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Versions: 00 01

NETCONF Working Group                                          K. Watsen
Internet-Draft                                            Watsen Network
Intended status: Standards Track                                   Q. Wu
Expires: May 6, 2021                                              Huawei
                                                              O. Hagsand
                                                                 Netgate
                                                                   H. Li
                                                                     HPE
                                                        November 2, 2020


             RESTCONF Extensions to Support List Pagination
                draft-wwlh-netconf-list-pagination-rc-01

Abstract

   In some circumstance, a server may contain many instances of a
   particular YANG list or leaf-list.  Retrieval of the entire list or
   leaf-list at once can be extremely inefficient.

   Pagination mechanisms are needed to allow a client to iterate through
   a large list, in a manner that is most efficient for the application.

   This document Updates RFC 8040 to declare "list" and "leaf-list" as
   resource targets for the RESTCONF operations such as GET, POST
   operations.

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 May 6, 2021.








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Copyright Notice

   Copyright (c) 2020 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 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  RESTCONF Extensions . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  RESTCONF Media Type . . . . . . . . . . . . . . . . . . .   4
     2.2.  New Resource Target . . . . . . . . . . . . . . . . . . .   4
   3.  YANG Module for List Pagination . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  The "IETF XML" Registry . . . . . . . . . . . . . . . . .   6
     4.2.  The "YANG Module Names" Registry  . . . . . . . . . . . .   6
     4.3.  The "Media Types" Registry  . . . . . . . . . . . . . . .   6
       4.3.1.  Media Type "application/yang-collection+xml"  . . . .   6
       4.3.2.  Media Type "application/yang-data+xml-list" . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
     5.1.  The "ietf-restconf-list-pagination" YANG Module . . . . .   9
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Appendix A.  Example YANG Module  . . . . . . . . . . . . . . . .  12
   Appendix B.  Example Data . . . . . . . . . . . . . . . . . . . .  12
   Appendix C.  Example Queries  . . . . . . . . . . . . . . . . . .  12
     C.1.  No Query Parameter  . . . . . . . . . . . . . . . . . . .  12
       C.1.1.  XML . . . . . . . . . . . . . . . . . . . . . . . . .  12
       C.1.2.  JSON  . . . . . . . . . . . . . . . . . . . . . . . .  13
     C.2.  Just the "count" Parameter  . . . . . . . . . . . . . . .  13
     C.3.  Just the "skip" Parameter . . . . . . . . . . . . . . . .  14
     C.4.  Just the "direction" Parameter  . . . . . . . . . . . . .  15
     C.5.  Just the "sort" Parameter . . . . . . . . . . . . . . . .  16
     C.6.  Combination of "where" + "count"  . . . . . . . . . . . .  17
     C.7.  Combination of "where" + "skip" + "count" . . . . . . . .  18
     C.8.  Combination of "where" + "sort" + "skip","count"  . . . .  19
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  20



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   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20

1.  Introduction

   There is a need for standard mechanisms to control the filtering,
   sorting, and retrieval of data from the server.  A server may contain
   many instances of a particular YANG list.  Retrieval of the entire
   list or leaf-list at once can be extremely inefficient.

   Pagination mechanisms are needed to allow a client to iterate through
   a large list, in a manner that is most efficient for the application.
   The RPC operation defined in [I-D.wwlh-netconf-list-pagination-nc]
   can be used by the RESTCONF protocol [RFC8040] if the RESTCONF server
   implements the "ietf-yang-list-pagination" module [I-D.wwlh-netconf-
   list-pagination-nc].

   This document Updates RFC 8040 to declare "list" and "leaf-list" as
   resource targets for the RESTCONF operations such as GET, POST
   operations.

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 [RFC8342] [RFC7950] and are not
   redefined here:

   o  server

   o  startup configuration datastore

   o  candidate configuration datastore

   o  running configuration datastore

   o  intended configuration datastore

   o  operational state datastore

   o  conventional configuration datastore

   o  datastore schema

   o  RPC operation



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   The following terms are defined in this document as follows:

2.  RESTCONF Extensions

   This section describes the RESTCONF extensions needed to support the
   Pagination mechanism.

2.1.  RESTCONF Media Type

   The following resource type is defined in this document:

                  +-----------------+-----------------------------+
                  | Resource        | Media Type                  |
                  +-----------------+-----------------------------+
                  | YANG-Collection | application/yang-data+xml-list |
                  | YANG-Collection | application/yang-data+xml-json |
                  +-----------------+-----------------------------+
                              Media Type

2.2.  New Resource Target

   The "get-list-pagination" RPC operation defined in "ietf-yang-list-
   pagination" module [I-D.wwlh-netconf-list-pagination-nc] can use the
   RESTCONF target resource URI to identify the resource that will be
   filtered and returned.  A collection resource contains a set of data
   resources.  It is used to represent all instances or a subset of all
   instances in a YANG list or leaf-list.  A collection resource can be
   used as target resource and retrieved with the GET method or POST
   method.  The "ietf-restconf-list-pagination" YANG module contains the
   "yang-collection" yang data template with the "yang-data"extension
   which specifies the syntax and semantics of a "yang-collection" media
   type.

