Clarity on Bug: CSCub12922 | Adding a new subscriber causes device reset

Mohit Grover · ‎07-22-2015

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Clarity on Bug: CSCub12922 | Add a new subscriber to existing 8.x CUCM cluster causes all device reset

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When we add a new node to an existing cluster, all phones that are registered to the cluster are reset.

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The condition is applicable only to CUCM 8.6 and higher releases.
Whenever a node is added to CUCM cluster, from CUCM 8.6 onwards, the phones which belong to that Call Manager group will be automatically restarted.
"Its not a bug", its the default behavior."

This is more of a functionality on CUCM version 8.6 and above rather than a defect.
This functionality will let CUCM restart devices as soon as a new node is added to the cluster.

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!! Here is why it happens !!

CUCM 8.6 and above versions send out ITL certificate to endpoints.
ITL certificate's have the information about the call manager nodes of the cluster.
As soon as we add a new node to the cluster, call manager updates the DB with its entry.
With this defect/functionality, CUCM also updates ITL certificates at the same time and sends out restart signal to the phones so that they can download updated ITL certificate.

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Workaround: None

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!! Here is when it happens !!

I added a Subscriber to an 8.6.2.20000-2 Cluster and was able to replicate the issue, the reboot happened during the final stages of the installation of CM node.

Completion of the Sub's installation was at 12:37 with the reboot of the phones occurring at 11:55.

!! Would it be a Hard Reset or Soft Reset !!
These reset's are soft reset's, which means that if there is an active call it WILL NOT reset the endpoints (while the call is active)
>
It will only reset devices that are idle.

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You may contact me at Mohit.Grover@cisco.com

Mark VandeVere · ‎08-29-2016

I can challenge the final assertion that it will only reset devices that are idle.

I added a Sub to our 9.1(2) cluster last week. It reset every phone, and from end user reports, it dropped every active call. This is not a huge deal once you know the reality. Not knowing it is a huge deal. This is no longer done prime time hours!