When downloading a firmware image to a Cisco UCS Fabric Interconnect, especially from a remote location, it is crucial to use a protocol that provides both encryption and authentication to ensure the security and integrity of the file transfer. HTTPS (Hypertext Transfer Protocol Secure) is the protocol that meets these requirements. It is widely used for secure communication over a computer network within a web browser, with encryption provided by Transport Layer Security (TLS), which ensures that the transfer of the firmware image is secure and authenticated1. References: * Cisco UCS Manager Firmware Management Guide, which provides detailed instructions on managing firmware through UCS Manager, including downloading firmware images to the Fabric Interconnect