Internet DRAFT - draft-ietf-tictoc-1588v2-yang
draft-ietf-tictoc-1588v2-yang
Internet Working Group Y. Jiang, Ed.
Huawei
Internet-Draft X. Liu
Independent
Intended status: Standards Track J. Xu
Huawei
R. Cummings, Ed.
National Instruments
Expires: July 2019 January 3, 2019
YANG Data Model for IEEE 1588-2008
draft-ietf-tictoc-1588v2-yang-11
Abstract
This document defines a YANG data model for the configuration of
IEEE 1588-2008 devices and clocks, and also retrieval of the
configuration information, data set and running states of IEEE
1588-2008 clocks. The YANG module in this document conforms to the
Network Management Datastore Architecture (NMDA).
Status of this Memo
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Copyright Notice
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Table of Contents
1. Introduction .............................................. 2
1.1. Conventions used in this document ...................... 4
1.2. Terminology ............................................ 4
2. IEEE 1588-2008 YANG Model hierarchy ....................... 5
2.1. Interpretations from IEEE 1588 Working Group ........... 8
2.2. Configuration and state ................................ 8
3. IEEE 1588-2008 YANG Module ................................ 9
4. Security Considerations .................................. 22
5. IANA Considerations ...................................... 23
6. References ............................................... 23
6.1. Normative References .................................. 23
6.2. Informative References ................................ 24
7. Acknowledgments .......................................... 25
Appendix A Transferring YANG Work to IEEE 1588 WG ............ 26
A.1. Assumptions for the Transfer .......................... 27
A.2. Intellectual Property Considerations .................. 27
A.3. Namespace and Module Name ............................. 28
A.4. IEEE 1588 YANG Modules in ASCII Format ................ 29
1. Introduction
As a synchronization protocol, IEEE 1588-2008 [IEEE1588] is widely
supported in the carrier networks, industrial networks, automotive
networks, and many other applications. It can provide high
precision time synchronization as fine as nano-seconds. The
protocol depends on a Precision Time Protocol (PTP) engine to
decide its own state automatically, and a PTP transportation layer
to carry the PTP timing and various quality messages. The
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configuration parameters and state data sets of IEEE 1588-2008 are
numerous.
According to the concepts described in [RFC3444], IEEE 1588-2008
itself provides an information model in its normative
specifications for the data sets (in IEEE 1588-2008 clause 8). Some
standardization organizations including the IETF have specified
data models in MIBs (Management Information Bases) for IEEE 1588-
2008 data sets (e.g. [RFC8173], [IEEE8021AS]). These MIBs are
typically focused on retrieval of state data using the Simple
Network Management Protocol (SNMP), furthermore, configuration of
PTP data sets is not considered in [RFC8173].
Some service providers and applications require that the management
of the IEEE 1588-2008 synchronization network be flexible and more
Internet-based (typically overlaid on their transport networks).
Software Defined Network (SDN) is another driving factor, which
demands an improved configuration capability of synchronization
networks.
YANG [RFC7950] is a data modeling language used to model
configuration and state data manipulated by network management
protocols like the Network Configuration Protocol (NETCONF)
[RFC6241]. A small set of built-in data types are defined in
[RFC7950], and a collection of common data types are further
defined in [RFC6991]. Advantages of YANG include Internet based
configuration capability, validation, rollback and so on. All of
these characteristics make it attractive to become another
candidate modeling language for IEEE 1588-2008.
This document defines a YANG data model for the configuration of
IEEE 1588-2008 devices and clocks, and retrieval of the state data
of IEEE 1588-2008 clocks. The data model is based on the PTP data
sets as specified in [IEEE1588]. The technology specific IEEE 1588-
2008 information, e.g., those specifically implemented by a bridge,
a router or a telecom profile, is out of scope of this document.
The YANG module in this document conforms to the Network Management
Datastore Architecture (NMDA) [RFC8342].
When used in practice, network products in support of
synchronization typically conform to one or more IEEE 1588-2008
profiles. Each profile specifies how IEEE 1588-2008 is used in a
given industry (e.g. telecom, automotive) and application. A
profile can require features that are optional in IEEE 1588-2008,
and it can specify new features that use IEEE 1588-2008 as a
foundation.
