AFP stands for Apple Filing Protocol. AFP uses TCP port 548.
Similar to how Windows has its own protocols for file transfer, MacOS also has it’s own protocol, AFP, for file transfer.
AFP supported file sharing between Mac computers on early LANs
AFP works with SLP (Service Location Protocol) – TCP 427 and UDP 427 – to view a list of available servers/devices.
AFP provides support for full file management including the ability to copy, move, and delete files.
Windows lacks support for this protocol.
AFP is being deprecated in favor of SMB using TCP Port 445.