Internet DRAFT - draft-ietf-netmod-system-config
draft-ietf-netmod-system-config
NETMOD Q. Ma, Ed.
Internet-Draft Q. Wu
Updates: RFC8342, RFC6241, RFC8526, RFC8040 (if C. Feng
approved) Huawei
Intended status: Standards Track 4 January 2023
Expires: 8 July 2023
System-defined Configuration
draft-ietf-netmod-system-config-01
Abstract
This document updates Network Management Datastore Architecture
(NMDA) to define a read-only conventional configuration datastore
called "system" to hold system-defined configurations. To avoid
clients' explicit copy/paste of referenced system-defined
configuration into the target configuration datastore (e.g.,
<running>), a "resolve-system" parameter is defined to allow the
server acting as a "system client" to copy referenced system-defined
nodes automatically. This solution enables clients manipulating the
target configuration datastore (e.g., <running>) to reference nodes
defined in <system>, override values of configurations defined in
<system>, and configure descendant nodes of system-defined nodes.
This document updates RFC 8342, RFC 6241, RFC 8526 and RFC 8040.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on 8 July 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 5
1.3. Updates to RFC 8342 . . . . . . . . . . . . . . . . . . . 5
1.4. Updates to RFC 6241 and RFC 8526 . . . . . . . . . . . . 5
1.5. Updates to RFC 8040 . . . . . . . . . . . . . . . . . . . 6
1.5.1. Query Parameter . . . . . . . . . . . . . . . . . . . 6
1.5.2. Query Parameter URI . . . . . . . . . . . . . . . . . 6
2. Kinds of System Configuration . . . . . . . . . . . . . . . . 7
2.1. Immediately-Active . . . . . . . . . . . . . . . . . . . 7
2.2. Conditionally-Active . . . . . . . . . . . . . . . . . . 7
2.3. Inactive-Until-Referenced . . . . . . . . . . . . . . . . 7
3. The <system> Configuration Datastore . . . . . . . . . . . . 7
4. Static Characteristics of the <system> Configuration
Datastore . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Read-only to Clients . . . . . . . . . . . . . . . . . . 9
4.2. May Change via Software Upgrades . . . . . . . . . . . . 9
4.3. No Impact to <operational> . . . . . . . . . . . . . . . 9
5. Dynamic Behavior . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Conceptual Model of Datastores . . . . . . . . . . . . . 9
5.2. Explicit Declaration of System Configuration . . . . . . 11
5.3. Servers Auto-configuring Referenced System
Configuration . . . . . . . . . . . . . . . . . . . . . . 11
5.4. Modifying (overriding) System Configuration . . . . . . . 12
5.5. Examples . . . . . . . . . . . . . . . . . . . . . . . . 13
5.5.1. Server Configuring of <running> Automatically . . . . 13
5.5.2. Declaring a System-defined Node in <running>
Explicitly . . . . . . . . . . . . . . . . . . . . . 18
5.5.3. Modifying a System-instantiated Leaf's Value . . . . 21
5.5.4. Configuring Descendant Nodes of a System-defined
Node . . . . . . . . . . . . . . . . . . . . . . . . 23
6. The "ietf-system-datastore" Module . . . . . . . . . . . . . 24
6.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 25
6.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 25
6.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 26
7. The "ietf-netconf-resolve-system" Module . . . . . . . . . . 27
7.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 28
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7.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 29
7.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 32
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
8.1. The "IETF XML" Registry . . . . . . . . . . . . . . . . . 34
8.2. The "YANG Module Names" Registry . . . . . . . . . . . . 35
8.3. RESTCONF Capability URN Registry . . . . . . . . . . . . 35
9. Security Considerations . . . . . . . . . . . . . . . . . . . 35
9.1. Regarding the "ietf-system-datastore" YANG Module . . . . 35
9.2. Regarding the "ietf-netconf-resolve-system" YANG
Module . . . . . . . . . . . . . . . . . . . . . . . . . 36
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 36
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 37
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Normative References . . . . . . . . . . . . . . . . . . . . . 37
Informative References . . . . . . . . . . . . . . . . . . . . 38
Appendix A. Key Use Cases . . . . . . . . . . . . . . . . . . . 39
A.1. Device Powers On . . . . . . . . . . . . . . . . . . . . 39
A.2. Client Commits Configuration . . . . . . . . . . . . . . 40
A.3. Operator Installs Card into a Chassis . . . . . . . . . . 41
Appendix B. Changes between Revisions . . . . . . . . . . . . . 42
Appendix C. Open Issues tracking . . . . . . . . . . . . . . . . 42
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42
1. Introduction
Network Management Datastore Architecture (NMDA) [RFC8342] defines
system configuration as the configuration that is supplied by the
device itself and appears in <operational> when it is in use
(Figure 2 in [RFC8342]).
However, there is a desire to enable a server to better structure and
expose the system configuration. NETCONF/RESTCONF clients can
benefit from a standard mechanism to retrieve what system
configuration is available on a server.
In some cases, the NETCONF/RESTCONF client references a system
configuration which isn't present in the target datastore (e.g.,
<running>), thus the configuration is considered invalid. To
facilitate manipulation of the client configuration, having to copy
the entire contents of the system configuration into the target
datastore should be avoided or reduced when possible while ensuring
that all referential integrity constraints are satisfied.
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In some other cases, configuration of descendant nodes of system-
defined configuration needs to be supported. For example, the system
configuration contains an almost empty physical interface, while the
client needs to be able to add, modify, or remove a number of
descendant nodes. Some descendant nodes may not be modifiable (e.g.,
"name" and "type" set by the system).
This document updates NMDA [RFC8342] to define a read-only
conventional configuration datastore called "system" to hold system-
defined configurations. To avoid clients' explicit copy/paste of
referenced system-defined configuration into the target configuration
datastore (e.g., <running>), a "resolve-system" parameter has been
defined to allow the server acting as a "system client" to copy
referenced system-defined nodes automatically. The solution enables
clients manipulating the target configuration datastore (e.g.,
<running>) to overlay and reference nodes defined in <system>,
override values of configurations defined in <system>, and configure
descendant nodes of system-defined nodes.
