Re: [e2e] query reg improving TCP performane

Greetings Zaman,

On 05/07/07, query <query.cdac@gmail.com> wrote:

> I am finding another problem. The UDP transmission rate on that link is
> decreased.
>
> iperf -u -c 192.168.60.62 -t 300 -l 1460 -i 2
> ------------------------------------------------------------
> Client connecting to 192.168.60.62, UDP port 5001
> Sending 1460 byte datagrams
> UDP buffer size: 108 KByte (default)
> ------------------------------------------------------------
> [ 3] local 10.128.0.2 port 32785 connected with 192.168.60.62 port 5001
> [ ID] Interval Transfer Bandwidth
> [ 3] -0.0- 2.0 sec 257 KBytes 1.05 Mbits/sec

To send UDP at a rate higher than 1Mbps, you need to specify -b to iperf. Unlike TCP, UDP doesn't "probe" for bandwidth, so you have to specify the rate you want to send at. From iperf -h:

    Usage: iperf [-s|-c host] [options]

           iperf [-h|--help] [-v|--version]     Client specific:

      -b, --bandwidth #[KM]    for UDP, bandwidth to send at in bits/sec
                               (default 1 Mbit/sec, implies -u)

Cheers,
Lachlan

-- 
Lachlan Andrew  Dept of Computer Science, Caltech
1200 E California Blvd, Mail Code 256-80, Pasadena CA 91125, USA
Phone: +1 (626) 395-8820    Fax: +1 (626) 568-3603