NETCONF Working Group K. Watsen
Internet-Draft Watsen Networks
Intended status: Standards Track 24 April 2025
Expires: 26 October 2025
A YANG Data Model for RESTCONF Clients and Servers
draft-ietf-netconf-restconf-client-server-43
Abstract
This document presents two YANG modules, one module to configure a
RESTCONF client and the other module to configure a RESTCONF server.
These modules support both standard and call home RESTCONF
connections. For initiating connections, both modules configure
HTTPS. For listening for connections, both modules configure HTTPS
and HTTP. Whilst RESTCONF supports only HTTPS, HTTP may be
configured for when a TLS-terminator is deployed in front of the
listener.
Editorial Note (To be removed by RFC Editor)
This draft contains placeholder values that need to be replaced with
finalized values at the time of publication. This note summarizes
all of the substitutions that are needed. No other RFC Editor
instructions are specified elsewhere in this document.
Artwork in this document contains shorthand references to drafts in
progress. Please apply the following replacements (note: not all may
be present):
* GGGG --> the assigned RFC value for draft-ietf-netconf-http-
client-server
* HHHH --> the assigned RFC value for draft-ietf-netconf-netconf-
client-server
* IIII --> the assigned RFC value for this draft
* JJJJ --> the assigned RFC value for draft-ietf-netconf-udp-client-
server
Artwork in this document contains placeholder values for the date of
publication of this draft. Please apply the following replacement:
* 2025-04-24 --> the publication date of this draft
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The "Relation to other RFCs" section Section 1.1 contains the text
"one or more YANG modules" and, later, "modules". This text is
sourced from a file in a context where it is unknown how many modules
a draft defines. The text is not wrong as is, but it may be improved
by stating more directly how many modules are defined.
The "Relation to other RFCs" section Section 1.1 contains a self-
reference to this draft, along with a corresponding reference in the
Appendix. Please replace the self-reference in this section with
"This RFC" (or similar) and remove the self-reference in the
"Normative/Informative References" section, whichever it is in.
Tree-diagrams in this draft may use the '\' line-folding mode defined
in RFC 8792. However, nicer-to-the-eye is when the '\\' line-folding
mode is used. The AD suggested suggested putting a request here for
the RFC Editor to help convert "ugly" '\' folded examples to use the
'\\' folding mode. "Help convert" may be interpreted as, identify
what looks ugly and ask the authors to make the adjustment.
Due to a bug in the pyang tool used to create tree diagrams, some
"key" nodes appear as optional (i.e., have a '?' postfix). Ideally
the '?' character is removed in the tree diagrams for "key" nodes.
Recipe: search for lists using the string "* [", then note the nodes
appearing in the square brackets (e.g., "* [name]"), then look for
matching child nodes and remove the '?' characters (e.g., "name?"
becomes "name").
The following Appendix section is to be removed prior to publication:
* Appendix A. Change Log
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 26 October 2025.
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Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Relation to other RFCs . . . . . . . . . . . . . . . . . 5
1.2. Specification Language . . . . . . . . . . . . . . . . . 6
1.3. Adherence to the NMDA . . . . . . . . . . . . . . . . . . 6
2. The "ietf-restconf-client" Module . . . . . . . . . . . . . . 6
2.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 7
2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 10
2.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 14
3. The "ietf-restconf-server" Module . . . . . . . . . . . . . . 24
3.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 24
3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 29
3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 35
4. Security Considerations . . . . . . . . . . . . . . . . . . . 49
4.1. Considerations for the "ietf-restconf-client" YANG
Module . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.2. Considerations for the "ietf-restconf-server" YANG
Module . . . . . . . . . . . . . . . . . . . . . . . . . 50
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 51
5.1. The "IETF XML" Registry . . . . . . . . . . . . . . . . . 51
5.2. The "YANG Module Names" Registry . . . . . . . . . . . . 51
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.1. Normative References . . . . . . . . . . . . . . . . . . 51
6.2. Informative References . . . . . . . . . . . . . . . . . 53
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 54
A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 54
A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 54
A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 54
A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 55
A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 55
A.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 55
A.7. 06 to 07 . . . . . . . . . . . . . . . . . . . . . . . . 55
A.8. 07 to 08 . . . . . . . . . . . . . . . . . . . . . . . . 56
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A.9. 08 to 09 . . . . . . . . . . . . . . . . . . . . . . . . 56
A.10. 09 to 10 . . . . . . . . . . . . . . . . . . . . . . . . 56
A.11. 10 to 11 . . . . . . . . . . . . . . . . . . . . . . . . 56
A.12. 11 to 12 . . . . . . . . . . . . . . . . . . . . . . . . 56
A.13. 12 to 13 . . . . . . . . . . . . . . . . . . . . . . . . 57
A.14. 13 to 14 . . . . . . . . . . . . . . . . . . . . . . . . 57
A.15. 14 to 15 . . . . . . . . . . . . . . . . . . . . . . . . 57
A.16. 15 to 16 . . . . . . . . . . . . . . . . . . . . . . . . 58
A.17. 16 to 17 . . . . . . . . . . . . . . . . . . . . . . . . 58
A.18. 17 to 18 . . . . . . . . . . . . . . . . . . . . . . . . 58
A.19. 18 to 19 . . . . . . . . . . . . . . . . . . . . . . . . 58
A.20. 19 to 20 . . . . . . . . . . . . . . . . . . . . . . . . 58
A.21. 20 to 21 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.22. 21 to 22 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.23. 22 to 23 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.24. 23 to 24 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.25. 24 to 25 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.26. 25 to 26 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.27. 26 to 27 . . . . . . . . . . . . . . . . . . . . . . . . 59
A.28. 27 to 28 . . . . . . . . . . . . . . . . . . . . . . . . 60
A.29. 28 to 29 . . . . . . . . . . . . . . . . . . . . . . . . 60
A.30. 29 to 30 . . . . . . . . . . . . . . . . . . . . . . . . 60
A.31. 30 to 31 . . . . . . . . . . . . . . . . . . . . . . . . 60
A.32. 31 to 32 . . . . . . . . . . . . . . . . . . . . . . . . 60
A.33. 32 to 34 . . . . . . . . . . . . . . . . . . . . . . . . 60
A.34. 34 to 36 . . . . . . . . . . . . . . . . . . . . . . . . 61
A.35. 38 to 39 . . . . . . . . . . . . . . . . . . . . . . . . 61
A.36. 39 to 40 . . . . . . . . . . . . . . . . . . . . . . . . 61
A.37. 40 to 41 . . . . . . . . . . . . . . . . . . . . . . . . 61
A.38. 41 to 42 . . . . . . . . . . . . . . . . . . . . . . . . 61
A.39. 42 to 43 . . . . . . . . . . . . . . . . . . . . . . . . 62
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 62
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 62
1. Introduction
This document presents two YANG [RFC7950] modules, one module to
configure a RESTCONF client and the other module to configure a
RESTCONF server. These modules support both standard [RFC8040] and
Call Home [RFC8071] RESTCONF connections.
For initiating connections, both modules configure HTTPS, whether by
using TLS [RFC8446] or QUIC [RFC9000]. For when listening for
connections, both modules configure HTTPS and HTTP, where HTTP is
used when a TLS-terminator is deployed in front of the listener.
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1.1. Relation to other RFCs
This document presents one or more YANG modules [RFC7950] that are
part of a collection of RFCs that work together to, ultimately,
support the configuration of both the clients and servers of both the
NETCONF [RFC6241] and RESTCONF [RFC8040] protocols.
Primary dependency relationships between the YANG groupings defined
in the various RFCs is presented in the below diagram. In some
cases, a draft may define secondary groupings that introduce
dependencies not illustrated in the diagram. The labels in the
diagram are a shorthand name for the defining RFC. The citation
reference for shorthand name is provided below the diagram.
Please note that the arrows in the diagram point from referencer to
referenced. For example, the "crypto-types" RFC does not have any
dependencies, whilst the "keystore" RFC depends on the "crypto-types"
RFC.
crypto-types
^ ^
/ \
/ \
truststore keystore
^ ^ ^ ^
| +---------+ | |
| | | |
| +------------+ |
tcp-client-server | / | |
^ ^ ssh-client-server | |
| | ^ tls-client-server
| | | ^ ^ http-client-server
| | | | | ^
| | | +-----+ +---------+ |
| | | | | |
| +-----------|--------|--------------+ | |
| | | | | |
+-----------+ | | | | |
| | | | | |
| | | | | |
netconf-client-server restconf-client-server
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+======================+===========================================+
|Label in Diagram | Originating RFC |
+======================+===========================================+
|crypto-types | [RFC9640] |
+----------------------+-------------------------------------------+
|truststore | [RFC9641] |
+----------------------+-------------------------------------------+
|keystore | [RFC9642] |
+----------------------+-------------------------------------------+
|tcp-client-server | [RFC9643] |
+----------------------+-------------------------------------------+
|ssh-client-server | [RFC9644] |
+----------------------+-------------------------------------------+
|tls-client-server | [RFC9645] |
+----------------------+-------------------------------------------+
|http-client-server | [I-D.ietf-netconf-http-client-server] |
+----------------------+-------------------------------------------+
|netconf-client-server | [I-D.ietf-netconf-netconf-client-server] |
+----------------------+-------------------------------------------+
|restconf-client-server| [I-D.ietf-netconf-restconf-client-server] |
+----------------------+-------------------------------------------+
Table 1: Label in Diagram to RFC Mapping
1.2. Specification 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. Adherence to the NMDA
This document is compliant with the Network Management Datastore
Architecture (NMDA) [RFC8342]. For instance, as described in
[RFC9641] and [RFC9642], trust anchors and keys installed during
manufacturing are expected to appear in <operational> (Section 5.3 of
[RFC8342]), and <system> [I-D.ietf-netmod-system-config], if
implemented.