Conformance to this document requires NMDA servers to implement the
"ietf-system-datastore" YANG module (Section 6).
1.1. Terminology
This document assumes that the reader is familiar with the contents
of [RFC6241], [RFC7950], [RFC8342], [RFC8407], and [RFC8525] and uses
terminologies from those documents.
The following terms are defined in this document:
System configuration: Configuration that is provided by the system
itself. System configuration is present in <system> once it is
created (regardless of being applied by the device), and appears
in <intended> which is subject to validation. Applied system
configuration also appears in <operational> with origin="system".
System configuration datastore: A configuration datastore holding
the complete configuration provided by the system itself. This
datastore is referred to as "<system>".
This document redefines the term "conventional configuration
datastore" in Section 3 of [RFC8342] to add "system" to the list of
conventional configuration datastores:
Conventional configuration datastore: One of the following set of
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configuration datastores: <running>, <startup>, <candidate>,
<system>, and <intended>. These datastores share a common
datastore schema, and protocol operations allow copying data
between these datastores. The term "conventional" is chosen as a
generic umbrella term for these datastores.
1.2. Requirements Language
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.
1.3. Updates to RFC 8342
This document updates RFC 8342 to define a configuration datastore
called "system" to hold system configuration, it also redefines the
term "conventional configuration datastore" from RFC 8342 to add
"system" to the list of conventional configuration datastores. The
contents of <system> datastore are read-only to clients but may
change dynamically. The <system> aware client may retrieve all three
types of system configuration defined in Section 2, reference nodes
defined in <system>, override values of configurations defined in
<system>, and configure descendant nodes of system-defined nodes.
The server will merge <running> and <system> to create <intended>.
As always, system configuration will appear in <operational> with
origin="system" when it is in use.
The <system> datastore makes system configuration visible to clients
in order for being referenced or configurable prior to present in
<operational>.
1.4. Updates to RFC 6241 and RFC 8526
This document augments <edit-config> and <edit-data> RPC operations
defined in [RFC6241] and [RFC8526] respectively, with a new
additional input parameter "resolve-system". The <copy-config> RPC
operation defined in [RFC6241] is also augmented to support "resolve-
system" parameter.
The "resolve-system" parameter is optional and has no value. When it
is provided and the server detects that there is a reference to a
system-defined node during the validation, the server will
automatically copy the referenced system configuration into the
validated datastore to make the configuration valid without the
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client doing so explicitly. Legacy clients interacting with servers
that support this parameter don't see any changes in <edit-
config>/<edit-data> and <copy-config> behaviors.
The server's copy referenced nodes from <system> to the target
datastore MUST be enforced at the end of the <edit-config>/<edit-
data> or <copy-config> operations, regardless of which target
datastore it is.
1.5. Updates to RFC 8040
This document extends Sections 4.8 and 9.1.1 of [RFC8040] to add a
new query parameter "resolve-system" and corresponding query
parameter capability URI.
1.5.1. Query Parameter
The "resolve-system" parameter controls whether to allow a server
copy any referenced system-defined configuration automatically
without the client doing so explicitly. This parameter is only
allowed with no values carried. If this parameter has any unexpected
value, then a "400 Bad Request" status-line is returned.
+----------------+---------+-----------------------------------------+
| Name | Methods | Description |
+----------------+---------+-----------------------------------------+
|resolve-system | POST, | resolve any references not resolved by |
| | PUT | the client and copy referenced |
| | PATCH | system configuration into <running> |
| | | automatically. This parameter can be |
| | | given in any order. |
+----------------+---------+-----------------------------------------+
1.5.2. Query Parameter URI
To enable a RESTCONF client to discover if the "resolve-system" query
parameter is supported by the server, the following capability URI is
defined, which is advertised by the server if supported, using the
"ietf-restconf-monitoring" module defined in RFC 8040:
urn:ietf:params:restconf:capability:resolve-system:1.0
Comment: Should we define a similar capability identifier for NETCONF
protocol?
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2. Kinds of System Configuration
There are three types of system configurations defined in this
document: immediately-active system configuration, conditionally-
active system configuration, and inactive-until-referenced system
configuration.
Active system configuration refers to configuration that is in use by
a device. As per definition of the operational state datastore in
[RFC8342], if system configuration is inactive, it should not appear
in <operational>. However, system configuration is present in
<system> once it is generated, regardless of whether it is active or
not.
2.1. Immediately-Active
Immediately-active system configurations are those generated in
<system> and applied immediately when the device is powered on (e.g.,
a loopback interface), irrespective of physical resource present or
not, a special functionality enabled or not.
2.2. Conditionally-Active
System configurations which are generated in <system> and applied
based on specific conditions being met in a system, e.g., if a
physical resource is present (e.g., insert interface card), the
system will automatically detect it and load pre-provisioned
configuration; when the physical resource is not present(remove
interface card), the system configuration will be automatically
cleared. Another example is when a special functionality is enabled,
e.g., when a QoS feature is enabled, related QoS policies are
automatically created by the system.
2.3. Inactive-Until-Referenced
There are some system configurations predefined (e.g., application
ids, anti-x signatures, trust anchor certs, etc.) as a convenience
for the clients, which must be referenced to be active. The clients
can also define their own configurations for their unique
requirements. Inactive-until-referenced system configurations are
generated in <system> immediately when the device is powered on, but
they are not applied and active until being referenced.
3. The <system> Configuration Datastore
NMDA servers compliant with this document MUST implement a <system>
configuration datastore, and they SHOULD also implement the
<intended> datastore.
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Following guidelines for defining datastores in the appendix A of
[RFC8342], this document introduces a new datastore resource named
'system' that represents the system configuration.
* Name: "system"
* YANG modules: all
* YANG nodes: all "config true" data nodes up to the root of the
tree, generated by the system
* Management operations: The content of the datastore is set by the
server in an implementation dependent manner. The content can not
be changed by management operations via protocols such as NETCONF,
RESTCONF, but may change itself by upgrades and/or when resource-
conditions are met. The datastore can be read using the standard
network management protocols such as NETCONF and RESCTCONF.
