Internet DRAFT - draft-wwlh-netconf-list-pagination-nc
draft-wwlh-netconf-list-pagination-nc
NETCONF Working Group K. Watsen
Internet-Draft Watsen Networks
Intended status: Standards Track Q. Wu
Expires: 28 April 2022 Huawei
O. Hagsand
Netgate
H. Li
HPE
P. Andersson
Cisco Systems
25 October 2021
NETCONF Extensions to Support List Pagination
draft-wwlh-netconf-list-pagination-nc-02
Abstract
This document defines a mapping of the list pagination mechanism
defined in [I-D.wwlh-netconf-list-pagination] to NETCONF [RFC6241].
This document updates [RFC6241], to augment the <get> and <get-
config> "rpc" statements, and [RFC8526], to augment the <get-data>
"rpc" statement, to define input parameters necessary for list
pagination.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 28 April 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3
2. Updates to NETCONF operations . . . . . . . . . . . . . . . . 3
2.1. Updates to RFC 6241 . . . . . . . . . . . . . . . . . . . 3
2.2. Updates to RFC 8526 . . . . . . . . . . . . . . . . . . . 3
3. List Pagination for NETCONF . . . . . . . . . . . . . . . . . 3
4. Error Reporting . . . . . . . . . . . . . . . . . . . . . . . 4
5. YANG Module for List Pagination in NETCONF . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
6.1. The "IETF XML" Registry . . . . . . . . . . . . . . . . . 7
6.2. The "YANG Module Names" Registry . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7.1. The "ietf-netconf-list-pagination" YANG Module . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Open Issues . . . . . . . . . . . . . . . . . . . . 10
Appendix B. Example YANG Module . . . . . . . . . . . . . . . . 10
Appendix C. Example Data Set . . . . . . . . . . . . . . . . . . 10
Appendix D. Example Queries . . . . . . . . . . . . . . . . . . 10
D.1. List pagination with all query parameters . . . . . . . . 10
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
This document defines a mapping of the list pagination mechanism
defined in [I-D.wwlh-netconf-list-pagination] to NETCONF [RFC6241].
This document updates [RFC6241] and [RFC8526], as described in
Section 2.
While the pagination mechanism defined in this document is designed
for the NETCONF protocol [RFC6241], the augmented RPCs MAY be used by
the RESTCONF protocol [RFC8040] if the RESTCONF server implements the
"ietf-list-pagination-nc" module.
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The YANG data model in this document conforms to the Network
Management Datastore Architecture defined in [RFC8342]
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.
1.2. Conventions
Various examples used in this document use a placeholder value for
binary data that has been base64 encoded (e.g., "BASE64VALUE=").
This placeholder value is used as real base64 encoded structures are
often many lines long and hence distracting to the example being
presented.
2. Updates to NETCONF operations
2.1. Updates to RFC 6241
The <get> and <get-config> rpc statements are augmented to accept
additional input parameters, as described in Section 3.
2.2. Updates to RFC 8526
The <get-data> rpc statement is augmented to accept additional input
parameters, as described in in Section 3.
3. List Pagination for NETCONF
In order for NETCONF to support [I-D.wwlh-netconf-list-pagination],
this document extends the operations <get>, <get-config> and <get-
data> to include additional input parameters and output annotations.
The updated operations accept a content filter parameter, similar to
the "filter" parameter of <get-config>, but includes nodes for "list"
and "leaf-list" filtering.
The content filter parameter is used to specify the YANG list or
leaf-list that is to be retrieved. This must be a path expression
used to represent a list or leaf-list data node.
The following tree diagram [RFC8340] illustrates the "ietf-netconf-
list-pagination" module:
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module: ietf-list-pagination-nc
augment /nc:get/nc:input:
+---w list-pagination
+---w where? union
+---w sort-by? union
+---w direction? enumeration
+---w offset? uint32
+---w limit? union
+---w sublist-limit? union
augment /nc:get-config/nc:input:
+---w list-pagination
+---w where? union
+---w sort-by? union
+---w direction? enumeration
+---w offset? uint32
+---w limit? union
+---w sublist-limit? union
augment /ncds:get-data/ncds:input:
+---w list-pagination
+---w where? union
+---w sort-by? union
+---w direction? enumeration
+---w offset? uint32
+---w limit? union
+---w sublist-limit? union
Comments:
* This module augments three NETCONF "rpc" statements: get, get-
config, and get-data.
