单项选择题
A. When OSPF is enabled on a LAN interface, and the router is the only router connected to the subnet.
B. When OSPF is enabled on a point - to -point serial link, and that router has both the higher router ID and higher interface IP address on the link.
C. When OSPF is enabled on a Frame Relay point - to - point subinterface, has the lower RID and lower subinterfa ce IP address, and otherwise uses default OSPF configuration on the interface.
D. When OSPF is enabled on a working LAN interface on a router, and the router has been elected BDR.
E. None of the other answers is correct.
单项选择题 A network de sign shows area 1 with three internal routers, area 0 with four internal routers, and area 2 with five internal routers. Additionally, one ABR (ABR1) connects areas 0 and 1, plus a different ABR (ABR2) connects areas 0 and 2. How many Type 1 LSAs would b e listed in ABR2s LSDB?（）
单项选择题 A company has a Frame Relay WAN with one central - site router and 100 branch office routers. A partial mesh of PVCs exists: one PVC between the central site and each of t he 100 branch routers. All routers use point - to - point subinterfaces and one subnet per PVC. Which of the following is true about OSPF in this design?（）
单项选择题 Which of the following settings do not prevent two potential OSPF neighbors from becoming neighbors?（）