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It is expected that the IEEE 1588-2008 YANG module be used as
follows:
o The IEEE 1588-2008 YANG module can be used as-is for products
that conform to one of the default profiles specified in IEEE 1588-
2008.
o When the IEEE 1588 standard is revised (e.g. the IEEE 1588
revision in progress at the time of writing this document), it will
add some new optional features to its data sets. The YANG module
of this document can be revised and extended to support these new
features. Moreover, the YANG "revision" MUST be used to indicate
changes to the YANG module under such a circumstance.
o A profile standard based on IEEE 1588-2008 may create a
dedicated YANG module for its profile. The profile's YANG module
SHOULD use YANG "import" to import the IEEE 1588-2008 YANG module
as its foundation. Then the profile's YANG module SHOULD use YANG
"augment" to add any profile-specific enhancements.
o A product that conforms to a profile standard may also create
its own YANG module. The product's YANG module SHOULD "import" the
profile's module, and then use YANG "augment" to add any product-
specific enhancements.
1.1. Conventions used in this document
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.
1.2. Terminology
Most terminologies used in this document are extracted from
[IEEE1588].
BC Boundary Clock, see Section 3.1.3 of [IEEE1588]
DS Data Set
E2E End-to-End
EUI Extended Unique Identifier
GPS Global Positioning System
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IANA Internet Assigned Numbers Authority
IP Internet Protocol
NIST National Institute of Standards and Technology
NTP Network Time Protocol
OC Ordinary Clock, see Section 3.1.22 of [IEEE1588]
P2P Peer-to-Peer
PTP Precision Time Protocol
TAI International Atomic Time
TC Transparent Clock, see Section 3.1.46 of [IEEE1588]
UTC Coordinated Universal Time
PTP data set
Structured attributes of clocks (an OC, BC or TC) used for
PTP protocol decisions and for providing values for PTP
message fields, see Section 8 of [IEEE1588].
PTP instance
A PTP implementation in the device (i.e., an OC or BC)
represented by a specific PTP data set.
2. IEEE 1588-2008 YANG Model hierarchy
This section describes the hierarchy of an IEEE 1588-2008 YANG
module. Query and configuration of device wide or port specific
configuration information and clock data set are described for this
version.
Query and configuration of clock information include:
(Note: The attribute names are consistent with IEEE 1588-2008, but
changed to the YANG style, i.e., using all lower-case, with dashes
between words.)
- Clock data set attributes in a clock node, including: current-ds,
parent-ds, default-ds, time-properties-ds, and transparent-clock-
default-ds.
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- Port-specific data set attributes, including: port-ds and
transparent-clock-port-ds.
The readers are assumed to be familiar with IEEE 1588-2008. As all
PTP terminologies and PTP data set attributes are described in
details in IEEE 1588-2008 [IEEE1588], this document only outlines
each of them in the YANG module.
A simplified YANG tree diagram [RFC8340] representing the data
model is typically used by YANG modules. This document uses the
same tree diagram syntax as described in [RFC8340].
module: ietf-ptp
+--rw ptp
+--rw instance-list* [instance-number]
| +--rw instance-number uint32
| +--rw default-ds
| | +--rw two-step-flag? boolean
| | +--ro clock-identity? clock-identity-type
| | +--rw number-ports? uint16
| | +--rw clock-quality
| | | +--rw clock-class? uint8
| | | +--rw clock-accuracy? uint8
| | | +--rw offset-scaled-log-variance? uint16
| | +--rw priority1? uint8
| | +--rw priority2? uint8
| | +--rw domain-number? uint8
| | +--rw slave-only? boolean
| +--rw current-ds
| | +--rw steps-removed? uint16
| | +--rw offset-from-master? time-interval-type
| | +--rw mean-path-delay? time-interval-type
| +--rw parent-ds
| | +--rw parent-port-identity
| | | +--rw clock-identity? clock-identity-type
| | | +--rw port-number? uint16
| | +--rw parent-stats? boolean
| | +--rw observed-parent-offset-scaled-log-variance? uint16
| | +--rw observed-parent-clock-phase-change-rate? int32
| | +--rw grandmaster-identity? clock-identity-type
| | +--rw grandmaster-clock-quality
| | | +--rw clock-class? uint8
| | | +--rw clock-accuracy? uint8
| | | +--rw offset-scaled-log-variance? uint16
| | +--rw grandmaster-priority1? uint8
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| | +--rw grandmaster-priority2? uint8
| +--rw time-properties-ds
| | +--rw current-utc-offset-valid? boolean
| | +--rw current-utc-offset? int16
| | +--rw leap59? boolean
| | +--rw leap61? boolean
| | +--rw time-traceable? boolean
| | +--rw frequency-traceable? boolean
| | +--rw ptp-timescale? boolean
| | +--rw time-source? uint8
| +--rw port-ds-list* [port-number]
| +--rw port-number uint16
| +--rw port-state? port-state-enumeration
| +--rw underlying-interface? if:interface-ref
| +--rw log-min-delay-req-interval? int8
| +--rw peer-mean-path-delay? time-interval-type
| +--rw log-announce-interval? int8
| +--rw announce-receipt-timeout? uint8
| +--rw log-sync-interval? int8
| +--rw delay-mechanism? delay-mechanism-enumeration
| +--rw log-min-pdelay-req-interval? int8
| +--rw version-number? uint8
+--rw transparent-clock-default-ds
| +--ro clock-identity? clock-identity-type
| +--rw number-ports? uint16
| +--rw delay-mechanism? delay-mechanism-enumeration
| +--rw primary-domain? uint8
+--rw transparent-clock-port-ds-list* [port-number]
+--rw port-number uint16
+--rw log-min-pdelay-req-interval? int8
+--rw faulty-flag? boolean
+--rw peer-mean-path-delay? time-interval-type
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2.1. Interpretations from IEEE 1588 Working Group
The preceding model and the associated YANG module have some subtle
differences from the data set specifications of IEEE Std 1588-2008.
