Retransmissions in Consecutive duplicated ACK in TCP
<p>In the fast retransmission logic in TCP, TCP retransmit the packet when the sender gets the 3 duplicated ACKs. However, what if the sender gets 6 duplicated ACKS?</p>

<p>The following procedure is what I think,</p>

<p>1) sender sends lots of packets with big window size</p>

<p>2) the first packet is dropped</p>

<p>3) Receiver sends ACKS that contains the seq # of the first packets. And other ACKS will have same ack numbers. (For example, the sender send 1,2,3,4,5,6,7 and packet 1 is dropped. Then, the receiver sends ACKs 1,1,1,1,1,1,1) </p>

<p>4) The sender gets 3 dup acks and retransmit the dropped packet However, the receiver still sends 6 dup acks because the receiver doesn't get retransmitted packet. Therefore, the receiver will send duplicated ACK until it gets the dropped packet</p>

<p>5) The sender gets 3 dup acks again, and retransmits the packet again.</p>

<p>Therefore, the sender will retransmit the packet repeatedly. I thinks this is weird. Is there any problem in the above procedure (scenario) ?
Or is there any TCP logic that can prevent the above problem?</p>