WHAT "STANDARD" MEANS ?

Agreements must be at many levels ... How many volts pulse is a 0 and 1? How to determine the end of a message? How to handle lost messages? How many bits for different data types? Integers/Strings, etc. Are characters coded in ASCII ? How machines are identified in a network? Names, numbers ? How to find the way to reach a machine ? How if there are more choices ? How different applications (and OSs) speaks together through the network ?