These differences are based on interpretation from the IEEE 1588
Working Group, and are intended to provide compatibility with
future revisions of the IEEE 1588 standard.
In IEEE Std 1588-2008, a physical product can implement multiple
PTP clocks (i.e., ordinary, boundary, or transparent clock). As
specified in 1588-2008 subclause 7.1, each of the multiple clocks
operates in an independent domain. However, the organization of
multiple PTP domains was not clear in the data sets of IEEE Std
1588-2008. This document introduces the concept of PTP instance as
described in the new revision of IEEE 1588. The instance concept is
used exclusively to allow for optional support of multiple domains.
The instance number has no usage within PTP messages.
Based on statements in IEEE 1588-2008 subclauses 8.3.1 and 10.1,
most transparent clock products have interpreted the transparent
clock data sets to reside as a singleton at the root level of the
managed product, and this YANG model reflects that location.
2.2. Configuration and state
The information model of IEEE Std 1588-2008 classifies each member
in PTP data sets as one of the following:
- Configurable: Writable by management.
- Dynamic: Read-only to management, and the value is changed by
1588 protocol operation.
- Static: Read-only to management, and the value typically does not
change.
For details on the classification of each PTP data set member,
refer to the IEEE Std 1588-2008 specification for that member.
Under certain circumstances, the classification of an IEEE 1588
data set member may change for a YANG implementation, for example,
a configurable member needs to be changed to read-only. In such a
case, an implementation SHOULD choose to return a warning upon
writing to a read-only member, or use the deviation mechanism to
develop a new deviation model as described in Section 7.20.3 of
[RFC7950].
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3. IEEE 1588-2008 YANG Module
This module imports typedef "interface-ref" from [RFC8343]. Most
attributes are based on the information model defined in [IEEE1588],
but their names are adapted to the YANG style of naming.
<CODE BEGINS> file "ietf-ptp@2018-09-10.yang"
//Note to RFC Editor: update the date to date of publication
module ietf-ptp {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-ptp";
prefix "ptp";
import ietf-interfaces {
prefix if;
reference
"RFC8343: A YANG Data Model for Interface Management";
}
organization "IETF TICTOC Working Group";
contact
"WG Web: http://tools.ietf.org/wg/tictoc/
WG List: <mailto:tictoc@ietf.org>
Editor: Yuanlong Jiang
<mailto:jiangyuanlong@huawei.com>
Editor: Rodney Cummings
<mailto:rodney.cummings@ni.com>";
description
"This YANG module defines a data model for the configuration
of IEEE 1588-2008 clocks, and also for retrieval of the state
data of IEEE 1588-2008 clocks.";
revision "2018-09-10" {
//Note to RFC Editor: update the date to date of publication
description "Initial version";
reference "RFC XXXX: YANG Data Model for IEEE 1588-2008";
//Note to RFC Editor: update RFC XXXX to the actual RFC number
}
typedef delay-mechanism-enumeration {
type enumeration {
enum e2e {
value 1;
description
"The port uses the delay request-response mechanism.";
}
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enum p2p {
value 2;
description
"The port uses the peer delay mechanism.";
}
enum disabled {
value 254;
description
"The port does not implement any delay mechanism.";
}
}
description
"The propagation delay measuring option used by the
port. Values for this enumeration are specified
by the IEEE 1588 standard exclusively.";
reference
"IEEE Std 1588-2008: 8.2.5.4.4";
}
typedef port-state-enumeration {
type enumeration {
enum initializing {
value 1;
description
"The port is initializing its data sets, hardware, and
communication facilities.";
}
enum faulty {
value 2;
description
"The port is in the fault state.";
}
enum disabled {
value 3;
description
"The port is disabled, and is not communicating PTP
messages (other than possibly PTP management
messages).";
}
enum listening {
value 4;
description
"The port is listening for an Announce message.";
}
enum pre-master {
value 5;
description
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"The port is in the pre-master state.";
}
enum master {
value 6;
description
"The port is behaving as a master port.";
}
enum passive {
value 7;
description
"The port is in the passive state.";
}
enum uncalibrated {
value 8;
description
"A master port has been selected, but the port is still
in the uncalibrated state.";
}
enum slave {
value 9;
description
"The port is synchronizing to the selected master port.";
}
}
description
"The current state of the protocol engine associated
with the port. Values for this enumeration are specified
by the IEEE 1588 standard exclusively.";
reference
"IEEE Std 1588-2008: 8.2.5.3.1, 9.2.5";
}
typedef time-interval-type {
type int64;
description
"Derived data type for time interval, represented in units of
nanoseconds and multiplied by 2^16";
reference
