1. A concentrator receives messages from a group of terminals and send them over a transmission line. Suppose that messages are arriving according to Poisson process at a rate of 1 message for every 4 ms. The message transmission time is exponentially distributed with mean 3 ms. Delayed messages are stored in a infinite-long queue. Compute the following: (a) Average number of messages in the system. (b) Average total delay in the system. (c) What percentage increase in arrival rate will result in doubling the average delay? (d) If the message delay has to be bounded by 10 ms as per the communication system protocol, how fast the server should work in transmitting the messages (with = 0.25 message/ms)?