RESTCONF Update to Support the NMDA
draft-ietf-netconf-nmda-restconf-01

Abstract

This document updates RESTCONF [RFC8040] in order to support the Network Management Datastore Architecture (NMDA) defined in [I-D.ietf-netmod-revised-datastores].

Status of This Memo

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Copyright Notice

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Table of Contents

• 1. Introduction
• 1.1. Terminology
• 2. Summary of Updates to RFC 8040
• 3. Conformance
• 4. The {+restconf}/ds/<datastore> Resources
• 5. Protocol Operations
• 5.1. The "with‑origin" query parameter
• 6. Security Considerations
• 7. IANA Considerations
• 8. Normative References
• Appendix A. Example
• Authors' Addresses

1. Introduction

This document updates RESTCONF [RFC8040] in order to support the Network Management Datastore Architecture (NMDA) defined in [I-D.ietf-netmod-revised-datastores].

The solution presented in this document is backwards compatible with [RFC8040]. This is achieved by it only adding new top-level resources, and thereby leaving the semantics of all existing resources alone.

1.1. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

The following terms are defined in [I-D.ietf-netmod-revised-datastores] and are not redefined here:

• operational state datastore
• running configuration datastore
• intended configuration datastore

2. Summary of Updates to RFC 8040

This document updates [RFC8040] in the following ways:

• Adds new top-level resource "/ds".
• Adds new query parameter "with‑origin".
• Section 3.5.4, Paragraph 3 in [RFC8040] doesn't apply when interacting with any resource under {+restconf}/ds.
• Updates section 10 in [RFC8040] by requiring servers that support NMDA to implement "ietf‑yang‑library" as defined in [I-D.nmdsdt-netconf-rfc7895bis].

3. Conformance

RFC Ed.: Update 201X-XX-XX below with correct date.

An NMDA-compliant RESTCONF server MUST support the operational state datastore. Such a server identifies that it supports NMDA both by implementing the {+restconf}/ds/ietf-datastores:operational resource, and by implementing at least revision 201X-XX-XX of the "ietf‑yang‑library" module, as specified in [I-D.nmdsdt-netconf-rfc7895bis].

A RESTCONF client can test if a server supports the NMDA by using either the HEAD or GET methods on {+restconf}/ds/ietf-datastores:operational.

4. The {+restconf}/ds/<datastore> Resources

This document defines a set of new resources representing datastores as defined in [I-D.ietf-netmod-revised-datastores]. These resources are available using the resource path template:

  {+restconf}/ds/<datastore>
	    

Where <datastore> is encoded as an "identity" according to the JSON encoding rules for identities, defined in Section 4 of [RFC7951]. Such an identity MUST be derived from the "datastore" identity in "ietf‑datastores" [I-D.ietf-netmod-revised-datastores].

Specifically:

• The resource {+restconf}/ds/ietf-datastores:operational refers to the operational state datastore.
• The resource {+restconf}/ds/ietf-datastores:running refers to the running configuration datastore.
• The resource {+restconf}/ds/ietf-datastores:intended refers to the intended configuration datastore.

An NMDA-compliant server MUST implement {+restconf}/ds/ietf-datastores:operational. Other datastore resources are optional to implement.

If a server implements the example datastore "ds‑ephemeral" in the module "example‑ds‑ephemeral", it would implement the resource {+restconf}/ds/example-ds-ephemeral:ds-ephemeral.

5. Protocol Operations

All existing protocol operations defined in [RFC8040] for the {+restconf}/data resource are available for all of the new datastore resources with the following exceptions:

• Dynamic datastores are excluded, as each dynamic datastore definition needs to be reviewed for what protocol operations it supports.
• Some datastores are read-only by nature (e.g., <intended>), and hence any attempt to modify these datastores will fail.
• The "with‑defaults" query parameter ([RFC8040], Section 4.8.9) does not apply when interacting with {+restconf}/ds/ietf-datastores:operational. This means that all values are always returned from the operational state datastore, even if a node happens to have a default statement in the YANG module, and this default value is being used by the server. If the "with‑defaults" query parameter is present in a request to this resource, the server MUST return a response with a "400 Bad Request" status-line. The error-tag value "invalid‑value" is used in this case.
• [RFC8040], section 3.5.4, paragraph 3 does not apply when interacting with any resource under {+restconf}/ds.

5.1. The "with‑origin" query parameter

The GET operation adds a new query parameter named "with‑origin", which if present, requests that the server includes "origin" metadata anotations in its response, as detailed in the NMDA. This parameter is only valid when querying {+restconf}/ds/ietf-datastores:operational or any datastores with identities derived from the "operational" identity. Otherwise, if an invalid datastore is specified then the server MUST return a response witha a "400 Bad Request" status-line, using an error-tag value of "invalid‑value". "origin" metadata annotations are not included unless a client explicitly requests them.

Data from <operational> can come from multiple sources. The server should return the most accurate value for the "origin" metadata annotation as possible, indicating the source of the operational value, as specified in section 5.3.4 of the NMDA.

When encoding the origin metadata annotation for a hierarchy of returned nodes, the annotation may be omitted for a child node when the value matches that of the parent node (as described in ietf-origin@2017-08-17). [RFC Editor, please check published revision date.]

The "with‑origin" query parameter is optional to support. It is identified with the URI:

  urn:ietf:params:restconf:capability:with-origin:1.0
	    

6. Security Considerations

TBD

7. IANA Considerations

This document defines one capability in the "RESTCONF Capability URNs" registry defined in [RFC8040]:

  Index          Capability Identifier
  ------------------------------------------------------------------

  :with-origin   urn:ietf:params:restconf:capability:with-origin:1.0
	    

8. Normative References

Appendix A. Example

TBD

Authors' Addresses