tcptrace RTT caltulation

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tcptrace RTT caltulation
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[email=uaca@alumni.uv.es?subject=Re:%20tcptrace%20RTT%20caltulation&replyto=20021113202225.GA19007@pusa.informat.uv.es]uaca@alumni.uv.es[/email]
Date: 11/13/02

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Date: Wed, 13 Nov 2002 21:22:25 +0100
Subject: Re: tcptrace RTT caltulation
Message-ID:
From:
[email=uaca@alumni.uv.es?subject=Re:%20tcptrace%20RTT%20caltulation&replyto=20021113202225.GA19007@pusa.informat.uv.es]uaca@alumni.uv.es[/email]
On Wed, Nov 13, 2002 at 12:39:57PM -0500, Liangping Ma wrote:
> Hi, Ulisses,
>
>     I did TCP RTT measurement before. Based on my memory, the tcptrace
> processes tcpdump raw data, which can be collected in a local ethernet.
> You are right, that the measurement may not be on one of the end points
> of a TCP conneciton. But the delay within a LAN is trivial in the case of
> a long-haul TCP connection. Thus the measurement can be reasonably
> accurate.
Ok, imagine the following two scenarios
         |
         |
[Host A]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
[Host B]
         ((((((((((((((((((((((((((
                                                             |
                                                             |
[Host A] ))))))))))))))))))))))))))))))))))))))))))))))))))))> [Host B]
         ((((((((((((((((((((((((((((((((((((((((((((((((((((>
>
> Liangping
>
> On Wed, 13 Nov 2002
[email=uaca@alumni.uv.es?subject=Re:%20tcptrace%20RTT%20caltulation&replyto=20021113202225.GA19007@pusa.informat.uv.es]uaca@alumni.uv.es[/email]
wrote:
>
> >
> > I have read rexmit.c:rtt_ackin() and I belive that RTT meassurement is the
> > following:
> >
> >
> >                          
> >                                    |
> >                                    |
> > [Host A]
))))))))))))))))))))))))))>>>>>>>>>>>>>>>>>>>>>>>>>>>
[Host B]
> >
((((((((((((((((((((((((((
> >
> >
> > ")" or ">" is the data segment
> >
> > "(" or "
> >
> >
> > Where the time meassured for RTT is the time that is the sum of ">" and "
> >
> > I suposse here the monitorization is being done in the "middle" of the connection
> >
> >
> > That is, tcptrace's RTT is not like the RTT meassured in the "ping" utility,
> > in other words is not a "two full way transmision" meassurement
> >
> >
> >
> >
> > Thanks in advance
> >
> >
> >         Ulisses
> >
> >
> >                 Debian GNU/Linux: a dream come true
> > -----------------------------------------------------------------------------
> > "Computers are useless. They can only give answers."            Pablo Picasso
> >
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http://www.valux.org/
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> >
> > ----------------------------------------------------------------------------
> > To unsubscribe, send a message with body containing "unsubscribe tcptrace" to
> > majordomo@tcptrace.org.
> >
>
--
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