At which OSI layer is data added to a PDU during the encapsulation process?network layertransport layerdata link layerapplication layerNavigation Bar

The encapsulation process in the OSI model involves adding headers and trailers to data at each layer. Here's a step-by-step breakdown:

1. Application Layer: This is where the data generation and reception occur. The data is prepared for transmission over the network.

2. Presentation Layer: This layer is responsible for data translation and code formatting.

3. Session Layer: This layer establishes, manages, and terminates connections between applications.

4. Transport Layer: This layer segments and reassembles data into a data stream. It adds a header to the data from the session layer. This header includes information such as the source and destination port numbers.

5. Network Layer: This layer adds another header, creating a packet. This header includes logical addressing and routing information.

6. Data Link Layer: This layer adds a header and trailer to create a frame. The header includes physical addressing information.

7. Physical Layer: This layer converts the frame into a digital signal for transmission over the network medium.

So, to answer your question, data is added to a Protocol Data Unit (PDU) at each layer during the encapsulation process. However, if you're asking at which layer the data first becomes a PDU, that would be at the Transport Layer, where it becomes a segment.