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?（）

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?（）