問題文
A frame arrives at a device that must decide where to send it. The device examines the destination IP address, consults a table of prefixes, and rewrites the Layer 2 header before sending the packet out. Which role does the device perform?
選択肢
- It performs the role of a router, forwarding between subnets based on Layer 3 information.
- It performs the role of a hub, and rewriting the header is a physical layer operation that repeats the signal to every attached port without any lookup at all.
- It performs the role of an address resolution helper, so the rewritten Layer 2 header is the answer it hands back to the host that asked.
- It performs the role of a switch, so the table of prefixes it consulted is the address table that a switch keeps for its local segment.