Explain what the OSI reference model is and why it is useful.

Correct Answer:

The OSI reference model is a seven-layer framework that shows how data moves across a network. The layers are physical, data link, network, transport, session, presentation, and application. Each layer has a specific job and supports the layer above it. The model is useful because it gives people a common language for describing networks, helps designers build compatible systems, and makes troubleshooting easier by letting you identify which layer a problem is happening in.