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NETCONF Working Group                                          K. Watsen
Internet-Draft                                          Juniper Networks
Intended status: Standards Track                        J. Schoenwaelder
Expires: May 7, 2017                            Jacobs University Bremen
                                                        November 3, 2016


                   RESTCONF Client and Server Models
              draft-ietf-netconf-restconf-client-server-01

Abstract

   This document defines two YANG modules, one module to configure a
   RESTCONF client and the other module to configure a RESTCONF server.
   Both modules support the TLS transport protocol with both standard
   RESTCONF and RESTCONF Call Home connections.

Editorial Note (To be removed by RFC Editor)

   This draft contains many placeholder values that need to be replaced
   with finalized values at the time of publication.  This note
   summarizes all of the substitutions that are needed.  No other RFC
   Editor instructions are specified elsewhere in this document.

   This document contains references to other drafts in progress, both
   in the Normative References section, as well as in body text
   throughout.  Please update the following references to reflect their
   final RFC assignments:

   o  draft-ietf-netconf-keystore

   o  draft-ietf-netconf-tls-client-server

   Artwork in this document contains shorthand references to drafts in
   progress.  Please apply the following replacements:

   o  "XXXX" --> the assigned RFC value for this draft

   o  "YYYY" --> the assigned RFC value for draft-ietf-netconf-restconf

   o  "ZZZZ" --> the assigned RFC value for draft-ietf-netconf-tls-
      client-server

   Artwork in this document contains placeholder values for the date of
   publication of this draft.  Please apply the following replacement:

   o  "2016-11-02" --> the publication date of this draft




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   The following two Appendix sections are to be removed prior to
   publication:

   o  Appendix A.  Change Log

   o  Appendix B.  Open Issues

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 http://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 7, 2017.

Copyright Notice

   Copyright (c) 2016 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
   (http://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
     1.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   3
   2.  The RESTCONF Client Model . . . . . . . . . . . . . . . . . .   4
     2.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  YANG Model  . . . . . . . . . . . . . . . . . . . . . . .   4



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   3.  The RESTCONF Server Model . . . . . . . . . . . . . . . . . .   7
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   9
     3.3.  YANG Model  . . . . . . . . . . . . . . . . . . . . . . .  11
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  20
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
     5.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  20
     5.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  20
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  20
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  21
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  21
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  21
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  23
     A.1.  server-model-09 to 00 . . . . . . . . . . . . . . . . . .  23
   Appendix B.  Open Issues  . . . . . . . . . . . . . . . . . . . .  23
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23

1.  Introduction

   This document defines two YANG [RFC6020] modules, one module to
   configure a RESTCONF client and the other module to configure a
   RESTCONF server [draft-ietf-netconf-restconf].  Both modules support
   the TLS [RFC5246] transport protocol with both standard RESTCONF and
   RESTCONF Call Home connections [draft-ietf-netconf-call-home].

1.1.  Terminology

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

1.2.  Tree Diagrams

   A simplified graphical representation of the data models is used in
   this document.  The meaning of the symbols in these diagrams is as
   follows:

   o  Brackets "[" and "]" enclose list keys.

   o  Braces "{" and "}" enclose feature names, and indicate that the
      named feature must be present for the subtree to be present.

   o  Abbreviations before data node names: "rw" means configuration
      (read-write) and "ro" state data (read-only).

   o  Symbols after data node names: "?" means an optional node, "!"
      means a presence container, and "*" denotes a list and leaf-list.




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   o  Parentheses enclose choice and case nodes, and case nodes are also
      marked with a colon (":").

   o  Ellipsis ("...") stands for contents of subtrees that are not
      shown.

2.  The RESTCONF Client Model

   EDITOR NOTE: Please ignore this section, it is incomplete.

   The RESTCONF client model presented in this section supports both
   clients initiating connections to servers, as well as clients
   listening for connections from servers calling home.

   This model supports both TLS transport protocols using the TLS client
   groupings defined in [draft-ietf-netconf-tls-client-server].

   All private keys and trusted certificates are held in the keystore
   model defined in [draft-ietf-netconf-keystore].

   YANG feature statements are used to enable implementations to
   advertise which parts of the model the RESTCONF client supports.

2.1.  Tree Diagram

   Note: all lines are folded at column 71 with no '\' character.

   module: ietf-restconf-client
       +--rw restconf-client
          +--rw initiate {tls-initiate}?
          +--rw listen {tls-listen}?

2.2.  Example Usage

   The following example illustrates configuring a RESTCONF client to
   initiate connections, as well as listening for call-home connections.

