Cn

Question

station X needs to send a consisting of 12 packets to station Y using a sliding window(window size 4) and go back n error control stragedy.All packets are ready and immidiately available for transmission.If every 7th packet   that X transmits gets lost,then the no of packets that X will transmit for sending the message to Y are

Answer 1

Sequence num.	packet to be send
1	1
2	2
3	3
4	4
5	5
6	6
7(lost)	7
8	8
9	9
10	10
11	7
12	8
13	9
14	10(lost)
15	11
16	12
17	10
18	11
19	12

So ans should be 19