Question

Difficulty: MediumIPv4 Static Routing

A network administrator needs to configure and verify a floating static route on a Cisco IOS router to back up a primary OSPF path (Administrative Distance 110) for destination network 10.50.0.0/2410.50.0.0/24 via next-hop IP 192.168.12.2192.168.12.2. Place the required configuration and verification steps in the correct chronological order.

  1. 1Enter global configuration mode by executing privileged EXEC mode command `configure terminal`.
  2. 2Configure the floating static route using `ip route 10.50.0.0 255.255.255.0 192.168.12.2 120`.
  3. 3Confirm that the primary OSPF route remains installed in the Routing Information Base (RIB) using `show ip route` while the primary link is operational.
  4. 4Shutdown the primary interface or bring down the primary OSPF neighbor adjacency to simulate a primary link failure.
  5. 5Verify that the floating static route with administrative distance 120 is installed into the active routing table using `show ip route 10.50.0.0`.

Answer

The correct operational sequence begins with entering global configuration mode, configuring the static route with an administrative distance of 120 (higher than OSPF's 110), verifying that OSPF remains the active route in the routing table, simulating a primary path link failure, and finally confirming that the floating static route is inserted into the routing table.
The sequence follows standard configuration and verification workflow: enter global config mode -> apply the floating static route command with AD 120 -> verify primary path retention in RIB -> force failover by shutting down primary path -> verify backup static route installation in RIB.

Step-by-Step Solution

1
Access CLI configuration mode
Router transitions to global configuration prompt
CLI commands altering routing topology must be executed in global configuration mode.
2
Configure the IPv4 floating static route
Route `ip route 10.50.0.0 255.255.255.0 192.168.12.2 120` is added to router candidate table
An Administrative Distance of 120 ensures the static route is floating because it is higher than OSPF's AD of 110.
3
Verify initial RIB state
OSPF route is present in routing table; floating static route is absent
The router selects routes with lower Administrative Distance when multiple paths exist.
4
Simulate primary interface failure
OSPF path is removed from RIB due to dead neighbor / link down
The primary route withdrawal triggers route selection re-evaluation for destination network 10.50.0.0/2410.50.0.0/24.
5
Verify failover to backup floating static route
Static route via 192.168.12.2192.168.12.2 with AD 120 is installed in RIB
With the lower AD route gone, the floating static route becomes the best available path.

Key Concept

Floating Static Route Configuration and Failover Lifecycle
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