NTP Working Group
Internet Engineering Task Force (IETF) N. Wu
Internet-Draft
Request for Comments: 9249 D. Dhody, Ed.
Intended status:
Category: Standards Track Huawei
Expires: 21 September 2022
ISSN: 2070-1721 A. Sinha, Ed.
A. Kumar S N
RtBrick Inc.
Y. Zhao
Ericsson
20 March
June 2022
A YANG Data Model for NTP
draft-ietf-ntp-yang-data-model-17
Abstract
This document defines a YANG data model for implementations of the
Network Time Protocol (NTP) version 4 implementations. 4. It can also be used to
configure version 3. 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 an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of six months this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained 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 21 September 2022.
https://www.rfc-editor.org/info/rfc9249.
Copyright Notice
Copyright (c) 2022 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)
(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 Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised 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
1.5. References in the Model . . . . . . . . . . . . . . . . . 4
1.6. Requirements Language
2. NTP data model . . . . . . . . . . . . . . . . . . . . . . . 5 Data Model
3. Relationship with NTPv4-MIB . . . . . . . . . . . . . . . . . 7
4. Relationship with RFC 7317 . . . . . . . . . . . . . . . . . 9
5. Access Rules . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Key Management . . . . . . . . . . . . . . . . . . . . . . . 10
7. NTP Version . . . . . . . . . . . . . . . . . . . . . . . . . 10
8. NTP YANG Module . . . . . . . . . . . . . . . . . . . . . . . 11
9. Usage Example . . . . . . . . . . . . . . . . . . . . . . . . 41
9.1. Unicast association . . . . . . . . . . . . . . . . . . . 41 Association
9.2. Refclock master . . . . . . . . . . . . . . . . . . . . . 44 Master
9.3. Authentication configuration . . . . . . . . . . . . . . 44 Configuration
9.4. Access configuration . . . . . . . . . . . . . . . . . . 45 Configuration
9.5. Multicast configuration . . . . . . . . . . . . . . . . . 46 Configuration
9.6. Manycast configuration . . . . . . . . . . . . . . . . . 50 Configuration
9.7. Clock state . . . . . . . . . . . . . . . . . . . . . . . 53 State
9.8. Get all association . . . . . . . . . . . . . . . . . . . 53 All Association
9.9. Global statistic . . . . . . . . . . . . . . . . . . . . 55 Statistic
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 55
10.1. IETF XML Registry . . . . . . . . . . . . . . . . . . . 55
10.2. YANG Module Names . . . . . . . . . . . . . . . . . . . 55
11. Security Considerations . . . . . . . . . . . . . . . . . . . 56
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 57
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 58
13.1.
12.1. Normative References . . . . . . . . . . . . . . . . . . 58
13.2.
12.2. Informative References . . . . . . . . . . . . . . . . . 59
Appendix A. Full YANG Tree . . . . . . . . . . . . . . . . . . . 60
Acknowledgments
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 64
1. Introduction
This document defines a YANG [RFC7950] data model [RFC7950] for implementations
of the Network Time Protocol [RFC5905] implementations. version 4 [RFC5905]. Note that the
model could also be used to configure NTPv3 [RFC1305] (see
Section 7).
The data model covers configuration of system parameters of NTP, NTP such
as access rules, authentication and VPN Routing and Forwarding (VRF)
binding, and also various modes of NTP and per-interface parameters. It
also provides access to information about running state of NTP
implementations.
1.1. Operational State
NTP Operational State operational state is included in the same tree as NTP
configuration, consistent with Network "Network Management Datastore
Architecture (NMDA) (NMDA)" [RFC8342]. NTP current state and statistics are
also maintained in the operational state. The operational state also
includes the NTP association state.
1.2. Terminology
The terminology used in this document is aligned to with [RFC5905] and
[RFC1305].
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.
+==========+==========================+===========+
| Prefix | YANG module Module | Reference |
+==========+==========================+===========+
| yang | ietf-yang-types | [RFC6991] |
+----------+--------------------------+-----------+
| inet | ietf-inet-types | [RFC6991] |
+----------+--------------------------+-----------+
| if | ietf-interfaces | [RFC8343] |
+----------+--------------------------+-----------+
| sys | ietf-system | [RFC7317] |
+----------+--------------------------+-----------+
| acl | ietf-access-control-list | [RFC8519] |
+----------+--------------------------+-----------+
| rt-types | ietf-routing-types | [RFC8294] |
+----------+--------------------------+-----------+
| nacm | ietf-netconf-acm | [RFC8341] |
+----------+--------------------------+-----------+
Table 1: Prefixes and corresponding Corresponding YANG modules Modules
1.5. References in the Model
Following
The following documents are referenced in the model defined in this
document -
document.
+=======================================+===========+
| Title | Reference |
+=======================================+===========+
| Network Time Protocol Version 4: | [RFC5905] |
| Protocol and Algorithms Specification | |
+---------------------------------------+-----------+
| Common YANG Data Types | [RFC6991] |
+---------------------------------------+-----------+
| A YANG Data Model for System | [RFC7317] |
| Management | |
+---------------------------------------+-----------+
| Common YANG Data Types for the | [RFC8294] |
| Routing Area | |
+---------------------------------------+-----------+
| Network Configuration Access Control | [RFC8341] |
| Model | |
+---------------------------------------+-----------+
| A YANG Data Model for Interface | [RFC8343] |
| Management | |
+---------------------------------------+-----------+
| YANG Data Model for Network Access | [RFC8519] |
| Control Lists (ACLs) | |
+---------------------------------------+-----------+
| Message Authentication Code for the | [RFC8573] |
| Network Time Protocol | |
+---------------------------------------+-----------+
| The AES-CMAC Algorithm | [RFC4493] |
+---------------------------------------+-----------+
| The MD5 Message-Digest Algorithm | [RFC1321] |
+---------------------------------------+-----------+
| US Secure Hash Algorithm 1 (SHA1) | [RFC3174] |
+---------------------------------------+-----------+
| FIPS 180-4: Secure Hash Standard | [SHS] |
| (SHS) | |
+---------------------------------------+-----------+
Table 2: References in the YANG modules Module
1.6. 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.
2. NTP data model Data Model
This document defines the YANG module "ietf-ntp", which has the
following condensed structure:
module: ietf-ntp
+--rw ntp!
+--rw port? inet:port-number {ntp-port}?
+--rw refclock-master!
| +--rw master-stratum? ntp-stratum
+--rw authentication {authentication}?
| +--rw auth-enabled? boolean
| +--rw authentication-keys* [key-id]
| +--rw key-id uint32
| +--...
+--rw access-rules {access-rules}?
| +--rw access-rule* [access-mode]
| +--rw access-mode identityref
| +--rw acl? -> /acl:acls/acl/name
+--ro clock-state
| +--ro system-status
| +--ro clock-state identityref
| +--ro clock-stratum ntp-stratum
| +--ro clock-refid refid
| +--...
+--rw unicast-configuration* [address type]
| {unicast-configuration}?
| +--rw address inet:ip-address
| +--rw type identityref
| +--...
