Three switches are connected to one anther via trunk ports.Assuming the default switch configuration,which switch is elected as the root bridge for the spanning-tree instance of vlan 1?（）

The network administrator cannot to switch 1 over a telnet session,although the hosts attached to switch 1 can ping the interface Fa0/0 of the router.Given the information in the graphic and assuming that the router and switch2 are configured properly,which of the following commands should be issued on switch 1 to correct this problem?（）

On which options are standard access list based?（）

Which statement describes the rule of split horizon?（）

Which command displays the CHAP authentication process as it occurs between two routers?（）

While troubleshooting a network problem,a technician discovers that the current copy of the Cisco IOS is outdated and needs to be updated.Which of the following commands would the technician issue to replace the Cisco router IOS with the newer version?（）

Which address is the IPV6 all-RIP-routers muticast group address that is used by RIPng as the destaion address?（）

What is the purpose of the cisco Vlan Trunking protocol?（）

Which pairing reflects a correct protocol-and-metric relationship?（）

You have been asked to come up with a subnet mask that will allow all three web servers to be on the same network while providing the max number of subnets.Which network address and subnet mask meet this requirement?（）