[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-wu-ntp-ntp-cfg) 00 01 02 03 04 05

NTP Working Group                                                  N. Wu
Internet-Draft                                                  D. Dhody
Intended status: Standards Track                                  Huawei
Expires: June 20, 2019                                          A. Sinha
                                                            A. Kumar S N
                                                            RtBrick Inc.
                                                                 Y. Zhao
                                                                Ericsson
                                                       December 17, 2018


                       A YANG Data Model for NTP
                   draft-ietf-ntp-yang-data-model-05

Abstract

   This document defines a YANG data model for Network Time Protocol
   (NTP) implementations.  The data model includes configuration data
   and state data.

Requirements Language

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

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on June 20, 2019.







Wu, et al.                Expires June 20, 2019                 [Page 1]


Internet-Draft                YANG for NTP                 December 2018


Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Operational State . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.3.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   3
     1.4.  Prefixes in Data Node Names . . . . . . . . . . . . . . .   3
   2.  NTP data model  . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Relationship with NTPv4-MIB . . . . . . . . . . . . . . . . .   8
   4.  Relationship with RFC 7317  . . . . . . . . . . . . . . . . .   8
   5.  Access Rules  . . . . . . . . . . . . . . . . . . . . . . . .   9
   6.  Key Management  . . . . . . . . . . . . . . . . . . . . . . .   9
   7.  NTP YANG Module . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Usage Example . . . . . . . . . . . . . . . . . . . . . . . .  32
     8.1.  Unicast association . . . . . . . . . . . . . . . . . . .  32
     8.2.  Refclock master . . . . . . . . . . . . . . . . . . . . .  34
     8.3.  Authentication configuration  . . . . . . . . . . . . . .  35
     8.4.  Access configuration  . . . . . . . . . . . . . . . . . .  37
     8.5.  Multicast configuration . . . . . . . . . . . . . . . . .  37
     8.6.  Manycast configuration  . . . . . . . . . . . . . . . . .  41
     8.7.  Clock state . . . . . . . . . . . . . . . . . . . . . . .  44
     8.8.  Get all association . . . . . . . . . . . . . . . . . . .  44
     8.9.  Global statistic  . . . . . . . . . . . . . . . . . . . .  46
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  46
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  47
   11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  48
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  48
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  48
     12.2.  Informative References . . . . . . . . . . . . . . . . .  50
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  50






Wu, et al.                Expires June 20, 2019                 [Page 2]


Internet-Draft                YANG for NTP                 December 2018


1.  Introduction

   This document defines a YANG [RFC7950] data model for Network Time
   Protocol [RFC5905] implementations.

   The data model convers configuration of system parameters of NTP,
   such as access rules, authentication and VPN Routing and Forwarding
   (VRF) binding, and also associations of NTP in different modes and
   parameters of per-interface.  It also provides information about
   running state of NTP implementations.

1.1.  Operational State

   NTP Operational State is included in the same tree as NTP
   configuration, consistent with Network Management Datastore
   Architecture [RFC8342].  NTP current state and statistics are also
   maintained in the operational state.  Additionally, the operational
   state also include the associations state.

1.2.  Terminology

   The terminology used in this document is aligned to [RFC5905].

1.3.  Tree Diagrams

   A simplified graphical representation of the data model is used in
   this document.  This document uses the graphical representation of
   data models defined in [RFC8340].

1.4.  Prefixes in Data Node Names

   In this document, names of data nodes and other data model objects
   are often used without a prefix, as long as it is clear from the
   context in which YANG module each name is defined.  Otherwise, names
   are prefixed using the standard prefix associated with the
   corresponding YANG module, as shown in Table 1.















Wu, et al.                Expires June 20, 2019                 [Page 3]


Internet-Draft                YANG for NTP                 December 2018


   +----------+--------------------------+-----------------------------+
   | Prefix   | YANG module              | Reference                   |
   +----------+--------------------------+-----------------------------+
   | yang     | ietf-yang-types          | [RFC6991]                   |
   | inet     | ietf-inet-types          | [RFC6991]                   |
   | if       | ietf-interfaces          | [RFC8343]                   |
   | ianach   | iana-crypt-hash          | [RFC7317]                   |
   | key-     | ietf-key-chain           | [RFC8177]                   |
   | chain    |                          |                             |
   | acl      | ietf-access-control-list | [I-D.ietf-netmod-acl-model] |
   | rt-types | ietf-routing-types       | [RFC8294]                   |
   +----------+--------------------------+-----------------------------+

             Table 1: Prefixes and corresponding YANG modules

2.  NTP data model

   This document defines the YANG module "ietf-ntp", which has the
   following structure:

  module: ietf-ntp
   +--rw ntp!
      +--rw port?                    inet:port-number {ntp-port}?
      +--rw refclock-master!
      |  +--rw master-stratum?   ntp-stratum
      +--rw authentication
      |  +--rw auth-enabled?          boolean
      |  +--rw authentication-keys* [key-id]
      |     +--rw key-id       uint32
      |     +--rw algorithm?   identityref
      |     +--rw key?         ianach:crypt-hash
      |     +--rw istrusted?   boolean
      +--rw access-rules
      |  +--rw access-rule* [access-mode]
      |     +--rw access-mode    access-mode
      |     +--rw acl?           -> /acl:acls/acl/name
      +--ro clock-state
      |  +--ro system-status
      |     +--ro clock-state                  ntp-clock-status
      |     +--ro clock-stratum                ntp-stratum
      |     +--ro clock-refid                  union
      |     +--ro associations-address?
      |     |       -> /ntp/associations/address
      |     +--ro associations-local-mode?
      |     |       -> /ntp/associations/local-mode
      |     +--ro associations-isconfigured?
      |     |       -> /ntp/associations/isconfigured
      |     +--ro nominal-freq                 decimal64



Wu, et al.                Expires June 20, 2019                 [Page 4]


Internet-Draft                YANG for NTP                 December 2018


      |     +--ro actual-freq                  decimal64
      |     +--ro clock-precision              uint8
      |     +--ro clock-offset?                decimal64
      |     +--ro root-delay?                  decimal64
      |     +--ro root-dispersion?             decimal64
      |     +--ro reference-time?              yang:date-and-time
      |     +--ro sync-state                   ntp-sync-state
      +--rw unicast-configuration* [address type]
      |  +--rw address           inet:host
      |  +--rw type              unicast-configuration-type
      |  +--rw authentication
      |  |  +--rw (authentication-type)?
      |  |     +--:(symmetric-key)
      |  |        +--rw key-id?   leafref
      |  +--rw prefer?           boolean
      |  +--rw burst?            boolean
      |  +--rw iburst?           boolean
      |  +--rw source?           if:interface-ref
      |  +--rw minpoll?          ntp-minpoll
      |  +--rw maxpoll?          ntp-maxpoll
      |  +--rw port?             inet:port-number {ntp-port}?
      |  +--rw version?          ntp-version
      +--ro associations* [address local-mode isconfigured]
      |  +--ro address           inet:host
      |  +--ro local-mode        association-mode
      |  +--ro isconfigured      boolean
      |  +--ro stratum?          ntp-stratum
      |  +--ro refid?            union
      |  +--ro authentication?
      |  |       -> /ntp/authentication/authentication-keys/key-id
      |  +--ro prefer?           boolean
      |  +--ro peer-interface?   if:interface-ref
      |  +--ro minpoll?          ntp-minpoll
      |  +--ro maxpoll?          ntp-maxpoll
      |  +--ro port?             inet:port-number {ntp-port}?
      |  +--ro version?          ntp-version
      |  +--ro reach?            uint8
      |  +--ro unreach?          uint8
      |  +--ro poll?             uint8
      |  +--ro now?              uint32
      |  +--ro offset?           decimal64
      |  +--ro delay?            decimal64
      |  +--ro dispersion?       decimal64
      |  +--ro originate-time?   yang:date-and-time
      |  +--ro receive-time?     yang:date-and-time
      |  +--ro transmit-time?    yang:date-and-time
      |  +--ro input-time?       yang:date-and-time
      |  +--ro ntp-statistics