* The "get" and "get-config" augments are against the YANG module
defined in [RFC6241]. The "get-data" augment is against the YANG
module defined in [RFC8526].
4. Error Reporting
When an input query parameter is supplied with an erroneous value, an
<rpc-error> MUST be returned containing the error-type value
"application", the error-tag value "invalid-value", and MAY include
the error-severity value "error". Additionally the error-app-tag
SHOULD be set containing query parameter specific error value.
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4.1. The "offset" Query Parameter
If the "offset" query parameter value supplied is larger then the
number of instances in the list or leaf-list target resource, the
<rpc-error> MUST contain error-app-tag with value "offset-out-of-
range".
5. YANG Module for List Pagination in NETCONF
The "ietf-netconf-list-pagination-nc" module defines conceptual
definitions within groupings, which are not meant to be implemented
as datastore contents by a server.
This module has normative references to [RFC6241], [RFC6243],
[RFC6991], and [RFC8342].
<CODE BEGINS> file "ietf-list-pagination-nc@2021-10-25.yang"
module ietf-list-pagination-nc {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-list-pagination-nc";
prefix lpgnc;
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";
}
import ietf-list-pagination {
prefix lp;
reference
"RFC XXXX: List Pagination for YANG-driven Protocols";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>";
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description
"This module augments the <get>, <get-config>, and <get-data>
'rpc' statements to support list pagination.
Copyright (c) 2021 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 Simplified
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 XXXX
(https://www.rfc-editor.org/info/rfcXXXX); 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 2021-10-25 {
description
"Initial revision.";
reference
"RFC XXXX: NETCONF Extensions to Support List Pagination";
}
grouping pagination-parameters {
description "A grouping for list pagination parameters.";
container list-pagination {
description "List pagination parameters.";
uses lp:where-param-grouping;
uses lp:sort-by-param-grouping;
uses lp:direction-param-grouping;
uses lp:offset-param-grouping;
uses lp:limit-param-grouping;
uses lp:sublist-limit-param-grouping;
}
}
augment "/nc:get/nc:input" {
description
"Allow the 'get' operation to use content filter
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parameter for specifying the YANG list or leaf-list
that is to be retrieved";
uses pagination-parameters;
}
augment "/nc:get-config/nc:input" {
description
"Allow the 'get-config' operation to use content filter
parameter for specifying the YANG list or leaf-list
that is to be retrieved";
uses pagination-parameters;
}
augment "/ncds:get-data/ncds:input" {
description
"Allow the 'get-data' operation to use content filter
parameter for specifying the YANG list or leaf-list
that is to be retrieved";
uses pagination-parameters;
}
}
<CODE ENDS>
6. IANA Considerations
6.1. The "IETF XML" Registry
This document registers one URI in the "ns" subregistry of the IETF
XML Registry [RFC3688] maintained at
https://www.iana.org/assignments/xml-registry/xml-registry.xhtml#ns.
Following the format in [RFC3688], the following registration is
requested:
URI: urn:ietf:params:xml:ns:yang:ietf-list-pagination-nc
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
6.2. The "YANG Module Names" Registry
This document registers one YANG module in the YANG Module Names
registry [RFC6020] maintained at https://www.iana.org/assignments/
yang-parameters/yang-parameters.xhtml. Following the format defined
in [RFC6020], the below registration is requested:
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name: ietf-list-pagination-nc
namespace: urn:ietf:params:xml:ns:yang:ietf-list-pagination-nc
prefix: pgnc
RFC: XXXX
7. Security Considerations
7.1. The "ietf-netconf-list-pagination" 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].
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 <get-list-pagination>
RPC operations defined in this document.
8. References
8.1. Normative References
[I-D.wwlh-netconf-list-pagination]
"List Pagination...", <FIXME>.
[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>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[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>.
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[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>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC6243] Bierman, A. and B. Lengyel, "With-defaults Capability for
NETCONF", RFC 6243, DOI 10.17487/RFC6243, June 2011,
<https://www.rfc-editor.org/info/rfc6243>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[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>.
