When a Heavy Tailed Service Minimizes Age of Information

Age-of-information (AoI) is a newly proposed performance metric of information freshness. It differs from the traditional delay metric, because it is destination centric and measures the time that elapsed since the last received fresh information update was generated at the source. We show that AoI and packet delay differ in a fundamental way in certain systems, i.e. minimizing one can imply maximizing the other.We consider two queueing systems, namely a single server last come first serve queue with preemptive service (LCFSp) and G/G/∞ queue, and show that a heavy tailed service distribution, that results in the worst case packet delay or variance in packet delay, respectively, minimizes AoI. For the specific case of M/G/1 LCFSp and G/G/∞ queue, we also prove that deterministic service, that minimizes packet delay and variance in packet delay, respectively, results in the worst case AoI.