Which layer is responsible for end-to-end communication between IoT devices and wide area networks?

• A. Network layer
• B. Internet layer
• C. Application layer
• D. Sensor layer

Answer: (A)

End-to-end communication across different networks hinges on routing and addressing, which is handled by the network layer. This layer moves packets from one network to another, making decisions about paths and using addresses so data from an IoT device can traverse gateways and routers all the way to the wide area network. The sensor layer focuses on collecting data from physical sensors, the application layer handles software services and user-facing applications, and while the Internet layer (in TCP/IP terminology) deals with routing within the Internet, the OSI-aligned concept places that routing capability in the network layer. So the network layer is the correct choice because it provides the necessary end-to-end delivery across multiple networks.