Cisco 3850 – Upgrading IOS XE from 3.x.x to 16.x.x
- First, we will need to copy the new software to the flash on the switch. This can be done with either copying from a USB drive or TFTP server. I am using TFTP since I don’t have direct access to the switch.
| copy tftp: flash: |
We can check the flash to verify that the new software is present
| show flash: |
NOTE: You can increase the TFTP block size to increase the transfer speed.
To increase the block size enter the command below in configure terminal
| ip tftp blocksize 8192show flash: |
- Second, we need to Regenerate RSA crypto keys before the upgrade.
| crypto key generate rsa general-keys modulus 1024 |
- Now we are ready to upgrade the switch. Before we run the upgrade command, let’s verify how many switches are in the stack:
| show switch |
In my case, there are four active switches so I will run the following command
| software install file flash:/ cat3k_caa-universalk9.16.06.05.SPA.bin switch 1-4 verbose new force |
If you have 3 switches for example change the switch 1-4 to switch 1-3
After, we run the command we will be prompted with a couple of questions:
Do you want to proceed with reload? [yes/no]:yes
System configuration has been modified. Save? [yes/no]:yes
The switch will reboot, and the upgrade begins, it will take approximately 15-20 mins
– After the switch comes back up, we can confirm that all switches are upgraded
| show version |
Now we can run the following command to clean up the old packages from the flash and free up some space
| request platform software package clean switch all file flash: |