[ CCNA · DOMAIN 3 · ROUTING · PLAIN-ENGLISH ANSWER ]
WHAT IS A FLOATING STATIC ROUTE?_
A backup route that stays hidden until the day you need it. The trick is one number: administrative distance.
[ ▶ SHORT ANSWER ]
A floating static route is a backup static route given a higher administrative distance than the primary route, so it "floats" just below the active route and only installs in the routing table when the primary disappears. A normal static route has an AD of 1, which beats almost everything; a floating static is given a deliberately high AD (for example ip route 0.0.0.0 0.0.0.0 203.0.113.2 200) so a more-trusted route — a directly learned static, or an OSPF/EIGRP route — is preferred while it's available. The moment the primary route's next hop becomes unreachable, the floating route is the next-best option and takes over. It's the standard way to build simple failover, like a backup WAN link, without running a routing protocol over it.
Routers decide between competing routes to the same destination using administrative distance (AD) — a trust score where lower wins. A floating static route is just a static route that exploits that rule on purpose: give it a high AD and it sits in reserve, ready to take over.
How it works
Normally a static route has an AD of 1, so it beats nearly any protocol-learned route. A floating static is given an AD higher than the route you want to use first. While the primary route is valid, it wins and the floating route is held back. When the primary's next hop goes unreachable and the route is withdrawn, the floating static becomes the best remaining option and is installed.
Configuring one
Classic dual-ISP example — a primary default route out the main link and a floating backup out a second ISP:
! Primary default route (default AD 1)
R1(config)# ip route 0.0.0.0 0.0.0.0 203.0.113.1
! Floating backup default route (AD 200 - stays inactive)
R1(config)# ip route 0.0.0.0 0.0.0.0 198.51.100.1 200
Run show ip route and only the primary appears. Drop the primary link and the AD-200 route immediately shows up in its place.
Choosing the AD value
The only rule: the floating route's AD must be higher than the route it's backing up (and below 255, which means "never install"). Backing up another static (AD 1)? Use 2+. Backing up OSPF (AD 110)? Use something above 110, like 130 or 200. The specific number is a style choice; the ordering is what matters.
Why use one
For a single backup path, a floating static is the simplest failover there is — no routing protocol to configure or troubleshoot across the backup link, just one extra line that quietly waits for trouble.
★ RELATED QUESTIONS
[ What administrative distance should a floating static route use? ]
Any value higher than the primary route's AD and below 255. If the primary is another static (AD 1), use 2 or more; if the primary is OSPF (AD 110), use something above 110 like 130 or 200. The exact number doesn't matter as long as it's higher than the primary.
[ How is a floating static route different from a normal static route? ]
Only the administrative distance. A normal static route uses AD 1 and is almost always active. A floating static has a raised AD, so it stays out of the routing table until the more-trusted primary route fails.
[ Why use a floating static route instead of a routing protocol? ]
Simplicity. For a single backup link you don't need the overhead of running OSPF or EIGRP across it — a floating static gives clean automatic failover with one line of config.
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