draft-ietf-netconf-with-defaults-01.txt   draft-ietf-netconf-with-defaults-02.txt 
NETCONF A. Bierman NETCONF A. Bierman
Internet-Draft Netconf Central Internet-Draft Netconf Central
Intended status: Standards Track B. Lengyel Intended status: Standards Track B. Lengyel
Expires: October 8, 2009 Ericsson Expires: January 4, 2010 Ericsson
April 06, 2009 July 03, 2009
With-defaults capability for NETCONF With-defaults capability for NETCONF
draft-ietf-netconf-with-defaults-01 draft-ietf-netconf-with-defaults-02
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on October 8, 2009. This Internet-Draft will expire on January 4, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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the NETCONF manger will need this data as part of the NETCONF <rpc- the NETCONF manger will need this data as part of the NETCONF <rpc-
reply> messages. This document defines a capability-based extension reply> messages. This document defines a capability-based extension
to the NETCONF protocol that allows the NETCONF manager to control to the NETCONF protocol that allows the NETCONF manager to control
whether default values are part of NETCONF <rpc-reply> messages. whether default values are part of NETCONF <rpc-reply> messages.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1. Requirements Notation . . . . . . . . . . . . . . . . 3 1.1.1. Requirements Notation . . . . . . . . . . . . . . . . 3
1.1.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . 3 1.1.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . 4
2. With-defaults Capability . . . . . . . . . . . . . . . . . . . 4 2. With-defaults Capability . . . . . . . . . . . . . . . . . . . 4
2.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1. Basic handling of default data . . . . . . . . . . . . 4 2.1.1. Basic handling of default data . . . . . . . . . . . . 4
2.2. Dependencies . . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Dependencies . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Capability Identifier . . . . . . . . . . . . . . . . . . 5 2.3. Capability Identifier . . . . . . . . . . . . . . . . . . 5
2.4. New Operations . . . . . . . . . . . . . . . . . . . . . . 5 2.4. New Operations . . . . . . . . . . . . . . . . . . . . . . 5
2.5. Modifications to Existing Operations . . . . . . . . . . . 5 2.5. Modifications to Existing Operations . . . . . . . . . . . 5
3. Interactions with Other Capabilities . . . . . . . . . . . . . 7 3. Interactions with Other Capabilities . . . . . . . . . . . . . 7
4. Data Model XSD . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Data Model XSD . . . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5. ietf-with-defaults YANG Module . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7.1. Other default handling methods in the real world? . . . . 10 8. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2. XSD needed? . . . . . . . . . . . . . . . . . . . . . . . 10 8.1. Other default handling modes in the real world? . . . . . 11
8. Appendix A - Change Log . . . . . . . . . . . . . . . . . . 11 8.2. XSD needed? . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.3. YANG needed? . . . . . . . . . . . . . . . . . . . . . . . 11
8.2. -00 . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 9. Appendix A - Change Log . . . . . . . . . . . . . . . . . . 12
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 9.1. 01-02 . . . . . . . . . . . . . . . . . . . . . . . . . . 12
10. Normative References . . . . . . . . . . . . . . . . . . . . . 13 9.2. 00-01 . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 9.3. -00 . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
11. Normative References . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
The NETCONF protocol defines ways to read configuration data from a The NETCONF protocol defines ways to read configuration data from a
NETCONF agent. Part of this data is not set by the NETCONF manager, NETCONF agent. Part of this data is not set by the NETCONF manager,
but rather a default value is used. In many situations the NETCONF but rather a default value is used. In many situations the NETCONF
manager has a priori knowledge about default data, so the NETCONF manager has a priori knowledge about default data, so the NETCONF
agent does not need to send it to the manager. A priori knowledge agent does not need to send it to the manager. A priori knowledge
can be e.g. a document formally describing the data models supported can be e.g., a document formally describing the data models supported
by the NETCONF agent. by the NETCONF agent.
A networking device may have a large number of default values. Often A networking device may have a large number of default values. Often
the default values are not interesting or specifically defined with a the default values are not interesting or specifically defined with a
"reasonable" value, so that the management user does not have to "reasonable" value, so that the management user does not have to
handle them. For these reasons it is quite common for networking handle them. For these reasons it is quite common for networking
devices to suppress the output of parameters having the default devices to suppress the output of parameters having the default
value. value.
However there are use-cases when a NETCONF manager will need the However there are use-cases when a NETCONF manager will need the
default data from the node: default data from the node:
o The management application often needs a single, definitive and
complete set of configuration values that determine how the a
networking device works.
o Documentation about default values can be unreliable or o Documentation about default values can be unreliable or
unavailable. unavailable.
o Some management applications might not have the capabilities to o Some management applications might not have the capabilities to
correctly parse and interpret formal data models. correctly parse and interpret formal data models.
o Human users might want to understand the received data without o Human users might want to understand the received data without
consultation of the documentation. consultation of the documentation.
