WPA or WiFi Protected Access is a security protocol used to provide users and firms with strong data security and protection for their wireless networks (WiFi) to give them confidence that only authorized users can access their network.
A client must send all frames through the AP to reach any other client or coordinate with the AP to reach another client directly.
Explanation :
In a BSS, the 802.11 standard requires all traffic to pass through an AP. The only exception is the 802.11z amendment, which permits an AP to coordinate direct client-to-client traffic without passing through the AP.