Wu, et al.                Expires June 20, 2019                 [Page 5]


Internet-Draft                YANG for NTP                 December 2018


      |     +--ro packet-sent?        yang:counter32
      |     +--ro packet-sent-fail?   yang:counter32
      |     +--ro packet-received?    yang:counter32
      |     +--ro packet-dropped?     yang:counter32
      +--rw interfaces
      |  +--rw interface* [name]
      |     +--rw name                if:interface-ref
      |     +--rw broadcast-server!
      |     |  +--rw ttl?              uint8
      |     |  +--rw authentication
      |     |  |  +--rw (authentication-type)?
      |     |  |     +--:(symmetric-key)
      |     |  |        +--rw key-id?   leafref
      |     |  +--rw minpoll?          ntp-minpoll
      |     |  +--rw maxpoll?          ntp-maxpoll
      |     |  +--rw port?             inet:port-number {ntp-port}?
      |     |  +--rw version?          ntp-version
      |     +--rw broadcast-client!
      |     +--rw multicast-server* [address]
      |     |  +--rw address
      |     |  |       rt-types:ip-multicast-group-address
      |     |  +--rw ttl?              uint8
      |     |  +--rw authentication
      |     |  |  +--rw (authentication-type)?
      |     |  |     +--:(symmetric-key)
      |     |  |        +--rw key-id?   leafref
      |     |  +--rw minpoll?          ntp-minpoll
      |     |  +--rw maxpoll?          ntp-maxpoll
      |     |  +--rw port?             inet:port-number {ntp-port}?
      |     |  +--rw version?          ntp-version
      |     +--rw multicast-client* [address]
      |     |  +--rw address    rt-types:ip-multicast-group-address
      |     +--rw manycast-server* [address]
      |     |  +--rw address    rt-types:ip-multicast-group-address
      |     +--rw manycast-client* [address]
      |        +--rw address
      |        |       rt-types:ip-multicast-group-address
      |        +--rw authentication
      |        |  +--rw (authentication-type)?
      |        |     +--:(symmetric-key)
      |        |        +--rw key-id?   leafref
      |        +--rw ttl?              uint8
      |        +--rw minclock?         uint8
      |        +--rw maxclock?         uint8
      |        +--rw beacon?           uint8
      |        +--rw minpoll?          ntp-minpoll
      |        +--rw maxpoll?          ntp-maxpoll
      |        +--rw port?             inet:port-number {ntp-port}?



Wu, et al.                Expires June 20, 2019                 [Page 6]


Internet-Draft                YANG for NTP                 December 2018


      |        +--rw version?          ntp-version
      +--ro ntp-statistics
         +--ro packet-sent?        yang:counter32
         +--ro packet-sent-fail?   yang:counter32
         +--ro packet-received?    yang:counter32
         +--ro packet-dropped?     yang:counter32

  groupings:
  authentication
      +---- (authentication-type)?
         +--:(symmetric-key)
            +---- key-id?
                    -> /ntp/authentication/authentication-keys/key-id

  statistics
      +---- packet-sent?        yang:counter32
      +---- packet-sent-fail?   yang:counter32
      +---- packet-received?    yang:counter32
      +---- packet-dropped?     yang:counter32

  authentication-key
      +---- key-id?      uint32
      +---- algorithm?   identityref
      +---- key?         ianach:crypt-hash
      +---- istrusted?   boolean

  association-ref
      +---- associations-address?        -> /ntp/associations/address
      +---- associations-local-mode?     -> /ntp/associations/local-mode
      +---- associations-isconfigured?
              -> /ntp/associations/isconfigured

  common-attributes
      +---- minpoll?   ntp-minpoll
      +---- maxpoll?   ntp-maxpoll
      +---- port?      inet:port-number {ntp-port}?
      +---- version?   ntp-version


   This data model defines one top-level container which includes both
   the NTP configuration and the NTP running state including access
   rules, authentication, associations, unicast configurations,
   interfaces, system status and associations.








Wu, et al.                Expires June 20, 2019                 [Page 7]


Internet-Draft                YANG for NTP                 December 2018


3.  Relationship with NTPv4-MIB

   If the device implements the NTPv4-MIB [RFC5907], data nodes from
   YANG module can be mapped to table entries in NTPv4-MIB.

   The following tables list the YANG data nodes with corresponding
   objects in the NTPv4-MIB.

   YANG NTP Configuration Data Nodes and Related NTPv4-MIB Objects

   +---------------------------------+---------------------------------+
   |  YANG data nodes in /ntp/clock- |        NTPv4-MIB objects        |
   |       state/system-status       |                                 |
   +---------------------------------+---------------------------------+
   |           clock-state           |     ntpEntStatusCurrentMode     |
   |          clock-stratum          |       ntpEntStatusStratum       |
   |           clock-refid           |  ntpEntStatusActiveRefSourceId  |
   |                                 | ntpEntStatusActiveRefSourceName |
   |         clock-precision         |       ntpEntTimePrecision       |
   |           clock-offset          |     ntpEntStatusActiveOffset    |
   |         root-dispersion         |      ntpEntStatusDispersion     |
   +---------------------------------+---------------------------------+

   +---------------------------------------+---------------------------+
   | YANG data nodes in /ntp/associations/ |     NTPv4-MIB objects     |
   +---------------------------------------+---------------------------+
   |                address                |    ntpAssocAddressType    |
   |                                       |      ntpAssocAddress      |
   |                stratum                |      ntpAssocStratum      |
   |                 refid                 |       ntpAssocRefId       |
   |                 offset                |       ntpAssocOffset      |
   |                 delay                 |    ntpAssocStatusDelay    |
   |               dispersion              |  ntpAssocStatusDispersion |
   |       ntp-statistics/packet-sent      |    ntpAssocStatOutPkts    |
   |     ntp-statistics/packet-received    |     ntpAssocStatInPkts    |
   |     ntp-statistics/packet-dropped     | ntpAssocStatProtocolError |
   +---------------------------------------+---------------------------+

   YANG NTP State Data Nodes and Related NTPv4-MIB Objects

4.  Relationship with RFC 7317

   This section describes the relationship with NTP definition in
   Section 3.2 System Time Management of [RFC7317] .  YANG data nodes in
   /ntp/ also supports per-interface configurations which is not
   supported in /system/ntp.  If the yang model defined in this document
   is implemented, then /system/ntp SHOULD NOT be used and MUST be
   ignored.



