A Protocol Data Unit (PDU) refers to a specific unit of data that is exchanged within a network or communication protocol. It represents the smallest amount of data that can be transmitted or received as a whole entity within a particular protocol.
In computer networks, PDUs are used to encapsulate and transmit data between different network components or layers. Each protocol layer has its own defined PDU, which carries certain information or instructions necessary for the protocol to function effectively. PDUs are created by the sender and then processed and interpreted by the recipient according to the rules of the protocol.
The size, structure, and format of a PDU can vary depending on the specific protocol being used. It usually contains a header and a data field. The header contains the control information required to identify the PDU type, sequence numbers, source, and destination addresses. The data field carries the actual payload, which may include user-defined data, commands, or other relevant information.
PDUs are the fundamental building blocks for information exchange in various protocols like TCP/IP, Ethernet, ATM, and many others. They ensure reliable and efficient communication by organizing data into manageable units, enabling error detection and recovery, and maintaining the integrity of transmitted data. By using PDUs, network protocols can effectively manage the exchange of information and provide reliable and secure communication.
