System-defined Configuration
draft-ietf-netmod-system-config-01
The information below is for an old version of the document.
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Authors | Qiufang Ma , Qin Wu , Chong Feng | ||
Last updated | 2023-01-04 | ||
Replaces | draft-ma-netmod-with-system | ||
RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-netmod-system-config-01
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 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 8 July 2023. Copyright Notice Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved. Ma, et al. Expires 8 July 2023 [Page 1] Internet-Draft System-defined Configuration January 2023 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 . . . . . . . . . . . . . . . . . . . . . . . . 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 Ma, et al. Expires 8 July 2023 [Page 2] Internet-Draft System-defined Configuration January 2023 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. Ma, et al. Expires 8 July 2023 [Page 3] Internet-Draft System-defined Configuration January 2023 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 Ma, et al. Expires 8 July 2023 [Page 4] Internet-Draft System-defined Configuration January 2023 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 Ma, et al. Expires 8 July 2023 [Page 5] Internet-Draft System-defined Configuration January 2023 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? Ma, et al. Expires 8 July 2023 [Page 6] Internet-Draft System-defined Configuration January 2023 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. Ma, et al. Expires 8 July 2023 [Page 7] Internet-Draft System-defined Configuration January 2023 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]. Ma, et al. Expires 8 July 2023 [Page 8] Internet-Draft System-defined Configuration January 2023 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. Ma, et al. Expires 8 July 2023 [Page 9] Internet-Draft System-defined Configuration January 2023 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. Ma, et al. Expires 8 July 2023 [Page 10] Internet-Draft System-defined Configuration January 2023 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 Ma, et al. Expires 8 July 2023 [Page 11] Internet-Draft System-defined Configuration January 2023 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? Ma, et al. Expires 8 July 2023 [Page 12] Internet-Draft System-defined Configuration January 2023 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; } } } } Ma, et al. Expires 8 July 2023 [Page 13] Internet-Draft System-defined Configuration January 2023 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. Ma, et al. Expires 8 July 2023 [Page 14] Internet-Draft System-defined Configuration January 2023 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; } } } } } Ma, et al. Expires 8 July 2023 [Page 15] Internet-Draft System-defined Configuration January 2023 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: Ma, et al. Expires 8 July 2023 [Page 16] Internet-Draft System-defined Configuration January 2023 <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> Ma, et al. Expires 8 July 2023 [Page 17] Internet-Draft System-defined Configuration January 2023 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: Ma, et al. Expires 8 July 2023 [Page 18] Internet-Draft System-defined Configuration January 2023 <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: Ma, et al. Expires 8 July 2023 [Page 19] Internet-Draft System-defined Configuration January 2023 <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> Ma, et al. Expires 8 July 2023 [Page 20] Internet-Draft System-defined Configuration January 2023 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: Ma, et al. Expires 8 July 2023 [Page 21] Internet-Draft System-defined Configuration January 2023 <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: Ma, et al. Expires 8 July 2023 [Page 22] Internet-Draft System-defined Configuration January 2023 <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: Ma, et al. Expires 8 July 2023 [Page 23] Internet-Draft System-defined Configuration January 2023 <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 Ma, et al. Expires 8 July 2023 [Page 24] Internet-Draft System-defined Configuration January 2023 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" } } } Ma, et al. Expires 8 July 2023 [Page 25] Internet-Draft System-defined Configuration January 2023 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> Ma, et al. Expires 8 July 2023 [Page 26] Internet-Draft System-defined Configuration January 2023 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. Ma, et al. Expires 8 July 2023 [Page 27] Internet-Draft System-defined Configuration January 2023 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 Ma, et al. Expires 8 July 2023 [Page 28] Internet-Draft System-defined Configuration January 2023 | | +---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: Ma, et al. Expires 8 July 2023 [Page 29] Internet-Draft System-defined Configuration January 2023 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: Ma, et al. Expires 8 July 2023 [Page 30] Internet-Draft System-defined Configuration January 2023 <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>: Ma, et al. Expires 8 July 2023 [Page 31] Internet-Draft System-defined Configuration January 2023 <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"; Ma, et al. Expires 8 July 2023 [Page 32] Internet-Draft System-defined Configuration January 2023 } 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"; } Ma, et al. Expires 8 July 2023 [Page 33] Internet-Draft System-defined Configuration January 2023 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]. Ma, et al. Expires 8 July 2023 [Page 34] Internet-Draft System-defined Configuration January 2023 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]. Ma, et al. Expires 8 July 2023 [Page 35] Internet-Draft System-defined Configuration January 2023 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 Ma, et al. Expires 8 July 2023 [Page 36] Internet-Draft System-defined Configuration January 2023 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>. Ma, et al. Expires 8 July 2023 [Page 37] Internet-Draft System-defined Configuration January 2023 [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>. Ma, et al. Expires 8 July 2023 [Page 38] Internet-Draft System-defined Configuration January 2023 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> Ma, et al. Expires 8 July 2023 [Page 39] Internet-Draft System-defined Configuration January 2023 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> Ma, et al. Expires 8 July 2023 [Page 40] Internet-Draft System-defined Configuration January 2023 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>: Ma, et al. Expires 8 July 2023 [Page 41] Internet-Draft System-defined Configuration January 2023 <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 Ma, et al. Expires 8 July 2023 [Page 42] Internet-Draft System-defined Configuration January 2023 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 Ma, et al. Expires 8 July 2023 [Page 43]