Answer:
The Tp value 0.03 micro seconds as calculated in the explanation below is negligible. This would lead to a similar value of time delay for both persistent HTTP and non-persistent HTTP.
Thus, persistent HTTP is not faster than non-persistent HTTP with parallel downloads.
Explanation:
Given details are below:
Length of the link = 10 meters
Bandwidth = 150 bits/sec
Size of a data packet = 100,000 bits
Size of a control packet = 200 bits
Size of the downloaded object = 100Kbits
No. of referenced objects = 10
Ler Tp to be the propagation delay between the client and the server, dp be the propagation delay and dt be the transmission delay.
The formula below is used to calculate the total time delay for sending and receiving packets :
d = dp (propagation delay) + dt (transmission delay)
For Parallel downloads through parallel instances of non-persistent HTTP :
Bandwidth = 150 bits/sec
No. of referenced objects = 10
For each parallel download, the bandwith = 150/10
= 15 bits/sec
10 independent connections are established, during parallel downloads, and the objects are downloaded simultaneously on these networks. First, a request for the object was sent by a client . Then, the request was processed by the server and once the connection is set, the server sends the object in response.
Therefore, for parallel downloads, the total time required is calculated as:
(200/150 + Tp + 200/150 + Tp + 200/150 + Tp + 100,000/150 + Tp) + (200/15 + Tp + 200/15 + Tp + 200/150 + Tp + 100,000/15 + Tp)
= ((200+200+200+100,00)/150 + 4Tp) + ((200+200+200+100,00)/15 + 4Tp)
= ((100,600)/150 + 4Tp) + ((100,600)/15 + 4Tp)
= (670 + 4Tp) + (6706 + 4Tp)
= 7377 + 8 Tp seconds
Thus, parallel instances of non-persistent HTTP makes sense in this case.
Let the speed of propogation of the medium be 300*106 m/sec.
Then, Tp = 10/(300*106)
= 0.03 micro seconds
The Tp value 0.03 micro seconds as calculated above is negligible. This would lead to a similar value of time delay for both persistent HTTP and non-persistent HTTP. Thus, persistent HTTP is not faster than non-persistent HTTP with parallel downloads.
