HTTP Non-Persistent & Persistent Connection | Set 2 (Practice Question)

Prerequisite: HTTP Non-Persistent & Persistent Connection - Set 1

For question point of view you need to know that Non-persistent connection is known as HTTP 1.0 and Persistent connection is known as HTTP 1.1.

• Non-Persistent Connection: It requires connection setup again and again for each object to send.
• Persistent connection: It does not require connection setup again and again. Multiple objects can use same connection.

Question: Assume that you have base HTML file with 30 embedded images, images & base file are small enough to fit in one TCP segment. How many RTT are required to retrieve base file & images under-following condition :

(i) Non-Persistent connection without parallel connection

(ii) Non-persistent connection with 10 parallel connection

(iii) Persistent connection without pipe-lining

(iv) Persistent connection with pipe-lining

(Assume RTT dominates all other time)

Explanation:

2RTT is the initial required connection one for TCP connection and one for HTML base file.

Total time = 2RTT + transmit time

(i) Non-Persistent connection with no parallel connection:

Here for each image 2 RTT are required one for TCP connection and one for image to send.
So transmit time for 30 images = 2*(30 RTT) = 60 RTT
Total time = 2 RTT+60 RTT = 62RTT

(ii) Non-persistent connection with 10 parallel connection:

Here 10 images can be send simultaneously.
So for 30 images it required -> 2*(30/10) = 6RTT
Total time = 2 RTT + 6 RTT = 8RTT

(iii) Persistent connection without pipelining:

Here TCP connection is required again and again.
So for 30 images it requires -> 30 RTTs
Total time = 2 RTT + 30 RTT = 32RTT

(iv) Persistent connection with pipe-lining:

Since it is Persistent connection TCP connection is not required again and again.
Pipe-lining means in one packet only images which can fit, can be send.
In Pipe-lining connection we can send all images in 1RTT.
Total time = 2 RTT + 1 RTT = 3RTT