Problem 4 Consider hosts in an institutional network accessing content via the following network. Suppose each object is 80K bits, hosts in the institutional network generate 18 requests/sec, and hosts from other parts of the Internet (not shown) generate 100 requests/sec. Suppose that the total delay for Router2 to send a request to Router3 and Router3 to send the response back to Router2 is 2 seconds. Ignore propagation delays for other links. lgnore delays for Conditional GET messages and their responses Approximate the access link delay (including queuing and transmission delays) by 1/(u 1), where u is the service rate and A is the arrival rate (unit: objects/sec) Router4 Router3 R. 20 Mbps origin serverS Internet RTT 2 sec ontent provider Router 1 Gbps LAN R 1.54 Mbps outer1 1 Gbps LAN cache institutiona network a) b) c) Find the total delay for obtaining one object from the origin server to a host in the institutional network. Suppose that 20% of requests generated by the institutional network are served by a local cache (i.e., the cache hit rate is 0.2). Repeat a) What is the minimum cache hit rate to make the delay no greater than 100 ms