Wu, et al.                Expires June 20, 2019                 [Page 8]


Internet-Draft                YANG for NTP                 December 2018


    +-------------------------------+--------------------------------+
    |    YANG data nodes in /ntp/   | YANG data nodes in /system/ntp |
    +-------------------------------+--------------------------------+
    |              ntp!             |            enabled             |
    |     unicast-configuration     |             server             |
    |                               |          server/name           |
    | unicast-configuration/address |  server/transport/udp/address  |
    |   unicast-configuration/port  |   server/transport/udp/port    |
    |   unicast-configuration/type  |    server/association-type     |
    |  unicast-configuration/iburst |         server/iburst          |
    |  unicast-configuration/prefer |         server/prefer          |
    +-------------------------------+--------------------------------+

      YANG NTP Configuration Data Nodes and counterparts in RFC 7317
                                  Objects

5.  Access Rules

   As per [RFC1305], NTP could include an access-control feature that
   prevents unauthorized access and controls which peers are allowed to
   update the local clock.  Further it is useful to differentiate
   between the various kinds of access (such as peer or server; refer
   access-mode) and attach different acl-rule to each.  For this, the
   YANG module allow such configuration via /ntp/access-rules.  The
   access-rule itself is configured via [I-D.ietf-netmod-acl-model].

6.  Key Management

   As per [RFC1305], when authentication is enabled, NTP employs a
   crypto-checksum, computed by the sender and checked by the receiver,
   together with a set of predistributed algorithms, and cryptographic
   keys indexed by a key identifier included in the NTP message.  This
   key-id is 32-bits unsigned integer that MUST be configured on the NTP
   peers before the authentication could be used.  For this reason, this
   YANG modules allow such configuration via /ntp/authentication/
   authentication-keys/. Further at the time of configuration of NTP
   association (for example unicast-server), the key-id is specefied.

7.  NTP YANG Module

 <CODE BEGINS> file "ietf-ntp@2018-12-17.yang"
 module ietf-ntp {

   yang-version 1.1;

   namespace "urn:ietf:params:xml:ns:yang:ietf-ntp";

   prefix "ntp";



Wu, et al.                Expires June 20, 2019                 [Page 9]


Internet-Draft                YANG for NTP                 December 2018


   import ietf-yang-types {
     prefix "yang";
     reference "RFC 6991";
   }

   import ietf-inet-types {
     prefix "inet";
     reference "RFC 6991";
   }

   import ietf-interfaces {
     prefix "if";
     reference "RFC 8343";
   }

   import iana-crypt-hash {
     prefix "ianach";
     reference "RFC 7317";
   }

   import ietf-key-chain {
     prefix "key-chain";
     reference "RFC 8177";
   }

   import ietf-access-control-list {
     prefix "acl";
     reference "RFC XXXX";
   }

   /* Note: The RFC Editor will replace XXXX with the number assigned
   to the RFC once draft-ietf-netmod-acl-model becomes an RFC.*/

   import ietf-routing-types {
     prefix "rt-types";
     reference "RFC 8294";

   }

   organization
     "IETF NTP (Network Time Protocol) Working Group";

   contact
     "WG Web:  <http://tools.ietf.org/wg/ntp/>
     WG List:  <mailto: ntpwg@lists.ntp.org
     Editor:   Eric Wu
               <mailto:eric.wu@huawei.com>
     Editor:   Anil Kumar S N



Wu, et al.                Expires June 20, 2019                [Page 10]


Internet-Draft                YANG for NTP                 December 2018


               <mailto:anil.ietf@gmail.com>
     Editor:   Yi Zhao
               <mailto:yi.z.zhao@ericsson.com>
     Editor:   Dhruv Dhody
               <mailto:dhruv.ietf@gmail.com>
     Editor:   Ankit Kumar Sinha
               <mailto:ankit.ietf@gmail.com>";
   description
     "This document defines a YANG data model for Network Time Protocol
     (NTP) implementations. The data model includes configuration data
     and state data.

     Copyright (c) 2018 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 YYYY;
     see the RFC itself for full legal notices.";

   revision 2018-12-17 {
     description
       "Updated revision.";
     reference
       "RFC YYYY: A YANG Data Model for NTP.";
   }

   /* Note: The RFC Editor will replace YYYY with the number assigned
   to this document once it becomes an RFC.*/

   /* Typedef Definitions */

   typedef ntp-stratum {
     type uint8 {
       range "1..16";
     }
     description
       "The level of each server in the hierarchy is defined by
       a stratum. Primary servers are assigned with stratum
       one; secondary servers at each lower level are assigned with
       one stratum greater than the preceding level";
   }




Wu, et al.                Expires June 20, 2019                [Page 11]


Internet-Draft                YANG for NTP                 December 2018


   typedef ntp-version {
     type uint8 {
       range "1..4";
     }
     default "3";
     description
       "The current NTP version supported by corresponding
       association.";
   }

   typedef ntp-minpoll {
     type uint8 {
       range "4..17";
     }
     default "6";
     description
       "The minimum poll exponent for this NTP association.";
   }

   typedef ntp-maxpoll {
     type uint8 {
       range "4..17";
     }
     default "10";
     description
       "The maximum poll exponent for this NTP association.";
   }

   typedef access-mode {
     type enumeration {
       enum peer {
         value "0";
         description
           "Enables the full access authority. Both time
           request and control query can be performed
           on the local NTP service, and the local clock
           can be synchronized with the remote server.";
       }
       enum server {
         value "1";
         description
           "Enables the server access and query.
           Both time requests and control query can be
           performed on the local NTP service, but the
           local clock cannot be synchronized with the
           remote server.";
       }
       enum synchronization {



Wu, et al.                Expires June 20, 2019                [Page 12]


Internet-Draft                YANG for NTP                 December 2018


         value "2";
         description
           "Enables the server to access.
           Only time request can be performed on the
           local NTP service.";
       }
       enum query {
         value "3";
         description
           "Enables the maximum access limitation.
           Control query can be performed only on the
           local NTP service.";
       }
     }
     description
       "This defines NTP access modes.";
   }

   typedef unicast-configuration-type {
     type enumeration {
       enum server {
         value "0";
         description
           "Use client association mode. This device
           will not provide synchronization to the
           configured NTP server.";
       }
       enum peer {
         value "1";
         description
           "Use symmetric active association mode.
           This device may provide synchronization
           to the configured NTP server.";
       }
     }
     description
       "This defines NTP unicast mode of operation.";
   }
   typedef association-mode {
     type enumeration {
       enum client {
         value "0";
         description
           "Use client association mode(mode 3).
           This device will not provide synchronization
           to the configured NTP server.";
       }
       enum active {



Wu, et al.                Expires June 20, 2019                [Page 13]


Internet-Draft                YANG for NTP                 December 2018


         value "1";
         description
           "Use symmetric active association mode(mode 1).
           This device may synchronize with its NTP peer,
           or provide synchronization to configured NTP peer.";
       }
       enum passive {
         value "2";
         description
           "Use symmetric passive association mode(mode 2).
           This device has learned this association dynamically.
           This device may synchronize with its NTP peer.";
       }
       enum broadcast {
         value "3";
         description
           "Use broadcast mode(mode 5).
           This mode defines that its either working
           as broadcast-server or multicast-server.";
       }
       enum broadcast-client {
         value "4";
         description
           "This mode defines that its either working
           as broadcast-client or multicast-client.";
       }
     }
     description
       "The NTP association modes.";
   }

   typedef ntp-clock-status {
     type enumeration {
       enum synchronized {
         value "0";
         description
           "Indicates that the local clock has been
           synchronized with an NTP server or
           the reference clock.";
       }
       enum unsynchronized {
         value "1";
         description
           "Indicates that the local clock has not been
           synchronized with any NTP server.";
       }
     }
     description



Wu, et al.                Expires June 20, 2019                [Page 14]