"IEEE Std 1588-2008: 5.3.2";
}
typedef clock-identity-type {
type binary {
length "8";
}
description
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"Derived data type to identify a clock";
reference
"IEEE Std 1588-2008: 5.3.4";
}
grouping clock-quality-grouping {
description
"Derived data type for quality of a clock, which contains
clockClass, clockAccuracy and offsetScaledLogVariance.";
reference
"IEEE Std 1588-2008: 5.3.7";
leaf clock-class {
type uint8;
default 248;
description
"The clockClass denotes the traceability of the time
or frequency distributed by the clock.";
}
leaf clock-accuracy {
type uint8;
description
"The clockAccuracy indicates the expected accuracy
of the clock.";
}
leaf offset-scaled-log-variance {
type uint16;
description
"The offsetScaledLogVariance provides an estimate of
the variations of the clock from a linear timescale
when it is not synchronized to another clock
using the protocol.";
}
}
container ptp {
description
"The PTP struct containing all attributes of PTP data set,
other optional PTP attributes can be augmented as well.";
list instance-list {
key "instance-number";
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description
"List of one or more PTP data sets in the device (see IEEE
Std 1588-2008 subclause 6.3).
Each PTP data set represents a distinct instance of
PTP implementation in the device (i.e., distinct
Ordinary Clock or Boundary Clock).";
leaf instance-number {
type uint32;
description
"The instance number of the current PTP instance.
This instance number is used for management purposes
only. This instance number does not represent the PTP
domain number, and is not used in PTP messages.";
}
container default-ds {
description
"The default data set of the clock (see IEEE Std
1588-2008 subclause 8.2.1). This data set represents
the configuration/state required for operation
of Precision Time Protocol (PTP) state machines.";
leaf two-step-flag {
type boolean;
description
"When set to true, the clock is a two-step clock;
otherwise,the clock is a one-step clock.";
}
leaf clock-identity {
type clock-identity-type;
config false;
description
"The clockIdentity of the local clock";
}
leaf number-ports {
type uint16;
description
"The number of PTP ports on the instance.";
}
container clock-quality {
description
"The clockQuality of the local clock.";
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uses clock-quality-grouping;
}
leaf priority1 {
type uint8;
description
"The priority1 attribute of the local clock.";
}
leaf priority2{
type uint8;
description
"The priority2 attribute of the local clock.";
}
leaf domain-number {
type uint8;
description
"The domain number of the current syntonization
domain.";
}
leaf slave-only {
type boolean;
description
"When set to true, the clock is a slave-only clock.";
}
}
container current-ds {
description
"The current data set of the clock (see IEEE Std
1588-2008 subclause 8.2.2). This data set represents
local states learned from the exchange of
Precision Time Protocol (PTP) messages.";
leaf steps-removed {
type uint16;
default 0;
description
"The number of communication paths traversed
between the local clock and the grandmaster clock.";
}
leaf offset-from-master {
type time-interval-type;
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description
"The current value of the time difference between
a master and a slave clock as computed by the slave.";
}
leaf mean-path-delay {
type time-interval-type;
description
"The current value of the mean propagation time between
a master and a slave clock as computed by the slave.";
}
}
container parent-ds {
description
"The parent data set of the clock (see IEEE Std 1588-2008
subclause 8.2.3).";
container parent-port-identity {
description
"The portIdentity of the port on the master, it
contains two members: clockIdentity and portNumber.";
reference
"IEEE Std 1588-2008: 5.3.5";
leaf clock-identity {
type clock-identity-type;
description
"Identity of the clock";
}
leaf port-number {
type uint16;
description
"Port number";
}
}
leaf parent-stats {
type boolean;
default false;
description
"When set to true, the values of
observedParentOffsetScaledLogVariance and
observedParentClockPhaseChangeRate of parentDS
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have been measured and are valid.";
}
leaf observed-parent-offset-scaled-log-variance {
type uint16;
default 65535;
description
"An estimate of the parent clock's PTP variance
as observed by the slave clock.";
}
leaf observed-parent-clock-phase-change-rate {
type int32;
description
"An estimate of the parent clock's phase change rate
as observed by the slave clock.";
}
leaf grandmaster-identity {
type clock-identity-type;
description
"The clockIdentity attribute of the grandmaster clock.";
}
container grandmaster-clock-quality {
description
"The clockQuality of the grandmaster clock.";
uses clock-quality-grouping;
}
leaf grandmaster-priority1 {
type uint8;
description
"The priority1 attribute of the grandmaster clock.";
}
leaf grandmaster-priority2 {
type uint8;
