man iwconfig(무선 네트워크 인터페이스 환경 설정 명령어)

NAME

       iwconfig - 무선 네트워크 인터페이스 환경 설정

DESCRIPTION

      Iwconfig는 ifconfig와 유사하지만, 무선 인터페이스를 위한 것입니다.

      그것은 특수한 무선 동작(예를 들면:주파수)와 같은 네트워크 인터페이스 변수 설정에 사용됩니다.

      Iwconfig는 이들 변수와 무선통계(/proc/net/wireless로부터 추출된)을 보여주는데 사용될 수 있습니다.

      

      모든 변수들과 통계는 장치 독립적이고, 각각의 드라이버는 하드웨어의 지원에 따라 그들의 일부만을 공급할 것입니다. 그리고 값의 범위는 변경될지도 모릅니다. 자세한 것은 각각의 장치의 man page를 참조.

PARAMETERS

       essid ESSID를 설정합니다. (몇몇의 제품에서는 Domain ID로 불리워진다.) 

       단일 cell로 정의되는 AP Address 또는 NWID와 상반되는 것으로서, ESSID는 그룹의 개념(Cells)을 갖습니다.

       몇몇의 카드에서 any, off를 사용하면 ESSID를 사용하여 사용하지 않게 할 수 있습니다.

              Examples :

                   iwconfig eth0 essid any

                   iwconfig eth0 essid "My Network"

                   iwconfig eth0 essid -- "ANY"

       nwid   Network ID를 설정합니다. 

              pre-802.11에 대해서만 사용하고, 802.11 프로토콜에서는 ESSID와 AP address를 사용합니다.

             몇몇의 카드에서 NWID를 설정하는 것을 통해 On, Off를 설정가능합니다.

              Examples :

                   iwconfig eth0 nwid AB34

                   iwconfig eth0 nwid off

       nick[name] 별명을 설정합니다.

              Example :

                   iwconfig eth0 nickname "My Linux Node"

       mode :  네트워크 topology에 따른 장치의 동작 모드를 설정합니다.    

             설정 가능한 모드는 다음과 같습니다.

              Ad-Hoc      :  network composed of only one cell and without Access Point

              Managed   :  node connects to  a network  composed  of  many Access Points, with roaming

              Master       :  the node is the synchronisation master or  acts  as  an  Access Point

              Repeater    : the node forwards packets between other wireless  nodes

              Secondary : the  node  acts  as  a  backup   master/repeater

              Monitor       : the node is not associated with any cell and passively monitor all packets on the frequency

              Example :

                   iwconfig eth0 mode Managed

                   iwconfig eth0 mode Ad-Hoc

       freq/channel : 장치의 채널 또는 동작 주파수를 설정합니다.

              1000이하는 채널값으로 사용하고 1000보다 큰 값은 주파수로 사용됨(단위:HZ)

              채널은 보통 1부터 시작되고, 총 채널수를 확인하기 위해 'iwlist'를 사용해도 됩니다.

              Examples :

                   iwconfig eth0 freq 2422000000

                   iwconfig eth0 freq 2.422G

                   iwconfig eth0 channel 3

                   iwconfig eth0 channel auto

       ap   주소에 의해 Access Point에 저장하도록 합니다.

              무선 scanning에 의해 레포트된 Access point는 MAC address와 다를 수 있습니다.

              무선 연결이 PTP, ad-hoc에 따라 주소가 다르게 설정됩니다.

              Example :

                   iwconfig eth0 ap 00:60:1D:01:23:45

                   iwconfig eth0 ap any

                   iwconfig eth0 ap off

       rate/bit[rate]

              bit-rate를 설정합니다. 

              bit-rate를 자동(auto)모드로 선택이 가능합니다. 

              Examples :

                   iwconfig eth0 rate 11M

                   iwconfig eth0 rate auto

                   iwconfig eth0 rate 5.5M auto

       txpower

              transmit power(단위dBm)을 설정합니다. 

              W는 Watt이면, P(dbm) = 30 + 10.log(W)가 됩니다.

              Examples :

                   iwconfig eth0 txpower 15

                   iwconfig eth0 txpower 30mW

                   iwconfig eth0 txpower auto

                   iwconfig eth0 txpower off

아직 영어가 조금 부족한 관계로 자세한 사항은 영문 man 페이지를 참조해 주세요.
====================================================================

# man iwconfig

NAME

       iwconfig - configure a wireless network interface

SYNOPSIS

       iwconfig [interface]

       iwconfig interface [essid X] [nwid N] [mode M] [freq F]

                          [channel C][sens S ][ap A ][nick NN ]

                          [rate R] [rts RT] [frag FT] [txpower T]

                          [enc E] [key K] [power P] [retry R]

                          [modu M] [commit]

       iwconfig --help

       iwconfig --version

DESCRIPTION

       Iwconfig  is  similar  to 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 fre-

       quency).  Iwconfig may also be used to display  those  parameters,  and

       the wireless statistics (extracted from /proc/net/wireless).

