At which layer of the OSI model is RSTP used to prevent loops?（）

Which command encrypts all plaintext passwords?（）

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

If all OSPF routers in a single area are configured with the same priority value,what value dose a router use for the ODPF router ID in the absence of a loopback interface?（）

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?（）

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?（）

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?（）

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

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

Which statement describes the rule of split horizon?（）