NETCONF Working Group                                          K. Watsen
Internet-Draft                                          Juniper Networks
Intended status: Standards Track                        J. Schoenwaelder
Expires: August 6, 2015 January 7, 2016                        Jacobs University Bremen
                                                        February 2,
                                                            July 6, 2015

        NETCONF Server and RESTCONF Server Configuration Models
                   draft-ietf-netconf-server-model-06
                   draft-ietf-netconf-server-model-07

Abstract

   This draft defines a NETCONF server configuration data model and a
   RESTCONF server configuration data model.  These data models enable
   configuration of the NETCONF and RESTCONF services themselves,
   including which transports are supported, what ports the servers
   listens
   listen on, whether call-home is supported, parameters, client authentication, and associated other
   related configuration parameters.

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.  Please note
   that no other RFC Editor instructions are specified anywhere else 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-rfc5539bis

   o  draft-ietf-netconf-restconf

   o  draft-ietf-netconf-call-home

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

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

   o  "WWWW" --> the assigned RFC value for draft-ietf-netconf-
      rfc5539bis

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

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

   o  "ZZZZ" --> the assigned RFC value for draft-thomson-httpbis-cant
   Artwork in this document contains placeholder values for ports
   pending IANA assignment from "draft-ietf-netconf-call-home".  Please
   apply the following replacements:

   o  "7777" --> the assigned port value for "netconf-ch-ssh"

   o  "8888" --> the assigned port value for "netconf-ch-tls"

   o  "9999" --> the assigned port value for "restconf-ch-tls"

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

   o  "2015-02-02"  "2015-07-06" --> the publication date of this draft

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

   o  Appendix B.  Change Log

   o  Appendix C.  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 August 6, 2015. January 7, 2016.

Copyright Notice

   Copyright (c) 2015 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   4   5
   2.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  Support all NETCONF and RESTCONF transports . . . . . . .   5
     2.2.  Enable each transport to select which keys to use . . . .   5
     2.3.  Support authenticating NETCONF/RESTCONF clients
           certificates  . . . . . . . . . . . . . . . . . . . . . .   5   6
     2.4.  Support mapping authenticated NETCONF/RESTCONF client
           certificates to usernames . . . . . . . . . . . . . . . .   6
     2.5.  Support both Listening listening for connections and Call Home call home  . .   6
     2.6.  For Call Home connections . . . . . . . . . . . . . . . .   6
       2.6.1.  Support more than one northbound application NETCONF/RESTCONF client . . . .   6
       2.6.2.  Support applications NETCONF/RESTCONF clients having more than one server
               endpoint  . . . . . . . . . . . . . . . . . . . . . .   6
       2.6.3.  Support a reconnection strategy . . . . . . . . . . .   6   7
       2.6.4.  Support both persistent and periodic connections  . .   7
       2.6.5.  Reconnection strategy for periodic connections  . . .   7
       2.6.6.  Keep-alives for persistent connections  . . . . . . .   7
       2.6.7.  Customizations for periodic connections . . . . . . .   7   8
   3.  The NETCONF Server Configuration Model  . . . . . . . . . . .   8
     3.1.  Overview . . . . . . .   8
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   8
       3.1.1.  The "session-options" subtree
     3.2.  Example Usage . . . . . . . . . . . .   8
       3.1.2.  The "listen" subtree . . . . . . . . . .   9
       3.2.1.  Configuring SSH Transport . . . . . .   8
       3.1.3.  The "call-home" subtree . . . . . . . .  10
       3.2.2.  Configuring TLS Transport . . . . . . .   9
       3.1.4.  The "ssh" subtree . . . . . . .  11
     3.3.  YANG Model  . . . . . . . . . . .  11
       3.1.5.  The "tls" subtree . . . . . . . . . . . .  13
   4.  The RESTCONF Server Model . . . . . .  11
     3.2.  YANG Module . . . . . . . . . . . .  26
     4.1.  Tree Diagram  . . . . . . . . . . .  12
   4.  The RESTCONF Server Configuration Model . . . . . . . . . . .  25
     4.1.  Overview  26
     4.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .  27
       4.2.1.  Configuring TLS Transport . .  25
       4.1.1.  The "listen" subtree . . . . . . . . . . . .  27
     4.3.  YANG Model  . . . .  25
       4.1.2.  The "call-home" subtree . . . . . . . . . . . . . . .  26
       4.1.3.  The "client-cert-auth" subtree . . . .  28
   5.  Security Considerations . . . . . . .  28
     4.2.  YANG Module . . . . . . . . . . . .  37
   6.  IANA Considerations . . . . . . . . . . .  28
   5.  Implementation strategy for keep-alives . . . . . . . . . .  38
   7.  Other Considerations  .  39
     5.1.  Keep-alives for SSH . . . . . . . . . . . . . . . . . . .  39
     5.2.  Keep-alives for TLS
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . .  40

   6.  Security Considerations . . .  39
   9.  References  . . . . . . . . . . . . . . . .  40
   7.  IANA Considerations . . . . . . . . .  39
     9.1.  Normative References  . . . . . . . . . . . .  41
   8.  Other Considerations . . . . . .  39
     9.2.  Informative References  . . . . . . . . . . . . . .  41
   9.  Acknowledgements . . .  40
   Appendix A.  Alternative solution addressing Issue #49  . . . . .  41
     A.1.  The Keychain Model  . . . . . . . . . . . . . . . .  42
   10. References . . .  41
       A.1.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . .  41
       A.1.2.  Example Usage . .  42
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  42
     10.2.  Informative References
       A.1.3.  YANG Model  . . . . . . . . . . . . . . . . .  43
   Appendix A.  Examples . . . .  45
     A.2.  The SSH Server Model  . . . . . . . . . . . . . . . . . .  44
     A.1.  NETCONF Configuration using SSH Transport  52
       A.2.1.  Tree Diagram  . . . . . . . .  44
     A.2.  NETCONF Configuration using TLS Transport . . . . . . . .  45
     A.3.  RESTCONF Configuration using TLS Transport . . . .  52
       A.2.2.  Example Usage . . .  47
   Appendix B.  Change Log . . . . . . . . . . . . . . . . .  53
       A.2.3.  YANG Model  . . . .  47
     B.1.  00 to 01 . . . . . . . . . . . . . . . . .  53
     A.3.  The TLS Server Model  . . . . . . .  47
     B.2.  01 to 02 . . . . . . . . . . .  56
       A.3.1.  Tree Diagram  . . . . . . . . . . . . .  48
     B.3.  02 to 03 . . . . . . .  56
       A.3.2.  Example Usage . . . . . . . . . . . . . . . . .  48
     B.4.  03 . . .  57
       A.3.3.  YANG Model  . . . . . . . . . . . . . . . . . . . . .  57
     A.4.  The NETCONF Server Model  . . . . . . . . . . . . . . . .  60
       A.4.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . .  60
       A.4.2.  Example Usage . . . . . . . . . . . . . . . . . . . .  62
       A.4.3.  YANG Model  . . . . . . . . . . . . . . . . . . . . .  64
     A.5.  The RESTCONF Server Model . . . . . . . . . . . . . . . .  75
       A.5.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . .  75
       A.5.2.  Example Usage . . . . . . . . . . . . . . . . . . . .  76
       A.5.3.  YANG Model  . . . . . . . . . . . . . . . . . . . . .  76
   Appendix B.  Change Log . . . . . . . . . . . . . . . . . . . . .  84
     B.1.  00 to 04 01  . . . . . . . . . . . . . . . . . . . . . . . .  48
     B.5.  04  84
     B.2.  01 to 05 02  . . . . . . . . . . . . . . . . . . . . . . . .  48
     B.6.  05  84
     B.3.  02 to 06 03  . . . . . . . . . . . . . . . . . . . . . . . .  49
   Appendix C.  Open Issues  84
     B.4.  03 to 04  . . . . . . . . . . . . . . . . . . . .  49

1.  Introduction

   This draft defines a NETCONF [RFC6241] server . . . .  84
     B.5.  04 to 05  . . . . . . . . . . . . . . . . . . . . . . . .  85
     B.6.  05 to 06  . . . . . . . . . . . . . . . . . . . . . . . .  85
     B.7.  06 to 07  . . . . . . . . . . . . . . . . . . . . . . . .  86
   Appendix C.  Open Issues  . . . . . . . . . . . . . . . . . . . .  87

1.  Introduction

   This draft defines a NETCONF [RFC6241] server configuration data
   model and a RESTCONF [draft-ietf-netconf-restconf] server
   configuration data model.  These data models enable configuration of
   the NETCONF and RESTCONF services themselves, including which
   transports are supported, what ports the servers listens listen on, whether call-home is supported,
   parameters, client authentication, and associated other related configuration
   parameters.

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.

   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.  Objectives

   The primary purpose of the YANG modules defined herein is to enable
   the configuration of the NETCONF and RESTCONF services on a network
   element.  This scope includes the following objectives:

2.1.  Support all NETCONF and RESTCONF transports

   The YANG module should support all current NETCONF and RESTCONF
   transports, namely NETCONF over SSH [RFC6242], NETCONF over TLS
   [draft-ietf-netconf-rfc5539bis],
   [RFC7589], and RESTCONF over TLS [draft-ietf-netconf-restconf], and
   to be extensible to support future transports as necessary.

   Because implementations may not support all transports, the module
   should use YANG "feature" statements so that implementations can
   accurately advertise which transports are supported.

2.2.  Enable each transport to select which keys to use

   Servers may have a multiplicity of host-keys or server-certificates
   from which subsets may be selected for specific uses.  For instance,
   a NETCONF server may want to use one set of SSH host-keys when
   listening on port 830, and a different set of SSH host-keys when
   calling home.  The data models provided herein should enable
   configuration of which keys to use on a per-use basis.

2.3.  Support authenticating NETCONF/RESTCONF clients certificates

   When a certificate is used to authenticate a NETCONF or RESTCONF
   client, there is a need to configure the server to know how to
   authenticate the certificates.  The server should be able to
   authenticate the client's certificate either by using path-validation
   to a configured trust anchor or by matching the client-certificate to
   one previously configured.

2.4.  Support mapping authenticated NETCONF/RESTCONF client certificates
      to usernames

   When a client certifcate certificate is used for TLS transport-level client authentication, the
   NETCONF/RESTCONF server must be able to derive a username from the
   authenticated certifcate. certificate.  Thus the modules defined herein should
   enable this mapping to be configured.

2.5.  Support both Listening listening for connections and Call Home call home

   The NETCONF and RESTCONF protocols were originally defined as having
   the server opening a port to listen for client connections.  More
   recently the NETCONF working group defined support for call-home
   ([draft-ietf-netconf-call-home]), enabling the server to initiate the
   connection to the client, for both the NETCONF and RESTCONF
   protocols.  Thus the modules defined herein should enable
   configuration for both listening for connections and calling home.
   Because implementations may not support both listening for
   connections and calling home, YANG "feature" statements should be
   used so that implementation can accurately advertise the connection
   types it supports.

2.6.  For Call Home connections

   The following objectives only pertain to call home connections.

2.6.1.  Support more than one northbound application NETCONF/RESTCONF client

   A device NETCONF/RESTCONF server may be managed by more than one northbound application. NETCONF/
   RESTCONF client.  For instance, a deployment may have one application client for
   provisioning and another for fault monitoring.  Therefore, when it is
   desired for a
   device server to initiate call home connections, it should be
   able to do so to more than one application. client.

2.6.2.  Support applications NETCONF/RESTCONF clients having more than one server endpoint

   An application NETCONF/RESTCONF client managing a device NETCONF/RESTCONF server may
   implement a high-availability strategy employing a multiplicity of
   active and/or passive servers. endpoint.  Therefore, when it is desired for a device
   server to initiate call home connections, it should be able to
   connect to any of the application's
   servers. client's endpoints.

2.6.3.  Support a reconnection strategy

   Assuming an application a NETCONF/RESTCONF client has more than one server, endpoint, then
   it becomes necessary to configure how a device NETCONF/RESTCONF server
   should reconnect to the
   application client should it lose its connection to one
   the application's
   servers.  Of primary interest is if client's endpoints.  For instance, the device should NETCONF/RESTCONF server
   may start with first server endpoint defined in a user-ordered list of servers
   endpoints or with the thei last server endpoints it was connected to.  Secondary settings might specify
   the frequency of attempts and number of attempts per server.
   Therefore, a reconnection strategy should be configurable.

2.6.4.  Support both persistent and periodic connections

   Applications

   NETCONF/RESTCONF clients may vary greatly on how frequently they need
   to interact with a device, NETCONF/RESTCONF server, how responsive
   interactions with devices need to be, and how many simultaneous connections they
   can support.  Some
   applications clients may need a persistent connection to devices
   servers to optimize real-time interactions, while others prefer
   periodic interactions in order to minimize resource requirements.
   Therefore, when it is necessary for devices server to initiate connections, the type of connection
   desired
   it should be configurable. configurable if the connection is persistent or
   periodic.

2.6.5.  Reconnection strategy for periodic connections

   The reconnection strategy should apply to both persistent and
   periodic connections.  How it applies to periodic connections becomes
   clear when considering that a periodic "connection" is a logical
   connection to a single server.  That is, the periods of
   unconnectedness are intentional as opposed to due to external
   reasons.  A periodic "connection" should always reconnect to the same
   server until it is no longer able to, at which time the reconnection
   strategy guides how to connect to another server.

2.6.6.  Keep-alives for persistent connections

   If a persistent connection is desired, it is the responsibility of
   the connection initiator to actively test the "aliveness" of the
   connection.  The connection initiator must immediately work to
   reestablish a persistent connection as soon as the connection is
   lost.  How often the connection should be tested is driven by
   application
   NETCONF/RESTCONF client requirements, and therefore keep-alive
   settings should be configurable on a per-application per-client basis.

2.6.7.  Customizations for periodic connections

   If a periodic connection is desired, it is necessary for the device NETCONF/
   RESTCONF server to know how often it should connect.  This delay essentially frequency
   determines how long the application might maximum amount of time a NETCONF/RESTCONF client may
   have to wait to send data to the device.  This setting does not constrain how often the device
   must wait to send data a server.  A server may connect to the application, as the device should
   immediately connect to the application whenever it has data to send
   to it.

   A common communication pattern is that one data transmission is many
   times closely followed by another.  For instance, a
   client before this interval expires if the device needs desired (e.g., to send a notification message, there's a high probability that it
   will send another shortly thereafter.  Likewise, the application may
   have a sequence of pending messages to send.  Thus, it should be
   possible for a device data to hold
   a connection open until some amount of
   time of no data being transmitted as transpired. client).

3.  The NETCONF Server Configuration Model

3.1.  Overview

3.1.1.  The "session-options" subtree  Tree Diagram

   module: ietf-netconf-server
      +--rw netconf-server
         +--rw session-options
         |  +--rw hello-timeout?   uint32
            +--rw idle-timeout?    uint32

   The above subtree illustrates how the ietf-netconf-server YANG module
   enables configuration of NETCONF session options, independent of any
   transport or connection strategy.  Please see the YANG module
   (Section 3.2) for a complete description of these configuration
   knobs.

3.1.2.  The "listen" subtree
   module: ietf-netconf-server
      +--rw netconf-server   uint16
         +--rw listen {listen}? {(ssh-listen or tls-listen)}?
         |  +--rw max-sessions?   uint16
         |  +--rw idle-timeout?   uint16
         |  +--rw endpoint* [name]
         |     +--rw name    string
         |     +--rw (transport)
         |        +--:(ssh) {ssh}? {ssh-listen}?
         |        |  +--rw ssh
         |        |     +--rw address?     inet:ip-address
         |        |     +--rw port?        inet:port-number
         |        |     +--rw host-keys
         |        |        +--rw host-key*   string
         |        +--:(tls) {tls}? {tls-listen}?
         |           +--rw tls
         |              +--rw address?        inet:ip-address
         |              +--rw port?           inet:port-number
         |              +--rw certificates
         |                 +--rw certificate*   string
         +--rw keep-alives
                  +--rw interval-secs?   uint8
                  +--rw count-max?       uint8

   The above subtree illustrates how the ietf-netconf-server YANG module
   enables configuration for listening for remote connections, as
   described in [RFC6242].  Feature statements are used to limit both if
   listening is supported at all as well as for which transports.  If
   listening for connections is supported, then the model enables
   configuring a list of listening endpoints, each configured with a
   user-specified name (the key field), the transport to use (i.e.  SSH,
   TLS), and the IP address and port to listen on.  The port field is
   optional, defaulting to the transport-specific port when not
   configured.  Please see the YANG module (Section 3.2) for a complete
   description of these configuration knobs.