* Origin: This document does not define any new origin identity when
it interacts with <intended> datastore and flows into
<operational>. The "system" origin Metadata Annotation [RFC7952]
is used to indicate the origin of a data item is system.
* Protocols: YANG-driven management protocols, such as NETCONF and
RESTCONF.
* Defining YANG module: "ietf-system-datastore".
The datastore's content is defined by the server and read-only to
clients. Upon the content is created or changed, it will be merged
into <intended> datastore. Unlike <factory-default>[RFC8808], it MAY
change dynamically, e.g., depending on factors like device upgrade or
system-controlled resources change (e.g., HW available). The
<system> datastore doesn't persist across reboots; the contents of
<system> will be lost upon reboot and recreated by the system with
the same or changed contents. <factory-reset> RPC operation defined
in [RFC8808] can reset it to its factory default configuration
without including configuration generated due to the system update or
client-enabled functionality.
The <system> datastore is defined as a conventional configuration
datastore and shares a common datastore schema with other
conventional datastores. The <system> configuration datastore must
always be valid, as defined in Section 8.1 of [RFC7950].
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4. Static Characteristics of the <system> Configuration Datastore
4.1. Read-only to Clients
The <system> configuration datastore is a read-only configuration
datastore (i.e., edits towards <system> directly MUST be denied),
though the client may be allowed to override the value of a system-
initialized data node (see Section 5.4).
4.2. May Change via Software Upgrades
System configuration may change dynamically, e.g., depending on
factors like device upgrade or if system-controlled resources (e.g.,
HW available) change. In some implementations, when a QoS feature is
enabled, QoS-related policies are created by the system. If the
system configuration gets changed, YANG notifications (e.g., "push-
change-update" notification) [RFC6470][RFC8639][RFC8641] can be used
to notify the client. Any update of the contents in <system> will
not cause the automatic update of <running>, even if some of the
system configuration has already been copied into <running>
explicitly or automatically before the update.
4.3. No Impact to <operational>
This work intends to have no impact to <operational>. System
configuration will appear in <operational> with "origin=system".
This document enables a subset of those system generated nodes to be
defined like configuration, i.e., made visible to clients in order
for being referenced or configurable prior to present in
<operational>. "Config false" nodes are out of scope, hence existing
"config false" nodes are not impacted by this work.
5. Dynamic Behavior
5.1. Conceptual Model of Datastores
This document introduces a datastore named "system" which is used to
hold all three types of system configurations defined in Section 2.
When the device is powered on, immediately-active system
configuration will be generated in <system> and applied immediately
but inactive-until-referenced system configuration only becomes
active if it is referenced by client-defined configuration. While
conditionally-active system configuration will be created and
immediately applied if the condition on system resources is met when
the device is powered on or running.
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All above three types of system configurations will appear in
<system>. Clients MAY reference nodes defined in <system>, override
values of configurations defined in <system>, and configure
descendant nodes of system-defined nodes, by copying or writing
intended configurations into the target configuration datastore
(e.g., <running>).
The server will merge <running> and <system> to create <intended>, in
which process, the data node appears in <running> takes precedence
over the same node in <system> if the server allows the node to be
modifiable; additional nodes to a list entry or new list/leaf-list
entries appear in <running> extends the list entry or the whole list/
leaf-list defined in <system> if the server allows the list/leaf-list
to be updated. In addition, the <intended> configuration datastore
represents the configuration after all configuration transformation
to <system> are performed (e.g., system-defined template expansion,
removal of inactive system configuration). If a server implements
<intended>, <system> MUST be merged into <intended>.
Servers MUST enforce that configuration references in <running> are
resolved within the <running> datastore and ensure that <running>
contains any referenced system configuration. Clients MUST either
explicitly copy system-defined nodes into <running> or use the
"resolve-system" parameter. The server MUST enforce that the
referenced system nodes configured into <running> by the client is
consistent with <system>. Note that <system> aware clients know how
to discover what nodes exist in <system>. How clients unaware of the
<system> datastore can find appropriate configurations is beyond the
scope of this document.
No matter how the referenced system configurations are copied into
<running>, the nodes copied into <running> would always be returned
after a read of <running>, regardless if the client is <system>
aware.
Configuration defined in <system> is present in <operational> if it
is actively in use by the device, even if a client may delete the
configuration copied from <system> into <running>. For example,
system initializes a value for a particular leaf which is overridden
by the client with a different value in <running>. The client may
delete that node in <running>, in which case system-initialized value
defined in <system> can be still in use and appear in <operational>.
Any deletable system-provided configuration must be defined in
<factory-default> [RFC8808], which is used to initialize <running>
when the device is first-time powered on or reset to its factory
default condition.
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5.2. Explicit Declaration of System Configuration
It is possible for a client to explicitly declare system
configuration nodes in the target datastore (e.g., <running>) with
the same values as in <system>, by configuring a node (list/leaf-list
entry, leaf, etc.) in the target datastore (e.g., <running>) that
matches the same node and value in <system>.
This explicit configuration of system-defined nodes in <running> can
be useful, for example, when the client doesn't want a "system
client" to have a role or hasn't implemented the "resolve-system"
parameter. The client can explicitly declare (i.e., configure in
<running>) the list entries (with at least the keys) for any system
configuration list entries that are referenced elsewhere in
<running>. The client does not necessarily need to declare all the
contents of the list entry (i.e. the descendant nodes) , only the
parts that are required to make the <running> appear valid.
5.3. Servers Auto-configuring Referenced System Configuration
This document defines a new parameter "resolve-system" to the input
for the <edit-config>, <edit-data>, and <copy-config> operations.
Clients that are aware of the "resolve-system" parameter MAY use this
parameter to avoid the requirement to provide a referentially
complete configuration in <running>.
Non-NMDA servers MAY implement this parameter without implementing
the <system> configuration datastore, which would only eliminate the
ability to expose the system configuration via protocol operations.