Internet-Draft                YANG for NTP                 December 2018


       "This defines NTP clock status.";
   }

   typedef ntp-sync-state {
     type enumeration {
       enum clock-not-set {
         value "0";
         description
           "Indicates the clock is not updated.";
       }
       enum freq-set-by-cfg {
         value "1";
         description
           "Indicates the clock frequency is set by
           NTP configuration.";
       }
       enum clock-set {
         value "2";
         description
           "Indicates the clock is set.";
       }
       enum freq-not-determined {
         value "3";
         description
           "Indicates the clock is set but the frequency
           is not determined.";
       }
       enum clock-synchronized {
         value "4";
         description
           "Indicates that the clock is synchronized";
       }
       enum spike {
         value "5";
         description
           "Indicates a time difference of more than 128
           milliseconds is detected between NTP server
           and client clock. The clock change will take
           effect in XXX seconds.";
       }
     }
     description
       "This defines NTP clock sync states.";
   }

   /* features */
   feature ntp-port {
     description



Wu, et al.                Expires June 20, 2019                [Page 15]


Internet-Draft                YANG for NTP                 December 2018


       "Support for NTP port configuration";
     reference "RFC1305 - 3.2.7 Parameters";
   }

   feature authentication {
     description
       "Support for NTP symmetric key authentication";
     reference "RFC1305 - 3.2.6 Authentication Variables";
   }

   feature access-rules {
     description
       "Support for NTP access control";
     reference "RFC1305 - 3.6 Access Control Issues";
   }

   feature unicast-configuration {
     description
       "Support for NTP client/server or active/passive
       in unicast";
     reference "RFC1305 - 3.3 Modes of Operation";
   }

   feature broadcast-server {
     description
       "Support for broadcast server";
     reference "RFC1305 - 3.3 Modes of Operation";
   }

   feature broadcast-client {
     description
       "Support for broadcast client";
     reference "RFC1305 - 3.3 Modes of Operation";
   }

   feature multicast-server {
     description
       "Support for multicast server";
     reference "RFC1305 - 3.3 Modes of Operation";
   }

   feature multicast-client {
     description
       "Support for multicast client";
     reference "RFC1305 - 3.3 Modes of Operation";
   }

   feature manycast-server {



Wu, et al.                Expires June 20, 2019                [Page 16]


Internet-Draft                YANG for NTP                 December 2018


     description
       "Support for manycast server";
     reference "RFC5905 - 3.1 Dynamic Server Discovery";
   }

   feature manycast-client {
     description
       "Support for manycast client";
     reference "RFC5905 - 3.1 Dynamic Server Discovery";
   }

   /* Groupings */
   grouping authentication-key {
     description
       "To define an authentication key for a Network Time
       Protocol (NTP) time source.";
     leaf key-id {
       type uint32 {
         range "1..max";
       }
       description
         "Authentication key identifier.";
     }
     leaf algorithm {
       type identityref {
         base key-chain:crypto-algorithm;
       }
       description
         "Authentication algorithm.";
     }
     leaf key {
       type ianach:crypt-hash;
       description
         "The key";
     }
     leaf istrusted {
       type boolean;
       description
         "Key-id is trusted or not";
     }
   }

   grouping authentication {
     description
       "Authentication.";
     choice authentication-type {
       description
         "Type of authentication.";



Wu, et al.                Expires June 20, 2019                [Page 17]


Internet-Draft                YANG for NTP                 December 2018


       case symmetric-key {
         leaf key-id {
           type leafref {
             path "/ntp:ntp/ntp:authentication/"
             + "ntp:authentication-keys/ntp:key-id";
           }
           description
             "Authentication key id referenced in this
             association.";
         }
       }
     }
   }

   grouping statistics {
     description
       "NTP packet statistic.";
     leaf packet-sent {
       type yang:counter32;
       description
         "The total number of NTP packets delivered to the
         transport service by this NTP entity for this
         association.
         Discountinuities in the value of this counter can occur
         upon cold start or reinitialization of the NTP entity, the
         management system and at other times as indicated by
         discontinuities in the value of sysUpTime.";
     }
     leaf packet-sent-fail {
       type yang:counter32;
       description
         "The number of times NTP packets sending failed.";
     }
     leaf packet-received {
       type yang:counter32;
       description
         "The total number of NTP packets delivered to the
         NTP entity from this association.
         Discountinuities in the value of this counter can occur
         upon cold start or reinitialization of the NTP entity, the
         management system and at other times as indicated by
         discontinuities in the value of sysUpTime.";
     }
     leaf packet-dropped {
       type yang:counter32;
       description
         "The total number of NTP packets that were delivered
         to this NTP entity from this association and this entity



Wu, et al.                Expires June 20, 2019                [Page 18]


Internet-Draft                YANG for NTP                 December 2018


         was not able to process due to an NTP protocol error.
         Discountinuities in the value of this counter can occur
         upon cold start or reinitialization of the NTP entity, the
         management system and at other times as indicated by
         discontinuities in the value of sysUpTime.";
     }
   }

   grouping common-attributes {
     description
       "NTP common attributes for configuration.";
     leaf minpoll {
       type ntp-minpoll;
       description
         "The minimum poll interval used in this association.";
     }
     leaf maxpoll {
       type ntp-maxpoll;
       description
         "The maximum poll interval used in this association.";
     }
     leaf port {
       if-feature ntp-port;
       type inet:port-number {
         range "123 | 1025..max";
       }
       default "123";
       description
         "Specify the port used to send NTP packets.";
     }
     leaf version {
       type ntp-version;
       description
         "NTP version.";
     }
   }

   grouping association-ref {
     description
       "Reference to NTP association mode";
     leaf associations-address {
       type leafref {
         path "/ntp:ntp/ntp:associations/ntp:address";
       }
       description
         "Indicates the association's address
         which result in clock synchronization.";
     }



Wu, et al.                Expires June 20, 2019                [Page 19]


Internet-Draft                YANG for NTP                 December 2018


     leaf associations-local-mode {
       type leafref {
         path "/ntp:ntp/ntp:associations/ntp:local-mode";
       }
       description
         "Indicates the association's local-mode
         which result in clock synchronization.";
     }
     leaf associations-isconfigured {
       type leafref {
         path "/ntp:ntp/ntp:associations/"
         + "ntp:isconfigured";
       }
       description
         "The association was configured or dynamic
         which result in clock synchronization.";
     }
   }

   /* Configuration data nodes */
   container ntp {
     presence
       "NTP is enabled and system should attempt to
       synchronize the system clock with an NTP server
       from the 'ntp/associations' list.";
     description
       "Configuration parameters for NTP.";
     leaf port {
       if-feature ntp-port;
       type inet:port-number {
         range "123 | 1025..max";
       }
       default "123";
       description
         "Specify the port used to send and receive NTP packets.";
     }
     container refclock-master {
       presence
         "NTP master clock is enabled.";
       description
         "Configures the local clock of this device as NTP server.";
       leaf master-stratum {
         type ntp-stratum;
         default "16";
         description
           "Stratum level from which NTP
           clients get their time synchronized.";
       }



Wu, et al.                Expires June 20, 2019                [Page 20]


Internet-Draft                YANG for NTP                 December 2018


     }
     container authentication {
       description
         "Configuration of authentication.";
       leaf auth-enabled {
         type boolean;
         default false;
         description
           "Controls whether NTP authentication is enabled
           or disabled on this device.";
       }
       list authentication-keys {
         key "key-id";
         uses authentication-key;
         description
           "List of authentication keys.";
       }
     }

     container access-rules {
       description
         "Configuration to control access to NTP service
         by using NTP access-group feature.
         The access-mode identifies how the acl is
         applied with NTP.";
       list access-rule {
         key "access-mode";
         description
           "List of access rules.";
         leaf access-mode {
           type access-mode;
           description
             "NTP access mode. The defination of each possible values:
             peer(0): Both time request and control query can be
             performed.
             server(1): Enables the server access and query.
             synchronization(2): Enables the server access only.
             query(3): Enables control query only.";
         }
         leaf acl {
           type leafref {
             path "/acl:acls/acl:acl/acl:name";
           }
           description
             "Control access configuration to be used.";
         }
         reference
           "RFC 1305";



