Question

1. Peristent vesus non-persistent TCP Connections/web page retrieval: This problem is a continuation of the problem in homework 4. Assume the Web server’s IP address is stored in your local DNS server’s cache and RTT0 = 5msec. The RTT for communication between the client and the Web server (RTTHTTP) is 100 msec. Transmission time = 0 for every packet.

a. Calculate the total time to load the web page and 2 objects using the TCP Connections indicated assuming a persistent TCP connection WITH pipelining.

Answer 1

A Persistent TCP connection does not require setup connection again and again for every object.
A non-persistent TCP connection requires to setup connection for every object.

Since question is about persistent TCP connection, connection is not required again and again,

pipelining means we are sending multiple requests in a single TCP connection without wating for there responces.

The calculation will involve below steps:

Step1: First, We need to find address of the page, ( in our case it is inour local DNS), RTT0 = 5msec.

Step2: Now we need 1 RTTHTTP to open TCP connect, 1 RTTHTTP to load webpage and 2 objects, and 1 RTTHTTP to close connection. i.e 3RTTHTTP = 300msec

so total time = 5msec + 300msec = 305msec