[CentOS] Bandwidth optimisation

[James A. Peltier]

Barry Brimer wrote:
> 
> 
> On Mon, 5 Nov 2007, Ioannis Vranos wrote:
> 
>> OS: CentOS 5.0 x86.
>>
>> Hi, I am using CentOS 5.0 at home, ADSL ~16 Mbps/~1 Mbps Internet 
>> connection and my ping time to my ISP is 160-170 msec.
>>
>> When downloading something with Firefox, I am getting download speeds 
>> of about 100-180 KB/sec (for example when downloading SP2 of XP from 
>> MS server).
>>
>> Are the CentOS networking settings OK for this kind of latency, or do 
>> I have to change some settings?
> 
> I am using this on my CentOS 4 machine.  I would expect it to work on a 
> CentOS 5 machine as well.
> 
> Add the following to /etc/sysctl.conf
> 
> net.core.rmem_default = 67108864
> net.core.wmem_default = 67108864
> net.core.rmem_max = 67108864
> net.core.wmem_max = 67108864
> net.ipv4.tcp_mem = 4096 67108864 67108864
> net.ipv4.tcp_rmem = 4096 67108864 67108864
> net.ipv4.tcp_wmem = 4096 67108864 67108864
> 
> Run sysctl -p
> 
> Barry
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You may want to consider adding QoS to ACKs.  Giving ACKs higher 
priority will allow you to better utilize the link by ensuring they 
don't get overrun with other traffic.  I do this on my OpenBSD firewall 
with great success.

-- 
James A. Peltier
Technical Director, RHCE
SCIRF | GrUVi @ Simon Fraser University - Burnaby Campus
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