2020 52 net work OSPF protocol in the scope of the DR is that (),
A. an area b. c. that A segment A router d. running OSPF protocol network
The answer is B
Analytic: the scope of OSPF protocol of DR is a network segment
DR designated router, is responsible for broadcasting multiple network establishment and maintenance of the adjacency relations and is responsible for the synchronization of LSA,
DR form adjacency relations with all other routers and exchange link state information, not direct exchange between other routers link-state information, thus greatly reduce the MA adjacency relations in the network data and exchange of link-state information consumption of resources,
DR once appear, fault, adjacency relationship between its and other routers will all failure, can't synchronize link-state database, where you need to election DR, establish adjacency relations with the DR router again, complete the LSA synchronization, in order to avoid a single point of failure risk, electoral backup designated router BDR, quickly take over the work of Dr. When DR failure,

From analytical wouldn't know it is a network segment, don't know how to understand?