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packets are being transmitted using GB5 and here every 4th packet is lost.How many packets need to be transmitted to transmit 10 packets?

my answr 18 given :20
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6 Answers

7 votes
7 votes
Since, window size is 5, all first 5 packets will be sent continuously. After receiving acknowledgements, window will be slided. When timeout occurs, entire window will be retransmitted again.

12345

[45678] - 4th packet in previous transmission is lost. When timeout occurs, window will be like this. So, this window is retransmitted as below.

[45678] - 8th packet loss in previous transmission will be ignored as expected ack is for 4th packet.

[78910] - 7th packet in previous transmission is lost. When timeout occurs, window will be like this. So, this entire window is retransmitted.

[78910] - Again 7th packet in previous transmission is lost.

[78910]

[78910]...

The last window will be in transmission forever. So question is wrong.
1 votes
1 votes
123(45678)[now 4 lost so again transmit the whole window size]

       45678910[ here the 4th transmission 7 will be lost]

             78910[ now again the 4th transmission packet lost i.e 10 so transmit 10]

                     10

so total 20
0 votes
0 votes
Yes, 7th packet will always be lost.

The last window (7(lost) 8 9 10) will be sent again and again.

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