单项选择题
In PIM-SM operations，to which device does the first router that connects with the multicast source sendthe register message？（）
A.RP B.multicast source C.IGMP router D.multicast receiver E.PIM designated router
单项选择题 WhatarethedefaultvaluesforGREtunnelkeeplivetimeandnumberofretries？（）
单项选择题 HowmanymessagesdoesInternetKeyExchangeusetonegotiateSAcharacteristicwhenitrunsinaggressivemode？（）
单项选择题 WhichstatementaboutSNMPistrue？（）