description
"The priority2 attribute of the grandmaster clock.";
}
}
container time-properties-ds {
description
"The timeProperties data set of the clock (see
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IEEE Std 1588-2008 subclause 8.2.4).";
leaf current-utc-offset-valid {
type boolean;
description
"When set to true, the current UTC offset is valid.";
}
leaf current-utc-offset {
when "../current-utc-offset-valid='true'";
type int16;
description
"The offset between TAI and UTC when the epoch of the
PTP system is the PTP epoch in units of seconds, i.e.,
when ptp-timescale is TRUE; otherwise, the value has
no meaning.";
}
leaf leap59 {
type boolean;
description
"When set to true, the last minute of the current UTC
day contains 59 seconds.";
}
leaf leap61 {
type boolean;
description
"When set to true, the last minute of the current UTC
day contains 61 seconds.";
}
leaf time-traceable {
type boolean;
description
"When set to true, the timescale and the
currentUtcOffset are traceable to a primary
reference.";
}
leaf frequency-traceable {
type boolean;
description
"When set to true, the frequency determining the
timescale is traceable to a primary reference.";
}
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leaf ptp-timescale {
type boolean;
description
"When set to true, the clock timescale of the
grandmaster clock is PTP; otherwise, the timescale is
ARB
(arbitrary).";
}
leaf time-source {
type uint8;
description
"The source of time used by the grandmaster clock.";
}
}
list port-ds-list {
key "port-number";
description
"List of port data sets of the clock (see IEEE Std
1588-2008 subclause 8.2.5).";
leaf port-number {
type uint16;
description
"Port number.
The data sets (i.e., information model) of IEEE Std
1588-2008 specify a member portDS.portIdentity, which
uses a typed struct with members clockIdentity and
portNumber.
In this YANG data model, portIdentity is not modeled
in the port-ds-list, however, its members are provided
as follows:
portIdentity.portNumber is provided as this port-
number leaf in port-ds-list; and
portIdentity.clockIdentity is provided as the clock-
identity leaf in default-ds of the instance
(i.e., ../../default-ds/clock-identity).";
}
leaf port-state {
type port-state-enumeration;
default "initializing";
description
"Current state associated with the port.";
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}
leaf underlying-interface {
type if:interface-ref;
description
"Reference to the configured underlying interface that
is used by this PTP Port (see RFC 8343).";
}
leaf log-min-delay-req-interval {
type int8;
description
"The base-two logarithm of the minDelayReqInterval
(the minimum permitted mean time interval between
successive Delay_Req messages).";
}
leaf peer-mean-path-delay {
type time-interval-type;
default 0;
description
"An estimate of the current one-way propagation delay
on the link when the delayMechanism is P2P; otherwise,
it is zero.";
}
leaf log-announce-interval {
type int8;
description
"The base-two logarithm of the mean
announceInterval (mean time interval between
successive Announce messages).";
}
leaf announce-receipt-timeout {
type uint8;
description
"The number of announceInterval that have to pass
without receipt of an Announce message before the
occurrence of the event ANNOUNCE_RECEIPT_TIMEOUT_
EXPIRES.";
}
leaf log-sync-interval {
type int8;
description
"The base-two logarithm of the mean SyncInterval
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for multicast messages. The rates for unicast
transmissions are negotiated separately on a per port
basis and are not constrained by this attribute.";
}
leaf delay-mechanism {
type delay-mechanism-enumeration;
description
"The propagation delay measuring option used by the
port in computing meanPathDelay.";
}
leaf log-min-pdelay-req-interval {
type int8;
description
"The base-two logarithm of the
minPdelayReqInterval (minimum permitted mean time
interval between successive Pdelay_Req messages).";
}
leaf version-number {
type uint8;
description
"The PTP version in use on the port.";
}
}
}
container transparent-clock-default-ds {
description
"The members of the transparentClockDefault data set (see
IEEE Std 1588-2008 subclause 8.3.2).";
leaf clock-identity {
type clock-identity-type;
config false;
description
"The clockIdentity of the transparent clock.";
}
leaf number-ports {
type uint16;
description
"The number of PTP ports on the transparent clock.";
}
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leaf delay-mechanism {
type delay-mechanism-enumeration;
description
"The propagation delay measuring option
used by the transparent clock.";
}
leaf primary-domain {
type uint8;
default 0;
description
"The domainNumber of the primary syntonization domain (see
IEEE Std 1588-2008 subclause 10.1).";
}
}
list transparent-clock-port-ds-list {
key "port-number";
description
"List of transparentClockPort data sets of the transparent
clock (see IEEE Std 1588-2008 subclause 8.3.3).";
leaf port-number {
type uint16;
description
"Port number.
