Examkin

Question

Difficulty: MediumIPv4 Static Routing

A network engineer is configuring an IPv4 static route on router R1 to reach destination network 172.20.40.0/24172.20.40.0/24. The path connects through an Ethernet broadcast multi-access interface (GigabitEthernet0/1) to the next-hop router address 10.0.12.210.0.12.2. Which command configures a fully specified static route that prevents recursive lookup overhead while avoiding excessive Address Resolution Protocol (ARP) table expansion on the multi-access segment?

  1. ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1 10.0.12.2Answer
  2. B
    ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1
  3. C
    ip route 172.20.40.0 255.255.255.0 10.0.12.2 GigabitEthernet0/1
  4. D
    ip route 172.20.40.0 0.0.0.255 GigabitEthernet0/1 10.0.12.2

Answer

The command 'ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1 10.0.12.2' correctly configures a fully specified static route.
The correct command uses the syntax 'ip route 172.20.40.0 255.255.255.0 GigabitEthernet0/1 10.0.12.2'. By providing both the local exit interface and the specific next-hop IPv4 address, the router creates a fully specified route. This prevents recursive table lookup overhead (associated with next-hop IP only) and avoids excessive ARP requests for individual destination IPs (associated with exit interface only on multi-access media).

Step-by-Step Solution

1
Identify the static route requirement for a broadcast multi-access network (Ethernet).
On Ethernet links, specifying only an exit interface causes the router to treat all destination IP addresses as directly connected, issuing ARP requests for every destination host.
Ethernet is a multi-access network requiring Layer 2 MAC address resolution.
2
Evaluate the difference between directly attached, next-hop, and fully specified static routes.
A fully specified static route includes both the local exit interface (GigabitEthernet0/1) and the next-hop IP address (10.0.12.2).
This eliminates the need for recursive routing lookups while pinpointing the exact Layer 2 next-hop neighbor.
3
Verify Cisco IOS syntax ordering and subnet mask formatting.
The correct syntax order is 'ip route <prefix> <mask> <exit-interface> <next-hop-ip>'.
Dotted-decimal subnet masks must be used instead of wildcard masks.

Key Concept

Fully Specified IPv4 Static Route Syntax on Multi-access Networks
Estimated Time:1m 15s
Rate this question

Topics

IPv4 Static Routing

More questions from this topic