单项选择题
A.A
B.B
C.C
D.D
单项选择题 Which statement is true about the frequency of OSPF LSA transmissions?（）
单项选择题 By default, how often does an ERX Edge Router send an OSPF link-state advertisement in a stable network?（）
单项选择题 Which OSPF parameter controls the amount of time it takes to determine if a neighbor has failed?（）
