The textbook "Data Communications and Computer Networks", by Curt M. White, (Pub. Thomson Learning, Mass.) claims,...
on p 144, "Multiplexing is a technique performed at the physical layer of the OSI model..." Frankly, I find this not only difficult to understand, but difficult to believe. I would have thought that it should go into the Transport, or perhaps the Network layer of OSI. I've just done a multiple-choice test; one question asked about the placement of multiplexing in OSI, and I said, Transport. What do you say?
Multiplexing means adding signals together for transmission and breaking them apart upon reception. Because we're talking only about signals (not frames, packets, or other protocol data units) this activity indeed occurs at the Physical Layer in the OSI model. I agree with your textbook (and in fact, wrote more or less the same kind of thing in my own Course Technology textbook for Thomson Learning as well).
Dig Deeper on Networking Certs and Careers
Related Q&A from Ed Tittel
A network engineer job description will vary. Primarily, it depends on whether the job focuses on engineering a new network or on running a network ...continue reading
System administrator responsibilities are, fundamentally, about the care and feeding of systems but cover a broad range of possibilities when looking...continue reading
Get the inside scoop on a network manager's job description, workload and responsibilities which keep an organization's network infrastructure ...continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.