2. The "ietf-restconf-client" Module
The RESTCONF client data model presented in this section supports
both clients initiating connections to servers, as well as clients
listening for connections from servers calling home.
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YANG feature statements are used to enable implementations to
advertise which potentially uncommon parts of the data model the
RESTCONF client supports.
2.1. Data Model Overview
This section provides an overview of the "ietf-restconf-client"
module in terms of its features and groupings.
2.1.1. Features
The following diagram lists all the "feature" statements defined in
the "ietf-restconf-client" module:
Features:
+-- https-initiate
+-- http-listen
+-- https-listen
+-- central-restconf-client-supported
The diagram above uses syntax that is similar to but not defined in
[RFC8340].
2.1.2. Groupings
The "ietf-restconf-client" module defines the following "grouping"
statements:
* restconf-client-initiate-stack-grouping
* restconf-client-listen-stack-grouping
* restconf-client-app-grouping
Each of these groupings are presented in the following subsections.
2.1.2.1. The "restconf-client-initiate-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
client-initiate-stack-grouping" grouping:
grouping restconf-client-initiate-stack-grouping:
+-- http-client-parameters
| +---u httpc:http-client-grouping
+-- restconf-client-parameters
+---u rcc:restconf-client-grouping
Comments:
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* The "restconf-client-initiate-stack-grouping" defines the
configuration for a full RESTCONF protocol stack, for RESTCONF
clients that initiate connections to RESTCONF servers, as opposed
to receiving call-home [RFC8071] connections.
* The "transport" choice node enables transport options to be
configured. This document only defines an "https" option, but
other options MAY be augmented in.
* For the referenced grouping statement(s):
- The "tcp-client-grouping" grouping is discussed in
Section 3.1.2.1 of [RFC9643].
- The "tls-client-grouping" grouping is discussed in
Section 3.1.2.1 of [RFC9645].
- The "http-client-grouping" grouping is discussed in
Section 2.1.2.2 of [I-D.ietf-netconf-http-client-server].
2.1.2.2. The "restconf-client-listen-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
client-listen-stack-grouping" grouping:
grouping restconf-client-listen-stack-grouping:
+-- (transport)
+--:(tcp) {tcp-listen}?
+-- tcp
+-- tcp-server-parameters
| +---u tcps:tcp-server-grouping
+-- http-client-parameters
| +---u httpc:http-client-grouping
+-- restconf-client-parameters
+---u rcc:restconf-client-grouping
Comments:
* The "restconf-client-listen-stack-grouping" defines the
configuration for a full RESTCONF protocol stack, for RESTCONF
clients that receive call-home [RFC8071] connections from RESTCONF
servers.
* The "transport" choice node enables either the HTTP or HTTPS
transports to be configured, with each option enabled by a
"feature" statement. Whilst RESTCONF [RFC8040] requires HTTPS, an
HTTP option is provided to support cases where a TLS-terminator is
deployed in front of the RESTCONF-client.
* For the referenced grouping statement(s):
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- The "tcp-server-grouping" grouping is discussed in
Section 4.1.2.1 of [RFC9643].
- The "tls-client-grouping" grouping is discussed in
Section 3.1.2.1 of [RFC9645].
- The "http-client-grouping" grouping is discussed in
Section 2.1.2.2 of [I-D.ietf-netconf-http-client-server].
2.1.2.3. The "restconf-client-app-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
client-app-grouping" grouping:
grouping restconf-client-app-grouping:
+-- initiate! {initiate}?
| +-- restconf-server* [name]
| +-- name? string
| +-- endpoints
| | +-- endpoint* [name]
| | +-- name? string
| | +---u restconf-client-initiate-stack-grouping
| +-- connection-type
| | +-- (connection-type)
| | +--:(persistent-connection)
| | | +-- persistent!
| | +--:(periodic-connection)
| | +-- periodic!
| | +-- period? uint16
| | +-- anchor-time? yang:date-and-time
| | +-- idle-timeout? uint16
| +-- reconnect-strategy
| +-- start-with? enumeration
| +-- max-wait? uint16
| +-- max-attempts? uint8
+-- listen! {listen}?
+-- idle-timeout? uint16
+-- endpoints
+-- endpoint* [name]
+-- name? string
+---u restconf-client-listen-stack-grouping
Comments:
* The "restconf-client-app-grouping" defines the configuration for a
RESTCONF client that supports both initiating connections to
RESTCONF servers as well as receiving call-home connections from
RESTCONF servers.
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* Both the "initiate" and "listen" subtrees are predicated by
"feature" statements.
* For the referenced grouping statement(s):
- The "restconf-client-initiate-stack-grouping" grouping is
discussed in Section 2.1.2.1 in this document.
- The "restconf-client-listen-stack-grouping" grouping is
discussed in Section 2.1.2.2 in this document.
2.1.3. Protocol-accessible Nodes
The following tree diagram [RFC8340] lists all the protocol-
accessible nodes defined in the "ietf-restconf-client" module:
module: ietf-restconf-client
+--rw restconf-client {central-restconf-client-supported}?
+---u restconf-client-app-grouping
Comments:
* Protocol-accessible nodes are those nodes that are accessible when
the module is "implemented", as described in Section 5.6.5 of
[RFC7950].
* The top-level node "restconf-client" is additionally constrained
by the feature "central-restconf-client-supported".
* The "restconf-client-app-grouping" grouping is discussed in
Section 2.1.2.3 in this document.
* The reason for why "restconf-client-app-grouping" exists separate
from the protocol-accessible nodes definition is so as to enable
instances of restconf-client-app-grouping to be instantiated in
other locations, as may be needed or desired by some modules.
2.2. Example Usage
The following example illustrates configuring a RESTCONF client to
initiate connections, as well as to listen for call-home connections.
This example is consistent with the examples presented in
Section 2.2.1 of [RFC9641] and Section 2.2.1 of [RFC9642].
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=============== NOTE: '\' line wrapping per RFC 8792 ================
<restconf-client xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-cl\
ient">
<!-- RESTCONF servers to initiate connections to -->
<initiate>
<restconf-server>
<name>corp-fw1</name>
<endpoints>
<endpoint>
<name>corp-fw1.example.com</name>
<http-client-parameters>
<uri>
<scheme>https</scheme>
<authority>
<host>corp-fw1.example.com</host>
</authority>
</uri>
<tls-client-parameters>
<client-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-k\
ey>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</client-identity>
<server-authentication>
<ca-certs>
<central-truststore-reference>trusted-server-ca-ce\
rts</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-server-ee-ce\
rts</central-truststore-reference>
</ee-certs>
</server-authentication>
<keepalives>
<test-peer-aliveness>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</tls-client-parameters>
</http-client-parameters>
</endpoint>
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<endpoint>
<name>corp-fw2.example.com</name>
<http-client-parameters>
<uri>
<scheme>https</scheme>
<authority>
<host>corp-fw2.example.com</host>
</authority>
</uri>
<tls-client-parameters>
<client-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-k\
ey>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</client-identity>
<server-authentication>
<ca-certs>
<central-truststore-reference>trusted-server-ca-ce\
rts</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-server-ee-ce\
rts</central-truststore-reference>
</ee-certs>
</server-authentication>
<keepalives>
<test-peer-aliveness>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</tls-client-parameters>
</http-client-parameters>
</endpoint>
</endpoints>
<connection-type>
<persistent/>
</connection-type>
</restconf-server>
</initiate>
<!-- endpoints to listen for RESTCONF Call Home connections on -->
<listen>
<endpoints>
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<endpoint>
<name>Intranet-facing listener</name>
<tcp>
<tcp-server-parameters>
<local-bind>
<local-address>192.0.2.2</local-address>
</local-bind>
</tcp-server-parameters>
<http-client-parameters>
<uri>
<scheme>https</scheme>
<authority>
<host>corp-fw1.example.com</host>
</authority>
</uri>
<tls-client-parameters>
<client-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-k\
ey>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</client-identity>
<server-authentication>
<ca-certs>
<central-truststore-reference>trusted-server-ca-ce\
rts</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-server-ee-ce\
rts</central-truststore-reference>
</ee-certs>
</server-authentication>
<keepalives>
<peer-allowed-to-send/>
</keepalives>
</tls-client-parameters>
</http-client-parameters>
</tcp>
</endpoint>
</endpoints>
</listen>
</restconf-client>
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2.3. YANG Module
This YANG module has normative references to [RFC6991], [RFC8040],
and [RFC8071], [RFC9643], [RFC9645], and
[I-D.ietf-netconf-http-client-server].
