I have a long-standing problem that involves the iwi interface on
my Thinkpad T42 running 9.2-PRERELEASE circa 28 Aug 2013.

Some wifi connections I make show good signal strength, but poor
latency and/or packet loss to the WAP IP.  I can't find other
wifi users who perceive the wifi performance as poor, so I am
assuming the problem is local to me.

I will say this is generally repeatable by location: good
locations are usually good, bad locations are usually bad.  My
theory is that the 2200BG likes some WAPs that I use more than it
likes others.  I'd like to find out what I can do to either fix
the problem, or at least be able to accurately tell the WAP owner
what their problem is.

I'm ignorant about how to troubleshoot problems like this, so
please suggest some diagnostic information I can provide to guide
either of us toward a solution.

Thank you,


from dmesg:

iwi0: <Intel(R) PRO/Wireless 2200BG> mem 0xc0214000-0xc0214fff irq 11 at device 
2.0 on pci2
wlan0: Ethernet address: 00:12:f0:ca:5c:85

I get this a lot, but don't know if it's relevant.  It seems
to appear during both good and bad connections:

iwi0: need multicast update callback

Here's 61db of S/N ratio, resulting in almost 50% packet loss:

$ wlanstats ; ping -c20 wap2
36       rx frame too short
5        rx from wrong bssid
374      rx discard 'cuz dup
5        rx discard 'cuz mcast echo
3        rx discard mgt frames
1347     rx beacon frames
4151     rx element unknown
42       rx frame chan mismatch
7        rx disassociation
7        beacon miss events handled
6        active scans started
1446     rx management frames
2        tx failed 'cuz vap not in RUN state
28752    total data frames received
8679     unicast data frames received
20073    multicast data frames received
12186    total data frames transmit
12186    unicast data frames sent
54M      current transmit rate
61       current rssi
-95      current noise floor (dBm)
-34      current signal (dBm)
PING wap2 ( 56 data bytes
64 bytes from icmp_seq=0 ttl=64 time=20.726 ms
64 bytes from icmp_seq=1 ttl=64 time=0.974 ms
64 bytes from icmp_seq=2 ttl=64 time=1.278 ms
64 bytes from icmp_seq=3 ttl=64 time=1.942 ms
64 bytes from icmp_seq=4 ttl=64 time=1.008 ms
64 bytes from icmp_seq=8 ttl=64 time=0.921 ms
64 bytes from icmp_seq=10 ttl=64 time=1.755 ms
64 bytes from icmp_seq=11 ttl=64 time=0.934 ms
64 bytes from icmp_seq=13 ttl=64 time=2.803 ms
64 bytes from icmp_seq=16 ttl=64 time=1.698 ms
64 bytes from icmp_seq=18 ttl=64 time=2.382 ms

--- wap2 ping statistics ---
20 packets transmitted, 11 packets received, 45.0% packet loss
round-trip min/avg/max/stddev = 0.921/3.311/20.726/5.540 ms

To my knowledge the OS is using the latest 3.1 firmware for the

$ cd /usr/src/sys/contrib/dev/iwi
$ grep ^FW Makefile; md5 *
MD5 (LICENSE) = 11963afae1fb1117b86fde8187152b9a
MD5 (Makefile) = 2e4c774520e878e5cf8f3be7373fec02
MD5 (ipw2200-bss.fw.uu) = 7c15a60e1ccf28c332d3d795af99012b
MD5 (ipw2200-ibss.fw.uu) = b529089d6eee6c12a918f361ee2c8347
MD5 (ipw2200-sniffer.fw.uu) = 9e6c7a76cb528cb1d9f1996189d9c699

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