   This example is consistent with the examples presented in Section 2.2
   of [draft-ietf-netconf-keystore].

   FIXME

2.3.  YANG Model

   This YANG module imports YANG types from [RFC6991] and [RFC7407].


   <CODE BEGINS> file "ietf-restconf-client@2016-11-02.yang"



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   // Editor's Note:
   // This module is incomplete at this time.  Below is
   // just a skeleton so there's something in the draft.
   // Please ignore this module for now!

   module ietf-restconf-client {
     yang-version 1.1;

     namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-client";
     prefix "rcc";

   /*
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }

     //import ietf-netconf-acm {
     //  prefix nacm;
     //  reference
     //    "RFC 6536: Network Configuration Protocol (NETCONF)
     //     Access Control Model";
     //}

     import ietf-x509-cert-to-name {
       prefix x509c2n;
       reference
         "RFC 7407: A YANG Data Model for SNMP Configuration";
     }

     import ietf-tls-client {
       prefix ts;
       revision-date 2016-11-02; // stable grouping definitions
       reference
         "RFC ZZZZ: TLS Client and Server Models";
     }
   */
     organization
      "IETF NETCONF (Network Configuration) Working Group";

     contact
      "WG Web:   <http://tools.ietf.org/wg/netconf/>
       WG List:  <mailto:netconf@ietf.org>

       WG Chair: Mehmet Ersue
                 <mailto:mehmet.ersue@nsn.com>




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       WG Chair: Mahesh Jethanandani
                 <mailto:mjethanandani@gmail.com>

       Editor:   Kent Watsen
                 <mailto:kwatsen@juniper.net>";


     description
      "This module contains a collection of YANG definitions for
       configuring RESTCONF servers.

       Copyright (c) 2014 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 "2016-11-02" {
       description
        "Initial version";
       reference
        "RFC XXXX: RESTCONF Client and Server Models";
     }

     // Features

     feature tls-initiate {
       description
        "The tls-initiate feature indicates that the RESTCONF client
         supports initiating TLS connections to RESTCONF servers.";
       reference
        "RFC YYYY: RESTCONF Protocol";
     }

     feature tls-listen {
       description
        "The tls-listen feature indicates that the RESTCONF client
         supports opening a port to listen for incoming RESTCONF
         server call-home TLS connections.";
       reference
        "RFC AAAA: NETCONF Call Home and RESTCONF Call Home";



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     }

     container restconf-client {
       description
         "Top-level container for RESTCONF client configuration.";
       container initiate {
         if-feature tls-initiate;
         description
           "Configures client intiating underlying TCP connections.";
       }
       container listen {
         if-feature tls-listen;
         description
           "Configures client accepting call-home TCP connections.";
       }
     }

   }


   <CODE ENDS>

3.  The RESTCONF Server Model

   The RESTCONF Server model presented in this section supports servers
   both listening for connections as well as initiating call-home
   connections.

   This model supports the TLS using the TLS server groupings defined in
   [draft-ietf-netconf-tls-client-server].

   All private keys and trusted certificates are held in the keystore
   model defined in [draft-ietf-netconf-keystore].

   YANG feature statements are used to enable implementations to
   advertise which parts of the model the RESTCONF server supports.

3.1.  Tree Diagram

   Note: all lines are folded at column 71 with no '\' character.

 module: ietf-restconf-server
     +--rw restconf-server
        +--rw listen {listen}?
        |  +--rw max-sessions?   uint16
        |  +--rw endpoint* [name]
        |     +--rw name    string
        |     +--rw (transport)