+--rw associations
| +--ro association* [address local-mode isconfigured]
| +--ro address inet:ip-address
| +--ro local-mode identityref
| +--ro isconfigured boolean
| +--...
| +--ro ntp-statistics
| +--...
+--rw interfaces
| +--rw interface* [name]
| +--rw name if:interface-ref
| +--rw broadcast-server! {broadcast-server}?
| | +--...
| +--rw broadcast-client! {broadcast-client}?
| +--rw multicast-server* [address] {multicast-server}?
| | +--rw address
| | | rt-types:ip-multicast-group-address
| | +--...
| +--rw multicast-client* [address] {multicast-client}?
| | +--rw address rt-types:ip-multicast-group-address
| +--rw manycast-server* [address] {manycast-server}?
| | +--rw address rt-types:ip-multicast-group-address
| +--rw manycast-client* [address] {manycast-client}?
| +--rw address
| | rt-types:ip-multicast-group-address
| +--...
+--ro ntp-statistics
+--...
rpcs:
+---x statistics-reset
+---w input
+---w (association-or-all)?
+--:(association)
| +---w associations-address?
| | -> /ntp/associations/association/address
| +---w associations-local-mode?
| | -> /ntp/associations/association/local-mode
| +---w associations-isconfigured?
| -> /ntp/associations/association/isconfigured
+--:(all)
The full data model tree for the YANG module "ietf-ntp" is in
Appendix A.
This data model defines one top-level container which that includes both
the NTP configuration and the NTP running state including access
rules, authentication, associations, unicast configurations,
interfaces, system status status, and associations.
3. Relationship with NTPv4-MIB
If the device implements the NTPv4-MIB [RFC5907], data nodes from the
YANG module can be mapped to table entries in the 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 Data Nodes in /ntp/ | NTPv4-MIB objects Objects |
| clock-state/system-status | |
+===========================+=================================+
| clock-state | ntpEntStatusCurrentMode |
+---------------------------+---------------------------------+
| clock-stratum | ntpEntStatusStratum |
+---------------------------+---------------------------------+
| clock-refid | ntpEntStatusActiveRefSourceId |
+---------------------------+---------------------------------+
| | ntpEntStatusActiveRefSourceName |
+---------------------------+---------------------------------+
| clock-precision | ntpEntTimePrecision |
+---------------------------+---------------------------------+
| clock-offset | ntpEntStatusActiveOffset |
+---------------------------+---------------------------------+
| root-dispersion | ntpEntStatusDispersion |
+---------------------------+---------------------------------+
Table 3 3: YANG NTP Data Nodes in /ntp/clock-state/system-
status and Related NTPv4-MIB Objects
+=======================================+===========================+
| YANG data nodes Data Nodes in | NTPv4-MIB objects Objects |
| /ntp/associations/ | |
+=======================================+===========================+
| address | ntpAssocAddressType |
+---------------------------------------+---------------------------+
| | ntpAssocAddress |
+---------------------------------------+---------------------------+
| stratum | ntpAssocStratum |
+---------------------------------------+---------------------------+
| refid | ntpAssocRefId |
+---------------------------------------+---------------------------+
| offset | ntpAssocOffset |
+---------------------------------------+---------------------------+
| delay | ntpAssocStatusDelay |
+---------------------------------------+---------------------------+
| dispersion | ntpAssocStatusDispersion |
+---------------------------------------+---------------------------+
| ntp-statistics/ | ntpAssocStatOutPkts |
| packet-sent | |
+---------------------------------------+---------------------------+
| ntp-statistics/ | ntpAssocStatInPkts |
| packet-received | |
+---------------------------------------+---------------------------+
| ntp-statistics/ | ntpAssocStatProtocolError |
| packet-dropped | |
+---------------------------------------+---------------------------+
Table 4 4: YANG NTP State Data Nodes in /ntp/associations/ and Related
NTPv4-MIB Objects
4. Relationship with RFC 7317
This section describes the relationship with NTP definition of NTP in
Section 3.2 System (System Time Management Management) of [RFC7317] . [RFC7317]. YANG data nodes
in /ntp/ also support per-interface configuration configuration, which is not
supported in /system/ntp. If the yang YANG data model defined in this
document is implemented, then /system/ntp SHOULD NOT be used and MUST
be ignored.
+===============================+================================+
| YANG data nodes Data Nodes in /ntp/ | YANG data nodes 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 |
+-------------------------------+--------------------------------+
Table 5 5: YANG NTP Configuration Data Nodes and counterparts in Counterparts
from RFC 7317
Objects
5. Access Rules
The access rules in this section refers to the on-the-wire access
control to the NTP service and completely independent of any
management API access control, e.g., NETCONF Access Control Model
(NACM) ([RFC8341]). [RFC8341].
An Access Control List (ACL) is one of the basic elements used to
configure device-forwarding behavior. An ACL is a user-ordered set
of rules that is used to filter traffic on a networking device.
As per [RFC1305] (for NTPv3) and [RFC5905] (for NTPv4), NTP could
include an access-control feature that prevents unauthorized access
and that controls which peers are allowed to update the local clock.
Further
Further, it is useful to differentiate between the various kinds of
access and attach a different acl-rule to each. For this, the YANG
module allows such configuration via /ntp/access-rules. The access-
rule itself is configured via [RFC8519].
Following
The following access modes are supported -
* supported:
Peer: Permit others to synchronize their time with the NTP entity or
it can synchronize its time with others. NTP control queries are
also accepted.
*
Server: Permit others to synchronize their time with the NTP entity,
but vice versa is not supported. NTP control queries are
accepted.
*
Server-only: Permit others to synchronize their time with the NTP
entity, but vice versa is not supported. NTP control queries are
not accepted.
*
Query-only: Only control queries are accepted.
Query-only is the most restricted where as whereas the peer is the full access
authority. The ability to give different ACL rules for different
access modes allows for a greater control by the operator.
6. Key Management
As per [RFC1305] (for NTPv3) and [RFC5905] (for NTPv4), 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 a 32-bit
unsigned integer that MUST be configured on the NTP peers before the
authentication could can be used. For this reason, this YANG module allows
such configuration via /ntp/authentication/authentication-
keys/. /ntp/authentication/authentication-keys/.
Further at the time of configuration of NTP association (for
example example,
unicast-server), the key-id is specified.
The 'nacm:default-deny-all' is used to prevent retrieval of the
actual key information after it is set.
7. NTP Version
This YANG data model allow allows a version to be configured for the NTP
association i.e.
association, i.e., an operator can control the use of NTPv3 [RFC1305]
or NTPv4 [RFC5905] for each association it forms. This allows
backward compatibility with a legacy system. Note that the version 3
of NTP NTPv3
[RFC1305] is obsoleted by NTPv4 [RFC5905].
