  Age-of-information is a metric that quantifies the freshness of information
obtained by sampling a remote sensor. In signal-agnostic sampling, sensor
updates are triggered at certain times without being conditioned on the actual
sensor signal. Optimal update policies have been researched and it is accepted
that periodic updates achieve smaller age-of-information than random updates.
We contribute a study of a signal-aware policy, where updates are triggered by
a random sensor event. By definition, this implies random updates and as a
consequence inferior age-of-information. Considering a notion of
deviation-of-information as a signal-aware metric, our results show, however,
that event-triggered systems can perform equally well as time-triggered systems
while causing smaller mean network utilization.
