Re: Modification of power

I had sent this out a few days ago. Heard nothing. Anyone has any 
inputs/pointers ?

Thanks


On Tue, 3 Jan 2006, Vikram KAUL wrote:
vkaul>
vkaul>I am using a Linksys WCF12 Wireless CompactFlash Card on the PCMCIA slot
vkaul>using the wlan-ng driver.
vkaul>
vkaul>Using the
vkaul>wlanctl-ng wlan0 dot11req_mibget mibattribute-dot11CurrentTxPowerLevel
vkaul>I can get the current level which is set to a default of 18 (and reflected
vkaul>as 18 dBm, if I do iwconfig)
vkaul>
vkaul>Now, the 802.11 mib states that:
vkaul>
vkaul>dot11CurrentTxPowerLevel OBJECT-TYPE
vkaul>        SYNTAX INTEGER (1..8)
vkaul>        MAX-ACCESS read-write
vkaul>        STATUS current
vkaul>        DESCRIPTION
vkaul>            "The TxPowerLevel N currently being used to transmit data.
vkaul>            Some PHYs also use this value to determine the receiver
vkaul>            sensitivity requirements for CCA."
vkaul>    ::= { dot11PhyTxPowerEntry 10 }
vkaul>
vkaul>
vkaul>which points to the 8 levels, where I am providing the 2nd one for
vkaul>reference:
vkaul>
vkaul>dot11TxPowerLevel1 OBJECT-TYPE
vkaul>        SYNTAX INTEGER (0..10000)
vkaul>        MAX-ACCESS read-only
vkaul>        STATUS current
vkaul>        DESCRIPTION
vkaul>            "The transmit output power for LEVEL1 in mW.
vkaul>            This is also the default power level."
vkaul>    ::= { dot11PhyTxPowerEntry 2 }
vkaul>
vkaul>
vkaul>Now, these levels are not readable. If one attempts to do so, the result
vkaul>code is "not_supported"
vkaul>
vkaul>My questions are:
vkaul>
vkaul>1. Why is it that the default value of the dot11CurrentTxPowerLevel is not
vkaul>   within the range (1-8)
vkaul>
vkaul>2. Why can I set it to an non-negative integer, and this gets reflected
vkaul>   when I run 'iwconfig wlan0' to check whether the setting has held. I
vkaul>   can use absurd values like 3000 in
vkaul>
vkaul>wlanctl-ng wkan0 dot11req_mibset
vkaul>mibattribute=dot11CurrentTxPowerLevel=3000
vkaul>
vkaul>   and it reflects that in iwconfig. Why is this being allowed at all ?
vkaul>   What does it mean ?
vkaul>
vkaul>3. Why is it that this variable, when configured between 1 and 8 (the
vkaul>   correct range), produces no change in the 'real' transmitted power
vkaul>   as measured by another laptop using iwspy ? Have the levels been set
vkaul>   to the same value ?
vkaul>
vkaul>4. In summary, can wlan-ng be used to control the transmit power of the
vkaul>   card at all ? Has anyone accomplished it at all ?
vkaul>
vkaul>Thanks in advance
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vkaul>