       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.

PARAMETERS

       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.

              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.

              With some cards, you  may  disable  the  ESSID  checking  (ESSID

              promiscuous) with off or any (and on to reenable it).

              If  the  ESSID  of  your  network is one of the special keywords

              (off, on or any), you should use -- to escape it.

              Examples :

                   iwconfig eth0 essid any

                   iwconfig eth0 essid "My Network"

                   iwconfig eth0 essid -- "ANY"

       nwid   Set the Network ID. As all adjacent wireless networks share  the

              same  medium, this parameter is used to differentiate them (cre-

              ate logical colocated networks) and identify nodes belonging  to

              the same cell.

              This  parameter is only used for pre-802.11 hardware, the 802.11

              protocol uses the ESSID and AP Address for this function.

              With some cards, you may disable the Network ID  checking  (NWID

              promiscuous) with off (and on to reenable it).

              Examples :

                   iwconfig eth0 nwid AB34

                   iwconfig eth0 nwid off

       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 configu-

              ration goes. Only some wireless diagnostic tools may use it.

              Example :

                   iwconfig eth0 nickname "My Linux Node"

       mode   Set the operating mode of the device, which depends on the  net-

              work  topology. The mode can be Ad-Hoc (network composed of only

              one cell and without Access Point), Managed (node connects to  a

              network  composed  of  many Access Points, with roaming), Master

              (the node is the synchronisation master or  acts  as  an  Access

              Point),  Repeater (the node forwards packets between other wire-

              less  nodes),  Secondary  (the  node  acts  as  a  backup   mas-

              ter/repeater), Monitor (the node is not associated with any cell

              and passively monitor all packets on the frequency) or Auto.

              Example :

                   iwconfig eth0 mode Managed

                   iwconfig eth0 mode Ad-Hoc

       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'.

              Channels are usually numbered starting at 1,  and  you  may  use

              iwlist(8)  to  get the total number of channels, list the avail-

              able frequencies, and display the current frequency as  a  chan-

              nel. Depending on regulations, some frequencies/channels may not

              be available.

              When using Managed mode, most often the  Access  Point  dictates

              the  channel  and  the driver may refuse the setting of the fre-

              quency. In Ad-Hoc mode, the frequency setting may only  be  used

              at  initial  cell  creation,  and may be ignored when joining an

              existing cell.

              You may also use off or auto to let the card pick  up  the  best

              channel (when supported).

              Examples :

                   iwconfig eth0 freq 2422000000

                   iwconfig eth0 freq 2.422G

                   iwconfig eth0 channel 3

                   iwconfig eth0 channel auto

       ap     Force  the  card  to  register  to the Access Point given by the

              address, if it is possible. This address is the cell identity of

              the Access Point, as reported by wireless scanning, which may be

              different from its network MAC address. If the wireless link  is

              point to point, set the address of the other end of the link. If

              the link is ad-hoc, set the cell identity of the ad-hoc network.

              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).

              You  may also use off to re-enable automatic mode without chang-

              ing the current Access Point, or you may  use  any  or  auto  to

              force  the  card  to  reassociate with the currently best Access

              Point.

              Example :

                   iwconfig eth0 ap 00:60:1D:01:23:45

                   iwconfig eth0 ap any

                   iwconfig eth0 ap off

       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.

              You may append the suffix k, M or G to the value (decimal multi-

              plier : 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 auto to select automatic bit-rate  mode  (fallback  to

              lower  rate  on  noisy  channels), which is the default for most

              cards, and fixed to revert back to fixed setting. If you specify

              a  bit-rate  value and append auto, the driver will use all bit-

              rates lower and equal than this value.

              Examples :

                   iwconfig eth0 rate 11M

                   iwconfig eth0 rate auto

                   iwconfig eth0 rate 5.5M auto

       txpower

              For cards supporting multiple transmit powers, sets the transmit

              power in dBm. If W is the power in Watt, the power in dBm is P =

              30 + 10.log(W).  If the value is postfixed by  mW,  it  will  be

              automatically converted to dBm.

              In  addition,  on and off enable and disable the radio, and auto

              and fixed enable and disable power control  (if  those  features

              are available).

              Examples :

                   iwconfig eth0 txpower 15

                   iwconfig eth0 txpower 30mW

                   iwconfig eth0 txpower auto

                   iwconfig eth0 txpower off

       sens   Set  the sensitivity threshold. This define how sensitive is the

              card to poor operating conditions  (low  signal,  interference).

              Positive  values  are  assumed  to  be the raw value used by the

              hardware or a percentage, negative values are assumed to be dBm.

              Depending  on  the  hardware  implementation, this parameter may

              control various functions.

