Here is another question – guess which domain if you can:
The encoding and decoding of bits through transmitting and receiving devices best describes what?
a) The Physical Layer
b) Network Layer devices
c) Presentation layer processes
d) The Transport Layer
This question comes from Domain 4, Communication and Network Security. This domain comprises of 14% of your total score on the CISSP exam not including the beta questions. If you’re familiar with the Open Systems Interconnect (OSI) model, you’ll quickly realize that this is talking about the physical layer, which “pushes” bits through devices. What might make this question a bit confusing is that you won’t be given a domain category during the exam – once you begin, the questions are presented without context and you need to know and understand the material. Another confusing element might be the words “encoding” and “transmitting”. Don’t overthink things. Whenever they are talking about encoding/decoding bits, it is referring to Layer 1, the physical layer. The key words are bits, transmitting, and devices.
Overthinking the question might lead you to use your own knowledge and expertise – don’t do this! Remember that they are testing your knowledge of the CBK, not anything else. Encoding of data occurs at the upper layers, so you could be tempted to select option C, but the correct answer is A, the physical layer.