The data sets (i.e., information model) of IEEE Std
1588-2008 specify a member
transparentClockPortDS.portIdentity, which uses a typed
struct with members clockIdentity and portNumber.
In this YANG data model, portIdentity is not modeled in
the transparent-clock-port-ds-list, however, its
members are provided as follows:
portIdentity.portNumber is provided as this leaf member
in transparent-clock-port-ds-list; and
portIdentity.clockIdentity is provided as the clock-
identity leaf in transparent-clock-default-ds
(i.e., ../../transparent-clock-default-ds/clock-
identity).";
}
leaf log-min-pdelay-req-interval {
type int8;
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description
"The logarithm to the base 2 of the
minPdelayReqInterval (minimum permitted mean time
interval between successive Pdelay_Req messages).";
}
leaf faulty-flag {
type boolean;
default false;
description
"When set to true, the port is faulty.";
}
leaf peer-mean-path-delay {
type time-interval-type;
default 0;
description
"An estimate of the current one-way propagation delay
on the link when the delayMechanism is P2P; otherwise,
it is zero.";
}
}
}
}
<CODE ENDS>
4. 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]. Furthermore,
general security considerations of time protocols are discussed in
[RFC7384].
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 are
writable, and the involved subtrees that are sensitive include:
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/ptp/instance-list specifies an instance (i.e., PTP data sets) for
an OC or BC.
/ptp/transparent-clock-default-ds specifies a default data set for
a TC.
/ptp/transparent-clock-port-ds-list specifies a list of port data
sets for a TC.
Write operations (e.g., edit-config) to these data nodes without
proper protection can have a negative effect on network operations.
Specifically, an inappropriate configuration of them may adversely
impact a PTP synchronization network. For example, loss of
synchronization on a clock, accuracy degradation on a set of clocks,
or even break down of a whole synchronization network.
5. IANA Considerations
This document registers the following URI in the "IETF XML
registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-ptp
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace
This document registers the following YANG module in the "YANG
Module Names" registry [RFC6020]:
Name: ietf-ptp
Namespace: urn:ietf:params:xml:ns:yang:ietf-ptp
Prefix: ptp
Reference: RFC XXXX
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997
[RFC3688] Mealling, M., "The IETF XML Registry", RFC 3688,
January 2004
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF) ", RFC 6020,
October 2010
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[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and Bierman,
A., "Network Configuration Protocol (NETCONF)", RFC 6241,
June 2011
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, June 2011
[RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
July 2013
[RFC7950] Bjorklund, M., "The YANG 1.1 Data Modeling Language", RFC
7950, August 2016
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, January 2017
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, May 2017
[RFC8341] Bierman, A. and Bjorklund, M., "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 8341, March
2018
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, March 2018
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, March 2018
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS)
Protocol Version 1.3", RFC 8446, August 2018
[IEEE1588] IEEE, "IEEE Standard for a Precision Clock
Synchronization Protocol for Networked Measurement and
Control Systems", IEEE Std 1588-2008, July 2008
6.2. Informative References
[IEEE8021AS] IEEE, "Timing and Synchronizations for Time-Sensitive
Applications in Bridged Local Area Networks", IEEE
802.1AS-2001, 2011
[RFC3444] Pras, A. and J. Schoenwaelder, "On the Difference between
Information Models and Data Models", RFC 3444, January
2003
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[RFC4663] Harrington, D., "Transferring MIB Work from IETF Bridge
MIB WG to IEEE 802.1 WG", RFC 4663, September 2006
[RFC7384] Mizrahi, T., "Security Requirements of Time Protocols in
Packet Switched Networks", RFC 7384, October 2014
[RFC8340] Bjorklund, M., and Berger, L., "YANG Tree Diagrams", RFC
8340, March 2018
[RFC8173] Shankarkumar, V., Montini, L., Frost, T., and Dowd, G.,
"Precision Time Protocol Version 2 (PTPv2) Management
Information Base", RFC 8173, June 2017
7. Acknowledgments
The authors would like to thank Tom Petch, Radek Krejci, Mahesh
Jethanandani, Tal Mizrahi, Opher Ronen, Liang Geng, Alex Campbell,
Joe Gwinn, John Fletcher, William Zhao and Dave Thaler for their
valuable reviews and suggestions, thank Benoit Claise and Radek
Krejci for their validation of the YANG module, and thank Jingfei
Lv and Zitao Wang for their discussions on IEEE 1588 and YANG
respectively.
