Apple AirPort Extreme 802.11n (5th Generation) - Manual (Page 14)

14 Chapter 2 AirPortExtremeNetworks
UsingtheAirPortExtremewithaBroadbandInternetService
When you set up your AirPort Extreme to provide network and Internet access, Mac
computers with AirPort and AirPort Extreme Cards, and 802.11a, 802.11b, 802.11g, and
IEEE 802.11n specification wireless-equipped computers can access the wireless AirPort
network to share files, play games, and use Internet applications like web browsers and
email applications.
It looks like this:
DSL or cable modem Internet WAN port
to Internet
<
2.4 GHz
2.4 or 5 GHz