All about data units and their application in networking.
A PDU or Protocol Data Unit is an OSI or Open-System Interconnection that is used in telecommunications. It refers to a set of information removed or added by a layer of the OSI model. Every layer in the model utilizes protocol data unit to communicate and exchange information. The information can only be read by the peer layer on the receiving device.
The information is then passed over to the next upper layer after stripping. Protocol data unit is an important term associated to the first 4 layers of the OSI model. On the first layer, protocol data unit is a bit. On the second layer, protocol data unit is a frame.
On the third layer, protocol data unit is a packet. And lastly, on the fourth layer, protocol data unit is a segment. On the fifth layer and higher, protocol data unit is referred to as data. Protocol data unit has 4 fields:
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Destination service access point
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Source service access point
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Control field
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Information field