Static floating route is static route like any other but with added administrative distance in the configuration
R1(config)#ip route 172.16.10.0 255.255.255.0 10.10.10.2 200
Defining the packets route using Static Floating Routes is very interesting topic so I decided to give you a short description of Static floating routes with an example. Static floating route is the same as normal static route except that this kind of static route has Administrative distance configured to some other value than 1.
Remember that if we configure normal static route like this:
R1(config)#ip route 172.16.10.0 255.255.255.0 10.10.10.2
It will send all packets destined for 172.16.10.0/24 network to the neighbor with interface address 10.10.10.2 and of course that static route will have Administrative distance (AD) of 1 by default. If we make the configuration like this:
R1(config)#ip route 172.16.10.0 255.255.255.0 Serial 0/0
In this case the AD will be zero (0). Pretty cool right? I didn’t know that difference for a long time but there is another article in the process of writing that explains why that is so.
In either cases of course, this would be normal because almost every time we configure the static route to override some routing protocol decision. But what if we want to use a static route to make something completely opposite? If we want to use static route only to be a backup route to some subnet then we will need to give the precedence to the path learned by some IGP (Interior Gateway Protocol) like OSPF for example. We know that most paths (routes) learned by OSPF protocol have Administrative Distance of 110. In that case the Administrative distance of some static route needs to be bigger than 110 if we don’t want to kick out the OSPF route from routing table.