Wu, et al.                Expires June 20, 2019                [Page 21]


Internet-Draft                YANG for NTP                 December 2018


       }
     }

     container clock-state {
       config "false";
       description
         "Clock operational state of the NTP.";

       container system-status {
         description
           "System status of NTP.";
         leaf clock-state {
           type ntp-clock-status;
           mandatory true;
           description
             "The state of system clock. The definition of each
             possible value is:
             synchronized(0): Indicates local clock is synchronized.
             unsynchronized(1): Indicates local clock is not
             synchronized.";
         }
         leaf clock-stratum {
           type ntp-stratum;
           mandatory true;
           description
             "The NTP entity's own stratum value. Should be a stratum
             of syspeer + 1 (or 16 if no syspeer).";
         }
         leaf clock-refid {
           type union {
             type inet:ipv4-address;
             type binary {
               length "4";
             }
             type string {
               length "4";
             }
           }
           mandatory true;
           description
             "IPv4 address or first 32 bits of the MD5 hash of
             the IPv6 address or reference clock of the peer to
             which clock is synchronized.";
         }

         uses association-ref {
           description
             "Reference to Association.";



Wu, et al.                Expires June 20, 2019                [Page 22]


Internet-Draft                YANG for NTP                 December 2018


         }
         leaf nominal-freq {
           type decimal64 {
             fraction-digits 4;
           }
           units Hz;
           mandatory true;
           description
             "The nominal frequency of the
             local clock.";
         }
         leaf actual-freq {
           type decimal64 {
             fraction-digits 4;
           }
           units Hz;
           mandatory true;
           description
             "The actual frequency of the
             local clock.";
         }
         leaf clock-precision {
           type uint8;
           units Hz;
           mandatory true;
           description
             "Clock precision of this system in integer format
             (prec=2^(-n)). A value of 5 would mean 2^-5 = 31.25 ms.";
         }
         leaf clock-offset {
           type decimal64 {
             fraction-digits 3;
           }
           units milliseconds;
           description
             "The time offset to the current selected reference time
             source e.g., '0.032' or '1.232'.";
         }
         leaf root-delay {
           type decimal64 {
             fraction-digits 3;
           }
           units milliseconds;
           description
             "Total delay along the path to root clock.";
         }
         leaf root-dispersion {
           type decimal64 {



Wu, et al.                Expires June 20, 2019                [Page 23]


Internet-Draft                YANG for NTP                 December 2018


             fraction-digits 3;
           }
           units milliseconds;
           description
             "The dispersion between the local clock
             and the root clock, e.g., '6.927'.";
         }
         leaf reference-time {
           type yang:date-and-time;
           description
             "The reference timestamp.";
         }
         leaf sync-state {
           type ntp-sync-state;
           mandatory true;
           description
             "The synchronization status of
             the local clock.";
         }
       }
     }
     list unicast-configuration {
       key "address type";
       description
         "List of NTP unicast-configurations.";
       leaf address {
         type inet:host;
         description
           "Address of this association.";
       }
       leaf type {
         type unicast-configuration-type;
         description
           "Use client association mode.  This device
           will not provide synchronization to the
           configured NTP server.";
       }
       container authentication{
         description
           "Authentication used for this association.";
         uses authentication;
       }
       leaf prefer {
         type boolean;
         default "false";
         description
           "Whether this association is preferred or not.";
       }



Wu, et al.                Expires June 20, 2019                [Page 24]


Internet-Draft                YANG for NTP                 December 2018


       leaf burst {
         type boolean;
         default "false";
         description
           "If set, a series of packets are sent instead of a single
           packet within each synchronization interval to achieve faster
           synchronization.";
       }
       leaf iburst {
         type boolean;
         default "false";
         description
           "If set, a series of packets are sent instead of a single
           packet within the initial synchronization interval to achieve
           faster initial synchronization.";
       }
       leaf source {
         type if:interface-ref;
         description
           "The interface whose IP address is used by this association
           as the source address.";
       }
       uses common-attributes {
         description
           "Common attributes like port, version, min and max
           poll.";
       }
     }
     list associations {
       key "address local-mode isconfigured";
       config "false";
       description
         "List of NTP associations. Here address, local-mode
         and isconfigured is required to uniquely identify
         a particular association. Lets take following examples -

         1) If RT1 acting as broadcast server,
         and RT2 acting as broadcast client, then RT2
         will form dynamic association with address as RT1,
         local-mode as client and isconfigured as false.

         2) When RT2 is configured
         with unicast-server RT1, then RT2 will form
         association with address as RT1, local-mode as client
         and isconfigured as true.

         Thus all 3 leaves are needed as key to unique identify
         the association.";



Wu, et al.                Expires June 20, 2019                [Page 25]


Internet-Draft                YANG for NTP                 December 2018


       leaf address {
         type inet:host;
         description
           "The address of this association. Represents the IP
           address of a unicast/multicast/broadcast address.";
       }
       leaf local-mode {
         type association-mode;
         description
           "Local mode of this NTP association.";
       }
       leaf isconfigured {
         type boolean;
         description
           "Indicates if this association is configured or
           dynamically learned.";
       }
       leaf stratum {
         type ntp-stratum;
         description
           "The association stratum value.";
       }
       leaf refid {
         type union {
           type inet:ipv4-address;
           type binary {
             length "4";
           }
           type string {
             length "4";
           }
         }
         description
           "The refclock driver ID, if available.
           -- a refclock driver ID like '127.127.1.0' for local clock
              sync
           -- uni/multi/broadcast associations will look like '20.1.1.1'
           -- sync with primary source will look like 'DCN', 'NIST',
              'ATOM'";
         reference
           "RFC 1305";
       }
       leaf authentication{
         type leafref {
           path "/ntp:ntp/ntp:authentication/"
           + "ntp:authentication-keys/ntp:key-id";
         }
         description



Wu, et al.                Expires June 20, 2019                [Page 26]


Internet-Draft                YANG for NTP                 December 2018


           "Authentication Key used for this association.";
       }
       leaf prefer {
         type boolean;
         default "false";
         description
           "Indicates if this association is preferred.";
       }
       leaf peer-interface {
         type if:interface-ref;
         description
           "The interface which is used for communication.";
       }
       uses common-attributes {
         description
           "Common attributes like port, version, min and
           max poll.";
       }
       leaf reach {
         type uint8;
         description
           "The reachability of the configured
           server or peer.";
       }
       leaf unreach {
         type uint8;
         description
           "The unreachability of the configured
           server or peer.";
       }
       leaf poll {
         type uint8;
         units seconds;
         description
           "The polling interval for current association";
       }
       leaf now {
         type uint32;
         units seconds;
         description
           "The time since the NTP packet was
           not received or last synchronized.";
       }
       leaf offset {
         type decimal64 {
           fraction-digits 3;
         }
         units milliseconds;



Wu, et al.                Expires June 20, 2019                [Page 27]


