Cisco IOS

[cknox1]

hello everyone,

Please can somebody help with the general rule for choosing the best IOS to upgrade to? I can find out what the latest ones are for my devices, but how do you know which is the preferred one to upgrade to and how often should you upgrade.

Please let me know.

Thank you

[Martin L]

they will show you option of suggested versus the latest one; but you can choose which one you want.  log in and go to downloading page , example 

https://software.cisco.com/download/home/286309062/type/280805680/release/15.2.7E1

[Martin L]

move the mouse over the Yellow start to see why

[Leo Laohoo]

1. Read the Release Notes carefully.
2. Look at the Release Date of the firmware. Do not use any firmware that are >6 months old.
3.  Look at the version number:  

• For "classic" IOS, an example, 12.2(55)SE10; 
• For IOS-XE, an example, 16.6.9

Look at the last digit - For "classic" IOS, last digit is "10" and for IOS-XE, the last digit is "9".   Use firmware versions with a very high "last digit".  Rule of thumb:  Last digit is "4" and higher.  

4.  If the last digit is a number and followed by a letter, example, 16.12.1b, AVOID.  

[cknox1]

Hello thank you for reply! why must we avoid firmware with letter at the end?
Also, so it is the case that we are just using our best judgement on the latest release - so no difference on release such as Fuji or Denali just different names.

Also just to confirm the difference between bin file and IOS is:
- Bin is the switch software
- IOS is switch firmware?

Thank you for your help

[Leo Laohoo]

IOS = Internet Operating System.
BIN = file extension

[cknox1]

So the BIN file can be classed as the software?