P802.1ASdm – Hot Standby

This amendment specifies protocols, procedures, and managed objects for hot standby without use of the Best Master Clock Algorithm (BMCA), for time-aware systems, including:

  • A function that transforms the synchronized times of two generalized Precision Time Protocol (gPTP) domains into one synchronized time for use by applications;
  • A function that directs the synchronized time of one gPTP domain into a different gPTP domain; and
  • Mechanisms that determine whether a gPTP domain has sufficient quality to be used for hot standby.

This amendment also addresses errors and omissions in the description of existing functionality.

Current Status

DraftP802.1ASdm, Draft 2.5 (8 July 2024)
StatusStandards Association ballot

Full title: Draft Standard for Local and Metropolitan Area Networks: Timing and Synchronization for Time-Sensitive Applications — Amendment: Hot Standby and Clock Drift Error Reduction
PAR (Approved: 05 Jun 2023; Expires: 31 Dec 2024)

EditorGeoffrey Garner
Web pageCraig Gunther


08 Jan 2024P802.1ASdm, Draft 1.5
08 Jan 2024P802.1ASdm, Draft 1.4 WG recirculation comment disposition
07 Dec 2023P802.1ASdm, Draft 1.4
14 Nov 2023P802.1ASdm, Draft 1.3 WG recirculation comment disposition
12 Oct 2023P802.1ASdm, Draft 1.3
09 Oct 2023P802.1ASdm, Draft 1.2 WG recirculation comment disposition
18 Aug 2023P802.1ASdm, Draft 1.2
28 Jul 2023
29 May 2023
22 May 2023
27 Jan 2023
27 Jan 2023
18 Nov 2022
03 Aug 2022
03 Aug 2022
11 Jul 2022
21 Jan 2022
11 Jan 2022
13 Dec 2021
01 Sep 2021
09 Aug 2021
15 Mar 2021

The above list includes only the latest version of (proposed) dispositions. See the project folder for a complete list). The dates listed are the website file dates; they may differ from the creation dates in the documents.


Important NOTICE on contributions.

As assembled by the editor. Notify the editor of any errors or omissions. This list may omit documents superseded by later versions. For the full list of contributions, see filenames beginning “dm-” in the 2020, 2021 and 2022 802.1 public directories. The dates listed are the website file dates and often differ from creation dates in the documents.
DateDocument IDTitleAuthor
2021-11-15dm-turner-ASredundancy-1121-v01.pdfIEEE802.1ASdm – RedundancyMax Turner
2021-09-15dm-turner-text-contribution-0921-v01.pdfContribution towards P802.1ASdm/D0.3 Comment resolutionMax Turner
2021-08-09asdm-garner-discussion-of-maint-items-331-332-0821-v02.pdfDiscussion of Maintenance Items 331 and 332 – Revision 2Geoffrey Garner
2021-06-21dm-Lv-Rodrigues-comment-84-against-d0-2-0621-v00.pdfComment #84 of IEEE Draft P802.1ASdm/D0.2Jingfei Lv, Silvana Rodrigues
2020-11-02dm-garner-plans-1120-v00.pdfInitial Plans and Assumptions for 802.1ASdmGeoffrey Garner
2020-03-09dm-cummings-as-4-domains-0320-v04.pdf802.1AS Hot Standby Amendment: 4 DomainsRodney Cummings
2020-02-18dm-potts-as-hot-standby-multiple-domains-0220-v01.pdfIEEE 802.1AS-2020 Addendum for “Hot-Standby” with multiple domain definitionMichael Potts
2020-01-16new-cummings-as-hot-standby-scope-0120-v02.pdf802.1AS Hot Standby Amendment: Scope DiscussionRodney Cummings

The above list includes only the latest version of updated documents and omits those superseded by subsequent discussion or inclusion in the current draft (see filenames beginning “dm-” in the 2020 or 2021 public directories for a complete list). The dates listed are the website file dates; they may differ from the creation dates in the documents.

Please contact Craig Gunther if you have comments on this page.