While troubleshooting a network problem,a technician discovers that the current copy of the Cisco IOS is outdated and needs to be updated.Which of the following commands would the technician issue to replace the Cisco router IOS with the newer version?（）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 device might be installed at a branch office to enable and manage an IPsec site-to-site VPN?（）

After the show ip route command has been entered,the follwing routes are displayed.Which route will not be entered into the routing table of a neighboring router?（）

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

An employee of ABC company has move to an office on a different floor. Although the administrator is able to telnet to all of the routers,the address of Switch F is needed in order to verify that the employee remains in the same VLAN.Which action could be used by the administrator to find the IP address of Switch F?（）

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?（）

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

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

Which statement describes the rule of split horizon?（）

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?（）