Skip to content

Commit 378b036

Browse files
authored
AB#5604 Update support-boundary-high-accuracy-time.md
1 parent fefb9ff commit 378b036

File tree

1 file changed

+20
-20
lines changed

1 file changed

+20
-20
lines changed
Lines changed: 20 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -1,85 +1,85 @@
11
---
2-
title: Support boundary for high-accuracy time
2+
title: Support boundary for high accuracy time
33
description: Describes the support boundary for the Windows Time (W32Time) service in environments that require highly accurate and stable system time.
4-
ms.date: 03/20/2025
4+
ms.date: 04/29/2025
55
manager: dcscontentpm
66
audience: itpro
77
ms.topic: troubleshooting
8-
ms.reviewer: kaushika, dahavey, v-lianna
8+
ms.reviewer: kaushika, dahavey, v-lianna, brackerm
99
ms.custom:
1010
- sap:active directory\windows time service configuration,accuracy,and synchronization
1111
- pcy:WinComm Directory Services
1212
---
13-
# Support boundary for high-accuracy time
13+
# Support boundary for high accuracy time
1414

1515
This article describes the support boundaries for the Windows Time service (W32Time) in environments that require highly accurate and stable system time.
1616

1717
_Applies to:_   Windows Server (All supported versions) including Azure Stack HCI, Windows client (All supported versions)
1818

1919
## High accuracy support for Windows 8.1 and 2012 R2 (or prior)
2020

21-
Earlier versions of Windows (Prior to Windows 10 1607 or Windows Server 2016 1607) can't guarantee highly accurate time. The Windows Time service on these systems:
21+
Earlier versions of Windows (prior to Windows 10 1607 or Windows Server 2016 1607) can't guarantee highly accurate time. The Windows Time service on these systems:
2222

2323
- Provided the necessary time accuracy to satisfy Kerberos version 5 authentication requirements
2424
- Provided loosely accurate time for Windows clients and servers joined to a common Active Directory forest
2525

26-
Tighter accuracy requirements were outside of the design specification of the Windows Time Service on these operating systems and isn't supported.
26+
Tighter accuracy requirements were outside of the design specification of the Windows Time Service on these operating systems and weren't supported.
2727

2828
## Windows 10 and Windows Server 2016
2929

30-
Time accuracy in Windows 10 and Windows Server 2016 has been substantially improved, while maintaining full backwards NTP compatibility with older Windows versions. Under the right operating conditions, systems running Windows 10 or Windows Server 2016 and newer releases can deliver 1 second, 50 ms (milliseconds), or 1-ms accuracy.
30+
Time accuracy in Windows 10 and Windows Server 2016 has been substantially improved, while maintaining full backwards NTP compatibility with older Windows versions. Under the right operating conditions, systems running Windows 10, Windows Server 2016, and newer releases can deliver 1 second, 50 ms (milliseconds), or 1 ms accuracy.
3131

3232
> [!IMPORTANT]
3333
>
3434
> - Highly accurate time sources
3535
>
36-
> The resulting time accuracy in your topology is highly dependent on using an accurate, stable root (stratum 1) time source. There are Windows based and non-Windows based highly accurate, Windows compatible, NTP Time source hardware sold by 3rd-party vendors. Please check with your vendor on the accuracy of their products.
36+
> The resulting time accuracy in your topology is highly dependent on using an accurate, stable root (stratum 1) time source. There are Windows based and non-Windows based highly accurate, Windows compatible, NTP time sources sold by third-party vendors. Check with your vendor on the accuracy of their products.
3737
>
3838
> - Time accuracy
3939
>
40-
> Time accuracy entails the end-to-end distribution of accurate time from a highly accurate authoritative time source to the end device. Anything that introduces network asymmetry will negatively influence accuracy, for example physical network devices or high CPU load on the target system.
40+
> Time accuracy entails the end-to-end distribution of accurate time from a highly accurate authoritative time source to the end device. Anything that introduces network asymmetry, such as a one-way satellite connection or high CPU load on the target system, will negatively influence accuracy.
4141
4242
## High accuracy requirements
4343

