Internetwork Protocol
In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication.
Multiple protocols often describe different aspects of a single communication. A group of protocols designed to work together are known as a protocol suite; when implemented in software they are a protocol stack. The terms are often intermingled; people may use the term "protocol" to refer to a software implementation, or use "protocol stack" to refer to the specification.
Most recent protocols are assigned by the IETF for Internet communications, and the IEEE, or the ISO organizations for other types. The ITU-T handles telecommunications protocols and formats for the PSTN. As the PSTN and Internet converge, the two sets of standards are also being driven towards convergence.
Read more about Internetwork Protocol: Network Protocol Design Principles, Protocol Families