单项选择题 Refer to the exhibit. In this network，R1 is configured not to perform autosummarization within EIGRP. What routes will R3 learn from R2 through EIGRP？（）

多项选择题 WhichthreeportstatesareusedbyRSTP802.1w？（）

问答题 r1isthehub，multipointmodesubinterface，r2andr3isspoke，whenr2downatthespoke，Whatwillr1react？howaboutr3？