Re: collecting fragmentation data on the iperf server

[Matthew J Zekauskas <matt --at-- internet2.edu>]

Fragmentation is a property of IP version 4 datagrams, and not
of UDP (or TCP) packets.  Thus, a user program never sees
the fragments (unless it is actually listening for IP datagrams
via the packet filter or something).  In any event, iperf
never sees fragments.

My suggestion would be to either poll the operating system
(for example, many Unix systems will have statistics in
"netstat -s" output, such as
    27 fragments dropped after timeout
    32928 reassemblies required
    29 packet reassembles failed
) or use tcpdump (or equivalent) to actually record packet
traces of iperf connections, and post-process to detect
fragments later.

--Matt


--On Wednesday, February 09, 2005 5:01 PM -0600 Manish S Mittal <manish81 --at-- uab.edu> wrote:

>
> Hi,
>    I wanted to test a wireless network with varying datagram packet sizes. Also one of the
> crieteria of the analyses is the fragmentation of the packets. Is there a way in iperf to collect
> the fragmentation data of the UDP packets? Looking forward to some advice.
>
> Thank you
> Manish Mittal