If a server implements <system>, referenced system configuration is
copied from <system> into the target datastore(e.g., <running>) when
the "resolve-system" parameter is used; otherwise it is an
implementation decision where to copy referenced system configuration
into the target datastore(e.g., <running>).
If the "resolve-system" is present, and the server supports this
capability, the server MUST copy relevant referenced system-defined
nodes into the target datastore (e.g., <running>) without the client
doing the copy/paste explicitly, to resolve any references not
resolved by the client. The server acting as a "system client" like
any other remote clients copies the referenced system-defined nodes
when triggered by the "resolve-system" parameter.
If the "resolve-system" parameter is not given by the client, the
server should not modify <running> in any way otherwise not specified
by the client. Not using capitalized "SHOULD NOT" in the previous
sentence is intentional. The intention is to bring awareness to the
general need to not surprise clients with unexpected changes. It is
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desirable for clients to always opt into using mechanisms having
server-side changes. This document enables a client to opt into this
behavior using the "resolve-system" parameter. RFC 7317 enables a
client to opt into its behavior using a "$0$" prefix (see
ianach:crypt-hash type defined in [RFC7317]).
The server may automatically configure the list entries (with at
least the keys) in the target datastore (e.g., <running>) for any
system configuration list entries that are referenced elsewhere by
the clients. Similarly, not all the contents of the list entry
(i.e., the descendant nodes) are necessarily copied by the server -
only the parts that are required to make the <running> valid. A read
back of <running> (i.e., <get>, <get-config> or <get-data> operation)
returns those automatically copied nodes.
5.4. Modifying (overriding) System Configuration
In some cases, a server may allow some parts of system configuration
to be modified. Modification of system configuration is achieved by
the client writing configuration to <running> that overrides the
system configuration. Configurations defined in <running> take
precedence over system configuration nodes in <system> if the server
allows the nodes to be modified.
For instance, list keys in system configuration can't be changed by a
client, but other descendant nodes in a list entry may be modifiable
or non-modifiable. Leafs and leaf-lists outside of lists may also be
modifiable or non-modifiable. Even if some system configuration has
been copied into <running> earlier, whether it is modifiable or not
in <running> follows general YANG constraints and NACM rules, and
other server-internal restrictions. If a system configuration node
is non-modifiable, then writing a different value for that node MUST
return an error. The immutability of system configuration is further
defined in [I-D.ma-netmod-immutable-flag].
A server may also allow a client to add data nodes to a list entry in
<system> by writing those additional nodes in <running>. Those
additional data nodes may not exist in <system> (i.e., an *addition*
rather than an override).
Comment 1: What if <system> contains a set of values for a leaf-list,
and a client configures another set of values for that leaf-list in
<running>, will the set of values in <running> completely replace the
set of values in <system>? Or the two sets of values are merged
together?
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Comment 2: how "ordered-by user" lists and leaf-lists are merged? Do
the <running> values go before or after, or is this a case where a
full-replace is needed.
5.5. Examples
This section shows some examples of server-configuring of <running>
automatically, declaring a system-defined node in <running>
explicitly, modifying a system-instantiated leaf's value and
configuring descendant nodes of a system-defined node. For each
example, the corresponding XML snippets are provided.
5.5.1. Server Configuring of <running> Automatically
In this subsection, the following fictional module is used:
module example-application {
yang-version 1.1;
namespace "urn:example:application";
prefix "app";
import ietf-inet-types {
prefix "inet";
}
container applications {
list application {
key "name";
leaf name {
type string;
}
leaf protocol {
type enumeration {
enum tcp;
enum udp;
}
}
leaf destination-port {
type inet:port-number;
}
}
}
}
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The server may predefine some applications as a convenience for the
clients. These predefined configurations are applied only after
being referenced by other configurations, which fall into the
"inactive-until-referenced" system configuration as defined in
Section 2. The system-instantiated application entries may be
present in <system> as follows:
<applications xmlns="urn:example:application">
<application>
<name>ftp</name>
<protocol>tcp</protocol>
<destination-port>21</destination-port>
</application>
<application>
<name>tftp</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
<application>
<name>smtp</name>
<protocol>tcp</protocol>
<destination-port>25</destination-port>
</application>
...
</applications>
The client may also define its customized applications. Suppose the
configuration of applications is present in <running> as follows:
<applications xmlns="urn:example:application">
<application>
<name>my-app-1</name>
<protocol>tcp</protocol>
<destination-port>2345</destination-port>
</application>
<application>
<name>my-app-2</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
</applications>
A fictional ACL YANG module is used as follows, which defines a
leafref for the leaf-list "application" data node to refer to an
existing application name.
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module example-acl {
yang-version 1.1;
namespace "urn:example:acl";
prefix "acl";
import example-application {
prefix "app";
}
import ietf-inet-types {
prefix "inet";
}
container acl {
list acl_rule {
key "name";
leaf name {
type string;
}
container matches {
choice l3 {
container ipv4 {
leaf source_address {
type inet:ipv4-prefix;
}
leaf dest_address {
type inet:ipv4-prefix;
}
}
}
choice applications {
leaf-list application {
type leafref {
path "/app:applications/app:application/app:name";
}
}
}
}
leaf packet_action {
type enumeration {
enum forward;
enum drop;
enum redirect;
}
}
}
}
}
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If a client configures an ACL rule referencing system predefined
nodes which are not present in <running>, the client may issue an
<edit-config> operation with the parameter "resolve-system" as
follows:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<acl xmlns="urn:example:acl">
<acl_rule>
<name>allow_access_to_ftp_tftp</name>
<matches>
<ipv4>
<source_address>198.51.100.0/24</source_address>
<dest_address>192.0.2.0/24</dest_address>
</ipv4>
<application>ftp</application>
<application>tftp</application>
<application>my-app-1</application>
</matches>
<packet_action>forward</packet_action>
</acl_rule>
</acl>
</config>
<resolve-system/>
</edit-config>
</rpc>
Then following gives the configuration of applications in <running>
which is returned in the response to a follow-up <get-config>
operation:
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<applications xmlns="urn:example:application">
<application>
<name>my-app-1</name>
<protocol>tcp</protocol>
<destination-port>2345</destination-port>
</application>
<application>
<name>my-app-2</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
<application>
<name>ftp</name>
</application>
<application>
<name>tftp</name>
</application>
</applications>
Then the configuration of applications is present in <operational> as
follows:
<applications xmlns="urn:example:application"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<application>
<name>my-app-1</name>
<protocol>tcp</protocol>
<destination-port>2345</destination-port>
</application>
<application>
<name>my-app-2</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
<application or:origin="or:system">
<name>ftp</name>
<protocol>tcp</protocol>
<destination-port>21</destination-port>
</application>
<application or:origin="or:system">
<name>tftp</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
</applications>
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Since the configuration of application "smtp" is not referenced by
the client, it does not appear in <operational> but only in <system>.