<CODE BEGINS> file "ietf-restconf-client@2025-04-24.yang"
module ietf-restconf-client {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-client";
prefix rcc;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-tcp-server {
prefix tcps;
reference
"RFC DDDD: YANG Groupings for TCP Clients and TCP Servers";
}
import ietf-http-client {
prefix httpc;
reference
"RFC GGGG: YANG Groupings for HTTP Clients and HTTP Servers";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: https://datatracker.ietf.org/wg/netconf
WG List: NETCONF WG list <mailto:netconf@ietf.org>
Author: Kent Watsen <mailto:kent+ietf@watsen.net>";
description
"This module contains a collection of YANG definitions
for configuring RESTCONF clients.
Copyright (c) 2025 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
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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 IIII
(https://www.rfc-editor.org/info/rfcIIII); 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 2025-04-24 {
description
"Initial version";
reference
"RFC IIII: A YANG Data Model for RESTCONF Clients and Server";
}
// Features
feature initiate {
description
"The 'initiate' feature indicates that the RESTCONF
client supports initiating connections to RESTCONF
servers.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature listen {
description
"The 'listen' feature indicates that the RESTCONF client
supports listening for incoming RESTCONF server call-home
connections.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
feature tcp-listen {
if-feature listen;
description
"The 'tcp-listen' feature indicates that the RESTCONF client
supports listening for incoming RESTCONF server call-home
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connections over TCP (e.g., HTTP/1 or HTTP/2).";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
feature central-restconf-client-supported {
description
"The 'central-restconf-client-supported' feature indicates
that the server that implements this module supports
the top-level 'restconf-client' node.
This feature is needed as some servers may want to use
features defined in this module, which requires this
module to be implemented, without having to support
the top-level 'restconf-client' node.";
}
feature foo {
description
"This is an internal feature used only to create a
logical fallacy to remove unwanted nodes from the
'ietf-http-client' grouping.";
}
// Groupings
grouping restconf-client-grouping {
description
"A grouping for configuring a RESTCONF client without any
consideration for how underlying transport sessions are
established.
As no RESTCONF-specific client configuration needs to be
set, this node is empty, but retained for clarity and for
consistency with other 'client-server' models.";
}
grouping restconf-client-initiate-stack-grouping {
description
"A grouping for configuring a RESTCONF client
'initiate' protocol stack for a single outbound connection.";
container http-client-parameters {
description
"HTTP-level client parameters.";
uses httpc:http-client-grouping {
refine "uri/scheme" {
must '. = "https"';
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description
"RFC 8040 requires the 'https' scheme.";
}
refine 'uri/path' {
if-feature "foo and not foo"; // logically impossible
description
"The 'path' component of the URI does not make
sense to configure for a RESTCONF client.";
}
refine 'uri/query' {
if-feature "foo and not foo"; // logically impossible
description
"The 'query' component of the URI does not make
sense to configure for a RESTCONF client.";
}
refine 'uri/fragment' {
if-feature "foo and not foo"; // logically impossible
description
"The 'fragment' component of the URI does not make
sense to configure for a RESTCONF client.";
}
}
}
container restconf-client-parameters {
description
"RESTCONF-level client parameters to initiate
a RESTCONF over HTTP connection.";
uses rcc:restconf-client-grouping;
}
} // restconf-client-initiate-stack-grouping
grouping restconf-client-listen-stack-grouping {
description
"A grouping for configuring a RESTCONF client to listen
to a port for call home connections, as described in
RFC 8071.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
choice transport {
mandatory true;
description
"Selects between available transports.";
case tcp {
if-feature "tcp-listen";
container tcp {
description
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"Configures the client to open a TCP port to listen for
TCP-client connections, i.e., RESTCONF-server call home
connections.";
container tcp-server-parameters {
description
"TCP-level server parameters.";
uses tcps:tcp-server-grouping {
refine "local-bind/local-port" {
default "4336";
description
"The RESTCONF client will listen on the IANA-
assigned well-known port for 'restconf-ch-tls'
(4336) if no value is specified.";
}
}
}
container http-client-parameters {
description
"HTTP-level client parameters.";
uses httpc:http-client-grouping {
refine "uri/scheme" {
must '. = "https"';
description
"RFC 8040 requires the 'https' scheme.";
}
refine 'uri/authority/port' {
if-feature "foo and not foo"; // logically impossible
description
"The authority's 'port' component of the URI does
not make sense to configure for a RESTCONF client
listening for a call home connections.";
}
refine 'uri/path' {
if-feature "foo and not foo"; // logically impossible
description
"The 'path' component of the URI does not make
sense to configure for a RESTCONF client.";
}
refine 'uri/query' {
if-feature "foo and not foo"; // logically impossible
description
"The 'query' component of the URI does not make
sense to configure for a RESTCONF client.";
}
refine 'uri/fragment' {
if-feature "foo and not foo"; // logically impossible
description
"The 'fragment' component of the URI does not make
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sense to configure for a RESTCONF client.";
}
}
}
container restconf-client-parameters {
description
"RESTCONF-level client parameters.";
uses rcc:restconf-client-grouping;
}
}
}
}
} // restconf-client-listen-stack-grouping
grouping restconf-client-app-grouping {
description
"A grouping for configuring a RESTCONF client
application that supports both 'initiate' and 'listen'
protocol stacks for a multiplicity of connections.";
container initiate {
if-feature "initiate";
presence
"Indicates that client-initiated connections have been
configured. This statement is present so the mandatory
descendant nodes do not imply that this node must be
configured.";
description
"Configures client initiating underlying TCP connections.";
list restconf-server {
key "name";
min-elements 1;
description
"List of RESTCONF servers the RESTCONF client is to
maintain simultaneous connections with.";
leaf name {
type string;
description
"An arbitrary name for the RESTCONF server.";
}
container endpoints {
description
"Container for a list of endpoints.";
list endpoint {
key "name";
min-elements 1;
ordered-by user;
description
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"A non-empty user-ordered list of endpoints for this
RESTCONF client to try to connect to in sequence.
Defining more than one enables high-availability.";
leaf name {
type string;
description
"An arbitrary name for this endpoint.";
}
uses restconf-client-initiate-stack-grouping;
}
}
container connection-type {
description
"Indicates the RESTCONF client's preference for how
the RESTCONF connection is maintained.";
choice connection-type {
mandatory true;
description
"Selects between available connection types.";
case persistent-connection {
container persistent {
presence
"Indicates that a persistent connection is to be
maintained.";
description
"Maintain a persistent connection to the
RESTCONF server. If the connection goes down,
immediately start trying to reconnect to the
RESTCONF server, using the reconnection strategy.
This connection type minimizes any RESTCONF server
to RESTCONF client data-transfer delay, albeit
at the expense of holding resources longer.";
}
}
case periodic-connection {
container periodic {
presence
"Indicates that a periodic connection is to be
maintained.";
description
"Periodically connect to the RESTCONF server.
This connection type decreases resource
utilization, albeit with increased delay
in RESTCONF server to RESTCONF client
interactions.
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The RESTCONF client SHOULD gracefully close
the underlying TLS connection upon completing
planned activities.
Connections are established at the same start
time regardless how long the previous connection
stayed open.
In the case that the previous connection is
still active, establishing a new connection
is NOT RECOMMENDED.";
leaf period {
type uint16;
units "minutes";
default "60";
description
"Duration of time between periodic
connections.";
}
leaf anchor-time {
type yang:date-and-time {
// constrained to minute-level granularity
pattern '[0-9]{4}-(1[0-2]|0[1-9])-(0[1-9]|[1-2]'
+ '[0-9]|3[0-1])T(0[0-9]|1[0-9]|2[0-3]):['
+ '0-5][0-9]:00(Z|[\+\-]((1[0-3]|0[0-9]):'
+ '([0-5][0-9])|14:00))?';
}
description
"Designates a timestamp before or after which a
series of periodic connections are determined.
The periodic connections occur at a whole
multiple interval from the anchor time.
If an 'anchor-time' is not provided, then the
server MAY implicitly set it to the time when
this configuraton is applied (e.g., on boot).
For example, for an anchor time is 15 minutes
past midnight and a period interval of 24 hours,
then a periodic connection will occur 15 minutes
past midnight everyday.";
}
leaf idle-timeout {
type uint16;
units "seconds";
default "180"; // three minutes
description
"Specifies the maximum number of seconds
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that the underlying TCP session may remain
idle. A TCP session will be dropped if it
is idle for an interval longer than this
number of seconds If set to zero, then the
RESTCONF client will never drop a session
because it is idle.";
}
}
}
}
}
container reconnect-strategy {
description
"The reconnection strategy directs how a RESTCONF
client reconnects to a RESTCONF server, after
discovering its connection to the server has
dropped, even if due to a reboot. The RESTCONF
client starts with the specified endpoint and
tries to connect to it max-attempts times before
trying the next endpoint in the list (round
robin).";
leaf start-with {
type enumeration {
enum first-listed {
description
"Indicates that reconnections SHOULD start
with the first endpoint listed.";
}
enum last-connected {
description
"Indicates that reconnections SHOULD start with
the endpoint last connected to, if known. If
no previous connection is known, then the
first endpoint configured is used.";
}
enum random-selection {
description
"Indicates that reconnections SHOULD start with
a random endpoint.";
}
}
default "first-listed";
description
"Specifies which of the RESTCONF server's
endpoints the RESTCONF client SHOULD start
with when trying to connect to the RESTCONF
server.";
}
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leaf max-wait {
type uint16 {
range "1..max";
}
units "seconds";
default "5";
description
"Specifies the amount of time in seconds after which,
if the connection is not established, an endpoint
connection attempt is considered unsuccessful.";
}
leaf max-attempts {
type uint8 {
range "1..max";
}
default "3";
description
"Specifies the number times the RESTCONF client
tries to connect to a specific endpoint before
moving on to the next endpoint in the list
(round robin).";
}
}
}
} // initiate
container listen {
if-feature listen;
presence
"Indicates that client-listening ports have been configured.
