多项选择题
A. Routers cannot redistribute external routes into the area.
B. Routers should have zero Type 3 LSAs in their LSDBs.
C. Routers should have zero Type 5 LSAs in their LSDBs.
D. Routers should learn default routes from the ABRs attached to the area.
单项选择题 Router R1, an ASBR connected to the Internet and to backbone area 0, has been configured with a default - information originate command. Which of the following is true about the effects of this configuration command?（）
单项选择题 The following output exists on Router R1, a router internal to area 1. What can you d etermine as true from the output of the show ip ospf database summary command?（）
多项选择题 R1, an ABR between backbone area 0 and area 1, has intra - area routes in area 0 for 10.1.1.0/24,10.1.2.0/24, and 10.1.3.0/24. These routes have metrics of 21, 22, and 23, respectively. An engineer then adds the area 0 r ange 10.1.0.0 255.255.0.0 command under the OSPF process of R1. Which of the following is true?（）