[olug] Full Duplex - NIC

Kelly Williams kellywilliams81 at gmail.com
Thu Feb 4 06:59:50 UTC 2010


Will Langford wrote:
> On Wed, Feb 3, 2010 at 11:56 PM, Luke-Jr <luke at dashjr.org> wrote:
>
>   
>> On Wednesday 03 February 2010 08:24:09 pm Kelly Williams wrote:
>>     
>>> I checked my Nic on my server and it run full duplex. I noticed that I
>>> was running two machines with XDMCP disable it on both machines and
>>> still not getting any faster. I took off a switch on my network still
>>> not any faster. Any thoughts.
>>>       
>> One thing to consider is that if you're using TCP, there are ACK packets
>> going
>> the other way. Usually it shouldn't make a big difference, but if you're
>> sending lots of small packets, it could...
>>
>>
>>     
> Lots of tiny packets would be inherently slower, yup.
>
> Lowering your MTU to 1490 or similar can help some, especially if you're
> VLAN'ing.  As Luke suggested, google is your friendly.
>
> Conversely, if all of your network can handle it (or segmented bits can),
> jumbo frames (huge MTU over 1500) can also possibly benefit you a lot.
>
> Out of curiosity, what about your network is slower ? Certain things are
> 'inherently' slower.  SFTP stuff is typically 2-3MB/sec, Windows file
> sharing will also automatically chop your transfer speed in half over
> whatever medium you're using (ie: on a 115200 serial connection, you'll only
> get 5k/sec versus expected 11k/sec... or 512K/sec over 10baseT, etc).
>
> The iPerf/jPerf/etc tools mentioned by Rob is also a great idea.  Wire
> sniffers might be a last ditch effort to see what's going on, too.
>
> The only hardware related thing that comes to mind is that cheap NIC's can
> be flakey, but even worse is cheap hub/switches.  For example: an Encore
> branded switch is begging for performance and stability issues (we've noted
> it in the field).  Even some Netgear switches have issues...
>
> -Will
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>   
My router is netgear and the switch that is connected to the server is a 
smartstack. The server was a old emachine desktop runs sweet with linux 
sucks with windoz. It does make sence when transferring lots of small 
files it gets slower but when transferring ISOs over the network to the 
server it works nice. I created a digram of my network. 
http://www.flickr.com/photos/24514670@N04/4329806806/ the switch that is 
connected to the servers is smartstack switch and then the switch that 
is connected is a 5 port netgear switch and just a basic 45.00 netgear 
router. I was thinking that I should take out the netgear switch and run 
every thing on the smartstack. then have the router has just the 
gateway, just one cat5 to the smartstack switch. I believe that would 
get rid of bottle necks in my network. any advice. Thanks for the help.

Kelly,





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