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Appendix A Transferring YANG Work to IEEE 1588 WG
This Appendix is informational.
This appendix describes a future plan to transition responsibility
for IEEE 1588 YANG modules from the IETF TICTOC Working Group (WG)
to the IEEE 1588 WG, which develops the time synchronization
technology that the YANG modules are designed to manage.
This appendix is forward-looking with regard to future
standardization roadmaps in IETF and IEEE. Since those roadmaps
cannot be predicted with significant accuracy, this appendix is
informational, and it does not specify imperatives or normative
specifications of any kind.
The IEEE 1588-2008 YANG module of this standard represents a
cooperation between IETF (for YANG) and IEEE (for 1588). For the
initial standardization of IEEE-1588 YANG modules, the information
model is relatively clear (i.e., IEEE 1588 data sets), but
expertise in YANG is required, making IETF an appropriate location
for the standards. The TICTOC WG has expertise with IEEE 1588,
making it the appropriate location within IETF.
The IEEE 1588 WG anticipates future changes to its standard on an
ongoing basis. As IEEE 1588 WG members gain practical expertise
with YANG, the IEEE 1588 WG will become more appropriate for
standardization of its YANG modules. As the IEEE 1588 standard is
revised and/or amended, IEEE 1588 members can more effectively
synchronize the revision of this YANG module with future versions
of the IEEE 1588 standard.
This appendix is meant to establish some clear expectations between
IETF and IEEE about the future transfer of IEEE 1588 YANG modules
to the IEEE 1588 WG. The goal is to assist in making the future
transfer as smooth as possible. As the transfer takes place, some
case-by-case situations are likely to arise, which can be handled
by discussion on the IETF TICTOC WG mailing lists and/or
appropriate liaisons.
This appendix obtained insight from [RFC4663], an informational
memo that described a similar transfer of MIB work from the IETF
Bridge MIB WG to the IEEE 802.1 WG.
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A.1. Assumptions for the Transfer
For the purposes of discussion in this appendix, assume that the
IESG has approved the publication of an RFC containing a YANG
module for a published IEEE 1588 standard. As of this writing,
this is IEEE Std 1588-2008, but it is possible that YANG modules
for subsequent 1588 revisions could be published from the IETF
TICTOC WG. For discussion in this appendix, we use the phrase
"last IETF 1588 YANG" to refer to the most recently published 1588
YANG module from the IETF TICTOC WG.
The IEEE-SA Standards Board New Standards Committee (NesCom)
handles new Project Authorization Requests (PARs) (see
http://standards.ieee.org/board/nes/). PARs are roughly the
equivalent of IETF Working Group Charters and include information
concerning the scope, purpose, and justification for
standardization projects.
Assume that IEEE 1588 has an approved PAR that explicitly specifies
development of a YANG module. The transfer of YANG work will occur
in the context of this IEEE 1588 PAR. For discussion in this
appendix, we use the phrase "first IEEE 1588 YANG" to refer to the
first IEEE 1588 standard for YANG.
Assume that as part of the transfer of YANG work, the IETF TICTOC
WG agrees to cease all work on standard YANG modules for IEEE 1588.
Assume that the IEEE 1588 WG has participated in the development of
the last IETF 1588 YANG module, such that the first IEEE 1588 YANG
module will effectively be a revision of it. In other words, the
transfer of YANG work will be relatively clean.
The actual conditions for the future transfer can be such that the
preceding assumptions do not hold. Exceptions to the assumptions
will need to be addressed on a case-by-case basis at the time of
the transfer. This appendix describes topics that can be addressed
based on the preceding assumptions.
A.2. Intellectual Property Considerations
During review of the legal issues associated with transferring
Bridge MIB WG documents to the IEEE 802.1 WG (Section 3.1 and
Section 9 of [RFC4663]), it was concluded that the IETF does not
have sufficient legal authority to make the transfer to IEEE
without the consent of the document authors.