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        |        +--:(tls) {tls-listen}?
        |           +--rw tls
        |              +--rw address?        inet:ip-address
        |              +--rw port?           inet:port-number
        |              +--rw certificates
        |              |  +--rw certificate* [name]
        |              |     +--rw name    -> /ks:keystore/private-keys/
 private-key/certificate-chains/certificate-chain/name
        |              +--rw client-auth
        |                 +--rw trusted-ca-certs?       -> /ks:keystore/
 trusted-certificates/name
        |                 +--rw trusted-client-certs?   -> /ks:keystore/
 trusted-certificates/name
        |                 +--rw cert-maps
        |                    +--rw cert-to-name* [id]
        |                       +--rw id             uint32
        |                       +--rw fingerprint    x509c2n:tls-fingerp
 rint
        |                       +--rw map-type       identityref
        |                       +--rw name           string
        +--rw call-home {call-home}?
           +--rw restconf-client* [name]
              +--rw name                  string
              +--rw (transport)
              |  +--:(tls) {tls-call-home}?
              |     +--rw tls
              |        +--rw endpoints
              |        |  +--rw endpoint* [name]
              |        |     +--rw name       string
              |        |     +--rw address    inet:host
              |        |     +--rw port?      inet:port-number
              |        +--rw certificates
              |        |  +--rw certificate* [name]
              |        |     +--rw name    -> /ks:keystore/private-keys/
 private-key/certificate-chains/certificate-chain/name
              |        +--rw client-auth
              |           +--rw trusted-ca-certs?       -> /ks:keystore/
 trusted-certificates/name
              |           +--rw trusted-client-certs?   -> /ks:keystore/
 trusted-certificates/name
              |           +--rw cert-maps
              |              +--rw cert-to-name* [id]
              |                 +--rw id             uint32
              |                 +--rw fingerprint    x509c2n:tls-fingerp
 rint
              |                 +--rw map-type       identityref
              |                 +--rw name           string
              +--rw connection-type



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              |  +--rw (connection-type)?
              |     +--:(persistent-connection)
              |     |  +--rw persistent!
              |     |     +--rw keep-alives
              |     |        +--rw max-wait?       uint16
              |     |        +--rw max-attempts?   uint8
              |     +--:(periodic-connection)
              |        +--rw periodic!
              |           +--rw reconnect-timeout?   uint16
              +--rw reconnect-strategy
                 +--rw start-with?     enumeration
                 +--rw max-attempts?   uint8

3.2.  Example Usage

   The following example illustrates configuring a RESTCONF server to
   listen for RESTCONF client connections, as well as configuring call-
   home to one RESTCONF client.

   This example is consistent with the examples presented in Section 2.2
   of [draft-ietf-netconf-keystore].

   <restconf-server
     xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-server">

     <!-- listening for TLS (HTTPS) connections -->
     <listen>
       <endpoint>
         <name>netconf/tls</name>
         <tls>
           <address>11.22.33.44</address>
           <certificates>
             <certificate>ex-key-sect571r1-cert</certificate>
           </certificates>
           <client-auth>
             <trusted-ca-certs>
               deployment-specific-ca-certs
             </trusted-ca-certs>
             <trusted-client-certs>
               explicitly-trusted-client-certs
             </trusted-client-certs>
             <cert-maps>
               <cert-to-name>
                 <id>1</id>
                 <fingerprint>11:0A:05:11:00</fingerprint>
                 <map-type>x509c2n:san-any</map-type>
               </cert-to-name>
               <cert-to-name>



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                 <id>2</id>
                 <fingerprint>B3:4F:A1:8C:54</fingerprint>
                 <map-type>x509c2n:specified</map-type>
                 <name>scooby-doo</name>
               </cert-to-name>
             </cert-maps>
           </client-auth>
         </tls>

       </endpoint>
     </listen>

     <!-- calling home to a RESTCONF client -->
     <call-home>
       <restconf-client>
         <name>config-manager</name>
         <tls>
           <endpoints>
             <endpoint>
               <name>east-data-center</name>
               <address>22.33.44.55</address>
             </endpoint>
             <endpoint>
               <name>west-data-center</name>
               <address>33.44.55.66</address>
             </endpoint>
           </endpoints>
           <certificates>
             <certificate>ex-key-sect571r1-cert</certificate>
           </certificates>
           <client-auth>
             <trusted-ca-certs>
               deployment-specific-ca-certs
             </trusted-ca-certs>
             <trusted-client-certs>
               explicitly-trusted-client-certs
             </trusted-client-certs>
             <cert-maps>
               <cert-to-name>
                 <id>1</id>
                 <fingerprint>11:0A:05:11:00</fingerprint>
                 <map-type>x509c2n:san-any</map-type>
               </cert-to-name>
               <cert-to-name>
                 <id>2</id>
                 <fingerprint>B3:4F:A1:8C:54</fingerprint>
                 <map-type>x509c2n:specified</map-type>
                 <name>scooby-doo</name>



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               </cert-to-name>
             </cert-maps>
           </client-auth>
         </tls>
         <connection-type>
           <periodic>
             <idle-timeout>300</idle-timeout>
             <reconnect-timeout>60</reconnect-timeout>
           </periodic>
         </connection-type>
         <reconnect-strategy>
           <start-with>last-connected</start-with>
           <max-attempts>3</max-attempts>
         </reconnect-strategy>
       </restconf-client>
     </call-home>

   </restconf-server>

3.3.  YANG Model

   This YANG module imports YANG types from [RFC6991] and [RFC7407].


