Protocol

A protocol is a rule which guides how an activity should be performed. Formerly used mainly in the diplomatic and government fields of endeavor to denote unwritten guidlines, by the turn of the twenty first century it had come into wide use in the computer and communications fields.

In international law and international relations, a protocol is a treaty or international agreement[?] that supplements a previous treaty or international agreement. A protocol can amend the previous treaty, or add additional provisions. Parties to the earlier agreement are not required to adopt the protocol; sometimes this is made clearer by calling it an 'optional protocol', especially where many parties to the first agreement do not support the protocol.

Some examples: the United Nations Framework Convention on Climate Change (UNFCC) established a framework for the development of binding greenhouse gas emission limits, while the Kyoto Protocol contained the limits later agreed upon.

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Protocol is also a term used in computer science's object-oriented programming.