Which operation does a router perform to decide where to forward a packet?

• A. Look up the routing table
• B. Check the CAM table
• C. Consult the ARP cache
• D. Inspect the TTL value

Answer: (A)

Routing hinges on looking up the destination IP in the router’s routing table. The table lists network prefixes and the next-hop or exit interface for each path. The router uses the longest prefix match to pick the most specific route, then forwards the packet out the chosen interface toward that next hop. If no specific route exists, it may fall back to a default route.

The other items don’t drive the decision. The CAM table is used by switches to map MAC addresses to ports, not to choose routes. The ARP cache resolves an IP to a MAC on the local network after a route is chosen. The TTL value is a health check for packet lifetime and doesn’t determine routing.