单选题Which switch would STP choose to become the root bridge in the selection process?（）A 32768: 11-22-33-44-55-66B 32768: 22-33-44-55-66-77C 32769: 11-22-33-44-55-65D 32769: 22-33-44-55-66-78

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第3题：

Which two of the following values does STP take into consideration when it elects the root bridge?（）

• A、The BPDU version number
• B、The access layer bridge setting
• C、The Bridge ID
• D、The spanning-tree update number
• E、The bridge priority
• F、The VLAN number

第4题：

What are the switch and bridge port characteristics of a layer two spanning-tree network that is fully converged?（）

• A、All switch and bridge ports are in the forwarding state.
• B、All switch and bridge ports are in the stand-by state.
• C、All switch and bridge ports are assigned as either root or designated ports.
• D、All switch and bridge ports are in either the forwarding or blocking state.
• E、All switch and bridge are either blocking or looping.

第5题：

Which three statements about STP timers are true？（）

• A、STP timers values （hello， forward delay， max age） are included in each BPDU.
• B、A switch is not concerned about its local configuration of the STP timers values. It will only consider the value of the STP timers contained in the BPDU it is receiving.
• C、To successfully exchange BPDUs between two switches， their STP timers value （hello， forward delay， max age） must be the same.
• D、If any STP timer value （hello， forward delay， max age） needs to be changed， it should at least be changed on the root bridge and backup root bridge.
• E、On a switched network with a small network diameter， the STP hello timer can be tuned to a lower value to decrease the load on the switch CPU.
• F、The root bridge passes the timer information in BPDUs to all routers in the Layer 3 configuration.

第6题：

Which two values are used by Spanning Tree Protocol to elect a root bridge (Choose two.)（）。

• A、amount of RAM
• B、bridge priority
• C、IOS version
• D、IP address
• E、MAC address
• F、speed of the links

第7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8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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第14题：

In the Cisco FabricPath domain， one switch becomes the root for the multidestination tree. Cisco FabricPath switches compare which three parameters to select the root？ （）

• A、 Root priority
• B、 System ID
• C、 Bridge ID
• D、 Switch ID
• E、 Port ID
• F、 Subswitch ID

第15题：

Why would an administrator change the value of the spanning-tree priority of a switch?（）

• A、in order to optimize the path that frames take from source to destination
• B、to increase the priority so a designated port will become a root port
• C、to increase the BID, so the switch is more likely to become root bridge
• D、in order to allow VLANs to be sent from one switch to another across a single link
• E、to force a given switch to become an STP server

第16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17题：

Which switch would STP choose to become the root bridge in the selection process?（）

• A、32768: 11-22-33-44-55-66
• B、32768: 22-33-44-55-66-77
• C、32769: 11-22-33-44-55-65
• D、32769: 22-33-44-55-66-78

第18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19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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