WhichtworestrictionsmusttheEnterpriseCampusnetworkdesignerconsiderwhenevaluatingWANconnectivityoptions？（）

A.OSPFovermulticastEMSorVPLSnetworkmaynothaveconsistentbroadcastormulticastperformance
B.IPmulticastisnotsupportedoverLover3MPLSVPN；insteadaLayer2MPLSWNmustbeutilizedwithserviceprovidersupport
C.QoSrequirementswithMPLS-VPNmustbeimplementedbytheserviceprovider
D.HierarchicalVPLSdesignsaretheleastscalable
E.IGMPsnoopingisnotonoptionwithVPLSorEMS；insteadadministrativescopingorallowingsufficientbandwidthforunnecessarymulticasttrafficattheedgelinksisrequired

【参考答案】

A, C