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

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 cisco ios command can help to determine the timing of various debug events,relative to each other,when you are debugging a complicated router issue?（）

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?（）

Three access ports have been installed and configured to a small office.What term defines the wireless topology?（）

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

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 encapsulation type is a Frame Relay encapsulation type that is supported by Cisco routers?（）

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

Which name describes an IPV6 host-enable tunneling technique that uses IPV4 UDP,does not require dedicated gateway tunnels,and can pass through existing IPV4 NAT gateways?（）