200-301 Question 328
Single answerA network administrator has configured a static route on a router with the following command: 'ip route 192.168.1.0 255.255.255.0 10.1.1.1 10'. However, the primary route to the same network is learned via OSPF. What will the router do if the OSPF route to 192.168.1.0/24 is lost?
- A
The router will immediately drop all traffic destined for 192.168.1.0/24.
- B
The router will use the floating static route to forward traffic to 192.168.1.0/24.
- C
The router will switch to another OSPF route for 192.168.1.0/24, if available.
- D
The router will generate an ICMP unreachable message for traffic destined for 192.168.1.0/24.
Show answer and explanation
Correct answer: B
Explanation
A floating static route is a static route configured with an administrative distance higher than that of the dynamically learned route, effectively making it a backup route. In this scenario, the static route with an administrative distance of 10 will only be used if the OSPF-learned route (which has a lower administrative distance of 110) becomes unavailable. This ensures redundancy and prevents traffic loss for the specified destination network.
- A. Incorrect.
This is incorrect because the floating static route with an administrative distance of 10 will be used as a backup route when the primary (OSPF) route is lost.
- B. Correct.
This is correct because the floating static route is configured with a higher administrative distance (10) than OSPF (default is 110). When the OSPF route is no longer available, the router will install the floating static route into the routing table and use it to forward traffic.
- C. Incorrect.
This is incorrect because the router will not find another OSPF route unless explicitly configured, and the static route will take precedence as a backup route.
- D. Incorrect.
This is incorrect because the router will not generate an ICMP unreachable message unless no valid routes are available for the destination.