Go Back N ARQ,find no of re-transmissions needed


Station A wants to send 10 packets to station B using Go Back N ARQ, where N = 4. Moreover consider every 4 th packet lost while transmission (ACK’s from B never get lost). Calculate the number of transmissions that A has to make in GBN respectively to ensure safe delivery to B.


I am getting:-
Keep transmitting never end.
1,2,3,4(pkt lost), 5,6,7,4 (pkt lost) ,5,6,7,4(pkt lost),5,6,7… cont.