draft-ietf-netmod-revised-datastores-04.txt   draft-ietf-netmod-revised-datastores-05.txt 
Network Working Group M. Bjorklund Network Working Group M. Bjorklund
Internet-Draft Tail-f Systems Internet-Draft Tail-f Systems
Intended status: Standards Track J. Schoenwaelder Updates: 7950 (if approved) J. Schoenwaelder
Expires: February 25, 2018 Jacobs University Intended status: Standards Track Jacobs University
P. Shafer Expires: April 21, 2018 P. Shafer
K. Watsen K. Watsen
Juniper Networks Juniper Networks
R. Wilton R. Wilton
Cisco Systems Cisco Systems
August 24, 2017 October 18, 2017
Network Management Datastore Architecture Network Management Datastore Architecture
draft-ietf-netmod-revised-datastores-04 draft-ietf-netmod-revised-datastores-05
Abstract Abstract
Datastores are a fundamental concept binding the data models written Datastores are a fundamental concept binding the data models written
in the YANG data modeling language to network management protocols in the YANG data modeling language to network management protocols
such as NETCONF and RESTCONF. This document defines an architectural such as NETCONF and RESTCONF. This document defines an architectural
framework for datastores based on the experience gained with the framework for datastores based on the experience gained with the
initial simpler model, addressing requirements that were not well initial simpler model, addressing requirements that were not well
supported in the initial model. supported in the initial model.
skipping to change at page 1, line 41 skipping to change at page 1, line 41
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This Internet-Draft will expire on February 25, 2018. This Internet-Draft will expire on April 21, 2018.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Original Model of Datastores . . . . . . . . . . . . . . 7 4. Background . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Architectural Model of Datastores . . . . . . . . . . . . . . 8 4.1. Original Model of Datastores . . . . . . . . . . . . . . 8
4.1. The Startup Configuration Datastore (<startup>) . . . . . 9 5. Architectural Model of Datastores . . . . . . . . . . . . . . 9
4.2. The Candidate Configuration Datastore (<candidate>) . . . 10 5.1. Conventional Configuration Datastores . . . . . . . . . . 10
4.3. The Running Configuration Datastore (<running>) . . . . . 10 5.1.1. The Startup Configuration Datastore (<startup>) . . . 11
4.4. The Intended Configuration Datastore (<intended>) . . . . 10 5.1.2. The Candidate Configuration Datastore (<candidate>) . 11
4.5. Conventional Configuration Datastores . . . . . . . . . . 11 5.1.3. The Running Configuration Datastore (<running>) . . . 11
4.6. Dynamic Configuration Datastores . . . . . . . . . . . . 11 5.1.4. The Intended Configuration Datastore (<intended>) . . 12
4.7. The Operational State Datastore (<operational>) . . . . . 11 5.2. Dynamic Configuration Datastores . . . . . . . . . . . . 13
4.7.1. Remnant Configuration . . . . . . . . . . . . . . . . 12 5.3. The Operational State Datastore (<operational>) . . . . . 13
4.7.2. Missing Resources . . . . . . . . . . . . . . . . . . 13 5.3.1. Remnant Configuration . . . . . . . . . . . . . . . . 14
4.7.3. System-controlled Resources . . . . . . . . . . . . . 13 5.3.2. Missing Resources . . . . . . . . . . . . . . . . . . 14
4.7.4. Origin Metadata Annotation . . . . . . . . . . . . . 13 5.3.3. System-controlled Resources . . . . . . . . . . . . . 15
5. Implications on YANG . . . . . . . . . . . . . . . . . . . . 15 5.3.4. Origin Metadata Annotation . . . . . . . . . . . . . 15
5.1. XPath Context . . . . . . . . . . . . . . . . . . . . . . 15 6. Implications on YANG . . . . . . . . . . . . . . . . . . . . 16
6. YANG Modules . . . . . . . . . . . . . . . . . . . . . . . . 16 6.1. XPath Context . . . . . . . . . . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 7. YANG Modules . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1. Updates to the IETF XML Registry . . . . . . . . . . . . 21 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
7.2. Updates to the YANG Module Names Registry . . . . . . . . 22 8.1. Updates to the IETF XML Registry . . . . . . . . . . . . 23
8. Security Considerations . . . . . . . . . . . . . . . . . . . 22 8.2. Updates to the YANG Module Names Registry . . . . . . . . 23
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22 9. Security Considerations . . . . . . . . . . . . . . . . . . . 23
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24
10.1. Normative References . . . . . . . . . . . . . . . . . . 23 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 24
10.2. Informative References . . . . . . . . . . . . . . . . . 23 11.1. Normative References . . . . . . . . . . . . . . . . . . 25
Appendix A. Guidelines for Defining Datastores . . . . . . . . . 24 11.2. Informative References . . . . . . . . . . . . . . . . . 25
A.1. Define which YANG modules can be used in the datastore . 24 Appendix A. Guidelines for Defining Datastores . . . . . . . . . 26
A.2. Define which subset of YANG-modeled data applies . . . . 25 A.1. Define which YANG modules can be used in the datastore . 26
A.3. Define how data is actualized . . . . . . . . . . . . . . 25 A.2. Define which subset of YANG-modeled data applies . . . . 27
A.4. Define which protocols can be used . . . . . . . . . . . 25 A.3. Define how data is actualized . . . . . . . . . . . . . . 27
A.5. Define YANG identities for the datastore . . . . . . . . 25 A.4. Define which protocols can be used . . . . . . . . . . . 27
Appendix B. Ephemeral Dynamic Configuration Datastore Example . 26 A.5. Define YANG identities for the datastore . . . . . . . . 27
Appendix C. Example Data . . . . . . . . . . . . . . . . . . . . 27 Appendix B. Ephemeral Dynamic Configuration Datastore Example . 28
C.1. System Example . . . . . . . . . . . . . . . . . . . . . 27 Appendix C. Example Data . . . . . . . . . . . . . . . . . . . . 29
C.2. BGP Example . . . . . . . . . . . . . . . . . . . . . . . 29 C.1. System Example . . . . . . . . . . . . . . . . . . . . . 29
C.2.1. Datastores . . . . . . . . . . . . . . . . . . . . . 31 C.2. BGP Example . . . . . . . . . . . . . . . . . . . . . . . 32
C.2.2. Adding a Peer . . . . . . . . . . . . . . . . . . . . 31 C.2.1. Datastores . . . . . . . . . . . . . . . . . . . . . 34
C.2.3. Removing a Peer . . . . . . . . . . . . . . . . . . . 32 C.2.2. Adding a Peer . . . . . . . . . . . . . . . . . . . . 34
C.3. Interface Example . . . . . . . . . . . . . . . . . . . . 33 C.2.3. Removing a Peer . . . . . . . . . . . . . . . . . . . 35
C.3.1. Pre-provisioned Interfaces . . . . . . . . . . . . . 33 C.3. Interface Example . . . . . . . . . . . . . . . . . . . . 36
C.3.2. System-provided Interface . . . . . . . . . . . . . . 34 C.3.1. Pre-provisioned Interfaces . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35 C.3.2. System-provided Interface . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38
1. Introduction 1. Introduction
This document provides an architectural framework for datastores as This document provides an architectural framework for datastores as
they are used by network management protocols such as NETCONF they are used by network management protocols such as NETCONF
[RFC6241], RESTCONF [RFC8040] and the YANG [RFC7950] data modeling [RFC6241], RESTCONF [RFC8040] and the YANG [RFC7950] data modeling
language. Datastores are a fundamental concept binding network language. Datastores are a fundamental concept binding network
management data models to network management protocols. Agreement on management data models to network management protocols. Agreement on
a common architectural model of datastores ensures that data models a common architectural model of datastores ensures that data models
can be written in a network management protocol agnostic way. This can be written in a network management protocol agnostic way. This
architectural framework identifies a set of conceptual datastores but architectural framework identifies a set of conceptual datastores but
it does not mandate that all network management protocols expose all it does not mandate that all network management protocols expose all
these conceptual datastores. This architecture is agnostic with these conceptual datastores. This architecture is agnostic with
regard to the encoding used by network management protocols. regard to the encoding used by network management protocols.
