A network administrator configures a static route on a Cisco router using the command `ip route 192.168.10.0 255.255.255.0 GigabitEthernet0/1`. Which routing table component is implicitly used as the next-hop for this route?
- AThe IP address of the directly connected interface.
- BThe MAC address of the next-hop router on the GigabitEthernet0/1 segment.
- CThe administrative distance of the directly connected interface.
- DThe IP address of the next-hop router on the GigabitEthernet0/1 segment.
Show answer & explanationAnswer & explanation
Correct answer: D. The IP address of the next-hop router on the GigabitEthernet0/1 segment.
When configuring a static route with only an exit interface on a multi-access network (like Ethernet), the router performs an ARP lookup for the destination network's IP address on that interface. It expects a next-hop IP address to be resolvable via ARP on the specified interface. While the command itself doesn't explicitly state the next-hop IP, it implies that the router will need to resolve one on the interface.
Why the other options are wrong
- A. This is incorrect. The router needs the IP of the *next-hop* router, not its own directly connected interface IP, to forward traffic to the destination network.
- B. While MAC addresses are used in Layer 2 forwarding, the routing table component is concerned with Layer 3 next-hop IP addresses.
- C. Administrative distance is a metric used to select the best path among different routing sources, not a next-hop component itself.
Static Route Next-Hop Resolution (Multi-Access)
When a static route on a multi-access network (e.g., Ethernet) specifies only an exit interface, the router must resolve the next-hop IP address via ARP on that interface to forward traffic.
- Applies to multi-access interfaces (e.g., Ethernet, not point-to-point serial).
- Without an explicit next-hop IP, the router assumes the next-hop is directly reachable on the specified interface.
- Requires ARP resolution for the destination network on the exit interface.
Memory trick: Static routes need a path; multi-access needs a neighbor's IP to leap.