivity to the device
fails.
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<commit>
<confirmed/>
<confirm-timeout>120</confirm-timeout>
</commit>
</rpc>
D.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
of the BGP peer that was just added).
D.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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<copy-config>
<target>
<startup/>
</target>
<source>
<running/>
</source>
</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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<commit/>
</rpc>
D.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="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<unlock>
<target>
<running/>
</target>
</unlock>
</rpc>
D.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
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 multi-device operations. The first class
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.
An 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 they were
changed. After the changes have been completely implemented or
completely discarded, the locks on each device can be released.
Appendix E. Deferred Features
The following features have been deferred until a future revision of
this document.
o Granular locking of configuration objects.
o Named configuration files/datastores.
o Support for multiple NETCONF channels.
o Asynchronous notifications.
o Explicit protocol support for rollback of configuration changes to
prior versions.
Editor's Address
Rob Enns
Juniper Networks
1194 North Mathilda Ave
Sunnyvale, CA 94089
US
EMail: rpe@juniper.net
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