2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Objectives
Network management data objects can often take two different values,
the value configured by the user or an application (configuration)
and the value that the device is actually using (operational state).
These two values may be different for a number of reasons, e.g.,
system internal interactions with hardware, interaction with
protocols or other devices, or simply the time it takes to propagate
a configuration change to the software and hardware components of a
system. Furthermore, configuration and operational state data
objects may have different lifetimes.
The original model of datastores required these data objects to be
modeled twice in the YANG schema, as "config true" objects and as
"config false" objects. The convention adopted by the interfaces
data model ([RFC7223]) and the IP data model ([RFC7277]) was using
two separate branches rooted at the root of the data tree, one branch
for configuration data objects and one branch for operational state
data objects.
The duplication of definitions and the ad-hoc separation of
operational state data from configuration data leads to a number of
problems. Having configuration and operational state data in
separate branches in the data model is operationally complicated and
impacts the readability of module definitions. Furthermore, the
relationship between the branches is not machine readable and filter
expressions operating on configuration and on related operational
state are different.
With the revised architectural model of datastores defined in this
document, the data objects are defined only once in the YANG schema
but independent instantiations can appear in two different
datastores, one for configured values and one for operational state
values. This provides a more elegant and simpler solution to the
problem.
The revised architectural model of datastores supports additional
datastores for systems that support more advanced processing chains
converting configuration to operational state. For example, some
systems support configuration that is not currently used (so called
inactive configuration) or they support configuration templates that
are used to expand configuration data via a common template.
3. Terminology
This document defines the following terminology. Some of the terms This document defines the following terminology. Some of the terms
are revised definitions of terms originally defined in [RFC6241] and are revised definitions of terms originally defined in [RFC6241] and
[RFC7950] (see also section Section 3). The revised definitions are [RFC7950] (see also section Section 4). The revised definitions are
semantically equivalent with the definitions found in [RFC6241] and semantically equivalent with the definitions found in [RFC6241] and
[RFC7950]. It is expected that the revised definitions provided in [RFC7950]. It is expected that the revised definitions provided in
this section will replace the definitions in [RFC6241] and [RFC7950] this section will replace the definitions in [RFC6241] and [RFC7950]
when these documents are revised. when these documents are revised.
o datastore: A conceptual place to store and access information. A o datastore: A conceptual place to store and access information. A
datastore might be implemented, for example, using files, a datastore might be implemented, for example, using files, a
database, flash memory locations, or combinations thereof. A database, flash memory locations, or combinations thereof. A
datastore maps to an instantiated YANG data tree. datastore maps to an instantiated YANG data tree.
o configuration: Data that is required to get a device from its o configuration: Data that is required to get a device from its
initial default state into a desired operational state. This data initial default state into a desired operational state. This data
is modeled in YANG using "config true" nodes. Configuration can is modeled in YANG using "config true" nodes. Configuration can
originate from different sources. originate from different sources.
o configuration datastore: A datastore holding configuration. o configuration datastore: A datastore holding configuration.
o running configuration datastore: A configuration datastore holding o running configuration datastore: A configuration datastore holding
the current configuration of the device. It may include inactive the current configuration of the device. It may include
configuration or template-mechanism-oriented configuration that configuration that requires further transformations before it can
require further expansion. This datastore is commonly referred to be applied. This datastore is referred to as "<running>".
as "<running>".
o candidate configuration datastore: A configuration datastore that o candidate configuration datastore: A configuration datastore that
can be manipulated without impacting the device's running can be manipulated without impacting the device's running
configuration datastore and that can be committed to the running configuration datastore and that can be committed to the running
configuration datastore. This datastore is commonly referred to configuration datastore. This datastore is referred to as
as "<candidate>". "<candidate>".
o startup configuration datastore: A configuration datastore holding o startup configuration datastore: A configuration datastore holding
the configuration loaded by the device into the running the configuration loaded by the device into the running
configuration datastore when it boots. This datastore is commonly configuration datastore when it boots. This datastore is referred
referred to as "<startup>". to as "<startup>".
o intended configuration: Configuration that is intended to be used o intended configuration: Configuration that is intended to be used
by the device. For example, intended configuration excludes any by the device. It represents the configuration after all
inactive configuration and it would include configuration produced configuration transformations to <running> have been performed and
through the expansion of templates. is the configuration that the system attempts to apply.
o intended configuration datastore: A configuration datastore o intended configuration datastore: A configuration datastore
holding the complete intended configuration of the device. This holding the complete intended configuration of the device. This
datastore is commonly referred to as "<intended>". datastore is referred to as "<intended>".
o configuration transformation: The addition, modification or
removal of configuration between the <running> and <intended>
datastores. Examples of configuration transformations include the
removal of inactive configuration and the configuration produced
through the expansion of templates.
o conventional configuration datastore: One of the following set of o conventional configuration datastore: One of the following set of
configuration datastores: <running>, <startup>, <candidate>, and configuration datastores: <running>, <startup>, <candidate>, and
<intended>. These datastores share a common schema and protocol <intended>. These datastores share a common schema, and protocol
operations allow copying data between these datastores. The term operations allow copying data between these datastores. The term
"conventional" is chosen as a generic umbrella term for these "conventional" is chosen as a generic umbrella term for these
datastores. datastores.
o conventional configuration: Configuration that is stored in any of o conventional configuration: Configuration that is stored in any of
the conventional configuration datastores. the conventional configuration datastores.
o dynamic configuration datastore: A configuration datastore holding o dynamic configuration datastore: A configuration datastore holding
configuration obtained dynamically during the operation of a configuration obtained dynamically during the operation of a
device through interaction with other systems, rather than through device through interaction with other systems, rather than through
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o system state: The additional data on a system that is not o system state: The additional data on a system that is not
configuration, such as read-only status information and collected configuration, such as read-only status information and collected
statistics. System state is transient and modified by statistics. System state is transient and modified by
interactions with internal components or other systems. System interactions with internal components or other systems. System
state is modeled in YANG using "config false" nodes. state is modeled in YANG using "config false" nodes.
o operational state: The combination of applied configuration and o operational state: The combination of applied configuration and
system state. system state.
o operational state datastore: A datastore holding the complete o operational state datastore: A datastore holding the complete
operational state of the device. This datastore is commonly operational state of the device. This datastore is referred to as
referred to as "<operational>". "<operational>".
o origin: A metadata annotation indicating the origin of a data o origin: A metadata annotation indicating the origin of a data
item. item.
o remnant configuration: Configuration that remains part of the o remnant configuration: Configuration that remains part of the
applied configuration for a period of time after it has been applied configuration for a period of time after it has been
removed from the intended configuration or dynamic configuration. removed from the intended configuration or dynamic configuration.