5.5.2. Declaring a System-defined Node in <running> Explicitly
It's also possible for a client to explicitly declare the system-
defined configurations that are referenced. For instance, in the
above example, the client MAY also explicitly configure the following
system defined applications "ftp" and "tftp" only with the list key
"name" before referencing:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<applications xmlns="urn:example:application">
<application>
<name>ftp</name>
</application>
<application>
<name>tftp</name>
</application>
</applications>
</config>
</edit-config>
</rpc>
Then the client issues an <edit-config> operation to configure an ACL
rule referencing applications "ftp" and "tftp" without the parameter
"resolve-system" as follows:
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<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<acl xmlns="urn:example:acl">
<acl_rule>
<name>allow_access_to_ftp_tftp</name>
<matches>
<ipv4>
<source_address>198.51.100.0/24</source_address>
<dest_address>192.0.2.0/24</dest_address>
</ipv4>
<application>ftp</application>
<application>tftp</application>
<application>my-app-1</application>
</matches>
<packet_action>forward</packet_action>
</acl_rule>
</acl>
</config>
</edit-config>
</rpc>
Then following gives the configuration of applications in <running>
which is returned in the response to a follow-up <get-config>
operation, all the configuration of applications are explicitly
configured by the client:
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<applications xmlns="urn:example:application">
<application>
<name>my-app-1</name>
<protocol>tcp</protocol>
<destination-port>2345</destination-port>
</application>
<application>
<name>my-app-2</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
<application>
<name>ftp</name>
</application>
<application>
<name>tftp</name>
</application>
</applications>
Then the configuration of applications is present in <operational> as
follows:
<applications xmlns="urn:example:application"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<application>
<name>my-app-1</name>
<protocol>tcp</protocol>
<destination-port>2345</destination-port>
</application>
<application>
<name>my-app-2</name>
<protocol>udp</protocol>
<destination-port>69</destination-port>
</application>
<application>
<name>ftp</name>
<protocol or:origin="or:system">tcp</protocol>
<destination-port or:origin="or:system">21</destination-port>
</application>
<application>
<name>tftp</name>
<protocol or:origin="or:system">udp</protocol>
<destination-port or:origin="or:system">69</destination-port>
</application>
</applications>
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Since the application names "ftp" and "tftp" are explicitly
configured by the client, they take precedence over the values in
<system>, the "origin" attribute will be set to "intended".
5.5.3. Modifying a System-instantiated Leaf's Value
In this subsection, we will use this fictional QoS data model:
module example-qos-policy {
yang-version 1.1;
namespace "urn:example:qos";
prefix "qos";
container qos-policies {
list policy {
key "name";
leaf name {
type string;
}
list queue {
key "queue-id";
leaf queue-id {
type int32 {
range "1..32";
}
}
leaf maximum-burst-size {
type int32 {
range "0..100";
}
}
}
}
}
}
Suppose a client creates a qos policy "my-policy" with 4 system
instantiated queues(1~4). The configuration of qos-policies is
present in <system> as follows:
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<qos-policies xmlns="urn:example:qos">
<name>my-policy</name>
<queue>
<queue-id>1</queue-id>
<maximum-burst-size>50</maximum-burst-size>
</queue>
<queue>
<queue-id>2</queue-id>
<maximum-burst-size>60</maximum-burst-size>
</queue>
<queue>
<queue-id>3</queue-id>
<maximum-burst-size>70</maximum-burst-size>
</queue>
<queue>
<queue-id>4</queue-id>
<maximum-burst-size>80</maximum-burst-size>
</queue>
</qos-policies>
A client modifies the value of maximum-burst-size to 55 in queue-id
1:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<qos-policies xmlns="urn:example:qos">
<name>my-policy</name>
<queue>
<queue-id>1</queue-id>
<maximum-burst-size>55</maximum-burst-size>
</queue>
</qos-policies>
</config>
</edit-config>
</rpc>
Then, the configuration of qos-policies is present in <operational>
as follows:
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<qos-policies xmlns="urn:example:qos"
xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<name>my-policy</name>
<queue>
<queue-id>1</queue-id>
<maximum-burst-size>55</maximum-burst-size>
</queue>
<queue or:origin="or:system">
<queue-id>2</queue-id>
<maximum-burst-size>60</maximum-burst-size>
</queue>
<queue or:origin="or:system">
<queue-id>3</queue-id>
<maximum-burst-size>70</maximum-burst-size>
</queue>
<queue or:origin="or:system">
<queue-id>4</queue-id>
<maximum-burst-size>80</maximum-burst-size>
</queue>
</qos-policies>
5.5.4. Configuring Descendant Nodes of a System-defined Node
This subsection also uses the fictional interface YANG module defined
in Appendix C.3 of [RFC8342]. Suppose the system provides a loopback
interface (named "lo0") with a default IPv4 address of "127.0.0.1"
and a default IPv6 address of "::1".
