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

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

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?（）

What is the subnetwork address for a host with the IP address 201.100.5.68/28?（）

Which command is used to display the collection of OSPF link states?（）

On which options are standard access list based?（）

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

A network administrator is planning a network installation for a large organization.The design requires 100 separate subnetworks,so the company has acquired a Class B network address.What subnet mask will provide the 100 subnetworks required, if 500 usable host addresses are required per subnet?（）

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