8. NTP YANG Module
<CODE BEGINS> file "ietf-ntp@2022-03-21.yang" "ietf-ntp@2022-06-10.yang"
module ietf-ntp {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ntp";
prefix ntp;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-interfaces {
prefix if;
reference
"RFC 8343: A YANG Data Model for Interface Management";
}
import ietf-system {
prefix sys;
reference
"RFC 7317: A YANG Data Model for System Management";
}
import ietf-access-control-list {
prefix acl;
reference
"RFC 8519: YANG Data Model for Network Access Control
Lists (ACLs)";
}
import ietf-routing-types {
prefix rt-types;
reference
"RFC 8294: Common YANG Data Types for the Routing Area";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Protocol (NETCONF) Access Control Model";
}
organization
"IETF NTP (Network Time Protocol) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/ntp/about/> <https://datatracker.ietf.org/wg/ntp/>
WG List: <mailto: ntp@ietf.org
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 implementations of
the Network Time Protocol
(NTP) implementations. (NTP). The data model includes
configuration data and state data.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.
Copyright (c) 2022 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 Revised BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; 9249; see the
RFC itself for full legal notices.";
revision 2022-03-21 2022-06-10 {
description
"Initial revision."; revision";
reference
"RFC XXXX: 9249: A YANG Data Model for NTP."; NTP";
}
/* Note: The RFC Editor will replace XXXX 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"; level.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
typedef ntp-version {
type uint8 {
range "3..max";
}
default "4";
description
"The current NTP version supported by the corresponding
association.";
association";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 1";
}
typedef refid {
type union {
type inet:ipv4-address;
type uint32;
type string {
length "4";
}
}
description
"A code identifying the particular server or reference
clock. The interpretation depends upon stratum. It
could be an IPv4 address or address, the first 32 bits of the MD5 hash
of the IPv6 address address, or a string for the Reference Identifier
and KISS codes. Some examples:
-- a refclock ID like '127.127.1.0' for local clock sync
-- uni/multi/broadcast associations for IPv4 will look like
'203.0.113.1' and '0x4321FEDC' for IPv6
-- sync with a primary source will look like 'DCN', 'NIST',
'ATOM'
-- KISS codes will look like 'AUTH', 'DROP', or 'RATE'
Note that the use of an MD5 hash for IPv6 address addresses is not
for cryptographic purposes "; purposes.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
typedef ntp-date-and-time {
type union {
type yang:date-and-time;
type uint8;
}
description
"Follows the date-and-time format when valid value exist,
otherwise values exist.
Otherwise, allows for setting a special value such as
zero.";
reference
"RFC 6991: Common YANG Data Types";
}
typedef log2seconds {
type int8;
description
"An 8-bit signed integer that represents signed log2
seconds.";
}
/* features */
feature ntp-port {
description
"Support for NTP port configuration";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.2";
}
feature authentication {
description
"Support for NTP symmetric key authentication";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
feature deprecated {
description
"Support deprecated MD5-based authentication (RFC 8573) or
SHA-1 8573),
SHA-1, or any other deprecated authentication mechanism.
It is enabled to support legacy compatibility when secure
cryptographic algorithms are not available to use.
It is also used to configure keystrings in ASCII format.";
reference
"RFC 1321: The MD5 Message-Digest Algorithm Algorithm,
RFC 3174: US Secure Hash Algorithm 1 (SHA1) (SHA1),
FIPS 180-4: Secure Hash Standard (SHS)";
}
feature hex-key-string {
description
"Support hexadecimal key string."; string";
}
feature access-rules {
description
"Support for NTP access control";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 9.2";
}
feature unicast-configuration {
description
"Support for NTP client/server or active/passive
in unicast";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
feature broadcast-server {
description
"Support for broadcast server";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
feature broadcast-client {
description
"Support for broadcast client";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
feature multicast-server {
description
"Support for multicast server";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3.1";
}
feature multicast-client {
description
"Support for multicast client";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3.1";
}
feature manycast-server {
description
"Support for manycast server";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3.1";
}
feature manycast-client {
description
"Support for manycast client";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3.1";
}
/* Identity */
/* unicast-configurations types */
identity unicast-configuration-type {
if-feature "unicast-configuration";
description
"This defines NTP unicast mode of operation as used
for unicast-configurations.";
}
identity uc-server {
if-feature "unicast-configuration";
base unicast-configuration-type;
description
"Use client association mode where the unicast server
address is configured.";
}
identity uc-peer {
if-feature "unicast-configuration";
base unicast-configuration-type;
description
"Use symmetric active association mode where the peer
address is configured.";
}
/* association-modes */
identity association-mode {
description
"The NTP association modes."; modes";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
identity active {
base association-mode;
description
"Use symmetric active association mode (mode 1).
This device may synchronize with its NTP peer, peer
or provide synchronization to a configured NTP peer.";
}
identity passive {
base association-mode;
description
"Use symmetric passive association mode (mode 2).
This device has learned this association dynamically.
This device may synchronize with its NTP peer.";
}
identity client {
base association-mode;
description
"Use client association mode (mode 3).
This device will not provide synchronization
to the configured NTP server.";
}
identity server {
base association-mode;
description
"Use server association mode (mode 4).
This device will provide synchronization to
NTP clients.";
}
identity broadcast-server {
base association-mode;
description
"Use broadcast server mode (mode 5).
This mode defines that its it's either working
as a broadcast-server or a multicast-server.";
}
identity broadcast-client {
base association-mode;
description
"This mode defines that its it's either working
as a broadcast-client (mode 6) or a multicast-client.";
}
/* access-mode */
identity access-mode {
if-feature "access-rules";
description
"This defines NTP access modes. These identify
how the ACL is applied with NTP.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 9.2";
}
identity peer-access-mode {
if-feature "access-rules";
base access-mode;
description
"Permit others to synchronize their time with this NTP
entity or it can synchronize its time with others.