This statement is present so the mandatory descendant nodes
do not imply that this node must be configured.";
description
"Configures the client to accept call-home TCP connections.";
leaf idle-timeout {
type uint16;
units "seconds";
default "180";
description
"Specifies the maximum number of seconds that an
underlying TCP session may remain idle. A TCP session
will be dropped if it is idle for an interval longer
then this number of seconds. If set to zero, then
the server will never drop a session because it is
idle.";
}
container endpoints {
description
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"Container for a list of endpoints.";
list endpoint {
key "name";
min-elements 1;
description
"List of endpoints to listen for RESTCONF connections.";
leaf name {
type string;
description
"An arbitrary name for the RESTCONF listen endpoint.";
}
uses restconf-client-listen-stack-grouping;
}
}
} // listen
} // restconf-client-app-grouping
// Protocol accessible node for servers that implement this module.
container restconf-client {
if-feature central-restconf-client-supported;
uses restconf-client-app-grouping;
description
"Top-level container for RESTCONF client configuration.";
}
}
<CODE ENDS>
3. The "ietf-restconf-server" Module
The RESTCONF server data model presented in this section supports
both listening for connections as well as initiating call-home
connections.
YANG feature statements are used to enable implementations to
advertise which potentially uncommon parts of the data model the
RESTCONF server supports.
3.1. Data Model Overview
This section provides an overview of the "ietf-restconf-server"
module in terms of its features and groupings.
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3.1.1. Features
The following diagram lists all the "feature" statements defined in
the "ietf-restconf-server" module:
Features:
+-- http-listen
+-- https-listen
+-- https-call-home
+-- central-restconf-server-supported
The diagram above uses syntax that is similar to but not defined in
[RFC8340].
3.1.2. Groupings
The "ietf-restconf-server" module defines the following "grouping"
statements:
* restconf-server-grouping
* restconf-server-listen-stack-grouping
* restconf-server-callhome-stack-grouping
* restconf-server-app-grouping
Each of these groupings are presented in the following subsections.
3.1.2.1. The "restconf-server-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
server-grouping" grouping:
grouping restconf-server-grouping:
+-- client-identity-mappings
+---u x509c2n:cert-to-name
Comments:
* The "restconf-server-grouping" defines the configuration for the
"RESTCONF" part of a protocol stack. It does not, for instance,
define any configuration for the "TCP", "TLS", or "HTTP" protocol
layers (for that, see Section 3.1.2.2 and Section 3.1.2.3).
* The "client-identity-mappings" node defines a mapping from
certificate fields to RESTCONF user names.
* For the referenced grouping statement(s):
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- The "cert-to-name" grouping is discussed in Section 4.1 of
[RFC7407].
3.1.2.2. The "restconf-server-listen-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
server-listen-stack-grouping" grouping:
grouping restconf-server-listen-stack-grouping:
+-- (transport)
+--:(http-over-tcp) {tcp-listen}?
| +-- http-over-tcp
| +-- external-endpoint!
| | +-- address inet:host
| | +-- port? inet:port-number
| | +-- trusted-proxy-count? uint8
| | +-- client-cert-var? string
| +-- tcp-server-parameters
| | +---u tcps:tcp-server-grouping
| +-- http-server-parameters
| | +---u https:http-server-grouping
| +-- restconf-server-parameters
| +---u rcs:restconf-server-grouping
+--:(http-over-tls) {tls-listen}?
| +-- http-over-tls
| +-- tcp-server-parameters
| | +---u tcps:tcp-server-grouping
| +-- tls-server-parameters
| | +---u tlss:tls-server-grouping
| +-- http-server-parameters
| | +---u https:http-server-grouping
| +-- restconf-server-parameters
| +---u rcs:restconf-server-grouping
+--:(http-over-quic) {quic-listen}?
+-- http-over-quic
+-- udp-server-parameters
| +---u udps:udp-server
+-- tls-server-parameters
| +---u tlss:tls-server-grouping
+-- http-server-parameters
| +---u https:http-server-grouping
+-- restconf-server-parameters
+---u rcs:restconf-server-grouping
Comments:
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* The "restconf-server-listen-stack-grouping" defines the
configuration for a full RESTCONF protocol stack for RESTCONF
servers that listen for connections from RESTCONF clients, as
opposed to initiating call-home [RFC8071] connections.
* The "transport" choice node enables either the HTTP or HTTPS
transports to be configured, with each option enabled by a
"feature" statement. The HTTP option is provided to support cases
where a TLS-terminator is deployed in front of the RESTCONF-
server.
* For the referenced grouping statement(s):
- The "tcp-server-grouping" grouping is discussed in
Section 4.1.2.1 of [RFC9643].
- The "tls-server-grouping" grouping is discussed in
Section 4.1.2.1 of [RFC9645].
- The "http-server-grouping" grouping is discussed in
Section 3.1.2.1 of [I-D.ietf-netconf-http-client-server].
- The "restconf-server-grouping" is discussed in Section 3.1.2.1
of this document.
3.1.2.3. The "restconf-server-callhome-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
server-callhome-stack-grouping" grouping:
grouping restconf-server-callhome-stack-grouping:
+-- (transport)
+--:(http-over-tls) {tls-callhome}?
+-- http-over-tls
+-- tcp-client-parameters
| +---u tcpc:tcp-client-grouping
+-- tls-server-parameters
| +---u tlss:tls-server-grouping
+-- http-server-parameters
| +---u https:http-server-grouping
+-- restconf-server-parameters
+---u rcs:restconf-server-grouping
Comments:
* The "restconf-server-callhome-stack-grouping" defines the
configuration for a full RESTCONF protocol stack, for RESTCONF
servers that initiate call-home [RFC8071] connections to RESTCONF
clients.
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* The "transport" choice node enables transport options to be
configured. This document only defines an "https" option, but
other options MAY be augmented in.
* For the referenced grouping statement(s):
- The "tcp-client-grouping" grouping is discussed in
Section 3.1.2.1 of [RFC9643].
- The "tls-server-grouping" grouping is discussed in
Section 4.1.2.1 of [RFC9645].
- The "http-server-grouping" grouping is discussed in
Section 3.1.2.1 of [I-D.ietf-netconf-http-client-server].
- The "restconf-server-grouping" is discussed in Section 3.1.2.1
of this document.
3.1.2.4. The "restconf-server-app-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "restconf-
server-app-grouping" grouping:
grouping restconf-server-app-grouping:
+-- listen! {listen}?
| +-- endpoints
| +-- endpoint* [name]
| +-- name? string
| +---u restconf-server-listen-stack-grouping
+-- call-home! {callhome}?
+-- restconf-client* [name]
+-- name? string
+-- endpoints
| +-- endpoint* [name]
| +-- name? string
| +---u restconf-server-callhome-stack-grouping
+-- connection-type
| +-- (connection-type)
| +--:(persistent-connection)
| | +-- persistent!
| +--:(periodic-connection)
| +-- periodic!
| +-- period? uint16
| +-- anchor-time? yang:date-and-time
| +-- idle-timeout? uint16
+-- reconnect-strategy
+-- start-with? enumeration
+-- max-wait? uint16
+-- max-attempts? uint8
Comments:
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* The "restconf-server-app-grouping" defines the configuration for a
RESTCONF server that supports both listening for connections from
RESTCONF clients as well as initiating call-home connections to
RESTCONF clients.
* Both the "listen" and "call-home" subtrees must be enabled by
"feature" statements.
* For the referenced grouping statement(s):
- The "restconf-server-listen-stack-grouping" grouping is
discussed in Section 3.1.2.2 in this document.
- The "restconf-server-callhome-stack-grouping" grouping is
discussed in Section 3.1.2.3 in this document.
3.1.3. Protocol-accessible Nodes
The following tree diagram [RFC8340] lists all the protocol-
accessible nodes defined in the "ietf-restconf-server" module:
module: ietf-restconf-server
+--rw restconf-server {central-restconf-server-supported}?
+---u restconf-server-app-grouping
Comments:
* Protocol-accessible nodes are those nodes that are accessible when
the module is "implemented", as described in Section 5.6.5 of
[RFC7950].
* The top-level node "restconf-server" is additionally constrained
by the feature "central-restconf-server-supported".
* The "restconf-server-app-grouping" grouping is discussed in
Section 3.1.2.4 in this document.
* The reason for why "restconf-server-app-grouping" exists separate
from the protocol-accessible nodes definition is so as to enable
instances of restconf-server-app-grouping to be instantiated in
other locations, as may be needed or desired by some modules.
3.2. Example Usage
The following example illustrates configuring a RESTCONF server to
listen for RESTCONF client connections, as well as configuring call-
home to one RESTCONF client.
