iwconfig.8

采用嵌入式开发的wireless无线模组的应用开发工具

.\" Jean II - HPLB - 1996 => HPL - 2004
.\" iwconfig.8
.\"
.TH IWCONFIG 8 "22 June 2004" "wireless-tools" "Linux Programmer's Manual"
.\"
.\" NAME part
.\"
.SH NAME
iwconfig \- configure a wireless network interface
.\"
.\" SYNOPSIS part
.\"
.SH SYNOPSIS
.BI "iwconfig [" interface ]
.br
.BI "iwconfig " interface " [essid " X "] [nwid " N "] [freq " F "] [channel " C ]
.br
.BI "                   [sens " S "] [mode " M "] [ap " A "] [nick " NN ]
.br
.BI "                   [rate " R "] [rts " RT "] [frag " FT "] [txpower " T ]
.br
.BI "                   [enc " E "] [key " K "] [power " P "] [retry " R ]
.br
.BI "                   [commit]
.br
.BI "iwconfig --help"
.br
.BI "iwconfig --version"
.\"
.\" DESCRIPTION part
.\"
.SH DESCRIPTION
.B Iwconfig
is similar to
.IR ifconfig (8),
but is dedicated to the wireless interfaces. It is used to set the
parameters of the network interface which are specific to the wireless
operation (for example : the frequency).
.B Iwconfig
may also be used to display those parameters, and the wireless
statistics (extracted from
.IR /proc/net/wireless ).
.PP
All these parameters and statistics are device dependent. Each driver
will provide only some of them depending on hardware support, and the
range of values may change. Please refer to the man page of each
device for details.
.\"
.\" PARAMETER part
.\"
.SH PARAMETERS
.TP
.B essid
Set the ESSID (or Network Name - in some products it may also be
called Domain ID). The ESSID is used to identify cells which are part
of the same virtual network.
.br
As opposed to the AP Address or NWID which define a single cell, the
ESSID defines a group of cells connected via repeaters or
infrastructure, where the user may roam transparently.
.br
With some cards, you may disable the ESSID checking (ESSID
promiscuous) with
.IR off " or " any " (and " on
to reenable it).
.br
.B Examples :
.br
.I "	iwconfig eth0 essid any"
.br
.I "	iwconfig eth0 essid ""My Network""
.TP
.BR nwid / domain
Set the Network ID (in some products it may also be called Domain
ID). As all adjacent wireless networks share the same medium, this
parameter is used to differenciate them (create logical colocated
networks) and identify nodes belonging to the same cell.
.br
This parameter is only used for pre-802.11 hardware, the 802.11
protocol uses the ESSID and AP Address for this function.
.br
With some cards, you may disable the Network ID checking (NWID
promiscuous) with
.IR off " (and " on
to reenable it).
.br
.B Examples :
.br
.I "	iwconfig eth0 nwid AB34
.br
.I "	iwconfig eth0 nwid off"
.TP
.BR freq / channel
Set the operating frequency or channel in the device. A value below
1000 indicates a channel number, a value greater than 1000 is a
frequency in Hz. You may append the suffix k, M or G to the value (for
example, "2.46G" for 2.46 GHz frequency), or add enough '0'.
.br
Channels are usually numbered starting at 1, and you may use
.IR iwlist (8)
to get the total number of channels, list the available frequencies,
and display the current frequency as a channel. Depending on
regulations, some frequencies/channels may not be available.
.br
.B Examples :
.br
.I "	iwconfig eth0 freq 2422000000"
.br
.I "	iwconfig eth0 freq 2.422G"
.br
.I "	iwconfig eth0 channel 3"
.TP
.B sens
Set the sensitivity threshold. This is the lowest signal level for
which the hardware attempt packet reception, signals weaker than this
are ignored. This is used to avoid receiving background noise, so you
should set it according to the average noise level. Positive values
are assumed to be the raw value used by the hardware or a percentage,
negative values are assumed to be dBm.
.br
With some hardware, this parameter also controls the defer threshold
(lowest signal level for which the hardware consider the channel busy)
and the handover threshold (signal level where the hardware start
looking for a new access point).
