ISR 4331 network-clock synchronization automatic added on reboot

[Jim Matuska]

On a ISR 4331router every time I reboot it adds the

network-clock synchronization automatic

command to my configuration even though I put in the

no network-clock synchronization automatic

configuration and saved before reboot.  This is really annoying since I need to have this disabled in order to allow me to synchronize the router with the T1/PRI port from my voice carrier using the

network-clock input-source 1 controller T1 0/1/0 and clock source line primary

(under my controller T1 0/1/0) configuration.  

Without clocking to the telco I get slip seconds incrementing on the T1 controller.  

Is this some sort of bug?  I am running version isr4300-universalk9.17.06.01a.SPA.bin

I have ruled out my callmanager servers causing this configuration change by removing the

ccm-manager config

command from my configuration and rebooting and it still adds back the clock auto synchronization.  

Any thoughts?  

[M02@rt37]

Hello @Jim Matuska 

It's possible that the addition of the

network-clock synchronization automatic

command to your configuration after reboot is a bug in the ISR 4331 router software.

As I concerned, I've created an EEM script that runs automatically upon boot and removes the

network-clock synchronization automatic

command from the configuration. This script is triggered by a specific event, such as the completion of the boot process or the detection of the clock synchronization command in the configuration.

[Jim Matuska · Accepted solution]

I really don't want to have to build a script for a workaround to a potential bug, but I did find a solution to keep my PRI's from getting slip seconds incrementing and using the

network-clock synchronization automatic

so my configuration doesn't change on reboot.  For reference both the old and new configurations below work for our PRI voice circuit and don't give any clocking errors on the PRI but the only problem with the old configuration is that it adds the

network-clock synchronization automatic

command on reboot.  

Does anyone see any issues with the new configuration?  

Old Config
controller t1 0/1/0
clock source line primary

no network-clock synchronization automatic
network-clock input-source 1 controller T1 0/1/0


New Config
controller t1 0/1/0
clock source line primary

network-clock synchronization automatic
no network-clock synchronization participate 0/1
no network-clock input-source 1 controller T1 0/1/0