Some doubt about Wireless Zero Configuration

Discussion in 'Windows Vista Drivers' started by tianjun, Jan 24, 2005.

  1. tianjun

    tianjun Guest

    Hi All,
    (1)why and when WZC set invalid SSID as OID_802_11_SSID?
    (2)If WZC set a SSID ,the Driver must called NdisMIndicateStatus to indicate
    the status of Connected,right?
    (3)if the driver indicate the status of Connected without WZC set a SSID to
    associate with ,then WZC will make the driver to disassociate ,right?
    Can somebody tell me the truth?TKS!

    Sincerely yours,
    tianjun, Jan 24, 2005
    1. Advertisements

  2. tianjun

    Susaant Guest

    WZC sets a invalid OID_802_11_SSID first just so that you would
    disconnect with any assciations that must have been made so far. (For
    the cases where an adapter acts as in your (3) question). Just
    disassociate with existing associations and fail the request.
    'ONLY IF' the association to that BSSID is sucessful then you have to
    indicate status as connected. (If you are already associated to a AP
    and you get a different SSID set then first diconnect and indicate
    disconnect status and then attempt to connect to the new SSID and
    indicate status depending on result).
    Should not do it. Not sure how NDIS will treat this but as I said in
    above cases when NDIS tried to set first (invalid) SSID then disconnect
    to existing AP yourself and then indicate status failure to this SSID.

    DDK is pretty clear on this topic just re-read it and things should
    clear up.
    Susaant, Jan 24, 2005
    1. Advertisements

  3. Additionally :

    I'm not sure that it's the case because CU ( any ) use
    OID_802_11_DISASSOCIATE for that,
    maybe CU receive list of APs choose one ( due to signal strenght or any
    other algorithm ) desided to set one but
    on the time the set come to driver , that AP gone ( like station go out of
    range or something like that ) because as you
    remember WZC ( e.g. ) as the list once per minute ( by default )

    NDIS ( at least not native ) don't care about that , but 802.11 itself stand
    driver of STA have dissconnect on start and wait for connect from utility

    Arkady Frenkel, Jan 24, 2005
  4. tianjun

    Susaant Guest

    The reason that NDIS does not use OID_802_11_DISASSOCIATE is because
    DDK says when OID_802_11_DISASSOCIATE is received in addition to
    disassociating from the current service set the NIC should also turn
    off the radio. But, At this stage NDIS does not want the NIC to turn
    off its radio, but rather 'dissconnect on start and wait for connect
    from utility' as you said 802.11 wants.
    Susaant, Jan 24, 2005
  5. tianjun

    Pavel A. Guest

    No idea why the radio should be on when the adapter is not associated and
    not going to associate. Maybe the intention is to keep scanning and see
    There were rumors that MS is considering a new OID to explicitly turn radio
    on and off. If driver would implement this OID , OID_802_11_DISASSOCIATE will
    not turn radio off. Don't know why anything like this had not been done yet;
    sometimes their logic is out of reach of mere mortals.

    Also, it is not clear how to tell a "good " SSID from a "garbage" one. SSID
    is just a binary array of 32 bytes and, in theory, can take any value. We've
    noticed that "garbage" SSID is always 32 bytes long and can contain non
    printable characters.

    Pavel A., Jan 24, 2005
  6. (2)If WZC set a SSID ,the Driver must called NdisMIndicateStatus to indicate
    It does so after the Wi-Fi level stuff is OK and it is capable of
    transmit/receive Ethernet frames.
    From what I know on WinCE 4.2, the first WZC's step on device awaken is - query
    the current SSID. Maybe this will help.
    Maxim S. Shatskih, Jan 24, 2005
  7. tianjun

    RonM Guest

    Ahh, but some people missed the small print. OID_802_11_DISASSOCIATE is optional.
    So not all drivers are guaranteed to have that OID. If you watch WHQL it uses ""RADIO_OFF"
    as an invalid SSID to force a disassociate. It does not depend on OID_802_11_DISASSOCIATE.
    Yes WZC uses unprintable SSID to force disassociate. It the SSID does not match anything in
    your scan list.... you are done. Indicate disconnected, wait for further orders :)
    RonM, Jan 25, 2005
  8. tianjun

    RonM Guest

    Make that "optional for NDIS 5.0" because who wants to not be compatible with Win2000!
    RonM, Jan 25, 2005
  9. tianjun

    Pavel A. Guest

    No, OID_802_11_DISASSOCIATE is not optional.
    Per the current DDK docum, it is mandatory for XP and WPA.
    ( anybody cares about win2000? )

    Pavel A., Jan 25, 2005
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.