ARP Cache Clear

Why ARP caches use timeout mechanisms

This is a straightforward networking question that tests understanding of the Address Resolution Protocol and the practical constraints of maintaining dynamic mappings between IP and MAC addresses. It appears regularly in systems and infrastructure interviews where candidates need to reason about protocol design trade-offs.

The question asks you to think beyond the basic function of ARP—translating IP addresses to hardware addresses—and consider the real-world challenges of keeping cached information accurate. A strong answer identifies the specific failure modes that timeouts prevent, the time scales involved, and why a simple request-response model is insufficient for long-lived network connections.

• Address resolution and MAC-to-IP bindings
• Network topology changes and host mobility
• Cache coherence and stale data
• Trade-offs between performance and correctness