suitable for transmission or processing by the lower layer, a process known as IP fragmentation.

The significance of this is that the PDU is the structured information that is passed to a matching protocol layer further along on the data's journey, which allows the layer to deliver its intended function or service. The matching layer, or peer, decodes the data to extract the original service data unit, decides if it is error-free and where to send it next, etc. Unless we have already arrived