Which layer of the OSI model does TCP operate at?

TCP, or Transmission Control Protocol, operates at Layer 4 of the OSI model, known as the Transport layer. This layer is responsible for establishing, maintaining, and terminating connections between devices over a network. It ensures reliable transmission of data through error recovery and flow control mechanisms. TCP provides these features by segmenting data into packets and ensuring that they arrive in order and without errors.

Layer 2, known as the Data Link layer, deals with physical addressing and the connection between devices on the same network. Layer 3, or the Network layer, is responsible for logical addressing and routing of packets across different networks. Layer 7, the Application layer, enables user interface and application-level protocols but does not directly handle transport or data segmentation. Therefore, the role of TCP aligns specifically with Layer 4, focusing on the transport of data between systems.