Internet-Draft                YANG for NTP                 December 2018


         description
           "The offset between the local clock
           and the peer clock, e.g., '0.032' or '1.232'";
       }
       leaf delay {
         type decimal64 {
           fraction-digits 3;
         }
         units milliseconds;
         description
           "The network delay between the local clock
           and the peer clock.";
       }
       leaf dispersion {
         type decimal64 {
           fraction-digits 3;
         }
         units milliseconds;
         description
           "The root dispersion between the local clock
            and the peer clock.";
       }
       leaf originate-time {
         type yang:date-and-time;
         description
           "This is the local time, in timestamp format,
           when latest NTP packet was sent to peer(T1).";
         reference
           "RFC 1305";
       }
       leaf receive-time {
         type yang:date-and-time;
         description
           "This is the local time, in timestamp format,
           when latest NTP packet arrived at peer(T2).
           If the peer becomes unreachable the value is set to zero.";
         reference
           "RFC 1305";
       }
       leaf transmit-time {
         type yang:date-and-time;
         description
           "This is the local time, in timestamp format,
           at which the NTP packet departed the peer(T3).
           If the peer becomes unreachable the value is set to zero.";
         reference
           "RFC 1305";
       }



Wu, et al.                Expires June 20, 2019                [Page 28]


Internet-Draft                YANG for NTP                 December 2018


       leaf input-time {
         type yang:date-and-time;
         description
           "This is the local time, in timestamp format,
           when the latest NTP message from the peer arrived(T4).
           If the peer becomes unreachable the value is set to zero.";
         reference
           "RFC 1305";
       }
       container ntp-statistics {
         description
           "Per Peer packet send and receive statistics.";
         uses statistics {
           description
             "NTP send and receive packet statistics.";
         }
       }
     }

     container interfaces {
       description
         "Configuration parameters for NTP interfaces.";
       list interface {
         key "name";
         description
           "List of interfaces.";
         leaf name {
           type if:interface-ref;
           description
             "The interface name.";
         }

         container broadcast-server {
           presence
             "NTP broadcast-server is configured";
           description
             "Configuration of broadcast server.";
           leaf ttl {
             type uint8;
             description
               "Specifies the time to live (TTL) for a
               broadcast packet.";
           }
           container authentication{
             description
               "Authentication used for this association.";
               uses authentication;
           }



Wu, et al.                Expires June 20, 2019                [Page 29]


Internet-Draft                YANG for NTP                 December 2018


           uses common-attributes {
             description
               "Common attribute like port, version, min and
               max poll.";
           }
         }

         container broadcast-client {
           presence
             "NTP broadcast-client is configured.";
           description
             "Configuration of broadcast-client.";
         }

         list multicast-server {
           key "address";
           description
             "Configuration of multicast server.";
           leaf address {
             type rt-types:ip-multicast-group-address;
             description
               "The IP address to send NTP multicast packets.";
           }
           leaf ttl {
             type uint8;
             description
               "Specifies the time to live (TTL) for a
               multicast packet.";
           }
           container authentication{
             description
               "Authentication used for this association.";
               uses authentication;
           }
           uses common-attributes {
             description
               "Common attributes like port, version, min and
               max poll.";
           }
         }
         list multicast-client {
           key "address";
           description
             "Configuration of multicast-client.";
           leaf address {
             type rt-types:ip-multicast-group-address;
             description
               "The IP address of the multicast group to



Wu, et al.                Expires June 20, 2019                [Page 30]


Internet-Draft                YANG for NTP                 December 2018


               join.";
           }
         }
         list manycast-server {
           key "address";
           description
             "Configuration of manycast server.";
           leaf address {
             type rt-types:ip-multicast-group-address;
             description
               "The multicast group IP address to receive
               manycast client messages.";
           }
           reference
             "RFC 5905";
         }
         list manycast-client {
           key "address";
           description
             "Configuration of manycast-client.";
           leaf address {
             type rt-types:ip-multicast-group-address;
             description
               "The group IP address that the manycast client
               broadcasts the request message to.";
           }
           container authentication{
             description
               "Authentication used for this association.";
             uses authentication;
           }
           leaf ttl {
             type uint8;
             description
               "Specifies the maximum time to live (TTL) for
               the expanding ring search.";
           }
           leaf minclock {
             type uint8;
             description
               "The minimum manycast survivors in this
               association.";
           }
           leaf maxclock {
             type uint8;
             description
               "The maximum manycast candidates in this
               association.";



Wu, et al.                Expires June 20, 2019                [Page 31]


Internet-Draft                YANG for NTP                 December 2018


           }
           leaf beacon {
             type uint8;
             description
               "The maximum interval between beacons in this
               association.";
           }
           uses common-attributes {
             description
               "Common attributes like port, version, min and
               max poll.";
           }
           reference
             "RFC 5905";
         }
       }
     }
     container ntp-statistics {
       config "false";
       description
         "Total NTP packet statistics.";
       uses statistics {
         description
           "NTP send and receive packet statistics.";
       }
     }
   }
 }
 <CODE ENDS>

8.  Usage Example

8.1.  Unicast association

   Below is the example on how to configure a preferred unicast server
   present at 192.0.2.1 running at port 1025 with authentication-key 10
   and version 4














Wu, et al.                Expires June 20, 2019                [Page 32]


Internet-Draft                YANG for NTP                 December 2018


     <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
       <target>
         <running/>
       </target>
       <config>
         <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
           <unicast-configuration>
             <address>192.0.2.1</address>
             <type>server</type>
             <prefer>true</prefer>
             <version>4</version>
             <port>1025</port>
             <authentication>
               <symmetric-key>
                 <key-id>10</key-id>
               </symmetric-key>
             </authentication>
           </unicast-configuration>
         </ntp>
       </config>
     </edit-config>

   An example with IPv6 would used the an IPv6 address (say 2001:DB8::1)
   in the "address" leaf with no change in any other data tree.

   Below is the example on how to get unicast configuration

   <get>
     <filter type="subtree">
     <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:unicast-configuration>
         </sys:unicast-configuration>
     </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <unicast-configuration>
         <address>192.0.2.1</address>
         <type>server</type>
           <authentication>
             <symmetric-key>
               <key-id>10</key-id>
             </symmetric-key>
           </authentication>
         <prefer>true</prefer>
         <burst>false</burst>



Wu, et al.                Expires June 20, 2019                [Page 33]


Internet-Draft                YANG for NTP                 December 2018


         <iburst>true</iburst>
         <source/>
         <minpoll>6</minpoll>
         <maxpoll>10</maxpoll>
         <port>1025</port>
         <version>4</version>
         <stratum>9</stratum>
         <refid>20.1.1.1</refid>
         <reach>255</reach>
         <unreach>0</unreach>
         <poll>128</poll>
         <now>10</now>
         <offset>0.025</offset>
         <delay>0.5</delay>
         <dispersion>0.6</dispersion>
         <originate-time>10-10-2017 07:33:55.253 Z+05:30\
         </originate-time>
         <receive-time>10-10-2017 07:33:55.258 Z+05:30\
         </receive-time>
         <transmit-time>10-10-2017 07:33:55.300 Z+05:30\
         </transmit-time>
         <input-time>10-10-2017 07:33:55.305 Z+05:30\
         </input-time>
         <ntp-statistics>
           <packet-sent>20</packet-sent>
           <packet-sent-fail>0</packet-sent-fail>
           <packet-received>20</packet-received>
           <packet-dropped>0</packet-dropped>
         </ntp-statistics>
       </unicast-configuration>
     </ntp>
   </data>

8.2.  Refclock master

   Below is the example on how to configure reference clock with stratum
   8














Wu, et al.                Expires June 20, 2019                [Page 34]


Internet-Draft                YANG for NTP                 December 2018


   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <refclock-master>
           <master-stratum>8</master-stratum>
         </refclock-master>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get reference clock configuration

