Lab Objective
Configure a floating static route as a backup to an existing OSPF-learned primary path, verify it remains unused while the primary route is active, then simulate a primary path failure and confirm the floating route automatically takes over.
Lab Purpose
A floating static route is a static route deliberately configured with a higher administrative distance than a preferred dynamic route, so it sits inactive in the background and is used only if the better route disappears — a simple, reliable backup mechanism that requires no complex protocol configuration.
Lab Topology
R1 ---- Gi0/0 (primary, OSPF) ---- R2
R1 ---- Serial0/0/1 (backup, floating static) ---- R2
R2's LAN reachable via OSPF through Gi0/0
in normal operation, distance 110Task 1: Confirm the Primary OSPF Route Is Active
Assuming OSPF is already running between R1 and R2 (as configured in earlier labs), confirm R2's LAN is reachable via the OSPF-learned route through Gi0/0.
Task 2: Configure the Floating Static Route
Configure a static route to R2's LAN via the serial backup link, with an administrative distance higher than OSPF's default of 110.
Task 3: Verify the Floating Route Is Inactive
Confirm only the OSPF route appears in the routing table, with the floating static route not currently installed.
Task 4: Simulate a Primary Path Failure
Shut down R1's Gi0/0 interface to simulate the primary link failing.
Task 5: Verify Automatic Failover to the Floating Route
Confirm the floating static route now appears in the routing table and R2's LAN remains reachable via the backup path.
Solution and Verification
R1# show ip route 192.168.60.0
O 192.168.60.0/24 [110/2] via 10.1.1.2, GigabitEthernet0/0
-- Confirms the OSPF-learned route is currently
-- installed with its default distance of 110R1(config)# ip route 192.168.60.0 255.255.255.0 10.2.2.2 150
-- The trailing "150" sets this static route's
-- administrative distance to 150, deliberately
-- worse than OSPF's 110, so it never competes
-- with the OSPF route while OSPF is availableR1# show ip route 192.168.60.0
O 192.168.60.0/24 [110/2] via 10.1.1.2, GigabitEthernet0/0
-- Only the OSPF route is installed -- the
-- floating static route exists in the
-- configuration but is not yet in the
-- routing table, since its higher distance
-- (150) makes it less preferredR1(config)# interface gigabitethernet0/0
R1(config-if)# shutdownR1# show ip route 192.168.60.0
S 192.168.60.0/24 [150/0] via 10.2.2.2
-- With the OSPF route gone (its interface
-- is down), the floating static route is
-- now the best available path and is
-- automatically installed -- no manual
-- intervention was requiredR1# ping 192.168.60.1
!!!!!
Success rate is 100 percent (5/5)
-- Confirms R2's LAN remains reachable
-- through the backup serial linkKey Takeaway
A floating static route works purely through administrative distance comparison, discussed earlier in this series regarding route preference — no special protocol or additional configuration decides when to switch, only the standard rule that a lower administrative distance always wins whenever multiple sources offer a route to the same destination.