.br
.B Example :
.br
.I "	iwconfig eth0 sens -80"
.TP
.B mode
Set the operating mode of the device, which depends on the network
topology. The mode can be
.I Ad-Hoc
(network composed of only one cell and without Access Point),
.I Managed
(node connects to a network composed of many Access Points, with roaming),
.I Master
(the node is the synchronisation master or acts as an Access Point),
.I Repeater
(the node forwards packets between other wireless nodes),
.I Secondary
(the node acts as a backup master/repeater),
.I Monitor
(the node is not associated with any cell and passively monitor all
packets on the frequency) or
.IR Auto .
.br
.B Example :
.br
.I "	iwconfig eth0 mode Managed"
.br
.I "	iwconfig eth0 mode Ad-Hoc"
.TP
.B ap
Force the card to register to the Access Point given by the address,
if it is possible. When the quality of the connection goes too low,
the driver may revert back to automatic mode (the card selects the
best Access Point in range).
.br
You may also use
.I off
to re-enable automatic mode without changing the current Access Point,
or you may use
.I any
or
.I auto
to force the card to reassociate with the currently best Access Point.
.br
.B Example :
.br
.I "	iwconfig eth0 ap 00:60:1D:01:23:45"
.br
.I "	iwconfig eth0 ap any"
.br
.I "	iwconfig eth0 ap off"
.TP
.BR nick [name]
Set the nickname, or the station name. Some 802.11 products do define
it, but this is not used as far as the protocols (MAC, IP, TCP) are
concerned and completely useless as far as configuration goes. Only
some diagnostic tools may use it.
.br
.B Example :
.br
.I "	iwconfig eth0 nickname ""My Linux Node""
.TP
.BR rate / bit [rate]
For cards supporting multiple bit rates, set the bit-rate in b/s. The
bit-rate is the speed at which bits are transmitted over the medium,
the user speed of the link is lower due to medium sharing and
various overhead.
.br
You may append the suffix k, M or G to the value (decimal multiplier :
10^3, 10^6 and 10^9 b/s), or add enough '0'. Values below 1000 are
card specific, usually an index in the bit-rate list. Use
.I auto
to select automatic bit-rate mode (fallback to lower rate on noisy
channels), which is the default for most cards, and
.I fixed
to revert back to fixed setting. If you specify a bit-rate value and append
.IR auto ,
the driver will use all bit-rates lower and equal than this value.
.br
.B Examples :
.br
.I "	iwconfig eth0 rate 11M"
.br
.I "	iwconfig eth0 rate auto"
.br
.I "	iwconfig eth0 rate 5.5M auto"
.TP
.BR rts [_threshold]
RTS/CTS adds a handshake before each packet transmission to make sure
that the channel is clear. This adds overhead, but increases
performance in case of hidden nodes or a large number of active
nodes. This parameter sets the size of the smallest packet for which
the node sends RTS ; a value equal to the maximum packet size disable
the mechanism. You may also set this parameter to
.IR auto ", " fixed " or " off .
.br
.B Examples :
.br
.I "	iwconfig eth0 rts 250"
.br
.I "	iwconfig eth0 rts off"
.TP
.BR frag [mentation_threshold]
Fragmentation allows to split an IP packet in a burst of smaller
fragments transmitted on the medium. In most cases this adds overhead,
but in a very noisy environment this reduces the error penalty and
allow packets to get through interference bursts. This parameter sets
the maximum fragment size ; a value equal to the maximum packet size
disable the mechanism. You may also set this parameter to
.IR auto ", " fixed " or " off .
.br
.B Examples :
.br
.I "	iwconfig eth0 frag 512"
.br
.I "	iwconfig eth0 frag off"
.TP
.BR key / enc [ryption]
Used to manipulate encryption or scrambling keys and security mode.
.br
To set the current encryption key, just enter the key in hex digits as
.IR XXXX-XXXX-XXXX-XXXX " or " XXXXXXXX .
To set a key other than the current key, prepend or append
.I [index]
to the key itself (this won't change which is the active key). You can
also enter the key as an ASCII string by using the
.I s:
prefix. Passphrase is currently not supported.
.br
To change which key is the currently active key, just enter
.I [index]
(without entering any key value).
.br
.IR off " and " on
disable and reenable encryption.
.br
The security mode may be
.I open
or