3.1.3.  The "call-home" subtree
   module: ietf-netconf-server
      +--rw netconf-server
         +--rw call-home {call-home}? {(ssh-call-home or tls-call-home)}?
         |  +--rw application* netconf-client* [name]
         |     +--rw name                  string
         |     +--rw (transport)
         |     |  +--:(ssh) {ssh}? {ssh-call-home}?
         |     |  |  +--rw ssh
         |     |  |     +--rw endpoints
         |     |  |     |  +--rw endpoint* [name]
         |     |  |     |     +--rw name       string
         |     |  |     |     +--rw address    inet:host
         |     |  |     |     +--rw port?      inet:port-number
         |     |  |     +--rw host-keys
         |     |  |        +--rw host-key*   string
         |     |  +--:(tls) {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*   string
         |     +--rw connection-type
         |     |  +--rw (connection-type)?
         |     +--:(persistent-connection)     |     +--:(persistent-connection)
         |  +--rw persistent     |     |  +--rw keep-alives persistent!
         |     |     |     +--rw interval-secs?   uint8 idle-timeout?   uint32
         |     |     |     +--rw keep-alives
         |     |     |        +--rw max-wait?       uint16
         |     |     |        +--rw count-max? max-attempts?   uint8
         |     |     +--:(periodic-connection)
         |     |        +--rw periodic periodic!
         |     |           +--rw timeout-mins?   uint8 idle-timeout?        uint16
         |     |           +--rw linger-secs?    uint8 reconnect_timeout?   uint16
         |     +--rw reconnect-strategy
         |        +--rw start-with?     enumeration
         |        +--rw interval-secs?   uint8
                  +--rw count-max? max-attempts?   uint8

   The above subtree illustrates how the ietf-netconf-server YANG module
   enables configuration for call home, as described in
   [draft-ietf-netconf-call-home].  Feature statements are used to limit
   both if call-home is supported at all as well as for which
   transports, if it is.  If call-home is supported, then the model
   supports configuring a list of applications to connect to.  Each
   application is configured with a user-specified name (the key field),
   the transport to be used (i.e.  SSH, TLS), and a list of remote
   endpoints, each having a name, an IP address, and an optional port.
   Additionally, the configuration for each remote application indicates
   the connection-type (persistent vs. periodic) and associated
   parameters, as well as the reconnection strategy to use.  Please see
   the YANG module (Section 3.2) for a complete description of these
   configuration knobs.

3.1.4.  The "ssh" subtree

   module: ietf-netconf-server
      +--rw netconf-server
         +--rw ssh {ssh}? {(ssh-listen or ssh-call-home)}?
         |  +--rw x509 {ssh-x509-certs}?
         |     +--rw trusted-ca-certs
         |     |  +--rw trusted-ca-cert*   binary
         |     +--rw trusted-client-certs
         |        +--rw trusted-client-cert*   binary

   The above subtree illustrates how the ietf-netconf-server YANG module
   enables some SSH configuration independent of if the NETCONF server
   is listening or calling home.  Specifically, when RFC 6187 is
   supported, this data model provides an ability to configure how
   client-certificates are authenticated.  Please see the YANG module
   (Section 3.2) for a complete description of these configuration
   knobs.

3.1.5.  The "tls" subtree

   module: ietf-netconf-server
      +--rw netconf-server
         +--rw tls {tls}? {(tls-listen or tls-call-home)}?
            +--rw client-auth
               +--rw trusted-ca-certs
               |  +--rw trusted-ca-cert*   binary
               +--rw trusted-client-certs
               |  +--rw trusted-client-cert*   binary
               +--rw cert-maps
                  +--rw cert-to-name* [id]
                     +--rw id             uint32
                     +--rw fingerprint    x509c2n:tls-fingerprint
                     +--rw map-type       identityref
                     +--rw name           string

3.2.  Example Usage
3.2.1.  Configuring SSH Transport

   The above subtree following example illustrates how the ietf-netconf-server YANG module
   enables TLS configuration independent of if the <get> response from a NETCONF
   server is that only supports SSH, both listening or for incoming
   connections as well as calling home.  Specifically, this data-model provides 1)
   an ability to configure how client-certificates are authenticated and
   2) how authenticated client-certificates are mapped home to NETCONF user
   names.  Please see a single NETCONF/RESTCONF
   client having two endpoints.

<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
  <listen>
    <endpoint>
      <name>netconf/ssh</name>
      <ssh>
        <address>11.22.33.44</address>
        <host-keys>
          <host-key>my-rsa-key</host-key>
          <host-key>my-dss-key</host-key>
        </host-keys>
      </ssh>
    </endpoint>
  </listen>
  <call-home>
    <netconf-client>
      <name>config-mgr</name>
      <ssh>
        <endpoints>
          <endpoint>
            <name>east-data-center</name>
            <address>11.22.33.44</address>
          </endpoint>
          <endpoint>
            <name>west-data-center</name>
            <address>55.66.77.88</address>
          </endpoint>
        </endpoints>
        <host-keys>
          <host-key>my-call-home-x509-key</host-key>
        </host-keys>
      </ssh>
    </netconf-client>
  </call-home>
  <ssh>
    <x509>
      <trusted-ca-certs>
        <trusted-ca-cert>
          QW4gRWFzdGVyIGVnZywgZm9yIHRob3NlIHdobyBtaWdodCBsb29rICA6KQo=
        </trusted-ca-cert>
      </trusted-ca-certs>
      <trusted-client-certs>
        <trusted-client-cert>
          SSBhbSB0aGUgZWdnIG1hbiwgdGhleSBhcmUgdGhlIGVnZyBtZW4uCg==
        </trusted-client-cert>
        <trusted-client-cert>
          SSBhbSB0aGUgd2FscnVzLCBnb28gZ29vIGcnam9vYi4K
        </trusted-client-cert>
      </trusted-client-certs>
    </x509>
  </ssh>
</netconf-server>

3.2.2.  Configuring TLS Transport

   The following example illustrates the YANG module (Section 3.2) <get> response from a NETCONF
   server that only supports TLS, both listening for incoming
   connections as well as calling home to a complete
   description of these configuration knobs.

3.2. single NETCONF/RESTCONF
   client having two endpoints.  Please note also the configurations for
   authenticating client certificates and mappings authenticated
   certificates to NETCONF user names.

<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server"
     xmlns:x509c2n="urn:ietf:params:xml:ns:yang:ietf-x509-cert-to-name">
  <listen>
    <endpoint>
      <name>netconf/tls</name>
      <tls>
        <address>11.22.33.44</address>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </endpoint>
  </listen>
  <call-home>
    <netconf-client>
      <name>config-mgr</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>IDevID Certificate</certificate>
        </certificates>
      </tls>
    </netconf-client>
  </call-home>
  <tls>
    <client-auth>
      <trusted-ca-certs>
        <trusted-ca-cert>
          WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
          lLQllsdWpOcjFTMnRLR05EMUc2OVJpK2FWNGw2NTdZNCtadVJMZgpRYjk
          zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
          NGcEk3UE90cnNFVjRwTUNBd0VBQWFPQ0FSSXdnZ0VPCk1CMEdBMVVkRGd
          VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
          V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
          NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
          Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
          WpiMjB2WlhoaGJYQnNaUzVqY215aU9LUTJNRFF4Q3pBSkJnTlZCQVlUQW
          QmdOVkJBWVRBbFZUTVJBd0RnWURWUVFLRXdkbAplR0Z0Y0d4bE1RNHdEQ
          MkF6a3hqUDlVQWtHR0dvS1U1eUc1SVR0Wm0vK3B0R2FieXVDMjBRd2kvZ
          25PZnpZNEhONApXY0pTaUpZK2xtYWs3RTRORUZXZS9RdGp4NUlXZmdvN2
          RJSUJQFRStS0Cg==
        </trusted-ca-cert>
      </trusted-ca-certs>
      <trusted-client-certs>
        <trusted-client-cert>
          QmdOVkJBWVRBbFZUTVJBd0RnWURWUVFLRXdkbAplR0Z0Y0d4bE1RNHdEQ
          MkF6a3hqUDlVQWtHR0dvS1U1eUc1SVR0Wm0vK3B0R2FieXVDMjBRd2kvZ
          25PZnpZNEhONApXY0pTaUpZK2xtYWs3RTRORUZXZS9RdGp4NUlXZmdvN2
          RV0JCU2t2MXI2SFNHeUFUVkpwSmYyOWtXbUU0NEo5akJrQmdOVkhTTUVY
          VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
          UxNQWtHQTFVRUJoTUNWVk14RURBT0JnTlZCQW9UQjJWNApZVzF3YkdVeE
          V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
          NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
          Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
          WpiMjB2WlhoaGJYQnNaUzVqY215aU9LUTJNRFF4Q3pBSkJnTlZCQVlUQW
          xWVE1SQXdEZ1lEVlFRSwpFd2RsZUdGdGNHeGxNUk13RVFZRFZRUURFd3B
          EVWt3Z1NYTnpkV1Z5TUEwR0NTcUdTSWIzRFFFQkJRVUFBNEdCCkFFc3BK
          WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
          TQzcjFZSjk0M1FQLzV5eGUKN2QxMkxCV0dxUjUrbEl5N01YL21ka2M4al
          zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
          LS0tLUVORCBDRVJUSUZJQ0FURS0tLS0tCg==
        </trusted-client-cert>
        <trusted-client-cert>
          VlEVlFRREV3Vm9ZWEJ3ZVRDQm56QU5CZ2txaGtpRzl3MEJBUUVGQUFPQm
          pRQXdnWWtDCmdZRUE1RzRFSWZsS1p2bDlXTW44eUhyM2hObUFRaUhVUzV
          rRUpPQy9hSFA3eGJXQW1ra054ZStUa2hrZnBsL3UKbVhsTjhSZUd1ODhG
          NGcEk3UE90cnNFVjRwTUNBd0VBQWFPQ0FSSXdnZ0VPCk1CMEdBMVVkRGd
          VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
          V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
          NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
          Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
          WpiMjB2WlhoaGJYQnNaUzVqY215aU9LUTJNRFF4Q3pBSkJnTlZCQVlUQW
          xWVE1SQXdEZ1lEVlFRSwpFd2RsZUdGdGNHeGxNUk13RVFZRFZRUURFd3B
          EVWt3Z1NYTnpkV1Z5TUEwR0NTcUdTSWIzRFFFQkJRVUFBNEdCCkFFc3BK
          WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
          lLQllsdWpOcjFTMnRLR05EMUc2OVJpK2FWNGw2NTdZNCtadVJMZgpRYjk
          zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
          QWtUOCBDRVUUZJ0RUF==
        </trusted-client-cert>
      </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>
        </cert-to-name>
      </cert-maps>
    </client-auth>
  </tls>
</netconf-server>

3.3.  YANG Module Model

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

<CODE BEGINS> file "ietf-netconf-server@2015-02-02.yang" "ietf-netconf-server@2015-07-06.yang"

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

  namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-server";
  prefix "ncserver";

  import ietf-netconf-acm {
    prefix nacm;                     // RFC 6536
    revision-date 2012-02-22;
  }
  import ietf-inet-types {           // RFC 6991
    prefix inet;
    revision-date 2013-07-15;
  }
  import ietf-x509-cert-to-name {    // RFC 7407
    prefix x509c2n;
    revision-date 2014-12-10;
  }

  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 NETCONF 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 VVVV; see
    the RFC itself for full legal notices.";

  revision "2015-02-02" "2015-07-06" {
    description
     "Initial version";
    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }
  // Features

  feature ssh ssh-listen {
    description
     "The ssh ssh-listen feature indicates that the NETCONF server
      supports the opening a port to accept NETCONF over SSH transport protocol.";
      client connections.";
    reference
     "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)";
  }

  feature tls ssh-call-home {
    description
     "The tls ssh-call-home feature indicates that the NETCONF
      server supports the
      TLS transport protocol."; initiating a NETCONF over SSH call
      home connection to NETCONF clients.";
    reference
     "RFC 5539: YYYY: NETCONF over Transport Layer Security (TLS)"; Call Home and RESTCONF Call Home";
  }

  feature listen tls-listen {
    description
     "The listen tls-listen feature indicates that the NETCONF server
      supports opening a port to listen for incoming accept NETCONF over TLS
      client connections.";
    reference
     "RFC 6242: 5539: Using the NETCONF Protocol over Secure Shell (SSH)
      RFC 5539: NETCONF over Transport
                Layer Security (TLS)"; (TLS) with Mutual X.509
                Authentication";
  }

  feature call-home tls-call-home {
    description
     "The call-home tls-call-home feature indicates that the NETCONF
      server supports
      connecting initiating a NETCONF over TLS call
      home connection to the client"; NETCONF clients.";
    reference
     "RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
  }

  feature ssh-x509-certs {
    description
      "The ssh-x509-certs feature indicates that the NETCONF server
       supports RFC 6187";
    reference
      "RFC 6187: X.509v3 Certificates for Secure Shell Authentication";
  }
  // top-level container  (groupings below)
  container netconf-server {
    description
      "Top-level container for NETCONF server configuration.";

    uses session-options-container;
    uses listen-container;
    uses call-home-container;
    uses ssh-container;
    uses tls-container;

  }

  grouping session-options-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";
    container session-options

    container session-options {  // SHOULD WE REMOVE THIS ALTOGETHER?
      description
        "NETCONF session options, independent of transport
         or connection strategy.";
      leaf hello-timeout {
        type uint32 {
          range "0 | 10 .. 3600";
        } uint16;
        units "seconds";
        default '600'; 600;
        description
          "Specifies the maximum number of seconds that a session SSH/TLS
           connection may exist
           before the wait for a hello PDU is message to be received.
           A session connection will be dropped if no hello PDU message is
           received before this number of seconds elapses.  If this parameter is set
           to zero, then the server will wait forever for a hello message, and not drop any
           sessions stuck in 'hello-wait' state.

           Setting this parameter to zero may permit denial of
           service attacks, since only a limited
           message.";
      }
    }

    container listen {
      description
        "Configures listen behavior";
      if-feature "(ssh-listen or tls-listen)";
      leaf max-sessions {
        type uint16;
        default 0;
        description
          "Specifies the maximum number of concurrent sessions may
           that can be supported by the server."; active at one time.  The value 0 indicates
           that no artificial session limit should be used.";
      }
      leaf idle-timeout {
        type uint32 {
          range "0 | 10 .. 360000";
        } uint16;
        units "seconds";
        default '3600'; 3600; // one hour
        description
          "Specifies the maximum number of seconds that a NETCONF
           session may remain idle without issuing any RPC requests. idle. A NETCONF session will be dropped
           if it is idle for an interval longer than this number of
           seconds.  If this parameter is set to zero, then the server will never drop
           a session because it is idle.  Sessions that have a
           notification subscription active are never dropped.

