OID_802_11_BSSID in ad-hoc mode

  • Thread starter Thread starter Stefan
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Stefan

I would like to use the OID_802_11_BSSID in ad-hoc mode controlling my
WLAN adapter to chose a particular WLAN network. I have the situation
that I have more than one networks having the same SSID. They
distinguish themself only via the MAC/BSSID address. Anything shall be
running under Windows XP SP1. I've checked out several drivers under
XP so far. Unfortunatly, only the Intel 2100B driver does accept this
OID (set & querry) at all - however, it does not actually change the
BSSID. For me it seems, as if it only replies by S_OK without changing
the BSSID.
Any other driver (from Intersil, or whomever...) did not work either.
Most of them even reply by E_FAIL on either SET or QUERRY of
OID_802_11_BSSID.

Has anyone of you made a similar experience?

Does the OID_802_11_BSSID will be tested in XP logo certification at
all for ad-hoc mode?
 
Stefan said:
Does the OID_802_11_BSSID will be tested in XP logo certification at
all for ad-hoc mode?
Click to expand...

No. Ndistest 4.3.44 tests IBSS connection only by SSID.
Moreover, the latest public Microsoft 802.11 Network Adapter Design document
does not specify what should do setting OID_802_11_BSSID in IBSS mode.
It specifies only that getting this OID will return IBSS MAC address.

Regards,
--PA
 
Have you set the SSID to be an empty SSID before setting the BSSID?

Thomas F. Divine
 
Stefan said:
I have the situation
that I have more than one networks having the same SSID. They
distinguish themself only via the MAC/BSSID address.
Click to expand...

BSSID of the Ad-Hoc network is a random number and may (and will) change
every time network is created. Also, if you have 2 Ad-Hoc networks with the
same SSID running at the same time and overlapping, you dont' have 2
networks - this is one big Ad-Hoc network. In Ad-Hoc, there's no
association.
 
Originally, I havnt set the SSID to be an empty SSID before setting
the BSSID. However, I expliciltly tried out this hint, unfortunatly,
without influencing my drivers behaviour at all. It still does open
its own SSID with a seperate BSSID. So, I believe, that wont help.
Moreover, it does not really sound very promising to do so...
Anyway, thanks a lot for your opinion.
 
I agree with your opinion that in ad-hoc mode the BSSID is a random
number. However, I strongly disagree with your opinion about the 2
ad-hoc networks having the same SSID and different BSSID to be seen as
one BIG ad-hoc network. My tests, clearly show that there are 2
distinct ad-hoc networks which cannot be seen as one single network. I
have debugged the secanrio so far, that I am sure that the SSID on
both networks are the same, the BSSID is differnt. I am also sure that
both networks are using the same channel coding (in my situation DSSS
which is used for 802.11b) as well as running on the same channel
(channel 11 in my case). Each network only has one PC in it, and it is
not possible to ping from one machine to the other, and vice versa.
If your theory would be true that it is one big network, then I expect
that the ping would work.
 
Stefan said:
I agree with your opinion that in ad-hoc mode the BSSID is a random
number. However, I strongly disagree with your opinion about the 2
ad-hoc networks having the same SSID and different BSSID to be seen as
one BIG ad-hoc network. My tests, clearly show that there are 2
distinct ad-hoc networks which cannot be seen as one single network.
Click to expand...

Let us assume you've got a node between these 2 networks which can
communicate with both networks at the same time (by using high-gain antennas
if needed). MLME-START request doesn't specify BSSID of the network to join,
but rather SSID. Upon receiving MLME-START request station has no way to
prefer one network vs. another. (I assume basic rates and capabilities
parameters allow the station to join both networks). Since this station has
no way to distinguish two networks, these 2 networks are not really
separate. Of course, term separate is somewhat vague, but I hope you get my
point.

Of course you can physically separate them, but than you won't have any need
to set BSSID, since your NIC is able to communicate to only one network at
any given time.
 
All,
You need to get ahold of the 802.11 spec and read about IBSS Coalescing.

Ad-hoc stations will 'adopt' the BSSID of the latest station to transmit a
Beacon if the SSID is the Same.

So in your scenerio where there are many IBSS stations in proximity, they
will all end up with the same BSSID after a very short period of time and
participate in the same Ad-hoc network.
 
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