A.TC B.V1G C.V0G D.V2G
A.下層的數(shù)據(jù)通信 B.中間層的實(shí)時(shí)數(shù)據(jù)庫(kù) C.中間層的信息監(jiān)控 D.上層的信息應(yīng)用層