  Age-of-information (AoI) is a metric quantifying information freshness at the
receiver. It captures the delay together with packet loss and packet generation
rate. However, the existing literature focuses on average or peak AoI and
neglects the complete distribution. In this work, we consider a N-hop network
with time-invariant packet loss probabilities on each link. We derive closed
form equations for the probability mass function of AoI. We verify our findings
with simulations. Our results show that the performance indicators considered
in the literature such as average or peak AoI may give misleading insights into
the real AoI performance.
