CNA IOS Upgrade .tar file

Answered Question
Nov 21st, 2007
User Badges:

I recently downloaded CNA and have found it quite useful. I am trying to upgrade the IOS on a router using the software upgrade utility included in CNA. I have read that the utility requires a .tar file and that it completely writes over the flash memory in the router.

I have never used a .tar file before in regards to IOS upgrades. I have always used .bin. Can I download a .tar file from or do I need to create it?

I have read a cisco whitepaper that vaguely described how to create a .tar file, but the syntax in their description did not match up on my router. Any ideas?

Correct Answer by aborole about 9 years 6 months ago

the tar requirement is only for certain switches. You can use the .bin file for routers

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4.5 (2 ratings)
Correct Answer
aborole Wed, 11/21/2007 - 11:43
User Badges:
  • Cisco Employee,

the tar requirement is only for certain switches. You can use the .bin file for routers

zebranutz80 Wed, 11/21/2007 - 11:46
User Badges:

Thank you very much.

Your response brings another question. I utilize a combination of 3750 and 3550 switches. Do I need a .tar file to upgrade them? Do you know if I would need to create the .tar file or it could be downloaded from cisco?

aborole Wed, 11/21/2007 - 13:28
User Badges:
  • Cisco Employee,

for switches which require the tar format, when you download the image from choose the option that includes the "web based device manager". you do not have to create the tar file by yourself.

.tar files are most common in IOS Switches, it's effectively a zipped file with lots of web interface functions and features. When playing with .tar files you would normally use the archive download-sw command, add the /overwrite option and the tar file will be extracted and the old IOS directory/files will be deleted.

With the more common router .bin files, it's a simple copy tftp: flash: command and you can keep the old .bin file or delete it.

In some cases when you have a larger IOS bin image (advipsecurity, and adventerprise for instance), there's not enough room on flash: to copy the second image to so you'll be forced to be very careful in deleting the old image and copying the new image to flash:

We often keep two releases of IOS in flash in our routers, we do this in case there are some unnacceptable bugs in the newer code. If we happen upon an IOS bug, we can reboot to the older, more vetted version and avoid bad things.


This Discussion