           This mechanism is independent of keep-alives, as it regards
           activity occurring at the NETCONF protocol layer, whereas
           the keep-alive mechanism regards transport-level activity.";
      }
    }
  }

  grouping listen-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";
    container listen {
      description
        "Configures listen behavior";
      if-feature listen;
      leaf max-sessions {
        type uint16 {
          range "0 .. 1024";
        }
        default '0';
        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."; dropped.";
      }
      list endpoint {
        key name;
        description
          "List of endpoints to listen for NETCONF connections on.";
        leaf name {
          type string;
          description
            "An arbitrary name for the NETCONF listen endpoint.";
        }
        choice transport {
          mandatory true;
          description
            "Selects between SSH and TLS available transports.";
          case ssh {
            if-feature ssh; ssh-listen;
            container ssh {
              description
                "SSH-specific listening configuration for inbound
                 connections.";
              uses address-and-port-grouping {
                refine port {
                  default 830;
                }
              }
              uses host-keys-container; host-keys-grouping;
            }
          }
          case tls {
            if-feature tls; tls-listen;
            container tls {
              description
                "TLS-specific listening configuration for inbound
                 connections.";
              uses address-and-port-grouping {
                refine port {
                  default 6513;
                }
              }
              uses certificates-container;
            }
          }
        }
        uses keep-alives-container  {
          refine keep-alives/interval-secs {
            default 0; // disabled by default for listen connections certificates-grouping;
            }
          }
        }
      }
    }

  grouping call-home-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";

    container call-home {
      if-feature call-home; "(ssh-call-home or tls-call-home)";
      description
        "Configures call-home behavior";

      list application netconf-client {
        key name;
        description
          "List of NETCONF clients the NETCONF server is to initiate
           call-home connections to.";
        leaf name {
          type string;
          description
            "An arbitrary name for the remote NETCONF client.";
        }
        choice transport {
          mandatory true;
          description
            "Selects between available transports.";
          case ssh {
            if-feature ssh; ssh-call-home;
            container ssh {
              description
                "Specifies SSH-specific call-home transport
                 configuration.";
              uses endpoints-container {
                refine endpoints/endpoint/port {
                  default 7777;
                }
              }
              uses host-keys-container; host-keys-grouping;
            }
          }
          case tls {
            if-feature tls; tls-call-home;
            container tls {
              description
                "Specifies TLS-specific call-home transport
                 configuration.";
              uses endpoints-container {
                refine endpoints/endpoint/port {
                  default 8888;
                }
              }
              uses certificates-container; certificates-grouping;
            }
          }
        }
        container connection-type {
          description
           "Indicates the kind of connection to use.";
          choice connection-type {
            default persistent-connection;
            description
              "Selects between persistent and periodic connections."; available connection types.";
            case persistent-connection {
              container persistent {
                presence true;
                description
                 "Maintain a persistent connection to the NETCONF
                  client. If the connection goes down, immediately
                  start trying to reconnect to it, using the
                  reconnection strategy.

                  This connection type minimizes any NETCONF client
                  to NETCONF server data-transfer delay, albeit at
                  the expense of holding resources longer.";
                uses keep-alives-container  {
                  refine keep-alives/interval-secs
                leaf idle-timeout {
                  type uint32;
                  units "seconds";
                  default 15; 86400;  // 15 seconds for call-home sessions
                  }
                }
              }
            }
            case periodic-connection {
              container periodic { one day;
                  description
                 "Periodically connect to NETCONF client, using the
                  reconnection strategy, so the NETCONF client can
                  deliver pending messages to
                    "Specifies the maximum number of seconds that a
                     a NETCONF server.

                  For messages the session may remain idle. A NETCONF server wants to send to
                     session will be dropped if it is idle for an
                     interval longer than this number of seconds.
                     If set to zero, then the NETCONF client, the NETCONF server should
                  proactively connect to will never drop
                     a session because it is idle.  Sessions that
                     have a notification subscription active are
                     never dropped.";
                }
                container keep-alives {
                  description
                    "Configures the NETCONF client, if
                  not already, keep-alive policy, to send proactively
                     test the messages immediately."; aliveness of the SSH/TLS client.  An
                     unresponsive SSH/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 timeout-mins max-wait {
                    type uint8; uint16 {
                      range "1..max";
                    }
                    units minutes; seconds;
                    default 5; 30;
                    description
                   "The maximum
                     "Sets the amount of unconnected time the NETCONF
                    server will wait until establishing a connection to
                    the NETCONF client again. The NETCONF server MAY
                    establish a connection before this time in seconds after which
              if it has no data it needs to send has been received from the SSH/TLS
              client, a SSH/TLS-level message will be sent
                      to test the NETCONF client. Note:
                    this value differs from aliveness of the reconnection strategy's
                    interval-secs value."; SSH/TLS client.";
                  }
                  leaf linger-secs max-attempts {
                    type uint8;
                  units seconds;
                    default 30; 3;
                    description
                   "The amount of time
                     "Sets the NETCONF server should wait
                    after last receiving data from or sending data number of sequential keep-alive messages
              that can fail to obtain a response from the NETCONF client's endpoint SSH/TLS
              client before closing its
                    connection to it.  This assuming the SSH/TLS client is an optimization to
                    prevent unnecessary connections.";
                } no
              longer alive.";
                  }
                }
              }
            }
            case periodic-connection {
              container reconnect-strategy periodic {
                presence true;
                description
           "The reconnection strategy guides how a NETCONF server
            reconnects
                 "Periodically connect to an the NETCONF client, after losing a connection
            to it, even if due to a reboot. so that
                  the NETCONF client may deliver messages pending for
                  the NETCONF server.  The NETCONF client is expected
                  to close the connection when it is ready to release
                  it, thus starting the NETCONF server's timer until
                  next connection.";
                leaf idle-timeout {
                  type uint16;
                  units "seconds";
                  default 300; // five minutes
                  description
                    "Specifies the maximum number of seconds that a
                     a NETCONF session may remain idle. A NETCONF
                     session will be dropped if it is idle for an
                     interval longer than this number of seconds.
                     If set to zero, then the server will never drop
                     a session because it is idle.  Sessions that
                     have a notification subscription active are
                     never dropped.";
                }
                leaf reconnect_timeout {
                  type uint16 {
                    range "1..max";
                  }
                  units minutes;
                  default 60;
                  description
                   "The maximum amount of unconnected time the NETCONF
                    server will wait before establishing a connection
                    to the NETCONF client.   The NETCONF server may
                    initiate a connection before this time if desired
                    (e.g., to deliver a notification).";

                }
              }
            }
          }
        }
        container reconnect-strategy {
          description
           "The reconnection strategy guides how a NETCONF server
            reconnects to an NETCONF client, after losing a connection
            to it, even if due to a reboot.  The NETCONF server starts
            with the specified endpoint and tries to connect to it
            count-max times, waiting interval-secs between each
            connection attempt,
            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
                   the endpoint last connected to.  If no previous
                   connection has ever been established, then the
                   first endpoint configured is used.   NETCONF
                   servers SHOULD support this flag be able to remember the last
                   endpoint connected to across reboots.";
              }
            }
            default first-listed;
            description
             "Specifies which of the NETCONF client's endpoints the
              NETCONF server should start with when trying to connect
              to the NETCONF client.  If no previous connection has
              ever been established, last-connected defaults to
              the first endpoint listed."; client.";
          }
          leaf interval-secs max-attempts {
            type uint8;
            units seconds;
            default 5;
            description
             "Specifies the time delay between connection attempts
              to the same endpoint.  Note: this value differs from
              the periodic-connection's timeout-mins value.";
          }
          leaf count-max uint8 {
            type uint8;
              range "1..max";
            }
            default 3;
            description
             "Specifies the number times the NETCONF server tries to
              connect to a specific endpoint before moving on to the
              next endpoint in the list (round robin).";
          }
        }
      }

    }
  }

  grouping ssh-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";

    container ssh {
      description
        "Configures SSH properties not specific to the listen
         or call-home use-cases";
      if-feature ssh; "(ssh-listen or ssh-call-home)";
      container x509 {
        if-feature ssh-x509-certs;
        uses trusted-certs-grouping;
      }
    }
  }
  grouping tls-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";

    container tls {
      description
        "Configures TLS properties for authenticating clients.";
      if-feature tls; "(tls-listen or tls-call-home)";
      container client-auth {
        description
          "Container for TLS client authentication configuration.";
        uses trusted-certs-grouping;
        container cert-maps {
          uses x509c2n:cert-to-name;
          description
           "The cert-maps container is used by a NETCONF server to
            map the NETCONF client's presented X.509 certificate to a
            NETCONF username.  If no matching and valid cert-to-name
            list entry can be found, then the NETCONF server MUST
            close the connection, and MUST NOT accept NETCONF
            messages over it.";
          reference
            "RFC WWWW: NETCONF over TLS, Section 7";
        }
      }
    }
  }

  grouping trusted-certs-grouping {
    description
      "This grouping is used by both the ssh and tls containers.";
    container trusted-ca-certs {
      description
        "A list of Certificate Authority (CA) certificates that
         a NETCONF server can use to authenticate NETCONF client
         certificates.  A client's certificate is authenticated
         if there is a chain of trust to a configured trusted CA
         certificate.  The client certificate MAY be accompanied
         with additional certificates forming a chain of trust.
         certificates.";
      reference
        "RFC WWWW: NETCONF over TLS, Sections 5 and 7.
         RFC 4253: The client's certificate is authenticated if there is
         path-validation from any of the certificates it presents
         to a configured trust anchor."; Secure Shell (SSH) Transport Layer Protocol,
                   Section 8, #3.
         RFC 6187: X.509v3 Certificates for Secure Shell
                   Authentication.";
      leaf-list trusted-ca-cert {
        type binary;
        ordered-by system;
        nacm:default-deny-write;
        description
          "The binary certificate structure as specified by RFC
           5246, Section 7.4.6, i.e.,: opaque ASN.1Cert<1..2^24>;
          ";
        reference
          "RFC 5246: The Transport Layer Security (TLS)
                     Protocol Version 1.2";
      }
    }
    container trusted-client-certs {
      description
        "A list of client certificates that a NETCONF server can
         use to authenticate a NETCONF client's certificate.  A
         client's certificate is authenticated if it is an exact
         match to a configured trusted client certificates."; certificate.";
      leaf-list trusted-client-cert {
        type binary;
        ordered-by system;
        nacm:default-deny-write;
        description
          "The binary certificate structure, as
           specified by RFC 5246, Section 7.4.6, i.e.,:

             opaque ASN.1Cert<1..2^24>;

          ";
        reference
          "RFC 5246: The Transport Layer Security (TLS)
                     Protocol Version 1.2";
      }
    }
  }

  grouping host-keys-container host-keys-grouping {
    description
      "This grouping is used by both the listen and
       call-home containers";
    container host-keys {
      description
        "Parent container for the list of host-keys.";
      leaf-list host-key {
        type string;
        min-elements 1;
        ordered-by user;
        description
          "A user-ordered list of host-keys the SSH server
           considers when composing the list of server host
           key algorithms it will send to the client in its
           SSH_MSG_KEXINIT message.  The value of the string
           is the unique identifier for a host-key configured
           on the system.  How valid values are discovered is
           outside the scope of this module, but they are
           envisioned to be the keys for a list of host-keys
           provided by another YANG module";
        reference
          "RFC 4253: The SSH Transport Layer Protocol, Section 7";
      }
    }
  }

  grouping certificates-container certificates-grouping {
    description
      "This grouping is used by both the listen and
       call-home containers";
    container certificates {
      description
        "Parent container for the list of certificates.";
      leaf-list certificate {
        type string;
        min-elements 1;
        description
          "An unordered list of certificates the TLS server can pick
           from when sending its Server Certificate message.  The value
           of the string is the unique identifier for a certificate
           configured on the system.  How valid values are discovered
           is outside the scope of this module, but they are envisioned
           to be the keys for a list of certificates provided
           by another YANG module";
        reference
          "RFC 5246: The TLS Protocol, Section 7.4.2";
      }
    }
  }

  grouping address-and-port-grouping {
    description
      "This grouping is usd used by both the ssh and tls containers
       for listen configuration.";
    leaf address {
      type inet:ip-address;
      description
       "The IP address of the interface to listen on."; on. The NETCONF
        server will listen on all interfaces if no value is
        specified.";
    }
    leaf port {
      type inet:port-number;
      description
       "The local port number on this interface the NETCONF server
        listens on."; on.  The NETCONF server will use the IANA-assigned
        well-known port if no value is specified.";
    }
  }

  grouping endpoints-container {
    description
      "This grouping is used by both the ssh and tls containers
       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 NETCONF client.
           Defining more than one enables high-availability.";
        leaf name {
          type string;
          description
            "An arbitrary name for the endpoint to connect to."; this endpoint.";
        }
        leaf address {
          type inet:host;
          mandatory true;
          description
           "The hostname or IP address or hostname of the endpoint.  If a
            hostname is provided configured and the DNS resolves to resolution results
            in more than one IP address, the NETCONF server SHOULD try all of
            will process the ones it can based on how its networking stack is IP addresses as if they had been
            explicitly configured (e.g. v4, v6, dual-stack)."; in place of the hostname.";
        }
        leaf port {
          type inet:port-number;
          description
           "The IP port for this endpoint. The NETCONF server will
            use the IANA-assigned well-known port if not no value is
            specified.";
        }
      }
    }
  }

  grouping keep-alives-container {
    description
      "This grouping is use by both listen and call-home configurations.";
    container keep-alives {
      description
        "Configures the keep-alive policy, to proactively test the
         aliveness of the NETCONF client.";
      reference
        "RFC VVVV: NETCONF Server and

}

<CODE ENDS>

4.  The RESTCONF Server Configuration
         Models, Section 4";
      leaf interval-secs {
        type uint8;
        units seconds;
        description
         "Sets a timeout interval in seconds after which if no data
          has been received from the NETCONF client, a message will
          be sent to request a response from the NETCONF client.  A
          value of '0' indicates that no keep-alive messages should
          be sent.";
      }
      leaf count-max {
        type uint8;
        default 3;
        description
         "Sets the number of keep-alive messages that may be sent
          without receiving any data from the NETCONF client before
          assuming the NETCONF client is no longer alive.  If this
          threshold is reached, the transport-level connection will
          be disconnected, which will trigger the reconnection
          strategy).  The interval timer is reset after each
          transmission, thus an unresponsive NETCONF client will
          be dropped after approximately (count-max * interval-secs)
          seconds.";
      }
    }
  }
}

<CODE ENDS>

4.  The RESTCONF Server Configuration Model

4.1.  Overview

4.1.1.  The "listen" subtree  Tree Diagram

   module: ietf-restconf-server
      +--rw restconf-server
         +--rw listen {listen}? {tls-listen}?
         |  +--rw max-sessions?   uint16
         |  +--rw endpoint* [name]
         |     +--rw name    string
         |     +--rw (transport)
         |        +--:(tls)
         |           +--rw tls
         |              +--rw address?        inet:ip-address
         |              +--rw port?           inet:port-number
         |              +--rw certificates
         |                 +--rw certificate*   string
         +--rw keep-alives
                  +--rw interval-secs?   uint8
                  +--rw count-max?       uint8

   The above subtree illustrates how the ietf-restconf-server YANG
   module enables configuration for listening for remote connections, as
   described in [draft-ietf-netconf-restconf].  Feature statements are
   used to limit both if listening is supported at all as well as for
   which transports.  If listening for connections is supported, then
   the model enables configuring a list of listening endpoints, each
   configured with a user-specified name (the key field), the transport
   to use (i.e.  TLS), and the IP address and port to listen on.  The
   port field is optional, defaulting to the transport-specific port
   when not configured.  Please see the YANG module (Section 4.2) for a
   complete description of these configuration knobs.

