Which OSPF router type summarizes network advertisements from one OSPF area into another?（）

单项选择题Which type of router cannot exist within a stub area?（）

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

单项选择题Which OSPF area type allows for the flooding of a Type 7 LSA?（）

A.stub
B.transit
C.border
D.not-so-stubby

单项选择题An OSPF non-backbone area allows external routes to be flooded within the area. These external routes are propagated into the backbone. However, external routes from other areas are not allowed to enter this area. Which type of OSPF area does this describe?（）

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

单项选择题What is the purpose of the OSPF hello packet?（）

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

多项选择题What information do OSPF hello packets contain?（）

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