What layer is responsible for transporting data segments and ensuring error control?

The transport layer is primarily responsible for the reliable transmission of data segments between two endpoints in a communication network. It ensures that data is transferred correctly and in sequence, providing functionalities such as error detection and correction. This layer manages flow control, which helps in preventing data overload and ensures that the sender does not overwhelm the receiver.

Additionally, the transport layer can provide segmentation of data, dividing larger messages into smaller packets to make efficient use of the network. It uses protocols such as TCP (Transmission Control Protocol), which includes mechanisms for ensuring that segments are received correctly. In contrast, while the physical layer focuses on the physical transmission of data, and the network layer is responsible for addressing and routing, the transport layer specifically manages the flow of data and ensures its integrity during transport. This uniquely establishes it as the layer dedicated to error control and data segment management.