多项选择题
Which two features prevent routing loops between the OSPF sites of a customer when the sites aremultihomed or a backdoor link is used between the sites？ （）
A.sham link B.down bit C.virtual link D.Site of Origin E.domain tag
单项选择题 InwhichCiscoIOSconfigurationmodeistheroutedistinguisher（RD）configured？（）
多项选择题 WhichtwostatementsaboutMPLSpoint-to-multipointtrafficengineering（P2MPTE）aretrue？（）
单项选择题 WhichstatementaboutATMAAL5overMPLSistrue？（）