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This example is consistent with the examples presented in
Section 2.2.1 of [RFC9641] and Section 2.2.1 of [RFC9642].
=============== NOTE: '\' line wrapping per RFC 8792 ================
<restconf-server
xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-server"
xmlns:x509c2n="urn:ietf:params:xml:ns:yang:ietf-x509-cert-to-name">
<!-- endpoints to listen for RESTCONF connections on -->
<listen>
<endpoints>
<endpoint>
<name>http-over-tls</name>
<http-over-tls>
<tcp-server-parameters>
<local-bind>
<local-address>192.0.2.2</local-address>
</local-bind>
</tcp-server-parameters>
<tls-server-parameters>
<server-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</server-identity>
<client-authentication>
<ca-certs>
<central-truststore-reference>trusted-client-ca-cert\
s</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-client-ee-cert\
s</central-truststore-reference>
</ee-certs>
</client-authentication>
<keepalives>
<peer-allowed-to-send/>
</keepalives>
</tls-server-parameters>
<http-server-parameters>
<server-name>foo.example.com</server-name>
</http-server-parameters>
<restconf-server-parameters>
<client-identity-mappings>
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<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>scooby-doo</name>
</cert-to-name>
<cert-to-name>
<id>2</id>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
</client-identity-mappings>
</restconf-server-parameters>
</http-over-tls>
</endpoint>
<endpoint>
<name>http-over-quic</name>
<http-over-quic>
<udp-server-parameters>
<local-bind>
<local-address>192.0.2.2</local-address>
</local-bind>
</udp-server-parameters>
<tls-server-parameters>
<server-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</server-identity>
<client-authentication>
<ca-certs>
<central-truststore-reference>trusted-client-ca-cert\
s</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-client-ee-cert\
s</central-truststore-reference>
</ee-certs>
</client-authentication>
<keepalives>
<peer-allowed-to-send/>
</keepalives>
</tls-server-parameters>
<http-server-parameters>
<server-name>foo.example.com</server-name>
</http-server-parameters>
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<restconf-server-parameters>
<client-identity-mappings>
<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>scooby-doo</name>
</cert-to-name>
<cert-to-name>
<id>2</id>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
</client-identity-mappings>
</restconf-server-parameters>
</http-over-quic>
</endpoint>
</endpoints>
</listen>
<!-- call home to a RESTCONF client with two endpoints -->
<call-home>
<restconf-client>
<name>config-manager</name>
<endpoints>
<endpoint>
<name>east-data-center</name>
<http-over-tls>
<tcp-client-parameters>
<remote-address>east.example.com</remote-address>
<keepalives>
<idle-time>7200</idle-time>
<max-probes>9</max-probes>
<probe-interval>75</probe-interval>
</keepalives>
</tcp-client-parameters>
<tls-server-parameters>
<server-identity>
<certificate>
<central-keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-k\
ey>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</server-identity>
<client-authentication>
<ca-certs>
<central-truststore-reference>trusted-client-ca-ce\
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rts</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-client-ee-ce\
rts</central-truststore-reference>
</ee-certs>
</client-authentication>
<keepalives>
<test-peer-aliveness>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</tls-server-parameters>
<http-server-parameters>
<server-name>foo.example.com</server-name>
</http-server-parameters>
<restconf-server-parameters>
<client-identity-mappings>
<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>scooby-doo</name>
</cert-to-name>
<cert-to-name>
<id>2</id>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
</client-identity-mappings>
</restconf-server-parameters>
</http-over-tls>
</endpoint>
<endpoint>
<name>west-data-center</name>
<http-over-tls>
<tcp-client-parameters>
<remote-address>west.example.com</remote-address>
<keepalives>
<idle-time>7200</idle-time>
<max-probes>9</max-probes>
<probe-interval>75</probe-interval>
</keepalives>
</tcp-client-parameters>
<tls-server-parameters>
<server-identity>
<certificate>
<central-keystore-reference>
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<asymmetric-key>rsa-asymmetric-key</asymmetric-k\
ey>
<certificate>ex-rsa-cert</certificate>
</central-keystore-reference>
</certificate>
</server-identity>
<client-authentication>
<ca-certs>
<central-truststore-reference>trusted-client-ca-ce\
rts</central-truststore-reference>
</ca-certs>
<ee-certs>
<central-truststore-reference>trusted-client-ee-ce\
rts</central-truststore-reference>
</ee-certs>
</client-authentication>
<keepalives>
<test-peer-aliveness>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</test-peer-aliveness>
</keepalives>
</tls-server-parameters>
<http-server-parameters>
<server-name>foo.example.com</server-name>
</http-server-parameters>
<restconf-server-parameters>
<client-identity-mappings>
<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>scooby-doo</name>
</cert-to-name>
<cert-to-name>
<id>2</id>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
</client-identity-mappings>
</restconf-server-parameters>
</http-over-tls>
</endpoint>
</endpoints>
<connection-type>
<periodic>
<idle-timeout>300</idle-timeout>
<anchor-time>2023-03-15T01:30:00Z</anchor-time>
<period>60</period>
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</periodic>
</connection-type>
<reconnect-strategy>
<start-with>last-connected</start-with>
<max-wait>3</max-wait>
<max-attempts>3</max-attempts>
</reconnect-strategy>
</restconf-client>
</call-home>
</restconf-server>
3.3. YANG Module
This YANG module has normative references to [RFC6991], [RFC7407],
[RFC8040], [RFC8071], [RFC9643], [RFC9645], and
[I-D.ietf-netconf-http-client-server].
<CODE BEGINS> file "ietf-restconf-server@2025-04-24.yang"
module ietf-restconf-server {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-server";
prefix rcs;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-x509-cert-to-name {
prefix x509c2n;
reference
"RFC 7407: A YANG Data Model for SNMP Configuration";
}
import ietf-tcp-client {
prefix tcpc;
reference
"RFC DDDD: YANG Groupings for TCP Clients and TCP Servers";
}
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import ietf-tcp-server {
prefix tcps;
reference
"RFC DDDD: YANG Groupings for TCP Clients and TCP Servers";
}
import ietf-tls-server {
prefix tlss;
reference
"RFC FFFF: YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-http-server {
prefix https;
reference
"RFC GGGG: YANG Groupings for HTTP Clients and HTTP Servers";
}
import ietf-udp-server {
prefix udps;
reference
"RFC JJJJ: YANG Groupings for UDP Clients and UDP Servers";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: https://datatracker.ietf.org/wg/netconf
WG List: NETCONF WG list <mailto:netconf@ietf.org>
Author: Kent Watsen <mailto:kent+ietf@watsen.net>";
description
"This module contains a collection of YANG definitions
for configuring RESTCONF servers.
Copyright (c) 2025 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 IIII
(https://www.rfc-editor.org/info/rfcIIII); see the RFC
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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 2025-04-24 {
description
"Initial version";
reference
"RFC IIII: A YANG Data Model for RESTCONF Clients and Server";
}
// Features
feature listen {
description
"The 'listen' feature indicates that the RESTCONF server
supports listening for RESTCONF client connections.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature tcp-listen {
if-feature listen;
description
"The 'tcp-listen' feature indicates that the RESTCONF server
supports opening a port to listen for incoming RESTCONF over
TCP client connections. The TLS connections are expected to
be terminated by an external system.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature tls-listen {
if-feature listen;
description
"The 'tls-listen' feature indicates that the RESTCONF server
supports opening a port to listen for incoming RESTCONF over
TLS client connections, whereby the TLS connections are
terminated by the server itself.";
reference
"RFC 8040: RESTCONF Protocol";
}
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feature quic-listen {
if-feature listen;
description
"The 'quic-listen' feature indicates that the RESTCONF server
supports opening a port to listen for incoming RESTCONF over
QUIC client connections.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature callhome {
description
"The 'callhome' feature indicates that the RESTCONF server
supports initiating 'call home' connections to RESTCONF
clients.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
feature tls-callhome {
if-feature callhome;
description
"The 'tls-callhome' feature indicates that the RESTCONF server
supports initiating 'call home' connections to RESTCONF
clients using TLS per RFC 8071.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
feature central-restconf-server-supported {
description
"The 'central-restconf-server-supported' feature indicates
that the server supports the top-level 'restconf-server'
node.
This feature is needed as some servers may want to use
features defined in this module, which requires this
module to be implemented, without having to support
the top-level 'restconf-server' node.";
}
// Groupings
grouping restconf-server-grouping {
description
"A grouping for configuring a RESTCONF server
without any consideration for how underlying transport
sessions are established.
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Note that this grouping uses a fairly typical descendant
node name such that a stack of 'uses' statements will
have name conflicts. It is intended that the consuming
data model will resolve the issue by wrapping the 'uses'
statement in a container called, e.g.,
'restconf-server-parameters'. This model purposely does
not do this itself so as to provide maximum flexibility
to consuming models.";
container client-identity-mappings {
description
"Specifies mappings through which RESTCONF client X.509
certificates are used to determine a RESTCONF username.
