In packet switching, header (header) is called that part of the packet, or more generally the PDU, which contains control information required for network operation, i.e. layered layer protocol information (PCI) as opposed to payload (SDU) or to useful data that is transported between network users. Describe the wikitesto modification
The header is normally placed at the beginning of the package; if it is placed at the end, the header is called the trailer (queue). The header bit length is always fixed, unlike the payload (data) of the packet, which, depending on the protocol level, may vary. In transmission, each layer adds its header to the initial payload; in receiving each protocol layer, inverse, extracts and analyzes the respective header by performing the processing or control capabilities on the transmitted and received packet. Typically, the package header of each architectural layer protocol consists of one or more data fields, each with a specific meaning or functionality.
In a sense, it can be said that the overhead (load) additional information owing to the packet header or PCI is the very essence of the telematic networks in terms of architecture: in fact, they all associate functions / processing operations and receiving control to achieve efficient and reliable communication between two network processes. Notemodify wikitesto
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