WLANCTL(8) BSD System Manager's Manual WLANCTL(8)NAMEwlanctl — examine IEEE 802.11 wireless LAN client/peer table
SYNOPSISwlanctl [-p] interface [...]
wlanctl [-p] -a
DESCRIPTION
Use the wlanctl utility to print node tables from IEEE 802.11 interfaces.
Use the -a flag to print the nodes for all interfaces, or list one or
more 802.11 interfaces to select their tables for examination. The -p
flag causes only nodes that do not have encryption enabled to be printed.
For example, to examine the node tables for atw0, use:
wlanctl atw0
wlanctl may print this node table, for example:
atw0: mac 00:02:6f:20:f6:2e bss 02:02:6f:20:f6:2e
node flags 0001<bss>
ess <netbsd>
chan 11 freq 2462MHz flags 00a0<cck,2.4GHz>
capabilities 0022<ibss,short preamble>
beacon-interval 100 TU tsft 18425852102545544165 us
rates [1.0] 2.0 5.5 11.0
assoc-id 0 assoc-failed 0 inactivity 0s
rssi 161 txseq 10 rxseq 1420
atw0: mac 00:02:2d:2e:3c:f4 bss 02:02:6f:20:f6:2e
node flags 0000
ess <netbsd>
chan 11 freq 2462MHz flags 00a0<cck,2.4GHz>
capabilities 0002<ibss>
beacon-interval 100 TU tsft 18425852105450086784 us
rates [1.0] 2.0 5.5 11.0
assoc-id 0 assoc-failed 0 inactivity 0s
rssi 159 txseq 2 rxseq 551
atw0: mac 00:02:6f:20:f6:2e bss 02:02:6f:20:f6:2e
node flags 0000
ess <netbsd>
chan 11 freq 2462MHz flags 00a0<cck,2.4GHz>
capabilities 0022<ibss,short preamble>
beacon-interval 100 TU tsft 18425852102558548069 us
rates [1.0] 2.0 5.5 6.0 9.0 11.0 12.0 18.0 24.0 36.0 48.0 54.0
assoc-id 0 assoc-failed 0 inactivity 145s
rssi 163 txseq 9 rxseq 2563
This example is taken from a network consisting of three stations running
in ad hoc mode. The key for interpreting the node print-outs follows:
mac In the example node table, the first network node has MAC
number 00:02:6f:20:f6:2e.
bss The first node belongs to the 802.11 network identified by
Basic Service Set Identifier (BSSID) 02:02:6f:20:f6:2e.
node flags Only three node flags, “bss”, “sta”, and “scan”, are
presently defined. The first node is distinguished from
the rest by its node flags: flag “bss” indicates that the
node represents the 802.11 network that the interface has
joined or created. The MAC number for the node is the same
as the MAC number for the interface.
ess the name of the (Extended) Service Set we have joined.
This is the same as the network name set by ifconfig(8)
with the “ssid” option.
chan wlanctl prints the channel number, the center frequency in
megahertz, and the channel flags. The channel flags indi‐
cate the frequency band (“2.4GHz” or “5GHz”), modulation
(“cck”, “gfsk”, “ofdm”, “turbo”, and “dynamic cck-ofdm”),
and operation constraints (“passive scan”). Common combi‐
nations of band and modulation are these:
Band Modulation Description
2.4GHz cck 11Mb/s DSSS 802.11b
2.4GHz gfsk 1-2Mb/s FHSS 802.11
2.4GHz ofdm 54Mb/s 802.11g
2.4GHz dynamic cck-ofdm mixed 802.11b/g network
5GHz ofdm 54Mb/s 802.11a
5GHz turbo 108Mb/s 802.11a
capabilities ad hoc-mode and AP-mode 802.11 stations advertise their
capabilities in 802.11 Beacons and Probe Responses.
wlanctl understands these capability flags:
Flag Description
ess infrastructure (access point) network
ibss ad hoc network (no access point)
cf pollable TBD
request cf poll TBD
privacy WEP encryption
short preamble reduce 802.11b overhead
pbcc 22Mbps ``802.11b+''
channel agility change channel for licensed services
short slot-time TBD
rsn TBD Real Soon Now
dsss-ofdm TBD
beacon-interval
In the example, beacons are sent once every 100 Time Units.
A Time Unit (TU) is 1024 microseconds (a “kilo-microsecond”
or “kus”). Thus 100 TU is about one tenth of a second.
tsft 802.11 stations keep a Time Synchronization Function Timer
(TSFT) which counts up in microseconds. Ad hoc-mode sta‐
tions synchronize time with their peers. Infrastructure-
mode stations synchronize time with their access point.
Power-saving stations wake and sleep at intervals measured
by the TSF Timer. The TSF Timer has a role in the coales‐
cence of 802.11 ad hoc networks (“IBSS merges”).
rates 802.11 stations indicate the bit-rates they support, in
units of 100kb/s in 802.11 Beacons, Probe Responses, and
Association Requests. wlanctl prints a station's supported
bit-rates in 1Mb/s units. A station's basic rates are
flagged by an asterisk (‘*’). The last bit-rate at which a
packet was sent to the station is enclosed by square brack‐
ets.
assoc-id In an infrastructure network, the access point assigns each
client an Association Identifier which is used to indicate
traffic for power-saving stations.
assoc-failed The number of times the station tried and failed to asso‐
ciate with its access point. Only
inactivity Seconds elapsed since a packet was last received from the
station. When this value reaches net.link.ieee80211.maxin‐
act, the station is eligible to be purged from the node ta‐
ble. See sysctl(8).
rssi Unitless Received Signal Strength Indication (RSSI).
Higher numbers indicate stronger signals. Zero is the low‐
est possible RSSI. On a hostap- or adhoc-mode interface,
the node with node flag “bss” set uses rssi to indicate the
signal strength for the last packet received from a station
that does not belong to the network. On an infrastructure-
mode station, the node with node flag “bss” set indicates
the strength of packets from the access point.
txseq The next 802.11 packet sent to this station will carry this
transmit sequence number. The 802.11 MAC uses the transmit
sequence number to detect duplicate packets.
rxseq The last packet received from this station carried this
transmit sequence number.
SEE ALSOsysctl(8)HISTORYwlanctl first appeared in NetBSD 3.0.
AUTHORS
David Young ⟨dyoung@NetBSD.org⟩
BSD July 15, 2004 BSD
