The Internet utilizes a set of networking protocols called TCP/IP. The applications protocols that can be used with TCP/IP are described in a set of Internet Engineering Task Force (IETF) RFCs (Request For Comment). These documents describe the "standard" protocols and applications that have been developed to support these protocols. Protocols provide a standard method for passing messages. They define the message formats and how to handle error conditions. Protocols are independent of vendor network hardware, this allows communication between various networks with different hardware as long as they communicate (understand) the same protocol. The following diagram provides a conceptual layering diagram of the protocols..