With the Scheduled Transfer Protocol (STP), the receiving node can build up buffer capacity before data transmission without having to integrate the host 's operating system. The receiving side buffer is managed by the sending node. This involves establishing validated ports via virtual control channels. Data is again transmitted directly to the receiving node's memory via virtual channels. The STP protocol supports data transfer with data packets (STU, Scheduled Transfer Unit) of up to 4 gigabytes ( GB) in size. Up to `2^48` of such data packets can be transferred with one data transfer.