单项选择题
A. Internal routers within the backbone area (area 0)
B. Internal routers within the NSSAs
C. Internal routers within the stubby areas
D. ASBRs
E. ABRs
F. DRs and BDRs
单项选择题 When verifying OSPF virtual link problems, which is an important item to check on the two transit OSPF routers?（）
多项选择题 When verifying the OSPF link state database, which type of LSAs should you expect to see within the different OS PF area types?（）
多项选择题 You are troubleshooting an OSPF problem where external routes are not showing up in the OSPF database. Which two options a re valid checks that should be performed first to verify proper OSPF operation?（）