How Access points differentiate stations?

Question

I'm doing a ping from a station to another connected on the same access point. Given the fact that they are both on Wi-fi interface, how can access point know where to forward a packet?

Answer 1

That is what MAC addresses are used for. A bridge (switch, WAP, etc.) maintains a MAC address table. The table tells the device the interface where it has last ween the MAC address as a source address, and it will forward any frames with that destination MAC address to the same interface where it last saw it as the source MAC address.

Answer 2

Another important concept is the ARP (MAC Address to IP address mapping) on the client machines. This will enable the sender of the ping (ICMPs) and the receiver information about whom on the WLAN to send the packet to. Traditionally the list is called an assoc-list.