单项选择题 If all OSPF routers on a broadcast network have the same OSPF priority, what parameter is used to determine the new BDR at the time of a DR failure?（）

单项选择题 What is the purpose of the OSPF link-state update packet?（）

单项选择题 Why would you make a non-backbone area a stub or not-so-stubby area?（）