IEEE 1588 YANG Update

Rodney CummingsIEEE 1588 Working Group Vice Chair

Affiliation: National Instruments

Introduction

• IEEE standard 1588 is a commonly used protocol for time synchronization over Ethernet networks

– ITU-T has standard profiles for IEEE 1588 equipment

• Management of IEEE 1588 equipment is important

– Roadmap for IEEE 1588 YANG is needed

IEEE 1588-2008

IETF RFC 8575

• RFC 8575: YANG Data Model for the Precision Time Protocol (PTP)

– https://www.rfc-editor.org/rfc/rfc8575.html

– Standard YANG model for IEEE 1588-2008 (version 2.0)

– Uses 1588-2008 data set members for YANG nodes

– Published May 2019

Potential Applicability to ITU-T G.8275.1

• Rec. ITU-T G.8275.1/Y.1369.1 (06/2016, and amendments)

– Precision time protocol telecom profile for phase/time synchronization with full timing support from the network

– Profile of IEEE 1588-2008

• Data set member specifications in Annex A

– 52 members specified

– 48 are directly from 1588-2008, included in RFC 8575

– 4 are unique to G.8275.1 (~8%)

YANG Augment

• YANG standard (RFC 7950) anticipates this scenario:

• YANG augment

– Import a base model

– Augment model only specifies the few unique nodes

Example Augment for ITU-T G.8275.1import ietf-ptp { prefix "ptp"; }

augment "/ptp:ptp/ptp:instance-list/ptp:default-ds" {

description

"ITU-T G.8275.1 new members for 1588-2008 default data set.";

leaf local-priority {

type uint8;

}

leaf max-steps-removed {

type uint8;

}

}

augment "/ptp:ptp/ptp:instance-list/ptp:port-ds-list" {

description

"ITU-T G.8275.1 new members for 1588-2008 port data set.";

leaf master-only {

type boolean;

}

leaf local-priority {

type uint8;

}

}

IEEE 1588-2019

IEEE 1588-2019: Recent Revision

• Approved for publication November 2019

– Final editing work is in progress, so not yet available for purchase

• Version 2.1: Compatible with 1588-2008

• Organizational improvements and clarifications

• Many new features

• 1588 Working Group is creating a public summary (in progress)

Improved 1588 Management: Problem

• 1588-2008 specified "data sets"

– Used by protocol, but also used for remote management

• 1588-2008 specified optional features (clauses 16 and 17)

– E.g. Unicast message negotiation, Alternate timescales,Alternate master, Unicast discovery

– 1588-2008 did not always specify data sets for optional features

• Unclear how to manage

Improved 1588 Management: Solution

• 1588-2019 improves 2008 optional features, and add new ones

• 1588-2019 specifies data sets for all these features

– If a feature can be managed, then a data set is specified

• Data sets are now a clear information model for management

– Reference for any modeling language (MIB, YANG, UML, ...)

Example Data Set Member in 1588-2019

1588-2019 Future Work

• MIB and YANG data models were not in scope of 1588-2019

– Nevertheless, 2019 improvements make it straightforward

• 1588 Working Group consensus: Amendment for MIB & YANG

– Project kickoff (PAR) is in progress

– Will include all data sets, including all optional features

– YANG work of RFC 8575 will transfer to 1588 Working Group

• Goal: Keep YANG as compatible as possible from 2008 to 2019

1588 YANG Summary

• YANG for 1588-2008 is published

• 1588-2019 has an improved architecture for management

– Including future amendments and revisions to 1588

• YANG for 1588-2019 is in progress

Thank You