This is our old Q&A Site. Please post any new questions and answers at

Hello Everyone!

I tried to understand why there is retransmision after getting ack picture1. Could anybody explain me why there is retransmission after getting correct ack? picture2

asked 22 Jun '15, 10:48

Kabun's gravatar image

accept rate: 0%

Well, the ACK number is the next expected sequence number by the receiver. So the server at 5001 has received all bytes up to 1595113 (tcp.nxtseq==1595113) and is now expecting the segment with tcp.seq==1595113. When wireshark flags it as a retransmission this indicates that it was lost in transit when it was initially sent.

alt text

So this is the same trace as in why-retransmission-occured-before-duplicated-ack if you filter tcp.nxtseq==1595113 or tcp.ack==1595113 or tcp.seq==1595113 and go to Statistics -> Flow Graph you see the relevant packets.

alt text

permanent link

answered 22 Jun '15, 11:27

mrEEde's gravatar image

accept rate: 20%

edited 22 Jun '15, 11:55

Thanks for the answer

(22 Jun '15, 11:40) Kabun

If you think that the question is answered to your satisfaction would you mind marking the given answer by clicking the checkmark icon ... That will close the question out. BTW maybe you can also close the other thread if it is the same issue ...

(24 Jun '15, 09:12) mrEEde
Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 22 Jun '15, 10:48

question was seen: 2,124 times

last updated: 24 Jun '15, 09:12

p​o​w​e​r​e​d by O​S​Q​A