Re: Why does windows2000 ping have a resolution of 10ms?

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#126

From: Bob Cousins
Date: Sun, 10 Mar 2002 00:52

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Simon wrote:

>* Simon <usenet@sis-domain.demon.co.uk> wrote:
>> An Intel EtherExpress Pro 100 on Linux 2.4.5 using ping from netkit-base-0.17:
>> 
>> 64 octets from 158.152.1.222: icmp_seq=0 ttl=255 time=155.4 ms
>> 64 octets from 158.152.1.222: icmp_seq=1 ttl=255 time=140.0 ms
>> 64 octets from 158.152.1.222: icmp_seq=2 ttl=255 time=150.0 ms
>> ...results carry on accurate to 10ms until the ping is stopped
>
>To follow up my own post, this is over the PPP stack (using pppd 2.4.1) and
>not the NIC.  Must acquire more caffeine...

Ooops..

Actually, I am fairly certain the ping application calculates the time
interval, but it is possible the NIC driver affects the resolution,
for example depending on how interrupts get handled and how the
request queues are managed.

Linux source code is obviously freely available, if you look at the
source to ping you will see it uses the system timer. The Unix socket
interface does not carry timestamps of packets. Winsock derives from
the Unix socket API, so is similar.
-- 
Bob Cousins.
Please remove $NOSPAM$ to reply.

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From: Bob Cousins <bob@$NOSPAM$lintilla.demon.co.uk>
Newsgroups: demon.ip.support.nt,demon.service.isdn
Subject: Re: Why does windows2000 ping have a resolution of 10ms?
Date: Sun, 10 Mar 2002 00:52:41 +0000
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