In all theses cases the NETCONF manager will need default data as In all theses cases the NETCONF manager will need default data as
part of the NETCONF <rpc-reply> messages. part of the NETCONF <rpc-reply> messages.
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1.1.2. NETCONF Terms 1.1.2. NETCONF Terms
o Default data: Data that is set or used by the NETCONF agent o Default data: Data that is set or used by the NETCONF agent
whenever the NETCONF manager does not provide a specific value for whenever the NETCONF manager does not provide a specific value for
the relevant data item. Default values are often specified in the relevant data item. Default values are often specified in
documents describing the data models supported by the NETCONF documents describing the data models supported by the NETCONF
agent. In the context of this document only configuration data is agent.
considered, state data is excluded.
o Explicitly set default data: Data that is explicitly set by the o Explicitly set default data: Data that is explicitly set by the
NETCONF manager to it's default value. Some agents MIGHT treat NETCONF manager to its default value. Some agents MAY treat
explicitly set default data as simple default data, as they MIGHT explicitly set default data as simple default data, as they MAY
not be able to differentiate between them. not be able to differentiate between them.
In addition the following terms are defined in RFC 4741 and are not In addition the following terms are defined in RFC 4741 and are not
redefined here: redefined here:
o agent o agent
o application o application
o manager o manager
o operation o operation
o RPC o RPC
o RPC request o RPC request
o RPC response o RPC response
2. With-defaults Capability 2. With-defaults Capability
2.1. Overview 2.1. Overview
The :with-defaults capability indicates that the NETCONF agent makes The :with-defaults capability indicates that the NETCONF agent makes
it possible for the NETCONF manager to control whether default data it possible for the NETCONF manager to control whether default data
is part of NETCONF <rpc-reply> messages. The capability only affects is part of NETCONF <rpc-reply> messages. The capability affects both
configuration data not state data. Sending of default data is configuration and state data (while acknowledging that the usage of
controlled for each individual operation separately. The NETCONF default values for state data is less prevalent.) Sending of default
agent MUST also indicate its basic behavior, whether it sends default data is controlled for each individual operation separately. The
data in the absence of any specific request from the NETCONF manager. NETCONF agent MUST also indicate its basic behavior, whether it sends
default data in the absence of any specific request from the NETCONF
manager.
2.1.1. Basic handling of default data 2.1.1. Basic handling of default data
It is not defined in [RFC4741], whether default data is part of the [NETCONF] does not define whether default data is part of the
datastore/data model, or if it is meta data, that influences the datastore/data model, or if it is meta-data that influences the
behavior of the NETCONF server, device but is not actually part of behavior of the NETCONF server, but is not actually part of the
the datastore. This document intentionally avoids deciding this datastore. This document is intended to support either type of
question. implementation, without deciding which approach is better.
As a consequence of this issue, NETCONF servers that do not implement As a consequence of this issue, NETCONF servers that do not implement
the :with-defaults capability may or may not return default data in the :with-defaults capability may or may not return default data in
NETCONF <rpc-reply> messages. NETCONF <rpc-reply> messages.
Different NETCONF agents report default data in different ways. This Different NETCONF agents report default data in different ways. This
document specifies the following three basic methods: document specifies the following three basic modes:
o Report all: All default data is always reported. o report-all: All default data is always reported.
o Trim: Values are not reported if they match the default. o trim: Values are not reported if they match the default.
o Explicit: Report values if they are explicitly set. o explicit: Report values if they are explicitly set. For state
data this has the same effect as report-all
NETCONF servers implementing the :with-defaults capability MUST
support the 'report-all' mode and MAY support other modes.
2.2. Dependencies 2.2. Dependencies
None None
2.3. Capability Identifier 2.3. Capability Identifier
urn:ietf:params:netconf:capability:with-defaults:1.0 urn:ietf:params:netconf:capability:with-defaults:1.0
The identifier MUST have a parameter: "basic". This indicates how The identifier MUST have a parameter: "basic". This indicates how
the agent reports default data in <rpc-reply> messages, in the case the agent reports default data in <rpc-reply> messages, in the case
the manager does not specify the required behavior in the <rpc> the manager does not specify the required behavior in the <rpc>
request. The allowed values of this parameter are report-all, trim, request. The allowed values of this parameter are report-all, trim,
explicit as listed in Section 2.1.1. explicit as listed in Section 2.1.1.
The identifier MAY have another parameter: "supported". This The identifier MAY have another parameter: "also-supported". This
indicates what other default handling methods does the agent support. indicates what other default handling modes does the agent support.