4.1.2.  The "call-home" subtree
   module: ietf-restconf-server
      +--rw restconf-server
         +--rw call-home {call-home}? {tls-call-home}?
         |  +--rw application* restconf-client* [name]
         |     +--rw name                  string
         |     +--rw (transport)
         |     |  +--:(tls) {tls}?
         |     |     +--rw tls
         |     |        +--rw endpoints
         |     |        |  +--rw endpoint* [name]
         |     |        |     +--rw name       string
         |     |        |     +--rw address    inet:host
         |     |        |     +--rw port?      inet:port-number
         |     |        +--rw certificates
         |     |           +--rw certificate*   string
         |     +--rw connection-type
         |     |  +--rw (connection-type)?
         |     |     +--:(persistent-connection)
         |     |     |  +--rw persistent persistent!
         |     |     |     +--rw keep-alives
         |     |     |        +--rw interval-secs?   uint8 max-wait?       uint16
         |     |     |        +--rw count-max? max-attempts?   uint8
         |     |     +--:(periodic-connection)
         |        +--rw periodic     |        +--rw timeout-mins?   uint8 periodic!
         |     |           +--rw linger-secs?    uint8 reconnect-timeout?   uint16
         |     +--rw reconnect-strategy
         |        +--rw start-with?     enumeration
         |        +--rw interval-secs? max-attempts?   uint8
         +--rw count-max?       uint8

   The above subtree illustrates how the ietf-restconf-server YANG
   module enables configuration for call home, as described in
   [draft-ietf-netconf-call-home].  Feature statements are used to limit
   both if call-home is supported at all as well as for which
   transports, if it is.  If call-home is supported, then the model
   supports configuring a list of applications to connect to.  Each
   application is configured with a user-specified name (the key field),
   the transport to be used (i.e.  TLS), and a list of remote endpoints,
   each having a name, an IP address, and an optional port.
   Additionally, the configuration for each remote application indicates
   the connection-type (persistent vs. periodic) and associated
   parameters, as well as the reconnection strategy to use.  Please see
   the YANG module (Section 4.2) for a complete description of these
   configuration knobs.

4.1.3.  The "client-cert-auth" subtree

   module: ietf-restconf-server
      +--rw restconf-server
         +--rw client-cert-auth {client-cert-auth}?
            +--rw trusted-ca-certs
            |  +--rw trusted-ca-cert*   binary
            +--rw trusted-client-certs
            |  +--rw trusted-client-cert*   binary
            +--rw cert-maps
               +--rw cert-to-name* [id]
                  +--rw id             uint32
                  +--rw fingerprint    x509c2n:tls-fingerprint
                  +--rw map-type       identityref
                  +--rw name           string

4.2.  Example Usage

4.2.1.  Configuring TLS Transport

   The above subtree following example illustrates how the ietf-restconf-server YANG
   module enables configuration of client-certificate authentication.
   Specifically, this data-model provides 1) an ability to configure how
   client-certificates are authenticated and 2) how authenticated
   client-certificates are mapped to <get> response from a RESTCONF user names.  Please see
   the YANG module (Section 4.2)
   server that only supports TLS, both listening for incoming
   connections as well as calling home to a complete description of these
   configuration knobs.

4.2. single RESTCONF client
   having two endpoints.

<restconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-server">
  <listen>
    <endpoint>
      <name>primary-restconf-endpoint</name>
      <tls>
        <address>11.22.33.44</address>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </endpoint>
  </listen>
  <call-home>
    <restconf-client>
      <name>config-mgr</name>
      <tls>
        <endpoints>
          <endpoint>
            <name>east-data-center</name>
            <address>11.22.33.44</address>
          </endpoint>
          <endpoint>
            <name>west-data-center</name>
            <address>55.66.77.88</address>
          </endpoint>
        </endpoints>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </restconf-client>
  </call-home>
</restconf-server>

4.3.  YANG Module Model

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

<CODE BEGINS> file "ietf-restconf-server@2015-02-02.yang" "ietf-restconf-server@2015-07-06.yang"

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

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

  import ietf-netconf-acm {
    prefix nacm;                     // RFC 6536
    revision-date 2012-02-22;
  }
  import ietf-inet-types {           // RFC 6991
    prefix inet;
    revision-date 2013-07-15;
  }
  import ietf-x509-cert-to-name {    // RFC 7407
    prefix x509c2n;
    revision-date 2014-12-10;
  }

  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 VVVV; see
    the RFC itself for full legal notices.";

  revision "2015-02-02" "2015-07-06" {
    description
     "Initial version";
    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }

  // Features

  feature tls {
    description
     "The tls feature indicates that the server supports RESTCONF
      over the TLS transport protocol.";

    reference
     "RFC XXXX: RESTCONF Protocol";
  }

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

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

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

    uses listen-container;
    uses call-home-container;
    uses client-cert-auth-container;
  }

  grouping listen-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";

    container listen {
      description
        "Configures listen behavior";
      if-feature listen; tls-listen;
      leaf max-sessions {
        type uint16 {
          range "0 .. 1024";
        } uint16;
        default '0'; 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 {
            container tls {
              description
                "TLS-specific listening configuration for inbound
                 connections.";
              uses address-and-port-grouping {
                refine port
              leaf address {
                  default 443;
                }
              }
              uses certificates-container;
            }
          }
        }
        uses keep-alives-container  {
          refine keep-alives/interval-secs
                type inet:ip-address;
                description
                 "The IP address of the interface to listen on. The
                  RESTCONF server will listen on all interfaces if
                  no value is specified.";
              }
              leaf port {
                type inet:port-number;
                default 0; // disabled by default for 443;
                description
                 "The port number the RESTCONF server will listen connections on.";
              }
              uses certificates-grouping;
            }
          }
        }
      }
    }

  grouping call-home-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";

    container call-home {
      if-feature call-home; tls-call-home;
      description
        "Configures call-home behavior";
      list application 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 future transports augmented in.";
          case tls {
            if-feature tls;
            container tls {
              description
                "Specifies TLS-specific call-home transport
                 configuration.";
              uses endpoints-container
              container endpoints {
                refine endpoints/endpoint/port
                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.  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;
                    default 9999;
                    description
                     "The IP port for this endpoint. The RESTCONF
                      server will use the IANA-assigned well-known
                      port if no value is specified.";
                  }

                }
              }
              uses certificates-container; certificates-grouping;
            }
          }
        }
        container connection-type {
          description
           "Indicates the RESTCONF client's preference for how the
            RESTCONF server's connection is maintained.";
          choice connection-type {
            default persistent-connection;
            description
              "Selects between persistent and periodic connections."; 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.";
                uses keep-alives-container  {
                  refine keep-alives/interval-secs {
                    default 15; // 15 seconds for call-home sessions
                  }
                }
              }
            }
            case periodic-connection {

                container periodic keep-alives {
                  description
                 "Periodically connect
                    "Configures the keep-alive policy, to RESTCONF client, using proactively
                     test the
                  reconnection strategy, so aliveness of the RESTCONF TLS client.  An
                     unresponsive TLS client can
                  deliver pending messages to the will be dropped after
                     approximately (max-attempts * max-wait) seconds.";
                  reference
                    "RFC YYYY: NETCONF Call Home and RESTCONF server.

                  For messages Call Home,
                     Section 3.1, item S6";
                  leaf max-wait {
                    type uint16 {
                      range "1..max";
                    }
                    units seconds;
                    default 30;
                    description
                     "Sets the RESTCONF server wants 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 send
                      test the aliveness of the TLS client.";
                  }
                  leaf max-attempts {
                    type uint8;
                    default 3;
                    description
                     "Sets the 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.";
                  }
                }
              }
            }
            case periodic-connection {
              container periodic {
                presence true;
                description
                 "Periodically connect to the RESTCONF client, so that
                  the RESTCONF server should
                  proactively connect to client may deliver messages pending for
                  the RESTCONF client, if
                  not already, server.  The RESTCONF client is expected
                  to send close the messages immediately."; connection when it is ready to release
                  it, thus starting the RESTCONF server's timer until
                  next connection.";
                leaf timeout-mins reconnect-timeout {
                  type uint8; uint16 {
                    range "1..max";
                  }
                  units minutes;
                  default 5; 60;
                  description
                   "The maximum amount of unconnected time the RESTCONF
                    server will wait until establishing before re-establishing a connection
                    to the RESTCONF client again. client.  The RESTCONF server MAY
                    establish may
                    initiate a connection before this time if it has
                    data it needs to send to the RESTCONF client. Note:
                    this value differs from the reconnection strategy's
                    interval-secs value.";
                }
                leaf linger-secs {
                  type uint8;
                  units seconds;
                  default 30;
                  description
                   "The amount of time the RESTCONF server should wait
                    after last receiving data from or sending data to
                    the RESTCONF client's endpoint before closing its
                    connection to it.  This is an optimization desired
                    (e.g., to
                    prevent unnecessary connections."; deliver a notification).";
                }
              }
            }
          }
        }
        container reconnect-strategy {
          description
           "The reconnection strategy guides how a RESTCONF server
            reconnects to an RESTCONF client, after losing a connection
            to it, even if due to a reboot.  The RESTCONF server starts
            with the specified endpoint and tries to connect to it
            count-max times, waiting interval-secs between each
            connection attempt,
            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
                   the endpoint last connected to.  If no previous
                   connection has ever been established, then the
                   first endpoint configured is used.   RESTCONF
                   servers SHOULD support this flag 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.  If no previous connection has
              ever been established, last-connected defaults to
              the first endpoint listed."; client.";
          }
          leaf interval-secs max-attempts {
            type uint8;
            units seconds; uint8 {
              range "1..max";
            }
            default 5;
            description
             "Specifies the time delay between connection attempts
              to the same endpoint.  Note: this value differs from
              the periodic-connection's timeout-mins value.";
          }
          leaf count-max {
            type uint8;
            default 3; 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 client-cert-auth-container {
    description
      "This grouping is used only to help improve readability
       of the YANG module.";

    container client-cert-auth {
      if-feature client-cert-auth;
      description
        "Container for TLS client certificate authentication
         configuration.";
      container trusted-ca-certs {
        description
          "A list of Certificate Authority (CA) certificates that
           a NETCONF RESTCONF server can use to authenticate NETCONF client
           certificates.  A client's certificate is authenticated
           if there is a chain of trust to a configured trusted CA
           certificate.  The RESTCONF client certificate MAY be accompanied
           with additional certificates forming a chain of trust.
           The client's certificate is authenticated if there is
           path-validation from any of the certificates it presents
           to a configured trust anchor.";
           certificates.";
        reference
          "RFC XXXX: RESTCONF Protocol, Sections 2.3 and 2.5.";
        leaf-list trusted-ca-cert {
          type binary;
          ordered-by system;
          nacm:default-deny-write;
          description
            "The binary certificate structure as specified by RFC
             5246, Section 7.4.6, i.e.,: opaque ASN.1Cert<1..2^24>;
            ";
          reference
            "RFC 5246: The Transport Layer Security (TLS)
                       Protocol Version 1.2";
        }
      }
      container trusted-client-certs {
        description
          "A list of client certificates that a NETCONF RESTCONF server can
           use to authenticate a NETCONF RESTCONF client's certificate.  A
           client's certificate is authenticated if it is an exact
           match to a configured trusted client certificates."; certificate.";
        leaf-list trusted-client-cert {
          type binary;
          ordered-by system;
          nacm:default-deny-write;
          description
            "The binary certificate structure, as specified by RFC
             5246, Section 7.4.6, i.e.,: opaque ASN.1Cert<1..2^24>;
            ";
          reference
            "RFC 5246: The Transport Layer Security (TLS)
                       Protocol Version 1.2";
        }
      }
      container cert-maps {
        uses x509c2n:cert-to-name;
        description
         "The cert-maps container is used by a NETCONF RESTCONF server to
          map the NETCONF RESTCONF client's presented X.509 certificate to a
          NETCONF
          RESTCONF username.  If no matching and valid cert-to-name
          list entry can be found, then the NETCONF RESTCONF server MUST
          close the connection, and MUST NOT accept NETCONF RESTCONF
          messages over it.";
        reference
          "RFC XXXX: RESTCONF Protocol, Section 2.5";
      }
    }
  }

  grouping certificates-container certificates-grouping {
    description
      "This grouping is used by both the listen and
       call-home containers";
    container certificates {
      description
        "Parent container for the list of certificates.";
      leaf-list certificate {
        type string;
        min-elements 1;
        description
          "An unordered list of certificates the TLS server can pick
           from when sending its Server Certificate message.  The value
           of the string is the unique identifier for a certificate
           configured on the system.  How valid values are discovered
           is outside the scope of this module, but they are envisioned
           to be the keys for a list of certificates provided
           by another YANG module";
        reference
          "RFC 5246: The TLS Protocol, Section 7.4.2";
      }
    }
  }

  grouping address-and-port-grouping {
    description
      "This grouping is usd by both the ssh and tls containers
       for listen configuration.";
    leaf address {
      type inet:ip-address;
      description
       "The IP address

}

<CODE ENDS>

5.  Security Considerations

   There are a number of data nodes defined in the interface "ietf-netconf-server"
   YANG module which are readable and/or writable that may be considered
   sensitive or vulnerable in some network environments.  Write and read
   operations to listen on.";
    }
    leaf port {
      type inet:port-number;
      description
       "The local port number these data nodes can have a negative effect on this interface the RESTCONF server
        listens on.";
    }
  }

  grouping endpoints-container {
    description
      "This grouping network
   operations.  It is used by both thus important to control write and read access to
   these data nodes.  Below are the ssh data nodes and tls containers
       for call-home configurations."; their sensitivity/
   vulnerability.

   netconf-server/tls/client-auth/trusted-ca-certs:

   o  This 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 contains certificates that a NETCONF server is to
      use as trust anchors for the endpoint authenticating X.509-based client
      certificates.  Write access to connect to.";
        }
        leaf address {
          type inet:host;
          mandatory true;
          description
           "The hostname or IP address or hostname of the endpoint.
            If this node is protected using an
      nacm:default-deny-write statement.

   netconf-server/tls/client-auth/trusted-client-certs:

   o  This container contains certificates that a hostname NETCONF server is provided and DNS resolves to more than
            one IP address, the
      trust directly when authenticating X.509-based client
      certificates.  Write access to this node is protected using an
      nacm:default-deny-write statement.

   restconf-server/tls/client-auth/trusted-ca-certs:

   o  This container contains certificates that a RESTCONF server SHOULD try all of
            the ones it can based on how its networking stack is
            configured (e.g. v4, v6, dual-stack).";
        }
        leaf port {
          type inet:port-number;
          description
           "The IP port to
      use as trust anchors for authenticating X.509-based client
      certificates.  Write access to this endpoint. The node is protected using an
      nacm:default-deny-write statement.

   restconf-server/tls/client-auth/trusted-client-certs:

   o  This container contains certificates that a RESTCONF server will
            use the IANA-assigned well-known port if not specified.";
        }
      }
    }
  }

  grouping keep-alives-container {
    description
      "This grouping is use by both listen and call-home configurations.";
    container keep-alives {
      description
        "Configures the keep-alive policy, to proactively test
      trust directly when authenticating X.509-based client
      certificates.  Write access to this node is protected using an
      nacm:default-deny-write statement.

6.  IANA Considerations

   This document registers two URIs in the
         aliveness of IETF XML registry [RFC2119].
   Following the RESTCONF client.";
      reference
        "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
         Models, Section 4";
      leaf interval-secs {
        type uint8;
        units seconds;
        description
         "Sets a timeout interval format in seconds after which if no data
          has been received from the RESTCONF client, a message will
          be sent to request a response from the RESTCONF client.  A
          value of '0' indicates that no keep-alive messages should
          be sent.";
      }
      leaf count-max {
        type uint8;
        default 3;
        description
         "Sets [RFC3688], the number following registrations are
   requested:

      URI: urn:ietf:params:xml:ns:yang:ietf-netconf-server
      Registrant Contact: The NETCONF WG of keep-alive messages that may be sent
          without receiving any data from the RESTCONF client before
          assuming the RESTCONF client is no longer alive.  If this
          threshold is reached, the transport-level connection will
          be disconnected, which will trigger IETF.
      XML: N/A, the reconnection
          strategy).  The interval timer requested URI is reset after each
          transmission, thus an unresponsive RESTCONF client will
          be dropped after approximately (count-max * interval-secs)
          seconds.";
      }
    }
  }
}

<CODE ENDS>

5.  Implementation strategy for keep-alives

   One XML namespace.

      URI: urn:ietf:params:xml:ns:yang:ietf-restconf-server
      Registrant Contact: The NETCONF WG of the objectives listed above, Keep-alives for persistent
   connections Section 2.6.6, indicates a need for a "keep-alive"
   mechanism.  This section specifies how IETF.
      XML: N/A, the keep-alive mechanism requested URI is to
   be implemented for both an XML namespace.

