Which ISO/OSI layer establishes the communications link between individual devices over a physical link or
channel?

A.
Transport layer

B.
Network layer

C.
Data link layer

D.
Physical layer

Explanation:
The data link layer is responsible for proper communication within the network devices and for changing the
data into the necessary format (electrical voltage) for the physical link or channel.
Incorrect Answers:
A: The protocols at the transport layer handle end-to-end transmission and segmentation of a data stream.
B: The responsibilities of the network layer protocols include internetworking service, addressing, and routing.
D: The physical layer include network interface cards and drivers that convert bits into electrical signals and
control the physical aspects of data transmission

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 531