多项选择题
A.The hello time is 5 seconds.
B.The forward delay is 10 seconds.
C.The hello time is 2 seconds.
D.The forward delay is 15 seconds
E.The max_age timer is 15 seconds.
F.The hello time is 10 seconds.
G.The max_age timer is 20 seconds.
H.The forward delay is 20 seconds.
I.The max_age timer is 30 seconds.