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Upgrading Phone Firmware: Is Install on PUB Required vs Only Nodes Running TFTP?


Kindly assist me with the below.

When installing a new firmware file on a CUCM cluster should I always install it on the PUB and TFTP subscribers, or can I simply install it on the TFTP subscribers?

I will be using the cop install method. Our PUB does not run TFTP services. We have two dedicated subscribers running TFTP services. 


What is the Cisco recommended and approved process? What is best practice? Does Cisco support installing the firmware only on TFTP nodes?

L. K. | Consultant, Lead Senior Engineer, Specialist | Cisco Unified Communications
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That is incorrect. Individual firmware files, or the COP files, DO NOT need to be installed on the PUB, or any NON-TFTP subsequent SUB, MOH nodes. Regular phone specific new firmware versions/updates need only to be applied to the TFTP nodes. This can be done via COP install (preferred) or manually via the ZIP contents.


This method also helps reduce the unnecessary file management and storage used on the clusters' nodes, as well as decreases the DRS size.


The only time this is required on PUB (and potentially rest of the cluster) is when installing Device Packs*.

* There may be very rare cases where the new individual firmware adds/removes/updates CUCM code for configuration of a new feature within CUCM that is phone specific which may require it be installed on PUB and all nodes on cluster (e.g. a new phone specific configuration line item within CUCM Device page). From my research this is extremely rare, and pointed out within the release notes/read-me. If unsure can always reach out to TAC to inquire about this. I have not come across this situation yet, and Cisco informed me these kind of firmware updates are typically deployed within Device Packs.


L. K. | Consultant, Lead Senior Engineer, Specialist | Cisco Unified Communications

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Chris Deren
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Technically firmware files are only needed on the TFTP nodes as those are the only nodes that will serve them.  Installing it on the Pub allows it to change the device defaults page, plus it's a good idea to keep the files consistent in case you at some point decide to turn on TFTP service on other nodes if TFTP node goes down, etc. I always install firmware files on all nodes even on large multi-node clusters with only 2 TFTP nodes in the cluster, does not take that much more time, especially if you use PCD to install it or use automated tool (I built one to push files directly to TFTP store).

Thanks for the response.


That is typically what I have done in the past. Currently this cluster is very large, PUB, 8 CM SUBs, 2 TFTP SUBs, 2 MOH SUBs. They ran into issues with DRS backup size from firmware files on all nodes and only want to install on the TFTP SUBs manually.


Would you know any specific details on what the COP install files actually does? Does the COP file simply only extract the firmware loads, and update the device defaults if it is installed on a PUB? Does it do anything additional at all beyond that?


Are there any negative sides to NOT installing it on the PUB, and only the TFTP SUBs?


Also @Chris Deren I am very curious about your automated tool you built (to push files directly to TFTP store). Would you be willing to share this with me? Or at the code please? I would greatly like to look into this and would be much appreciated.


Thanks again!



L. K. | Consultant, Lead Senior Engineer, Specialist | Cisco Unified Communications