If no matching and valid cert-to-name list entry can be
found, then the RESTCONF server MUST close the connection,
and MUST NOT accept RESTCONF messages over it.";
reference
"RFC 7407: A YANG Data Model for SNMP Configuration.";
uses x509c2n:cert-to-name {
refine "cert-to-name/fingerprint" {
mandatory false;
description
"A 'fingerprint' value does not need to be specified
when the 'cert-to-name' mapping is independent of
fingerprint matching. A 'cert-to-name' having no
fingerprint value will match any client certificate
and therefore SHOULD only be present at the end of
the user-ordered 'cert-to-name' list.";
}
}
}
}
grouping restconf-server-listen-stack-grouping {
description
"A grouping for configuring a RESTCONF server
'listen' protocol stack for listening on a single port.";
choice transport {
mandatory true;
description
"Selects between available transports.";
case http-over-tcp {
if-feature "tcp-listen";
container http-over-tcp {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled externally.";
container external-endpoint {
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presence
"Identifies that an external endpoint has been
configured. This statement is present so the
mandatory descendant nodes do not imply that
this node must be configured.";
description
"Provides information for the external endpoint.";
leaf address {
type inet:host;
mandatory true;
description
"The IP address or hostname of the external
endpoint clients connect to. This value may
be used in server-generated messages sent to
clients.";
}
leaf port {
type inet:port-number;
default "443";
description
"The port number on the external system clients
connect to. This value may be used in server
generated messages sent to clients. If no value
is specified, the IANA-assigned well-known port
value for 'https' (443) is assumed.";
}
leaf trusted-proxy-count {
type uint8 {
range "1..max"; // non-zero
}
default 1;
description
"The number of proxies in front of the RESTCONF
server, including the external endpoint. This
value may be used to assist parsing proxy-sensitive
HTTP header fields. If no value is specified, the
value '1' is assumed.";
}
leaf client-cert-var {
type string;
description
"The HTTP header variable used by the external
TLS-terminator to relay client certificates to this
RESTCONF server (e.g., 'X-Client-Cert'). This field
is not mandatory as RESTCONF client authentication
does not require client certificates.";
}
}
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container tcp-server-parameters {
description
"TCP-level server parameters.";
uses tcps:tcp-server-grouping {
refine "local-bind/local-port" {
default "80";
description
"The RESTCONF server will listen on the IANA-
assigned well-known port value for 'http'
(80) if no value is specified.";
}
}
}
container http-server-parameters {
description
"HTTP-level server parameters.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
"RESTCONF-level server parameters.";
uses rcs:restconf-server-grouping;
}
}
}
case http-over-tls {
if-feature "tls-listen";
container http-over-tls {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled internally (i.e.,
not by a TLS-terminator in front of the RESTCONF
server).";
container tcp-server-parameters {
description
"TCP-level server parameters.";
uses tcps:tcp-server-grouping {
refine "local-bind/local-port" {
default "443";
description
"The RESTCONF server will listen on the IANA-
assigned well-known port value for 'https'
(443) if no value is specified.";
}
}
}
container tls-server-parameters {
description
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"TLS-level server parameters.";
uses tlss:tls-server-grouping;
}
container http-server-parameters {
description
"HTTP-level server parameters.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
"RESTCONF-level server parameters.";
uses rcs:restconf-server-grouping;
}
}
}
case http-over-quic {
if-feature "quic-listen";
container http-over-quic {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled internally (i.e.,
not by a TLS-terminator in front of the RESTCONF
server).";
container udp-server-parameters {
description
"UDP-level server parameters.";
uses udps:udp-server {
refine "local-bind/local-port" {
default "443";
description
"The RESTCONF server will listen on the IANA-
assigned well-known port value for 'https'
(443) if no value is specified.";
}
}
}
container tls-server-parameters {
description
"TLS-level server parameters.";
uses tlss:tls-server-grouping;
}
container http-server-parameters {
description
"HTTP-level server parameters.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
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"RESTCONF-level server parameters.";
uses rcs:restconf-server-grouping;
}
}
}
}
}
grouping restconf-server-callhome-stack-grouping {
description
"A grouping for configuring a RESTCONF server call home
protocol stack, for a single outbound connection.";
choice transport {
mandatory true;
description
"Selects between available transports.";
case http-over-tls {
if-feature tls-callhome;
container http-over-tls {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled internally.";
container tcp-client-parameters {
description
"TCP-level client parameters.";
uses tcpc:tcp-client-grouping {
refine "remote-port" {
default "4336";
description
"The RESTCONF server will attempt to
connect to the IANA-assigned well-known
port for 'restconf-ch-tls' (4336) if no
value is specified.";
}
}
}
container tls-server-parameters {
description
"TLS-level server parameters.";
uses tlss:tls-server-grouping;
}
container http-server-parameters {
description
"HTTP-level server parameters.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
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"RESTCONF-level server parameters.";
uses rcs:restconf-server-grouping;
}
}
}
}
}
grouping restconf-server-app-grouping {
description
"A grouping for configuring a RESTCONF server
application that supports both 'listen' and call home
protocol stacks for a multiplicity of connections.";
container listen {
if-feature listen;
presence
"Identifies that the server has been configured to
listen for incoming client connections. This statement
is present so the mandatory descendant nodes do not
imply that this node must be configured.";
description
"Configures the RESTCONF server to listen for RESTCONF
client connections.";
container endpoints {
description
"Container for a list of endpoints.";
list endpoint {
key "name";
min-elements 1;
description
"List of endpoints to listen for RESTCONF connections.";
leaf name {
type string;
description
"An arbitrary name for the RESTCONF listen endpoint.";
}
uses restconf-server-listen-stack-grouping;
}
}
} // listen
container call-home {
if-feature callhome;
presence
"Identifies that the server has been configured to initiate
call home connections. This statement is present so the
mandatory descendant nodes do not imply that this node
must be configured.";
description
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"Configures the RESTCONF server to initiate the underlying
transport connection to RESTCONF clients.";
list restconf-client {
key "name";
min-elements 1;
description
"List of RESTCONF clients the RESTCONF server is to
maintain simultaneous call home connections with.";
leaf name {
type string;
description
"An arbitrary name for the remote RESTCONF client.";
}
container endpoints {
description
"Container for the list of endpoints.";
list endpoint {
key "name";
min-elements 1;
ordered-by user;
description
"User-ordered list of endpoints for this RESTCONF
client. Defining more than one enables high-
availability.";
leaf name {
type string;
description
"An arbitrary name for this endpoint.";
}
uses restconf-server-callhome-stack-grouping;
}
}
container connection-type {
description
"Indicates the RESTCONF server's preference for how the
RESTCONF connection is maintained.";
choice connection-type {
mandatory true;
description
"Selects between available connection types.";
case persistent-connection {
container persistent {
presence
"Indicates that a persistent connection is to be
maintained.";
description
"Maintain a persistent connection to the RESTCONF
client. If the connection goes down, immediately
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start trying to reconnect to the RESTCONF client,
using the reconnection strategy.
This connection type minimizes any RESTCONF
client to RESTCONF server data-transfer delay,
albeit at the expense of holding resources
longer.";
}
}
case periodic-connection {
container periodic {
presence
"Indicates that a periodic connection is to be
maintained.";
description
"Periodically connect to the RESTCONF client.
This connection type decreases resource
utilization, albeit with increased delay in
RESTCONF client to RESTCONF server interactions.
The RESTCONF client SHOULD gracefully close
the underlying TLS connection upon completing
planned activities. If the underlying TLS
connection is not closed gracefully, the
RESTCONF server MUST immediately attempt
to reestablish the connection.
Connections are established at the same start
time regardless how long the previous connection
stayed open.
In the case that the previous connection is
still active (i.e., the RESTCONF client has not
closed it yet), establishing a new connection
is NOT RECOMMENDED.";
leaf period {
type uint16;
units "minutes";
default "60";
description
"Duration of time between periodic connections.";
}
leaf anchor-time {
type yang:date-and-time {
// constrained to minute-level granularity
pattern '[0-9]{4}-(1[0-2]|0[1-9])-(0[1-9]|[1-2]'
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+ '[0-9]|3[0-1])T(0[0-9]|1[0-9]|2[0-3]):['
+ '0-5][0-9]:00(Z|[\+\-]((1[0-3]|0[0-9]):'
+ '([0-5][0-9])|14:00))?';
}
description
"Designates a timestamp before or after which a
series of periodic connections are determined.
The periodic connections occur at a whole
multiple interval from the anchor time.
If an 'anchor-time' is not provided, then the
server MAY implicitly set it to the time when
this configuraton is applied (e.g., on boot).
For example, for an anchor time is 15 minutes
past midnight and a period interval of 24 hours,
then a periodic connection will occur 15 minutes
past midnight everyday.";
}
leaf idle-timeout {
type uint16;
units "seconds";
default "180";
description
"Specifies the maximum number of seconds that
the underlying TCP session may remain idle.
