多项选择题
A.A
B.B
C.C
D.D
E.E
单项选择题 Where is OSPF authentication configured on the ERX Edge Router?（）
单项选择题 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?（）
单项选择题 During OSPF adjacency formation, in which state is a router in when it is negotiating to be in charge of the database synchronization process?（）
