Configuring a router over a direct connection typically uses which protocol?

When configuring a router over a direct connection, the Trivial File Transfer Protocol (TFTP) is often the protocol of choice due to its simplicity and efficiency in transferring files. TFTP operates over the User Datagram Protocol (UDP) and does not require complex configurations or extensive overhead, making it well-suited for environments where file transfer speed is essential, and robust error handling is less critical.

Using TFTP, network administrators can upload or download configuration files and firmware to and from routers. This is particularly useful during initial router setup or when applying updates, as the protocol allows for straightforward deployment of these files without needing a full FTP client—reducing complexity and streamlining the process.

Other options such as FTP, DHCP, and ARP serve different purposes in network operations. FTP is more complex, includes features like authentication, and is generally used for more substantial data transfer tasks. DHCP is employed for dynamic IP address allocation, not for configuration file transfers. ARP is a networking protocol used for mapping IP addresses to MAC addresses within a local network, which also does not relate to router configuration tasks. Thus, TFTP is distinguished as the most appropriate protocol in this scenario.