The time period may be minimal, or may last until all resources The time period may be minimal, or may last until all resources
used by the newly-deleted configuration (e.g., network used by the newly-deleted configuration (e.g., network
connections, memory allocations, file handles) have been connections, memory allocations, file handles) have been
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o server: An entity that provides access to YANG-defined data to a o server: An entity that provides access to YANG-defined data to a
client, over some network management protocol. client, over some network management protocol.
o notification: A server-initiated message indicating that a certain o notification: A server-initiated message indicating that a certain
event has been recognized by the server. event has been recognized by the server.
o remote procedure call: An operation that can be invoked by a o remote procedure call: An operation that can be invoked by a
client on a server. client on a server.
3. Background 4. Background
NETCONF [RFC6241] provides the following definitions: NETCONF [RFC6241] provides the following definitions:
o datastore: A conceptual place to store and access information. A o datastore: A conceptual place to store and access information. A
datastore might be implemented, for example, using files, a datastore might be implemented, for example, using files, a
database, flash memory locations, or combinations thereof. database, flash memory locations, or combinations thereof.
o configuration datastore: The datastore holding the complete set of o configuration datastore: The datastore holding the complete set of
configuration that is required to get a device from its initial configuration that is required to get a device from its initial
default state into a desired operational state. default state into a desired operational state.
skipping to change at page 6, line 44 skipping to change at page 8, line 5
being stored in another datastore. Section 4.4 of this document then being stored in another datastore. Section 4.4 of this document then
concludes that at the time of the writing, modeling state as distinct concludes that at the time of the writing, modeling state as distinct
leafs and distinct branches is the recommended approach. leafs and distinct branches is the recommended approach.
Implementation experience and requests from operators Implementation experience and requests from operators
[I-D.ietf-netmod-opstate-reqs], [I-D.openconfig-netmod-opstate] [I-D.ietf-netmod-opstate-reqs], [I-D.openconfig-netmod-opstate]
indicate that the datastore model initially designed for NETCONF and indicate that the datastore model initially designed for NETCONF and
refined by YANG needs to be extended. In particular, the notion of refined by YANG needs to be extended. In particular, the notion of
intended configuration and applied configuration has developed. intended configuration and applied configuration has developed.
Furthermore, separating operational state from configuration in a 4.1. Original Model of Datastores
separate branch in the data model has been found operationally
complicated, and typically impacts the readability of module
definitions due to overuse of groupings. The relationship between
the branches is not machine readable and filter expressions operating
on configuration and on related operational state are different.
3.1. Original Model of Datastores
The following drawing shows the original model of datastores as it is The following drawing shows the original model of datastores as it is
currently used by NETCONF [RFC6241]: currently used by NETCONF [RFC6241]:
+-------------+ +-----------+ +-------------+ +-----------+
| <candidate> | | <startup> | | <candidate> | | <startup> |
| (ct, rw) |<---+ +--->| (ct, rw) | | (ct, rw) |<---+ +--->| (ct, rw) |
+-------------+ | | +-----------+ +-------------+ | | +-----------+
| | | | | | | |
| +-----------+ | | +-----------+ |
skipping to change at page 7, line 48 skipping to change at page 8, line 48
configuration is made persistent. Note that implementations may also configuration is made persistent. Note that implementations may also
have additional datastores that can propagate changes to <running>. have additional datastores that can propagate changes to <running>.
NETCONF explicitly mentions so called named datastores. NETCONF explicitly mentions so called named datastores.
Some observations: Some observations:
o Operational state has not been defined as a datastore although o Operational state has not been defined as a datastore although
there were proposals in the past to introduce an operational state there were proposals in the past to introduce an operational state
datastore. datastore.
o The NETCONF <get/> operation returns the content of the running o The NETCONF <get> operation returns the contents of <running>
configuration datastore together with the operational state. It together with the operational state. It is therefore necessary
is therefore necessary that "config false" data is in a different that "config false" data is in a different branch than the "config
branch than the "config true" data if the operational state can true" data if the operational state can have a different lifetime
have a different lifetime compared to configuration or if compared to configuration or if configuration is not immediately
configuration is not immediately or successfully applied. or successfully applied.
o Several implementations have proprietary mechanisms that allow o Several implementations have proprietary mechanisms that allow
clients to store inactive data in <running>; this inactive data is clients to store inactive data in <running>. Inactive data is
only exposed to clients that indicate that they support the conceptually removed before validation.
concept of inactive data; clients not indicating support for
inactive data receive the content of <running> with the inactive
data removed. Inactive data is conceptually removed before
validation.
o Some implementations have proprietary mechanisms that allow o Some implementations have proprietary mechanisms that allow
clients to define configuration templates in <running>. These clients to define configuration templates in <running>. These
templates are expanded automatically by the system, and the templates are expanded automatically by the system, and the
resulting configuration is applied internally. resulting configuration is applied internally.
o Some operators have reported that it is essential for them to be o Some operators have reported that it is essential for them to be
able to retrieve the configuration that has actually been able to retrieve the configuration that has actually been
successfully applied, which may be a subset or a superset of the successfully applied, which may be a subset or a superset of the
<running> configuration. <running> configuration.
4. Architectural Model of Datastores 5. Architectural Model of Datastores
Below is a new conceptual model of datastores extending the original Below is a new conceptual model of datastores extending the original
model in order to reflect the experience gained with the original model in order to reflect the experience gained with the original
model. model.
+-------------+ +-----------+ +-------------+ +-----------+
| <candidate> | | <startup> | | <candidate> | | <startup> |
| (ct, rw) |<---+ +--->| (ct, rw) | | (ct, rw) |<---+ +--->| (ct, rw) |
+-------------+ | | +-----------+ +-------------+ | | +-----------+
| | | | | | | |
skipping to change at page 9, line 41 skipping to change at page 10, line 41
v v v v v v
+---------------+ +---------------+
| <operational> | <-- system state | <operational> | <-- system state
| (ct + cf, ro) | | (ct + cf, ro) |
+---------------+ +---------------+
ct = config true; cf = config false ct = config true; cf = config false
rw = read-write; ro = read-only rw = read-write; ro = read-only
boxes denote named datastores boxes denote named datastores
4.1. The Startup Configuration Datastore (<startup>) 5.1. Conventional Configuration Datastores
The startup configuration datastore (<startup>) is an optional The conventional configuration datastores are a set of configuration
configuration datastore holding the configuration loaded by the datastores that share exactly the same schema, allowing data to be
device when it boots. <startup> is only present on devices that copied between them. The term is meant as a generic umbrella
separate the startup configuration from the running configuration description of these datastores. The set of datastores include:
datastore.
o <running>
o <candidate>
o <startup>
o <intended>
Other conventional configuration datastores may be defined in future
documents.
The flow of data between these datastores is depicted in Section 5.
The specific protocols may define explicit operations to copy between
these datastores, e.g., NETCONF defines the <copy-config> operation.
5.1.1. The Startup Configuration Datastore (<startup>)
The startup configuration datastore (<startup>) is a configuration
datastore holding the configuration loaded by the device when it
boots. <startup> is only present on devices that separate the
startup configuration from the running configuration datastore.
The startup configuration datastore may not be supported by all The startup configuration datastore may not be supported by all
protocols or implementations. protocols or implementations.
On devices that support non-volatile storage, the contents of On devices that support non-volatile storage, the contents of
<startup> will typically persist across reboots via that storage. At <startup> will typically persist across reboots via that storage. At
boot time, the device loads the saved startup configuration into boot time, the device loads the saved startup configuration into
<running>. To save a new startup configuration, data is copied to <running>. To save a new startup configuration, data is copied to
<startup>, either via implicit or explicit protocol operations. <startup>, either via implicit or explicit protocol operations.
