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Thread: Gigabit transfer speeds




Gigabit transfer speeds
user name
2006-08-21 12:42:10
Dan Hunter wrote:

> I regularly move large files from a windows XP machine
to a Fedora 
> Core 5 machine.
> To avoid bothering other network users, I purchased two
Linksys EG1032 
> gigabit ether net cards.
> The cards have been installed.  a direct PC to PC
gigabit cross over 
> cable connects them.
> A separate set of IP address have been set up.
> I can verify that data is being transfered over the
gigabit cable with 
> windows task manager.
>  
> Transfers over the 10/100 link show up at 82 or 83
percent - about 80 
> Mbps.
> Transfers over the gigabit link show up at 20 to 26
percent - about 
> 230 Mbps.
>  
> What do I have set up wrong?
>  
>
Your expectations are to high. If you have about 20%
utilisation with a 
Gbit nic, I'd say you are doing verry nice.

With the move to gigabit networking, the nic is no longer
the 
bottleneck. If you move data from disk on one machine or to
disk on an 
other, the disk-controllers, disk interfaces or even the
actual disks 
are most likely the bottlenecks. Then, the disk does not
need to be the 
bottleneck. Think about the speed of internal busses and for
which they 
are used while you are dumping data...


CBee

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Gigabit transfer speeds
user name
2006-08-21 18:37:36
Increase your packet size...

One of our networking class projects a couple years ago was to benchmark gigibit ethernet transfer speeds. 

I benchmarked 700mb/s+ between two Linux PCs which was reasonable to our instructor.

He emphasized that the brand/chipset of cards made a big difference ( it wasn't the most expensive that performed best ... ) as well as the drivers.

Some of his published tests as described below show that you can achieve at least 700mb/s even with 32bit Netgear GA622T cards as illustrated in a ps link from his website:

http://www.cs.uni.edu/~gray/

Benchmark project links:
http://www.cs.uni.edu/~gray/gig-over-copper/
http://www.cs.uni.edu/~gray/gig-over-copper/gig-over-copper.html

PS file showing performance benchmarks ( note 700mb/s+ requires packet size of 100k+ bytes ):

http://www.cs.uni.edu/~gray/gig-over-copper/hsln-lcn.ps

Tim

On 8/21/06, Corne Beerse <gmail.com">cbeersegmail.com> wrote:
Dan Hunter wrote:

&gt; I regularly move large files from a windows XP machine to a Fedora
>; Core 5 machine.
&gt; To avoid bothering other network users, I purchased two Linksys EG1032
>; gigabit ether net cards.
&gt; The cards have been installed.  ;a direct PC to PC gigabit cross over
> cable connects them.
> A separate set of IP address have been set up.
> I can verify that data is being transfered over the gigabit cable with
> windows task manager.
&gt;
> Transfers over the 10/100 link show up at 82 or 83 percent - about 80
> Mbps.
> Transfers over the gigabit link show up at 20 to 26 percent - about
> 230 Mbps.
>;
> What do I have set up wrong?
>;
>
Your expectations are to high. If you have about 20% utilisation with a
Gbit nic, I'd say you are doing verry nice.

With the move to gigabit networking, the nic is no longer the
bottleneck. If you move data from disk on one machine or to disk on an
other, the disk-controllers, disk interfaces or even the actual disks
are most likely the bottlenecks. Then, the disk does not need to be the
bottleneck. Think about the speed of internal busses and for which they
are used while you are dumping data...


CBee

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--
Tim Schoenfelder
http://timschoenfelder.com
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