[Madwifi-devel] Real throughput tests at 4.4km p2p link

[Beat M. <Bea...@gm...>]

Hello

Testconfig: both sites: SR5 cards, 22dbi grids, madwifi-svn-1457, no wep,
link distance 4.4km

Below are my test results but first some comments:

It seems that there is a huge difference if you use iperf client on the ap
site or sta site (see below).
If iperf client runs on ap and iperf server on sta I get about 28Mbps but if
iperf client
runs on sta and iperf server on ap I get only about 17Mbps.
I have only one client on all my tests. Is this limitation in the nature of
an AP or is
this a limitation of madwifi? This is also if the bitrate is fixed!

For example channel 149 tests, fix rate on both sites:
48M: 18.9 Mbps; -67dbm both sites; 20 hour test (iperf client runs on sta)
48M: 23.1 Mbps; -67dbm both sites; 2 hour test (iperf client runs on ap)


The best channel with SR5 is channel 149, other channels have about -3dbm
drops in signal with same bitrate fixed!

*********************************************
Bit Rate  Channel 157
Mb        Signal Client # Signal Server # Throughput (client on sta)

54       -70     # -71/-72 # 15 (Throughput client on ap: 24.8Mbps)
48       -68/-69 # -70/-71 # 16.5
36       -68     # -69     # 15.5
24       -67     # -67     # 12.7
6        -67     # -66/-67 # 4.03

auto
36-54 on ap (iperf server)  # 17.0Mbps
48 on sta (iperf client)

54 on ap (iperf client) # 28.0Mbps
36-54 on sta (iperf server)

*********************************************
Bit Rate  Channel 165
Mb        Signal Client # Signal Server # Throughput (client on sta)

54       -69/-70 # -70     # 17  
48       -68/-69 # -68/-69 # 18.6
36       -67/-68 # -67/-68 # 16.3
24       -66/-67 # -65/-64 # 12.7
6        -66/-67 # -65/-64 # 4.03

auto
36-54 on ap (iperf server)  # 18.7Mbps
36-48 on sta (iperf client)

or
48 on ap (iperf client) # 24.5Mbps
54 on sta (iperf server)
*********************************************

The constelation iperf client on ap is much more "stable"  i.e. bitrat does
not change as much as if client is running on sta!
But this is not the problem of the lower throughpout because you can fix the
bitrate as noted and there is a hughe difference.
In the lower bitrates they are almost the same but in the higher there are
differences!!!

Here one of my lab test:

Lab tests, only 4m, Channel 149

client on AP, server on STA
54  23.8    -31
48  29.9    -28/-29
36  23.5    -27
24  16.4    -25/-26
18  12.9    -25/-26
12  8.5     -25/-26
9   6.6     -25/-26
6   4.37    -25/-26

client on sta, server on AP
54  19.2
48  18.3
36  16
24  12.8
18  10.7
12  8.0
9   6.6
6   4.69

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