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

[Arie Vayner (avayner)]

Paul,

What kind of a link are you getting from Level3?
Could it be a subrate link (i.e. a GigE port with some lower bandwidth
service?)

Arie

-----Original Message-----
From: Paul [mailto:paul at gtcomm.net] 
Sent: Sunday, June 27, 2010 11:10
To: Arie Vayner (avayner)
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Centos upload speed slower on 1000m than 100m over
WAN links

Even plugged directly into edge router (cisco 6500) connected to level3 
and tested on another server on level3 5 hops away.
When the port is set at 100 i can get full 100m speed, when i set it at 
1g I get less, which makes absolutely no sense and I'm totally stumped.


Arie Vayner (avayner) wrote:
> Paul,
>
> I am not really aware of the fine details on the CentOS thingie, but
can
> you describe how the upstream network connection of that server looks
> like? What lies beyond the NIC in the next few network hops.
>
> Thanks
> Arie
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Paul
> Sent: Sunday, June 27, 2010 09:04
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] Centos upload speed slower on 1000m than 100m over
WAN
> links
>
> I'm not even sure this is the right forum but since we use mainly
Cisco 
> equipment I'll give this a shot. :)
> I have tried several centos based servers and compiled various kernels

> and the results have been extremely weird.
> 90% of the cases the remote hosts can download from a server at 
> 1-5megabytes per second, and most of these are over
> the internet ranging from 30-200ms away.  Local (1ms or less) is super

> fast 100MB/s for example. 
> Ok that sounds normal since it's going over the internet, etc.  But 
> here's the )(!@*! part..
> If I set the port speed to 100 megabits full duplex on the switch and 
> server , the clients that get 1-5MB/s now get 11MB/s which is
> approximately the limit of the 100mbit port. 
> Totally stumped here, tried different nics, servers, even 4 different 
> switches.  Is a very interesting problem and I'm probing to see
> if anyone else has encountered it. 
> So far the only OS i have tried is centos, but different versions and 
> kernels and hardware.
> All the switches/routers are Cisco based, but I seriously doubt that
has
>
> anything to do with this. :P
>
>   

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