Which two functions are carried out at the MAC sublayer of the OSI Data Link Layer?

The MAC sublayer of the Data Link Layer plays a crucial role in managing how devices on a network access the physical medium for data transmission. One of its core responsibilities is to implement protocols that govern how devices share the network medium, which includes implementing mechanisms like Carrier Sense Multiple Access with Collision Detection (CSMA/CD). This protocol helps prevent and manage collisions in networks where multiple devices could attempt to send data simultaneously.

Another primary function of the MAC sublayer is to perform error checking. It ensures that data frames transmitted over the network are checked for integrity. This involves adding frame check sequences to data frames so that the receiving device can verify whether the data has been transmitted correctly or if any errors occurred during transmission. If errors are detected, the MAC layer can initiate a request for retransmission of those frames.

While integrating Layer 2 flows pertains to how data is sequenced and transmitted, error checking is a more specific and fundamental function of the MAC sublayer. Thus, options that reference implementation aspects such as integration of flows and CSMA/CD fall under broader network behaviors that the MAC sublayer influences rather than solely defining its essential functions.