  <CODE BEGINS> file "ietf-restconf-server@2016-11-02.yang"

  module ietf-restconf-server {
    yang-version 1.1;

    namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-server";
    prefix "rcs";

    //import ietf-netconf-acm {
    //  prefix nacm;
    //  reference
    //    "RFC 6536: Network Configuration Protocol (NETCONF)
    //     Access Control Model";
    //}

    import ietf-inet-types {
      prefix inet;
      reference
        "RFC 6991: Common YANG Data Types";
    }

    import ietf-x509-cert-to-name {
      prefix x509c2n;
      reference



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        "RFC 7407: A YANG Data Model for SNMP Configuration";
    }

    import ietf-tls-server {
      prefix ts;
      revision-date 2016-11-02; // stable grouping definitions
      reference
        "RFC ZZZZ: TLS Client and Server Models";
    }

    organization
     "IETF NETCONF (Network Configuration) Working Group";

    contact
     "WG Web:   <http://tools.ietf.org/wg/netconf/>
      WG List:  <mailto:netconf@ietf.org>

      WG Chair: Mehmet Ersue
                <mailto:mehmet.ersue@nsn.com>

      WG Chair: Mahesh Jethanandani
                <mailto:mjethanandani@gmail.com>

      Editor:   Kent Watsen
                <mailto:kwatsen@juniper.net>";


    description
     "This module contains a collection of YANG definitions for
      configuring RESTCONF servers.

      Copyright (c) 2014 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 "2016-11-02" {
      description
       "Initial version";
      reference



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       "RFC XXXX: RESTCONF Client and Server Models";
    }


    // Features

    feature listen {
      description
       "The 'listen' feature indicates that the RESTCONF server
        supports opening a port to accept RESTCONF client connections
        using at least one transport (e.g., TLS, etc.).";
    }

    feature tls-listen {
      description
       "The 'tls-listen' feature indicates that the RESTCONF server
        supports opening a port to listen for incoming RESTCONF
        client connections.";
      reference
       "RFC XXXX: RESTCONF Protocol";
    }

    feature call-home {
      description
       "The 'call-home' feature indicates that the RESTCONF server
        supports initiating RESTCONF call home connections to REETCONF
        clients using at least one transport (e.g., TLS, etc.).";
      reference
       "RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
    }

    feature tls-call-home {
      description
       "The 'tls-call-home' feature indicates that the RESTCONF server
        supports initiating connections to RESTCONF clients.";
      reference
       "RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
    }

    feature client-cert-auth {
      description
       "The client-cert-auth feature indicates that the RESTCONF
        server supports the ClientCertificate authentication scheme.";
      reference
       "RFC ZZZZ: Client Authentication over New TLS Connection";
    }





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    // top-level container
    container restconf-server {
      description
        "Top-level container for RESTCONF server configuration.";

      container listen {
        if-feature listen;
        description
          "Configures listen behavior";
        leaf max-sessions {
          type uint16;
          default 0;   // should this be 'max'?
          description
            "Specifies the maximum number of concurrent sessions
             that can be active at one time.  The value 0 indicates
             that no artificial session limit should be used.";
        }
        list endpoint {
          key name;
          description
            "List of endpoints to listen for RESTCONF connections on.";
          leaf name {
            type string;
            description
              "An arbitrary name for the RESTCONF listen endpoint.";
          }
          choice transport {
            mandatory true;
            description
              "Selects between available transports.";
            case tls {
              if-feature tls-listen;
              container tls {
                description
                  "TLS-specific listening configuration for inbound
                   connections.";
                uses ts:listening-tls-server-grouping {
                  refine port {
                    default 443;
                  }
                  augment "client-auth" {
                    description
                      "Augments in the cert-to-name structure.";
                    uses cert-maps-grouping;
                  }
                }
              }
            }



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          }
        }
      }

      container call-home {
        if-feature call-home;
        description
          "Configures call-home behavior";
        list restconf-client {
          key name;
          description
            "List of RESTCONF clients the RESTCONF server is to
             initiate call-home connections to.";
          leaf name {
            type string;
            description
              "An arbitrary name for the remote RESTCONF client.";
          }
          choice transport {
            mandatory true;
            description
              "Selects between TLS and any transports augmented in.";
            case tls {
              if-feature tls-call-home;
              container tls {
                description
                  "Specifies TLS-specific call-home transport
                   configuration.";
                uses endpoints-container {
                  refine endpoints/endpoint/port {
                    default 4336;
                  }
                }
                uses ts:non-listening-tls-server-grouping {
                  augment "client-auth" {
                    description
                      "Augments in the cert-to-name structure.";
                    uses cert-maps-grouping;
                  }
                }
              }
            }
          }
          container connection-type {
            description
             "Indicates the RESTCONF client's preference for how the
              RESTCONF server's connection is maintained.";
            choice connection-type {



