NTP Working Group N. Wu Internet-Draft D. Dhody Intended status: Standards Track Huawei Expires: April 18, 2019 A. Sinha A. Kumar S N RtBrick Inc. Y. Zhao Ericsson October 15, 2018 A YANG Data Model for NTP draft-ietf-ntp-yang-data-model-04 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 April 18, 2019. Wu, et al. Expires April 18, 2019 [Page 1] Internet-Draft YANG for NTP October 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 . . . . . . . . . . . . . . . . . 7 4. Relationship with RFC 7317 . . . . . . . . . . . . . . . . . 9 5. Access Rules . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Key Management . . . . . . . . . . . . . . . . . . . . . . . 9 7. NTP YANG Module . . . . . . . . . . . . . . . . . . . . . . . 10 8. Usage Example . . . . . . . . . . . . . . . . . . . . . . . . 31 8.1. Unicast association . . . . . . . . . . . . . . . . . . . 31 8.2. Refclock master . . . . . . . . . . . . . . . . . . . . . 33 8.3. Authentication configuration . . . . . . . . . . . . . . 34 8.4. Access configuration . . . . . . . . . . . . . . . . . . 36 8.5. Multicast configuration . . . . . . . . . . . . . . . . . 36 8.6. Manycast configuration . . . . . . . . . . . . . . . . . 40 8.7. Clock state . . . . . . . . . . . . . . . . . . . . . . . 43 8.8. Get all association . . . . . . . . . . . . . . . . . . . 43 8.9. Global statistic . . . . . . . . . . . . . . . . . . . . 45 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45 10. Security Considerations . . . . . . . . . . . . . . . . . . . 46 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 47 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 47 12.1. Normative References . . . . . . . . . . . . . . . . . . 47 12.2. Informative References . . . . . . . . . . . . . . . . . 49 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 49 Wu, et al. Expires April 18, 2019 [Page 2] Internet-Draft YANG for NTP October 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 April 18, 2019 [Page 3] Internet-Draft YANG for NTP October 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 | +--ro actual-freq decimal64 Wu, et al. Expires April 18, 2019 [Page 4] Internet-Draft YANG for NTP October 2018 | +--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 | +--ro packet-sent? yang:counter32 Wu, et al. Expires April 18, 2019 [Page 5] Internet-Draft YANG for NTP October 2018 | +--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}? | +--rw version? ntp-version +--ro ntp-statistics +--ro packet-sent? yang:counter32 Wu, et al. Expires April 18, 2019 [Page 6] Internet-Draft YANG for NTP October 2018 +--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. 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. Wu, et al. Expires April 18, 2019 [Page 7] Internet-Draft YANG for NTP October 2018 +--------------------------+--------------------------+ | YANG data nodes in /ntp/ | NTPv4-MIB objects | +--------------------------+--------------------------+ | ntp-enabled | ntpEntStatusCurrentMode | +--------------------------+--------------------------+ +--------------------------------------+---------------------+ | YANG data nodes in /ntp/associations | NTPv4-MIB objects | +--------------------------------------+---------------------+ | address | ntpAssocAddressType | | | ntpAssocAddress | +--------------------------------------+---------------------+ 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 Wu, et al. Expires April 18, 2019 [Page 8] Internet-Draft YANG for NTP October 2018 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. +-------------------------------+--------------------------------+ | YANG data nodes in /ntp/ | YANG data nodes in /system/ntp | +-------------------------------+--------------------------------+ | ntp-enabled | 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. Wu, et al. Expires April 18, 2019 [Page 9] Internet-Draft YANG for NTP October 2018 7. NTP YANG Module file "ietf-ntp@2018-10-15.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"; } 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"; } import ietf-routing-types { prefix "rt-types"; reference "RFC 8294"; } organization "IETF NTP (Network Time Protocol) Working Group"; Wu, et al. Expires April 18, 2019 [Page 10] Internet-Draft YANG for NTP October 2018 contact "WG Web: WG List: Editor: Anil Kumar S N Editor: Yi Zhao Editor: Dhruv Dhody Editor: Ankit Kumar Sinha "; description "This YANG module defines essential components for the management of a routing subsystem. 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 XXXX; see the RFC itself for full legal notices."; revision 2018-10-15 { description "Updated revision."; reference "RFC XXXX: A YANG Data Model for NTP Management"; } /* 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 April 18, 2019 [Page 11] Internet-Draft YANG for NTP October 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."; Wu, et al. Expires April 18, 2019 [Page 12] Internet-Draft YANG for NTP October 2018 } enum synchronization { 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."; Wu, et al. Expires April 18, 2019 [Page 13] Internet-Draft YANG for NTP October 2018 } enum active { 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."; } Wu, et al. Expires April 18, 2019 [Page 14] Internet-Draft YANG for NTP October 2018 } description "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 */ Wu, et al. Expires April 18, 2019 [Page 15] Internet-Draft YANG for NTP October 2018 feature ntp-port { description "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"; } Wu, et al. Expires April 18, 2019 [Page 16] Internet-Draft YANG for NTP October 2018 feature manycast-server { 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 Wu, et al. Expires April 18, 2019 [Page 17] Internet-Draft