44-
The rest of this document outlines the environmental requirements that must be satisfied to support the respective high accuracy targets.
44+
The rest of this document outlines the requirements that must be satisfied to support high accuracy targets.
4545

46-
### Target accuracy: 1 second (1 s)
46+
### Target accuracy: 1 second
4747

48-
To achieve 1-s accuracy for a specific target machine when compared to a highly accurate time source:
48+
To achieve 1 s accuracy for a specific target machine when compared to a highly accurate time source:
4949

50-
- The target system must run Windows 10, Windows Server 2016.
50+
- The target system must run Windows 10, Windows Server 2016, or a newer version.
5151
- The target system must synchronize time from an NTP hierarchy of time servers, culminating in a highly accurate, Windows compatible NTP time source.
52-
- All Windows operating systems in the NTP hierarchy mentioned above must be configured as documented in the [Configuring Systems for High Accuracy](/windows-server/networking/windows-time-service/configuring-systems-for-high-accuracy) documentation.
52+
- All Windows operating systems in the NTP hierarchy mentioned above must be configured as documented in [Configuring Systems for High Accuracy](/windows-server/networking/windows-time-service/configuring-systems-for-high-accuracy).
5353
- The cumulative one-way network latency between the target and source must not exceed 100 ms. The cumulative network delay is measured by adding the individual one-way delays between pairs of NTP client-server nodes in the hierarchy starting with the target and ending at the source. For more information, please review the high accuracy time sync document.
5454

5555
### Target accuracy: 50 milliseconds
5656

57-
All requirements outlined in the section [Target accuracy: 1 second](#target-accuracy-1-second-1-s) apply, except where stricter controls are outlined in this section.
57+
All requirements outlined in the section [Target accuracy: 1 second](#target-accuracy-1-second) apply, except where stricter controls are outlined in this section.
5858

59-
The other requirements to achieve 50-ms accuracy for a specific target system are:
59+
The other requirements to achieve 50 ms accuracy for a specific target system are:
6060

6161
- The target computer must have better than 5 ms of network latency between its time source.
6262
- The target system must be no further than stratum 5 from a highly accurate time source.
6363

6464
> [!NOTE]
6565
> Run `w32tm /query /status` from the command line to see the stratum.
6666
67-
- The target system must be within 6 or less network hops from the highly accurate time source.
67+
- The target system must be within 6 or fewer network hops from the highly accurate time source.
6868
- The one-day average CPU utilization on all stratums must not exceed 90%.
6969
- For virtualized systems, the one-day average CPU utilization of the host must not exceed 90%.
7070

7171
### Target accuracy: 1 millisecond
7272

73-
All requirements outlined in the sections [Target accuracy: 1 second](#target-accuracy-1-second-1-s) and [Target accuracy: 50 milliseconds](#target-accuracy-50-milliseconds) apply, except where stricter controls are outlined in this section.
73+
All requirements outlined in the sections [Target accuracy: 1 second](#target-accuracy-1-second) and [Target accuracy: 50 milliseconds](#target-accuracy-50-milliseconds) apply, except where stricter controls are outlined in this section.
7474

75-
The other requirements to achieve 1-ms accuracy for a specific target system are:
75+
The other requirements to achieve 1 ms accuracy for a specific target system are:
7676

7777
- The target computer must have better than 0.1 ms of network latency between its time source
7878
- The target system must be no further than stratum 5 from a highly accurate time source
7979

8080
> [!NOTE]
8181
> Run `w32tm /query /status` from the command line to see the stratum.
8282
83-
- The target system must be within 4 or less network hops from the highly accurate time source.
83+
- The target system must be within 4 or fewer network hops from the highly accurate time source.
8484
- The one-day average CPU utilization across each stratum must not exceed 80%.
8585
- For virtualized systems, the one-day average CPU utilization of the host must not exceed 80%.

0 commit comments

Comments
 (0)