There is a single class of tasks with Poisson arrival rate λ at a processing node which takes a fixed-length time interval of D seconds to process a task. These tasks could be aggregated in a way that from the first arrival, within D, the requests in this interval are aggregated to the first arrival. In other words, the requests in this interval are removed except the first one(within D seconds after it). What I want to know is the departure rate from the processing node.
My thought:
$\lambda$ if $D*\lambda\leq 1$
$1$ if $D*\lambda\gt 1$