Which of the following layer of OSI Reference model is also called end-to-end…

Answer: Transport layer.

Explanation: The transport layer is called the end-to-end layer because it provides services that enable direct communication between processes on different hosts.

• Segmentation and reassembly: Breaks application data into segments at the sender and reassembles them at the receiver.

• Reliability: Provides reliable delivery when using protocols like TCP (error detection, retransmission, acknowledgements).

• Flow control and congestion control: Prevents sender from overwhelming the receiver or the network.

• Multiplexing and demultiplexing: Uses port numbers to deliver data to the correct application processes.

Why the other layers are not considered the end-to-end layer:

• Network layer: Handles routing and logical addressing (IP) between networks, but does not provide transport-level reliability or port-based multiplexing.

• Data link layer: Manages node-to-node framing and error detection on a single link; its scope is the local network segment, not end-to-end host communication.

• Session layer: Coordinates and manages sessions between applications but does not implement segmentation, end-to-end reliability, or port multiplexing provided by the transport layer.