A. IEEE 802.1s （MST）
B. IEEE 802.1Q （CST）
C. Cisco PVST+
D. IEEE 802.1d （STP）
E. None of the other alternatives apply

A. To enhance Spanning Tree troubleshooting on multilayer switches
B. To reduce the total number of spanning tree instances necessary for a particular topology 
C. To provide faster convergence when topology changes occur in a switched network
D. To provide protection for STP when a link is unidirectional and BPDUs are being sent but not  received
E. None of the other alternatives apply

A. To verify the MST configuration， the show pending command can be used in MST configuration  mode.
B. When RSTP and MSTP are configured； UplinkFast and BackboneFast must also be enabled.
C. All switches in the same MST region must have the same VLAN-to-instance mapping， but  different configuration revision numbers.
D. All switches in an MST region， except distribution layer switches， should have their priority  lowered from the default value 32768.
E. An MST region is a group of MST switches that appear as a single virtual bridge to adjacent  CST and MST regions.
F. Enabling MST with the "spanning-tree modemst" global configuration command also enables  RSTP.

A. Enables all fiber-optic LAN ports for Unidirectional LINK Detection （UDLD）
B. Enables all copper media LAN ports Unidirectional Link Detection （UDLD）
C. Overrides the default UDLS setting for all ports
D. Globally enables all ports on the device for Unidirectional Link Detection （UDLS）
E. None of the other alternatives apply

A. If BPDUs are not received on a non-designated port， the port is moved into the STP loop- inconsistent blocked state
B. IF BPDUs are received on a PortFast enabled port， the port is disabled.
C. If superior BPDUs are received on a designated port， the interface is placed into the root- inconsistent blocked state.
D. If inferior BPDUs are received on a root port， all blocked ports become alternate paths to the  root bride.