Which OSI layer is responsible for IP routing?

• A. Data Link
• B. Application
• C. Transport
• D. Network

Answer: (D)

IP routing is a Network layer function. This layer handles logical addressing with IP addresses and uses routing tables to decide how to forward packets between different networks. Routers operate at this layer, inspecting the destination IP in each packet and sending it toward the next hop that brings it closer to the destination. The Data Link layer deals with delivering frames within a single network using MAC addresses, while the Transport layer focuses on end-to-end delivery and reliability, and the Application layer supports software services. So, routing between networks relies on the Network layer.