IP SLA tracking syntax
When implementing an IP SLA, and applying the object tracking instance with the IP SLA instance, we can use the following command:
R1(config)#track 5 rtr 1
The first number (track 5) refers to the track number used to track a particular object, such as a static route. The second number (rtr 1) refers to the IP SLA instance that has been configured.
This is the syntax that is used for IOS versions before 12.2(33). The newer revised syntax is as follows:
R1(config)#track 5 ip sla 1 reachability
track 5 refers to the track number as before, and
ip sla 1 refers to the IP SLA instance. The reachability keyword indicates that the statement tracks whether the specific object is reachable.