CCNA中英对照题库(选择题)

CCNA（200-120）题库中英对照
整理于：2015年3月31日
版本：1.2
声明：
本题库来源互联网（鸿鹄论坛）
本题库为英文考试原版左右选择题
中文考试为随机抽取英文题的中译版
此题库非中文考试题库，而是英文题库手动翻译
此题库为手工个人翻译，存在错误和不妥难免，不代表任何官方
机构和组织
本题库旨在更好的理解英文原本题库，也可以用于中文考试参考
用。

如发现任何错误或不当之处，可以自行修改，但请更新版本以免混乱，也可致上传者。

QUESTION001
Refer to the exhibit. What will Router1 do when it receives the data frame shown? (Choose three.) 参照下图，这个图示显示了Ｒ１接受到如图所示数据帧的时候会怎么做？
Router1 will strip off the source MAC address and replace it with the MAC
address 0000.0c36.6965.
Ｒ１会剥离源ＭＡＣ地址，以0000：0C36.6965代替。

Router1 will strip off the source IP address and replace it with the IP address 192.168.40.1. Ｒ１会剥离源IP地址，以192.168.40.1代替。

Router1 will strip off the destination MAC address and replace it with the MAC address 0000.0c07.4320.
Ｒ１会剥离源ＭＡＣ地址，以0000：0C36.6965代替。

Router1 will strip off the destination IP address and replace it with the IP address of 192.168.40.1.
Ｒ１会剥离目的IP地址，以192.168.40.1代替。

Router1 will forward the data packet out interface FastEthernet0/1.
R1将会从F0/1转发这个数据包。

F. Router1 will forward the data packet out interface FastEthernet0/2. R1将会从F0/2转发这个数据包数据传输过程中，IP 地址不变，但是在不同的网段中，MAC 地址要根据设备的具体情况而发生改变。

在
不同网络中，依靠 IP 地址定位，在同一网络中，依靠 MAC 地址定位。

QUESTION002
Refer to the exhibit. Which three statements correctly describe Network Device A? (Choose three.)
如图所示，关于网络设备 A 哪三项是正确的描述？
With a network wide mask of 255.255.255.128, each interface does not require an IP address.
如果配置一个 25 位的网络号，每个端口不需要配置一个地址。

With a network wide mask of 255.255.255.128, each interface does require an IP address on
a unique IP subnet.
如果配置一个 25 位的网络号，每个端口需要配置一个地址和子网。

With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other.
如果配置一个 24 位的网络号，成为一个二层设备以便让 PC 和其他设备通讯。

With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other.
如果配置一个 24 位的网络号，成为一个三层设备以便让 PC 和其他设备通讯。

E.With a network wide mask of 255.255.254.0, each interface does not require an IP address. 如果配置一个 23 位的网络号，每个端口不需要配置一个地址。

QUESTION003
Which layer in the OSI reference model is responsible for determining the availability of the receiving program and checking to see if enough resources exist for that communication?
在 OSI 参考模型当中，哪一层可以判断程序的可用性以机是否有足够的资源来支持这个通讯？
transport 传输层
network 网络层
presentation 表示层
D. session 会话层
E. application 应用层
QUESTION004
Which of the following describes the roles of devices in a WAN? (Choose three.)
下列哪些描述广域网设备的作用？
A CSU/DSU terminates a digital local loop
联系数字本地环路
A modem terminates a digital local loop
A CSU/DSU terminates an analog local loop
A modem terminates an analog local loop 一个模拟信号
A router is commonly considered a DTE device
路由器通常是 DTE 设备
A router is commonly considered a DCE device
路由器通常是 DCE 设备
QUESTION005
Refer to the exhibit, Host A pings interface S0/0 on router 3, what is the TTL value for that ping? 如图所示，主机 A 的 ping 路由器 3 的 S0/0 接口，TTL 值会是多少？
253
252
255
254
QUESTION006
A network administrator is verifying the configuration of a newly installed host by establishing an FTP connection to a remote server. What is the highest layer of the protocol stack that the nework administrator is using for this operation?
网络管理员验证的配置是一个新安装的主机通过建立 FTP 连接到远程服务器。

网络管理员这个操作使用的最高协议层是什么？
application presentation session
transport
internet
data link
FTP 协议属于应用层
QUESTION007
Refer to the exhibit. After HostA pings HostB, which entry will be in the ARP cache of HostA to support this transmission?
如图所示，主机Ａping 主机 B，在此通信中，以下哪个列表将会进入主机 A 的 ARP 缓存？
A.
B.
C.
D. E.
F.
QUESTION008
A network interface port has collision detection and carrier sensing enabled on a shared twisted pair network. From this statement, what is known about the network interface port?
在一个双绞线网络中的一个网络接口上监测到网络冲突，冲这个表述中，有关这个网络接口，哪一项是正确的？
This is a 10Mb/s switch port.
This is a 100Mb/s switch port.
This is an Ethernet port perating at half duplex.
This is an Ethernet port operating at full duplex.
This is a port on a network interface card in a PC.
半双工模式会产生冲突，全双工模式不会产生冲突
QUESTION009
A receiving host computes the checksum on a frame and determines that the frame is damaged.The frame is then discarded.At which OSI layer did this happen?
收到一个主机发来的帧并进行校验以确认是否损坏，然后丢弃。

这个过程在 OSI 哪一层发生？
session
network
Physical
data link
Transport
传输层：数据段，segment网络
层：数据包，数据报，packet数
据链路层：数据帧，frame
QUESTION010
Which of the following correctly describe steps in the OSI data encapsulation process? (Choose two.)
以下那些正确描述了 OSI 数据封装的过程？
The transport layer divides a data stream into segments and may add reliability and flow control information.
传输层将数据分段，并且加上可靠性和流控制信息。