[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>.
[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>.
[RFC8526] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "NETCONF Extensions to Support the Network
Management Datastore Architecture", RFC 8526,
DOI 10.17487/RFC8526, March 2019,
<https://www.rfc-editor.org/info/rfc8526>.
8.2. Informative References
[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>.
[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>.
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[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>.
Appendix A. Open Issues
Cursors (i.e.,stable result sets) are related to the topic of dynamic
changing lists between two queries. How cursors can be supported
using "feature"?
Appendix B. Example YANG Module
The examples within this document use the "example-social" YANG
module defined in Appendix A.1 of [I-D.wwlh-netconf-list-pagination].
Appendix C. Example Data Set
The Example Data Set used by the examples is defined in Appendix A.2
of [I-D.wwlh-netconf-list-pagination].
Appendix D. Example Queries
D.1. List pagination with all query parameters
This example mimics that Appendix A.3.7 of
[I-D.wwlh-netconf-list-pagination].
=============== NOTE: '\' line wrapping per RFC 8792 ================
<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="42">
<get-config>
<source>
<running/>
</source>
<filter type="xpath" select="/es:members/es:member"
xmlns:es="http://example.com/ns/example-social"/>
<list-pagination
xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-list-paginat\
ion">true</list-pagination>
<where>//stats//joined[starts-with(@timestamp,'2020')]</where>
<sort-by>timestamp</sort-by>
<direction>backwards</direction>
<offset>2</offset>
<limit>2</limit>
<sublist-limit>1</sublist-limit>
</filter>
</get-config>
</rpc>
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Response from the NETCONF server:
=============== NOTE: '\' line wrapping per RFC 8792 ================
<lp:xml-list xmlns:lp="urn:ietf:params:xml:ns:yang:ietf-restconf-lis\
t-pagination"
xmlns="http://example.com/ns/example-social">
<member lp:remaining="1">
<member-id>eric</member-id>
<email-address>eric@example.com</email-address>
<password>$0$1543</password>
<avatar>BASE64VALUE=</avatar>
<tagline>Go to bed with dreams; wake up with a purpose.</tagline>
<following>alice</following>
<posts>
<post>
<timestamp>2020-09-17T18:02:04Z</timestamp>
<title>Son, brother, husband, father</title>
<body>What's your story?</body>
</post>
</posts>
<favorites>
<bits lp:remaining="2">two</bits>
</favorites>
<stats>
<joined>2020-09-17T19:38:32Z</joined>
<membership-level>pro</membership-level>
<last-activity>2020-09-17T18:02:04Z</last-activity>
</stats>
</member>
<member lp:remaining="1">
<member-id>bob</member-id>
<email-address>bob@example.com</email-address>
<password>$0$1543</password>
<avatar>BASE64VALUE=</avatar>
<tagline>Here and now, like never before.</tagline>
<posts>
<post lp:remaining="2">
<timestamp>2020-08-14T03:32:25Z</timestamp>
<body>Just got in.</body>
</post>
</posts>
<favorites>
<decimal64-numbers lp:remaining="1">3.14159</bits>
</favorites>
<stats>
<joined>2020-08-14T03:30:00Z</joined>
<membership-level>standard</membership-level>
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<last-activity>2020-08-14T03:34:30Z</last-activity>
</stats>
</member>
</lp:xml-list>
Acknowledgements
This work has benefited from the discussions of RESTCONF resource
collection over the years, in particular, [I-D.ietf-netconf-restconf-
collection] which provides enhanced filtering features for the
retrieval of data nodes with the GET method and [I-D.zheng-netconf-
fragmentation] which document large size data handling challenge.
The authors would like to thank the following for lively discussions
on list:
Andy Bierman Martin Björklund Robert Varga
Authors' Addresses
Kent Watsen
Watsen Networks
Email: kent+ietf@watsen.net
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: bill.wu@huawei.com
Olof Hagsand
Netgate
Email: olof@hagsand.se
Hongwei Li
HPE
Email: flycoolman@gmail.com
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Per Andersson
Cisco Systems
Email: perander@cisco.com
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