[altq 1382] Re: Need help: PRIQ Details

["Tippyarat Tansupasiri" <fon@cs.ait.ac.th>]

Dear Nicolas,

Thank you very much for your suggestions. That helps me a lot. At least it
would not be a nightmare tonight :>

Tippyarat T.

----- Original Message -----
From: "Nicolas Christin" <nicolas@cs.virginia.edu>
To: "ALTQ Mailing-List" <altq@csl.sony.co.jp>
Sent: Friday, March 01, 2002 12:42 AM
Subject: [altq 1381] Re: Need help: PRIQ Details


> On Fri, 1 Mar 2002, Tippyarat Tansupasiri wrote:
>
> > What should be the size of your very very small packet?
>
> Well - you probably want to try with packets less than 512 bytes.
> Actually, the smaller, the better, for your purposes. See if you can
> generate 128-byte packets or even smaller for instance.
>
> > I used "Iperf" program to gernate those UDP flows with 1470 byte
datagram
> > size and 9 KByte buffer size (their default values). As stated in Iperf
> > document, Iperf "create a constant bit rate UDP stream" which is
"similar to
> > voice communication".
>
> I've never used Iperf myself, but based on what you are saying, I
> think you should try with a larger buffer and a smaller datagram size.
> It is extremely possible that, due to PRIQ, the buffer of your high
> priority class gets emptied and that no high priority packet is available
> for transmission. Basically, it looks to me like your source is not
> sending fast enough...
>
> > All links used in the experiment are Ethernet (100Mbps and 10Mbps). The
> > result is based on 1 second statistic (command -> altqstat -w 1). I
> > understand the point that the monitoring window should be small, but 1
> > second is the least I can specified, right?
>
> At this time, yes, 1 second is the smallest interval.
>
> > Should I try any other settings or traffic generators? Could you please
> > suggest?
>
> There are a bunch of traffic generators linked on
>
> http://www.caip.rutgers.edu/~arni/linux/tg1.html
>
> I personnaly stick with netperf, since a lot of people use it, and almost
> everything is configurable, but some people do not like it. You may want
> to try ttcp. (As far as I remember, ttcp can generate UDP traffic.)
>
> --Nick
>