The value of the parameter is a colon separated list of one or two The value of the parameter is a comma separated list of one or two
supported methods. Possible methods are taken from the list in modes that are supported beside the mode indicated in the basic
Section 2.1.1. parameter Possible modes are taken from the list in Section 2.1.1.
Example: Example:
urn:ietf:params:netconf:capability:with-defaults:1.0?basic=report-all urn:ietf:params:netconf:capability:with-defaults:1.0?basic=report-all
urn:ietf:params:netconf:capability:with-defaults:1.0?basic=report- urn:ietf:params:netconf:capability:with-defaults:1.0?basic=report-
all&supported=trim:explicit all&also-supported=trim,explicit
2.4. New Operations 2.4. New Operations
None None
2.5. Modifications to Existing Operations 2.5. Modifications to Existing Operations
A new <with-defaults> XML child element is added to the 'method-name' A new <with-defaults> XML child element is added to the method-name
element. This is the element that indicates the type of the element. This is the element that indicates the type of the
operation e.g. <get>, <get-config> or <copy-config>. If the <with- operation e.g. <get>, <get-config> or <copy-config>. If the <with-
defaults> element is present, it controls the reporting of default defaults> element is present, it controls the reporting of default
data. The agent MUST return default data in the NETCONF <rpc-reply> data. The agent MUST return default data in the NETCONF <rpc-reply>
messages according to the value of the element. messages according to the value of the element.
Allowed values of the with-defaults element are taken from the list Allowed values of the with-defaults element are taken from the list
in Section 2.1.1. The allowed values are restricted to the values in Section 2.1.1. The allowed values are restricted to the values
that the device indicates support for in the with-defaults that the device indicates support for in the with-defaults capability
capability. in the basic or also-supported parameters.
If the <with-defaults> element is not present, the agent follows its If the <with-defaults> element is not present, the agent follows its
basic behavior as indicated by the capability identifier's parameter basic behavior as indicated by the capability identifier's parameter
see Section 2.3. see Section 2.3.
Affected operations: Affected operations:
o <get> o <get>
o <get-config> o <get-config>
o <copy-config> o <copy-config>
<copy-config> is only affected if the target of the operation is a
URL. If the target is a NETCONF datastore (running, candidate or
startup) the capability has no effect.
Other operations that return configuration data SHOULD also handle Other operations that return configuration data SHOULD also handle
default data according to the rules set in this document, and default data according to the rules set in this document, and
explicitly state this in their documentation. If this is not explicitly state this in their documentation. If this is not
specified in the document defining the respective operation, the specified in the document defining the respective operation, the
default handling rules described herein do not affect these default handling rules described herein do not affect these
operations. operations.
The following example shows a <get> operation which is using the The following example shows a <get> operation which is using the
'with-defaults' element. The manager is retrieving the 'interfaces' 'with-defaults' element. The manager is retrieving the 'interfaces'
object, defined in the example.com data model. (In this simple object, defined in the example.com data model. (In this simple
example, the 'name' field is defined as the key, and the 'mtu' field example, the 'name' field is defined as the key, and the 'mtu' field
is the only other data in the <interface> element). The default is the only other data in the <interface> element). The default
value of mtu is '1500'. The basic default handling for the agent is value of mtu is '1500'. The basic default handling for the agent is
"trim". As the 'with-defaults' element has the value 'report-all', "trim". As the 'with-defaults' element has the value 'report-all',
the mtu is returned not just for eth0 but also for eth1. the mtu is returned not just for eth0 but also for eth1.
<rpc message-id="102" <rpc message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get> <get-config>
<with-defaults>report-all</with-defaults> <with-defaults>report-all</with-defaults>
<filter type="subtree"> <filter type="subtree">
<interfaces xmlns="http://example.com/interfaces/1.2"/> <interfaces xmlns="http://example.com/interfaces/1.2"/>
</filter> </filter>
</get> </get-config>
</rpc> </rpc>
<rpc-reply message-id="102" <rpc-reply message-id="102"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data> <data>
<interfaces xmlns="http://example.com/interfaces/1.2"> <interfaces xmlns="http://example.com/interfaces/1.2">
<interface> <interface>
<name>eth0</name> <name>eth0</name>
<mtu>8192</mtu> <mtu>8192</mtu>
</interface> </interface>
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<xs:restriction base="xs:string"> <xs:restriction base="xs:string">
<xs:enumeration value="report-all"/> <xs:enumeration value="report-all"/>
<xs:enumeration value="trim"/> <xs:enumeration value="trim"/>
<xs:enumeration value="explicit"/> <xs:enumeration value="explicit"/>
</xs:restriction> </xs:restriction>
</xs:simpleType> </xs:simpleType>
</xs:attribute> </xs:attribute>
</xs:schema> </xs:schema>
5. IANA Considerations 5. ietf-with-defaults YANG Module
This document registers two URIs for the NETCONF XML namespace in the This section is a placeholder at present.
