Examine the following options，which Spanning Tree Protocol （STP） protection mechanism disables aswitch port if the port receives a Bridge Protocol Data Unit （BPDU）？（）A、Uplink FastB、Port FastC、BPDU GuardD、Root Guard

第1题：

第2题：

Which of the following characteristics describe the BPDU Guard feature？（Choose all that apply.）（）

• A、A BPDU Guard port should only be configured on ports with PortFast enabled
• B、BPDU Guard and PortFast should not be enabled on the same port.
• C、BPDU Guard is used to ensure that superior BPDUs are not received on a switch port
• D、A BPDU Guard port receiving a BPDU will go into err-disable state
• E、A BPDU Guard port receiving a BPDU will be disabled
• F、BPDU Guard can be enabled on any switch port

第3题：

第4题：

What will occur when a nonedge switch port that is configured for Rapid Spanning Tree does not receive a BPDU from its neighbor for three consecutive hello time intervals？（）

• A、RSTP information is automatically aged out.
• B、The port sends a TCN to the root bridge.
• C、The port moves to listening state.
• D、The port becomes a normal spanning tree port.

第5题：

The classic Spanning Tree Protocol （802.1D  1998） uses which sequence of variables to determine the best received BPDU？（）

• A、lowest root bridge id；lowest sender bridge id；lowest port id；lowest root path cost
• B、lowest root path cost；lowest root bridge id；lowest sender bridge id；lowest sender port id
• C、lowest root bridge id；lowest sender bridge id；lowest root path cost；lowest sender port id
• D、lowest root bridge id；lowest root path cost；lowest sender bridge id；lowest sender port id

第6题：

Which of the following characteristics describe the BPDU Guard feature（）

• A、ABPDU Guard port should only be configured on ports with PortFast enabled.
• B、BPDU Guard and PortFast should not be enabled on the same port.
• C、BPDU Guard is used to ensure that superior BPDUs are not received on a switch port.
• D、ABPDU Guard port receiving a BPDU will go into err-disablestate.
• E、ABPDU Guard port receiving a BPDU will be disabled.
• F、BPDU Guard can be enabled on any switch port.

第7题：

Which four Cisco priority Spanning Tree Protocol enhancements are supported with rapid per-VLAN Spanning Tree？ （）

• A、 PortFast
• B、 UplinkFast
• C、 loop guard
• D、 root guard
• E、 BPDU guard
• F、 BackboneFast

第8题：

第9题：

The network administrator has enabled BPDU guard on the LAN.  Why is an effective way to prevent an unauthorized rogue switch from altering the spanning-tree topology of this network？ （）

• A、BPDU guard can be used to prevent invalid BPDUs from propagating throughout the network. 
• B、BPDU guard can guarantee proper selection of the root bridge.
• C、BPDU guard can be utilized to prevent the switch from transmitteing BPDUs and incorrectly altering the root bridge election.
• D、BPDU guard can be utilized along with PortFast to shut down ports when a switch is connected to the port.
• E、None of the other alternatives apply

第10题：

Which statement correctly describes enabling BPDU guard on an access port that is also enabled for PortFast？（）

• A、Upon startup， the port transmits 10 BPDUs. If the port receives a BPDU， PortFast and BPDU guard are disabled on that port and it assumes normal STP operation.
• B、The access port ignores any received BPDU.
• C、If the port receives a BPDU， it is placed into the error-disable state.
• D、BPDU guard is only configured globally and the BPDU filter is required for port-level configuration.