3.  YANG Module for List Pagination

   The "ietf-restconf-list-pagination" module defines conceptual
   definitions within groupings, which are not meant to be implemented
   as datastore contents by a server.

   <CODE BEGINS> file "ietf-restconf-list-pagination@2020-11-02.yang"

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   module ietf-restconf-list-pagination {
     namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-list-paginati\
   on";
     prefix rlpg;




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     import ietf-restconf {
       prefix rc;
     }

     organization
       "IETF NETCONF (Network Configuration) Working Group";
     contact
       "WG Web:   <http://tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>";

     description
       "This module contains conceptual YANG specifications
        for the RESTCONF Collection resource type.
        Note that the YANG definitions within this module do not
        represent configuration data of any kind.
        The YANG grouping statements provide a normative syntax
        for XML and JSON message encoding purposes.

        Copyright (c) 2015 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
        (http://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX; see
        the RFC itself for full legal notices.";

     revision 2015-01-30 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: RESTCONF Collection Resource.";
     }
     rc:yang-data yang-collection {
       uses collection;
     }

     grouping collection {
       description
         "Conceptual container representing the
          yang-collection resource type.";
       container yang-collection {
         description
           "Container representing the yang-collection



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            resource type.";
       }
     }
   }


   <CODE ENDS>

4.  IANA Considerations

4.1.  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-restconf-list-pagination
     Registrant Contact: The IESG.
     XML: N/A, the requested URI is an XML namespace.

4.2.  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:

    name: ietf-restconf-list-pagination
    namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-list-pagination
    prefix: rlpg
    RFC: xxxx

4.3.  The "Media Types" Registry

   This document registers two media types in the "application"
   subregistry of the Media Types registry [RFC6838] [RFC4855]
   maintained at <https://www.iana.org/assignments/media-types/media-
   types.xhtml#application> Following the format defined in [RFC4855],
   the below registrations are requested:

4.3.1.  Media Type "application/yang-collection+xml"

      Type name: application

      Subtype name: yang-collection+xml




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      Required parameters: None

      Optional parameters: None

      Encoding considerations: 8-bit
         The "utf-8" charset is always used for this type.  Each
         conceptual YANG data node is encoded according to the
         XML Encoding Rules and Canonical Format for the specific
         YANG data node type defined in RFC 7950.

      Security considerations: Security considerations related
         to the generation and consumption of RESTCONF messages
         are discussed in Section 5 of RFC 8072.  Additional
         security considerations are specific to the semantics
         of particular YANG data models.  Each YANG module is
         expected to specify security considerations for the
         YANG data defined in that module.

      Interoperability considerations: RFC 8072 specifies the
         format of conforming messages and the interpretation
         thereof.

      Published specification: RFC 8072

      Applications that use this media type: Instance document
         data parsers used within a protocol or automation tool
         that utilize the YANG Patch data structure.

      Fragment identifier considerations: The syntax and
         semantics of fragment identifiers are the same
         as the syntax and semantics specified for the
         "application/xml" media type.

      Additional information:

         Deprecated alias names for this type: N/A
         Magic number(s): N/A
         File extension(s): None
         Macintosh file type code(s): "TEXT"

      Person & email address to contact for further
         information: See the Authors' Addresses section
         of RFC 8072.

      Intended usage: COMMON

      Restrictions on usage: N/A




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      Author: See the Authors' Addresses section of RFC 8072.

      Change controller: Internet Engineering Task Force
         (mailto:iesg@ietf.org).

      Provisional registration? (standards tree only): no

4.3.2.  Media Type "application/yang-data+xml-list"

     Type name: application

     Subtype name: yang-collection+json

     Required parameters: None

     Optional parameters: None

     Encoding considerations: 8-bit
        The "utf-8" charset is always used for this type.
        Each conceptual YANG data node is encoded according to the
        XML Encoding Rules and Canonical Format for the specific
        YANG data node type defined in RFC 7950.

     Security considerations: Security considerations related
        to the generation and consumption of RESTCONF messages
        are discussed in Section 5 of RFC 8072.
        Additional security considerations are specific to the
        semantics of particular YANG data models.  Each YANG module
        is expected to specify security considerations for the
        YANG data defined in that module.

     Interoperability considerations: RFC 8072 specifies the format
        of conforming messages and the interpretation thereof.

     Published specification: RFC 8072

     Applications that use this media type: Instance document
        data parsers used within a protocol or automation tool
        that utilize the YANG Patch data structure.

     Fragment identifier considerations: The syntax and semantics
        of fragment identifiers are the same as the syntax and semantics
        specified for the "application/xml" media type.

