I have following doubt regarding Fast retransmitting. First of all i will Explain Fast retransmit.

Fast Retransmit-:If a sender has send packet P,P+1,P+2...P+N and let Packet P is lost ,Now Reciever is expecting Packet P.Reciever will send 3 Duplicate Ack to sender "expecting Packet P".Sender on recieving 3 Duplicate Ack,Retransmit Packet P.

My doubt-:

  • What Happens to Packet P+1,P+2,...,P+N ?
  • Do sender Need to retransmit Packet P+1,P+2....P+N also??

Full process in details is described in RFC 2581 3.2

The fast retransmit enhancement works as follows: if a TCP sender receives a specified number of acknowledgements which is usually set to three duplicate acknowledgements with the same acknowledge number (that is, a total of four acknowledgements with the same acknowledgement number), the sender can be reasonably confident that the segment with the next higher sequence number was dropped, and will not arrive out of order. The sender will then retransmit the packet that was presumed dropped before waiting for its timeout.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.