[c-nsp] Centos upload speed slower on 1000m than 100m over WAN links

[Paul]

Yeah I tried that.. I really think it's a problem with the linux kernel 
and e1000e driver and possibly either limited to that or an
incompatibility with cisco switch but I doubt that since i get such good 
speeds locally.  
I did some further testing and turned off all the checksum, segment 
offloads, frag offloads, etc that i could in the driver and it
gave me a much better but very unstable ranging 2-8MB/s.  It almost 
looks like it has a packet ordering issue, but only happens on 1000m, and
if that is the case this is the wrong forum to post on about that. And 
over a local link, the latency is so fast that it's not noticable, but 
once the latency
gets to 20-30ms and above it becomes worse.  Best guess so far. 

Arie Vayner (avayner) wrote:
> Paul,
>
> Gert's test should help us to see if there is any policing being done on
> the WAN link.
> The problem I am aiming at is not due to not enough BW, but due to
> dropping bursts due to policing (or not enough buffers, as Gert is
> referring).
>
> Another test to do, just to make sure this problem is coming from the
> WAN side, is to keep the server on the original access switch (not the
> 6500) and place your test client on the 6500. Can you please try that as
> well?
>
> Tnx
> Arie
>
> -----Original Message-----
> From: Gert Doering [mailto:gert at greenie.muc.de] 
> Sent: Sunday, June 27, 2010 12:06
> To: Paul
> Cc: Arie Vayner (avayner); cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Centos upload speed slower on 1000m than 100m over
> WAN links
>
> Hi,
>
> On Sun, Jun 27, 2010 at 04:55:20AM -0400, Paul wrote:
>   
>> Oh and to verify some things i used iperf and send big batch of udp 
>> traffic at 500mbit/s and it made it with 0.004% packet loss so the 
>> bandwidth through to the external link isn't the problem either..
>>     
>
> Can you go up to 1gbit/s on the Level3 link?  If they do some sort of
> policing, that would look like "a switch with small buffers".
>
> gert
> --
> USENET is *not* the non-clickable part of WWW!
>  
> //www.muc.de/~gert/
> Gert Doering - Munich, Germany
> gert at greenie.muc.de
> fax: +49-89-35655025
> gert at net.informatik.tu-muenchen.de
>
>   

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