Question

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. Suppose that n DNS servers are visited before your 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?Suppose now, the HTML file references eight very small objects on the same server. Neglecting transmission times, how much time elapses with:i. Non-persistent HTTP with no parallel TCP connectionsii. Non-persistent HTTP with the browser configured for 5 parallel connectionsiii. Persistent HTTP

Answer 1

RTT1+ RTT2+..... RTTn

Step-by-step explanation:

The total estimated time to get the IP address is

RTT1+ RTT2+..... RTTn

Once the IP address is known, O RTT elapses to set up the TCP connection and another O RTT elapses to request and receive the small object. The total response time is

2RTT0+RTT1+RTT2+.....RTTn