wap54g "basic rates" setting, and prism hostap driver

Paul Fox pgf at brightstareng.com
Wed Mar 22 17:29:19 EST 2006

hi -- 

i don't know that anything is actually wrong, but i'm seeing something

i have a Linksys WAP54G (firmware 3.01), an NL-2511CD prism
pcmcia card (firmware 1.8.4), and hostap drivers (either 0.3.9 or
0.4.7, same results).  i'm using WPA, but don't know that that

the WAP54G has a setting for "Basic Rates", which can
have the values "ALL", "1-2 Mbps", and "Default".  if
i select either "1-2 Mbps" or "Default", all is well.  if
i select "ALL", i can no longer associate.  the Linksys
docs are as follows:

    Basic Rates.  This setting is not actually one rate of
    transmission but a series of rates that are advertised to the
    other wireless devices in your network, so they know at which
    rates the Access Point can transmit.  At the Default setting,
    the Access Point will advertise that it will automatically
    select the best rate for transmission.  Other options are
    1-2Mbps, for use with older wireless technology, and All,
    when you wish to have all rates advertised.  The Basic Data
    Rates are not the rates transmitted; the rates transmitted
    can be configured through the Transmission Rates setting on
    this screen.

why would the explicit advertisement of rates affect association?
is there a requirement that a client support all advertised rates?

the more i think about this, the more i think that my observed
behavior may be expected -- the AP is probably advertising
rates up through 54, and the card doesn't like them all, so it
doesn't associate.  or something like that.  but if that's the
case, i'm wondering what the possible use of this particular
negotiation is -- why wouldn't the AP and card just agree to the
mutually supported subset of rates, rather than an all-or-nothing

can anyone shed light?

 paul fox, pgf at brightstareng.com

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