单项选择题
A.OSPF external LSAs are automatically flooded into all OSPF areas， unlike type 7 LSAs， which require that redistribution be configured.
B.External LSAs （type 5） are automatically changed to type 1 LSAs at ASBRs.
C.Type 5 LSAs are route summaries describing routes to networks outside the OSPF Autonomous System.
D.External network LSAs （type 5） redistributed from other routing protocols into OSPF are not permitted to flood into a stub area.
单项选择题 ThisquestionisabouttheformationofOSPFadjacency.AnOSPFadjacencywillnotformcorrectlyacrossapoint-to-pointlinkinthesamearea.Whichwouldmostlikelycausethisproblem？（）
问答题 WhatisNBAR？
单项选择题 Refer to the exhibit. Router E learned about the PIM RP （designated as 7.7.7.7） from four different sources. Routers A and D advertised the 7.0.0.0 network via EIGRP. Routers B and C advertised the 7.0.0.0 network via OSPF. Considering that all four Ethernet interfaces on router E could potentially lead back to the PIM-RP， when router E receives the first multicast packet down the shared tree， which incoming interface will be used to successfully pass the RPF check？（）