              On modern cards, this parameter usually control handover/roaming

              threshold,  the  lowest  signal  level  for  which  the hardware

              remains associated with the current Access Point. When the  sig-

              nal  level goes below this threshold the card starts looking for

              a new/better Access Point. Some cards  may  use  the  number  of

              missed  beacons  to  trigger  this.  For  high density of Access

              Points, a higher threshold make sure the card is always  associ-

              ated with the best AP, for low density of APs, a lower threshold

              minimise the number of failed handoffs.

              On more ancient card this parameter usually controls  the  defer

              threshold,  the  lowest signal level for which the hardware con-

              siders the channel busy. Signal levels above this threshold make

              the  hardware  inhibits  its  own  transmission  whereas signals

              weaker than this are ignored and the hardware is free to  trans-

              mit.  This  is usually strongly linked to the receive threshold,

              the lowest signal level for which the hardware  attempts  packet

              reception.  Proper  setting of these thresholds prevent the card

              to waste time on background noise  while  still  receiving  weak

              transmissions.  Modern designs seems to control those thresholds

              automatically.

              Example :

                   iwconfig eth0 sens -80

                   iwconfig eth0 sens 2

       retry  Most cards have MAC retransmissions, and some allow to  set  the

              behaviour of the retry mechanism.

              To set the maximum number of retries, enter limit `value'.  This

              is an absolute value (without unit), and the default (when noth-

              ing  is  specified).   To set the maximum length of time the MAC

              should retry, enter lifetime `value'.  By defaults,  this  value

              in  in  seconds,  append  the suffix m or u to specify values in

              milliseconds or microseconds.

              You can also add the short, long, min and max modifiers. If  the

              card  supports  automatic  mode,  they  define the bounds of the

              limit or lifetime. Some  other  cards  define  different  values

              depending on packet size, for example in 802.11 min limit is the

              short retry limit (non RTS/CTS packets).

              Examples :

                   iwconfig eth0 retry 16

                   iwconfig eth0 retry lifetime 300m

                   iwconfig eth0 retry short 12

                   iwconfig eth0 retry min limit 8

       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 maxi-

              mum  packet  size  disables the mechanism. You may also set this

              parameter to auto, fixed or off.

              Examples :

                   iwconfig eth0 rts 250

                   iwconfig eth0 rts off

       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  which  is  always

              lower than the maximum packet size.

              This parameter may also control Frame Bursting available on some

              cards, the ability to send multiple IP  packets  together.  This

              mechanism  would  be enabled if the fragment size is larger than

              the maximum packet size.

              You may also set this parameter to auto, fixed or off.

              Examples :

                   iwconfig eth0 frag 512

                   iwconfig eth0 frag off

       key/enc[ryption]

              Used to manipulate encryption or scrambling  keys  and  security

              mode.

              To  set  the  current  encryption key, just enter the key in hex

              digits as XXXX-XXXX-XXXX-XXXX or XXXXXXXX.  To set a  key  other

              than  the  current  key,  prepend  or  append [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 s: prefix.

              Passphrase is currently not supported.

              To change which key is the  currently  active  key,  just  enter

              [index] (without entering any key value).

              off and on disable and reenable encryption.

              The  security  mode  may  be open or restricted, and its meaning

              depends on the card used. With  most  cards,  in  open  mode  no

              authentication  is  used  and  the  card  may  also  accept non-

              encrypted sessions, whereas in restricted  mode  only  encrypted

              sessions  are  accepted  and the card will use authentication if

              available.

              If you need to set multiple keys, or set a key  and  change  the

              active  key,  you need to use multiple key directives. Arguments

              can be put in any order, the last one will take precedence.

              Examples :

                   iwconfig eth0 key 0123-4567-89

                   iwconfig eth0 key [3] 0123-4567-89

                   iwconfig eth0 key s:password [2]

                   iwconfig eth0 key [2]

                   iwconfig eth0 key open

                   iwconfig eth0 key off

                   iwconfig eth0 key restricted [3] 0123456789

                   iwconfig eth0 key 01-23 key 45-67 [4] key [4]

       power  Used to manipulate power management scheme parameters and  mode.

              To  set  the  period between wake ups, enter period `value'.  To

              set the timeout  before  going  back  to  sleep,  enter  timeout

              `value'.  To set the generic level of power saving, enter saving

              `value'.  You can  also  add  the  min  and  max  modifiers.  By

              default,  those  values are in seconds, append the suffix m or u

              to specify values in milliseconds  or  microseconds.  Sometimes,

              those values are without units (number of beacon periods, dwell,

              percentage or similar).

              off and on disable and reenable power management.  Finally,  you

              may  set the power management mode to all (receive all packets),

              unicast (receive unicast packets  only,  discard  multicast  and

              broadcast)  and multicast (receive multicast and broadcast only,

              discard unicast packets).

