[CentOS] Bandwidth optimization
bazy at goofy.celuloza.ro
Mon Nov 5 08:30:58 UTC 2007
James A. Peltier wrote:
> 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
>> CentOS mailing list
>> CentOS at centos.org
> 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.
Yes you are right, we should prioritize ack's and dns requests (port 53)
at first. But this is CentOS not BSD, so we should use tc (show /
manipulate traffic control settings).
Ioannis Vranos: You should connect from a windows machine and check if
the ping reply and the download speeds are the same as on the linux
machine. If the windows machine proves to be faster, start debugging the
linux machine. 160-170 ms to your ISP's gateway seems a lot of latency
to me. I have a cable modem and an 6 ms latency to my ISP.
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