NTP control queries are also accepted. This enables
full access authority.";
}
identity server-access-mode {
if-feature "access-rules";
base access-mode;
description
"Permit others to synchronize their time with this NTP
entity, but vice versa is not supported. NTP control
queries are accepted.";
}
identity server-only-access-mode {
if-feature "access-rules";
base access-mode;
description
"Permit others to synchronize their time with this NTP
entity, but vice versa is not supported. NTP control
queries are not accepted.";
}
identity query-only-access-mode {
if-feature "access-rules";
base access-mode;
description
"Only control queries are accepted.";
}
/* clock-state */
identity clock-state {
description
"This defines NTP clock status at a high level.";
}
identity synchronized {
base clock-state;
description
"Indicates that the local clock has been synchronized with
an NTP server or the reference clock.";
}
identity unsynchronized {
base clock-state;
description
"Indicates that the local clock has not been synchronized
with any NTP server.";
}
/* ntp-sync-state */
identity ntp-sync-state {
description
"This defines NTP clock sync state at a more granular
level. Referred to as 'Clock state definitions' in
RFC 5905"; 5905.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Appendix A.1.1";
}
identity clock-never-set {
base ntp-sync-state;
description
"Indicates the clock was never set.";
}
identity freq-set-by-cfg {
base ntp-sync-state;
description
"Indicates the clock frequency is set by
NTP configuration or file.";
}
identity spike {
base ntp-sync-state;
description
"Indicates a spike is detected.";
}
identity freq {
base ntp-sync-state;
description
"Indicates the frequency mode.";
}
identity clock-synchronized {
base ntp-sync-state;
description
"Indicates that the clock is synchronized"; synchronized.";
}
/* crypto-algorithm */
identity crypto-algorithm {
description
"Base identity of cryptographic algorithm options.";
}
identity md5 {
if-feature "deprecated";
base crypto-algorithm;
description
"The MD5 algorithm. Note that RFC 8573
deprecates the use of MD5-based authentication.";
reference
"RFC 1321: The MD5 Message-Digest Algorithm";
}
identity sha-1 {
if-feature "deprecated";
base crypto-algorithm;
description
"The SHA-1 algorithm."; algorithm";
reference
"RFC 3174: US Secure Hash Algorithm 1 (SHA1)";
}
identity hmac-sha-1 {
if-feature "deprecated";
base crypto-algorithm;
description
"HMAC-SHA-1 authentication algorithm."; algorithm";
reference
"FIPS 180-4: Secure Hash Standard (SHS)";
}
identity hmac-sha1-12 {
if-feature "deprecated";
base crypto-algorithm;
description
"The HMAC-SHA1-12 algorithm."; algorithm";
}
identity hmac-sha-256 {
description
"HMAC-SHA-256 authentication algorithm."; algorithm";
reference
"FIPS 180-4: Secure Hash Standard (SHS)";
}
identity hmac-sha-384 {
description
"HMAC-SHA-384 authentication algorithm."; algorithm";
reference
"FIPS 180-4: Secure Hash Standard (SHS)";
}
identity hmac-sha-512 {
description
"HMAC-SHA-512 authentication algorithm."; algorithm";
reference
"FIPS 180-4: Secure Hash Standard (SHS)";
}
identity aes-cmac {
base crypto-algorithm;
description
"The AES-CMAC algorithm - -- required by
RFC 8573 for MAC for the NTP"; NTP.";
reference
"RFC 4493: The AES-CMAC Algorithm Algorithm,
RFC 8573: Message Authentication Code for the Network
Time Protocol";
}
/* Groupings */
grouping key {
description
"The key."; key";
nacm:default-deny-all;
choice key-string-style {
description
"Key string styles";
case keystring {
leaf keystring {
if-feature "deprecated";
type string;
description
"Key string in ASCII format."; format";
}
}
case hexadecimal {
if-feature "hex-key-string";
leaf hexadecimal-string {
type yang:hex-string;
description
"Key in hexadecimal string format. When compared
to ASCII, specification in hexadecimal affords
greater key entropy with the same number of
internal key-string octets. Additionally, it
discourages usage use of well-known words or
numbers.";
}
}
}
}
grouping authentication-key {
description
"To define an authentication key for a Network Time
Protocol (NTP) an NTP
time source.";
leaf key-id {
type uint32 {
range "1..max";
}
description
"Authentication key identifier."; identifier";
}
leaf algorithm {
type identityref {
base crypto-algorithm;
}
description
"Authentication algorithm. Note that RFC 8573
deprecates the use of MD5-based authentication
and recommends AES-CMAC.";
}
container key {
uses key;
description
"The key. Note that RFC 8573 deprecates the use
of MD5-based authentication.";
}
leaf istrusted {
type boolean;
description
"Key-id is trusted or not";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section Sections 7.3 and 7.4";
}
grouping authentication {
description
"Authentication.";
"Authentication";
choice authentication-type {
description
"Type of authentication."; authentication";
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."; statistic";
leaf discontinuity-time {
type ntp-date-and-time;
description
"The time on the most recent occasion at which any one or
more of this these NTP counters suffered a discontinuity. If
no such discontinuities have occurred, then this node
contains the time the NTP association was
(re-)initialized.";
}
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.
Discontinuities in the value of this counter can occur
upon cold start or reinitialization of the NTP entity, the
management system and at other times.";
}
leaf packet-sent-fail {
type yang:counter32;
description
"The number of times NTP packets packet sending failed.";
}
leaf packet-received {
type yang:counter32;
description
"The total number of NTP packets delivered to the
NTP entity from this association.
Discontinuities in the value of this counter can occur
upon cold start or reinitialization of the NTP entity, the
management system and at other times.";
}
leaf packet-dropped {
type yang:counter32;
description
"The total number of NTP packets that were delivered
to this NTP entity from this association and that this
entity was not able to process due to an NTP protocol error.
Discontinuities in the value of this counter can occur
upon cold start or reinitialization of the NTP entity, entity or the
management system and at other times.";
}
}
grouping common-attributes {
description
"NTP common attributes for configuration."; configuration";
leaf minpoll {
type log2seconds;
default "6";
description
"The minimum poll interval used in this association."; association";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.2";
}
leaf maxpoll {
type log2seconds;
default "10";
description
"The maximum poll interval used in this association."; association";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.2";
}
leaf port {
if-feature "ntp-port";
type inet:port-number {
range "123 | 1024..max";
}
default "123";
description
"Specify the port used to send NTP packets.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.2";
}
leaf version {
type ntp-version;
description
"NTP version."; version";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification";
}
grouping association-ref {
description
"Reference to NTP association mode";
leaf associations-address {
type leafref {
path "/ntp:ntp/ntp:associations/ntp:association"
+ "/ntp:address";
}
description
"Indicates the association's address
which result
that results in clock synchronization.";
}
leaf associations-local-mode {
type leafref {
path "/ntp:ntp/ntp:associations/ntp:association"
+ "/ntp:local-mode";
}
description
"Indicates the association's local-mode
which result
that results in clock synchronization.";
}
leaf associations-isconfigured {
type leafref {
path "/ntp:ntp/ntp:associations/ntp:association/"
+ "ntp:isconfigured";
}
description
"Indicates if the association (that resulted in the
clock synchronization) is explicitly configured.";
}
}
container ntp {
when 'false() = boolean(/sys:system/sys:ntp)' {
description
"Applicable when the system /sys/ntp/ is not used.";
}
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."; NTP";
leaf port {
if-feature "ntp-port";
type inet:port-number {
range "123 | 1024..max";
}
default "123";
description
"Specify the port used to send and receive NTP packets.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.2";
}
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.";
}
}
container authentication {
if-feature "authentication";
description
"Configuration of authentication."; 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."; keys";
}
}
container access-rules {
if-feature "access-rules";
description
"Configuration to control access to NTP service
by using the 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."; rules";
leaf access-mode {
type identityref {
base access-mode;
}
description
"The NTP access mode. Some of the possible value
includes values
include peer, server, synchronization, query query,
etc.";
}
leaf acl {
type leafref {
path "/acl:acls/acl:acl/acl:name";
}
description
"Control access configuration to be used.";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 9.2";
}
}
container clock-state {
config false;
description
"Clock operational state of the NTP."; NTP";
container system-status {
description
"System status of NTP."; NTP";
leaf clock-state {
type identityref {
base clock-state;
}
mandatory true;
description
"The state of the system clock. Some of the possible value
includes
values include synchronized and unsynchronized"; unsynchronized.";
}
leaf clock-stratum {
type ntp-stratum;
mandatory true;
description
"The NTP entity's own stratum value. Should be one
greater than preceeding the preceding level.
