How to Upgrade a Cisco IOS


Upgrading a Cisco IOS may seem a bit awkward at first, but with a little trial and error you’ll find that it’s not as difficult as it may initially seem.


First things first, here is what you’ll need.


1.) Console Cable

2.) Ethernet Cable

3.) Latest version of the IOS for the model of Router or Switch your upgrading.

4.) TFTP Server Software –  Download Here!

5.) Terminal Emulator/Telnet Client – like Putty! – Download Here! 


Getting Started

To get the ball rolling you’ll need to ensure you’re connected to your router or switch correctly.  There are a couple types of cables available to achieve this. The most common is the serial port to RJ45 cable or USB to RJ45. Another cable that can be used on the newer Cicso unites in the USB – A to USB – mini B. The ports you have available on you connecting PC will determine which cable you should use.


Plugging in

Once you have the correct console cable for you system it’s times to plug in.  Most Cicso devices have the RJ45 port but some newer systems from Cisco have the USB mini port as well. Also be aware that most Cisco devices color code the console port in light blue. Be ware you will not have access to the device if you plug into any of the other ports.


Next plug in the Ethernet cable from the PC to the router. This is required to upload the new IOS from your TFTP server to the device your upgrading.

The diagram below is what your cable routing should look like like.



Now that your all plugged in and you have your Telnet client and TFTP server software installed you are ready to initiate the IOS upgrade.


Setting up a TFTP server.


To set up your TFTP server you’ll need to change your IP4 settings on your local machine. This part can be tricky as there is some confusing information out there. First access your local Area connection and change the IP4 setting as follows.




Open your TFTP client and bind the TFTP server to the above IP



Create a TFTP directory folder and place the IOS bin in the folder.


In the TFTP client select the bin you wish to use to upgrade your Ciso Router/Switch.

Nest you’ll use the IP as part of the setting from rommon. Enter the commands as follows.




After update is complete enter boot command.


Once booted enter show flash command and then copy run start to save setting.


Your Cisco IOS is now up to date.



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