IETF XML registry [RFC3688]. Note that the capability URN is
compliant to [RFC4741] section 10.3. If the NETCONF workgroup documents basic NETCONF operations in a YANG
module (YAM), this section will include a YAM to formally define the
with-defaults related extension of these operations. The section
will be completed only after the 4741bis defines the basic ietf-
netconf YAM.
6. IANA Considerations
This document registers one capability identifier URN from the
"Network Configuration Protocol (NETCONF) Capability URNs" registry,
and one URI for the NETCONF XML namespace in the "IETF XML registry"
[RFC3688]. Note that the capability URN is compliant to [NETCONF]
section 10.3.
+---------------+---------------------------------------------------+ +---------------+---------------------------------------------------+
| Index | Capability Identifier | | Index | Capability Identifier |
+---------------+---------------------------------------------------+ +---------------+---------------------------------------------------+
| :with-default | urn:ietf:params:netconf:capability:with-defaults: | | :with-default | urn:ietf:params:netconf:capability:with-defaults: |
| s | 1.0 | | s | 1.0 |
+---------------+---------------------------------------------------+ +---------------+---------------------------------------------------+
URI: urn:ietf:params:xml:ns:netconf:with-defaults:1.0 URI: urn:ietf:params:xml:ns:netconf:with-defaults:1.0
Registrant Contact: The IESG. Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace. XML: N/A, the requested URI is an XML namespace.
6. Security Considerations 7. Security Considerations
This document defines a minor extension to existing NETCONF protocol This document defines a minor extension to existing NETCONF protocol
operations. it does not introduce any new or increased security risks operations. it does not introduce any new or increased security risks
into the management system. into the management system.
The 'with-defaults' capability provides manager controls over the The 'with-defaults' capability provides manager controls over the
retrieval of particular types of XML data from a configuration retrieval of particular types of XML data from a configuration
database. They only suppress data that can already be retrieved with database. They only suppress data that can already be retrieved with
the standard protocol operations, and do not add any data to the the standard protocol operations, and do not add any data to the
configuration database. configuration database.
7. Open Issues 8. Open Issues
7.1. Other default handling methods in the real world? 8.1. Other default handling modes in the real world?
Are there any other basic default handling methods out there we need Are there any other basic default handling modes out there we need to
to include? include?
7.2. XSD needed? 8.2. XSD needed?
Is the XSD needed? Does it add any value, any clarity to the Is the XSD needed? Does it add any value, any clarity to the
document? document?
8. Appendix A - Change Log Proposal: XSD stays.
8.1. 00-01 8.3. YANG needed?
See section ietf-with-defaults YANG Module.
9. Appendix A - Change Log
9.1. 01-02
report-all made mandatory
Placeholder for YAM added, XSD will be removed when 4741 provides the
NETCONF YAM
with-defaults is valid for state data as well (if state data has a
defined default which might not be so frequent). The definition of
explicit was modified for state data.
9.2. 00-01
Changed value set of with-default capability and element Changed value set of with-default capability and element
Added version to URI Added version to URI
8.2. -00 9.3. -00
Created from draft-bierman-netconf-with-defaults-01.txt Created from draft-bierman-netconf-with-defaults-01.txt
It was decided by the NETCONF mailing list, that with-defaults should It was decided by the NETCONF mailing list, that with-defaults should
be a sub-element of each affected operation. While this violates the be a sub-element of each affected operation. While this violates the
XSD of RFC4741 this is acceptable and follows the ideas behind XSD of RFC4741 this is acceptable and follows the ideas behind
NETCONF and YANG. NETCONF and YANG.
Hopefully it will be clarified in the 4741bis RFC whether such Hopefully it will be clarified in the 4741bis RFC whether such
extensions are allowed. extensions are allowed.
9. Acknowledgements 10. Acknowledgements
Thanks to Martin Bjorklund, Sharon Chisholm, Phil Shafer, Juergen Thanks to Martin Bjorklund, Sharon Chisholm, Phil Shafer, Juergen
Schoenwaelder and many other members of the NETCONF WG for providing Schoenwaelder, Washam Fan and many other members of the NETCONF WG
important input to this document. for providing important input to this document.
10. Normative References 11. Normative References
[W3C.REC-xmlschema-2-20041028] [W3C.REC-xmlschema-2-20041028]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
Second Edition", World Wide Web Consortium Second Edition", World Wide Web Consortium
Recommendation REC-xmlschema-2-20041028, October 2004, Recommendation REC-xmlschema-2-20041028, October 2004,
<http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>. <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028>.
[RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741, [NETCONF] Enns, R., "NETCONF Configuration Protocol", RFC 4741,
December 2006. December 2006.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004. January 2004.
Authors' Addresses Authors' Addresses
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