3. (20 points) Web Caching Consider the following network, where hosts in an ins

Question

3. (20 points) Web Caching Consider the following network, where hosts in an institutional network can download files from both remote origin servers and a local proxy cache. origin servers 2 Mbps access linlk 10 Mbps AN Iweb che Suppose: The average object size is 100,000 bits. The average request rate from the institution's browsers to the origin servers is 10 requests/sec The missing rate of the web cache is 0.3. The round-trip delay from the access router to any origin server and back to router is 2 sec. The round-trip delay from the clients to the local proxy cache is 2 msec. - Ignoring the time for DNS query. For the average Internet access delay, use /(1-M an object over the access link and is the arrival rate of objects to the access link. Find the average total response time for a client to download a file. ) , where is the average time required to se

Explanation / Answer

Average Total response time = average access delay + average internet delay

Average access delay = / (1 – )

= average time required to send one object over the access link = transmission time of one object = average object size / transmission data rate of access link = 100,000 / (2 * 106) = 0.05 sec

= arrival rate of objects to access link = 10 requests per second

= traffic intensity of access link = ratio of the time during which access link is occupied to the time that the link is available for occupancy = (0.05) (10) = 0.5

Average access delay = (0.05) / (1 - 0.5) = 0.1 sec

Average internet delay = 2 sec

Therefore, total average response time = 0.1 + 3 = 3.1 sec

THANK YOU. DO UPVOTE, IF YOU FIND THIS USEFUL

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.