Re: size of thepackets

Rick Jones (
Fri, 05 Nov 1999 16:00:32 -0800

Kiran Kumar Bhumana wrote:
> a couple of questions.
> 1) Can i change the size of the packets that i transfer on the
> net using the netperf program.

Not always. Remember that TCP is a _byte-stream_ and that users of TCP
should (generally) have no interest in or knowledge of the segment size.
TCP will break "large" user sends into segments, and combine small sends
into full-sizes segments.

UDP will had whatever you give it to IP, which will then fragment it as
needed. If your send size in a UDP test is smaller than the MTU-8 that
will generally be the packet size.

If you enable TCP_NODELAY (generally not a good thing to do), and your
sends are less than the MSS, that will generally be the packet size.

If your sends are larger than the MSS or MTU, the packet sizes will
depend on how much larger the sends are relative to the MTU/MSS.

> 2) Is there a way i can figure out the page size of the system? I
> am using Dell computers.

That is probably a function of the operating system. If it is running
Unix, getconf() may help.

> 3) How do i relate the elapsed time and through put?

Throughput = totalworkperformed/elapsed time

rick jones
> Thanks a lot,
> Res-(520) 792-9708
> T.A-(520) 621-8677

these opinions are mine, all mine; HP might not want them anyway... :)
feel free to email, or post, but please do not do both...
my email address is raj in the domain...