I am doing some testing of openwrt'd wireless access points, using
madwifi-ng'd atheros radios. In the test configuration, I have three
devices in a triangle, each has wds links to the other two devices.
The ath0 interface is in ap mode, ath1 is a wds link to one device,
and ath2 is a wds link to the other device. All three interfaces (and
an ethernet interface) are in a bridge (br-lan) with STP on. The
weird thing is that STP doesn't seem to ever block ports. The same
firmware is on all three devices, a 2.6.23.1 kernel built from a r9512
checkout of openwrt's SVN repository.
If I sniff the wds interfaces (ath1 and ath2) with tcpdump, I see STP
packets, e.g.:
<timestamp> STP 802.1d, Config, Flags [none], bridge-id
8000.<macaddr>
where ath1 and ath2 show the STP packets with the local bridge-id, and
ath1 *also* shows STP packets from the bridge-id of the bridge on the
other side of the ath1 wds link. ath2 does not show a second bridge-id.
The network is not completely stable. It gets out of whack
occasionally (under not-fully-characterized conditions) and doesn't
come back by itself, requiring strategic (random) power cycling until
it works again.
Clues?
device 10.11.63.4:
$ brctl show
bridge name bridge id STP enabled interfaces
br-lan 8000.00095bf7938d yes eth0.0
ath0
ath1
ath2
$ brctl showstp br-lan
br-lan
bridge id 8000.00095bf7938d
designated root 8000.00095bf7938d
root port 0 path cost 0
max age 20.00 bridge max age
50.00
hello time 2.00 bridge hello time
5.00
forward delay 0.00 bridge forward delay
0.00
ageing time 300.00
hello timer 1.26 tcn timer
0.00
topology change timer 0.00 gc timer
0.26
flags
eth0.0 (1)
port id 8001 state
forwarding
designated root 8000.00095bf7938d path cost 100
designated bridge 8000.00095bf7938d message age timer
0.00
designated port 8001 forward delay timer
0.00
designated cost 0 hold timer
0.25
flags
ath0 (2)
port id 8002 state
forwarding
designated root 8000.00095bf7938d path cost 100
designated bridge 8000.00095bf7938d message age timer
0.00
designated port 8002 forward delay timer
0.00
designated cost 0 hold timer
0.24
flags
ath1 (3)
port id 8003 state
forwarding
designated root 8000.00095bf7938d path cost 100
designated bridge 8000.00095bf7938d message age timer
0.00
designated port 8003 forward delay timer
0.00
designated cost 0 hold timer
0.23
flags
ath2 (4)
port id 8004 state
forwarding
designated root 8000.00095bf7938d path cost 100
designated bridge 8000.00095bf7938d message age timer
0.00
designated port 8004 forward delay timer
0.00
designated cost 0 hold timer
0.22
flags
device 10.11.63.5:
$ brctl show
bridge name 8000.000fb50e69e9 yes eth0.0
ath0
ath1
ath2
$ brctl showstp br-lan
br-lan
bridge id 8000.000fb50e69e9
designated root 8000.000fb50e69e9
root port 0 path cost 0
max age 20.00 bridge max age
50.00
hello time 2.00 bridge hello time
5.00
forward delay 0.00 bridge forward delay
0.00
ageing time 300.00
hello timer 1.68 tcn timer
0.00
topology change timer 0.00 gc timer
0.68
flags
eth0.0 (1)
port id 8001 state
forwarding
designated root 8000.000fb50e69e9 path cost 100
designated bridge 8000.000fb50e69e9 message age timer
0.00
designated port 8001 forward delay timer
0.00
designated cost 0 hold timer
0.66
flags
ath0 (2)
port id 8002 state
forwarding
designated root 8000.000fb50e69e9 path cost 100
designated bridge 8000.000fb50e69e9 message age timer
0.00
designated port 8002 forward delay timer
0.00
designated cost 0 hold timer
0.66
flags
ath1 (3)
port id 8003 state
forwarding
designated root 8000.000fb50e69e9 path cost 100
designated bridge 8000.000fb50e69e9 message age timer
0.00
designated port 8003 forward delay timer
0.00
designated cost 0 hold timer
0.65
flags
ath2 (4)
port id 8004 state
forwarding
designated root 8000.000fb50e69e9 path cost 100
designated bridge 8000.000fb50e69e9 message age timer
0.00
designated port 8004 forward delay timer
0.00
designated cost 0 hold timer
0.64
flags
device 10.11.63.6:
$ brctl show
bridge name bridge id STP enabled interfaces
br-lan 8000.000fb50e4fc4 yes eth0.0
ath0
ath1
ath2
$ brctl showstp br-lan
br-lan
bridge id 8000.000fb50e4fc4
designated root 8000.000fb50e4fc4
root port 0 path cost 0
max age 20.00 bridge max age
50.00
hello time 2.00 bridge hello time
5.00
forward delay 0.00 bridge forward delay
0.00
ageing time 300.00
hello timer 1.81 tcn timer
0.00
topology change timer 0.00 gc timer
0.81
flags
eth0.0 (1)
port id 8001 state
forwarding
designated root 8000.000fb50e4fc4 path cost 100
designated bridge 8000.000fb50e4fc4 message age timer
0.00
designated port 8001 forward delay timer
0.00
designated cost 0 hold timer
0.79
flags
ath0 (2)
port id 8002 state
forwarding
designated root 8000.000fb50e4fc4 path cost 100
designated bridge 8000.000fb50e4fc4 message age timer
0.00
designated port 8002 forward delay timer
0.00
designated cost 0 hold timer
0.78
flags
ath1 (3)
port id 8003 state
forwarding
designated root 8000.000fb50e4fc4 path cost 100
designated bridge 8000.000fb50e4fc4 message age timer
0.00
designated port 8003 forward delay timer
0.00
designated cost 0 hold timer
0.76
flags
ath2 (4)
port id 8004 state
forwarding
designated root 8000.000fb50e4fc4 path cost 100
designated bridge 8000.000fb50e4fc4 message age timer
0.00
designated port 8004 forward delay timer
0.00
designated cost 0 hold timer
0.76
flags
--
Russell Senior ``I have nine fingers; you have ten.''
seniorr@aracnet.com