   This document registers two YANG modules in the SSH and TLS transports.

   Both SSH and TLS have YANG Module Names
   registry [RFC6020].  Following the ability to support keep-alives securely.
   Using format in [RFC6020], the strategies listed below, the keep-alive messages
   following registrations are sent
   inside the encrypted tunnel and thus immune to attack.

5.1.  Keep-alives for SSH requested:

      name:         ietf-netconf-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-netconf-server
      prefix:       ncserver
      reference:    RFC VVVV

      name:         ietf-restconf-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-restconf-server
      prefix:       rcserver
      reference:    RFC VVVV

7.  Other Considerations

   The SSH keep-alive solution that YANG modules define herein do not themselves support virtual
   routing and forwarding (VRF).  It is expected to be used is ubiquitous
   in practice, though never being explicitly defined that external modules
   will augment in an RFC. VRF designations when needed.

8.  Acknowledgements

   The
   strategy used is to purposely send a malformed request message with a
   flag set to ensure a response.  More specifically, per section 4 of
   [RFC4253], either SSH peer can send a SSH_MSG_GLOBAL_REQUEST message
   with "want reply" set authors would like to '1' thank for following for lively discussions
   on list and that, if there is an error, will get
   back a SSH_MSG_REQUEST_FAILURE response.  Similarly, section 5 of
   [RFC4253] says that either SSH peer can send a
   SSH_MSG_CHANNEL_REQUEST message with "want reply" set to '1' 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, and
   that, if there is an error, will get back Bert
   Wijnen.

   Juergen Schoenwaelder and was partly funded by Flamingo, a SSH_MSG_CHANNEL_FAILURE
   response.

   To ensure that the request will fail, current implementations Network of this
   keep-alive strategy (e.g.  OpenSSH's `sshd` server) send an invalid
   "request name" or "request type", respectively.  Abiding to
   Excellence project (ICT-318488) supported by the
   extensibility guidelines specified in Section 6 of [RFC4251], these
   implementations European Commission
   under its Seventh Framework Programme.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use the "name@domain".  For instance, when configured in RFCs to send keep-alives, OpenSSH sends Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4253]  Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
              Transport Layer Protocol", RFC 4253, January 2006.

   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for the string
   "keepalive@openssh.com".  In order to remain compatible with existing
   implementations, this draft does not require a specific "request
   name" or "request type" string be used, implementations are free to
   pick values of their choosing.

5.2.  Keep-alives
              Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010.

   [RFC6187]  Igoe, K. and D. Stebila, "X.509v3 Certificates for TLS

   The TLS keep-alive solution that is expected to be used is defined in
   [RFC6520].  This solution allows both peers to advertise if they can
   receive heartbeat request messages from its peer.  For standard TLS
   connections, devices SHOULD advertise "peer_allowed_to_send", as per
   [RFC6520].  This advertisement is not a "MUST" in order to
   grandfather existing NETCONF/RESTCONF Secure
              Shell Authentication", RFC 6187, March 2011.

   [RFC6241]  Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
              Bierman, "Network Configuration Protocol (NETCONF)", RFC
              6241, June 2011.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over TLS implementations.  For Secure
              Shell (SSH)", RFC 6242, June 2011.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration
              Protocol (NETCONF) Access Control Model", RFC 6536, March
              2012.

   [RFC6991]  Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
              July 2013.

   [RFC7407]  Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for
              SNMP Configuration", RFC 7407, December 2014.

   [RFC7589]  Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS) with
              Mutual X.509 Authentication", RFC 7589, June 2015.

   [draft-ietf-netconf-call-home]
              Watsen, K., "NETCONF Call Home or and RESTCONF Call Home, the network management
   system MUST advertise "peer_allowed_to_send" per [RFC6520].  This is
   a "MUST" so as to ensure devices can depend on it always being there
   for call home connections, which is when keep-alives are needed the
   most.

6.  Security Considerations

   The YANG modules defined Home",
              draft-ieft-netconf-call-home-02 (work in this memo are designed progress), 2014.

   [draft-ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ieft-netconf-restconf-04 (work in
              progress), 2014.

9.2.  Informative References

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

Appendix A.  Alternative solution addressing Issue #49

   Option #4 for Issue #49 proposed to be accessed via
   the NETCONF protocol [RFC6241].  Authorization define configuration for access a
   keychain and on-going discussion proposed to specific
   portions of conceptual data create reusable
   groupings for SSH/TLS servers (referencing keys and operations within this module certificates held
   in the keychain) that the NETCONF/RESTCONF servers would uses.  This
   relationship is
   provided illustrated by the NETCONF access control model (NACM) [RFC6536].

   There are a number of data nodes defined in diagram below.

                     +-------------+
                     |ietf-keychain|
                     +-------------+
                         ^    ^
                         |    |
              <leafref>  |    |  <leafref>
            +------------+    +------------+
            |                              |
     +---------------+            +------------------+
     |ietf-ssh-server|            | ietf-tls-server  |
     +---------------+            +------------------+
       ^                               ^       ^
       | <uses>                        |       |
       |            <augments>         |       |
       |          +--------------------+       | <augments>
       |          |                            |
   +-------------------+         +--------------------+
   |ietf-netconf-server|         |ietf-restconf-server|
   +-------------------+         +--------------------+

   The following sections each of the "ietf-netconf-server" five YANG module which are readable and/or writable that may be considered
   sensitive or vulnerable in some network environments.  Write and read
   operations to these data nodes can have a negative effect on network
   operations.  It is thus important to control write and read access to
   these data nodes.  Below are the data nodes modules above.

A.1.  The Keychain Model

A.1.1.  Tree Diagram
module: ietf-keychain
   +--rw keychain
      +--rw private-keys
      |  +--rw private-key* [name]
      |     +--rw name            string
      |     +--ro algorithm?      enumeration
      |     +--ro key-length?     uint32
      |     +--ro public-key?     string
      |     +--rw certificates
      |        +--rw certificate* [name]
      |           +--rw name     string
      |           +--rw chain?   binary
      +--rw trusted-certificates* [name]
         +--rw name                   string
         +--rw trusted-certificate* [name]
            +--rw name           string
            +--rw certificate?   binary
rpcs:
   +---x generate-certificate-signing-request
   |  +---w input
   |  |  +---w private-key?   -> /keychain/private-keys/private-key/name
   |  |  +---w subject        binary
   |  |  +---w attributes?    binary
   |  +--ro output
   |     +--ro certificate-signing-request    binary
   +---x generate-private-key
      +---w input
         +---w name          string
         +---w algorithm     enumeration
         +---w key-length    uint32

A.1.2.  Example Usage

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

     <!-- private keys and their sensitivity/
   vulnerability.

   netconf-server/tls/client-auth/trusted-ca-certs:

   o  This container contains associated certificates that a NETCONF server is to
      use as trust anchors for authenticating X.509-based -->
     <private-keys>
       <private-key>
         <name>TPM key</name>
         <algorithm>rsa</algorithm>
         <key-length>2048</key-length>
         <public-key>
           cztvaWRoc2RmZ2tqaHNkZmdramRzZnZzZGtmam5idnNvO2RmanZvO3NkZ
           mJpdmhzZGZpbHVidjtvc2lkZmhidml1bHNkYmZ2aXNiZGZpYmhzZG87Zm
           JvO3NkZ25iO29pLmR6Zgo=
         </public-key>
         <certificates>
           <certificate>
             <name>IDevID Certificate</name>
             <chain>
               LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUNrekNDQWZ5Z
               0F3SUJBZ0lKQUpRT2t3bGpNK2pjTUEwR0NTcUdTSWIzRFFFQkJRVU
               FNRFF4Q3pBSkJnTlYKQkFZVEFsVlRNUkF3RGdZRFZRUUtFd2RsZUd
               GdGNHeGxNUk13RVFZRFZRUURFd3BEVWt3Z1NYTnpkV1Z5TUI0WApE
               diR1V4RXpBUkJnTlZCQU1UQ2tOU1RDQkpjM04xWlhJd2daOHdEUVl
               KS29aSWh2Y04KQVFFQkJRQURnWTBBTUlHSkFvR0JBTXVvZmFPNEV3
               El1QWMrQ1RsTkNmc0d6cEw1Um5ydXZsOFRIcUJTdGZQY3N0Zk1KT1
               FaNzlnNlNWVldsMldzaHE1bUViCkJNNitGNzdjbTAvU25FcFE0TnV
               bXBDT2YKQWdNQkFBR2pnYXd3Z2Frd0hRWURWUjBPQkJZRUZKY1o2W
               URiR0lPNDB4ajlPb3JtREdsRUNCVTFNR1FHQTFVZApJd1JkTUZ1QU
               ZKY1o2WURiR0lPNDB4ajlPb3JtREdsRUNCVTFvVGlrTmpBME1Rc3d
               mMKTUE0R0ExVWREd0VCL3dRRUF3SUNCREFTQmdOVkhSTUJBZjhFQ0
               RBR0FRSC9BZ0VBTUEwR0NTcUdTSWIzRFFFQgpCUVVBQTRHQkFMMmx
               rWmFGNWcyaGR6MVNhZnZPbnBneHA4eG00SHRhbStadHpLazFlS3Bx
               TXp4YXJCbFpDSHlLCklVbC9GVzRtV1RQS1VDeEtFTE40NEY2Zmk2d
               c4d0tSSElkYW1WL0pGTmlQS0VXSTF4K1I1aDZmazcrQzQ1QXg1RWV
               SWHgzZjdVM2xZTgotLS0tLUVORCBDRVJUSUZJQ0FURS0tLS0tCg==
             </chain>
           </certificate>
         </certificates>
       </private-key>
     </private-keys>

     <!-- trusted netconf/restconf client
      certificates.  Write access to this node is protected using an
      nacm:default-deny-write statement.

   netconf-server/tls/client-auth/trusted-client-certs:

   o  This container contains certificates that a NETCONF server is to
      trust directly when authenticating X.509-based client
      certificates.  Write access to this node is protected using an
      nacm:default-deny-write statement.

   restconf-server/tls/client-auth/trusted-ca-certs:

   o  This container contains -->
     <trusted-certificates>
       <name>Trusted certificates that a RESTCONF server is to
      use as for netconf/restconf client</name>
       <trusted-certificate>
         <name>George Jetson</name>
         <certificate>
           QmdOVkJBWVRBbFZUTVJBd0RnWURWUVFLRXdkbAplR0Z0Y0d4bE1RNHdEQ
           MkF6a3hqUDlVQWtHR0dvS1U1eUc1SVR0Wm0vK3B0R2FieXVDMjBRd2kvZ
           25PZnpZNEhONApXY0pTaUpZK2xtYWs3RTRORUZXZS9RdGp4NUlXZmdvN2
           RV0JCU2t2MXI2SFNHeUFUVkpwSmYyOWtXbUU0NEo5akJrQmdOVkhTTUVY
           VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
           UxNQWtHQTFVRUJoTUNWVk14RURBT0JnTlZCQW9UQjJWNApZVzF3YkdVeE
           V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
           NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
           Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
           WpiMjB2WlhoaGJYQnNaUzVqY215aU9LUTJNRFF4Q3pBSkJnTlZCQVlUQW
           xWVE1SQXdEZ1lEVlFRSwpFd2RsZUdGdGNHeGxNUk13RVFZRFZRUURFd3B
           EVWt3Z1NYTnpkV1Z5TUEwR0NTcUdTSWIzRFFFQkJRVUFBNEdCCkFFc3BK
           WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
           TQzcjFZSjk0M1FQLzV5eGUKN2QxMkxCV0dxUjUrbEl5N01YL21ka2M4al
           zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
           LS0tLUVORCBDRVJUSUZJQ0FURS0tLS0tCg==
         </certificate>

       </trusted-certificate>
       <trusted-certificate>
         <name>Fred Flinstone</name>
         <certificate>
           VlEVlFRREV3Vm9ZWEJ3ZVRDQm56QU5CZ2txaGtpRzl3MEJBUUVGQUFPQm
           pRQXdnWWtDCmdZRUE1RzRFSWZsS1p2bDlXTW44eUhyM2hObUFRaUhVUzV
           rRUpPQy9hSFA3eGJXQW1ra054ZStUa2hrZnBsL3UKbVhsTjhSZUd1ODhG
           NGcEk3UE90cnNFVjRwTUNBd0VBQWFPQ0FSSXdnZ0VPCk1CMEdBMVVkRGd
           VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
           V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
           NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
           Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
           WpiMjB2WlhoaGJYQnNaUzVqY215aU9LUTJNRFF4Q3pBSkJnTlZCQVlUQW
           xWVE1SQXdEZ1lEVlFRSwpFd2RsZUdGdGNHeGxNUk13RVFZRFZRUURFd3B
           EVWt3Z1NYTnpkV1Z5TUEwR0NTcUdTSWIzRFFFQkJRVUFBNEdCCkFFc3BK
           WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
           lLQllsdWpOcjFTMnRLR05EMUc2OVJpK2FWNGw2NTdZNCtadVJMZgpRYjk
           zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
           QWtUOCBDRVUUZJ0RUF==
         </certificate>
       </trusted-certificate>
     </trusted-certificates>

     <!-- trust anchors for authenticating X.509-based client
      certificates.  Write access to this node is protected using an
      nacm:default-deny-write statement.

   restconf-server/tls/client-auth/trusted-client-certs:

   o  This container contains certificates that a RESTCONF server is to
      trust directly when authenticating X.509-based client
      certificates.  Write access to this node is protected using an
      nacm:default-deny-write statement.

7.  IANA Considerations

   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-netconf-server
      Registrant Contact: The netconf/restconf clients -->
     <trusted-certificates>
       <name>Trust anchors for netconf/restconf clients</name>
       <trusted-certificate>
         <name>Example.com</name>
         <certificate>
           WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
           lLQllsdWpOcjFTMnRLR05EMUc2OVJpK2FWNGw2NTdZNCtadVJMZgpRYjk
           zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
           NGcEk3UE90cnNFVjRwTUNBd0VBQWFPQ0FSSXdnZ0VPCk1CMEdBMVVkRGd
           VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
           V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
           NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
           Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
           WpiMjB2WlhoaGJYQnNaUzVqY215aU9LUTJNRFF4Q3pBSkJnTlZCQVlUQW
           QmdOVkJBWVRBbFZUTVJBd0RnWURWUVFLRXdkbAplR0Z0Y0d4bE1RNHdEQ
           MkF6a3hqUDlVQWtHR0dvS1U1eUc1SVR0Wm0vK3B0R2FieXVDMjBRd2kvZ
           25PZnpZNEhONApXY0pTaUpZK2xtYWs3RTRORUZXZS9RdGp4NUlXZmdvN2
           RJSUJQFRStS0Cg==
         </certificate>
       </trusted-certificate>
     </trusted-certificates>

     <!-- trust anchors for random HTTPS servers on Internet -->
     <trusted-certificates>
       <name>Trust anchors for random HTTPS servers</name>
       <trusted-certificate>
         <name>Example.com</name>
         <certificate>
           NGcEk3UE90cnNFVjRwTUNBd0VBQWFPQ0FSSXdnZ0VPCk1CMEdBMVVkRGd
           VEJiZ0JTWEdlbUEKMnhpRHVOTVkvVHFLNWd4cFJBZ1ZOYUU0cERZd05ER
           V6QVJCZ05WQkFNVENrTlNUQ0JKYzNOMVpYS0NDUUNVRHBNSll6UG8zREF
           Z05WSFI4RVlqQmdNRjZnSXFBZ2hoNW9kSFJ3T2k4dlpYaGgKYlhCc1pTN
           QmdOVkJBWVRBbFZUTVJBd0RnWURWUVFLRXdkbAplR0Z0Y0d4bE1RNHdEQ
           MkF6a3hqUDlVQWtHR0dvS1U1eUc1SVR0Wm0vK3B0R2FieXVDMjBRd2kvZ
           NQmdOVkhSTUJBZjhFCkFqQUFNQTRHQTFVZER3RUIvd1FFQXdJSGdEQnBC
           WmdsK2gyTTg3QmtGMjhWbW1CdFFVaWc3OEgrRkYyRTFwdSt4ZVRJbVFFM
           lLQllsdWpOcjFTMnRLR05EMUc2OVJpK2FWNGw2NTdZNCtadVJMZgpRYjk
           zSFNwSDdwVXBCYnA4dmtNanFtZjJma3RqZHBxeFppUUtTbndWZTF2Zwot
           25PZnpZNEhONApXY0pTaUpZK2xtYWs3RTRORUZXZS9RdGp4NUlXZmdvN2
           WpiMjB2WlhoaGJYQnNaUzVqY215aU9L=
         </certificate>
       </trusted-certificate>
     </trusted-certificates>

   </keychain>

A.1.3.  YANG Model

 <CODE BEGINS> file "ietf-keychain@2015-07-06.yang"

 module ietf-keychain {
   yang-version 1.1;

   namespace "urn:ietf:params:xml:ns:yang:ietf-keychain";
   prefix "kc";

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

   contact
    "WG Web:   <http://tools.ietf.org/wg/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 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 defines a keychain to centralize management of
     security credentials.

