Problem 4. In the network below, there are two Poisson packet streams (one from node 1 to node 6, and another from node 2 to node 6) with arrival rates 1000 and 500 packets/sec, respectively. 50% of the 1- 6 stream packets are sent on route 1-2-3-6, and the others on route 1-4-5-6. Similarly, 50% of the 2-6 stream packets are sent on route 2-3-6, and the other 50% are sent on route 2-5-6. The packet lengths are exponentially distributed and the capacity of every link is 1000 packets/sec. Assume an infinite buffer size at every node, and ignore propagation delays. Session! 1 pkt/ 50% Sasting 2 500 pkts/s 50% 2 3 50% 50% 5 4 (a) What is the average delay for an arbitrary packet entering the network? (b) How many packets of each stream are present in the network on average?