Preemption According to the dictionary, preempt means “to replace with something considered
to be of greater value or priority.” The redundancy scheme of GLBP allows us to preempt
an AVG with a higher-priority backup virtual gateway that has become available. Forwarder
preemption works in a similar way, except that it’s based upon weighting instead of priority
and is enabled by default. One router can take over another router only during an election, and
preemption is the only way to force an election when a device hasn’t gone down.