Abstract:
We consider in this paper a double-server double-class retrial queues. Servers, when free, help
serve patients awaiting in the buffers of other servers. Patients arrive at both queues according to Poisson
processes. Each station is fed by a renewal input with general independent identically distributed inter-arrival
times and general identically independent distributed service times possibly different in the two stations. All
service times are exponential, with rates depending on the queues. The cost to be minimized involve cost per
unit time that a patient spends in the system. We find a sufficient conditions including all possible parameter
choices such as arrival rates, retrial rates and service rates. We further present conditions for scheduling new
arrivals, under which server assignment to either queue-1 or queue-2 is cost optimal.
