Which OSI layer handles the transmission of data between hosts in different networks and routing?

• A. Network Layer
• B. Data Link Layer
• C. Physical Layer
• D. Application Layer

Answer: (A)

Inter-network data transmission and routing are responsibilities of the network layer. This layer moves packets from a host on one network to a host on another network, using logical addressing (such as IP addresses) to identify devices across multiple networks and routing decisions to determine the best path for the packets. It handles forwarding between routers, path selection, and can perform fragmentation if needed along the way. The data link layer, in contrast, manages communication between devices on the same physical network segment with hardware addresses (MACs) and framing. The physical layer deals with the actual electrical or optical signaling that carries bits, while the application layer hosts end-user protocols and services.