What three requirements are defined by the protocols used in network communications to allow message transmission across a network

"message encoding, message size and message delivery" are the correct answer for the above question.

Explanation:

The above defined are the three requirements which are defined as the protocol used in communication. These three requirements are a very essential part of communication because-

Message Encoding is the first requirement, which is used to encode the message so that the hacker can not hack the communication data from the network.The second requirement is Message size which fixed the size and the number of packets used to send for the communication.The third requirements are Message delivery, for which the protocol needs to define the mechanism to overcome the loss of the data.