Much like in an 802.3 Ethernet frame, an 802.11 MAC sublayer address is one of the fol-lowing two types:
- Individual Address Assigned to a unique station on the network (also known as a unicast address).
- Group Address A multiple-destination address, which could be used by one or more stations on a network. There are two kinds of group addresses:
- Multicast-group Group Address An address used by an upper-layer entity to define a logical group of stations.
- Broadcast Address A group address that indicates all stations that belong to the net- work. A broadcast address, all 1 bits, is received by all stations on a local area network. In hexadecimal, the broadcast address would be FF:FF:FF:FF:FF:FF.
The following picture shows four 802.11 MAC address fields respectively called
Address 1, Address 2, Address 3, and Address 4. Depending on how the To DS and From
DS fields are used.
above the picture from CWAP
See the packet capture as the example from the post - MAC header - Frame Control - "To DS" and "From DS" .
You maybe ask when 4 addresses are used. One of examples is WDS: WLAN bridging.
Above the picture from CWAP
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