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              description
                "Selects between available connection types.";
              case persistent-connection {
                container persistent {
                  presence true;
                  description
                   "Maintain a persistent connection to the RESTCONF
                    client. If the connection goes down, immediately
                    start trying to reconnect to it, using the
                    reconnection strategy.

                    This connection type minimizes any RESTCONF client
                    to RESTCONF server data-transfer delay, albeit at
                    the expense of holding resources longer.";

                  container keep-alives {
                    description
                      "Configures the keep-alive policy, to proactively
                       test the aliveness of the TLS client.  An
                       unresponsive TLS client will be dropped after
                       approximately (max-attempts * max-wait)
                       seconds.";
                    reference
                      "RFC YYYY: NETCONF Call Home and RESTCONF Call
                       Home, Section 3.1, item S6";
                    leaf max-wait {
                      type uint16 {
                        range "1..max";
                      }
                      units seconds;
                      default 30;
                      description
                       "Sets the amount of time in seconds after which
                        if no data has been received from the TLS
                        client, a TLS-level message will be sent to
                        test the aliveness of the TLS client.";
                    }
                    leaf max-attempts {
                      type uint8;
                      default 3;
                      description
                       "Sets the maximum number of sequential keep-alive
                        messages that can fail to obtain a response from
                        the TLS client before assuming the TLS client is
                        no longer alive.";
                    }
                  }
                }



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              }
              case periodic-connection {
                container periodic {
                  presence true;
                  description
                   "Periodically connect to the RESTCONF client, so that
                    the RESTCONF client may deliver messages pending for
                    the RESTCONF server.  The client must close the
                    connection when it's ready to release it.  Once the
                    connection has been closed, the server will restart
                    its timer until the next connection.";
                  leaf reconnect-timeout {
                    type uint16 {
                      range "1..max";
                    }
                    units minutes;
                    default 60;
                    description
                     "The maximum amount of unconnected time the
                      RESTCONF server will wait before re-establishing
                      a connection to the RESTCONF client.  The
                      RESTCONF server may initiate a connection to
                      the RESTCONF client before this time if desired
                      (e.g., to deliver a notification).";
                  }
                }
              }
            }
          }
          container reconnect-strategy {
            description
             "The reconnection strategy directs how a RESTCONF server
              reconnects to a RESTCONF client after after discovering
              its connection to the client has dropped, even if due to
              a reboot.  The RESTCONF server starts with the specified
              endpoint and tries to connect to it max-attempts times
              before trying the next endpoint in the list (round
              robin).";
            leaf start-with {
              type enumeration {
                enum first-listed {
                  description
                    "Indicates that reconnections should start with
                     the first endpoint listed.";
                }
                enum last-connected {
                  description
                    "Indicates that reconnections should start with



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                     the endpoint last connected to.  If no previous
                     connection has ever been established, then the
                     first endpoint configured is used.   RESTCONF
                     servers SHOULD be able to remember the last
                     endpoint connected to across reboots.";
                }
              }
              default first-listed;
              description
               "Specifies which of the RESTCONF client's endpoints the
                RESTCONF server should start with when trying to connect
                to the RESTCONF client.";
            }
            leaf max-attempts {
              type uint8 {
                range "1..max";
              }
              default 3;
              description
               "Specifies the number times the RESTCONF server tries to
                connect to a specific endpoint before moving on to the
                next endpoint in the list (round robin).";
            }
          }
        }
      }
    }


    grouping cert-maps-grouping {
      description
        "A grouping that defines a container around the
         cert-to-name structure defined in RFC 7407.";
      container cert-maps {
        uses x509c2n:cert-to-name;
        description
         "The cert-maps container is used by a TLS-based RESTCONF
          server to map the RESTCONF client's presented X.509
          certificate to a RESTCONF username.  If no matching and
          valid cert-to-name list entry can be found, then the
          RESTCONF server MUST close the connection, and MUST NOT
          accept RESTCONF messages over it.";
        reference
          "RFC XXXX: The RESTCONF Protocol";
      }
    }





