Question 5 (Weighted fair queue and token bucket 15%). Consider the figures below. Traffic flow A (odd number of packets) arrive in token bucket A, with token rate 1 token/second and bucket size 2. Traffic flow 2 (even number of packets) arrive in token bucket 2, with token rate 1 token/second and bucket size 2. At the beginning, both token buckets are full with tokens. The packets immediately arrive at the weighted fair queue (WFQ) after the passing the token bucket. In WFQ, odd packets have a weight of 1, while even packets have a weight of 2. The WFQ can process 1 packet every 0.5 second. We assume that packets and tokens arrive at integer seconds (labeled by and respectively). The arrival time instants of packets are labeled in the figure. In this question, we assume that a token arrives at t can be immediately consumed by a packet arrives at t. (1) Assume that in the token bucket, packets cannot be dropped. They pass the token bucket if there are enough tokens. They wait if there are not enough tokens. Please figure out when the packets leave the WFQ. Hint: the first four packets left the WFQ are 1, 2, 4, and 3 respectively. They leave the WFQ at 0.5, 1, 1.5, and 2s respectively. (2) Assume that in the token bucket, packets can be dropped. They pass the token bucket if there are enough tokens. They are dropped immediately when there are not enough tokens. Please figure out when the packets leave the WFQ. Hint: still, the first four packets left the WFQ are 1, 2, 4, and 3 respectively. They leave the WFQ at 0.5, 1, 1.5, and 2s respectively. Some packets may never leave the WFQ as they are dropped. 5 3 1 0 2 11 9 7 1 8 6 17 15 13 19 14 2 3 4 12 21 10 23 5 1 I 2 3 4 5 I 6 7 8 Time (s) 18 22 16 20 arriving traffic A I 6 7 8 arriving traffic B Time (s) o token bucket A, 1 token per second bucket size, 2 WFQ token bucket B, 1 tokens per second bucket size, 2 0 I 1 2 1243 1 2 4 3 L 3 4 5 6 7 8 Time (s)