This is on a WLAN interface rather than USB, but is definitely is NOT
truncated to 10ms and appears to match very closely the DOS ping results
(ethereal time is delta from previous packet).
Pinging yahoo.com [66.94.234.13] with 32 bytes of data:
Reply from 66.94.234.13: bytes=32 time=37ms TTL=52
Reply from 66.94.234.13: bytes=32 time=51ms TTL=51
Reply from 66.94.234.13: bytes=32 time=58ms TTL=52
Reply from 66.94.234.13: bytes=32 time=54ms TTL=51
No. Time Source Destination Protocol Info
1 0.003045 192.168.1.1 yahoo.com ICMP Echo (ping)
request
2 0.037259 yahoo.com 192.168.1.101 ICMP Echo (ping) reply
3 0.967955 192.168.1.1 yahoo.com ICMP Echo (ping)
request
4 0.051055 yahoo.com 192.168.1.101 ICMP Echo (ping) reply
5 0.950601 192.168.1.1 yahoo.com ICMP Echo (ping)
request
6 0.058340 yahoo.com 192.168.1.101 ICMP Echo (ping) reply
7 0.943089 192.168.1.1 yahoo.com ICMP Echo (ping)
request
8 0.053979 yahoo.com 192.168.1.101 ICMP Echo (ping) reply
----- Original Message -----
From: "Tomas Brännlund (KI/EAB)" <tomas.brannlund@xxxxxxxxxxxx>
To: <ethereal-users@xxxxxxxxxxxx>
Sent: Thursday, September 15, 2005 10:59 PM
Subject: [Ethereal-users] Can I trust the timestamps
Hello!
I wonder if someone could help me with an Ethereal timestamping problem.
We made some tests with a mobile terminal connected to a PC via USB. The
mobile terminal was connected to internet. We ran ping tests from the
computer and at the same time we logged the USB port with Ethereal. We ran
the Ping tests from an MS-DOS window. When we compared the Ping result
presented on the MS-DOS window with that logged with Ethereal there was a
difference. It seemed like Ethereal truncated the result down to multiples
of 10 milliseconds (rather: when taking the difference between ICMP request
and response the difference was always multiples of 10ms). To give an
example: the MS -DOS window could present results ranging from 90ms up to
120ms. There were no steps, i.e. all values between 90 and 120ms seemed to
appear (e.g. 90ms, 92ms, 96ms, 99ms etc). When looking at the ethereal
results, they showed either 80ms, 90ms or 110ms, in those exact steps. Could
someone please explain this behaviour.
I sent this question a few weeks ago without any response. But I am still
hoping someone can help me!
Thanks/Tomas Brannlund
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