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    grouping endpoints-container {
      description
        "This grouping is used by tls container for call-home
         configurations.";
      container endpoints {
        description
          "Container for the list of endpoints.";
        list endpoint {
          key name;
          min-elements 1;
          ordered-by user;
          description
            "User-ordered list of endpoints for this RESTCONF client.
             Defining more than one enables high-availability.";
          leaf name {
            type string;
            description
              "An arbitrary name for this endpoint.";
          }
          leaf address {
            type inet:host;
            mandatory true;
            description
             "The IP address or hostname of the endpoint.  If a
              hostname is configured and the DNS resolution results
              in more than one IP address, the RESTCONF server
              will process the IP addresses as if they had been
              explicitly configured in place of the hostname.";
          }
          leaf port {
            type inet:port-number;
            description
             "The IP port for this endpoint. The RESTCONF server will
              use the IANA-assigned well-known port if no value is
              specified.";
          }
        }
      }
    }


  }


  <CODE ENDS>






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4.  Security Considerations

5.  IANA Considerations

5.1.  The IETF XML Registry

   This document registers two URIs in the IETF XML registry [RFC2119].
   Following the format in [RFC3688], the following registrations are
   requested:

      URI: urn:ietf:params:xml:ns:yang:ietf-restconf-client
      Registrant Contact: The NETCONF WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

      URI: urn:ietf:params:xml:ns:yang:ietf-restconf-server
      Registrant Contact: The NETCONF WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

5.2.  The YANG Module Names Registry

   This document registers two YANG modules in the YANG Module Names
   registry [RFC6020].  Following the format in [RFC6020], the the
   following registrations are requested:

      name:         ietf-restconf-client
      namespace:    urn:ietf:params:xml:ns:yang:ietf-restconf-client
      prefix:       ncc
      reference:    RFC XXXX

      name:         ietf-restconf-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-restconf-server
      prefix:       ncs
      reference:    RFC XXXX

6.  Acknowledgements

   The authors would like to thank for following for lively discussions
   on list and in the halls (ordered by last name): Andy Bierman, Martin
   Bjorklund, Benoit Claise, Mehmet Ersue, David Lamparter, Alan Luchuk,
   Ladislav Lhotka, Radek Krejci, Tom Petch, Phil Shafer, Sean Turner,
   and Bert Wijnen.

   Juergen Schoenwaelder and was partly funded by Flamingo, a Network of
   Excellence project (ICT-318488) supported by the European Commission
   under its Seventh Framework Programme.






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7.  References

7.1.  Normative References

   [draft-ietf-netconf-keystore]
              Watsen, K., "Keystore Model", draft-ieft-netconf-
              keystore-00 (work in progress), 2016,
              <https://datatracker.ietf.org/html/draft-ieft-netconf-
              keystore>.

   [draft-ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ieft-netconf-restconf-13 (work in
              progress), 2016, <https://datatracker.ietf.org/html/draft-
              ieft-netconf-restconf>.

   [draft-ietf-netconf-tls-client-server]
              Watsen, K., "TLS Client and Server Models", draft-ieft-
              netconf-tls-client-server-00 (work in progress), 2016,
              <https://datatracker.ietf.org/html/draft-ieft-netconf-tls-
              client-server>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://www.rfc-editor.org/info/rfc6020>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <http://www.rfc-editor.org/info/rfc6991>.

   [RFC7407]  Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for
              SNMP Configuration", RFC 7407, DOI 10.17487/RFC7407,
              December 2014, <http://www.rfc-editor.org/info/rfc7407>.

7.2.  Informative References

   [draft-ietf-netconf-call-home]
              Watsen, K., "NETCONF Call Home and RESTCONF Call Home",
              draft-ieft-netconf-call-home-17 (work in progress), 2015,
              <https://datatracker.ietf.org/html/draft-ieft-netconf-
              call-home-17>.




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   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <http://www.rfc-editor.org/info/rfc3688>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <http://www.rfc-editor.org/info/rfc5246>.











































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Appendix A.  Change Log

A.1.  server-model-09 to 00

   o  This draft was split out from draft-ietf-netconf-server-model-09.

   o  Added in new features 'listen' and 'call-home' so future
      transports can be augmented in.

Appendix B.  Open Issues

   Please see: https://github.com/netconf-wg/restconf-client-server/
   issues.

Authors' Addresses

   Kent Watsen
   Juniper Networks

   EMail: kwatsen@juniper.net


   Juergen Schoenwaelder
   Jacobs University Bremen

   EMail: j.schoenwaelder@jacobs-university.de

























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