AltQ + ng_iface

Daniel O'Connor doconnor at
Fri Jul 29 09:59:53 GMT 2005

On Friday 29 July 2005 12:35, Julian Elischer wrote:
> I do this to great effect..
> consider:
> two sites connected by links in which teh bottleneck is 200KB/sec (1 E1?)
> when a lot of data is flowing from 1 to 2  then data from 2 to 1 is also
> slowed
> down because the acks have to go through the queues on ingress side of the
> bottleneck router.
> I add a dummynet entry on 1, limiting output to 190KB/sec, so that the
> queue is in dummynet and not the intermediate router, and then allow small
> ack packets
> to bypass that queue. As a result the data from 2 to 1 also flows at
> near capacity,
> and with a much lower latency. SInce data flows tend to be large packets,
> I sometimes actually prioitise ALL small packets allowing interactive
> stuff to
> bypass ftps etc. and sometimes I do it on both ends.

I am trying to do something similar, but for more interesting things like 
games ;)

ie prioritise game traffic at the expense of normal bulk traffic.

The problem is that you have to specify fixed pipe bandwidths so I need to run 
a script which reduces the size of the "everything else" pipe down to a level 
where it doesn't cause much delay.

It would be nice if there was a way of elevating the priority of the outbound 
game traffic above the bulk transfers - allegedly my ISP prioritises game and 
VoIP traffic on the way in to me...

My previous set up did work OK, but it was pretty limiting in that I had to 
really aggressively reduce non-game traffic bandwidth otherwise the game 
would get fairly laggy.

I am using 512/128k ADSL with PPPoE, and for non-crappy game play I need to 
limit incoming non-game traffic to 64kbit/sec and outgoing to 24kbit/sec.

Daniel O'Connor software and network engineer
for Genesis Software -
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
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