简答题 What is an RPF check？

多项选择题Refer to the exhibit. From the MAC addresses shown in the command output， to which two ports is the multicast stream 225.230.57.199 being forwarded on this switch？ （）

A.Fa6/28
B.Fa7/20
C.Gi3/7
D.Fa4/2
E.Fa4/14
F.Fa4/38

单项选择题WhichstatementbestdescribesOSPFexternalLSAs（type5）？（）

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？（）

A.Each interface has a different OSPF cost.
B.Each interface is configured with secondary addresses as well as primary addresses.
C.Each interface has a different MTU size.
D.Each interface is configured with theip unnumbered loopback 0 command.

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？（）

A.E0
B.E1
C.E2
D.E3
E.None of these interfaces will be used to successfully pass the RPF check
F.All of these interfaces would successfully pass the RPF check