What is the default authentication method on an OSPF interface?（）

多项选择题What are the three OSPF authentication methods supported on the ERX Edge Router?（）

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?（）

A.A
B.B
C.C
D.D

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?（）

A.A
B.B
C.C
D.D

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?（）

A.A
B.B
C.C
D.D

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?（）

A.A
B.B
C.C
D.D