1. Which layer of the OSI model includes IP addresses?

Answer: B

Explanation:

The Network layer of the OSI model includes IP addresses.

IP addresses are utilized at the Network layer of the OSI model, which is responsible for routing packets of data across different networks.

A) Application

The Application layer is the topmost layer of the OSI model and is responsible for providing network services directly to end-user applications. It does not handle IP addresses; instead, it deals with high-level protocols like HTTP, FTP, and SMTP.

B) Network

The Network layer is where IP addresses are defined and utilized for routing data packets between devices across different networks. This layer manages the addressing and routing of packets, making it essential for data transmission over the internet.

C) Session

The Session layer is responsible for establishing, managing, and terminating sessions between applications. It does not involve IP addressing or routing; rather, it focuses on maintaining communication sessions and ensuring that data is properly synchronized.

D) Transport

The Transport layer is responsible for ensuring reliable data transfer between devices. It deals with data segmentation and flow control, but it does not utilize IP addresses, which are specific to the Network layer for routing purposes.

Conclusion

The Network layer is definitively the correct answer as it is specifically responsible for the use of IP addresses in routing data. In contrast, the Application, Session, and Transport layers serve different functions and do not involve IP addressing, thus reinforcing the importance of the Network layer in the OSI model.