Encapsulation of PDUs

Encapsulation or layering is the addition of Protocol Control Information (PCI) to a Protocol Data Unit (PDU) by a communications protocol. The encapsulation adds headers before the start of a PDU.

Encapsulation of a SDU by adding a PCI to form a PDU

Encapsulation takes place at each layer of the OSI reference model, and to explain encapsulation OSI defines the concept of a "service" and a Service Data Unit (SDU).

Gorry Fairhurst - Department of Engineering, University of Aberdeen, Scotland, UK.

http://www.erg.abdn.ac.uk/users/gorry Date: 10/11/1995 Revised: 7/10/2003