YANG for NTP October 2018 "Type of 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."; leaf packet-sent { type yang:counter32; description "The total number of packets sent."; } leaf packet-sent-fail { type yang:counter32; description "The number of times packet sending failed."; } leaf packet-received { type yang:counter32; description "The total number of packets received."; } leaf packet-dropped { type yang:counter32; description "The number of packets dropped."; } } grouping common-attributes { description "NTP common attributes for configuration."; leaf minpoll { type ntp-minpoll; description "The minimum poll interval used in this association."; Wu, et al. Expires April 18, 2019 [Page 18] Internet-Draft YANG for NTP October 2018 } 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."; } 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 Wu, et al. Expires April 18, 2019 [Page 19] Internet-Draft YANG for NTP October 2018 which result in clock synchronization."; } } /* Configuration data nodes */ container ntp { presence "NTP is enabled"; 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 NTP packets."; } container refclock-master { presence "NTP master clock is enabled"; description "Configures the 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 { 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."; } Wu, et al. Expires April 18, 2019 [Page 20] Internet-Draft YANG for NTP October 2018 } 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."; } leaf acl { type leafref { path "/acl:acls/acl:acl/acl:name"; } description "NTP ACL."; } reference "RFC 1305"; } } container clock-state { config "false"; description "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."; } leaf clock-stratum { type ntp-stratum; mandatory true; description "The stratum of the reference clock."; Wu, et al. Expires April 18, 2019 [Page 21] Internet-Draft YANG for NTP October 2018 } 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"; } 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 Wu, et al. Expires April 18, 2019 [Page 22] Internet-Draft YANG for NTP October 2018 (prec=2^(-n))"; } leaf clock-offset { type decimal64 { fraction-digits 4; } units milliseconds; description "Clock offset with the synchronized peer"; } leaf root-delay { type decimal64 { fraction-digits 2; } units milliseconds; description "Total delay along the path to root clock"; } leaf root-dispersion { type decimal64 { fraction-digits 2; } units milliseconds; description "The dispersion between the local clock and the master reference clock."; } 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 unicast-configuration."; leaf address { type inet:host; description Wu, et al. Expires April 18, 2019 [Page 23] Internet-Draft YANG for NTP October 2018 "Address of this association."; } leaf type { type unicast-configuration-type; description "Type of unicast configuration"; } container authentication{ description "Authentication."; uses authentication; } leaf prefer { type boolean; default "false"; description "Whether this association is 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."; } 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"; Wu, et al. Expires April 18, 2019 [Page 24] Internet-Draft YANG for NTP October 2018 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."; leaf address { type inet:host; description "The address of this association."; } leaf local-mode { type association-mode; description "Local mode for this NTP association."; } leaf isconfigured { type boolean; description "Indicates if this association is configured or dynamically learned."; } leaf stratum { type ntp-stratum; description "Indicates the stratum of the reference clock."; } leaf refid { type union { type inet:ipv4-address; type binary { length "4"; } type string { length "4"; } Wu, et al. Expires April 18, 2019 [Page 25] Internet-Draft YANG for NTP October 2018 } description "Reference clock type or address for the peer."; } leaf authentication{ type leafref { path "/ntp:ntp/ntp:authentication/" + "ntp:authentication-keys/ntp:key-id"; } description "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; Wu, et al. Expires April 18, 2019 [Page 26] Internet-Draft YANG for NTP October 2018 units seconds; description "The time since the NTP packet was not received or last synchronized."; } leaf offset { type decimal64 { fraction-digits 4; } description "The offset between the local clock and the superior reference clock."; } leaf delay { type decimal64 { fraction-digits 2; } description "The delay between the local clock and the superior reference clock."; } leaf dispersion { type decimal64 { fraction-digits 2; } description "The dispersion between the local clock and the superior reference clock."; } leaf originate-time { type yang:date-and-time; description "The packet originate timestamp(T1)."; } leaf receive-time { type yang:date-and-time; description "The packet receive timestamp(T2)."; } leaf transmit-time { type yang:date-and-time; description "The packet transmit timestamp(T3)."; } leaf input-time { type yang:date-and-time; description "The packet input timestamp(T4)."; Wu, et al. Expires April 18, 2019 [Page 27] Internet-Draft YANG for NTP October 2018 } 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) of a broadcast packet."; } container authentication{ description "Authentication."; uses authentication; } uses common-attributes { description "Common attribute like port, version, min and max poll."; } } container broadcast-client { Wu, et al. Expires April 18, 2019 [Page 28] Internet-Draft YANG for NTP October 2018 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) of a multicast packet."; } container authentication{ description "Authentication."; 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 join."; } } list manycast-server { key "address"; description "Configuration of manycast server."; leaf address { Wu, et al. Expires April 18, 2019 [Page 29] Internet-Draft YANG for NTP October 2018 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."; 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."; } leaf beacon { type uint8; description "The maximum interval between beacons in this association."; } uses common-attributes { Wu, et al. Expires April 18, 2019 [Page 30] Internet-Draft YANG for NTP October 2018 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."; } } } } 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 April 18, 2019 [Page 31] Internet-Draft YANG for NTP October 2018
