What is the purpose of the STP PortFast BPDU guard feature？（）A、enforce the placement of the root bridge in the networkB、ensure that a port is transitioned to a forwarding state quickly if a BPDU is receivedC、enforce the borders of an STP domainD、ensure th

第1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2题：

What is the STP root guard feature designed to prevent？（）

• A、a root port being transitioned to the blocking state
• B、a port being assigned as a root port
• C、a port being assigned as an alternate port
• D、a root port being transitioned to the forwarding state

第3题：

第4题：

If a port configured with STP loop guard stops receiving BPDUs， the port will be put into which state？（）

• A、learning state
• B、listening state
• C、forwarding state
• D、root-inconsistent state

第5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6题：

Switch R1 has been configured with the root guard feature.  What statement is true if the spanning  tree enhancement Root Guard is enabled？ （）

• 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.

第7题：

After configuring FabricPath， the following appears in the syslog：  %STP-2-L2GW_BACKBONE_BLOCK： L2 Gateway Backbone port inconsistency blocking port port-channel100 on VLAN0010.  What is the cause of this message？ （）      

• A、 STP must be disabled； message indicates that STP is enabled.
• B、 STP is misconfigured； root guard must be disabled.
• C、 An inferior BPDU is received on a Cisco FabricPath edge port.
• D、 A superior BPDU is received on a Cisco FabricPath edge port.

第8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9题：

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 Fast
• B、Port Fast
• C、BPDU Guard
• D、Root Guard

第10题：

Which two statements correctly describe characteristics of the PortFast feature？ （）

• A、STP will be disabled on the port.
• B、PortFast can also be configured on trunk ports.
• C、PortFast is required to enable port-based BPDU guard.
• D、PortFast is used for both STP and RSTP host ports.
• E、PortFast is used for STP-only host ports.