A. Singlemode fiberB. Multimode fiberC. Shielded twiste……

单项选择题Which of the following protocols requests membership to a multicast group?（）

A.IGMP
B.SNMP
C.SMTP
D.ICMP

单项选择题A small amount of spoofed packets are being sent across a network and a large amount of reply packets are being sent back to the network resource. Which of the following BEST describes this security threat?（）

A.Worm
B.Smurf
C.Logic Bomb
D.Man-in-the-middle

单项选择题Which of the following is a hybrid network topology used for fault tolerance, in which all computersMUST connect to each other?（）

A.Star
B.Ring
C.Bus
D.Mesh

单项选择题An administrator replaced a router with a switch. End users are able to access network shares butare not able to access the Internet. Which of the following is the BEST explanation why the usersare unable to access the Internet?（）

A. Router routes traffic between different networks and a switch does not
B. The new switch is faulty and needs to be replaced and configured correctly
C. The firewall needs to be setup to allow traffic to reach the Internet
D. The switch needs to be setup to forward data traffic to the Internet

单项选择题Which of the following logical network topologies is used to provide a secure connection acrossthe Internet?（）

A.VLAN
B.Peer to Peer
C.VTP
D.VPN