16 if unsyncronized."; unsynchronized.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
leaf clock-refid {
type refid;
mandatory true;
description
"A code identifying the particular server or reference
clock. The interpretation depends upon stratum. It
could be an IPv4 address or address, the first 32 bits of the MD5
hash of the IPv6 address address, or a string for the Reference
Identifier and KISS codes. Some examples:
-- a refclock ID like '127.127.1.0' for local clock sync
-- uni/multi/broadcast associations for IPv4 will look
like '203.0.113.1' and '0x4321FEDC' for IPv6
-- sync with primary source will look like 'DCN',
'NIST', 'ATOM'
-- KISS codes will look like 'AUTH', 'DROP', 'RATE'
Note that the use of MD5 hash for IPv6 address is not
for cryptographic purposes "; purposes.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
uses association-ref {
description
"Reference to Association."; Association";
}
leaf nominal-freq {
type decimal64 {
fraction-digits 4;
}
units "Hz";
mandatory true;
description
"The nominal frequency of the local clock. An ideal
frequency with zero uncertainty.";
}
leaf actual-freq {
type decimal64 {
fraction-digits 4;
}
units "Hz";
mandatory true;
description
"The actual frequency of the local clock."; clock";
}
leaf clock-precision {
type log2seconds;
mandatory true;
description
"Clock precision of this system in signed integer format,
in log 2 seconds - (prec=2^(-n)). A value of 5 would
mean 2^-5 = 0.03125 seconds = 31.25 ms.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
leaf clock-offset {
type decimal64 {
fraction-digits 3;
}
units "milliseconds";
description
"The signed time offset to the current selected reference
time source source, e.g., '0.032ms' or '1.232ms'. The negative
value Indicates indicates that the local clock is behind the
current selected reference time source.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 9.1";
}
leaf root-delay {
type decimal64 {
fraction-digits 3;
}
units "milliseconds";
description
"Total delay along the path to the root clock."; clock";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section Sections 4 and 7.3";
}
leaf root-dispersion {
type decimal64 {
fraction-digits 3;
}
units "milliseconds";
description
"The dispersion between the local clock
and the root clock, e.g., '6.927ms'.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section Sections 4, 7.3 7.3, and 10."; 10";
}
leaf reference-time {
type ntp-date-and-time;
description
"The reference timestamp. Time when the system clock was
last set or corrected"; corrected.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
leaf sync-state {
type identityref {
base ntp-sync-state;
}
mandatory true;
description
"The synchronization status of the local clock. Referred
to as 'Clock state definitions' in RFC 5905"; 5905.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Appendix A.1.1";
}
}
}
list unicast-configuration {
if-feature "unicast-configuration";
key "address type";
description
"List of NTP unicast-configurations."; unicast-configurations";
leaf address {
type inet:ip-address;
description
"Address of this association."; association";
}
leaf type {
type identityref {
base unicast-configuration-type;
}
description
"The unicast configuration type, for example example,
unicast-server";
}
container authentication {
if-feature "authentication";
description
"Authentication used for this association."; association";
uses authentication;
}
leaf prefer {
type boolean;
default "false";
description
"Whether or not this association is preferred or not."; preferred";
}
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.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 13.1";
}
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.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 13.1";
}
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, and min and max
poll.";
}
}
container associations {
description
"Association parameters";
list association {
key "address local-mode isconfigured";
config false;
description
"List of NTP associations. Here address, local-mode local-mode,
and isconfigured are required to uniquely identify
a particular association. Lets Let's take the following examples -
examples:
1) If RT1 is acting as broadcast server, server
and RT2 is acting as broadcast client, then RT2
will form a dynamic association with the address as
RT1, local-mode as client client, and isconfigured as false.
2) When RT2 is configured with unicast-server RT1,
then RT2 will form an association with the address as
RT1, local-mode as client client, and isconfigured as true.
Thus
Thus, all 3 three leaves are needed as key to unique uniquely
identify the association.";
leaf address {
type inet:ip-address;
description
"The remote address of this association. Represents the
IP address of a unicast/multicast/broadcast address.";
}
leaf local-mode {
type identityref {
base association-mode;
}
description
"Local mode of this NTP association."; association";
}
leaf isconfigured {
type boolean;
description
"Indicates if this association is configured (true) or
dynamically learned (false).";
}
leaf stratum {
type ntp-stratum;
description
"The association stratum value."; value";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 3";
}
leaf refid {
type refid;
description
"A code identifying the particular server or reference
clock. The interpretation depends upon stratum. It
could be an IPv4 address or first 32 bits of the MD5
hash of the IPv6 address or a string for the Reference
Identifier and KISS codes. Some examples:
-- a refclock ID like '127.127.1.0' for local clock sync
-- uni/multi/broadcast associations for IPv4 will look
like '203.0.113.1' and '0x4321FEDC' for IPv6
-- sync with primary source will look like 'DCN',
'NIST', or 'ATOM'
-- KISS codes will look like 'AUTH', 'DROP', or 'RATE'
Note that the use of an MD5 hash for IPv6 address is
not for cryptographic purposes"; purposes.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
leaf authentication {
if-feature "authentication";
type leafref {
path "/ntp:ntp/ntp:authentication/"
+ "ntp:authentication-keys/ntp:key-id";
}
description
"Authentication Key used for this association."; association";
}
leaf prefer {
type boolean;
default "false";
description
"Indicates if this association is preferred."; preferred";
}
leaf peer-interface {
type if:interface-ref;
description
"The interface which that is used for communication."; communication";
}
uses common-attributes {
description
"Common attributes like port, version, and min and
max poll."; poll";
}
leaf reach {
type uint8;
description
"It is an
"An 8-bit shift register that tracks packet
generation and receipt. It is used to determine
whether the server is reachable and the data are
fresh.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section Sections 9.2 and 13";
}
leaf unreach {
type uint8;
units "seconds";
description
"It is a
"A count of how long in second the server has been
unreachable i.e.
