OSPF is a link-state routing protocol. It is designed to be run internal to a single (1) system. Each OSPF router maintains an identical(2) describing the autonomous system's topology. From this database, a routing table is calculated by constructing a shortest-path (3).OSPF recalculates routes quickly in the face of topological changes, utilizing aminimum of routing (4) traffic. OSPF provides support for equal-cost multipath. An area routing capability is provided, enabling.an additional level of routing protection and a reduction in routing protocol (5).
空白（5）处应选择（）
A.flow
B.state
C.traffic
D.stream
参考答案：C
解析：
OSPF是一种链路状态协议，用于单个自治系统内部。每个OSPF路由器都维持一个相同的描述自治系统拓扑结构的数据库。通过这个数据库可以构造出最短通路树，从而计算出路由表。当拓扑结构改变时，OSPF能很快计算出路由，但是使用了最小的路由协议流量。OSPF支持等费用的多条通路。OSPF的区域路由能力提供了附加的路由保护功能，也减少了路由协议的流量。