Ethereal-users: RE: [Ethereal-users] Throughput with Gigabit Ethernet

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Date: Thu, 10 Jul 2003 18:49:27 +0100
Martin,

The answer is (of course).... it depends.  Here's what I've found from my
testing.

1) Getting more than 40Mbit/s over any medium with NT/Win2K/XP with
negligible packet loss is impossible.  I'm not sure what the limitation is
but it can't be libpcap as Windump is better than tethereal at this . Here's
an example tracing the same UDP stream with WinDump and tethereal.

d:\>WinDump -n -s 0 -i \Device\NPF_{C0BD2FFE-AB2B-4F7E-B9A7-25B6B232EA29} -B
10000 -w test.cap
WinDump: listening on \Device\NPF_{C0BD2FFE-AB2B-4F7E-B9A7-25B6B232EA29}

1435240 packets received by filter
0 packets dropped by kernel

d:\>tethereal -i \Device\NPF_{C0BD2FFE-AB2B-4F7E-B9A7-25B6B232EA29} -n -q -w
test.cap 
Capturing on \Device\NPF_{C0BD2FFE-AB2B-4F7E-B9A7-25B6B232EA29}
416784 packets dropped
159952 packets captured

2) I have captured more than 2.4 Gbit/s over the loopback address on Linux.
I needed to write to a RAMdisk to achieve this but it worked fine until the
2GB RAM disk filled up. [Then things went very bad :-)]

3) I have captured at 250Mbit/s for 3 minutes over Gbit, but this was
limited by the CPU of the capturing box which was also running the
application generating the traffic.  

Hence I believe (but have not tested) that ethereal will, on Linux, with the
right CPU and fast enough disk, capture at wire speed 1Gbit/s. 

YMMV on Windows
 
Alistair

> -----Original Message-----
> From: Martin Kowalewski [mailto:martin@xxxxxxxxxxxxxxx] 
> Sent: 10 July 2003 16:23	
> To: ethereal-users@xxxxxxxxxxxx
> Subject: [Ethereal-users] Throughput with Gigabit Ethernet
> 
> 
> Has Anyone tested capturing packets at speeds greater than 
> 100MB, specifically Gigabit Ethernet?  If so how close to 
> line rate packet capture can ethereal get to?
> 
> Thanks,
> 
> Martin
> 
> _______________________________________________
> Ethereal-users mailing list
> Ethereal-users@xxxxxxxxxxxx 
> http://www.ethereal.com/mailman/listinfo/ether> eal-users
> 


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