A TCP session will be dropped if it is idle
for an interval longer than this number of
seconds. If set to zero, then the server
will never drop a session because it is idle.";
}
}
}
}
}
container reconnect-strategy {
description
"The reconnection strategy directs how a RESTCONF server
reconnects to a RESTCONF client after discovering its
connection to the client has dropped, even if due to a
reboot. The RESTCONF server starts with the specified
endpoint and tries to connect to it max-attempts times
before trying the next endpoint in the list (round
robin).";
leaf start-with {
type enumeration {
enum first-listed {
description
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"Indicates that reconnections should start with
the first endpoint listed.";
}
enum last-connected {
description
"Indicates that reconnections should start with
the endpoint last connected to, if known. If
no previous connection is known, then the
first endpoint configured is used.";
}
enum random-selection {
description
"Indicates that reconnections should start with
a random endpoint.";
}
}
default "first-listed";
description
"Specifies which of the RESTCONF client's endpoints
the RESTCONF server should start with when trying
to connect to the RESTCONF client.";
}
leaf max-wait {
type uint16 {
range "1..max";
}
units "seconds";
default "5";
description
"Specifies the amount of time in seconds after which,
if the connection is not established, an endpoint
connection attempt is considered unsuccessful.";
}
leaf max-attempts {
type uint8 {
range "1..max";
}
default "3";
description
"Specifies the number times the RESTCONF server tries
to connect to a specific endpoint before moving on to
the next endpoint in the list (round robin).";
}
}
}
} // call-home
} // restconf-server-app-grouping
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// Protocol accessible node for servers that implement this module.
container restconf-server {
if-feature central-restconf-server-supported;
uses restconf-server-app-grouping;
description
"Top-level container for RESTCONF server configuration.";
}
}
<CODE ENDS>
4. Security Considerations
4.1. Considerations for the "ietf-restconf-client" YANG Module
This section is modeled after the template defined in Section 3.7.1
of [RFC8407].
The "ietf-restconf-client" YANG module defines data nodes that are
designed to be accessed via YANG-based management protocols, such as
NETCONF [RFC6241] and RESTCONF [RFC8040]. The YANG-based management
protocols have to use a secure transport layer such as SSH [RFC4252],
TLS [RFC8446], or QUIC [RFC9000]. The YANG-based management
protocols also have to use mutual authentication.
The Network Access Control Model (NACM) [RFC8341] provides the means
to restrict access for particular users to a pre-configured subset of
all available protocol operations and content.
This YANG module uses groupings from other YANG modules that define
nodes that may be considered sensitive or vulnerable in network
environments. Please review the Security Considerations for
dependent YANG modules for information as to which nodes may be
considered sensitive or vulnerable in network environments.
This YANG module uses groupings defined in other RFCs that define
data nodes that do set the NACM "default-deny-all" and "default-deny-
write" extensions.
None of the readable data nodes in this YANG module are considered
sensitive or vulnerable in network environments. The NACM "default-
deny-all" extension has not been set for any data nodes defined in
this module.
None of the writable data nodes in this YANG module are considered
sensitive or vulnerable in network environments. The NACM "default-
deny-write" extension has not been set for any data nodes defined in
this module.
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This YANG module does not define any RPCs, actions, or notifications,
and thus the security consideration for such is not provided here.
This YANG module enables the possibility for a RESTCONF client to
open a port to listen for non-TLS-based RESTCONF Call Home
connections [RFC8071]. Whilst RESTCONF [RFC8040] requires HTTPS,
this configuration is provided for deployments having a TLS-
terminator (e.g., a load balancer) in front of the TLS client. In
such a case, the security boundary extends to the TLS-terminator.
4.2. Considerations for the "ietf-restconf-server" YANG Module
This section is modeled after the template defined in Section 3.7.1
of [RFC8407].
The "ietf-restconf-server" YANG module defines data nodes that are
designed to be accessed via YANG-based management protocols, such as
NETCONF [RFC6241] and RESTCONF [RFC8040]. The YANG-based management
protocols have to use a secure transport layer such as SSH [RFC4252],
TLS [RFC8446], or QUIC [RFC9000]. The YANG-based management
protocols also have to use mutual authentication.
The Network Access Control Model (NACM) [RFC8341] provides the means
to restrict access for particular users to a pre-configured subset of
all available protocol operations and content.
This YANG module uses groupings from other YANG modules that define
nodes that may be considered sensitive or vulnerable in network
environments. Please review the Security Considerations for
dependent YANG modules for information as to which nodes may be
considered sensitive or vulnerable in network environments.
This YANG module uses groupings defined in other RFCs that define
data nodes that do set the NACM "default-deny-all" and "default-deny-
write" extensions.
None of the readable data nodes in this YANG module are considered
sensitive or vulnerable in network environments. The NACM "default-
deny-all" extension has not been set for any data nodes defined in
this module.
None of the writable data nodes in this YANG module are considered
sensitive or vulnerable in network environments. The NACM "default-
deny-write" extension has not been set for any data nodes defined in
this module.
This YANG module does not define any RPCs, actions, or notifications,
and thus the security consideration for such is not provided here.
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This YANG module enables the possibility for a RESTCONF server to
open a port to listen for non-TLS-based RESTCONF connections. Whilst
RESTCONF [RFC8040] requires HTTPS, this configuration is provided to
support deploying a TLS-terminator (e.g., a load balancer) in front
of the TLS server. In such a case, the security boundary extends to
the TLS-terminator.
5. IANA Considerations
5.1. The "IETF XML" Registry
This document registers two URIs in the "ns" subregistry of the IETF
XML Registry [RFC3688]. Following the format in [RFC3688], the
following registrations are requested:
URI: urn:ietf:params:xml:ns:yang:ietf-restconf-client
Registrant Contact: The IESG
XML: N/A, the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-restconf-server
Registrant Contact: The IESG
XML: N/A, the requested URI is an XML namespace.
5.2. The "YANG Module Names" Registry
This document registers two YANG modules in the YANG Module Names
registry [RFC6020]. Following the format in [RFC6020], the following
registrations are requested:
Name: ietf-restconf-client
Namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-client
Prefix: rcc
Reference: RFC IIII
Maintained by IANA: N
Name: ietf-restconf-server
Namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-server
Prefix: rcs
Reference: RFC IIII
Maintained by IANA: N
6. References
6.1. Normative References
[I-D.ietf-netconf-http-client-server]
Watsen, K., "YANG Groupings for HTTP Clients and HTTP
Servers", Work in Progress, Internet-Draft, draft-ietf-
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netconf-http-client-server-25, 12 February 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
http-client-server-25>.
[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>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7407] Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for
SNMP Configuration", RFC 7407, DOI 10.17487/RFC7407,
December 2014, <https://www.rfc-editor.org/info/rfc7407>.
[RFC7950] Bjorklund, M., Ed., "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., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8071] Watsen, K., "NETCONF Call Home and RESTCONF Call Home",
RFC 8071, DOI 10.17487/RFC8071, February 2017,
<https://www.rfc-editor.org/info/rfc8071>.
[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>.
[RFC9642] Watsen, K., "A YANG Data Model for a Keystore", RFC 9642,
DOI 10.17487/RFC9642, October 2024,
<https://www.rfc-editor.org/info/rfc9642>.
[RFC9643] Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients
and TCP Servers", RFC 9643, DOI 10.17487/RFC9643, October
2024, <https://www.rfc-editor.org/info/rfc9643>.
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[RFC9645] Watsen, K., "YANG Groupings for TLS Clients and TLS
Servers", RFC 9645, DOI 10.17487/RFC9645, October 2024,
<https://www.rfc-editor.org/info/rfc9645>.
6.2. Informative References
[I-D.ietf-netconf-netconf-client-server]
Watsen, K., "NETCONF Client and Server Models", Work in
Progress, Internet-Draft, draft-ietf-netconf-netconf-
client-server-38, 12 February 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
netconf-client-server-38>.
[I-D.ietf-netconf-restconf-client-server]
Watsen, K., "RESTCONF Client and Server Models", Work in
Progress, Internet-Draft, draft-ietf-netconf-restconf-
client-server-42, 14 April 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
restconf-client-server-42>.
[I-D.ietf-netmod-system-config]
Ma, Q., Wu, Q., and C. Feng, "System-defined
Configuration", Work in Progress, Internet-Draft, draft-
ietf-netmod-system-config-12, 12 February 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
system-config-12>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
January 2006, <https://www.rfc-editor.org/info/rfc4252>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
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[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8407] Bierman, A., "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>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
[RFC9640] Watsen, K., "YANG Data Types and Groupings for
Cryptography", RFC 9640, DOI 10.17487/RFC9640, October
2024, <https://www.rfc-editor.org/info/rfc9640>.
[RFC9641] Watsen, K., "A YANG Data Model for a Truststore",
RFC 9641, DOI 10.17487/RFC9641, October 2024,
<https://www.rfc-editor.org/info/rfc9641>.
[RFC9644] Watsen, K., "YANG Groupings for SSH Clients and SSH
Servers", RFC 9644, DOI 10.17487/RFC9644, October 2024,
<https://www.rfc-editor.org/info/rfc9644>.
Appendix A. Change Log
A.1. 00 to 01
* Renamed "keychain" to "keystore".
A.2. 01 to 02
* Filled in previously missing 'ietf-restconf-client' module.
* Updated the ietf-restconf-server module to accommodate new
grouping 'ietf-tls-server-grouping'.
A.3. 02 to 03
* Refined use of tls-client-grouping to add a must statement
indicating that the TLS client must specify a client-certificate.
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* Changed restconf-client??? to be a grouping (not a container).
A.4. 03 to 04
* Added RFC 8174 to Requirements Language Section.
* Replaced refine statement in ietf-restconf-client to add a
mandatory true.
* Added refine statement in ietf-restconf-server to add a must
statement.
