单项选择题
A.IPv6 multicast uses Multicast Listener Discovery.
B.The first 8 bits of an IPv6 multicast address are always FF （1111 1111）.
C.IPv6 multicast requires MSDP.
D.PIM dense mode is not part of IPv6 multicast.
单项选择题 InFrameRelay，FECNmessagesindicatingcongestionaresentorreceivedbywhichoffollowing？（）
单项选择题 Priorto802.1w，Ciscoimplementedanumberofproprietaryenhancementsto802.1DtoimproveconvergenceinaLayer2network.Whichstatementiscorrect？（）
单项选择题 Auserhasnonetworkconnectivity.Acheckoftheassociatedportindicatesthattheinterfaceisup，thelineprotocolisdown.Whichitemwouldmostlikelycausethisproblem？（）