PDU (Protocol Data Unit)

A Protocol Data Unit (PDU) is a standardized block of data that is transmitted across a network, structured according to specific communication protocols. It encompasses the actual information being sent along with necessary control data, such as headers and addresses, to ensure proper delivery and interpretation. Different layers of a network stack (like application, transport, and network layers) have their own types of PDUs, customized to handle their specific functions. Think of a PDU as the "package" of data exchanged between devices, containing both the message and the essential information to guide its journey through the network.