Question

I just need a walk through for d and e for problem 8 please. Thanks!

8. Referring to problem P7, suppose the HTML file refernces eight very small objects on the same server. Neglecting transmission times, how much time elapses with
a. Non-persistent HTTP with no parallel TCP connections?
b. Non-persistent HTTP with the browser configured for 5 parallel connects?
c. Persistent HTTP?

In 8C, please consider both persistent HTTP with and without pipelining; D. redo a. and c. assuming an object transmission delay of Do and a direct link between server and client; E. redo a. and c. assuming an object transmission delay of Do and m links between server and client, whereby each link has a round-trip delay of RTT0 and employs store + forward transmission for each object

Question P7 for reference only:
Suppose within your Web browser you click on a link to obtain a Web page. The IP address for the associated URL is not cached in your local host, so a DNS lookup is necessary to obtain the IP address. Supposed the n DNS servers are visited before you host receives the IP address from DNS; the successive visits incur an RTT of RTT1, ..., RTTn. Further suppose that the Web page associated with the link contains exactly one object, consisting of a small amount of HTML text. Let RTT0 denote the RTT between the local host and the server containing the object. Assuming zero transmission time of the object, how much time elapses from when the client clicks on the link until the client receives the object?

Answer 1

8 a. First query the DNS setup, once you have to setup the connection and then request 8 files:

RTT₁ + RTT₂ + RTT₃ + ... + RTT_n + 8 * 2 RTT₀ = 18 RTT₀ + RTT₁ + ... + RTT_n

8 b. First query the DNS setup, once you have to setup the connection. Then request 5 concurrently and then request rest 3 files:

RTT₁ + RTT₂ + RTT₃ + ... + RTT_n + 2 RTT₀ + 2* 2 RTT₀ = 6 RTT₀ + RTT₁ + ... + RTT_n

8 c. First query the DNS setup, once you have to setup the connection and here receive all the 8 files without any extra request:

RTT₁ + RTT₂ + RTT₃ + ... + RTT_n + 2 RTT₀ + RTT₀ = 3 RTT₀ + RTT₁ + ... + RTT_n