     Copyright (c) 2014 IETF Trust and the IETF.
      XML: N/A, persons identified as
     authors of the requested URI is an XML namespace.

   This document registers two YANG modules code. All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the YANG Module Names
   registry [RFC6020].  Following license terms contained in, the format Simplified BSD
     License set forth in [RFC6020], the Section 4.c of the
   following registrations are requested:

      name:         ietf-netconf-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-netconf-server
      prefix:       ncserver
      reference:    RFC VVVV

      name:         ietf-restconf-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-restconf-server
      prefix:       rcserver
      reference:    RFC VVVV

8.  Other Considerations

   The IETF Trust's
     Legal Provisions Relating to IETF Documents
     (http://trustee.ietf.org/license-info).

     This version of this YANG modules define herein do not themselves support virtual
   routing and forwarding (VRF).  It module is expected that external modules
   will augment in VRF designations when needed.

9.  Acknowledgements

   The authors would like to thank for following part of RFC VVVV; see
     the RFC itself for lively discussions
   on list full legal notices.";

   revision "2015-07-06" {
     description
      "Initial version";
     reference
      "RFC VVVV: NETCONF Server 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, RESTCONF Server Configuration
                 Models";
   }

   container keychain {
     description
       "A list of private-keys and Bert
   Wijnen.

   Juergen Schoenwaelder their associated certificates, as
        well as lists of trusted certificates for client certificate
        authentication.  RPCs are provided to generate a new private
        key and was partly funded by Flamingo, to generate a Network certificate signing requests.";

     container private-keys {
       description
         "A list of
   Excellence project (ICT-318488) supported private key maintained by the European Commission
   under its Seventh Framework Programme.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words keychain.";
       list private-key {
         key name;
         description
           "A private key.";
         leaf name {
           type string;
           description
             "An arbitrary name for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4251]  Ylonen, T. and C. Lonvick, the private key.";
         }
         leaf algorithm {
           type enumeration {
             enum rsa { description "TBD"; }
             enum dsa { description "TBD"; }
             enum secp192r1 { description "TBD"; }
             enum sect163k1 { description "TBD"; }
             enum sect163r2 { description "TBD"; }
             enum secp224r1 { description "TBD"; }
             enum sect233k1 { description "TBD"; }
             enum sect233r1 { description "TBD"; }
             enum secp256r1 { description "TBD"; }
             enum sect283k1 { description "TBD"; }
             enum sect283r1 { description "TBD"; }
             enum secp384r1 { description "TBD"; }
             enum sect409k1 { description "TBD"; }
             enum sect409r1 { description "TBD"; }
             enum secp521r1 { description "TBD"; }
             enum sect571k1 { description "TBD"; }
             enum sect571r1 { description "TBD"; }
           }
           config false;
           description
             "The Secure Shell (SSH)
              Protocol Architecture", RFC 4251, January 2006.

   [RFC4253]  Ylonen, T. and C. Lonvick, algorithm used by the private key.";
         }
         leaf key-length {
           type uint32;
           config false;
           description
             "The Secure Shell (SSH)
              Transport Layer Protocol", RFC 4253, January 2006.

   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for key-length used by the
              Network Configuration Protocol (NETCONF)", RFC 6020,
              October 2010.

   [RFC6187]  Igoe, K. and D. Stebila, "X.509v3 Certificates private key.";
         }
         leaf public-key {
           type string;
           config false;
           description
             "The public-key matching the private key.";
         }
         container certificates {
           list certificate {
             key name;
             description
               "A certificate for this public key.";
             leaf name {
               type string;
               description
                 "An arbitrary name for Secure
              Shell Authentication", RFC 6187, March 2011.

   [RFC6241]  Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
              Bierman, "Network Configuration Protocol (NETCONF)", RFC
              6241, June 2011.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", certificate.";
             }
             leaf chain {
               type binary;
               description
                 "The certificate itself, as well as an ordered
                  sequence of intermediate certificates leading
                  to a trust anchor, as specified by RFC 6242, June 2011.

   [RFC6520]  Seggelmann, R., Tuexen, M., and M. Williams, "Transport
              Layer Security (TLS) and Datagram 5246,
                  Section 7.4.2.";
               reference
                 "RFC 5246: The Transport Layer Security
              (DTLS) Heartbeat Extension", RFC 6520, February 2012.

   [RFC6536]  Bierman, A. and M. Bjorklund, "Network Configuration (TLS)
                            Protocol (NETCONF) Access Control Model", RFC 6536, March
              2012.

   [RFC6991]  Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
              July 2013.

   [RFC7407]  Bjorklund, M. and J. Schoenwaelder, Version 1.2";
             }
           }
           description
             "A YANG Data Model list of certificates for
              SNMP Configuration", RFC 7407, December 2014.

   [draft-ietf-netconf-call-home]
              Watsen, K., "NETCONF Call Home this public key.";
         }
         action generate-certificate-signing-request {
           description
             "Generates a certificate signing request structure for
              the associated private key using the passed subject
              and RESTCONF Call Home",
              draft-ieft-netconf-call-home-02 (work attribute values.";
           input {
             leaf subject {
               type binary;
               mandatory true;
               description
                 "The 'subject' field in progress), 2014.

   [draft-ietf-netconf-restconf]
              Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", draft-ieft-netconf-restconf-04 (work the CertificationRequestInfo
                  defined in RFC 2986, Section 4.1.";
               reference
                 "RFC 2986: PKCS #10: Certification Request Syntax
                            Specification Version 1.7";
             }
             leaf attributes {
               type binary;
               description
                 "The 'attributes' field in
              progress), 2014.

   [draft-ietf-netconf-rfc5539bis]
              Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS)",
              draft-ietf-netconf-rfc5539bis-06 (work CertificationRequestInfo
                  defined in progress), 2014.

10.2.  Informative References

   [RFC3688]  Mealling, M., RFC 2986, Section 4.1.";
               reference
                 "RFC 2986: PKCS #10: Certification Request Syntax
                            Specification Version 1.7";
             }
           }
           output {
             leaf certificate-signing-request {
               type binary;
               mandatory true;
               description
                 "The IETF XML Registry", BCP 81, CertificationRequestInfo structure as specified
                  by RFC 3688,
              January 2004.

Appendix A.  Examples

A.1.  NETCONF Configuration 2986, Section 4.1.";
               reference
                 "RFC 2986: PKCS #10: Certification Request Syntax
                            Specification Version 1.7";
             }
           }
         }

       }
       action generate-private-key {
         description
           "Generates a private key using SSH Transport

   The following example illustrates the <get> response from specified algorithm and
            key length.";
         input {
           leaf name {
             type string;
             mandatory true;
             description
               "The name this private-key should have when listed in
                /keychain/private-keys/private-key.  As such, the
                passed value must not match any existing 'name' value.";
           }
           leaf algorithm {
             type enumeration {
               enum rsa { description "TBD"; }
               enum dsa { description "TBD"; }
               enum secp192r1 { description "TBD"; }
               enum sect163k1 { description "TBD"; }
               enum sect163r2 { description "TBD"; }
               enum secp224r1 { description "TBD"; }
               enum sect233k1 { description "TBD"; }
               enum sect233r1 { description "TBD"; }
               enum secp256r1 { description "TBD"; }
               enum sect283k1 { description "TBD"; }
               enum sect283r1 { description "TBD"; }
               enum secp384r1 { description "TBD"; }
               enum sect409k1 { description "TBD"; }
               enum sect409r1 { description "TBD"; }
               enum secp521r1 { description "TBD"; }
               enum sect571k1 { description "TBD"; }
               enum sect571r1 { description "TBD"; }
             }
             mandatory true;
             description
               "The algorithm to be used.";
           }
           leaf key-length {
             type uint32;
             mandatory true;
             description
               "The key length to be used.";
           }
         }
       }
     }
     list trusted-certificates {
       key name;
       description
         "A list of lists of trusted certificates.";
       leaf name {
         type string;
         description
           "An arbitrary name for this list of trusted certificates.";
       }
       list trusted-certificate {
         key name;
         description
           "A list of trusted certificates for a NETCONF specific use.";
         leaf name {
           type string;
           description
             "An arbitrary name for this trusted certificate.";
         }
         leaf certificate {
           type binary;
           description
             "The binary certificate structure as specified by RFC
              5246, Section 7.4.6, i.e.,: opaque ASN.1Cert<1..2^24>;
             ";
           reference
             "RFC 5246: The Transport Layer Security (TLS)
                        Protocol Version 1.2";
         }
       }
     }
   }

   rpc generate-certificate-signing-request {
     description
       "Generates a certificate signing request structure for
        the specified private key using the passed subject
        and attribute values.";
     input {
       leaf private-key {
         type leafref {
           path "/keychain/private-keys/private-key/name";
         }
         description
           "The private key to generate the certificate signing
            request for.";
       }
       leaf subject {
         type binary;
         mandatory true;
         description
           "The 'subject' field in the CertificationRequestInfo
            defined in RFC 2986, Section 4.1.";
         reference
           "RFC 2986: PKCS #10: Certification Request Syntax
                      Specification Version 1.7";
       }
       leaf attributes {
         type binary;
         description
           "The 'attributes' field in the CertificationRequestInfo
            defined in RFC 2986, Section 4.1.";
         reference
           "RFC 2986: PKCS #10: Certification Request Syntax
                      Specification Version 1.7";
       }
     }
     output {
       leaf certificate-signing-request {
         type binary;
         mandatory true;
         description
           "The CertificationRequestInfo structure as specified
            by RFC 2986, Section 4.1.";
         reference
           "RFC 2986: PKCS #10: Certification Request Syntax
                      Specification Version 1.7";
       }
     }
   }

   rpc generate-private-key {
     description
       "Generates a private key using the specified algorithm and
        key length.";
     input {
       leaf name {
         type string;
         mandatory true;
         description
           "The name this private-key should have when listed in
            /keychain/private-keys/private-key.  As such, the
            passed value must not match any existing 'name' value.";
       }
       leaf algorithm {
         type enumeration {
           enum rsa { description "TBD"; }
           enum dsa { description "TBD"; }
           enum secp192r1 { description "TBD"; }
           enum sect163k1 { description "TBD"; }
           enum sect163r2 { description "TBD"; }
           enum secp224r1 { description "TBD"; }
           enum sect233k1 { description "TBD"; }
           enum sect233r1 { description "TBD"; }
           enum secp256r1 { description "TBD"; }
           enum sect283k1 { description "TBD"; }
           enum sect283r1 { description "TBD"; }
           enum secp384r1 { description "TBD"; }
           enum sect409k1 { description "TBD"; }
           enum sect409r1 { description "TBD"; }
           enum secp521r1 { description "TBD"; }
           enum sect571k1 { description "TBD"; }
           enum sect571r1 { description "TBD"; }
         }
         mandatory true;
         description
           "The algorithm to be used.";
       }
       leaf key-length {
         type uint32;
         mandatory true;
         description
           "The key length to be used.";
       }
     }
   }
 }

 <CODE ENDS>

A.2.  The SSH Server Model

A.2.1.  Tree Diagram

   The following tree diagram is faked, as a module having only a
   grouping in it has no tree diagram.  However, for illustrative
   purposes, a container has been added as nothing more than a "uses"
   statement of the grouping.

module: ietf-ssh-server
   +--rw fake-ssh-server
      +--rw host-keys
      |  +--rw host-key* [name]
      |     +--rw name           string
      |     +--rw (type)?
      |        +--:(public-key)
      |        |  +--rw public-key?    -> /kc:keychain/private-keys/private-key/name
      |        +--:(certificate)
      |           +--rw certificate?   -> /kc:keychain/private-keys/private-key/certificates/certificate/name {ssh-x509-certs}?
      +--rw client-cert-auth {ssh-x509-certs}?
         +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
         +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name

A.2.2.  Example Usage

   <fake-ssh-server xmlns="urn:ietf:params:xml:ns:yang:ietf-ssh-server">
     <host-keys>
       <host-key>
         <name>IDevID</name>
         <certificate>
           IDevID Certificate
         </certificate>
       </host-key>
     </host-keys>
     </certificates>
     <client-cert-auth>
       <trusted-ca-certs>
         Trusted certificates for netconf/restconf clients
       </trusted-ca-certs>
       <trusted-client-certs>
         Trust anchors for netconf/restconf clients
       </trusted-client-certs>
     </client-cert-auth>
   </fake-ssh-server>

A.2.3.  YANG Model

<CODE BEGINS> file "ietf-ssh-server@2015-07-06.yang"

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

  namespace "urn:ietf:params:xml:ns:yang:ietf-ssh-server";
  prefix "ts";
  import ietf-keychain {
    prefix kc;                       // RFC VVVV
  }

  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 defines a reusable grouping for a SSH server that
    can be used as a basis for specific SSH server instances.

    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 VVVV; see
    the RFC itself for full legal notices.";

  revision "2015-07-06" {
    description
     "Initial version";
    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }

  // features
  feature ssh-x509-certs {
    description
      "The ssh-x509-certs feature indicates that the NETCONF server
       supports RFC 6187";
    reference
      "RFC 6187: X.509v3 Certificates for Secure Shell Authentication";
  }

  // grouping
  grouping ssh-server-grouping {
    description
      "A reusable grouping for a SSH server that can be used as a
       basis for specific SSH server instances.";

    container host-keys {
      description
        "The list of host-keys the SSH server will present when
         establishing a SSH connection.";
      list host-key {
        key name;
        min-elements 1;
        ordered-by user;
        description
          "An ordered list of hostkeys the SSH server advertises
           when sending its ??? message.";
        reference
          "RFC ????: ...";
        leaf name {
          type string;
          mandatory true;
          description
            "An arbitrary name for this host-key";
        }
        choice type {
          leaf public-key {
            type leafref {
              path "/kc:keychain/kc:private-keys/kc:private-key/kc:name";
            }
            description
              "The name of a private-key in the keychain.";
          }
          leaf certificate {
            if-feature ssh-x509-certs;
            type leafref {
              path "/kc:keychain/kc:private-keys/kc:private-key/kc:certificates/kc:certificate/kc:name";
            }
            description
              "The name of a certificate in the keychain.";
          }

        }
      }
    }

    container client-cert-auth {
      if-feature ssh-x509-certs;
      description
        "A reference to a list of trusted certificate authority (CA)
         certificates and a reference to a list of trusted client
         certificates.";
      leaf trusted-ca-certs {
        type leafref {
          path "/kc:keychain/kc:trusted-certificates/kc:name";
        }
        description
          "A reference to a list of certificate authority (CA)
           certificates used by the SSH server to authenticate
           SSH client certificates.";
      }

      leaf trusted-client-certs {
        type leafref {
          path "/kc:keychain/kc:trusted-certificates/kc:name";
        }
        description
          "A reference to a list of client certificates used by
           the SSH server to authenticate SSH client certificates.
           A clients certificate is authenticated if it is an
           exact match to a configured trusted client certificate.";
      }
    }
  }
}

<CODE ENDS>

A.3.  The TLS Server Model

A.3.1.  Tree Diagram

   The following tree diagram is faked, as a module having only a
   grouping in it has no tree diagram.  However, for illustrative
   purposes, a container has been added as nothing more than a "uses"
   statement of the grouping.

module: ietf-tls-server
   +--rw fake-tls-server
      +--rw certificates
      |  +--rw certificate* [name]
      |     +--rw name    -> /kc:keychain/private-keys/private-key/certificates/certificate/name
      +--rw client-auth
         +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
         +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name

A.3.2.  Example Usage

   <fake-tls-server xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-server">
     </certificates>
       <certificate>
         IDevID Certificate
       </certificate>
     </certificates>
     <client-auth>
       <trusted-ca-certs>
         Trusted certificates for netconf/restconf clients
       </trusted-ca-certs>
       <trusted-client-certs>
         Trust anchors for netconf/restconf clients
       </trusted-client-certs>
     </client-auth>
   </fake-tls-server>

A.3.3.  YANG Model

<CODE BEGINS> file "ietf-tls-server@2015-07-06.yang"

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

  namespace "urn:ietf:params:xml:ns:yang:ietf-tls-server";
  prefix "ts";

  import ietf-keychain {
    prefix kc;                       // RFC VVVV
  }

  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 defines a reusable grouping for a TLS server that
    can be used as a basis for specific TLS server instances.

