[orbit-user] Detecting Wireless Collisions

[Rick Correa]

Does anyone know a good way to detect wireless collisions?

We tried looking at collisions as reported by ifconfig:
ath0      Link encap:Ethernet  HWaddr 06:60:b3:ac:2b:fe
                  inet addr:192.168.7.12  Bcast:192.168.255.255  Mask:
255.255.0.0
                  inet6 addr: fe80::460:b3ff:feac:2bfe/64 Scope:Link
                  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
                  RX packets:1016144 errors:0 dropped:0 overruns:0 frame:0
                  TX packets:22216 errors:0 dropped:0 overruns:0 carrier:0
                  collisions:0 txqueuelen:0
                  RX bytes:182508688 (174.0 MiB)  TX bytes:4129076 (3.9 MiB)


But it always returns 0.  If we get a packet capture, we see some packets
have the Retry bit set to 1 in the 802.11 frame.  Does this imply it is a
retransmission caused by a collision?  Is there any other way to get
collision stats?  We looked at iwlist and iwconfig but we couldn't find a
useful utility.  Perhaps something in /proc?
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