Age of Information in a Decentralized Network of Parallel Queues with Routing and Packets Losses
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The paper deals with Age of Information in a network of multiple sources and parallel servers/queues with buffering capabilities, preemption in service and losses in served packets. The servers do not communicate between each other and the packets are dispatched through the servers according to a predefined probabilistic routing. By making use of the Stochastic Hybrid System (SHS) method, we provide a derivation of the average Age of Information of a system of two parallel servers (with and without buffer capabilities) and compare the result with that of a single queue. We show known results of packets delay in Queuing Theory do not hold for Age of Information. Unfortunately, the complexity of computing the Age of Information using the SHS method increases highly with the number of queues. We therefore provide an upper bound of the average Age of Information in a parallel server system of an arbitrary number of M/M/1/(N + 1) queues and its tightness in various regimes. This upper bound allows providing a tight approximation of the Age of Information with a very low complexity.
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