In a RSTP implementation, which of the following two link types are used? （）(Choose two.)

单项选择题As an experienced network engineer, you are asked to troubleshoot a CIS network outage. During the troubleshooting process, you notice that one of your colleagues connects additional devices to the network with the use of his own switch. With the purpose of improving speed, the switch is attached to both network ports in an office, which leads to bridge loop. Enabling which of the following feature will be able to prevent this problem from happening again?（）

A.GLBP
B.RSTP
C.BPDU guard
D.root guard

单项选择题What is the function of the no switchport catalyst switch interface configuration command?（）

A. Disables the interfaces to prevent traffic flow
B. Clears all the configurations on the interface
C. Switches the port from access mode to trunk mode
D. Converts the port from physical Layer 2 port to physical Layer 3 port

单项选择题What is the maximum number of Cisco Catalyst 3750 Series Switches that can be united into a single manageable unit using the Cisco StackWise technology?（）

A.9
B.3
C.12
D.6

单项选择题As a network administrator, you issue the interface auto qos voip cisco-phone command on a port in an edge network. It is possible for a Cisco Catalyst switch to check if a Cisco IP Phone is directly attached to that port by:（）

A. using DHCP snooping
B. snooping the incoming 802.1Q VLAN tag
C. using CDP
D. snooping the CoS marking on the incoming frames

单项选择题What is the most likely reason that an IBGP route that has been selected as a best route is not entered into the IP routing table?（）

A. Route reflectors are not passing updates properly.
B. BGP synchronization has been enabled.
C. The next-hop address is unreachable.
D. No loopback interface has been configured on a router.