Upgrade Cisco IOS on Cisco 6500 in VSS mode

If you are using the old Cisco 6500 probably as me need to upgrade the IOS o e new version. Usually I don’t want to upgrade core routers but due to a BUG we had to do it.

The router we had is a Cisco 6509 and it’s working with two SUP 720 Supervisors and we had problems with NetFlow sampling with the current version that we had(122-33.SXI6). When we implemented the VSS mode we disabled the mls sampling command which was found in this BUG: https://bst.cloudapps.cisco.com/bugsearch/bug/CSCtk63049

Now we need to enable NetFlow and without sampling we have overload problems. If you want to read more about it here is a link how to do it: NetFlow Sampling on Cisco 6500 & 7600 series device

Now that we have to upgrade the IOS here is the procedure how to do it:

  1. Copy the IOS to primary supervisor card using the command “copy tftp:/IOS.bin sup-bootdisk:”
  2. Copy the IOS to the SECONDARY supervisor card using the command “copy tftp:/IOS.bin slavesup-bootdisk:”
  3. Remove the old boot variable string using the command “NO boot system flash sup-bootdisk:OLD_IOS.bin”
  4. Add the new IOS file to the boot variable string using the command “boot system flash sup-bootdisk:NEW_IOS.bin”

Now you should have the new IOS running on your Cisco 6500. In our case we have upgraded the IOS image and enabled NetFlow sampling and we can now have better monitoring for our router.

I hope this will help you upgrade your IOS on your Cisco 6500 router.

Nikola Stojanoski

System Administrator and Developer. Giving back to the community by blogging about my problems, solutions and practical howto's.