Can anyone explain - IPSec latency

Howard Lowndes lannet at lannet.com.au
Wed Feb 20 07:29:27 EST 2002


Yes, I see that, but the base latency is a component of the communications
media whereas the additional tunnel latency should not be a component of
the communication media but solely of the gateway computer.

The only consideration might be modem compression, or lack of it.

On 20 Feb 2002, Damien Elmes wrote:

> Howard Lowndes <lannet at lannet.com.au> writes:
>
> > Can anyone explain, or even guess, why the difference between ex-tunnel
> > and in-tunnel ping times is so much more when the link is ADSL to PSTN -v-
> > ADSL to ADSL.  I know why the base latency is greater, but that doesn't
> > explain the difference in latencies.  All machines at the gateways are
> > comparable (typically mid-range Celerons).
> >
> > Typically:
> >
> > ADSL to ADSL (3 cases) ex-tunnel=65msec in-tunnel=80msec diff=15msec
> > ADSL to PSTN (1 case)       "    185         "    235      "  50
>
> i've absolutely no idea, to be honest. however, if we take the pecentage
> increase in latency for these first two:
>
> 15/65 * 100
> 23.07692307692307692300
>
> 50/184 * 100
> 27.17391304347826086900
>
> we see that in both cases, we're getting an increase in latency of roughly 25%
> i'm a hopeless mathematician, so i'm probably glossing over something here..
>
>

-- 
Howard.
LANNet Computing Associates - Your Linux people
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