From: David Randelman (davidr_at_nonexisting.hamakor.org.il)
Date: Mon 23 Jan 2006 - 15:12:22 IST
Alex,
From my experience the main problem is believe it or not your download
speed as well, the ISP creates huge buffers of data being sent to you.
If you want low latency you will have to disable the ISP downlink buffer
or at least reduce it, normally from my experience a 1.5Mbit line needs
to be reduced by half at least. Once you have done this you will have
much lower latency.
If you are wondering why this happens it is because while your uplink
is not saturated any more, believe it or not a saturated downlink will
cause the same effect. The problem is while you have control over your
uplink buffer, you can not control what the ISP sends you. The only true
method is use of TCP window manipulation or use of the MRQ module which
does the same as HTB, tries to define priorities on accepting packets
and droping others so the ISP will "understand" you are not able to
accept and reduct the TCP window size.
To make a long story short, you will not be able to obtain a fast
download stream AND hope to obtain minimum latency for gaming unless you
use tc to cut your bandwidth by half or more and at the same time it
will help to place the MRQ module.
Another important thing, using all the HTB/MRQ modules can create packet
buffer problems with pptp which already has its own buffering, if you
see errors in your /var/log/messages or dmesg coming from pptp then make
sure to disable the buffer (pptp --nobuffer)
Cheers,
-David
Alex Alexander wrote:
>On Monday 23 January 2006 13:42, you wrote:
>
>
>>Alex Alexander wrote:
>>
>>
>>>Greetings everyone,
>>>
>>>I'll try to keep it short. I have a linux routing machine connecting my
>>>384kbps adsl line (eth1) with my local network (eth0). Its running Debian
>>>unstable, w/ kernel 2.6.15 and the usual services (proxy, dns, dhcp, etc
>>>etc).
>>>
>>>I am trying to shape traffic, both incoming and outgoing, to avoid high
>>>latency in games like Battlefield 2 and Star Wars Galaxies whenever
>>>someone on the network decides to do anything internet-related.
>>>
>>>
>>I don't know the solution to your exact problem, but how about just
>>trying an existing script that is known to work? I used wondershaper and
>>it worked perfectly for me, it is simple to setup and known to do the
>>work properly.
>>
>>You can tweak it after you get it working to do anything special you want.
>>
>>Baruch
>>
>>
>
>Thanks, I will try wondershaper ( http://lartc.org/wondershaper/ ).
>
>However I forgot to mention that I have already tried to use Shorewall's
>built-in tc support with no luck...
>
>I'll get back to you with my results :)
>
>Alex
>
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