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If the last IETF 1588 YANG is published as a RFC, the work is
required to be transferred from the IETF to the IEEE, so that IEEE
1588 WG can begin working on the first IEEE 1588 YANG.
When work on the first IEEE YANG module begins in the IEEE 1588 WG,
that work derives from the last IETF YANG module of this RFC,
requiring a transfer of that work from the IETF to the IEEE. In
order to avoid having the transfer of that work be dependent on the
availability of this RFC's authors at the time of its publication,
the IEEE Standards Association department of Risk Management and
Licensing provided the appropriate forms and mechanisms for this
document's authors to assign a non-exclusive license for IEEE to
create derivative works from this document. Those IEEE forms and
mechanisms will be updated as needed for any future IETF YANG
modules for IEEE 1588 (The signed forms are held by the IEEE
Standards Association department of Risk Management and Licensing.).
This will help to make the future transfer of work from IETF to
IEEE occur as smoothly as possible.
As stated in the initial "Status of this Memo", the YANG module in
this document conforms to the provisions of BCP 78. The IETF will
retain all the rights granted at the time of publication in the
published RFCs.
A.3. Namespace and Module Name
As specified in Section 5 "IANA Considerations", the YANG module in
this document uses IETF as the root of its URN namespace and YANG
module name.
Use of IETF as the root of these names implies that the YANG module
is standardized in a Working Group of IETF, using the IETF
processes. If the IEEE 1588 Working Group were to continue using
these names rooted in IETF, the IEEE 1588 YANG standardization
would need to continue in the IETF. The goal of transferring the
YANG work is to avoid this sort of dependency between standards
organizations.
IEEE 802 has an active PAR (IEEE P802d) for creating a URN
namespace for IEEE use (see
http://standards.ieee.org/develop/project/802d.html). It is likely
that this IEEE 802 PAR will be approved and published prior to the
transfer of YANG work to the IEEE 1588 WG. If so, the IEEE 1588 WG
can use the IEEE URN namespace for the first IEEE 1588 YANG module,
such as:
urn:ieee:Std:1588:yang:ieee1588-ptp
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where "ieee1588-ptp" is the registered YANG module name in the IEEE.
Under the assumptions of section A.1, the first IEEE 1588 YANG
module's prefix will be the same as the last IETF 1588 YANG
module's prefix (i.e. "ptp"). Consequently, other YANG modules can
preserve the same import prefix "ptp" to access PTP nodes during
the migration from the last IETF 1588 YANG module to the first IEEE
1588 YANG module.
The result of these name changes are that for complete
compatibility, a server (i.e., IEEE 1588 node) can choose to
implement a YANG module for the last IETF 1588 YANG module (with
IETF root) as well as the first IEEE 1588 YANG module (with IEEE
root). Since the content of the YANG module transferred are the
same, the server implementation is effectively common for both.
From a client's perspective, a client of the last IETF 1588 YANG
module (or earlier) looks for the IETF-rooted module name; and a
client of the first IEEE 1588 YANG module (or later) looks for the
IEEE-rooted module name.
A.4. IEEE 1588 YANG Modules in ASCII Format
Although IEEE 1588 can certainly decide to publish YANG modules
only in the PDF format that they use for their standard documents,
without publishing an ASCII version, most network management
systems cannot import the YANG module directly from the PDF. Thus,
not publishing an ASCII version of the YANG module would negatively
impact implementers and deployers of YANG modules and would make
potential IETF reviews of YANG modules more difficult.
This appendix recommends that the IEEE 1588 WG consider future
plans for:
o Public availability of the ASCII YANG modules during project
development. These ASCII files allow IETF participants to access
these documents for pre-standard review purposes.
o Public availability of the YANG portion of published IEEE 1588
standards, provided as an ASCII file for each YANG module.
These ASCII files are intended for use of the published IEEE
1588 standard.
As an example of public availability during project development,
IEEE 802 uses the same repository that IETF uses for YANG module
development (see https://github.com/YangModels/yang). IEEE branches
are provided for experimental work (i.e. pre-PAR) as well as
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standard work (post-PAR drafts). IEEE-SA has approved use of this
repository for project development, but not for published standards.
As an example of public availability of YANG modules for published
standards, IEEE 802.1 provides a public list of ASCII files for MIB
(see http://www.ieee802.org/1/files/public/MIBs/ and
http://www.ieee802.org/1/pages/MIBS.html), and analogous lists are
planned for IEEE 802.1 YANG files.
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Authors' Addresses
Yuanlong Jiang (Editor)
Huawei Technologies Co., Ltd.
Bantian, Longgang district
Shenzhen 518129, China
Email: jiangyuanlong@huawei.com
Xian Liu
Independent
Shenzhen 518129, China
lene.liuxian@foxmail.com
Jinchun Xu
Huawei Technologies Co., Ltd.
Bantian, Longgang district
Shenzhen 518129, China
xujinchun@huawei.com
Rodney Cummings (Editor)
National Instruments
11500 N. Mopac Expwy
Bldg. C
Austin, TX 78759-3504
Email: Rodney.Cummings@ni.com
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