Certifications / Cisco

How to Upgrade to Call Manager 12.5

by Team Nuggets
How to Upgrade to Call Manager 12.5 picture: A
Published on November 25, 2021

Upgrading Cisco Unified Communications Manager (CUCM) to 12.5 can be a difficult decision. It is definitely worth it, but takes time and can be challenging. Once that decision has been made, having a step-by-step guide that is easy to follow is extremely important.

The first item on the list is verifying that the licensing has either been converted to FLEX, which automatically adds the licenses to the Smart License Manager at Cisco, or the CUWL licenses have been converted to the Smart License Manager. Our suggestion is to take a look at FLEX and what it can do for you.

What the Upgrade Look Likes and How Long it Takes

I'm not going to sugarcoat it. This is a major upgrade and will take about 2.5 hours for the Publisher servers and 1.5 to 2 hours for the subscribers. First, you need to make sure that your hardware is ready for the upgrade. CUCM 12.5 requires VMWare ESXi 6.5 or higher. So, if you are on a UCS server you may need to upgrade the firmware, as well as upgrade the VMWare prior to the CUCM upgrade.

Cisco provides a website to help you determine if your hardware can do this and what firmware you may need. You will need to put in your Server Type, Model, Processor version, Operating System, OS version.

Pre-Upgrade Tasks

There are some pre-upgrade tasks that you will want to do to prepare for the upgrade. Cisco has a pre-upgrade cop file to run for both CUCM and Unity Connection that will tell you if your server is ready for the upgrade. The filename is ciscocm.preUpgradeCheck-00024 and can be found in the Software Downloads section of Cisco's website.

The cop file checks disk space, NTP, Network connectivity, etc. Mostly, there will be disk space issues as this upgrade takes more space than previous upgrades. When that is the case, run the ciscocm.free_common_space_v1.5.cop.sgn file to free up the necessary space. At times, even that does not free up enough space, so it is possible to remove some phone firmware for specific devices that the system is not using to free up a little more space.

The next step is to verify that the virtual hardware for each of the servers matches the current 12.5 ova templates. This is important as the switch-version at the end of the upgrade checks to make sure this hardware is correct. If it does not match it will fail. Therefore, check the Hard Disk, Ram, Network adapter, etc., and make sure it is the same as the ova template. If you need to make any changes it will require a shutdown of the server to make the change in Vmware ESXi.

Here are the latest virtualization specifications for CUCM, CUC, IM&P, and UCCX.

Performing the Upgrade

Finally, the upgrade to 12.5 can begin. Upgrade the CUCM Publisher first. The Unity Connection and UCCX Publishers can also be done at the same time to save time. The IM & P Publisher will need to wait until the CUCM Publisher is done as it is considered a subscriber to the CUCM Publisher. Once the publishers are done all of the subscribers can be done at the same time. If you have multiple subscribers that phones are registered to and you want to reduce downtime the subscribers should be done one at a time.

You can choose to switch versions automatically after the upgrade or wait until all are done. The Unity Connection does not give you that choice and switches automatically. UCCX also does not give you the choice but you have to do it manually.

There are three ways to accomplish the upgrade. The upgrade can be done through the Prime Collaboration Deployment Server. This server can be deployed on the ESXi and takes minimal configuration. However, not all of the applications can be done through the PCD. In some cases it can be easier as it can do the whole cluster one by one. However, there is a chance that you will run into problems which will make it necessary to restart the upgrade manually anyway.

The second option for the upgrade is to use the GUI in OS Administration. The problem with using the GUI for a major upgrade is that the server needs to reboot and the GUI cannot follow the upgrade after the reboot. Therefore, you will need to go into the CLI and watch the install logs to verify when the upgrade has finished.

Many collaboration engineers prefer the CLI when performing this upgrade. Bring up the console on the VMware ESXi and login. The command to begin the upgrade is "utils system upgrade initiate. The prompts will ask to use an SFTP server or local disk image. The best option is to upload the image to the datastore and mount it to the DVD drive and choose the local disk image. It will reach out and find the image and verify the compatibility. On the CUCM it will ask if the switch-version should take place automatically after the upgrade. Once you confirm the upgrade begins.

Now it's time to go get a sandwich or something because the waiting game has begun. As stated above, all the Publisher servers can be started at the same time and will take 2 to 2.5 hours. Then, the Subscribers/IM&P Publisher can be started. In all it may take 2 to 3 rounds of upgrades to finish.

Post-Upgrade Tasks

If the switch-version did not take place automatically for the CUCM after the upgrade, it is now time to take care of that. On the CLI the command is "utils system switch-version". With that command the server will reboot and as it comes back up it will copy the database from the active partition to the inactive and make the inactive partition active. The only difference here is with the UCCX server. It goes through a nine step process which you see on the CLI and then reboots.

Next is to make sure that the hardware version of each virtual machine in the ESXI is upgraded. To do this, shut down the virtual machine, starting with the CUCM Publisher. Once it is down the option to upgrade the hardware version will be available. Restart the virtual machine. When the server comes back up the VMware tools should upgrade automatically.

How to Register Publishers Using Smart License Manager

To register the publisher go to https://software.cisco.com, login and click on the link under Smart Software Manager called Manage licenses. Click on Inventory and then New Token. The number of uses of this token and how many days it lasts can be specified. If you have all the applications in the UC Suite you will want to make at least three uses. Now, in CUCM go to system>>Licenses and click on the Register button. It will ask for the token you just created on the Smart License Manager. Once done, you will be able to see the licenses consumed on the Smart License Manager.

Testing All Functionality

At this point, it is very important to make sure all of the phones have registered, and you will want to check the following:

  1. Inbound and outbound calls.

  2. Unity Connection voicemail and call handlers

  3. Transfers and conferences

  4. Logging into the Finesse Desktop

  5. Calls into UCCX

  6. Any other functionality that is important to your business

The Upgrade is Complete

And now the upgrade is complete. Give yourself a big pat on the back because that was quite an ordeal. But you came through with flying colors! We hope that this upgrade guide has been helpful in some way in your upgrade project. We know how difficult it can be and having a guide from those who have been through it before is like having a collaboration engineer right by your side.


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