PON网络维护中需要注意的事项有（）

以下不属于B类地址的网络掩码是（ ）

OSPF 协议生成路由分为四类，针对路由说法正确的是：

关于OSPF划区域说法不正确的为：

OSPF路由协议中，关于stub区域说法不正确的是？

OSPF 中，一台路由器能同时作为以下哪几种组合的类型（ ）

Which of the following OSPF LSAs are supported by the Totally Stubby type?

在设计一个多区域的OSPF网络的时候，下列哪些应该考虑？

When designing OSPF networks, it is not recommended to have an excessive number of routers in any single area. Which two of the following statements describe the consequences of having too many routers in an area

Router_A has an interface in one OSPF area and another interface in a different OSPF area. What kind of router is Router_A

OSPF 中的骨干区域内肯定不存在以下哪些类型的LSA（ )