Certifications / Cisco

How to Upgrade to Call Manager 12.5

by Team Nuggets
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Published on November 25, 2021

Upgrading Cisco Unified Communications Manager (CUCM) to 12.5 can be difficult. It is worth it, but it 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 Looks Like and How Long It Takes

I'm not going to sugarcoat it. This major upgrade will take about 2.5 hours for the Publisher servers and 1.5 to 2 hours for the subscribers. First, you must ensure 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 and 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 enter your Server Type, Model, Processor version, Operating System version, and OS version.

Pre-Upgrade Tasks

You will want to do some pre-upgrade tasks 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 removing some phone firmware for specific devices that the system is not using is possible to free up a little more space.

The next step is to verify that each server's virtual hardware matches the current 12.5 OVA templates. This is important as the switch version checks at the end of the upgrade 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, the server will need to be shut down 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 simultaneously 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 subscribers can be reached simultaneously. If you have multiple subscribers that phones are registered to and want to reduce downtime, the subscribers should be able to do so one at a time.

You can switch versions automatically after the upgrade or wait until everything is 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, which can be deployed on ESXi and requires minimal configuration. However, not all 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 must 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 log in. The command to begin the upgrade is "utils system upgrade initiate.

The prompts will ask for an SFTP server or local disk image. The best option is to upload the image to the datastore 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 get a sandwich because the waiting game has begun. As stated above, all the Publisher servers can be started simultaneously 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 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, we need to ensure 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, log in, and click on the link under Smart Software Manager, 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 created on the Smart License Manager. Once done, you can 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 is like having a collaboration engineer right by your side.


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