Consider the figure below for which there is an institutional network connected to the Internet. The institution LAN link rate is 100 Mbps, and the access link rate is 15 Mbps. Suppose that the average object length is 900,000 bits, and that the average request rate from the institutions browsers to the origin servers is 17.5 requests per second. Also assume the internet delay (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 3 seconds on average. In this problem, consider the total average response time (dtotal) as the sum of the average Internet delay and the average access delay (that is, the delay from Internet router to institution router). The average access delay is given by the following equation daccess= x/|1xa|, where x is the average time required to send an object over the access link, and a is the access link arrival. Note: This | | denotes absolute value.

a) Find the total average response time dtotal

b) Now suppose a cache is installed in the institutional LAN. Suppose the miss rate is 0.4, what is the total response time in this scenario? Any performance improvements?