Which layer is responsible for addressing and routing data packets?

The Network layer is responsible for addressing and routing data packets across different networks. It serves as an intermediary between the Transport layer, which is responsible for process-to-process communication, and the Data Link layer, which handles node-to-node communication. The primary function of the Network layer is to determine the best path for the data packets to travel from the source to the destination across multiple networks.

This layer utilizes logical addressing, such as IP addresses, to uniquely identify devices on the network and facilitate routing. It involves protocols like IP (Internet Protocol), which breaks down the data into packets and manages the pathways these packets take to ensure they reach the correct destination efficiently. Routing algorithms and tables at this layer further assist in determining how to forward these packets based on their destination addresses.

In contrast, the roles of the Application layer, Transport layer, and Data Link layer are distinct and focus on different aspects of network communication, such as providing services to end-user applications, ensuring reliable data transport, and handling physical addressing and error detection on individual links, respectively.