Ethernet Type of ARP

Understanding Ethernet type values for ARP frames

This is a straightforward easy-difficulty networking question that tests foundational knowledge of the Ethernet frame structure and the Address Resolution Protocol (ARP). It's the kind of question that appears in systems interviews at infrastructure-heavy firms and in technical screening for roles that involve packet-level networking.

To answer this question, you need to understand how Ethernet frames use a type field to identify which protocol operates at the network layer. ARP is assigned a specific standardized hexadecimal value in this field, which every network interface must recognize in order to process ARP packets correctly. Knowing this value — and why it exists — demonstrates familiarity with the OSI model and how different protocol layers communicate.

• Ethernet frame format and the type/length field
• Protocol identification in network packets
• The role of ARP in IP networks