The configuration of "lo0" interface is present in <system> as
follows:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
The configuration of "lo0" interface is present in <operational> as
follows:
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<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:system">
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
Later on, the client further configures the description node of a
"lo0" interface as follows:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<interfaces>
<interface>
<name>lo0</name>
<description>loopback</description>
</interface>
</interfaces>
</config>
</edit-config>
</rpc>
Then the configuration of interface "lo0" is present in <operational>
as follows:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<interface>
<name>lo0</name>
<description>loopback</description>
<ip-address or:origin="or:system">127.0.0.1</ip-address>
<ip-address or:origin="or:system">::1</ip-address>
</interface>
</interfaces>
6. The "ietf-system-datastore" Module
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6.1. Data Model Overview
This YANG module defines a new YANG identity named "system" that uses
the "ds:datastore" identity defined in [RFC8342]. A client can
discover the <system> datastore support on the server by reading the
YANG library information from the operational state datastore. Note
that no new origin identity is defined in this document, the
"or:system" origin Metadata Annotation [RFC7952] is used to indicate
the origin of a data item is system. Support for the "origin"
annotation is identified with the feature "origin" defined in
[RFC8526].
The following diagram illustrates the relationship amongst the
"identity" statements defined in the "ietf-system-datastore" and
"ietf-datastores" YANG modules:
Identities:
+--- datastore
| +--- conventional
| | +--- running
| | +--- candidate
| | +--- startup
| | +--- system
| | +--- intended
| +--- dynamic
| +--- operational
The diagram above uses syntax that is similar to but not defined in [RFC8340].
6.2. Example Usage
This section gives an example of data retrieval from <system>. The
YANG module used are shown in Appendix C.2 of [RFC8342]. All the
messages are presented in a protocol-independent manner. JSON is
used only for its conciseness.
Suppose the following data is added to <running>:
{
"bgp": {
"local-as": "64501",
"peer-as": "64502",
"peer": {
"name": "2001:db8::2:3"
}
}
}
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REQUEST (a <get-data> or GET request sent from the NETCONF or
RESTCONF client):
Datastore: <system>
Target:/bgp
An example of RESTCONF request:
GET /restconf/ds/system/bgp HTTP/1.1
Host: example.com
Accept: application/yang-data+xml
RESPONSE ("local-port" leaf value is supplied by the system):
{
"bgp": {
"peer": {
"name": "2001:db8::2:3",
"local-port": "60794"
}
}
}
6.3. YANG Module
<CODE BEGINS> file "ietf-system-datastore@2023-01-05.yang"
module ietf-system-datastore {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-system-datastore";
prefix sysds;
import ietf-datastores {
prefix ds;
reference
"RFC 8342: Network Management Datastore Architecture(NMDA)";
}
organization
"IETF NETDOD (Network Modeling) Working Group";
contact
"WG Web: https://datatracker.ietf.org/wg/netmod/
WG List: NETMOD WG list <mailto:netmod@ietf.org>
Author: Qiufang Ma
<mailto:maqiufang1@huawei.com>
Author: Qin Wu
<mailto:bill.wu@huawei.com>
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Author: Chong Feng
<mailto:frank.fengchong@huawei.com>";
description
"This module defines a new YANG identity that uses the
ds:datastore identity defined in [RFC8342].
Copyright (c) 2022 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC HHHH
(https://www.rfc-editor.org/info/rfcHHHH); see the RFC
itself for full legal notices.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.";
revision 2023-01-05 {
description
"Initial version.";
reference
"RFC XXXX: System-defined Configuration";
}
identity system {
base ds:conventional;
description
"This read-only datastore contains the configuration
provided by the system itself.";
}
}
<CODE ENDS>
7. The "ietf-netconf-resolve-system" Module
This YANG module is optional to implement.
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7.1. Data Model Overview
This YANG module augments NETCONF <edit-config>, <edit-data> and
<copy-config> operations with a new parameter "resolve-system" in the
input parameters. If the "resolve-system" parameter is present, the
server will copy the referenced system configuration into target
datastore automatically. A NETCONF client can discover the "resolve-
system" parameter support on the server by checking the YANG library
information with "ietf-netconf-resolve-system" YANG module included
from the operational state datastore.
The following tree diagram [RFC8340] illustrates the "ietf-netconf-
resolve-system" module:
module: ietf-netconf-resolve-system
augment /nc:edit-config/nc:input:
+---w resolve-system? empty
augment /nc:copy-config/nc:input:
+---w resolve-system? empty
augment /ncds:edit-data/ncds:input:
+---w resolve-system? empty
The following tree diagram [RFC8340] illustrates "edit-config",
"copy-config" and "edit-data" rpcs defined in "ietf-netconf" and
"ietf-netconf-nmda" respectively, augmented by "ietf-netconf-resolve-
system" YANG module:
rpcs:
+---x edit-config
| +---w input
| +---w target
| | +---w (config-target)
| | +--:(candidate)
| | | +---w candidate? empty {candidate}?
| | +--:(running)
| | +---w running? empty {writable-running}?
| +---w default-operation? enumeration
| +---w test-option? enumeration {validate}?
| +---w error-option? enumeration
| +---w (edit-content)
| | +--:(config)
| | | +---w config? <anyxml>
| | +--:(url)
| | +---w url? inet:uri {url}?
| +---w resolve-system? empty
+---x copy-config
| +---w input
| +---w target
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| | +---w (config-target)
| | +--:(candidate)
| | | +---w candidate? empty {candidate}?
| | +--:(running)
| | | +---w running? empty {writable-running}?
| | +--:(startup)
| | | +---w startup? empty {startup}?
| | +--:(url)
| | +---w url? inet:uri {url}?
| +---w source
| | +---w (config-source)
| | +--:(candidate)
| | | +---w candidate? empty {candidate}?
| | +--:(running)
| | | +---w running? empty
| | +--:(startup)
| | | +---w startup? empty {startup}?
| | +--:(url)
| | | +---w url? inet:uri {url}?
| | +--:(config)
| | +---w config? <anyxml>
| +---w resolve-system? empty
+---x edit-data
+---w input
+---w datastore ds:datastore-ref
+---w default-operation? enumeration
+---w (edit-content)
| +--:(config)
| | +---w config? <anydata>
| +--:(url)
| +---w url? inet:uri {nc:url}?
