At which layer is a logical address added during the encapsulation process?

The logical address is added during the encapsulation process at the network layer. This layer is responsible for routing packets of data between devices across different networks. Logical addressing involves the assignment of IP addresses, which are essential for identifying devices across a network and permitting them to communicate with each other.

When data is prepared for transmission, it passes through the different layers of the OSI model, with each layer adding its own header to the data. At the network layer, the packet is assigned a logical address in the form of an IP address. This address is crucial for determining the best path for the data to travel from its source to its destination, regardless of the underlying physical network.

For context, the transport layer primarily handles end-to-end communication and flow control but does not add logical addresses; instead, it focuses on segmenting the data and ensuring reliable communication. The data link layer, on the other hand, adds hardware or physical addresses (MAC addresses) to frames for communication within the same local network segment. Lastly, the session layer is responsible for managing sessions between applications and does not deal with addressing at any level of the encapsulation process.