Field Notice: FN74423 - Enhancing SyncE/PTP Clock Recovery Reliability for Cisco 8712-MOD-M Units - Software Upgrade Recommended

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Updated:July 30, 2026
Document ID:FN74423

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Medium
Impact Rating:
Medium
First Published:
2026-Jul-30
Last Published:
2026-Jul-30
Revision:
1.0
Cisco Bug IDs:

Notice

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected


Affected Product Name Description Comments
8712-MOD-M Cisco 8712 2RU 6.4T K100 System with 4 MPA bays  




Defect Information


Defect IDHeadline
CSCwt801528712-MOD-M: Disable 12x MDCs output clocks by default for SiliconOne K100

Problem Description


As part of ongoing quality assurance and product monitoring, Cisco has identified a configuration-specific optimization for the recovered clock functionality on Cisco 8712-MOD-M units. 


Background


The Cisco engineering team has identified potential performance sensitivity in the Synchronous Ethernet (SyncE) clock and Precision Time Protocol (PTP) functions. This sensitivity is linked to the interaction between the Network Processing Unit (NPU) clock and the system timing function. As a preventive measure, Cisco is providing a software update that improves timing function robustness and mitigates the potential impact of the performance sensitivity.


Problem Symptom


Customers who are utilizing the SyncE and PTP functionalities may experience intermittent timing reference qualification issues with SyncE and PTP clock recovery. In these cases, synchronization performance of the Cisco 8712-MOD-M unit may be affected.


Workaround/Solution


Customers Who Are Using SyncE and PTP

Customers may upgrade to Cisco IOS XR Release 26.1.2 or later. Alternatively, the following SMUs are available for deployments that require an update without upgrading to a new software release. Cisco recommends installing the appropriate SMU to improve the robustness of recovered clock operations and ensure reliable timing synchronization.

IOS XR Release SMU SMU Type
IOS XR Release 25.3.1 8000-25.3.1.CSCwt80152.tar Reboot
IOS XR Release 25.4.2 8000-25.4.2.CSCwt80152.tar Reboot
 

Customers Who Are Not Using SyncE or PTP

No immediate action is required if a deployment does not utilize SyncE or PTP functionality. Installation of this software update is optional.


Revision History


VersionDescriptionSectionDate
1.0Initial Release—2026-JUL-30

For More Information

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