When you click a link in a Web browser, a DNS lookup is needed as the IP address isn't cached locally. Three DNS servers are visited with RTT delays of $2,12,$ and $19$ msecs respectively. The Web page has one object with an RTT to the server of $3$ msecs.

$1.$Calculate time elapsed when client clicks link to receiving object, assuming zero transmission time for HTML$.$

Answer $[$Mark $1]$:

$2.$Time elapsed for one base object and $5$ small objects, using non$-$persistent HTTP and non$-$parallel TCP$.$

Answer:

$3.$Time for same objects with up to $5$ parallel TCP connections and non$-$persistent HTTP$.$

Answer:

$4.$ Time for same objects with up to $5$ parallel TCP connections and persistent HTTP$.$

Answer: