New Subscriber Addition - Impact ?

[dryliciouz]

Hello,

We currently have CUCM cluster with around 10,000+ users.

We are planning to add a new CUCM Subscriber to our exising Production environment.

This new sub will not run a CM service and only for IPVMS purpose.

I have read somewhere in the forum that during the installation of Sub, there will be a reset in all phones?

I just want to verify if this is still happening in 11.5 version as we want to avoid an impact,eventhough we will done during maintenance window.

Our CUCM version is 11.5 SU(5)

Thanks & Regards,

Andry

[Vinod.s]

I did and all phone restarted .
Please take Downtime or perform this in off business hr.

[George Sotiropoulos]

Hello,

The reset of the phones, upon adding a Subscriber is an expected behavior, you can have a look below:

https://community.cisco.com/t5/collaboration-voice-and-video/clarity-on-bug-cscub12922-adding-a-new-subscriber-causes-device/ta-p/3160426

George

[dryliciouz]

Hi George, 

Thanks for reply.

When does the restart of the phones happens? Is it during the installation?

Is it apply to all subscriber? I just curious as I won't add Subscriber to CUCM Group as it's only run IPVMS.

Thanks.

[George Sotiropoulos]

If i remember correct, the restart occurs at the phones that below on the CM Group that includes the New Subscriber and its a soft-restart, ie if a phone is on a call, this phone will restart only when the call ends.

All the phones at this CM Group will restart, since the Publisher will send a restart prompt to the phones, to get updated with the new ITL file that includes -amongst other- info for the new Sub.

G

[dryliciouz]

Hi George,

Thanks for reply.

That means if i'm not adding to the CUCM Group, it won't impact the phones?
As mentioned before this Call Manager service will not be activated for this subscriber.

[Chris Deren]

The phone reset has nothing to do with the CUCM configuration itself but rather updates to the ITL files when new node joins the cluster.  Phones will reboot during the CUCM sub install process, so be ready for the phones to reset and plan accordingly.

[George Sotiropoulos]

Chris is totally right, I was going to mention that my previous comment was not totally correct.

Chris thank you for clarifying.

George

[Chris Deren]

Thanks George.

Just as a point of reference this was introduced in CUCM 8.5 or 8.6, in prior versions you were able to add CUCM node with no impact to the cluster (good ole days :0) 

[George Sotiropoulos]

I would suggest to do it off hours.