Cisco IOS is the operating system that runs on Cisco routers and switches, providing features and functions for network connectivity, security, and management.
TFTP (Trivial File Transfer Protocol) is a simple and lightweight protocol that facilitates file transfer between devices over a network. It is commonly used to upload Cisco IOS images to Cisco devices, such as routers and switches.
To upload Cisco IOS via TFTP, you need the following:
A TFTP server running on a computer connected to the same network as the Cisco device. You can use software like SolarWinds TFTP Server or TFTPD32.
A Cisco IOS image file compatible with your Cisco device, which you can obtain from the Cisco website or other sources.
A console cable to connect your computer to the console port of the Cisco device. Use a terminal emulator software like PuTTY to access the device’s console.
Connect your computer to the console port of the Cisco device using the console cable. Launch the terminal emulator software and configure the serial port settings, such as baud rate, data bits, parity, stop bits, etc., according to your device specifications.
Power on your Cisco device and press Ctrl + Break or Ctrl + C on your keyboard to interrupt the boot process and enter the ROM monitor mode. You will see a prompt like rommon 1 >.
Set the IP address of your Cisco device and the TFTP server using the following commands. For example, if your Cisco device IP address is 192.168.1.1 and your TFTP server IP address is 192.168.1.100:
rommon 1 > IP_ADDRESS=192.168.1.1
rommon 2 > IP_SUBNET_MASK=255.255.255.0
Set the default gateway of your Cisco device using the DEFAULT_GATEWAY command. For example, if your default gateway is 192.168.1.254:
rommon 3 > DEFAULT_GATEWAY=192.168.1.254
Set the name and location of your Cisco IOS image file using the TFTP_FILE command. For example, if your Cisco IOS image file name is cisco-ios.bin and it is located in the root directory of your TFTP server:
rommon 4 > TFTP_FILE=cisco-ios.bin
Set the destination of your Cisco IOS image file on your Cisco device using the TFTP_SERVER command. For example, if you want to upload your Cisco IOS image file to the flash memory of your Cisco device:
rommon 5 > TFTP_SERVER=flash:
Start the upload process using the tftpdnld command. You will see a confirmation message like “Invoke this command for disaster recovery only. Type Y and press Enter to proceed.”
rommon 6 > tftpdnld
Wait for the upload process to complete. You will see a message like “Download Successful.” Type reset and press Enter to reboot your Cisco device with the new Cisco IOS image.
Uploading Cisco IOS via TFTP is a method of updating or restoring the operating system of your Cisco routers and switches. This process requires a TFTP server, a compatible Cisco IOS image file, and a console cable to access the device’s console. By configuring specific parameters on your Cisco device and using the tftpdnld command in the ROM monitor mode, you can enhance or recover the functionality of your Cisco devices.