A.802.1bB.802.11gC.802.11aD.其余三項(xiàng)都是
A.無(wú)線覆蓋B.點(diǎn)對(duì)點(diǎn)或點(diǎn)對(duì)多C.中繼連接D.其余三項(xiàng)都是
A.底層B.表層C.接入層D.接觸層