What is the primary function of Layer 3 (Network) in the OSI model?

The primary function of Layer 3, which is the Network layer in the OSI model, is to route packets and determine the best pathway for data to travel across a network. This layer is responsible for logical addressing, ensuring that data packets are sent from the source to the destination by making routing decisions based on the network's topology and the current traffic conditions.

At this layer, protocols such as Internet Protocol (IP) operate, which provide the necessary mechanisms for addressing and routing packets. The Network layer encapsulates data from the Transport layer and segments it into packets, which can then be transmitted through various physical media and across different networks. By using various routing algorithms, devices within this layer ensure that packets take the most efficient route to their destination, which can change dynamically based on factors like network congestion or failures.

The options that involve flow control and error checking, encoding and compressing data, or handling physical connections pertain to different layers in the OSI model. Specifically, flow control and error checking are typically handled at the Transport layer, while encoding and compressing occurs at the Presentation layer, and the physical connections fall under the responsibilities of the Physical layer. This clarity reinforces why routing packets and determining optimal pathways is uniquely the role of Layer 3