4.2. The Candidate Configuration Datastore (<candidate>) 5.1.2. The Candidate Configuration Datastore (<candidate>)
The candidate configuration datastore (<candidate>) is an optional The candidate configuration datastore (<candidate>) is a
configuration datastore that can be manipulated without impacting the configuration datastore that can be manipulated without impacting the
device's current configuration and that can be committed to device's current configuration and that can be committed to
<running>. <running>.
The candidate configuration datastore may not be supported by all The candidate configuration datastore may not be supported by all
protocols or implementations. protocols or implementations.
<candidate> does not typically persist across reboots, even in the <candidate> does not typically persist across reboots, even in the
presence of non-volatile storage. If <candidate> is stored using presence of non-volatile storage. If <candidate> is stored using
non-volatile storage, it should be reset at boot time to the contents non-volatile storage, it is reset at boot time to the contents of
of <running>. <running>.
4.3. The Running Configuration Datastore (<running>) 5.1.3. The Running Configuration Datastore (<running>)
The running configuration datastore (<running>) holds the complete The running configuration datastore (<running>) is a configuration
current configuration on the device. It may include inactive datastore that holds the complete current configuration on the
configuration or template-mechanism-oriented configuration that device. It MAY include configuration that requires further
require further expansion. transformation before it can be applied, e.g., inactive
configuration, or template-mechanism-oriented configuration that
needs further expansion. However, <running> MUST always be a valid
configuration data tree, as defined in Section 8.1 of [RFC7950].
If a device does not have a distinct <startup> and non-volatile is <running> MUST be supported if the device can be configured via
available, the device will typically use that non-volatile storage to conventional configuration datastores.
allow <running> to persist across reboots.
4.4. The Intended Configuration Datastore (<intended>) If a device does not have a distinct <startup> and non-volatile
storage is available, the device will typically use that non-volatile
storage to allow <running> to persist across reboots.
5.1.4. The Intended Configuration Datastore (<intended>)
The intended configuration datastore (<intended>) is a read-only The intended configuration datastore (<intended>) is a read-only
configuration datastore. It is tightly coupled to <running>. When configuration datastore. It represents the configuration after all
data is written to <running>, the data that is to be validated is configuration transformations to <running> are performed (e.g.,
also conceptually written to <intended>. Validation is performed on template expansion, removal of inactive configuration), and is the
the contents of <intended>. configuration that the system attempts to apply.
<intended> is tightly coupled to <running>. Whenever data is written
to <running>, then <intended> MUST also be immediately updated by
performing all necessary configuration transformations to the
contents of <running> and then <intended> is validated.
<intended> MAY also be updated independently of <running> if the
effect of a configuration transformation changes, but <intended> MUST
always be a valid configuration data tree, as defined in Section 8.1
of [RFC7950].
For simple implementations, <running> and <intended> are identical. For simple implementations, <running> and <intended> are identical.
The contents of <intended> are also related to the "config true"
subset of <operational>, and hence a client can determine to what
extent the intended configuration is currently in use by checking
whether the contents of <intended> also appear in <operational>.
<intended> does not persist across reboots; its relationship with <intended> does not persist across reboots; its relationship with
<running> makes that unnecessary. <running> makes that unnecessary.
Currently there are no standard mechanisms defined that affect Currently there are no standard mechanisms defined that affect
<intended> so that it would have different contents than <running>, <intended> so that it would have different content than <running>,
but this architecture allows for such mechanisms to be defined. but this architecture allows for such mechanisms to be defined.
One example of such a mechanism is support for marking nodes as One example of such a mechanism is support for marking nodes as
inactive in <running>. Inactive nodes are not copied to <intended>, inactive in <running>. Inactive nodes are not copied to <intended>.
and are thus not taken into account when validating the A second example is support for templates, which can perform
configuration. transformations on the configuration from <running> to the
configuration written to <intended>.
Another example is support for templates. Templates are expanded
when copied into <intended>, and the expanded result is validated.
4.5. Conventional Configuration Datastores
The conventional configuration datastores are a set of configuration
datastores that share a common schema, allowing data to be copied
between them. The term is meant as a generic umbrella description of
these datastores. The set of datastores include:
o <running>
o <candidate>
o <startup>
o <intended>
Other conventional configuration datastores may be defined in future
documents.
The flow of data between these datastores is depicted in section
Section 4.
The specific protocols may define explicit operations to copy between
these datastores, e.g., NETCONF's <copy-config> operation.
4.6. Dynamic Configuration Datastores 5.2. Dynamic Configuration Datastores
The model recognizes the need for dynamic configuration datastores The model recognizes the need for dynamic configuration datastores
that are, by definition, not part of the persistent configuration of that are, by definition, not part of the persistent configuration of
a device. In some contexts, these have been termed ephemeral a device. In some contexts, these have been termed ephemeral
datastores since the information is ephemeral, i.e., lost upon datastores since the information is ephemeral, i.e., lost upon
reboot. The dynamic configuration datastores interact with the rest reboot. The dynamic configuration datastores interact with the rest
of the system through <operational>. of the system through <operational>.
4.7. The Operational State Datastore (<operational>) 5.3. The Operational State Datastore (<operational>)
The operational state datastore (<operational>) is a read-only The operational state datastore (<operational>) is a read-only
datastore that consists of all "config true" and "config false" nodes datastore that consists of all "config true" and "config false" nodes
defined in the schema. In the original NETCONF model the operational defined in the schema. In the original NETCONF model the operational
state only had "config false" nodes. The reason for incorporating state only had "config false" nodes. The reason for incorporating
"config true" nodes here is to be able to expose all operational "config true" nodes here is to be able to expose all operational
settings without having to replicate definitions in the data models. settings without having to replicate definitions in the data models.
<operational> contains system state and all configuration actually <operational> contains system state and all configuration actually
used by the system. This includes all applied configuration from used by the system. This includes all applied configuration from
skipping to change at page 12, line 22 skipping to change at page 13, line 38
configuration datastores. configuration datastores.
Requests to retrieve nodes from <operational> always return the value Requests to retrieve nodes from <operational> always return the value
in use if the node exists, regardless of any default value specified in use if the node exists, regardless of any default value specified
in the YANG module. If no value is returned for a given node, then in the YANG module. If no value is returned for a given node, then
this implies that the node is not used by the device. this implies that the node is not used by the device.
The interpretation of what constitutes as being "in use" by the The interpretation of what constitutes as being "in use" by the
system is dependent on both the schema definition and the device system is dependent on both the schema definition and the device
implementation. Generally, functionality that is enabled and implementation. Generally, functionality that is enabled and
operational on the system would be considered as being 'in use'. operational on the system would be considered as being "in use".
Conversely, functionality that is neither enabled nor operational on Conversely, functionality that is neither enabled nor operational on
the system could be considered as not being 'in use', and hence may the system is considered as not being "in use", and hence SHOULD be
be omitted from <operational>. omitted from <operational>.
<operational> should conform to any constraints specified in the data <operational> SHOULD conform to any constraints specified in the data
model, but given the principal aim of returning "in use" values, it model, but given the principal aim of returning "in use" values, it
is possible that constraints may be violated under some is possible that constraints MAY be violated under some
circumstances, e.g., an abnormal value is "in use", or due to remnant circumstances, e.g., an abnormal value is "in use", the structure of
configuration (described below). Note, that deviations are still a list is being modified, or due to remnant configuration (see
used when it is known in advance that a device does not fully conform Section 5.3.1). Note, that deviations SHOULD be used when it is
to the <operational> schema. known in advance that a device does not fully conform to the
<operational> schema.