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:refclock-master>
         </sys:refclock-master>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <refclock-master>
         <master-stratum>8</master-stratum>
       </refclock-master>
     </ntp>
   </data>

8.3.  Authentication configuration

   Below is the example on how to enable authentication and configure
   trusted authentication key 10 with mode as md5 and key as abcd















Wu, et al.                Expires June 20, 2019                [Page 35]


Internet-Draft                YANG for NTP                 December 2018


   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <authentication>
           <auth-enabled>true</auth-enabled>
           <authentication-keys>
             <key-id>10</key-id>
             <algorithm>md5</algorithm>
             <key>abcd</key>
             <istrusted>true</istrusted>
           </authentication-keys>
         </authentication>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get authentication related
   configuration

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:authentication>
         </sys:authentication>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <authentication>
         <auth-enabled>false</auth-enabled>
         <trusted-keys/>
         <authentication-keys>
           <key-id>10</key-id>
           <algorithm>md5</algorithm>
           <key>abcd</key>
           <istrusted>true</istrusted>
         </authentication-keys>
       </authentication>
     </ntp>
   </data>






Wu, et al.                Expires June 20, 2019                [Page 36]


Internet-Draft                YANG for NTP                 December 2018


8.4.  Access configuration

   Below is the example on how to configure access mode "peer"
   associated with acl 2000.

   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <access-rules>
           <access-rule>
             <access-mode>peer</access-mode>
             <acl>2000</acl>
           </access-rule>
         </access-rules>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get access related configuration

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:access-rules>
         </sys:access-rules>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <access-rules>
         <access-rule>
           <access-mode>peer</access-mode>
           <acl>2000</acl>
         </access-rule>
       </access-rules>
     </ntp>
   </data>

8.5.  Multicast configuration

   Below is the example on how to configure multicast-server with
   address as "224.1.1.1", port as 1025 and authentication keyid as 10




Wu, et al.                Expires June 20, 2019                [Page 37]


Internet-Draft                YANG for NTP                 December 2018


   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <interfaces>
           <interface>
             <name>Ethernet3/0/0</name>
             <multicast-server>
               <address>224.1.1.1</address>
               <authentication>
                 <symmetric-key>
                   <key-id>10</key-id>
                 </symmetric-key>
               </authentication>
               <port>1025</port>
             </multicast-server>
           </interface>
         </interfaces>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get multicast-server related
   configuration

























Wu, et al.                Expires June 20, 2019                [Page 38]


Internet-Draft                YANG for NTP                 December 2018


   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:interfaces>
           <sys:interface>
             <sys:multicast-server>
             </sys:multicast-server>
           </sys:interface>
         </sys:interfaces>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <interfaces>
         <interface>
           <name>Ethernet3/0/0</name>
           <multicast-server>
             <address>224.1.1.1</address>
             <ttl>224.1.1.1</ttl>
             <authentication>
               <symmetric-key>
                 <key-id>10</key-id>
               </symmetric-key>
             </authentication>
             <minpoll>6</minpoll>
             <maxpoll>10</maxpoll>
             <port>1025</port>
             <version>3</version>
           </multicast-server>
         </interface>
       </interfaces>
     </ntp>
   </data>

   Below is the example on how to configure multicast-client with
   address as "224.1.1.1"













Wu, et al.                Expires June 20, 2019                [Page 39]


Internet-Draft                YANG for NTP                 December 2018


   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <interfaces>
           <interface>
             <name>Ethernet3/0/0</name>
             <multicast-client>
               <address>224.1.1.1</address>
             </multicast-client>
           </interface>
         </interfaces>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get multicast-client related
   configuration

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:interfaces>
           <sys:interface>
             <sys:multicast-client>
             </sys:multicast-client>
           </sys:interface>
         </sys:interfaces>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <interfaces>
         <interface>
           <name>Ethernet3/0/0</name>
           <multicast-client>
             <address>224.1.1.1</address>
           </multicast-client>
         </interface>
       </interfaces>
     </ntp>
   </data>





Wu, et al.                Expires June 20, 2019                [Page 40]


Internet-Draft                YANG for NTP                 December 2018


8.6.  Manycast configuration

   Below is the example on how to configure manycast-client with address
   as "224.1.1.1", port as 1025 and authentication keyid as 10

   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <interfaces>
           <interface>
             <name>Ethernet3/0/0</name>
             <manycast-client>
               <address>224.1.1.1</address>
               <authentication>
                 <symmetric-key>
                   <key-id>10</key-id>
                 </symmetric-key>
               </authentication>
               <port>1025</port>
             </manycast-client>
           </interface>
         </interfaces>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get manycast-client related
   configuration




















Wu, et al.                Expires June 20, 2019                [Page 41]


Internet-Draft                YANG for NTP                 December 2018


   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:interfaces>
           <sys:interface>
             <sys:manycast-client>
             </sys:manycast-client>
           </sys:interface>
         </sys:interfaces>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <interfaces>
         <interface>
           <name>Ethernet3/0/0</name>
           <manycast-client>
             <address>224.1.1.1</address>
             <authentication>
               <symmetric-key>
                 <key-id>10</key-id>
               </symmetric-key>
             </authentication>
             <ttl>255</ttl>
             <minclock>3</minclock>
             <maxclock>10</maxclock>
             <beacon>6</beacon>
             <minpoll>6</minpoll>
             <maxpoll>10</maxpoll>
             <port>1025</port>
           </manycast-client>
         </interface>
       </interfaces>
     </ntp>
   </data>

   Below is the example on how to configure manycast-server with address
   as "224.1.1.1"











Wu, et al.                Expires June 20, 2019                [Page 42]


Internet-Draft                YANG for NTP                 December 2018


   <edit-config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <target>
       <running/>
     </target>
     <config>
       <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <interfaces>
           <interface>
             <name>Ethernet3/0/0</name>
             <manycast-server>
               <address>224.1.1.1</address>
             </manycast-server>
           </interface>
         </interfaces>
       </ntp>
     </config>
   </edit-config>

   Below is the example on how to get manycast-server related
   configuration

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:interfaces>
           <sys:interface>
             <sys:manycast-server>
             </sys:manycast-server>
           </sys:interface>
         </sys:interfaces>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <interfaces>
         <interface>
           <name>Ethernet3/0/0</name>
           <manycast-server>
             <address>224.1.1.1</address>
           </manycast-server>
         </interface>
       </interfaces>
     </ntp>
   </data>





Wu, et al.                Expires June 20, 2019                [Page 43]


Internet-Draft                YANG for NTP                 December 2018


8.7.  Clock state

   Below is the example on how to get clock current state

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:clock-state>
         </sys:clock-state>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <clock-state>
         <system-status>
           <clock-state>synchronized</clock-state>
           <clock-stratum>7</clock-stratum>
           <clock-refid>192.0.2.1</clock-refid>
           <associations-address>192.0.2.1\
           </associations-address>
           <associations-local-mode>client\
           </associations-local-mode>
           <associations-isconfigured>yes\
           </associations-isconfigured>
           <nominal-freq>100.0</nominal-freq>
           <actual-freq>100.0</actual-freq>
           <clock-precision>18</clock-precision>
           <clock-offset>0.025</clock-offset>
           <root-delay>0.5</root-delay>
           <root-dispersion>0.8</root-dispersion>
           <reference-time>10-10-2017 07:33:55.258 Z+05:30\
           </reference-time>
           <sync-state>clock-synchronized</sync-state>
         </system-status>
       </clock-state>
     </ntp>
   </data>

