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

i would like to know how wireshark is calculating rtt? is it cosidering delayed ack's, piggybacked acks and retransmitted packets.If it is not considered how do i incoorporate/filter these in calcuting rtt

asked 07 Jun '13, 00:49

SThomas's gravatar image

accept rate: 0%

converted 07 Jun '13, 01:48

grahamb's gravatar image

grahamb ♦

The Wireshark initial Round Trip Time (iRTT) value is calculated when the first two packets of a TCP handshake are seen {SYN, SYN/ACK}. This value will remain the same for the entire TCP conversation. {tcp.analysis.initial_rtt}

When you graph RTT in an IO graph, latency times are depicted between a data packet and the subsequent acknowledgment packet.

You can always do your own handshake analysis and filter on {tcp.flags.syn==1} to find the start of the conversation and then set time deltas to calculate individual session RTTs.

permanent link

answered 08 Nov '16, 09:57

BruteForce's gravatar image

accept rate: 9%

It takes the send time (ack) - send time (packet, that is, tcp)


permanent link

answered 07 Nov '16, 09:58

Josh123456789's gravatar image

accept rate: 0%

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: 07 Jun '13, 00:49

question was seen: 23,762 times

last updated: 08 Nov '16, 09:57

p​o​w​e​r​e​d by O​S​Q​A