User's Manual Part 1

A station in an ad hoc network constantly adapts itself to the current situation in the ad hoc
network as far as other stations capabilities are concerned. Updating of the supported transmit
data rates is done in the following way:
Only the basic rates change. Supported rates of a station never change. At all times the basic
rates advertised by stations in an ad hoc network should be the same, and should reflect the set
of basic rates supported by every station in this ad hoc network. Since basic rates is the actual
information used by a station to decide if it can join the ad hoc network then this is enough to
determine if a station can or cannot connect to this ad hoc network.
Mixed Mode
Mixed mode stations (802.11g and 802.11b) are able to join any ad hoc network they hear.
Joining an ad hoc network
● Join an 11b ad hoc network only – keep the supported rates and update the basic rates to
fit the ad hoc network you are joining. Protection (RTS/CTS or CTS-to-self) is on.
● Join an 11g ad hoc network only – keep the supported rates and up scale the basic rates
advertised in the beacons. Note that this is not good because the station ceases being a
“mixed mode” and become an 11g only station.
● Join an 11a and 11b ad hoc network only – keep the supported rates and update the basic
rates to fit the ad hoc network you are joining.
Initiating an ad hoc network
When initiating a mixed mode ad hoc network the default rates for mixed mode is: 1, 2, 5.5, 11, 6,
12, 18, 24, 36, 48 and 54 Mbps with rates 1, 2 as basic. When other stations join in, the basic
rates are down scaled if required. Protection is on when 11b station are joining.
11b only mode
Joining an ad hoc network
In this mode you can only join an ad hoc network that advertises only basic data rates of 1, 2, 5.5,
or 11 Mbps. So, the list of potential ad hoc networks will include 11b and 11b and 11g, but not
11g. Supported rates remain unchanged, and basic rates are adapted to match those advertised
by the ad hoc network which you are joining in the beacons.
Initiating an ad hoc network
When initiating an 11b only ad hoc network, the following rates 1, 2, 5.5 and 11 Mbps, with 1 and
2 as basic. As other stations join in they down scale their basic rates if required. Protection