Protocol A protocol is a standard - an agreed-upon format - for the exchange of data between two computers (or other devices). Protocols define standards on various levels – from methods for error checking and data compression to the format of e-mail messages. Programmers can choose among various protocols with various advantages and disadvantages. A protocol can be implemented in hardware as well as software. A computer must support the right protocols if the user wants to communicate with other computers, e.g. on the Internet. Examples of protocols are: HTTP for the transfer of Web documents, FTP for file transfer, and SMTP for e-mail.