Only semantic constraints may be violated, these are the YANG "when", Only semantic constraints MAY be violated, these are the YANG "when",
"must", "mandatory", "unique", "min-elements", and "max-elements" "must", "mandatory", "unique", "min-elements", and "max-elements"
statements. statements; and the uniqueness of key values.
Syntactic constraints cannot be violated, including hierarchical Syntactic constraints MUST NOT be violated, including hierarchical
organization, identifiers, and type-based constraints. If a node in organization, identifiers, and type-based constraints. If a node in
<operational> does not meet the syntactic constraints then it cannot <operational> does not meet the syntactic constraints then it MUST
be returned, and some other mechanism should be used to flag the NOT be returned, and some other mechanism should be used to flag the
error. error.
<operational> does not persist across reboots. <operational> does not persist across reboots.
4.7.1. Remnant Configuration 5.3.1. Remnant Configuration
Changes to configuration may take time to percolate through to Changes to configuration may take time to percolate through to
<operational>. During this period, <operational> may contain nodes <operational>. During this period, <operational> may contain nodes
for both the previous and current configuration, as closely as for both the previous and current configuration, as closely as
possible tracking the current operation of the device. Such remnant possible tracking the current operation of the device. Such remnant
configuration from the previous configuration persists until the configuration from the previous configuration persists until the
system has released resources used by the newly-deleted configuration system has released resources used by the newly-deleted configuration
(e.g., network connections, memory allocations, file handles). (e.g., network connections, memory allocations, file handles).
Remant configuration is a common example of where the semantic Remnant configuration is a common example of where the semantic
constraints defined in the data model cannot be relied upon for constraints defined in the data model cannot be relied upon for
<operational>, since the system may have remnant configuration whose <operational>, since the system may have remnant configuration whose
constraints were valid with the previous configuration and that are constraints were valid with the previous configuration and that are
not valid with the current configuration. Since constraints on not valid with the current configuration. Since constraints on
"config false" nodes may refer to "config true" nodes, remnant "config false" nodes may refer to "config true" nodes, remnant
configuration may force the violation of those constraints. configuration may force the violation of those constraints.
4.7.2. Missing Resources 5.3.2. Missing Resources
Configuration in <intended> can refer to resources that are not Configuration in <intended> can refer to resources that are not
available or otherwise not physically present. In these situations, available or otherwise not physically present. In these situations,
these parts of <intended> are not applied. The data appears in these parts of <intended> are not applied. The data appears in
<intended> but does not appear in <operational>. <intended> but does not appear in <operational>.
A typical example is an interface configuration that refers to an A typical example is an interface configuration that refers to an
interface that is not currently present. In such a situation, the interface that is not currently present. In such a situation, the
interface configuration remains in <intended> but the interface interface configuration remains in <intended> but the interface
configuration will not appear in <operational>. configuration will not appear in <operational>.
Note that configuration validity cannot depend on the current state Note that configuration validity cannot depend on the current state
of such resources, since that would imply the removing a resource of such resources, since that would imply that removing a resource
might render the configuration invalid. This is unacceptable, might render the configuration invalid. This is unacceptable,
especially given that rebooting such a device would fail to boot due especially given that rebooting such a device would cause it to
to an invalid configuration. Instead we allow configuration for restart with an invalid configuration. Instead we allow
missing resources to exist in <running> and <intended>, but it will configuration for missing resources to exist in <running> and
not appear in <operational>. <intended>, but it will not appear in <operational>.
4.7.3. System-controlled Resources 5.3.3. System-controlled Resources
Sometimes resources are controlled by the device and the Sometimes resources are controlled by the device and the
corresponding system controlled data appear in (and disappear from) corresponding system controlled data appears in (and disappears from)
<operational> dynamically. If a system controlled resource has <operational> dynamically. If a system controlled resource has
matching configuration in <intended> when it appears, the system will matching configuration in <intended> when it appears, the system will
try to apply the configuration, which causes the configuration to try to apply the configuration, which causes the configuration to
appear in <operational> eventually (if application of the appear in <operational> eventually (if application of the
configuration was successful). configuration was successful).
4.7.4. Origin Metadata Annotation 5.3.4. Origin Metadata Annotation
As configuration flows into <operational>, it is conceptually marked As configuration flows into <operational>, it is conceptually marked
with a metadata annotation ([RFC7952]) that indicates its origin. with a metadata annotation ([RFC7952]) that indicates its origin.
The origin applies to all configuration nodes except non-presence The origin applies to all configuration nodes except non-presence
containers. The "origin" metadata annotation is defined in containers. The "origin" metadata annotation is defined in
Section 6. The values are YANG identities. The following identities Section 7. The values are YANG identities. The following identities
are defined: are defined:
o origin: abstract base identity from which the other origin o origin: abstract base identity from which the other origin
identities are derived. identities are derived.
o intended: represents configuration provided by <intended>. o intended: represents configuration provided by <intended>.
o dynamic: represents configuration provided by a dynamic o dynamic: represents configuration provided by a dynamic
configuration datastore. configuration datastore.
skipping to change at page 14, line 39 skipping to change at page 16, line 9
default origin is only used when the configuration has not been default origin is only used when the configuration has not been
provided by any other source. provided by any other source.
o unknown: represents configuration for which the system cannot o unknown: represents configuration for which the system cannot
identify the origin. identify the origin.
These identities can be further refined, e.g., there could be These identities can be further refined, e.g., there could be
separate identities for particular types or instances of dynamic separate identities for particular types or instances of dynamic
configuration datastores derived from "dynamic". configuration datastores derived from "dynamic".
For all configuration data nodes in <operational>, the device should For all configuration data nodes in <operational>, the device SHOULD
report the origin that most accurately reflects the source of the report the origin that most accurately reflects the source of the
configuration that is actively being used by the system. configuration that is in use by the system.
In cases where it could be ambiguous as to which origin should be In cases where it could be ambiguous as to which origin should be
used, i.e. where the same data node value has originated from used, i.e. where the same data node value has originated from
multiple sources, then the description statement in the YANG module multiple sources, then the description statement in the YANG module
should be used as guidance for choosing the appropriate origin. For SHOULD be used as guidance for choosing the appropriate origin. For
example: example:
If for a particular configuration node, the associated YANG If for a particular configuration node, the associated YANG
description statement indicates that a protocol negotiated value description statement indicates that a protocol negotiated value
overrides any configured value, then the origin would be reported as overrides any configured value, then the origin would be reported as
"learned", even when a learned value is the same as the configured "learned", even when a learned value is the same as the configured
value. value.
Conversely, if for a particular configuration node, the associated Conversely, if for a particular configuration node, the associated
YANG description statement indicates that a protocol negotiated value YANG description statement indicates that a protocol negotiated value
does not override an explicitly configured value, then the origin does not override an explicitly configured value, then the origin
would be reported as "intended" even when a learned value is the same would be reported as "intended" even when a learned value is the same
as the configured value. as the configured value.
In the case that a device cannot provide an accurate origin for a In the case that a device cannot provide an accurate origin for a
particular configuration data node then it should use the origin particular configuration data node then it SHOULD use the origin
"unknown". "unknown".
5. Implications on YANG 6. Implications on YANG
5.1. XPath Context 6.1. XPath Context
This section updates section 6.4.1 of RFC 7950.
