Heavy tails in multi-server queues

In this paper, the asymptotic behaviour of the distribution tail of the stationary waiting time $W$ in the $GI\mathrm{/}GI\mathrm{/}2$ FCFS queue is studied. Under subexponential-type assumptions on the service time distribution, bounds and sharp asymptotics are given for the probability $\mathbf{P}\{W>x\}$. We also get asymptotics for the distribution tail of a stationary two-dimensional workload vector and of a stationary queue length. These asymptotics depend heavily on the traffic load.