Anantharam, VenkatTsoucas, P.Concavity of the output process with respect to buffer size is established in a series of DOT/M/1/B queues with loss at the first node. Similarly, one shows concavity of the throughput with respect to the number of servers and the buffer sizes in a node belonging to a series of DOT/M/s/B queues.en-USTechnical Report