What is multiplexing in OSI model

[Halyn]

I want to know what do you mean by multiplexing with reference to OSI model? I have heard this term many a times in my college and also at many places but don't know what does it mean. Is there anyone who can explain me what is multiplexing based on OSI model?

[Kirt]

According to wikipedia, multiplexing (also known as muxing) is a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium. The aim is to share an expensive resource. The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, can extract the original channels on the receiver side. A device that performs the multiplexing is called a multiplexer (MUX), and a device that performs the reverse process is called a demultiplexer (DEMUX).

[Snake08]

Multiplexing means adding signals together for transmission and breaking them apart upon reception. It is the process where multiple channels are combined for transmission over a common transmission path. This activity indeed occurs at the Physical Layer in the OSI model while multiple access also involves a media access control protocol.

[Spyrus]

Multiplexing is the process of combining two or more signals into one signal. A two input multiplexing device will require three inputs; one for each of the signals and one for the control signal. A multiplexing technique may be further extended into a multiple access method or channel access method.