Stop-and-Wait-ARQ
Question 1 |
On a wireless link, the probability of packet error is 0.2. A stop-and-wait protocol is used to transfer data across the link. The channel condition is assumed to be independent from transmission to transmission. What is the average number of transmission attempts required to transfer 100 packets?
100 | |
125 | |
150 | |
200 |
Question 1 Explanation:
Total no. of re-transmissions for one frame, in general, is 1/(1-P) where P is probability of error.
So here it would be for one frame = 1/(1-0.2) = 1/0.8
So for 100 frames = 100/0.8 = 125
So here it would be for one frame = 1/(1-0.2) = 1/0.8
So for 100 frames = 100/0.8 = 125
Question 2 |
Suppose two hosts are connected by a point-to-point link and they are configured to use Stop-and-Wait protocol for reliable data transfer. Identify in which one of the following scenarios, the utilization of the link is the lowest.
Longer link length and lower transmission rate | |
Longer link length and higher transmission rate | |
Shorter link length and lower transmission rate | |
Shorter link length and higher transmission rate |
There are 2 questions to complete.