8.8.  Get all association

   Below is the example on how to get all association present








Wu, et al.                Expires June 20, 2019                [Page 44]


Internet-Draft                YANG for NTP                 December 2018


   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:associations>
         </sys:associations>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <associations>
         <address>192.0.2.1</address>
         <stratum>9</stratum>
         <refid>20.1.1.1</refid>
         <local-mode>client</local-mode>
         <isconfigured>true</isconfigured>
         <authentication-key>10</authentication-key>
         <prefer>true</prefer>
         <peer-interface>Ethernet3/0/0</peer-interface>
         <minpoll>6</minpoll>
         <maxpoll>10</maxpoll>
         <port>1025</port>
         <version>4</version>
         <reach>255</reach>
         <unreach>0</unreach>
         <poll>128</poll>
         <now>10</now>
         <offset>0.025</offset>
         <delay>0.5</delay>
         <dispersion>0.6</dispersion>
         <originate-time>10-10-2017 07:33:55.253 Z+05:30\
         </originate-time>
         <receive-time>10-10-2017 07:33:55.258 Z+05:30\
         </receive-time>
         <transmit-time>10-10-2017 07:33:55.300 Z+05:30\
         </transmit-time>
         <input-time>10-10-2017 07:33:55.305 Z+05:30\
         </input-time>
         <ntp-statistics>
           <packet-sent>20</packet-sent>
           <packet-sent-fail>0</packet-sent-fail>
           <packet-received>20</packet-received>
           <packet-dropped>0</packet-dropped>
         </ntp-statistics>
       </associations>
     </ntp>
   </data>



Wu, et al.                Expires June 20, 2019                [Page 45]


Internet-Draft                YANG for NTP                 December 2018


8.9.  Global statistic

   Below is the example on how to get clock current state

   <get>
     <filter type="subtree">
       <sys:ntp xmlns:sys="urn:ietf:params:xml:ns:yang:ietf-ntp">
         <sys:ntp-statistics>
         </sys:ntp-statistics>
       </sys:ntp>
     </filter>
   </get>

   <data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
       <ntp-statistics>
         <packet-sent>30</packet-sent>
         <packet-sent-fail>5</packet-sent-fail>
         <packet-received>20</packet-received>
         <packet-dropped>2</packet-dropped>
       </ntp-statistics>
     </ntp>
   </data>

9.  IANA Considerations

   This document registers a URI in the "IETF XML Registry" [RFC3688].
   Following the format in RFC 3688, the following registration has been
   made.

   URI: urn:ietf:params:xml:ns:yang:ietf-ntp

   Registrant Contact: The NTP WG of the IETF.

   XML: N/A; the requested URI is an XML namespace.

   This document registers a YANG module in the "YANG Module Names"
   registry [RFC6020].

   Name: ietf-ntp

   Namespace: urn:ietf:params:xml:ns:yang:ietf-ntp

   Prefix: ntp

   Reference: RFC YYYY





Wu, et al.                Expires June 20, 2019                [Page 46]


Internet-Draft                YANG for NTP                 December 2018


   Note: The RFC Editor will replace YYYY with the number assigned to
   this document once it becomes an RFC.

10.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].

   The NETCONF access control model [RFC8341] provides the means to
   restrict access for particular NETCONF or RESTCONF users to a
   preconfigured subset of all available NETCONF or RESTCONF protocol
   operations and content.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

      /ntp/port - This data node specify the port number to be used to
      send NTP packets.  Unexpected changes could lead to disruption
      and/or network misbehavior.

      /ntp/authentication and /ntp/access-rules - The entries in the
      list include the authentication and access control configurations.
      Care should be taken while setting these parameters.

      /ntp/unicast-configuration - The entries in the list include all
      unicast configurations (server or peer mode), and indirectly
      creates or modify the NTP associations.  Unexpected changes could
      lead to disruption and/or network misbehavior.

      /ntp/interfaces/interface - The entries in the list inclide all
      per-interface configurations related to broadcast, multicast and
      manycast mode, and indirectly creates or modify the NTP
      associations.  Unexpected changes could lead to disruption and/or
      network misbehavior.

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or



Wu, et al.                Expires June 20, 2019                [Page 47]


Internet-Draft                YANG for NTP                 December 2018


   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

      /ntp/associations - The entries in the list includes all active
      NTP associations of all modes.  Unauthorized access to this needs
      to be curtailed.

11.  Acknowledgments

   The authors would like to express their thanks to Sladjana Zoric,
   Danny Mayer, Harlan Stenn, Ulrich Windl, Miroslav Lichvar, and
   Maurice Angermann for their review and suggestions.

12.  References

12.1.  Normative References

   [I-D.ietf-netmod-acl-model]
              Jethanandani, M., Agarwal, S., Huang, L., and D. Blair,
              "Network Access Control List (ACL) YANG Data Model",
              draft-ietf-netmod-acl-model-21 (work in progress),
              November 2018.

   [RFC1305]  Mills, D., "Network Time Protocol (Version 3)
              Specification, Implementation and Analysis", RFC 1305,
              DOI 10.17487/RFC1305, March 1992,
              <https://www.rfc-editor.org/info/rfc1305>.

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

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

   [RFC5905]  Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
              "Network Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
              <https://www.rfc-editor.org/info/rfc5905>.

   [RFC5907]  Gerstung, H., Elliott, C., and B. Haberman, Ed.,
              "Definitions of Managed Objects for Network Time Protocol
              Version 4 (NTPv4)", RFC 5907, DOI 10.17487/RFC5907, June
              2010, <https://www.rfc-editor.org/info/rfc5907>.





Wu, et al.                Expires June 20, 2019                [Page 48]


Internet-Draft                YANG for NTP                 December 2018


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

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

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

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8177]  Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J.
              Zhang, "YANG Data Model for Key Chains", RFC 8177,
              DOI 10.17487/RFC8177, June 2017,
              <https://www.rfc-editor.org/info/rfc8177>.

   [RFC8294]  Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger,
              "Common YANG Data Types for the Routing Area", RFC 8294,
              DOI 10.17487/RFC8294, December 2017,
              <https://www.rfc-editor.org/info/rfc8294>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.



Wu, et al.                Expires June 20, 2019                [Page 49]


Internet-Draft                YANG for NTP                 December 2018


   [RFC8343]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
              <https://www.rfc-editor.org/info/rfc8343>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

12.2.  Informative References

   [RFC7317]  Bierman, A. and M. Bjorklund, "A YANG Data Model for
              System Management", RFC 7317, DOI 10.17487/RFC7317, August
              2014, <https://www.rfc-editor.org/info/rfc7317>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

Authors' Addresses

   Nan Wu
   Huawei
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: eric.wu@huawei.com


   Dhruv Dhody
   Huawei
   Divyashree Techno Park, Whitefield
   Bangalore, Kanataka  560066
   India

   Email: dhruv.ietf@gmail.com


   Ankit kumar Sinha
   RtBrick Inc.
   Bangalore, Kanataka
   India

   Email: ankit.ietf@gmail.com






Wu, et al.                Expires June 20, 2019                [Page 50]


Internet-Draft                YANG for NTP                 December 2018


   Anil Kumar S N
   RtBrick Inc.
   Bangalore, Kanataka
   India

   Email: anil.ietf@gmail.com


   Yi Zhao
   Ericsson
   China Digital Kingdom Bld., No.1 WangJing North Rd.
   Beijing  100102
   China

   Email: yi.z.zhao@ericsson.com




































Wu, et al.                Expires June 20, 2019                [Page 51]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/