Date: Fri, 25 Jul 2003 23:09:11 +1000 From: Mark Hannon <markhannon@optusnet.com.au> To: freebsd-ipfw@freebsd.org Subject: using dummynet to simulate modem, dsl, etc Message-ID: <3F212BF7.4060602@optusnet.com.au>
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Hello,
I am trying to use dummynet to simulate different network links and
demonstrate
application level performance for a variety of scenarios. The first
test is three
ftp file transfers over a simulated 56k modem as per below:
iifconfig lo0 mtu 1500
fconfig lo0 alias 127.0.0.100
ipfw -q add 1 pipe 1 ip from any to 127.0.0.100
ipfw -q add 2 pipe 2 ip from 127.0.0.100 to any
ipfw -q pipe 1 config bw 33kbit/s queue 0 delay 40ms
ipfw -q pipe 2 config bw 56kbit/s queue 0 delay 112ms
The results seem strange ... larger file sizes seem to have a slower
transfer rate,
where I would have thought that steady-state transfers would have been
reached
for the larger files. Are these results logical? Have I done something
silly with the
pipe configs?
Receiving test_large (1937201 bytes): 100% (ETA 00:00)
1937201 bytes transferred in 551.1 seconds (3.43 kBps)
Receiving test_medium (248476 bytes): 100% (ETA 00:00)
248476 bytes transferred in 66.7 seconds (3.64 kBps)
Receiving test_small (40960 bytes): 100%
40960 bytes transferred in 7.3 seconds (5.52 kBps)
Regards/mark
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