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!
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.
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.