multiplexing...

i have always combined the ideas of encapsulation/deencapsulation with multiplexing... in fact i thought they were the same... no... see also tdm,sdm and cdm

from: http://www.mindregal.com/netfund.php?id=Encapsulation

Encapsulation is the process of adding header information by each layer to the original data as data goes down in the OSI layer. 

Once entire encapsulated information is reached at other end, de-encapsulation occurs and retrieve the original data from the encapsulated information.

De-encapsulation is the process of stripping off the header of the PDU information at each layer as the information is passed up from layer to layer of the OSI Reference Model.

that's a good explanation...

on to multiplexing...


here is a  link for those with the stomach to dig deeper...

http://books.google.com/books?id=On_Hh23IXDUC&pg=PA264&lpg=PA264&dq=osi+layers+and+multiplexing&source=bl&ots=pRafejp6zV&sig=gN6ZE0YAR5vNHhIpxkszFAIxtfk&hl=en&sa=X&ei=V9ESUfD4HurW0QGxg4CIAw&ved=0CFQQ6AEwBTgK#v=onepage&q=osi%20layers%20and%20multiplexing&f=false

more here...

http://en.wikipedia.org/wiki/OSI_model

and here...

http://www.tcpipguide.com/free/t_OSIReferenceModelLayerSummary.htm

have fun...