单项选择题
A. Summarized routes are unacceptable
B. They will appe ar in the OSPF routing table as type E2 routes
C. Only routes with lower administrative distances will be imported
D. All imported routes are to be automatically summarized if possible
多项选择题 Which two routing protocols require a metric to be configured when redistributing routes from other protocols?（）
单项选择题 Refer to the exhibit. Routers R1 and R2 have been configured to operate with OSPF. Routers R1 and R3 have been configured to operate with RIP. After configuring the redistribution between OSPF a nd RIP on R1, no OSPF routes are distributed into RIP. What should be done to correct this problem? （）
单项选择题 Refer to the exhibit. What is required to complete the IPv6 routing configurations shown?（）