A.Tunnel和PW中不能同时部署OAM
B.OAM不能用于检测链路的连通性,只能用于隧道的连通性检测
C.PTN3900和PTN6900对接创建Tunnel时,MPLS OAM模式必须选择为IETF标准
D.环网OAM的检测模式,支持“Y.1711”和“Y.1731”两种
A.如果供电设备供给的电压是-48V,应拆除J3202和J3201的跳线帽
B.如果供电设备供给的电压是-60V,应保留J3202和J3201的跳线帽
C.如果供电设备供给的电压是-48V,应保留J3202和J3201的跳线帽
D.如果供电设备供给的电压是-60V应拆除J3202和J3201的跳线帽
It is implied in the passage that ______. ()
A.governments and companies had different opinions about the safety of products
B.governments paid little attention to the safety of products
C.government officials often did not listen to scientists
D.in the past no safety laws were introduced by governments