Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Stop-and-Wait-ARQ
| Question 2 |
A link has a transmission speed of 106 bits/sec. It uses data packets of size 1000 bytes each. Assume that the acknowledgement has negligible transmission delay, and that its propagation delay is the same as the data propagation delay. Also assume that the processing delays at the nodes are negligible. The efficiency of the stop-and-wait protocol in this setup is exactly 25%. The value of the one-way propagation delay (in milliseconds) is ___________.
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| 13 | |
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Question 2 Explanation:
Given, B = 106bps
L = 1000
η = 25%
Tp = ?
In stop-and-wait, η = 1/1 + 2a
⇒1/4 = 1/1 + 2a ⇒ 1 + 2a = 4
2a = 3; a = 32
Tx = L/B = 8×103/106 = 8ms
Tp/Tx = 3/2; 2Tp = 3Tx
2Tp = 24ms
Tp = 12ms
L = 1000
η = 25%
Tp = ?
In stop-and-wait, η = 1/1 + 2a
⇒1/4 = 1/1 + 2a ⇒ 1 + 2a = 4
2a = 3; a = 32
Tx = L/B = 8×103/106 = 8ms
Tp/Tx = 3/2; 2Tp = 3Tx
2Tp = 24ms
Tp = 12ms
Correct Answer: A
Question 2 Explanation:
Given, B = 106bps
L = 1000
η = 25%
Tp = ?
In stop-and-wait, η = 1/1 + 2a
⇒1/4 = 1/1 + 2a ⇒ 1 + 2a = 4
2a = 3; a = 32
Tx = L/B = 8×103/106 = 8ms
Tp/Tx = 3/2; 2Tp = 3Tx
2Tp = 24ms
Tp = 12ms
L = 1000
η = 25%
Tp = ?
In stop-and-wait, η = 1/1 + 2a
⇒1/4 = 1/1 + 2a ⇒ 1 + 2a = 4
2a = 3; a = 32
Tx = L/B = 8×103/106 = 8ms
Tp/Tx = 3/2; 2Tp = 3Tx
2Tp = 24ms
Tp = 12ms
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