netstat byte/bit confusion

[Miroslav Lachman]

Steve Bertrand wrote:
> Hey all,
> 
> I'm experiencing conflicting information on throughput numbers when
> comparing information garnered via MRTG on a 1000Mbps HP Procurve, and
> netstat -h -w1 on a server connected to the switch.
> 
> What I want to know is if netstat in the below case is actually
> displaying the info in bits, even though it is telling me the result is
> in bytes:
> 
> amanda# netstat -h -w1
>             input        (Total)           output
>    packets  errs      bytes    packets  errs      bytes colls
>       109K     0        90M        200     0        14K     0
>       104K     0        88M        201     0        14K     0
> ^C
> 
> On a different server running MRTG (FBSD 7.0-STABLE), I have configured
> it to display in bits/s, and it is showing ~90Mbps.
> 
> Which one is accurate? I'm trying to evaluate the difference between
> Cisco Cat 29xx 100Mb switches and this ProCurve GigE 2848 switch. So
> far, my results are that the 100Mb Cisco can peak and sustain a 98Mbps
> throughput.
> 
> The Procurve, unless MRTG is wrong, and netstat output should be 90M*8,
> I'm far less than impressed.
> 
> ...or could it be that MRTG is broken/capped at ~100Mbps calculations?
> 
> Thanks for any insight,

If you are using MRTG with SNMP info from switch, be aware of 32 bit 
counters. If you have high network load on the switch, the counter 
overflows between two five minutes intervals of MRTG and then MRTG shows 
inacurate results. (for example 60Mbps instead of 250Mbps peak)

Some devices have 64 bit counters and MRTG can be configured to use these.

netstat is in bytes AFAIK.

Miroslav Lachman