question about standard (Jim Geier help me)

[delxu]

I am just reading the 802.11 standard, and one things puzzled me.

There are ToDS and FromDS flags in the frame control field of every data frame of 802.11, which means
"The ToDS field is set to 1 in data type frames destined for the DS...."
"The From DS field ... is set to 1 in data type frames exiting the DS"

But how does the STA know whether the current destination is located in the same BSS or DS or another BSS, so how does it know the setting of ToDS and FromDS field in every data frame???

[Sundar]

The 802.11 standard defines two types of networks - IBSS and InfraBSS.

The ToDS and FromDS bits are used only in the InfraBSS mode of operation. And in that mode, the STA doesn't require to know the where abouts of the receiving station. It can simply set the ToDS bit and transmit the packet. It is required that the STA is associated with an AP before doing any data transfer.

Now the identification of the receiving station will be done by the AP and the packet will be retransmitted with new values for ToDS and FromDS bits.
Hope this helps

-
Sundar

[delxu]

Thanks.

I am using a SMC2632W 802.11b WLAN adapter, which is not supported by SnifferPro Wireless or NetStumbler. Otherwise, I can use the Protocol Analyzer to grab some 802.11 frame and have a look of the fields and flags in it.

Are there any tools support SMC?