[Openvpn-users] Re: VPN & ADSL Adapter Speed Comparison

[Steve Shellswell <steve@xxxxxxxxxxxxxxxx>]

Leonard Isham wrote:
> On Wed, 22 Dec 2004 17:22:28 +0000, Steve Shellswell
> <steve@xxxxxxxxxxxxxxxx> wrote:
>
> > Dear all,
> >
> > I have two machines both connected via ADSL (512 down and 256 up) to the
> > Internet. On side is running an openvpn server (debian) and the other is
> > a client (Windows XP).
> >
> > Whilst on the client XP end pulling a few MB across the VPN, I was
> > looking at the Network Utilization tool that Win XP has (ctrl,shift &
> > esc) and was comparing the usage of the VPN adapter to the ADSL modem
> > adapter.
> >
> > The VPN adapter was sat right on about 2.5% usage and Windows thinks it
> > is 10Mbps. The ADSL adapter was pretty consistently on 13-15% and
> > windows thinks its maximum is 576kbps.
> >
> > 2.5% of 10Mbps is 256kbps and this looked good because the uplink on the
> > server end is 256, but 14% of 576kbps is about 80kbps.
> >
> > It therefore seemed to me that the VPN adapter was putting stuff through
> > at 256kbps. VPN was compressing it and transmitting down the real ADSL
> > adapter at around 80kbps. Am I right?
> >
> > Why then, for example, did VPN not use 90-100% of the available ADSL
> > line and get a throughput over the VPN adapter of three times 256? Is
> > there anyway to tell VPN to use all of the available link? Is it, do you
> > think, that XP cant count the usage properly?
> >
> > Many thanks for your thoughts....
>
>
> First since both sides are limited to 256 up your limitation is 256
> bidirectionally.

Yes

> Second what else is using the lines when you test?

mmm, nothing on the client end, server end not certain but I hadn't 
imagined much.

> Third are you actually reaching your purchased maximum or not?  Have
> you tried using dslreports to test?

I am reasonably confident to say that we get near the purchased maximum.

> Fourth What application(s) are in use what is their traffic patterns. 
> With FTP you get higher bandwidth on one direction with the other
> direction getting minimal usage.

Sage Accounting. When you load the Nominal window, the first time while 
it gathers data from the server takes about 3.5 mins, during which time 
I observed the numbers above.


Really my surprise was down to the VPN adapter putting through 256 and 
the real one 80. This is quite an impressive compression ratio. You 
might be right that servers other bandwidth was being used and so 
limited the ADSL to 80, and that it is then just coincidence that the 
VPN adapter was going at 256...

Steve


____________________________________________
Openvpn-users mailing list
Openvpn-users@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/openvpn-users