Step 1: Understanding the Question:
The question asks to identify the layer in the seven-layer OSI (Open Systems Interconnection) model that handles logical addressing (like IP addresses) and the process of routing data packets between different networks.
Step 2: Detailed Explanation:
Let's review the primary responsibilities of the relevant OSI layers:
Data Link Layer (Layer 2): Responsible for node-to-node data transfer on the same physical link. It deals with physical addressing (MAC addresses) and is concerned with frames, not packets across networks.
Network Layer (Layer 3): This layer is responsible for packet forwarding, which includes routing through different routers. It manages logical addressing (e.g., IPv4, IPv6 addresses) to identify hosts on the internetwork and determines the best path for data to travel from source to destination. Routers operate at this layer.
Transport Layer (Layer 4): Responsible for end-to-end communication between hosts. It provides services like segmentation, flow control, and error control. Protocols like TCP and UDP operate here. It uses port numbers but relies on the Network Layer for IP addressing and routing.
Session Layer (Layer 5): Manages sessions between applications, handling session establishment, maintenance, and termination.
The tasks of IP addressing and routing are the core functions of the Network Layer.
Step 3: Final Answer:
The layer of the OSI model responsible for IP addressing and routing is the Network Layer.