+---w resolve-system? empty
7.2. Example Usage
This section gives an example of an <edit-config> request to
reference system-defined data nodes which are not present in
<running> with a "resolve-system" parameter. A retrieval of
<running> to show the auto-copied referenced system configurations
after the <edit-config> request is also given. The YANG module used
is shown as follows, leafrefs refer to an existing name and address
of an interface:
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module example-interface-management {
yang-version 1.1;
namespace "urn:example:interfacemgmt";
prefix "inm";
container interfaces {
list interface {
key name;
leaf name {
type string;
}
leaf description {
type string;
}
leaf mtu {
type uint16;
}
leaf ip-address {
type inet:ip-address;
}
}
}
container default-address {
leaf ifname {
type leafref {
path "../../interfaces/interface/name";
}
}
leaf address {
type leafref {
path "../../interfaces/interface[name = current()/../ifname]"
+ "/ip-address";
}
}
}
}
Image that the system provides a loopback interface (named "lo0")
with a predefined MTU value of "1500" and a predefined IP address of
"127.0.0.1". The <system> datastore shows the following
configuration of loopback interface:
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<interfaces xmlns="urn:example:interfacemgmt">
<interface>
<name>lo0</name>
<mtu>1500</mtu>
<ip-address>127.0.0.1</ip-address>
</interface>
</interfaces>
The client sends an <edit-config> operation to add the configuration
of default-address with a "resolve-system" parameter:
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="101">
<edit-config>
<target>
<running/>
</target>
<config>
<default-address xmlns="urn:example:interfacemgmt">
<if-name>lo0</if-name>
<address>127.0.0.1</address>
</default-address>
</config>
<resolve-system/>
</edit-config>
</rpc>
Since the "resolve-system" parameter is provided, the server will
resolve any leafrefs to system configurations and copy the referenced
system-defined nodes into <running> automatically with the same value
(i.e., the name and ip-address data nodes of lo0 interface) in
<system> at the end of <edit-config> operation constraint
enforcement. After the processing, a positive response is returned:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<ok/>
</rpc-reply>
Then the client sends a <get-config> operation towards <running>:
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<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
<source>
<running/>
</source>
<filter type="subtree">
<interfaces xmlns="urn:example:interfacemgmt"/>
</filter>
</get-config>
</rpc>
Given that the referenced interface "name" and "ip-address" of lo0
are configured by the server, the following response is returned:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data>
<interfaces xmlns="urn:example:interfacemgmt">
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
</interface>
</interfaces>
</data>
</rpc-reply>
7.3. YANG Module
<CODE BEGINS> file "ietf-netconf-resolve-system@2023-01-05.yang"
=============== NOTE: '\' line wrapping per RFC 8792 ================
module ietf-netconf-resolve-system {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-resolve-system";
prefix ncrs;
import ietf-netconf {
prefix nc;
reference
"RFC 6241: Network Configuration Protocol (NETCONF)";
}
import ietf-netconf-nmda {
prefix ncds;
reference
"RFC 8526: NETCONF Extensions to Support the Network
Management Datastore Architecture";
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}
organization
"IETF NETMOD (Network Modeling) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
Author: Qiufang Ma
<mailto:maqiufang1@huawei.com>
Author: Qin Wu
<mailto:bill.wu@huawei.com>
Author: Chong Feng
<mailto:frank.fengchong@huawei.com>";
description
"This module defines an extension to the NETCONF protocol
that allows the NETCONF client to control whether the server
is allowed to copy referenced system configuration
automatically without the client doing so explicitly.
Copyright (c) 2022 IETF Trust and the persons identified
as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC HHHH
(https://www.rfc-editor.org/info/rfcHHHH); see the RFC
itself for full legal notices.
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 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.";
revision 2023-01-05 {
description
"Initial version.";
reference
"RFC XXXX: System-defined Configuration";
}
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grouping resolve-system-grouping {
description
"Define the resolve-system parameter grouping.";
leaf resolve-system {
type empty;
description
"When present, the server is allowed to automatically
configure referenced system configuration into the
target configuration datastore.";
}
}
augment "/nc:edit-config/nc:input" {
description
"Allows the server to automatically configure
referenced system configuration to make configuration
valid.";
uses resolve-system-grouping;
}
augment "/nc:copy-config/nc:input" {
description
"Allows the server to automatically configure
referenced system configuration to make configuration
valid.";
uses resolve-system-grouping;
}
augment "/ncds:edit-data/ncds:input" {
description
"Allows the server to automatically configure
referenced system configuration to make configuration
valid.";
uses resolve-system-grouping;
}
}
<CODE ENDS>
8. IANA Considerations
8.1. The "IETF XML" Registry
This document registers two XML namespace URNs in the 'IETF XML
registry', following the format defined in [RFC3688].
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URI: urn:ietf:params:xml:ns:yang:ietf-system-datastore
Registrant Contact: The IESG.
XML: N/A, the requested URIs are XML namespaces.
URI: urn:ietf:params:xml:ns:yang:ietf-netconf-resolve-system
Registrant Contact: The IESG.
XML: N/A, the requested URIs are XML namespaces.
8.2. The "YANG Module Names" Registry
This document registers two module names in the 'YANG Module Names'
registry, defined in [RFC6020] .
name: ietf-system-datastore
prefix: sys
namespace: urn:ietf:params:xml:ns:yang:ietf-system-datatstore
maintained by IANA: N
RFC: XXXX // RFC Ed.: replace XXXX and remove this comment
name: ietf-netconf-resolve-system
prefix: ncrs
namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-resolve-system
maintained by IANA: N
RFC: XXXX // RFC Ed.: replace XXXX and remove this comment
8.3. RESTCONF Capability URN Registry
This document registers a capability in the "RESTCONF Capability
URNs" registry [RFC8040]:
Index Capability Identifier
-----------------------------------------------------------------------
:resolve-system urn:ietf:params:restconf:capability:resolve-system:1.0
9. Security Considerations
9.1. Regarding the "ietf-system-datastore" YANG Module
The YANG module defined in this document extends the base operations
for NETCONF [RFC6241] and RESTCONF [RFC8040]. The lowest NETCONF
layer is the secure transport layer, and the mandatory-to-implement
secure transport is Secure Shell (SSH) [RFC6242]. The lowest
RESTCONF layer is HTTPS, and the mandatory-to-implement secure
transport is TLS [RFC8446].
