Looking for some education on ALTQ

[Morgan Wesström]

On 2010-07-21 02:21, Patrick Mahan wrote:
> I am the first to admit I don't understand ALTQ and it's impact on QoS but
> that said, I am trying to learn.
> 
> I have the following three systems.  All systems are running FreeBSD
> 8.0-p2 Release.
> I am attempting to learn how AltQ can be used to prioritized and setup
> banddwith
> pipelines.
> 
> At the end of this message is the topology and all (I hope) the relevent
> info for
> someone to help me understand what is happening.
> 
> I have setup AltQ on em0 on NPX3 with a queue set to run at 1.9Mbps. 
> However, in
> testing by generating UDP traffic on NPX4 and having it received on NPX3
> I am
> seeing (what I believe) to be really low throughput scores for queue
> test7788
> (see the pf.conf below).
> 
> pfctl -vv -s queue shows the bandwidth starts at 4.84 Kb/s, not 1.9 Mbps
> I was
> expecting.
> 
> Am I
> 
> 1. Not driving the datastream high enough to eat 1.9 Mbps (what should I
> run as
>    my iperf -b value?
> 
> 2. Miss configuring AltQ?
> 
> or
> 
> 3. There is a bug in AltQ?
> 
> Thanks for the education -
> 
> Patrick
> 
> 
> Network topology:
> 

According to the following PR, ALTQ doesn't work with em(4) in 8.0-p2. A
patch has been submitted for later versions but since I haven't upgraded
myself because of this issue, I'm not sure exactly what version you need.
http://www.freebsd.org/cgi/query-pr.cgi?pr=138392

Regards
Morgan