A uniform set of rules that enable two devices to connect and transmit data to one another. Protocols determine how data are transmitted between computing devices and over networks. They define issues such as error control and data compression methods. The protocol determines the following: type of error checking to be used, data compression method (if any), how the sending device will indicate that it has finished a message and how the receiving device will indicate that it has received the message. Internet protocols include TCP/IP (Transfer Control Protocol/Internet Protocol), HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), and SMTP (Simple Mail Transfer Protocol).