Protocol

In networking, a protocol is the specification of a set of rules for a particular type of communication.

Different protocols often describe different aspects of a single communication; taken together, these form a protocol stack.

The terms "protocol" and "protocol stack" also refer to the software that implements a protocol.

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.

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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.