    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 VVVV; see
    the RFC itself for full legal notices.";

  revision "2015-07-06" {
    description
     "Initial version";
    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }

  grouping tls-server-grouping {
    description
      "A reusable grouping for a TLS server that can be used as a
       basis for specific TLS server instances.";

    container certificates {
      description
        "The list of certificates the TLS server will present when
         establishing a TLS connection.";
      list certificate {
        key name;
        min-elements 1;
        description
          "An unordered list of certificates the TLS server can pick
           from when sending its Server Certificate message.";
        reference
          "RFC 5246: The TLS Protocol, Section 7.4.2";
        leaf name {
          type leafref {
            path "/kc:keychain/kc:private-keys/kc:private-key/kc:certificates/kc:certificate/kc:name";
          }
          description
            "The name of the certificate in the keychain.";
        }
      }
    }

    container client-auth {
      description
        "A reference to a list of trusted certificate authority (CA)
         certificates and a reference to a list of trusted client
         certificates.";
      leaf trusted-ca-certs {
        type leafref {
          path "/kc:keychain/kc:trusted-certificates/kc:name";
        }
        description
          "A reference to a list of certificate authority (CA)
           certificates used by the TLS server to authenticate
           TLS client certificates.";
      }

      leaf trusted-client-certs {
        type leafref {
          path "/kc:keychain/kc:trusted-certificates/kc:name";
        }
        description
          "A reference to a list of client certificates used by
           the TLS server to authenticate TLS client certificates.
           A clients certificate is authenticated if it is an
           exact match to a configured trusted client certificate.";
      }
    }
  }
}
<CODE ENDS>

A.4.  The NETCONF Server Model

A.4.1.  Tree Diagram

module: ietf-netconf-server-new
   +--rw netconf-server
      +--rw session-options
      |  +--rw hello-timeout?   uint16
      +--rw listen {(ssh-listen or tls-listen)}?
      |  +--rw max-sessions?   uint16
      |  +--rw idle-timeout?   uint16
      |  +--rw endpoint* [name]
      |     +--rw name    string
      |     +--rw (transport)
      |        +--:(ssh) {ssh-listen}?
      |        |  +--rw ssh
      |        |     +--rw address?            inet:ip-address
      |        |     +--rw port?               inet:port-number
      |        |     +--rw host-keys
      |        |     |  +--rw host-key* [name]
      |        |     |     +--rw name           string
      |        |     |     +--rw (type)?
      |        |     |        +--:(public-key)
      |        |     |        |  +--rw public-key?    -> /kc:keychain/private-keys/private-key/name
      |        |     |        +--:(certificate)
      |        |     |           +--rw certificate?   -> /kc:keychain/private-keys/private-key/certificates/certificate/name {ssh-x509-certs}?
      |        |     +--rw client-cert-auth {ssh-x509-certs}?
      |        |        +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
      |        |        +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name
      |        +--:(tls) {tls-listen}?
      |           +--rw tls
      |              +--rw address?        inet:ip-address
      |              +--rw port?           inet:port-number
      |              +--rw certificates
      |              |  +--rw certificate* [name]
      |              |     +--rw name    -> /kc:keychain/private-keys/private-key/certificates/certificate/name
      |              +--rw client-auth
      |                 +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
      |                 +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name
      |                 +--rw cert-maps
      |                    +--rw cert-to-name* [id]
      |                       +--rw id             uint32
      |                       +--rw fingerprint    x509c2n:tls-fingerprint
      |                       +--rw map-type       identityref
      |                       +--rw name           string
      +--rw call-home {(ssh-call-home or tls-call-home)}?
         +--rw netconf-client* [name]
            +--rw name                  string
            +--rw (transport)
            |  +--:(ssh) {ssh-call-home}?
            |  |  +--rw ssh
            |  |     +--rw endpoints
            |  |     |  +--rw endpoint* [name]
            |  |     |     +--rw name       string
            |  |     |     +--rw address    inet:host
            |  |     |     +--rw port?      inet:port-number
            |  |     +--rw host-keys
            |  |     |  +--rw host-key* [name]
            |  |     |     +--rw name           string
            |  |     |     +--rw (type)?
            |  |     |        +--:(public-key)
            |  |     |        |  +--rw public-key?    -> /kc:keychain/private-keys/private-key/name
            |  |     |        +--:(certificate)
            |  |     |           +--rw certificate?   -> /kc:keychain/private-keys/private-key/certificates/certificate/name {ssh-x509-certs}?
            |  |     +--rw client-cert-auth {ssh-x509-certs}?
            |  |        +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
            |  |        +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name
            |  +--:(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    -> /kc:keychain/private-keys/private-key/certificates/certificate/name
            |        +--rw client-auth
            |           +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
            |           +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name
            |           +--rw cert-maps
            |              +--rw cert-to-name* [id]
            |                 +--rw id             uint32
            |                 +--rw fingerprint    x509c2n:tls-fingerprint
            |                 +--rw map-type       identityref
            |                 +--rw name           string
            +--rw connection-type
            |  +--rw (connection-type)?
            |     +--:(persistent-connection)
            |     |  +--rw persistent!
            |     |     +--rw idle-timeout?   uint32
            |     |     +--rw keep-alives
            |     |        +--rw max-wait?       uint16
            |     |        +--rw max-attempts?   uint8
            |     +--:(periodic-connection)
            |        +--rw periodic!
            |           +--rw idle-timeout?        uint16
            |           +--rw reconnect_timeout?   uint16
            +--rw reconnect-strategy
               +--rw start-with?     enumeration
               +--rw max-attempts?   uint8

A.4.2.  Example Usage

   Configuring an SSH Server

<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
  <listen>
    <endpoint>
      <name>netconf/ssh</name>
      <ssh>
        <address>11.22.33.44</address>
        <host-keys>
          <host-key>
            <public-key>my-rsa-key</public-key>
          </host-key>
          <host-key>
            <certificate>TPM key</certificate>
          </host-key>
        </host-keys>
        <client-cert-auth>
          <trusted-ca-certs>
            Trusted netconf/restconf client certificates
          </trusted-ca-certs>
          <trusted-client-certs>
            Trust anchors for netconf/restconf clients
          </trusted-client-certs>
        </client-cert-auth>
      </ssh>
    </endpoint>
  </listen>
  <call-home>
    <netconf-client>
      <name>config-mgr</name>
      <ssh>
        <endpoints>
          <endpoint>
            <name>east-data-center</name>
            <address>11.22.33.44</address>
          </endpoint>
          <endpoint>
            <name>west-data-center</name>
            <address>55.66.77.88</address>
          </endpoint>
        </endpoints>
        <host-keys>
          <host-key>
            <certificate>TPM key</certificate>
          </host-key>
        </host-keys>
        <client-cert-auth>
          <trusted-ca-certs>
            Trusted netconf/restconf client certificates
          </trusted-ca-certs>
          <trusted-client-certs>
            Trust anchors for netconf/restconf clients
          </trusted-client-certs>
        </client-cert-auth>
      </ssh>
    </netconf-client>
  </call-home>
</netconf-server>

   Configuring a TLS Server

<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server"
     xmlns:x509c2n="urn:ietf:params:xml:ns:yang:ietf-x509-cert-to-name">
  <listen>
    <endpoint>
      <name>netconf/tls</name>
      <tls>
        <address>11.22.33.44</address>
        <certificates>
          <certificate>IDevID Certificate</certificate>
        </certificates>
        <client-auth>
          <trusted-ca-certs>
            Trusted netconf/restconf client certificates
          </trusted-ca-certs>
          <trusted-client-certs>
            Trust anchors for netconf/restconf clients
          </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>
            </cert-to-name>
          </cert-maps>
        </client-auth>
      </tls>
    </endpoint>
  </listen>
  <call-home>
    <netconf-client>
      <name>config-mgr</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>IDevID Certificate</certificate>
        </certificates>
      </tls>
    </netconf-client>
  </call-home>
</netconf-server>

A.4.3.  YANG Model

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

<CODE BEGINS> file "ietf-netconf-server-new@2015-07-06.yang"

module ietf-netconf-server-new {
  yang-version 1.1;

  namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-server-new";
  prefix "ncserver";

  import ietf-inet-types {           // RFC 6991
    prefix inet;
  }
  import ietf-x509-cert-to-name {    // RFC 7407
    prefix x509c2n;
  }
  import ietf-ssh-server {           // RFC VVVV
    prefix ss;
  }
  import ietf-tls-server {           // RFC VVVV
    prefix ts;
  }

  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 NETCONF 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 VVVV; see
    the RFC itself for full legal notices.";

  revision "2015-07-06" {
    description
     "Initial version";

    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }

  // Features

  feature ssh-listen {
    description
     "The ssh-listen feature indicates that the NETCONF server
      supports opening a port to accept NETCONF over SSH
      client connections.";
    reference
     "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)";
  }

  feature ssh-call-home {
    description
     "The ssh-call-home feature indicates that the NETCONF
      server supports initiating a NETCONF over SSH call
      home connection to NETCONF clients.";
    reference
     "RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
  }

  feature tls-listen {
    description
     "The tls-listen feature indicates that the NETCONF server
      supports opening a port to accept NETCONF over TLS
      client connections.";
    reference
     "RFC 5539: Using the NETCONF Protocol over Transport
                Layer Security (TLS) with Mutual X.509
                Authentication";
  }

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

  feature ssh-x509-certs {
    description
      "The ssh-x509-certs feature indicates that the NETCONF server
       supports RFC 6187";
    reference
      "RFC 6187: X.509v3 Certificates for Secure Shell Authentication";
  }

  // top-level container  (groupings below)
  container netconf-server {
    description
      "Top-level container for NETCONF server configuration.";

    container session-options {  // SHOULD WE REMOVE THIS ALTOGETHER?
      description
        "NETCONF session options, independent of transport
         or connection strategy.";
      leaf hello-timeout {
        type uint16;
        units "seconds";
        default 600;
        description
          "Specifies the maximum number of seconds that a SSH/TLS
           connection may wait for a hello message to be received.
           A connection will be dropped if no hello message is
           received before this number of seconds elapses.  If set
           to zero, then the server will wait forever for a hello
           message.";
      }
    }

    container listen {
      description
        "Configures listen behavior";
      if-feature "(ssh-listen or tls-listen)";
      leaf max-sessions {
        type uint16;
        default 0;
        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.";
      }
      leaf idle-timeout {
        type uint16;
        units "seconds";
        default 3600; // one hour
        description
          "Specifies the maximum number of seconds that a NETCONF
           session may remain idle. A NETCONF session will be dropped
           if it is idle for an interval longer than this number of
           seconds.  If set to zero, then the server will never drop
           a session because it is idle.  Sessions that have a
           notification subscription active are never dropped.";
      }
      list endpoint {
        key name;
        description
          "List of endpoints to listen for NETCONF connections on.";
        leaf name {
          type string;
          description
            "An arbitrary name for the NETCONF listen endpoint.";
        }
        choice transport {
          mandatory true;
          description
            "Selects between available transports.";
          case ssh {
            if-feature ssh-listen;
            container ssh {
              description
                "SSH-specific listening configuration for inbound
                 connections.";
              uses address-and-port-grouping {
                refine port {
                  default 830;
                }
              }
              uses ss:ssh-server-grouping;
            }
          }
          case tls {
            if-feature tls-listen;
            container tls {
              description
                "TLS-specific listening configuration for inbound
                 connections.";
              uses address-and-port-grouping {
                refine port {
                  default 6513;
                }
              }
              uses tls-server-grouping;
            }
          }
        }

      }
    }

    container call-home {
      if-feature "(ssh-call-home or tls-call-home)";
      description
        "Configures call-home behavior";
      list netconf-client {
        key name;
        description
          "List of NETCONF clients the NETCONF server is to initiate
           call-home connections to.";
        leaf name {
          type string;
          description
            "An arbitrary name for the remote NETCONF client.";
        }
        choice transport {
          mandatory true;
          description
            "Selects between available transports.";
          case ssh {
            if-feature ssh-call-home;
            container ssh {
              description
                "Specifies SSH-specific call-home transport
                 configuration.";
              uses endpoints-container {
                refine endpoints/endpoint/port {
                  default 7777;
                }
              }
              uses ss:ssh-server-grouping;
            }
          }
          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 8888;
                }
              }
              uses tls-server-grouping;
            }

          }
        }
        container connection-type {
          description
           "Indicates the kind of connection to use.";
          choice connection-type {
            description
              "Selects between available connection types.";
            case persistent-connection {
              container persistent {
                presence true;
                description
                 "Maintain a persistent connection to the NETCONF
                  client. If the connection goes down, immediately
                  start trying to reconnect to it, using the
                  reconnection strategy.