     Additional information:

        Deprecated alias names for this type: N/A
        Magic number(s): N/A



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        File extension(s): None
        Macintosh file type code(s): "TEXT"

     Person & email address to contact for further information: See
        the Authors' Addresses section of RFC 8072.

     Intended usage: COMMON

     Restrictions on usage: N/A

     Author: See the Authors' Addresses section of RFC 8072.

     Change controller: Internet Engineering Task Force
        (mailto:iesg@ietf.org).

     Provisional registration? (standards tree only): no

5.  Security Considerations

5.1.  The "ietf-restconf-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 constraints for the base RESTCONF protocol (see
   Section 12 of [RFC8040]) apply to the new RESTCONF target resources
   defined in this document.

6.  References

6.1.  Normative References

   [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>.






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   [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>.

   [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>.

   [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>.

   [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>.

   [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>.

6.2.  Informative References

   [RFC4855]  Casner, S., "Media Type Registration of RTP Payload
              Formats", RFC 4855, DOI 10.17487/RFC4855, February 2007,
              <https://www.rfc-editor.org/info/rfc4855>.

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, DOI 10.17487/RFC6838, January 2013,
              <https://www.rfc-editor.org/info/rfc6838>.






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   [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>.

   [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>.











































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Appendix A.  Example YANG Module

   The examples within this document use the "example-module" YANG
   module defined in Appendix A of [I-D.wwlh-netconf-list-pagination-
   nc].

Appendix B.  Example Data

   FIXME

Appendix C.  Example Queries

C.1.  No Query Parameter

   Client requests all list entries:

C.1.1.  XML

   Client requests an XML-based Response:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:

   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>




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C.1.2.  JSON

   Client requests a JSON-based Response:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:

   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.2.  Just the "count" Parameter

   In this example, the client requests the first two "skill" resources
   for a given admin resource.

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:






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   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.3.  Just the "skip" Parameter

   In this example, the client requests the next two skills resource,
   i.e., two skills resource starting from two.

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?skip=2&count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:



















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   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.4.  Just the "direction" Parameter

   In this example, the client requests the first two "skill" resources
   in the "forward" direction for a given admin:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?direction=forward&count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:



















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   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.5.  Just the "sort" Parameter

   In this example, the client requests the first 2 "skill" resources
   sorted by name for a given admin:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?sort=name&count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:



















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   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.6.  Combination of "where" + "count"

   In this example, the client requests the first 2 "skill" resources
   from the selected skill resource list for a given admin:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?where=???&count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:



















Watsen, et al.             Expires May 6, 2021                 [Page 17]


Internet-Draft         RESTCONF Pagination Support         November 2020


   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.7.  Combination of "where" + "skip" + "count"

   In this example, the client requests the first 2 "skill" resources
   from the selected "skill" resource list for a given admin:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?where=???&skip=2&count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:



















Watsen, et al.             Expires May 6, 2021                 [Page 18]


Internet-Draft         RESTCONF Pagination Support         November 2020


   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </xml-list>

C.8.  Combination of "where" + "sort" + "skip","count"

   In this example, the client requests the first 2 "skill" resources
   from the selected skill resources list for a given admin:

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   GET /restconf/ds/ietf-datastores:running/example-module:admins/admin\
   =Bob/skill?where=???&sort=name&skip=2&count=2  HTTP/1.1
   Host: example.com
   Accept: application/yang-data+xml-list

   Response from the RESTCONF server:



















Watsen, et al.             Expires May 6, 2021                 [Page 19]


Internet-Draft         RESTCONF Pagination Support         November 2020


   HTTP/1.1 200 OK
   Date: Thu, 26 Jan 2017 20:56:30 GMT
   Server: example-server
   Last-Modified: Thu, 26 Jan 2017 20:55:30 GMT
   Content-Type: application/yang-data+xml-list

   <xml-list xmlns="urn:ietf:params:xml:ns:yang:ietf-list-pagination">
     <skill xmlns="http://example.com/ns/example-module">
       <name>Problem Solving</name>
       <rank>98</rank>
       ...
     </skill>
     <skill xmlns="http://example.com/ns/example-module">
       <name>Conflict Resolution</name>
       <rank>93</rank>
       ...
     </skill>
   </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.  The authors would like
   to thank the following for lively discussions on list (ordered by
   first name): Andy Bierman, Martin Bjoerklund, Robert Varga

Authors' Addresses

   Kent Watsen
   Watsen Network

   EMail: kent+ietf@watsen.net


   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   EMail: bill.wu@huawei.com








Watsen, et al.             Expires May 6, 2021                 [Page 20]


Internet-Draft         RESTCONF Pagination Support         November 2020


   Olof Hagsand
   Netgate

   EMail: olof@hagsand.se


   Hongwei Li
   HPE

   EMail: flycoolman@gmail.com









































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