Re: Hubs killing performance

Colin Johnston (colinj@uk.psi.com)
Fri, 5 Nov 1999 21:16:38 +0000 (GMT)

set the sparc and the NT box to not use auto detect as this
will help matters if auto negotiation is not working correctly

Colin Johnston
SA
PSINET UK

On Fri, 5 Nov 1999 spamhater03@birch.crd.ge.com wrote:

> I have a Windows NT client talking to a Solaris server.
> The CLient has a 10 MB/s card, the server has a 10/100 MB card.
> Using the TCP_TCP_STREAM benchmark, we got two different results:
>
> Using a cross-over cable (no hub) we got a value of 8.77
>
>
> C:\netperf>netperf -Hdemo -l60 -v2
> TCP STREAM TEST to demo
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 16384 8192 8192 60.00 8.77
>
>
>
> Adding a NDC SOHO 10/100 mb autosensing hub, the performance is now:
> C:\netperf>netperf -Hdemo -l60 -v2
> TCP STREAM TEST to demo
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 16384 8192 8192 61.00 1.80
>
>
>
> Why would a hub degrade the performance so much?
> Is it the auto-sensing?
> This is a simple hub with one switch (uplink on/off).
>