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?（）

Which statement describes the rule of split horizon?（）

Which protocol reduces administrative overhead in a switched network by allowing the configuration of a new VLAN to be distributed to all the switches in a domain?（）

A network administrator needs to configure a serial link between the main office and a remote location.The router at the remote office is a non-cisco router. How should the network administrator configure the serial interface of the main office router to make the connection?（）

When you are troubleshooting an ACL issue on a router,which command can help you to verify which interfaces are affected by the ACL?（）

Which device might be installed at a branch office to enable and manage an IPsec site-to-site VPN?（）

At which layer of the OSI model dose PPP perform?（）

How are VTP advertisements delivered to switches across the network?（）

An administrator must assign static IP addresses to the servers in a network.For network 192.168.20.24/29, the router is assigned the first usable host address while the sales server is given the last usable host address. Which of the following should be entered into the IP propertied box for the sales server?（）

Which IPsec security protocol should be used when confidentiality is required?（）