Backup Process of the Cisco IOS

Step 1: Checking the Router’s IOS filename:

Router#show flash:

Step 2: Checking the Server’s TFTP Service: 

Go to the Services Tab and then click 
on the TFTP tab available on the list.

Step 3: Verifying Reachability from Router to Server: 

Router#ping 10.0.0.2

Step 4: Copy the Router’s IOS to the TFTP Server: 

Router#copy flash: tftp:
Source filename []? 2800nm-advipservicesk9-mz.151-4.M4.bin
Address or name of remote host []? 10.0.0.2
Destination filename [2800nm-advipservice
sk9-mz.151-4.M4.bin]? Router-IOS.bin

Step 6: Verifying if IOS has been copied to the TFTP Server: 

Go to the Services Tab and then click on the TFTP tab to
check if our IOS Destination filename is present on the list.

Now, our Router’s IOS has been copied. Before starting the Recovery Process, we must delete our IOS first.

Router#delete flash:
Delete filename []?2800nm-advipservicesk9-mz.151-4.M4.bin
Delete flash:/2800nm-advipservicesk9-mz.151-4.M4.bin? [confirm]y 
Router#reload
System configuration has been modified. Save? [yes/no]:no
Proceed with reload? [confirm]y

As you can see, the IOS file stored in the Flash memory has been deleted and the Boot Process has failed. This failure of the Boot Process when the Router fails to load the IOS from Flash makes the Router go into ROMMON mode.

Cisco IOS is just like any other operating system and is used by routers and switches or other Cisco networking devices. Cisco IOS is a single image file that is stored in the flash memory in the case of Routers. When these routers are booted (powered on), the IOS stored in the Flash memory is loaded into the RAM.  If there is no IOS available in the Flash memory of the Router, the Router simply enters the ROMMON mode which allows us to install the IOS image file again. For the Backup process, we will be using TFTP (Trivial File Transfer Protocol). There is no need to go in depth of what TFTP really is or how it works, just know that it is a UDP-based file-transferring protocol used to read and write files from a remote server. Using TFTP, the transfer of files starts with a request to read or write files after requesting a connection. These file transfers take place only when the server grants the connection request.