unreachable, i.e., the reach value has been zero.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section Sections 9.2 and 13";
}
leaf poll {
type log2seconds;
description
"The polling interval for current association in signed
log2 seconds.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 7.3";
}
leaf now {
type uint32;
units "seconds";
description
"The time since the last NTP packet was
received or last synchronized.";
}
leaf offset {
type decimal64 {
fraction-digits 3;
}
units "milliseconds";
description
"The signed offset between the local clock
and the peer clock, e.g., '0.032ms' or '1.232ms'. The
negative value Indicates indicates that the local clock is behind
the peer.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 8";
}
leaf delay {
type decimal64 {
fraction-digits 3;
}
units "milliseconds";
description
"The network delay between the local clock
and the peer clock."; clock";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 8";
}
leaf dispersion {
type decimal64 {
fraction-digits 3;
}
units "milliseconds";
description
"The root dispersion between the local clock
and the peer clock.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 10";
}
leaf originate-time {
type ntp-date-and-time;
description
"This is the local time, in timestamp format,
when the latest NTP packet was sent to the peer
(called T1).";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol and
Algorithms Specification, Section 8";
}
leaf receive-time {
type ntp-date-and-time;
description
"This is the local time, in timestamp format,
when the latest NTP packet arrived at the peer
(called T2). If the peer becomes unreachable unreachable,
the value is set to zero.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 8";
}
leaf transmit-time {
type ntp-date-and-time;
description
"This is the local time, in timestamp format,
at which the NTP packet departed the peer
(called T3). If the peer becomes unreachable unreachable,
the value is set to zero.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 8";
}
leaf input-time {
type ntp-date-and-time;
description
"This is the local time, in timestamp format,
when the latest NTP message from the peer arrived
(called T4). If the peer becomes unreachable the unreachable,
value is set to zero.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 8";
}
container ntp-statistics {
description
"Per Peer packet send and receive statistics."; statistics";
uses statistics {
description
"NTP send and receive packet statistics."; statistics";
}
}
}
}
container interfaces {
description
"Configuration parameters for NTP interfaces."; interfaces";
list interface {
key "name";
description
"List of interfaces."; interfaces";
leaf name {
type if:interface-ref;
description
"The interface name."; name";
}
container broadcast-server {
if-feature "broadcast-server";
presence "NTP broadcast-server is configured on this
interface";
interface.";
description
"Configuration of broadcast server."; server";
leaf ttl {
type uint8;
description
"Specifies the time to live (TTL) for a
broadcast packet."; packet";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
container authentication {
if-feature "authentication";
description
"Authentication used on this interface."; interface";
uses authentication;
}
uses common-attributes {
description
"Common attributes such as port, version, and min and
max poll."; poll";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
container broadcast-client {
if-feature "broadcast-client";
presence "NTP broadcast-client is configured on this
interface.";
description
"Configuration of broadcast-client."; broadcast-client";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
list multicast-server {
if-feature "multicast-server";
key "address";
description
"Configuration of multicast server."; server";
leaf address {
type rt-types:ip-multicast-group-address;
description
"The IP address to send NTP multicast packets."; packets";
}
leaf ttl {
type uint8;
description
"Specifies the time to live (TTL) TTL for a multicast packet."; packet";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
container authentication {
if-feature "authentication";
description
"Authentication used on this interface."; interface";
uses authentication;
}
uses common-attributes {
description
"Common attributes such as port, version, and min and
max poll."; poll";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
list multicast-client {
if-feature "multicast-client";
key "address";
description
"Configuration of multicast-client."; a multicast-client";
leaf address {
type rt-types:ip-multicast-group-address;
description
"The IP address of the multicast group to
join.";
join";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
list manycast-server {
if-feature "manycast-server";
key "address";
description
"Configuration of a manycast server."; server";
leaf address {
type rt-types:ip-multicast-group-address;
description
"The multicast group IP address to receive
manycast client messages.";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
list manycast-client {
if-feature "manycast-client";
key "address";
description
"Configuration of manycast-client."; 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."; to";
}
container authentication {
if-feature "authentication";
description
"Authentication used on this interface."; interface";
uses authentication;
}
leaf ttl {
type uint8;
description
"Specifies the maximum time to live (TTL) TTL for the expanding
ring search."; search";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
leaf minclock {
type uint8;
description
"The minimum manycast survivors in this
association.";
association";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 13.2";
}
leaf maxclock {
type uint8;
description
"The maximum manycast candidates in this
association.";
association";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 13.2";
}
leaf beacon {
type log2seconds;
description
"The beacon is the upper limit of the poll interval.
When the
ttl TTL reaches its limit without finding the
minimum number of manycast servers, the poll interval
increases until reaching the beacon value, when it
starts over from the beginning.";
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 13.2";
}
uses common-attributes {
description
"Common attributes like port, version, and min and
max poll."; poll";
}
reference
"RFC 5905: Network Time Protocol Version 4: Protocol
and Algorithms Specification, Section 3.1";
}
}
}
container ntp-statistics {
config false;
description
"Total NTP packet statistics."; statistics";
uses statistics {
description
"NTP send and receive packet statistics."; statistics";
}
}
}
rpc statistics-reset {
description
"Reset statistics collected.";
input {
choice association-or-all {
description
"Resets statistics for a particular association or
all";
all.";
case association {
uses association-ref;
description
"This resets all the statistics collected for
the association.";
}
case all {
description
"This resets all the statistics collected.";
}
}
}
}
}
<CODE ENDS>
9. Usage Example
This section include examples for illustration purposes.
Note: '\' indicates line wrapping per [RFC8792].
9.1. Unicast association Association
This example describes how to configure a preferred unicast server
present at 192.0.2.1 running at port 1025 with authentication-key 10
and version 4 (default).
<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>uc-server</type>
<prefer>true</prefer>
<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 use an IPv6 address (say 2001:db8::1) in
the "address" leaf with no change in any other data tree.
<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>2001:db8::1</address>
<type>uc-server</type>
<prefer>true</prefer>
<port>1025</port>
<authentication>
<symmetric-key>
<key-id>10</key-id>
</symmetric-key>
</authentication>
</unicast-configuration>
</ntp>
</config>
</edit-config>
This example is for retrieving unicast configurations - configurations:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<unicast-configuration>
</unicast-configuration>
</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>uc-server</type>
<authentication>
<symmetric-key>
<key-id>10</key-id>
</symmetric-key>
</authentication>
<prefer>true</prefer>
<burst>false</burst>
<iburst>true</iburst>
<source/>
<minpoll>6</minpoll>
<maxpoll>10</maxpoll>
<port>1025</port>
<stratum>9</stratum>
<refid>203.0.113.1</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>
9.2. Refclock master Master
This example describes how to configure reference clock with stratum
8 -
8:
<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>
This example describes how to get reference clock configuration - configuration:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<refclock-master>
</refclock-master>
</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>
9.3. Authentication configuration Configuration
This example describes how to enable authentication and configure
trusted authentication key 10 with mode as AES-CMAC and an a hexadecimal
string key - key:
<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>aes-cmac</algorithm>
<key>
<hexadecimal-string>
bb1d6929e95937287fa37d129b756746
</hexadecimal-string>
</key>
<istrusted>true</istrusted>
</authentication-keys>
</authentication>
</ntp>
</config>
</edit-config>
9.4. Access configuration Configuration
This example describes how to configure access mode "peer" associated
with ACL 2000 - 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</access-mode>
