Exam-style question
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Describe the role of each of the four layers of the TCP/IP stack. Then explain how data intended for a particular application on another device can be directed to the correct device and process.
Model answer
What a good answer should say
- The application layer provides network services to applications.
- The transport layer provides communication between processes and uses port numbers to identify the relevant application or service.
- The network layer is responsible for addressing and routing data between networks so that it can reach the destination device.
- The link layer transfers data across the local network and uses MAC addresses to identify devices on that local network.
Explanation
Why this works
A complete answer distinguishes the four layers rather than treating TCP/IP as a single operation. It also distinguishes an IP address, which supports delivery between networks, a MAC address, which supports local-network delivery, and a port number, which identifies a process.
Mentioning a socket shows how an IP address and port form a communication endpoint.
Common mistake
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