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

While troubleshooting a network problem,a technician discovers that the current copy of the Cisco IOS is outdated and needs to be updated.Which of the following commands would the technician issue to replace the Cisco router IOS with the newer version?（）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

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

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?（）

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

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

What is the result of issuing the frame-relay map ip 192.168.1.2 202 broadcast command?（）

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?（）

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