maximum wireless speed config

[Andy Barlak]

Cannot get max speed from AP-STA setup.

Each AP runs
Soekris 4511, NL-2511CD Plus Ext, pebble.v39.
wlan0: NIC: id=0x800c v1.0.0
wlan0: PRI: id=0x15 v1.1.1
wlan0: STA: id=0x1f v1.7.4


level 3 :
master<->managed (AP-STA)

level 2 bridging modes that run:
master-wds<->master-wds (bridge)
repeater-wds<->repeater-wds (bridge)

The two radios are about 5 meters apart, different floors in a wood frame
building.

Using the iperf tool for bandwidth measurements between bridges:

[  5] local 192.168.0.152 port 1024 connected with 192.168.0.151 port 5001
[ ID] Interval       Transfer     Bandwidth
[  5]  0.0-10.1 sec  6.23 MBytes  5.17 Mbits/sec

ping:
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 3.3/3.6/4.1 ms

I understand that the max rate for a WDS links is one half the wireless
rate:  5.5 Mbit for a 11 Mbit link, so those results are expected.

When the radios are reconfigured for AP-STA operation, the bandwidth
results are still around 5.5 Mbit, when I expect to see 11 Mbit/sec.
What's the reason for that?

What has me really tied up is that a week ago, a transient configuration
setup produced ping times of about 1.2msec, and iperf results of 11Mbit
for the master-managed AP-STA setup.
(transient means I can't reproduce the configuration again.)

As an aside,  I discovered that ping times wouldn't go under 10ms
until I turned off "daemontools" in pebble.  Currently ps shows:
  PID TTY      STAT   TIME COMMAND
    1 ?        S      0:06 init [2]
    2 ?        SW     0:00 [keventd]
    3 ?        SWN    0:03 [ksoftirqd_CPU0]
    4 ?        SW     0:00 [kswapd]
    5 ?        SW     0:00 [bdflush]
    6 ?        SW     0:00 [kupdated]
  124 ?        S      0:00 /sbin/cardmgr -C config-2.4 -f
  173 ?        S      0:00 /sbin/syslogd -p /rw/dev/log -m 0
  176 ?        S      0:02 /sbin/klogd
  187 ?        S      0:00 /usr/sbin/sshd
  191 ?        S      0:00 /usr/sbin/cron
  192 /rw/dev/ttyS0 S   0:00 /sbin/getty -L ttyS0 19200 vt100
  193 ?        S      0:01 /usr/sbin/sshd
  195 pts/0    S      0:00 -bash

What is the reason AP-STA mode won't get me up to 11 Mbit ?

--------------------
Setup for master mode:
# this file is  interfaces-AP

auto lo
iface lo inet loopback

#------- This is an access point, the hostap wlan0 is set as master.
#

auto wlan0
iface wlan0 inet static
      address 192.168.1.154
       netmask 255.255.255.0
        broadcast 192.168.1.255
        wireless-essid broughton
        wireless-channel 11
        wireless-mode master
        pre-up prism2_param wlan0   basic_rates 15
        pre-up prism2_param wlan0   oper_rates 15
        pre-up iwpriv wlan0 bridge_packets 1

auto eth0
iface eth0 inet static
address 192.168.0.152
netmask 255.255.255.0
broadcast 192.168.0.255

---------------------
Setup for managed mode:
# this file is  interfaces-STA

auto lo
iface lo inet loopback

#------- This is an wireless client, the hostap wlan0 is set as managed.
#

auto wlan0
iface wlan0 inet static
      address 192.168.1.153
       netmask 255.255.255.0
        broadcast 192.168.1.255
        wireless-essid broughton
        wireless-channel 11
        wireless-mode managed
        pre-up prism2_param wlan0   basic_rates 15
        pre-up prism2_param wlan0   oper_rates 15
        pre-up iwpriv wlan0 bridge_packets 1

auto eth0
iface eth0 inet static
address 192.168.0.151
netmask 255.255.255.0
broadcast 192.168.0.255
-------------------------------------


-------------------------------------------------------------------------------
 Andy Barlak