Which OSI layer is responsible for routing decisions and logical addressing?

• A. Layer 1
• B. Layer 2
• C. Layer 3
• D. Layer 4

Answer: (C)

Routing decisions and logical addressing are handled at the Network layer. This layer determines the path a packet takes between different networks and uses logical addresses, such as IP addresses, to identify the destination across those networks. Routers operate here, consulting routing tables and protocols (like RIP, OSPF, or BGP) to pick the next hop toward the destination. This contrasts with the Physical layer, which deals with the actual transmission medium and signaling; the Data Link layer, which handles MAC addressing and local switching within a single network; and the Transport layer, which manages end-to-end communication, reliability, and port numbers. Because routing across networks and logical addressing are the core responsibilities of the Network layer, it’s the layer that governs these decisions.