<acl>2000</acl>
</access-rule>
</access-rules>
</ntp>
</config>
</edit-config>
This example describes how to get access related configuration - access-related configuration:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<access-rules>
</access-rules>
</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</access-mode>
<acl>2000</acl>
</access-rule>
</access-rules>
</ntp>
</data>
9.5. Multicast configuration Configuration
This example describes how to configure a multicast-server with an
address
as of "224.0.1.1", port as of 1025, and version as 3 of 3, and
authentication keyid as 10 - of 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>
<multicast-server>
<address>224.0.1.1</address>
<authentication>
<symmetric-key>
<key-id>10</key-id>
</symmetric-key>
</authentication>
<port>1025</port>
<version>3</version>
</multicast-server>
</interface>
</interfaces>
</ntp>
</config>
</edit-config>
This example describes how to get multicast-server related
configuration - multicast-server-related
configuration:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<interfaces>
<interface>
<multicast-server>
</multicast-server>
</interface>
</interfaces>
</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>224.0.1.1</address>
<ttl>8</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>
This example describes how to configure a multicast-client with an
address
as "224.0.1.1" - of "224.0.1.1":
<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>224.0.1.1</address>
</multicast-client>
</interface>
</interfaces>
</ntp>
</config>
</edit-config>
This example describes how to get multicast-client related
configuration - multicast-client-related
configuration:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<interfaces>
<interface>
<multicast-client>
</multicast-client>
</interface>
</interfaces>
</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>224.0.1.1</address>
</multicast-client>
</interface>
</interfaces>
</ntp>
</data>
9.6. Manycast configuration Configuration
This example describes how to configure a manycast-client with an
address
as of "224.0.1.1", port as 1025 of 1025, and authentication keyid as 10 - of 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>224.0.1.1</address>
<authentication>
<symmetric-key>
<key-id>10</key-id>
</symmetric-key>
</authentication>
<port>1025</port>
</manycast-client>
</interface>
</interfaces>
</ntp>
</config>
</edit-config>
This example describes how to get manycast-client related
configuration - manycast-client-related
configuration:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<interfaces>
<interface>
<manycast-client>
</manycast-client>
</interface>
</interfaces>
</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>224.0.1.1</address>
<authentication>
<symmetric-key>
<key-id>10</key-id>
</symmetric-key>
</authentication>
<ttl>8</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>
This example describes how to configure a manycast-server with an
address
as "224.0.1.1" - of "224.0.1.1":
<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>224.0.1.1</address>
</manycast-server>
</interface>
</interfaces>
</ntp>
</config>
</edit-config>
This example describes how to get manycast-server related
configuration - manycast-server-related
configuration:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<interfaces>
<interface>
<manycast-server>
</manycast-server>
</interface>
</interfaces>
</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>224.0.1.1</address>
</manycast-server>
</interface>
</interfaces>
</ntp>
</data>
9.7. Clock state State
This example describes how to get clock current state - state:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<clock-state>
</clock-state>
</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>
9.8. Get all association All Association
This example describes how to get all association associations present in the
system -
system:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<associations>
</associations>
</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>
<association>
<address>192.0.2.1</address>
<stratum>9</stratum>
<refid>203.0.113.1</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>
</association>
</associations>
</ntp>
</data>
9.9. Global statistic Statistic
This example describes how to get global statistics - statistics:
<get>
<filter type="subtree">
<ntp xmlns="urn:ietf:params:xml:ns:yang:ietf-ntp">
<ntp-statistics>
</ntp-statistics>
</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>
10. IANA Considerations
10.1. IETF XML Registry
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 IESG.
XML: N/A; the requested URI is an XML namespace.
10.2. YANG Module Names
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 XXXX
Note: The RFC Editor will replace XXXX with the number assigned to
this document once it becomes an RFC. 9249
11. 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 Network Configuration Access Control Model (NACM) [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. The 'nacm:default-deny-all' 'nacm:default-deny-
all' is used to prevent retrieval of the key information.
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 -
/ntp/port: This data node specify specifies 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 - /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 -
/ntp/unicast-configuration: The entries in the list include all
unicast configurations (server or peer mode), mode) and indirectly
creates or modify modifies the NTP associations. Unexpected changes
could lead to disruption and/or network misbehavior.
/ntp/interfaces/interface -
/ntp/interfaces/interface: The entries in the list include all
per-interface per-
interface configurations related to broadcast, multicast multicast, and
manycast mode, and indirectly creates or modify modifies the NTP
associations. Unexpected changes could lead to disruption and/or
network misbehavior. It could also lead to syncronization synchronization over
an untrusted source over trusted ones.
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
notification) to these data nodes. These are the subtrees and data
nodes and their sensitivity/vulnerability:
/ntp/authentication/authentication-keys -
/ntp/authentication/authentication-keys: The entries in the list
includes
include all the NTP authentication keys. Unauthorized access to
the keys can be easily exploited to permit unauthorized access to
the NTP service. This information is sensitive and thus sensitive; thus,
unauthorized access to this needs to be curtailed.
/ntp/associations/association/ -
/ntp/associations/association/: The entries in the list includes include all
active NTP associations of all modes. Exposure of these nodes
could reveal network topology or trust relationship. relationships.
Unauthorized access to this also needs to be curtailed.
/ntp/authentication and /ntp/access-rules - /ntp/access-rules: The entries in the list
include the authentication and access control configurations.
Exposure of these nodes could reveal network topology or trust
relationship.
relationships.
Some of the RPC operations in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control access to these operations. These are the
operations and their sensitivity/vulnerability:
statistics-reset -
statistics-reset: The RPC is used to reset statistics. Unauthorized
reset could impact monitoring.
The leaf /ntp/authentication/authentication-keys/algorithm can be set
to cryptographic algorithms that are no longer considered to be
secure. As per [RFC8573], AES-CMAC is the recommended algorithm.
12. Acknowledgments
The authors would like to express their thanks to Sladjana Zoric,
Danny Mayer, Harlan Stenn, Ulrich Windl, Miroslav Lichvar, Maurice
Angermann, Watson Ladd, and Rich Salz for their review and
suggestions.
Thanks to Andy Bierman for the YANG doctor review.
Thanks to Dieter Sibold for being the document shepherd and Erik
Kline for being the responsible AD.
Thanks to Takeshi Takahashi for SECDIR review. Thanks to Tim Evens
for GENART review.
A special thanks to Tom Petch for a very detailed YANG review and
providing great suggestions for improvements.
Thanks for the IESG review from Benjamin Kaduk, Francesca Palombini,
Eric Vyncke, Murray Kucherawy, Robert Wilton, Roman Danyliw, and
Zaheduzzaman Sarker.
13. References
13.1.
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[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>.
[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>.
[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>.
[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>.
[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>.
[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>.
[RFC8519] Jethanandani, M., Agarwal, S., Huang, L., and D. Blair,
"YANG Data Model for Network Access Control Lists (ACLs)",
RFC 8519, DOI 10.17487/RFC8519, March 2019,
<https://www.rfc-editor.org/info/rfc8519>.
[RFC8573] Malhotra, A. and S. Goldberg, "Message Authentication Code
for the Network Time Protocol", RFC 8573,
DOI 10.17487/RFC8573, June 2019,
<https://www.rfc-editor.org/info/rfc8573>.
13.2.
12.2. Informative References
[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>.
[RFC1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
DOI 10.17487/RFC1321, April 1992,
<https://www.rfc-editor.org/info/rfc1321>.
[RFC3174] Eastlake 3rd, D. and P. Jones, "US Secure Hash Algorithm 1
(SHA1)", RFC 3174, DOI 10.17487/RFC3174, September 2001,
<https://www.rfc-editor.org/info/rfc3174>.
