Your question is Explain Router ARP Resolution. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You are debugging why a host can send traffic to a remote subnet but the first packet is delayed and some flows fail intermittently after a next-hop change. The path includes a router that must forward the packet onto an Ethernet segment where it may not yet know the destination MAC address. You need to explain what the router does from the moment it receives the packet until it can transmit the frame on the outgoing interface.
Walk me through the step-by-step process of how ARP works when a router receives a packet that it needs to forward on an Ethernet network. Explain what the router checks first, when it sends an ARP request, how it uses the ARP cache, and what happens if ARP resolution fails.