How many MAC address fields are present in an 802.11 data frame sent from a wireless station to a host on a wired network?

How many MAC address fields are present in an 802.11 data frame sent from a wireless station to a host on a wired network?

• A. Three
• B. Two
• C. One
• D. Four

Answer: (A)

In 802.11 frames, the number of MAC address fields depends on whether the frame crosses the wireless distribution system (DS). When a wireless station sends data to a host on the wired network (in infrastructure mode), the frame travels from the station to its AP and then onto the wired network. In this path, three address fields are used: Address 1 is the Receiver Address (the AP’s MAC), Address 2 is the Transmitter Address (the station’s MAC), and Address 3 is the Destination Address (the final host on the wired side). Address 4 is only added when the frame needs to be bridged across the DS between APs, which isn’t the case here. So three MAC address fields are present.

In 802.11 frames, the number of MAC address fields depends on whether the frame crosses the wireless distribution system (DS). When a wireless station sends data to a host on the wired network (in infrastructure mode), the frame travels from the station to its AP and then onto the wired network. In this path, three address fields are used: Address 1 is the Receiver Address (the AP’s MAC), Address 2 is the Transmitter Address (the station’s MAC), and Address 3 is the Destination Address (the final host on the wired side). Address 4 is only added when the frame needs to be bridged across the DS between APs, which isn’t the case here. So three MAC address fields are present.