Sliding window, Go-Back-N protocol, All ack lost case

Question

I understood that receiver will correctly discard the frames in GBN all ack lost case. But its given that its positive ack and hence receiver wont send ack for discarded frames.Wont the sender be sending the same frames again and again after every timeout as receiver will never send ack again? So how will the sender slide the window to the next frames?

Comments

That's a worst case scenario! I think It stop retransmit after sometime... It will go into reset mode i think...

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can u explain reset mode? will it slide the window to next frames automatically after few times or drop the entire transmission?

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UDP type of protocalls will send next packets even though previous packets got dropped[EXAMPLE live cricket]  but it won't happen in TCP prtocals.. every packet must be delivered in TCP ,then that case only window will be moved right side

Answer 1

See these all are connection oriented protocols!. So if Sender is experiencing that nothing is working perfectly [ retransmitting repeatedly] then it will think that something bad is happened [link Down or something else] , so it will stop retransmissions , and transmit agian after some random amount of times , if this also not working then again retransmit after some random amount of time agin if this is also creating problem then it will reset the entire transmission process and it will start from the Scratch [ connect establishment] ,.. during connection establishment if we didn't recieve any acknowledgement from reciever to establish connection then it will think that there is problem in server side[may be in the network] so it will terminate the connection worst case

Comments

what i understood is that if all ack is lost there is no way the sender is sliding the window. Instead what is does it after a set amount of retransmissions it will terminate the transmission and try again after a particular time. But i thought it will correctly discard and there will be some way to slide the window.

Do you know any references as some resource material this case?

Answer 2

what happens if all the ACKs are lost. In that case, the sender will not receive any ACKs for the packets it has sent, and will eventually timeout for each packet in the window. Then it will retransmit all the packets in the window again, until it receives an ACK from the receiver. The receiver will keep discarding any packets that are not in order and send duplicate ACKs for the last correct packet it received. This will continue until either an ACK reaches the sender or the sender gives up after a certain number of retries.