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The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF users to
a preconfigured subset of all available NETCONF protocol operations
and content.
9.2. Regarding the "ietf-netconf-resolve-system" YANG Module
The YANG module defined in this document extends the base operations
for NETCONF [RFC6241] and [RFC8526]. The lowest NETCONF layer is the
secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF users to
a preconfigured subset of all available NETCONF protocol operations
and content.
The security considerations for the base NETCONF protocol operations
(see Section 9 of [RFC6241] apply to the new extended RPC operations
defined in this document.
10. Contributors
Kent Watsen
Watsen Networks
Email: kent+ietf@watsen.net
Jan Lindblad
Cisco Systems
Email: jlindbla@cisco.com
Chongfeng Xie
China Telecom
Beijing
China
Email: xiechf@chinatelecom.cn
Jason Sterne
Nokia
Email: jason.sterne@nokia.com
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Acknowledgements
The authors would like to thank for following for discussions and
providing input to this document (ordered by first name): Alex Clemm,
Andy Bierman, Balazs Lengyel, Juergen Schoenwaelder, Martin
Bjorklund, Mohamed Boucadair, Robert Wilton and Timothy Carey.
References
Normative References
[RFC2119] Bradner, S. and RFC Publisher, "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.,
Bierman, A., Ed., and RFC Publisher, "Network
Configuration Protocol (NETCONF)", RFC 6241,
DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6470] Bierman, A. and RFC Publisher, "Network Configuration
Protocol (NETCONF) Base Notifications", RFC 6470,
DOI 10.17487/RFC6470, February 2012,
<https://www.rfc-editor.org/info/rfc6470>.
[RFC7950] Bjorklund, M., Ed. and RFC Publisher, "The YANG 1.1 Data
Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August
2016, <https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., Watsen, K., and RFC Publisher,
"RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040,
January 2017, <https://www.rfc-editor.org/info/rfc8040>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
Wilton, R., and RFC Publisher, "Network Management
Datastore Architecture (NMDA)", RFC 8342,
DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8526] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
Wilton, R., and RFC Publisher, "NETCONF Extensions to
Support the Network Management Datastore Architecture",
RFC 8526, DOI 10.17487/RFC8526, March 2019,
<https://www.rfc-editor.org/info/rfc8526>.
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[RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
E., Tripathy, A., and RFC Publisher, "Subscription to YANG
Notifications", RFC 8639, DOI 10.17487/RFC8639, September
2019, <https://www.rfc-editor.org/info/rfc8639>.
[RFC8641] Clemm, A., Voit, E., and RFC Publisher, "Subscription to
YANG Notifications for Datastore Updates", RFC 8641,
DOI 10.17487/RFC8641, September 2019,
<https://www.rfc-editor.org/info/rfc8641>.
Informative References
[I-D.ma-netmod-immutable-flag]
Ma, Q., Wu, Q., Lengyel, B., and H. Li, "YANG Extension
and Metadata Annotation for Immutable Flag", Work in
Progress, Internet-Draft, draft-ma-netmod-immutable-flag-
04, 20 October 2022,
<https://datatracker.ietf.org/doc/html/draft-ma-netmod-
immutable-flag-04>.
[RFC7317] Bierman, A., Bjorklund, M., and RFC Publisher, "A YANG
Data Model for System Management", RFC 7317,
DOI 10.17487/RFC7317, August 2014,
<https://www.rfc-editor.org/info/rfc7317>.
[RFC8174] Leiba, B. and RFC Publisher, "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>.
[RFC8407] Bierman, A. and RFC Publisher, "Guidelines for Authors and
Reviewers of Documents Containing YANG Data Models",
BCP 216, RFC 8407, DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/info/rfc8407>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
Wilton, R., and RFC Publisher, "YANG Library", RFC 8525,
DOI 10.17487/RFC8525, March 2019,
<https://www.rfc-editor.org/info/rfc8525>.
[RFC8808] Wu, Q., Lengyel, B., Niu, Y., and RFC Publisher, "A YANG
Data Model for Factory Default Settings", RFC 8808,
DOI 10.17487/RFC8808, August 2020,
<https://www.rfc-editor.org/info/rfc8808>.
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Appendix A. Key Use Cases
Following provides three use cases related to system-defined
configuration lifecycle management. The simple interface data model
defined in Appendix C.3 of [RFC8342] is used. For each use case,
snippets of <running>, <system>, <intended> and <operational> are
shown.
A.1. Device Powers On
<running>:
No configuration for "lo0" appears in <running>;
<system>:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
<intended>:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
<operational>:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:system">
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
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A.2. Client Commits Configuration
If a client creates an interface "et-0/0/0" but the interface does
not physically exist at this point:
<running>:
<interfaces>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
</interface>
</interfaces>
<system>:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
<intended>:
<interfaces>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
</interface>
<interface>
</interfaces>
<operational>:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<interface or:origin="or:system">
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
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A.3. Operator Installs Card into a Chassis
<running>:
<interfaces>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
</interface>
</interfaces>
<system>:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<mtu>1500</mtu>
</interface>
</interfaces>
<intended>:
<interfaces>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
<mtu>1500</mtu>
</interface>
<interface>
</interfaces>
<operational>:
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<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<interface or:origin="or:system">
<name or:origin>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
<mtu or:origin="or:system">1500</mtu>
</interface>
<interface>
</interfaces>
Appendix B. Changes between Revisions
v00 - v01
* Clarify why client's explicit copy is not preferred but cannot be
avoided if resolve-system parameter is not defined
* Clarify active system configuration
* Update the timing when the server's auto copy should be enforced
if a resolve-system parameter is used
* Editorial changes
Appendix C. Open Issues tracking
* Should the "with-origin" parameter be supported for <intended>?
Authors' Addresses
Qiufang Ma (editor)
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: maqiufang1@huawei.com
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Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: bill.wu@huawei.com
Feng Chong
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: frank.fengchong@huawei.com
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