Refer to the exhibit. Why has this switch not been elected the root bridge for VLAN1?()A.It has more than one interface that is connected to the root network segment.B.It is running RSTP while the elected root bridge is running 802.1d spanning tree.C.It h

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第2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3题：

Refer to the exhibit. The output that is shown is generated at a switch. Which three of these statements are true? （）

• A、All ports will be in a state of discarding, learning, or forwarding.
• B、Thirty VLANs have been configured on this switch.
• C、The bridge priority is lower than the default value for spanning tree.
• D、All interfaces that are shown are on shared media.
• E、All designated ports are in a forwarding state.
• F、The switch must be the root bridge for all VLANs on this switch.

第4题：

The network administrator has discovered that the power supply has failed on a switch in the company LAN and that the switch has stopped functioning. It has been replaced with a Cisco Catalyst 2950 series switch.What must be done to ensure that this new switch becomes the root bridge on the network?（）

• A、One router is running RIPv1.
• B、RIP neighbor is 224.0.0.9.
• C、The network contains a loop.
• D、Network 10.10.1.0 is reachable.

第5题：

As a network administrator， can you tell me what the root guard feature provides in a bridgednetwork？（）

• A、It ensures that BPDUs sent by the root bridge are forwarded in a timely manner
• B、It enforces the root bridge placement in the network
• C、It ensures that all ports receiving BPDUs from the root bridge are in the forwarding state.
• D、It ensures that the bridge is elected as root bridge in the network.

第6题：

Which statement is correct about RSTP port roles？（）

• A、The designated port is the switch port on every nonroot bridge that is the chosen path to theroot bridge. There can be only one designated port on every switch. The designated portassumes the forwarding state in a stable active topology. All switches connected to a given segment listen to all BPDUs and determine the switch that will be the root switch for a particular segment.
• B、The disabled port is an additional switch port on the designated switch with a redundant link to the segment for which the switch is designated. A disabled port has a higher port ID than the disabled port on the designated switch. The disabled port assumes the discarding state in astable active topology.
• C、The backup port is a switch port that offers an alternate path toward the root bridge. The backup port assumes a discarding state in a stable， active topology. The backup port will be present on nondesignated switches and will make a transition to a designated port if the current designated path fails.
• D、The root port is the switch port on every nonroot bridge that is the chosen path to the root bridge. There can be only one root port on every switch. The root port assumes the forwarding state in a stable active topology.

第7题：

Refer to the output shown on switch SW1 below：  VLAN 1 bridge priority set to 8192. VLAN 1 bridge max aging time set to 20.VLAN 1 bridge hello time set to 2. VLAN 1 bridge forward delay set to 15. Switch is now the root switch for active VLAN 1.  What command would you enter to reproduce this output？

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Refer to Topic TestKing.com in iPAD document.Which switch is the root bridge for VLAN 1?（）

• A、TestKingD
• B、TestKing1
• C、TestKing2
• D、TestKing3

第15题：

Refer to the exibit. Three cisco 2950 switches are set to their default priority sttings.During the spanningtree process,which switch will be elected as the root bridge?（）

• A、Switch3
• B、Switch4
• C、Switch2
• D、Switch1

第16题：

A network administrator needs to force a high-performance switch that is located in the MDF to become the root bridge for a redundant path switched network. What can be done to ensure that this switch assumes the role as root bridge（）。

• A、Establish a direct link from the switch to all other switches in the network.
• B、Assign the switch a higher MAC address than the other switches in the network have.
• C、Configure the switch so that it has a lower priority than other switches in the network.
• D、Configure the switch for full-duplex operation and configure the other switches for half-duplex operation.
• E、Connect the switch directly to the MDF router, which will force the switch to assume the role of root bridge.

第17题：

The network administrator has discovered that the power supply has failed on a switch in the company LAN and that the switch has stopped functioning. It has been replaced with a Cisco Catalyst 2950 series switch. What must be done to ensure that this new switch becomes the root bridge on the network?（）

• A、Lower the bridge priority number.
• B、Change the MAC address of the switch.
• C、Increase the VTP revision number for the domain.
• D、Lower the root path cost on the switch ports.
• E、Assign the switch an IP address with the lowest value.

第18题：

Three switches are connected to one anther via trunk ports.Assuming the default switch configuration,which switch is elected as the root bridge for the spanning-tree instance of vlan 1?（）

• A、the switch with the lowest MAC address
• B、the switch with the higest MAC address
• C、the switch witch the higest IP address
• D、the switch with the lowest IP address

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