单项选择题 Refer to the exhibit. You have noticed that several users in the network are consuming a great deal of bandwidth for the peer-to-peer application Kazaa2. You would like to limit this traffic， and at the same time provide a guaranteed 100 kb/s bandwidth for one of your servers. After applying the configuration in the exhibit， you notice no change in the bandwidth utilization on the serial link； it is still heavily oversubscribing the interface. What is the cause of this problem？（）

问答题 OSPF的域间路由通告行为？问R1能够将AREA1通告给AREA0的域间路由在通告回AREA1吗？为什么？

多项选择题 Refer to the exhibit. Users from the Engineering VLAN complain that every time Business VLAN users have a network connectivity issue，the Engineering VLAN users usually have problems experiencing slow response or network connectivity problems. After troubleshooting， anunauthorized switch 2 was found.This unauthorized switch has been a regular problem， assuming the root bridge function under thespanning-tree domain and causing the Engineering VLAN to be unstable. Which three of these actionscould be suggested to fix the problem？（）