单项选择题
Where is OSPF authentication configured on the ERX Edge Router?（）
A.A B.B C.C D.D
During OSPF adjacency formation, in which state is a ro...
During OSPF adjacency formation, in which state is a router in when an OSPF hello packet has been sent but bi-directional communication has not been achieved?（）
During OSPF adjacency formation, in which state is a router in when it is negotiating to be in charge of the database synchronization process?（）
