4. = A Poisson stream of packets arrives to a single-channel communication link at a rate of 2 200 packets/s and are allowed to join a large buffer size with FIFO queue discipline with transmission rate of 64 kbits/s. The arrivals consist of a random mixture of the following packet sizes: Packet size (bits) Probability of arrival 160 25% 80 25% 320 50% Determine the average waiting time in the queue and the average number of packets in the system.