Which layer manages traffic flow control in end-to-end communication?

The layer responsible for managing traffic flow control in end-to-end communication is the Transport layer, which is Layer 4 of the OSI model. This layer ensures that data is transmitted reliably and efficiently between hosts over a network. It implements mechanisms for flow control, allowing devices to control the rate of data transmission based on the current network conditions and the receiver's processing ability.

By managing the pace at which data packets are sent and confirming receipt through acknowledgments, the Transport layer helps to prevent packet loss and ensures that all data arrives in the correct sequence. Protocols such as TCP (Transmission Control Protocol) at this layer are specifically designed for reliable transport, expanding on the control of data flow to enhance overall communication efficiency.

The other layers do play important roles in data transmission but do not focus on flow control in the same way. The Physical layer deals with the actual transmission of raw bitstreams over a physical medium, the Data Link layer is tasked with node-to-node data transfer and error detection/correction within a local network segment, while the Network layer is responsible for path determination and logical addressing across multiple networks. None of these layers manage end-to-end traffic flow control as thoroughly as the Transport layer does.