[RFC4493] Song, JH., Poovendran, R., Lee, J., and T. Iwata, "The
AES-CMAC Algorithm", RFC 4493, DOI 10.17487/RFC4493, June
2006, <https://www.rfc-editor.org/info/rfc4493>.
[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>.
[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>.
[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>.
[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>.
[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/info/rfc8792>.
[SHS] NIST, "Secure Hash Standard (SHS)", FIPS PUB 180-4, March
2012, <https://nvlpubs.nist.gov/nistpubs/fips/
nist.fips.180-4.pdf>.
Appendix A. Full YANG Tree
The full tree for the ietf-ntp YANG data model is - as follows.
module: ietf-ntp
+--rw ntp!
+--rw port? inet:port-number {ntp-port}?
+--rw refclock-master!
| +--rw master-stratum? ntp-stratum
+--rw authentication {authentication}?
| +--rw auth-enabled? boolean
| +--rw authentication-keys* [key-id]
| +--rw key-id uint32
| +--rw algorithm? identityref
| +--rw key
| | +--rw (key-string-style)?
| | +--:(keystring)
| | | +--rw keystring? string {deprecated}?
| | +--:(hexadecimal) {hex-key-string}?
| | +--rw hexadecimal-string? yang:hex-string
| +--rw istrusted? boolean
+--rw access-rules {access-rules}?
| +--rw access-rule* [access-mode]
| +--rw access-mode identityref
| +--rw acl? -> /acl:acls/acl/name
+--ro clock-state
| +--ro system-status
| +--ro clock-state identityref
| +--ro clock-stratum ntp-stratum
| +--ro clock-refid refid
| +--ro associations-address?
| | -> /ntp/associations/association/address
| +--ro associations-local-mode?
| | -> /ntp/associations/association/local-mode
| +--ro associations-isconfigured?
| | -> /ntp/associations/association/isconfigured
| +--ro nominal-freq decimal64
| +--ro actual-freq decimal64
| +--ro clock-precision log2seconds
| +--ro clock-offset? decimal64
| +--ro root-delay? decimal64
| +--ro root-dispersion? decimal64
| +--ro reference-time? ntp-date-and-time
| +--ro sync-state identityref
+--rw unicast-configuration* [address type]
| {unicast-configuration}?
| +--rw address inet:ip-address
| +--rw type identityref
| +--rw authentication {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? log2seconds
| +--rw maxpoll? log2seconds
| +--rw port? inet:port-number {ntp-port}?
| +--rw version? ntp-version
+--rw associations
| +--ro association* [address local-mode isconfigured]
| +--ro address inet:ip-address
| +--ro local-mode identityref
| +--ro isconfigured boolean
| +--ro stratum? ntp-stratum
| +--ro refid? refid
| +--ro authentication?
| | -> /ntp/authentication/authentication-keys/key-id
| | {authentication}?
| +--ro prefer? boolean
| +--ro peer-interface? if:interface-ref
| +--ro minpoll? log2seconds
| +--ro maxpoll? log2seconds
| +--ro port? inet:port-number {ntp-port}?
| +--ro version? ntp-version
| +--ro reach? uint8
| +--ro unreach? uint8
| +--ro poll? log2seconds
| +--ro now? uint32
| +--ro offset? decimal64
| +--ro delay? decimal64
| +--ro dispersion? decimal64
| +--ro originate-time? ntp-date-and-time
| +--ro receive-time? ntp-date-and-time
| +--ro transmit-time? ntp-date-and-time
| +--ro input-time? ntp-date-and-time
| +--ro ntp-statistics
| +--ro discontinuity-time? ntp-date-and-time
| +--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! {broadcast-server}?
| | +--rw ttl? uint8
| | +--rw authentication {authentication}?
| | | +--rw (authentication-type)?
| | | +--:(symmetric-key)
| | | +--rw key-id? leafref
| | +--rw minpoll? log2seconds
| | +--rw maxpoll? log2seconds
| | +--rw port? inet:port-number {ntp-port}?
| | +--rw version? ntp-version
| +--rw broadcast-client! {broadcast-client}?
| +--rw multicast-server* [address] {multicast-server}?
| | +--rw address
| | | rt-types:ip-multicast-group-address
| | +--rw ttl? uint8
| | +--rw authentication {authentication}?
| | | +--rw (authentication-type)?
| | | +--:(symmetric-key)
| | | +--rw key-id? leafref
| | +--rw minpoll? log2seconds
| | +--rw maxpoll? log2seconds
| | +--rw port? inet:port-number {ntp-port}?
| | +--rw version? ntp-version
| +--rw multicast-client* [address] {multicast-client}?
| | +--rw address rt-types:ip-multicast-group-address
| +--rw manycast-server* [address] {manycast-server}?
| | +--rw address rt-types:ip-multicast-group-address
| +--rw manycast-client* [address] {manycast-client}?
| +--rw address
| | rt-types:ip-multicast-group-address
| +--rw authentication {authentication}?
| | +--rw (authentication-type)?
| | +--:(symmetric-key)
| | +--rw key-id? leafref
| +--rw ttl? uint8
| +--rw minclock? uint8
| +--rw maxclock? uint8
| +--rw beacon? log2seconds
| +--rw minpoll? log2seconds
| +--rw maxpoll? log2seconds
| +--rw port? inet:port-number {ntp-port}?
| +--rw version? ntp-version
+--ro ntp-statistics
+--ro discontinuity-time? ntp-date-and-time
+--ro packet-sent? yang:counter32
+--ro packet-sent-fail? yang:counter32
+--ro packet-received? yang:counter32
+--ro packet-dropped? yang:counter32
rpcs:
+---x statistics-reset
+---w input
+---w (association-or-all)?
+--:(association)
| +---w associations-address?
| | -> /ntp/associations/association/address
| +---w associations-local-mode?
| | -> /ntp/associations/association/local-mode
| +---w associations-isconfigured?
| -> /ntp/associations/association/isconfigured
+--:(all)
Acknowledgments
The authors would like to express their thanks to Sladjana Zoric,
Danny Mayer, Harlan Stenn, Ulrich Windl, Miroslav Lichvar, Maurice
Angermann, Watson Ladd, and Rich Salz for their review and
suggestions.
Thanks to Andy Bierman for the YANG doctor review.
Thanks to Dieter Sibold for being the Document Shepherd and Erik
Kline for being the Responsible AD.
Thanks to Takeshi Takahashi for SECDIR review. Thanks to Tim Evens
for GENART review.
A special thanks to Tom Petch for a very detailed YANG review and
providing great suggestions for improvements.
Thanks for the IESG review from Benjamin Kaduk, Francesca Palombini,
Eric Vyncke, Murray Kucherawy, Robert Wilton, Roman Danyliw, and
Zaheduzzaman Sarker.
Authors' Addresses
Nan Wu
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing
100095
China
Email: eric.wu@huawei.com
Dhruv Dhody (editor)
Huawei
Divyashree Techno Park, Whitefield
Bangalore 560066
Kanataka
India
Email: dhruv.ietf@gmail.com
Ankit kumar Kumar Sinha (editor)
RtBrick Inc.
Bangalore
Kanataka
India
Email: ankit.ietf@gmail.com
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