This is a list of the world's largest armies, measured by the number of soldiers in uniform. This is not a list of the world's strongest armies, since military power is not simply a function of headcount.
Protocol is defined as the rules and customs of a group or a standard procedure. An example of protocol is the method by which a learning center must document their students' progress. YourDictionary definition and usage example.
Address Resolution Protocol - a network layer protocol that translates numeric IP addresses into equivalent MAC layer addresses necessary to transfer frames from from one machine to another on the same cable segment or subnet.