If a server implements the architecture defined in this document, the If a server implements the architecture defined in this document, the
accessible trees for some XPath contexts are refined as follows: accessible trees for some XPath contexts are refined as follows:
o If the XPath expression is defined in a substatement to a data o If the XPath expression is defined in a substatement to a data
node that represents system state, the accessible tree is all node that represents system state, the accessible tree is all
operational state in the server. The root node has all top-level operational state in the server. The root node has all top-level
data nodes in all modules as children. data nodes in all modules as children.
o If the XPath expression is defined in a substatement to a o If the XPath expression is defined in a substatement to a
skipping to change at page 16, line 8 skipping to change at page 17, line 27
o If the XPath expression is defined in a substatement to an o If the XPath expression is defined in a substatement to an
"output" statement in an "rpc" or "action" statement, the "output" statement in an "rpc" or "action" statement, the
accessible tree is the RPC or action operation instance and all accessible tree is the RPC or action operation instance and all
operational state in the server. The root node has top-level data operational state in the server. The root node has top-level data
nodes in all modules as children. Additionally, for an RPC, the nodes in all modules as children. Additionally, for an RPC, the
root node also has the node representing the RPC operation being root node also has the node representing the RPC operation being
defined as a child. The node representing the operation being defined as a child. The node representing the operation being
defined has the operation's output parameters as children. defined has the operation's output parameters as children.
6. YANG Modules 7. YANG Modules
<CODE BEGINS> file "ietf-datastores@2017-08-17.yang" <CODE BEGINS> file "ietf-datastores@2017-08-17.yang"
module ietf-datastores { module ietf-datastores {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-datastores"; namespace "urn:ietf:params:xml:ns:yang:ietf-datastores";
prefix ds; prefix ds;
organization organization
"IETF Network Modeling (NETMOD) Working Group"; "IETF Network Modeling (NETMOD) Working Group";
skipping to change at page 17, line 24 skipping to change at page 18, line 43
reference reference
"RFC XXXX: Network Management Datastore Architecture"; "RFC XXXX: Network Management Datastore Architecture";
} }
/* /*
* Identities * Identities
*/ */
identity datastore { identity datastore {
description description
"Abstract base identity for datastore identities."; "Abstract base identity for datastore identities.";
} }
identity conventional { identity conventional {
base datastore; base datastore;
description description
"Abstract base identity for conventional configuration "Abstract base identity for conventional configuration
datastores."; datastores.";
} }
identity running { identity running {
base conventional; base conventional;
description description
"The running configuration datastore."; "The running configuration datastore.";
} }
identity candidate { identity candidate {
base conventional; base conventional;
description description
"The candidate configuration datastore."; "The candidate configuration datastore.";
} }
identity startup { identity startup {
base conventional; base conventional;
description description
"The startup configuration datastore."; "The startup configuration datastore.";
} }
identity intended { identity intended {
base conventional; base conventional;
description description
"The intended configuration datastore."; "The intended configuration datastore.";
} }
identity dynamic { identity dynamic {
base datastore; base datastore;
description description
"Abstract base identity for dynamic configuration datastores."; "Abstract base identity for dynamic configuration datastores.";
} }
identity operational { identity operational {
base datastore; base datastore;
description description
"The operational state datastore."; "The operational state datastore.";
} }
/* /*
* Type definitions * Type definitions
*/ */
typedef datastore-ref { typedef datastore-ref {
type identityref { type identityref {
base datastore; base datastore;
} }
skipping to change at page 21, line 45 skipping to change at page 23, line 15
data node in the operational datastore. It specifies from data node in the operational datastore. It specifies from
where the node originated. If not specified for a given where the node originated. If not specified for a given
configuration data node then the origin is the same as the configuration data node then the origin is the same as the
origin of its parent node in the data tree. The origin for origin of its parent node in the data tree. The origin for
any top level configuration data nodes must be specified."; any top level configuration data nodes must be specified.";
} }
} }
<CODE ENDS> <CODE ENDS>
7. IANA Considerations 8. IANA Considerations
7.1. Updates to the IETF XML Registry 8.1. Updates to the IETF XML Registry
This document registers two URIs in the IETF XML registry [RFC3688]. This document registers two URIs in the IETF XML registry [RFC3688].
Following the format in [RFC3688], the following registrations are Following the format in [RFC3688], the following registrations are
requested: requested:
URI: urn:ietf:params:xml:ns:yang:ietf-datastores URI: urn:ietf:params:xml:ns:yang:ietf-datastores
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.
URI: urn:ietf:params:xml:ns:yang:ietf-origin URI: urn:ietf:params:xml:ns:yang:ietf-origin
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.
7.2. Updates to the YANG Module Names Registry 8.2. Updates to the YANG Module Names Registry
This document registers two YANG modules in the YANG Module Names This document registers two YANG modules in the YANG Module Names
registry [RFC6020]. Following the format in [RFC6020], the the registry [RFC6020]. Following the format in [RFC6020], the the
following registrations are requested: following registrations are requested:
name: ietf-datastores name: ietf-datastores
namespace: urn:ietf:params:xml:ns:yang:ietf-datastores namespace: urn:ietf:params:xml:ns:yang:ietf-datastores
prefix: ds prefix: ds
reference: RFC XXXX reference: RFC XXXX
name: ietf-origin name: ietf-origin
namespace: urn:ietf:params:xml:ns:yang:ietf-origin namespace: urn:ietf:params:xml:ns:yang:ietf-origin
prefix: or prefix: or
reference: RFC XXXX reference: RFC XXXX
8. Security Considerations 9. Security Considerations
This document discusses an architectural model of datastores for This document discusses an architectural model of datastores for
network management using NETCONF/RESTCONF and YANG. It has no network management using NETCONF/RESTCONF and YANG. It has no
security impact on the Internet. security impact on the Internet.
Although this document specifies several YANG modules, these modules Although this document specifies several YANG modules, these modules
only define identities and meta-data, hence the "YANG module security only define identities and meta-data, hence the "YANG module security
guidelines" do not apply. guidelines" do not apply.