* Now there are containers and groupings, for both the client and
server models.
* Now tree diagrams reference ietf-netmod-yang-tree-diagrams
* Updated examples to inline key and certificates (no longer a
leafref to keystore)
A.5. 04 to 05
* Now tree diagrams reference ietf-netmod-yang-tree-diagrams
* Updated examples to inline key and certificates (no longer a
leafref to keystore)
A.6. 05 to 06
* Fixed change log missing section issue.
* Updated examples to match latest updates to the crypto-types,
trust-anchors, and keystore drafts.
* Reduced line length of the YANG modules to fit within 69 columns.
A.7. 06 to 07
* removed "idle-timeout" from "persistent" connection config.
* Added "random-selection" for reconnection-strategy's "starts-with"
enum.
* Replaced "connection-type" choice default (persistent) with
"mandatory true".
* Reduced the periodic-connection's "idle-timeout" from 5 to 2
minutes.
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* Replaced reconnect-timeout with period/anchor-time combo.
A.8. 07 to 08
* Modified examples to be compatible with new crypto-types algs
A.9. 08 to 09
* Corrected use of "mandatory true" for "address" leafs.
* Updated examples to reflect update to groupings defined in the
keystore draft.
* Updated to use groupings defined in new TCP and HTTP drafts.
* Updated copyright date, boilerplate template, affiliation, and
folding algorithm.
A.10. 09 to 10
* Reformatted YANG modules.
A.11. 10 to 11
* Adjusted for the top-level "demux container" added to groupings
imported from other modules.
* Added "must" expressions to ensure that keepalives are not
configured for "periodic" connections.
* Updated the boilerplate text in module-level "description"
statement to match copyeditor convention.
* Moved "expanded" tree diagrams to the Appendix.
A.12. 11 to 12
* Removed the 'must' statement limiting keepalives in periodic
connections.
* Updated models and examples to reflect removal of the "demux"
containers in the imported models.
* Updated the "periodic-connnection" description statements to
better describe behavior when connections are not closed
gracefully.
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* Updated text to better reference where certain examples come from
(e.g., which Section in which draft).
* In the server model, commented out the "must 'pinned-ca-certs or
pinned-client-certs'" statement to reflect change made in the TLS
draft whereby the trust anchors MAY be defined externally.
* Replaced the 'listen', 'initiate', and 'call-home' features with
boolean expressions.
A.13. 12 to 13
* Updated to reflect changes in trust-anchors drafts (e.g., s/trust-
anchors/truststore/g + s/pinned.//)
* In ietf-restconf-server, Added 'http-listen' (not https-listen)
choice, to support case when server is behind a TLS-terminator.
* Refactored server module to be more like other 'server' models.
If folks like it, will also apply to the client model, as well as
to both the netconf client/server models. Now the 'restconf-
server-grouping' is just the RC-specific bits (i.e., the "demux"
container minus the container), 'restconf-server-
[listen|callhome]-stack-grouping' is the protocol stack for a
single connection, and 'restconf-server-app-grouping' is
effectively what was before (both listen+callhome for many
inbound/outbound endpoints).
A.14. 13 to 14
* Updated examples to reflect ietf-crypto-types change (e.g.,
identities --> enumerations)
* Adjusting from change in TLS client model (removing the top-level
'certificate' container).
* Added "external-endpoint" to the "http-listen" choice in ietf-
restconf-server.
A.15. 14 to 15
* Added missing "or https-listen" clause in a "must" expression.
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* Refactored the client module similar to how the server module was
refactored in -13. Now the 'restconf-client-grouping' is just the
RC-specific bits, the 'restconf-client-[initiate|listen]-stack-
grouping' is the protocol stack for a single connection, and
'restconf-client-app-grouping' is effectively what was before
(both listen+callhome for many inbound/outbound endpoints).
A.16. 15 to 16
* Added refinement to make "cert-to-name/fingerprint" be mandatory
false.
* Commented out refinement to "tls-server-grouping/client-
authentication" until a better "must" expression is defined.
* Updated restconf-client example to reflect that http-client-
grouping no longer has a "protocol-version" leaf.
A.17. 16 to 17
* Updated examples to include the "*-key-format" nodes.
* Updated examples to remove the "required" nodes.
A.18. 17 to 18
* Updated examples to reflect new "bag" addition to truststore.
A.19. 18 to 19
* Updated examples to remove the 'algorithm' nodes.
* Updated examples to reflect the new TLS keepalives structure.
* Removed the 'protocol-versions' node from the restconf-server
examples.
* Added a "Note to Reviewers" note to first page.
A.20. 19 to 20
* Moved and changed "must" statement so that either TLS *or* HTTP
auth must be configured.
* Expanded "Data Model Overview section(s) [remove "wall" of tree
diagrams].
* Updated the Security Considerations section.
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A.21. 20 to 21
* Cleaned up titles in the IANA Consideratons section
* Fixed issues found by the SecDir review of the "keystore" draft.
A.22. 21 to 22
* Addressed comments raised by YANG Doctor in the ct/ts/ks drafts.
A.23. 22 to 23
* Further clarified why some 'presence' statements are present.
* Addressed nits found in YANG Doctor reviews.
* Aligned modules with `pyang -f` formatting.
A.24. 23 to 24
* Removed Appendix A with fully-expanded tree diagrams.
* Replaced "base64encodedvalue==" with "BASE64VALUE=" in examples.
* Minor editorial nits
A.25. 24 to 25
* Fixed up the 'WG Web' and 'WG List' lines in YANG module(s)
* Fixed up copyright (i.e., s/Simplified/Revised/) in YANG module(s)
A.26. 25 to 26
* Added feature "central-restconf-client-supported" to top-level
node "restconf-client".
* Added feature "central-restconf-server-supported" to top-level
node "restconf-server".
A.27. 26 to 27
* Updated per Shepherd reviews impacting the suite of drafts.
* Added "max-wait" leaf to the "reconnect-strategy" nodes.
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A.28. 27 to 28
* Updated per Shepherd reviews impacting the suite of drafts.
A.29. 28 to 29
* Updated (implicitly) via Tom Petch reviews.
* Fixed pattern statement for "leaf anchor-time".
* Updated examples to use IETF-sanctioned values.
A.30. 29 to 30
* Addresses AD review comments.
* Added note to Editor to fix line foldings.
* Removed "Conventions" section as there are no "BASE64VALUE="
values used in draft.
* Removed restconf-client-grouping, since it was empty.
* Removed erronious statement "client-identity-mappings" must be
enabled by a "feature".
* Added Security Considerations text to also look a SC-section from
imported modules.
* Removed "A wrapper around the foobar parameters to avoid name
collisions" text.
* Added container "endpoints" to wrap list "endpoint".
* Fixed if-feature "https-listen" to if-feature "https-call-home".
A.31. 30 to 31
* Addresses AD review by Rob Wilton.
A.32. 31 to 32
* Addresses 1st-round of IESG reviews.
A.33. 32 to 34
* Addresses issues found in OpsDir review of the ssh-client-server
draft.
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* s/defines/presents/ in a few places.
* Add refs to where the 'operational' and 'system' datastores are
defined.
* Renamed Security Considerations section s/Template for/
Considerations for/
A.34. 34 to 36
* Nothing changed. Only bumped for automation...
A.35. 38 to 39
* Aligned with updates to 'http-client-server' per IESG review.
* Renamed some 'feature' statements to be more like http-client-
server
A.36. 39 to 40
* Updated 2nd paragraph in Security Considerations section to match
RFC Editor's version for other drafts in the suite of client-
server drafts.
* Added a logically-impossible 'if-feature' statement to the 'uri'
components from the 'http-client-grouping', from the 'ietf-http-
client' YANG module.
A.37. 40 to 41
* In both the client and server YANG modules, added "if-feature"
statements to dependant features. This oversight was identified
by a WG member.
* In the server YANG module, added "leaf client-cert-var" to the
"external-endpoint" container to enable the HTTP header variable
used by an external TLS terminator to be configured. The need for
this was identified by an ISP deploying a RESTCONF server behind
an AWS ALB (application load balancer) that hardcodes an Amazon-
specific variable name.
A.38. 41 to 42
* Updated Security Considerations section per Mike Bishop's review.
Now more prominently calls out how HTTP (w/o TLS) may be
configured, despite being required by RESTCONF [RFC 8040], to
support external TLS-terminators (e.g., load balancers).
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A.39. 42 to 43
* Updated to reflect some of Med's AD-review comments.
* Fixed Security Considerations section update made in -42.
* Added 'trusted-proxy-count' to the "external-endpoint" node.
Acknowledgements
The authors would like to thank the following for lively discussions
on list and in the halls (ordered by first name): Alan Luchuk, Andy
Bierman, Balázs Kovács, Benoit Claise, Bert Wijnen David Lamparter,
Jürgen Schönwälder, Ladislav Lhotka, Martin Björklund, Med
Boucladair, Qiufang Ma, Mehmet Ersue, Michal Vaško, Mike Bishop, Phil
Shafer, Qiufang Ma, Radek Krejci, Ramkumar Dhanapal, Rob Wilton, Sean
Turner, and Tom Petch.
Author's Address
Kent Watsen
Watsen Networks
Email: kent+ietf@watsen.net
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