Infrastructure Question

I have the Linksys BEFW11S4 WAP that has been working great, but a ping
test I did struck my curiosity about the infrastructure mode. Computer A
is the desktop, and computer B is the laptop. Both machines can ping each
other and the WAP just fine, but it was the WLAN activity light that got my
attention.

As normal, the WLAN is active during WAN activity (in my case, the
internet) because A and B are online through their wireless adapters. When
A or B ping the WAP, the WLAN light blinks with each packet as expected.
But when A and B ping each other, the WLAN light does not blink at all, but
the ping packets are successful.

So I looked up the meaning for infrastructure with Google, and the various
websites said it's a method for wireless clients to communicate with a
wired network - i.e., the internet or if I had any machines connected to
the switch on the WAP.

Does infrastructure dictate that since A and B are wireless clients, the
ping packets between them are not going through the WAP? Or are they still
going through the WAP and the WLAN light doesn't blink at all for internal
traffic? Thanks.

--
Jago