              Examples :

                   iwconfig eth0 power period 2

                   iwconfig eth0 power 500m unicast

                   iwconfig eth0 power timeout 300u all

                   iwconfig eth0 power saving 3

                   iwconfig eth0 power off

                   iwconfig eth0 power min period 2 power max period 4

       modu[lation]

              Force the card to use a  specific  set  of  modulations.  Modern

              cards support various modulations, some which are standard, such

              as 802.11b or 802.11g, and some proprietary. This command  force

              the  card  to only use the specific set of modulations listed on

              the command line. This  can  be  used  to  fix  interoperability

              issues.

              The  list of available modulations depend on the card/driver and

              can be  displayed  using  iwlist  modulation.   Note  that  some

              card/driver  may  not  be  able to select each modulation listed

              independantly, some may come as a group. You may also  set  this

              parameter to auto let the card/driver do its best.

              Examples :

                   iwconfig eth0 modu 11g

                   iwconfig eth0 modu CCK OFDMa

                   iwconfig eth0 modu auto

       commit Some  cards  may  not apply changes done through Wireless Exten-

              sions immediately (they may wait to  aggregate  the  changes  or

              apply  it  only when the card is brought up via ifconfig).  This

              command (when available) forces the card to  apply  all  pending

              changes.

              This  is  normally  not needed, because the card will eventually

              apply the changes, but can be useful for debugging.

DISPLAY

       For each device which supports wireless extensions, iwconfig will  dis-

       play  the name of the MAC protocol used (name of device for proprietary

       protocols), the ESSID (Network Name), the NWID, the frequency (or chan-

       nel), the sensitivity, the mode of operation, the Access Point address,

       the bit-rate, the  RTS  threshold,  the  fragmentation  threshold,  the

       encryption  key  and the power management settings (depending on avail-

       ability).

       The parameters displayed have the same meaning and values as the param-

       eters  you  can  set,  please refer to the previous part for a detailed

       explanation of them.

       Some parameters are only displayed in short/abbreviated form  (such  as

       encryption). You may use iwlist(8) to get all the details.

       Some  parameters have two modes (such as bitrate). If the value is pre-

       fixed by `=', it means that the parameter is fixed and forced  to  that

       value, if it is prefixed by `:', the parameter is in automatic mode and

       the current value is shown (and may change).

       Access Point/Cell

              An address equal to 00:00:00:00:00:00 means that the card failed

              to  associate  with an Access Point (most likely a configuration

              issue). The Access Point parameter will be shown as Cell in  ad-

              hoc mode (for obvious reasons), but otherwise works the same.

       If  /proc/net/wireless  exists, iwconfig will also display its content.

       Note that those values will depend  on  the  driver  and  the  hardware

       specifics, so you need to refer to your driver documentation for proper

       interpretation of those values.

       Link quality

              Overall quality of the link. May be based on the level  of  con-

              tention  or  interference, the bit or frame error rate, how good

              the received signal is, some timing  synchronisation,  or  other

              hardware metric. This is an aggregate value, and depends totally

              on the driver and hardware.

       Signal level

              Received signal strength (RSSI - how strong the received  signal

              is).  May  be  arbitrary units or dBm, iwconfig uses driver meta

              information to interpret the raw value given by  /proc/net/wire-

              less  and  display the proper unit or maximum value (using 8 bit

              arithmetic). In Ad-Hoc mode,  this  may  be  undefined  and  you

              should use iwspy.

       Noise level

              Background  noise level (when no packet is transmitted). Similar

              comments as for Signal level.

       Rx invalid nwid

              Number of packets received with a different NWID or ESSID.  Used

              to  detect  configuration problems or adjacent network existence

              (on the same frequency).

       Rx invalid crypt

              Number of packets that the hardware was unable to decrypt.  This

              can be used to detect invalid encryption settings.

       Rx invalid frag

              Number  of  packets for which the hardware was not able to prop-

              erly re-assemble the link layer fragments (most likely  one  was

              missing).

       Tx excessive retries

              Number  of packets that the hardware failed to deliver. Most MAC

              protocols will retry the packet a number of times before  giving

              up.

       Invalid misc

              Other  packets  lost  in  relation with specific wireless opera-

              tions.

       Missed beacon

              Number of periodic beacons from the Cell or the Access Point  we

              have  missed.  Beacons are sent at regular intervals to maintain

              the cell coordination, failure to receive them usually indicates

              that the card is out of range.

AUTHOR

       Jean Tourrilhes - jt@hpl.hp.com

FILES

       /proc/net/wireless

SEE ALSO

       ifconfig(8), iwspy(8), iwlist(8), iwevent(8), iwpriv(8), wireless(7).

wireless-tools                   30 March 2006                     IWCONFIG(8)

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