In this section we will investigate one aspect of a connection-oriented protocol protocol like TCP, which is how a continuous data stream is transmitted from one side to the other. The complicated issues of starting and ending the connection require whole sections of their own and are not addressed herein. Also, we will focus on the situation where one side is the primary sender and the other is the primary receiver, although packets can and must flow in both directions. The transfer of a single file from one computer to another is an example of this type of transmission.