Need help with those three questions.

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Suppose that you are browsing a web page with a very small index file and 10 JPEG files each at 8 M Bytes. The bandwidth at the server is 1 Gbps. The round trip time (RTT) between your computer and the web server is 30 ms. Please compute the total time needed to obtain the complete web page with

non-persistent HTTP

non-persistent HTTP with 6 parallel connections

persistent HTTP.

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Consider distributing a file of F = 15 Gbits to N peers. The server has an upload rate of us = 30 Mbps, and each peer has a download rate of di = 2 Mbps and an upload rate of u. For N = 10, 100, and 1,000 and u = 300 Kbps, 700 Kbps, and 2 Mbps, prepare a chart giving the minimum distribution time for each of the combinations of N and u for both client-server distribution and P2P distribution.

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Suppose that there is a high school that has an Internet access link with the speed being 2 Mbps (in both uplink and downlink). The average request rate from browsers at all computers in this high school to origin remote servers is 16/sec, and the average object size is 120K bits. RTT from the high school router to any origin server is 2 sec.

a. Please compute the utilization of the access link (downlink)

b. Please recompute the utilization of the access link (downlink) if the high school upgrade it to 20 Mbps

c. Suppose that a local cache is installed and the link speed stays at 2Mbps, and the cache hit rate is 0.6. Please re-compute the access link utilization

d. Compute the average total access delay when the local cache is installed. Assume that the transmission time for each object and the access time to the local cache is negligible compared with RTT time.

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