how to add old airport extreme 11g to new airport extreme 11n to extend network?
I am trying to use my old Airport Extreme 11g to extend my wireless network from my newer Airport Extreme 11n. Are they compatible?
They are, but you may want to think twice before using this approach. The reasons are: 1) The extended network will only operate in the 802.11g Radio Mode, and 2) The overall bandwidth will be reduced by half for each base station added. Since this will be a "g" network, you'd be getting around 25-27 Mbps maximum of bandwidth.
If you still would like to pursue this, please check out the following Apple Support article for the details.