What is the primary function of the network layer in the OSI model?

The primary function of the network layer in the OSI model is to manage packet forwarding, including routing through intermediate routers, which determines the best physical pathway for data transmission. This layer is responsible for logical addressing, which identifies devices on a network and allows packets to be directed from source to destination.

In this context, the network layer focuses on how data is sent to the correct destination across multiple hops and networks, ensuring that each packet follows an efficient route to reach its endpoint, regardless of the underlying hardware. This routing function is crucial for data communication, particularly in larger and more complex networks, where multiple paths may exist.

While ensuring error-free delivery involves aspects of error detection and correction, this functionality is the responsibility of the data link layer and the transport layer, not the network layer. Similarly, enabling application communication belongs to the application layer, which deals with high-level protocols for end-user applications. Interconnecting different local area networks (LANs) is a function tied more closely to the architecture and operation of network devices, such as bridges and routers, which may facilitate connections between networks but are not the primary focus of the network layer itself.