Which network function is associated with error detection and flow control in the Transport layer?

• A. MAC address resolution
• B. Frame encapsulation at the Physical layer
• C. Path selection in the Network layer
• D. Error detection and flow control

Answer: (D)

The Transport layer is responsible for end-to-end reliability, which includes both error detection and flow control. In practice, this means mechanisms that ensure data is received correctly and at a pace the receiver can handle. For example, TCP uses checksums to detect corrupted data, acknowledgments to confirm receipt, retransmission of lost segments, and a sliding window to regulate the sender’s data rate. These features together keep the communication reliable and well-paced across the network.

Other options point to functions in other layers: resolving MAC addresses is a Data Link layer activity, frame encapsulation relates to the Data Link and Physical layers, and path selection is a Network layer (routing) function.