3. (35 marks) Consider Figure 2 for which there is an institutional network connected to the Internet. Suppose that the average object size is 80,000 bits and that the average request rate from the institution's browsers to the origin servers is 18 requests per second. Also suppose that the amount of time it takes from when the router on the Internet side of the access link forwards an HTTP request until it receives the response is 1.5 seconds on average. Let the average time be the sum of the average access delay and the average Internet delay. For average access delay, use A/(1 AB), where A is the average time required to send an object over the access link and B is the arrival rate of objects to the access link. origin servers public Internet 1.6 Mbps access link institutional network 10 Mbps LAN Figure 2: Diagram for Problem 3 (a) (20 marks) Find the average response time. (b) (15 marks) Now suppose a cache is installed in the institutional LAN. Suppose the miss rate is 0.4. Find the response time. Note that the response time is close to zero if the request is satisfied by the cache