9. Acknowledgments 10. Acknowledgments
This document grew out of many discussions that took place since This document grew out of many discussions that took place since
2010. Several Internet-Drafts ([I-D.bjorklund-netmod-operational], 2010. Several Internet-Drafts ([I-D.bjorklund-netmod-operational],
[I-D.wilton-netmod-opstate-yang], [I-D.ietf-netmod-opstate-reqs], [I-D.wilton-netmod-opstate-yang], [I-D.ietf-netmod-opstate-reqs],
[I-D.kwatsen-netmod-opstate], [I-D.openconfig-netmod-opstate]) and [I-D.kwatsen-netmod-opstate], [I-D.openconfig-netmod-opstate]) and
[RFC6244] touched on some of the problems of the original datastore [RFC6244] touched on some of the problems of the original datastore
model. The following people were authors to these Internet-Drafts or model. The following people were authors to these Internet-Drafts or
otherwise actively involved in the discussions that led to this otherwise actively involved in the discussions that led to this
document: document:
skipping to change at page 23, line 4 skipping to change at page 24, line 23
[I-D.wilton-netmod-opstate-yang], [I-D.ietf-netmod-opstate-reqs], [I-D.wilton-netmod-opstate-yang], [I-D.ietf-netmod-opstate-reqs],
[I-D.kwatsen-netmod-opstate], [I-D.openconfig-netmod-opstate]) and [I-D.kwatsen-netmod-opstate], [I-D.openconfig-netmod-opstate]) and
[RFC6244] touched on some of the problems of the original datastore [RFC6244] touched on some of the problems of the original datastore
model. The following people were authors to these Internet-Drafts or model. The following people were authors to these Internet-Drafts or
otherwise actively involved in the discussions that led to this otherwise actively involved in the discussions that led to this
document: document:
o Lou Berger, LabN Consulting, L.L.C., <lberger@labn.net> o Lou Berger, LabN Consulting, L.L.C., <lberger@labn.net>
o Andy Bierman, YumaWorks, <andy@yumaworks.com> o Andy Bierman, YumaWorks, <andy@yumaworks.com>
o Marcus Hines, Google, <hines@google.com> o Marcus Hines, Google, <hines@google.com>
o Christian Hopps, Deutsche Telekom, <chopps@chopps.org> o Christian Hopps, Deutsche Telekom, <chopps@chopps.org>
o Balazs Lengyel, Ericsson, <balazs.lengyel@ericsson.com>
o Acee Lindem, Cisco Systems, <acee@cisco.com> o Acee Lindem, Cisco Systems, <acee@cisco.com>
o Ladislav Lhotka, CZ.NIC, <lhotka@nic.cz> o Ladislav Lhotka, CZ.NIC, <lhotka@nic.cz>
o Thomas Nadeau, Brocade Networks, <tnadeau@lucidvision.com> o Thomas Nadeau, Brocade Networks, <tnadeau@lucidvision.com>
o Tom Petch, Engineering Networks Ltd, <ietfc@btconnect.com>
o Anees Shaikh, Google, <aashaikh@google.com> o Anees Shaikh, Google, <aashaikh@google.com>
o Rob Shakir, Google, <robjs@google.com> o Rob Shakir, Google, <robjs@google.com>
o Jason Sterne, Nokia, <jason.sterne@nokia.co>
Juergen Schoenwaelder was partly funded by Flamingo, a Network of Juergen Schoenwaelder was partly funded by Flamingo, a Network of
Excellence project (ICT-318488) supported by the European Commission Excellence project (ICT-318488) supported by the European Commission
under its Seventh Framework Programme. under its Seventh Framework Programme.
10. References 11. References
11.1. Normative References
10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
editor.org/info/rfc2119>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<http://www.rfc-editor.org/info/rfc6241>. <https://www.rfc-editor.org/info/rfc6241>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016, RFC 7950, DOI 10.17487/RFC7950, August 2016,
<http://www.rfc-editor.org/info/rfc7950>. <https://www.rfc-editor.org/info/rfc7950>.
[RFC7952] Lhotka, L., "Defining and Using Metadata with YANG", [RFC7952] Lhotka, L., "Defining and Using Metadata with YANG",
RFC 7952, DOI 10.17487/RFC7952, August 2016, RFC 7952, DOI 10.17487/RFC7952, August 2016,
<http://www.rfc-editor.org/info/rfc7952>. <https://www.rfc-editor.org/info/rfc7952>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<http://www.rfc-editor.org/info/rfc8040>. <https://www.rfc-editor.org/info/rfc8040>.
10.2. Informative References [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
11.2. Informative References
[I-D.bjorklund-netmod-operational] [I-D.bjorklund-netmod-operational]
Bjorklund, M. and L. Lhotka, "Operational Data in NETCONF Bjorklund, M. and L. Lhotka, "Operational Data in NETCONF
and YANG", draft-bjorklund-netmod-operational-00 (work in and YANG", draft-bjorklund-netmod-operational-00 (work in
progress), October 2012. progress), October 2012.
[I-D.ietf-netmod-opstate-reqs] [I-D.ietf-netmod-opstate-reqs]
Watsen, K. and T. Nadeau, "Terminology and Requirements Watsen, K. and T. Nadeau, "Terminology and Requirements
for Enhanced Handling of Operational State", draft-ietf- for Enhanced Handling of Operational State", draft-ietf-
netmod-opstate-reqs-04 (work in progress), January 2016. netmod-opstate-reqs-04 (work in progress), January 2016.
skipping to change at page 24, line 27 skipping to change at page 26, line 16
Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling
of Operational State Data in YANG", draft-openconfig- of Operational State Data in YANG", draft-openconfig-
netmod-opstate-01 (work in progress), July 2015. netmod-opstate-01 (work in progress), July 2015.
[I-D.wilton-netmod-opstate-yang] [I-D.wilton-netmod-opstate-yang]
Wilton, R., ""With-config-state" Capability for NETCONF/ Wilton, R., ""With-config-state" Capability for NETCONF/
RESTCONF", draft-wilton-netmod-opstate-yang-02 (work in RESTCONF", draft-wilton-netmod-opstate-yang-02 (work in
progress), December 2015. progress), December 2015.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004, DOI 10.17487/RFC3688, January 2004, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc3688>. editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020, the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010, DOI 10.17487/RFC6020, October 2010, <https://www.rfc-
<http://www.rfc-editor.org/info/rfc6020>. editor.org/info/rfc6020>.
[RFC6244] Shafer, P., "An Architecture for Network Management Using [RFC6244] Shafer, P., "An Architecture for Network Management Using
NETCONF and YANG", RFC 6244, DOI 10.17487/RFC6244, June NETCONF and YANG", RFC 6244, DOI 10.17487/RFC6244, June
2011, <http://www.rfc-editor.org/info/rfc6244>. 2011, <https://www.rfc-editor.org/info/rfc6244>.
[RFC7223] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 7223, DOI 10.17487/RFC7223, May 2014,
<https://www.rfc-editor.org/info/rfc7223>.
[RFC7277] Bjorklund, M., "A YANG Data Model for IP Management",
RFC 7277, DOI 10.17487/RFC7277, June 2014,
<https://www.rfc-editor.org/info/rfc7277>.
Appendix A. Guidelines for Defining Datastores Appendix A. Guidelines for Defining Datastores
The definition of a new datastore in this architecture should be The definition of a new datastore in this architecture should be
provided in a document (e.g., an RFC) purposed to the definition of provided in a document (e.g., an RFC) purposed to the definition of
the datastore. When it makes sense, more than one datastore may be the datastore. When it makes sense, more than one datastore may be
defined in the same document (e.g., when the datastores are logically defined in the same document (e.g., when the datastores are logically
connected). Each datastore's definition should address the points connected). Each datastore's definition should address the points
specified in the sections below. specified in the sections below.
skipping to change at page 25, line 12 skipping to change at page 27, line 10
may constrain which data models can be used in them. If it is may constrain which data models can be used in them. If it is
desirable that a subset of all modules can be targeted to the desirable that a subset of all modules can be targeted to the
datastore, then the documentation defining the datastore must datastore, then the documentation defining the datastore must
indicate this. indicate this.
A.2. Define which subset of YANG-modeled data applies A.2. Define which subset of YANG-modeled data applies
By default, the data in a datastore is modeled by all YANG statements By default, the data in a datastore is modeled by all YANG statements
in the available YANG modules. However, it is possible to specify in the available YANG modules. However, it is possible to specify
criteria that YANG statements must satisfy in order to be present in criteria that YANG statements must satisfy in order to be present in
a datastore. For instance, maybe only "config true" nodes are a datastore. For instance, maybe only "config true" nodes, or
present, or "config false" nodes that also have a specific YANG "config false" nodes that also have a specific YANG extension, are
extension are present in the datastore. present in the datastore.
A.3. Define how data is actualized A.3. Define how data is actualized
The new datastore must specify how it interacts with other The new datastore must specify how it interacts with other
datastores. datastores.
