Protocol Data Units (PDU's)

A protocol data unit is a term used in much of the documentation and educational literature for networking technologies. It simply means a chunk of data created and/or labled by a particular protocol. TCP, UDP, IP, OSPF and RIP (and other protocols) could be said to create "protocol data units". The term is somewhat synonymous with packet or frame, especially when used in the process of discussing routing protocols or spanning tree.