192.0.2.1
server true 4 1025 10 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
192.0.2.1
server 10 true false Wu, et al. Expires April 18, 2019 [Page 32] Internet-Draft YANG for NTP October 2018 true 6 10 1025 4 9 20.1.1.1 255 0 128 10 0.025 0.5 0.6 10-10-2017 07:33:55.253 Z+05:30\ 10-10-2017 07:33:55.258 Z+05:30\ 10-10-2017 07:33:55.300 Z+05:30\ 10-10-2017 07:33:55.305 Z+05:30\ 20 0 20 0 8.2. Refclock master Below is the example on how to configure reference clock with stratum 8 Wu, et al. Expires April 18, 2019 [Page 33] Internet-Draft YANG for NTP October 2018 8 Below is the example on how to get reference clock configuration 8 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 April 18, 2019 [Page 34] Internet-Draft YANG for NTP October 2018 true 10 md5 abcd true Below is the example on how to get authentication related configuration false 10 md5 abcd true Wu, et al. Expires April 18, 2019 [Page 35] Internet-Draft YANG for NTP October 2018 8.4. Access configuration Below is the example on how to configure access mode "peer" associated with acl 2000. peer 2000 Below is the example on how to get access related configuration peer 2000 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 April 18, 2019 [Page 36] Internet-Draft YANG for NTP October 2018 Ethernet3/0/0
224.1.1.1
10 1025 Below is the example on how to get multicast-server related configuration Wu, et al. Expires April 18, 2019 [Page 37] Internet-Draft YANG for NTP October 2018 Ethernet3/0/0
224.1.1.1
224.1.1.1 10 6 10 1025 3 Below is the example on how to configure multicast-client with address as "224.1.1.1" Wu, et al. Expires April 18, 2019 [Page 38] Internet-Draft YANG for NTP October 2018 Ethernet3/0/0
224.1.1.1
 Below is the example on how to get multicast-client related configuration Ethernet3/0/0
224.1.1.1
 Wu, et al. Expires April 18, 2019 [Page 39] Internet-Draft YANG for NTP October 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 Ethernet3/0/0
224.1.1.1
10 1025 Below is the example on how to get manycast-client related configuration Wu, et al. Expires April 18, 2019 [Page 40] Internet-Draft YANG for NTP October 2018 Ethernet3/0/0
224.1.1.1
10 255 3 10 6 6 10 1025 Below is the example on how to configure manycast-server with address as "224.1.1.1" Wu, et al. Expires April 18, 2019 [Page 41] Internet-Draft YANG for NTP October 2018 Ethernet3/0/0
224.1.1.1
 Below is the example on how to get manycast-server related configuration Ethernet3/0/0
224.1.1.1
 Wu, et al. Expires April 18, 2019 [Page 42] Internet-Draft YANG for NTP October 2018 8.7. Clock state Below is the example on how to get clock current state synchronized 7 192.0.2.1 192.0.2.1\ client\ yes\ 100.0 100.0 18 0.025 0.5 0.8 10-10-2017 07:33:55.258 Z+05:30\ clock-synchronized 8.8. Get all association Below is the example on how to get all association present Wu, et al. Expires April 18, 2019 [Page 43] Internet-Draft YANG for NTP October 2018
192.0.2.1
9 20.1.1.1 client true 10 true Ethernet3/0/0 6 10 1025 4 255 0 128 10 0.025 0.5 0.6 10-10-2017 07:33:55.253 Z+05:30\ 10-10-2017 07:33:55.258 Z+05:30\ 10-10-2017 07:33:55.300 Z+05:30\ 10-10-2017 07:33:55.305 Z+05:30\ 20 0 20 0 Wu, et al. Expires April 18, 2019 [Page 44] Internet-Draft YANG for NTP October 2018 8.9. Global statistic Below is the example on how to get clock current state 30 5 20 2 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 NETMOD 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 XXXX Wu, et al. Expires April 18, 2019 [Page 45] Internet-Draft YANG for NTP October 2018 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 notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability: Wu, et al. Expires April 18, 2019 [Page 46] Internet-Draft YANG for NTP October 2018 /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-20 (work in progress), October 2018. [RFC1305] Mills, D., "Network Time Protocol (Version 3) Specification, Implementation and Analysis", RFC 1305, DOI 10.17487/RFC1305, March 1992, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [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, . [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, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . Wu, et al. Expires April 18, 2019 [Page 47] Internet-Draft YANG for NTP October 2018 [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, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [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, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . [RFC8343] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, March 2018, . Wu, et al. Expires April 18, 2019 [Page 48] Internet-Draft YANG for NTP October 2018 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . 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, . [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, . 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 April 18, 2019 [Page 49] Internet-Draft YANG for NTP October 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 April 18, 2019 [Page 50]