                  This connection type minimizes any NETCONF client
                  to NETCONF server data-transfer delay, albeit at
                  the expense of holding resources longer.";
                leaf idle-timeout {
                  type uint32;
                  units "seconds";
                  default 86400;  // one day;
                  description
                    "Specifies the maximum number of seconds that a
                     a NETCONF session may remain idle. A NETCONF
                     session will be dropped if it is idle for an
                     interval longer than this number of seconds.
                     If set to zero, then the server will never drop
                     a session because it is idle.  Sessions that
                     have a notification subscription active are
                     never dropped.";
                }
                container keep-alives {
                  description
                    "Configures the keep-alive policy, to proactively
                     test the aliveness of the SSH/TLS client.  An
                     unresponsive SSH/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 SSH/TLS
              client, a SSH/TLS-level message will be sent
                      to test the aliveness of the SSH/TLS client.";
                  }
                  leaf max-attempts {
                    type uint8;
                    default 3;
                    description
                     "Sets the number of sequential keep-alive messages
              that can fail to obtain a response from the SSH/TLS
              client before assuming the SSH/TLS client is no
              longer alive.";
                  }
                }
              }
            }
            case periodic-connection {
              container periodic {
                presence true;
                description
                 "Periodically connect to the NETCONF client, so that
                  the NETCONF client may deliver messages pending for
                  the NETCONF server.  The NETCONF client is expected
                  to close the connection when it is ready to release
                  it, thus starting the NETCONF server's timer until
                  next connection.";
                leaf idle-timeout {
                  type uint16;
                  units "seconds";
                  default 300; // five minutes
                  description
                    "Specifies the maximum number of seconds that a
                     a NETCONF session may remain idle. A NETCONF
                     session will be dropped if it is idle for an
                     interval longer than this number of seconds.
                     If set to zero, then the server will never drop
                     a session because it is idle.  Sessions that
                     have a notification subscription active are
                     never dropped.";
                }
                leaf reconnect_timeout {
                  type uint16 {
                    range "1..max";
                  }
                  units minutes;
                  default 60;
                  description
                   "The maximum amount of unconnected time the NETCONF
                    server will wait before re-establishing a connection
                    to the NETCONF client.  The NETCONF server may
                    initiate a connection before this time if desired
                    (e.g., to deliver a notification).";
                }
              }
            }
          }
        }
        container reconnect-strategy {
          description
           "The reconnection strategy guides how a NETCONF server
            reconnects to an NETCONF client, after losing a connection
            to it, even if due to a reboot.  The NETCONF 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
                   the endpoint last connected to.  If no previous
                   connection has ever been established, then the
                   first endpoint configured is used.   NETCONF
                   servers SHOULD be able to remember the last
                   endpoint connected to across reboots.";
              }
            }
            default first-listed;
            description
             "Specifies which of the NETCONF client's endpoints the
              NETCONF server should start with when trying to connect
              to the NETCONF client.";
          }
          leaf max-attempts {
            type uint8 {
              range "1..max";
            }
            default 3;
            description
             "Specifies the number times the NETCONF server tries to
              connect to a specific endpoint before moving on to the
              next endpoint in the list (round robin).";
          }
        }
      }
    }
  }

  grouping tls-server-grouping {
    description
      "An augmentation of tls-server-grouping, as defined in the
       ietf-tls-server module, to add in cert-maps.";
    uses ts:tls-server-grouping {
      augment "client-auth" {
        container cert-maps {
          uses x509c2n:cert-to-name;
          description
           "The cert-maps container is used by a NETCONF server to
            map the NETCONF client's presented X.509 certificate to a
            NETCONF username.  If no matching and valid cert-to-name
            list entry can be found, then the NETCONF server MUST
            close the connection, and MUST NOT accept NETCONF
            messages over it.";
          reference
            "RFC WWWW: NETCONF over TLS, Section 7";
        }
      }
    }
  }

  grouping address-and-port-grouping {
    description
      "This grouping is used by both the ssh and tls containers
       for listen configuration.";
    leaf address {
      type inet:ip-address;
      description
       "The IP address of the interface to listen on. The NETCONF
        server will listen on all interfaces if no value is
        specified.";
    }
    leaf port {
      type inet:port-number;
      description
       "The local port number on this interface the NETCONF server
        listens on.  The NETCONF server will use the IANA-assigned
        well-known port if no value is specified.";
    }
  }

  grouping endpoints-container {
    description
      "This grouping is used by both the ssh and tls containers
       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 NETCONF 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 NETCONF 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 NETCONF server will
            use the IANA-assigned well-known port if no value is
            specified.";
        }
      }
    }
  }

}
<CODE ENDS>

A.5.  The RESTCONF Server Model

A.5.1.  Tree Diagram

module: ietf-restconf-server-new
   +--rw restconf-server
      +--rw listen {tls-listen}?
      |  +--rw max-sessions?   uint16
      |  +--rw endpoint* [name]
      |     +--rw name    string
      |     +--rw (transport)
      |        +--:(tls)
      |           +--rw tls
      |              +--rw address?        inet:ip-address
      |              +--rw port?           inet:port-number
      |              +--rw certificates
      |              |  +--rw certificate* [name]
      |              |     +--rw name    -> /kc:keychain/private-keys/private-key/certificates/certificate/name
      |              +--rw client-auth
      |                 +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
      |                 +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name
      |                 +--rw cert-maps
      |                    +--rw cert-to-name* [id]
      |                       +--rw id             uint32
      |                       +--rw fingerprint    x509c2n:tls-fingerprint
      |                       +--rw map-type       identityref
      |                       +--rw name           string
      +--rw call-home {tls-call-home}?
         +--rw restconf-client* [name]
            +--rw name                  string
            +--rw (transport)
            |  +--:(tls)
            |     +--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    -> /kc:keychain/private-keys/private-key/certificates/certificate/name
            |        +--rw client-auth
            |           +--rw trusted-ca-certs?       -> /kc:keychain/trusted-certificates/name
            |           +--rw trusted-client-certs?   -> /kc:keychain/trusted-certificates/name
            |           +--rw cert-maps
            |              +--rw cert-to-name* [id]
            |                 +--rw id             uint32
            |                 +--rw fingerprint    x509c2n:tls-fingerprint
            |                 +--rw map-type       identityref
            |                 +--rw name           string
            +--rw connection-type
            |  +--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

A.5.2.  Example Usage

   TBD

A.5.3.  YANG Model

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

<CODE BEGINS> file "ietf-restconf-server-new@2015-07-06.yang"

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

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

  import ietf-netconf-acm {
    prefix nacm;                     // RFC 6536
  }
  import ietf-inet-types {           // RFC 6991
    prefix inet;
  }
  import ietf-x509-cert-to-name {    // RFC 7407
    prefix x509c2n;
  }
  import ietf-tls-server {           // RFC VVVV
    prefix ts;
  }
  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 VVVV; see
    the RFC itself for full legal notices.";

  revision "2015-07-06" {
    description
     "Initial version";
    reference
     "RFC VVVV: NETCONF Server and RESTCONF Server Configuration
                Models";
  }

  // Features

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

  feature tls-call-home {
    description
     "The 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";
  }

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

    container listen {
      description
        "Configures listen behavior";
      if-feature tls-listen;
      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 {
            container tls {
              description
                "TLS-specific listening configuration for inbound
                 connections.";
              leaf address {
                type inet:ip-address;
                description
                 "The IP address of the interface to listen on. The
                  RESTCONF server will listen on all interfaces if
                  no value is specified.";
              }
              leaf port {
                type inet:port-number;
                default 443;
                description
                 "The port number the RESTCONF server will listen on.";
              }
              uses tls-server-grouping;
            }
          }
        }
      }
    }

    container call-home {
      if-feature tls-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 {
            container tls {
              description
                "Specifies TLS-specific call-home transport
                 configuration.";
              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.  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;
                    default 9999;
                    description
                     "The IP port for this endpoint. The RESTCONF
                      server will use the IANA-assigned well-known
                      port if no value is specified.";
                  }
                }
              }
              uses tls-server-grouping;
            }
          }
        }
        container connection-type {
          description
           "Indicates the RESTCONF client's preference for how the
            RESTCONF server's connection is maintained.";
          choice connection-type {
            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 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.";
                  }
                }

              }
            }
            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 RESTCONF client is expected
                  to close the connection when it is ready to release
                  it, thus starting the RESTCONF server's timer until
                  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 before this time if desired
                    (e.g., to deliver a notification).";
                }
              }
            }
          }
        }
        container reconnect-strategy {
          description
           "The reconnection strategy guides how a RESTCONF server
            reconnects to an RESTCONF client, after losing a connection
            to it, 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
                   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 that only supports SSH, both listening for incoming
   connections as well as calling home should start with when trying to connect
              to a single application having
   two endpoints.

<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
  <session-options>
    <hello-timeout>600</hello-timeout>
    <idle-timeout>3600</idle-timeout>
  </session-options>
  <listen>
    <endpoint>
      <name>foo bar</name>
      <ssh>
        <address>11.22.33.44</address>
        <host-keys>
          <host-key>my-rsa-key</host-key>
          <host-key>my-dss-key</host-key>
        </host-keys>
      </ssh>
    </endpoint>
  </listen>
  <call-home>
    <application>
      <name>config-mgr</name>
      <ssh>
        <endpoints>
          <endpoint>
            <name>east-data-center</name>
            <address>11.22.33.44</address>
          </endpoint>
          <endpoint>
            <name>west-data-center</name>
            <address>55.66.77.88</address>
          </endpoint>
        </endpoints>
        <host-keys>
          <host-key>my-call-home-x509-key</host-key>
        </host-keys>
      </ssh>
    </application>
  </call-home>
  <ssh>
    <x509>
      <trusted-ca-certs>
        <trusted-ca-cert>
          QW4gRWFzdGVyIGVnZywgZm9yIHRob3NlIHdobyBtaWdodCBsb29rICA6KQo=
        </trusted-ca-cert>
      </trusted-ca-certs>
      <trusted-client-certs>
        <trusted-client-cert>
          SSBhbSB0aGUgZWdnIG1hbiwgdGhleSBhcmUgdGhlIGVnZyBtZW4uCg==
        </trusted-client-cert>
        <trusted-client-cert>
          SSBhbSB0aGUgd2FscnVzLCBnb28gZ29vIGcnam9vYi4K
        </trusted-client-cert>
      </trusted-client-certs>
    </x509>
  </ssh>
</netconf-server>

A.2.  NETCONF Configuration using TLS Transport

   The following example illustrates the <get> response from a NETCONF RESTCONF client.";
          }
          leaf max-attempts {
            type uint8 {
              range "1..max";
            }
            default 3;
            description
             "Specifies the number times the RESTCONF server that only supports TLS, both listening for incoming
   connections as well as calling home tries to
              connect to a single application having
   two endpoints.  Please note also the configurations for
   authenticating client certificates and mappings authenticated
   certificates specific endpoint before moving on to NETCONF user names.

<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
  <session-options>
    <hello-timeout>600</hello-timeout>
    <idle-timeout>3600</idle-timeout>
  </session-options>
  <listen>
    <endpoint>
      <name>primary-netconf-endpoint</name>
      <tls>
        <address>11.22.33.44</address>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </endpoint>
  </listen>
  <call-home>
    <application>
      <name>config-mgr</name>
      <tls>
        <endpoints>
          <endpoint>
            <name>east-data-center</name>
            <address>11.22.33.44</address>
          </endpoint>
          <endpoint>
            <name>west-data-center</name>
            <address>55.66.77.88</address>
          </endpoint>
        </endpoints>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </application>
  </call-home>
  <tls>
    <client-auth>
      <trusted-ca-certs>
        <trusted-ca-cert>
          QW4gRWFzdGVyIGVnZywgZm9yIHRob3NlIHdobyBtaWdodCBsb29rICA6KQo=
        </trusted-ca-cert>
      </trusted-ca-certs>
      <trusted-client-certs>
        <trusted-client-cert>
          SSBhbSB0aGUgZWdnIG1hbiwgdGhleSBhcmUgdGhlIGVnZyBtZW4uCg==
        </trusted-client-cert>
        <trusted-client-cert>
          SSBhbSB0aGUgd2FscnVzLCBnb28gZ29vIGcnam9vYi4K
        </trusted-client-cert>
      </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>11:0A:05:11:00</fingerprint>
          <map-type>x509c2n:specified</map-type>
          <name>Joe Cool</name>
        </cert-to-name>
      </cert-maps>
    </client-auth>
  </tls>
</netconf-server>
A.3.  RESTCONF Configuration using TLS Transport

   The following example illustrates the <get> response from
              next endpoint in the list (round robin).";
          }
        }
      }
    }
  }

  grouping tls-server-grouping {
    description
      "An augmentation of tls-server-grouping, as defined in the
       ietf-tls-server module, to add in cert-maps.";
    uses ts:tls-server-grouping {
      augment "client-auth" {
        container cert-maps {
          uses x509c2n:cert-to-name;
          description
           "The cert-maps container is used by a RESTCONF NETCONF server that only supports TLS, both listening for incoming
   connections as well as calling home to
            map the NETCONF client's presented X.509 certificate to a single application having
   two endpoints.

<restconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-server">
  <listen>
    <endpoint>
      <name>primary-restconf-endpoint</name>
      <tls>
        <address>11.22.33.44</address>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </endpoint>
  </listen>
  <call-home>
    <application>
      <name>config-mgr</name>
      <tls>
        <endpoints>
          <endpoint>
            <name>east-data-center</name>
            <address>11.22.33.44</address>
          </endpoint>
          <endpoint>
            <name>west-data-center</name>
            <address>55.66.77.88</address>
          </endpoint>
        </endpoints>
        <certificates>
          <certificate>fw1.east.example.com</certificate>
        </certificates>
      </tls>
    </application>
  </call-home>
</restconf-server>
            NETCONF username.  If no matching and valid cert-to-name
            list entry can be found, then the NETCONF server MUST
            close the connection, and MUST NOT accept NETCONF
            messages over it.";
          reference
            "RFC WWWW: NETCONF over TLS, Section 7";
        }
      }
    }
  }

}

<CODE ENDS>

Appendix B.  Change Log

B.1.  00 to 01

   o  Restructured document so it flows better

   o  Added trusted-ca-certs and trusted-client-certs objects into the
      ietf-system-tls-auth module

B.2.  01 to 02

   o  removed the "one-to-many" construct

   o  removed "address" as a key field

   o  removed "network-manager" terminology

   o  moved open issues to github issues

   o  brought TLS client auth back into model

B.3.  02 to 03

   o  fixed tree diagrams and surrounding text

B.4.  03 to 04

   o  reduced the number of grouping statements

   o  removed psk-maps and associated feature statements

   o  added ability for listen/call-home instances to specify which
      host-keys/certificates (of all listed) to use

   o  clarified that last-connected should span reboots

   o  added missing "objectives" for selecting which keys to use,
      authenticating client-certificates, and mapping authenticated
      client-certificates to usernames

   o  clarified indirect client certificate authentication

   o  added keep-alive configuration for listen connections
   o  added global-level NETCONF session parameters

B.5.  04 to 05

   o  Removed all refs to the old ietf-system-tls-auth module

   o  Removed YANG 1.1 style if-feature statements (loss some
      expressiveness)

   o  Removed the read-only (config false) lists of SSH host-keys and
      TLS certs

   o  Added an if-feature around session-options container

   o  Added ability to configure trust-anchors for SSH X.509 client
      certs

   o  Now imports by revision, per best practice

   o  Added support for RESTCONF server

   o  Added RFC Editor instructions

B.6.  05 to 06

   o  Removed feature statement on the session-options container (issue
      #21).

   o  Added NACM statements to YANG modules for sensitive nodes (issue
      #24).

   o  Fixed default RESTCONF server port value to be 443 (issue #26).

   o  Added client-cert-auth subtree to ietf-restconf-server module
      (issue #27).

   o  Updated draft-ietf-netmod-snmp-cfg reference to RFC 7407 (issue
      #28).

   o  Added description statements for groupings (issue #29).

   o  Added description for braces to tree diagram section (issue #30).

   o  Renamed feature from "rfc6187" to "ssh-x509-certs" (issue #31).

B.7.  06 to 07

   o  Replaced "application" with "NETCONF/RESTCONF client" (issue #32).

   o  Reverted back to YANG 1.1 if-feature statements (issue #34).

   o  Removed import by revisions (issue #36).

   o  Removed groupings only used once (issue #37).

   o  Removed upper-bound on hello-timeout, idle-timeout, and max-
      sessions (issue #38).

   o  Clarified that when no listen address is configured, the NETCONF/
      RESTCONF server will listen on all addresses (issue #41).

   o  Update keep-alive reference to new section in Call Home draft
      (issue #42).

   o  Modified connection-type/persistent/keep-alives/interval-secs
      default value, removed the connection-type/periodic/linger-secs
      node, and also removed the reconnect-strategy/interval-secs node
      (issue #43).

   o  Clarified how last-connected reconnection type should work across
      reboots (issue #44).

   o  Clarified how DNS-expanded hostnames should be processed (issue
      #45).

   o  Removed text on how to implement keep-alives (now in the call-home
      draft) and removed the keep-alive configuration for listen
      connections (issue #46).

   o  Clarified text for .../periodic-connection/timeout-mins (issue
      #47).

   o  Fixed description on the "trusted-ca-certs" leaf-list (issue #48).

   o  Added optional keychain-based solution in appendix A (issue #49).

   o  Fixed description text for the interval-secs leaf (issue #50).

   o  moved idle-time into the listen, persistent, and periodic subtrees
      (issue #51).

   o  put presence statements on containers where it makes sense (issue
      #53).

Appendix C.  Open Issues

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

Authors' Addresses

   Kent Watsen
   Juniper Networks

   EMail: kwatsen@juniper.net

   Juergen Schoenwaelder
   Jacobs University Bremen

   EMail: j.schoenwaelder@jacobs-university.de