A、 OSPF stub areas can be thought of as a simple form of summarization

B、 OSPF cannot filter intra area routes

C、 An ARR ran only exist in two areas - the backbone and one adjacent area

D、 Performance issues in the Backbone area can be offset by allowing some traffic to transit anon-backbone area

E、 the size of an area （the LSDB） will be constrained by the size of the IP MTU