For example, the diagram in Section 4 depicts dynamic configuration For example, the diagram in Section 5 depicts dynamic configuration
datastores feeding into <operational>. How this interaction occurs datastores feeding into <operational>. How this interaction occurs
must be defined by the particular dynamic configuration datastores. has to be defined by the particular dynamic configuration datastores.
In some cases, it may occur implicitly, as soon as the data is put In some cases, it may occur implicitly, as soon as the data is put
into the dynamic configuration datastore while, in other cases, an into the dynamic configuration datastore while, in other cases, an
explicit action (e.g., an RPC) may be required to trigger the explicit action (e.g., an RPC) may be required to trigger the
application of the datastore's data. application of the datastore's data.
A.4. Define which protocols can be used A.4. Define which protocols can be used
By default, it is assumed that both the NETCONF and RESTCONF By default, it is assumed that both the NETCONF and RESTCONF
protocols can be used to interact with a datastore. However, it may protocols can be used to interact with a datastore. However, it may
be that only a specific protocol can be used (e.g., ForCES) or that a be that only a specific protocol can be used (e.g., ForCES) or that a
subset of all protocol operations or capabilities are available subset of all protocol operations or capabilities are available
(e.g., no locking or no XPath-based filtering). (e.g., no locking or no XPath-based filtering).
A.5. Define YANG identities for the datastore A.5. Define YANG identities for the datastore
The datastore must be defined with a YANG identity that uses the The datastore must be defined with a YANG identity that uses the
"ds:datastore" identity or one of its derived identities as its base. "ds:datastore" identity, or one of its derived identities, as its
This identity is necessary so that the datastore can be referenced in base. This identity is necessary so that the datastore can be
protocol operations (e.g., <get-data>). referenced in protocol operations (e.g., <get-data>).
The datastore may also be defined with an identity that uses the The datastore may also be defined with an identity that uses the
"or:origin" identity or one its derived identities as its base. This "or:origin" identity or one its derived identities as its base. This
identity is needed if the datastore interacts with <operational> so identity is needed if the datastore interacts with <operational> so
that data originating from the datastore can be identified as such that data originating from the datastore can be identified as such
via the "origin" metadata attribute defined in Section 6. via the "origin" metadata attribute defined in Section 7.
An example of these guidelines in use is provided in Appendix B. An example of these guidelines in use is provided in Appendix B.
Appendix B. Ephemeral Dynamic Configuration Datastore Example Appendix B. Ephemeral Dynamic Configuration Datastore Example
The section defines documentation for an example dynamic The section defines documentation for an example dynamic
configuration datastore using the guidelines provided in Appendix A. configuration datastore using the guidelines provided in Appendix A.
While this example is very terse, it is expected to be that a While this example is very terse, it is expected to be that a
standalone RFC would be needed when fully expanded. standalone RFC would be needed when fully expanded.
This example defines a dynamic configuration datastore called This example defines a dynamic configuration datastore called
"ephemeral", which is loosely modeled after the work done in the I2RS "ephemeral", which is loosely modeled after the work done in the I2RS
working group. working group.
1. Name : ephemeral +--------------+---------------------------------------------------+
2. YANG modules : all (default) | Name | Value |
3. YANG data nodes : all "config true" data nodes +--------------+---------------------------------------------------+
4. How applied : automatic | Name | ephemeral |
5. Protocols : NC/RC (default) | YANG modules | all (default) |
6. YANG Module : (see below) | YANG nodes | all "config true" data nodes |
| How applied | changes automatically propagated to <operational> |
| Protocols | NC/RC (default) |
| YANG Module | (see below) |
+--------------+---------------------------------------------------+
The example "ephemeral" datastore properties
module example-ds-ephemeral { module example-ds-ephemeral {
yang-version 1.1; yang-version 1.1;
namespace "urn:example:ds-ephemeral"; namespace "urn:example:ds-ephemeral";
prefix eph; prefix eph;
import ietf-datastores { import ietf-datastores {
prefix ds; prefix ds;
} }
import ietf-origin { import ietf-origin {
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leaf ip { leaf ip {
type inet:ip-address; type inet:ip-address;
} }
leaf prefix-length { leaf prefix-length {
type uint8; type uint8;
} }
} }
} }
} }
} }
The operator has configured the host name and two interfaces, so the The operator has configured the host name and two interfaces, so the
contents of <intended> is: contents of <intended> are:
<system xmlns="urn:example:system"> <system xmlns="urn:example:system">
<hostname>foo</hostname> <hostname>foo</hostname>
<interface> <interface>
<name>eth0</name> <name>eth0</name>
<auto-negotiation> <auto-negotiation>
<speed>1000</speed> <speed>1000</speed>
</auto-negotiation> </auto-negotiation>
<address> <address>
<ip>2001:db8::10</ip> <ip>2001:db8::10</ip>
<prefix-length>32</prefix-length> <prefix-length>64</prefix-length>
</address> </address>
</interface> </interface>
<interface> <interface>
<name>eth1</name> <name>eth1</name>
<address> <address>
<ip>2001:db8::20</ip> <ip>2001:db8::20</ip>
<prefix-length>32</prefix-length> <prefix-length>64</prefix-length>
</address> </address>
</interface> </interface>
</system> </system>
The system has detected that the hardware for one of the configured The system has detected that the hardware for one of the configured
interfaces ("eth1") is not yet present, so the configuration for that interfaces ("eth1") is not yet present, so the configuration for that
interface is not applied. Further, the system has received a host interface is not applied. Further, the system has received a host
name and an additional IP address for "eth0" over DHCP. In addition name and an additional IP address for "eth0" over DHCP. In addition
to a default value, a loopback interface is automatically added by to a default value, a loopback interface is automatically added by
the system, and the result of the "speed" auto-negotiation. All of the system, and the result of the "speed" auto-negotiation. All of
this is reflected in <operational>. Note how the origin metadata this is reflected in <operational>. Note how the origin metadata
attribute for several "config true" data nodes is inherited from attribute for several "config true" data nodes is inherited from
their parent data nodes. their parent data nodes.
skipping to change at page 31, line 13 skipping to change at page 34, line 13
There is no separate "bgp-state" hierarchy, with the accompanying There is no separate "bgp-state" hierarchy, with the accompanying
repetition of containment and naming nodes. This makes the model repetition of containment and naming nodes. This makes the model
simpler and more readable. simpler and more readable.
C.2.1. Datastores C.2.1. Datastores
Each datastore represents differing views of these nodes. <running> Each datastore represents differing views of these nodes. <running>
will hold the configuration provided by the operator, for example a will hold the configuration provided by the operator, for example a
single BGP peer. <intended> will conceptually hold the data as single BGP peer. <intended> will conceptually hold the data as
validated, after the removal of data not intended for validation and validated, after the removal of data not intended for validation and
after any local template mechanisms are performed. <operational> will after any local template mechanisms are performed. <operational>
show data from <intended> as well as any "config false" nodes. will show data from <intended> as well as any "config false" nodes.
C.2.2. Adding a Peer C.2.2. Adding a Peer
If the user configures a single BGP peer, then that peer will be If the user configures a single BGP peer, then that peer will be
visible in both <running> and <intended>. It may also appear in visible in both <running> and <intended>. It may also appear in
<candidate>, if the server supports the candidate configuration <candidate>, if the server supports the candidate configuration
datastore. Retrieving the peer will return only the user-specified datastore. Retrieving the peer will return only the user-specified
values. values.
No time delay should exist between the appearance of the peer in No time delay should exist between the appearance of the peer in
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