Ethereal-users: Re: [Ethereal-users] RTT Graph error

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: "Ronnie Sahlberg" <ronnie_sahlberg@xxxxxxxxxxxxxx>
Date: Tue, 4 Feb 2003 21:20:56 +1100
Your email client is broken. It posts emails in html/rich-text format.
Please repair it.


The TCP RTT calculations are working just fine.
If every second packet goes in the opposite direction and the congestion
window is only one segment
this is expected behaviour.


----- Original Message -----
From: Roger et Marie-Jos� Nicholls
To: Ethereal Users
Sent: Monday, January 27, 2003 6:55 PM
Subject: [Ethereal-users] RTT Graph error


As you can see in the table below, the RTT values (laboriously) measured off
the RTT graph are in fact nothing more than the "time since last packet" of
the next outgoing packet.
TCVAL and TCSECR values (which I have checked OK with Windump)  are ignored.

Packet    time since    TCVAL TSECR        Graph
            last packet                                    RTT value
315    0.250100        9290        7407    in    .189
316    0.189288        7456        9290    out
317    0.218539        9361        7413    in    .22
318    0.220896

True RTT values are several seconds.


On downloads with timestamp disabled, the RTT graph also shows this time to
next outgoing packet.

I'm using Windows 95, TCP1323=2, Ethereal set up file 0.9.8 downloaded 14
dec, and winpcap 3 0 a4.
Can anybody help?

Roger