B.The data link layer adds physical source and destination addresses and an FCS to the
segment.
数据链路层会添加物理原和目的地址以及 FCS 校验字段，然后给数据段。

Packets are created when the network layer encapsulates a frame with source and destination host addresses and protocol-related control information.
当网络层封装数据帧的时候，添加源和目的主机地址已经协议控制信息，形成数据包。

Packets are created when the network layer adds Layer 3 addresses and control information to a segment.
网络层添加三层地址和控制信息给数据段，从而形成数据包。

E.The presentation layer translates bits into voltages for transmission across the physical link. 表示层会将数据转换成电平给物理链路传输。

每一层只能接收来自上一层的数据并进行封装
QUESTION011
Refer to the graphic.Host A is communicating with the seiver. What will be the source MAC address of the frames received by Host A from the server?
参考以下图片，主机 A 和服务器之间的通信，主机 A 收到服务器发来的数据帧，那么原 MAC 地址会是什么？
the MAC address of the seiver network interface
the MAC address of host A
the MAC address of router interface e 1
the MAC address of router interface e0
QUESTION012
Refer to the exhibit.What two results would occur if the hub were to be replaced with a switch that is configured with one Ethernet VLAN?(choose two)
如图所示，在一个以太网 VLAN 中，如果集线器用交换机代替，将会出现哪两个结果？
The number of collision domains would decrease.
冲突域将会减少
The number of collision domains would increase.
冲突域将会增加。

The number of broadcast domains would remain the same.
广播域不会改变
The number of collision domains would remain the same.
冲突域不会改变
The number of broadcast domains would increase.
广播域将会增加。

QUESTION013
Which three statements accurately describe layer 2 Ethernet switches?(choose three)
下列哪三项准确的描述了二层以太网交换机？
Microsegmentation decreases the number of collisions on the network.
在网络中，网络分段减少了冲突的数量。

if a switch receives a frame for an unkown destination,it uses ARP to resolve the address.
如果一个交换机接受到一个未知目的帧，他们使用 ARP 来决定这个地址。

Spanning Tree Protocol allows switches to automatically share vlan information.
生成树协议允许交换机自动分享 vlan 信息。

In a properly functioning network with redundant switched paths,each switched aegment will contain one root bridge with all its ports in the forwarding state.All other switches in that broadcast domain will have only one root port.
在一个具有冗余链路的交换网络中，会包含一个根桥，且每个端口都处于转发状态，在这个广播域中，其他交换机有且只有一个根端口。

E.Establishing vlans increases the number of broadcast domains.
创建 vlan 能够增大广播域数量。

Switches that are configured with vlans make forwarding decisions based on both layer 2 and
layer 3 address information.
交换机的 vlan 策略配置，是基于二层和三层地址。

QUESTION014
Where does routing occur within the DoD TCP/IP reference model?
在 DOD 的 TCP/IP 参考模型中，路由发生在哪一层？
application
internet
network
transport
DoD 模型：
● 应用层（ Application） ●
主机到主机层（ Host to Host）
● 网络互连层（ Internet）
网络访问层（ Network Access）
OSI 模型：
物理层( Physical)
数据链路层( DataLink)
网络层( Network)
传输层( Transport)
会话层( Senssion)
表示层( Presentation)
应用层( Application)
QUESTION015
Which destination addresses will be used by Host A to send data to Host C? (Choose two.) 主机Ａ发送数据到主机Ｃ，会使用哪个目的地址？
the IP address of Switch 1 the MAC address of Switch 1 the IP address of Host C
the MAC address of Host C
the IP address of the router's E0 interface
the MAC address of the router's E0 interface
QUESTION016
For what two purposes does the Ethernet protocol use physical addresses? (Choose two.)
使用武力地址的两个目的是什么？
to uniquely identify devices at Layer 2
在二层上识别设备。

to allow communication with devices on a different network
在不同的网络中允许通讯。

to differentiate a Layer 2 frame from a Layer 3 packet
区分来自三层的包和二层的帧。

to establish a priority system to determine which device gets to transmit first
创立一个优先级系统以便确定哪个设备可以优先传输。

to allow communication between different devices on the same network
同一个网络中允许不同的设备通讯。

to allow detection of a remote device when its physical address is unknown
当物理地址未知的时候，允许远端设备检测。

QUESTION017
Refer to the exhibit. Based on the information given. Which switch will be elected root bridge and why?
如图所示，以图示信息，哪个交换机将会被选举为根桥，为什么？
Switch A ,because it has the lowest MAC address
交换机Ａ，因为它具有更低的ＭＡＣ地址。

Switch C,because it has the lowest priority
交换机Ｃ，因为它具有更低的优先级。

Switch B,because it has the highest MAC address
交换机Ｂ，因为它具有更高的ＭＡＣ地址。

Switch C,because it is the most centrally located switch 交换机Ｃ，因为它最处于交换机的中心。

Switch A,because it is the most centrally located switch 交换机Ａ，因为它最处于交换机的中心。

F.Switch D,because it has the highest priority
交换机Ｄ，因为它具有更高的优先级。

根桥的选举关键在于比较桥 ID（优先级+MAC 地址）大小，小者为根桥
QUESTION018
What value is primarily used to determine which port becomes the root port on each nonroot switch in a spanning-tree topology?
在非根桥的交换机上，如果要选择根端口，哪个值是最常用的？？
lowest port MAC address
更小的MAC地址。

port priority number and MAC address.
优先级号和MAC地址。

VTP revision number
VTP版本号。

highest port priority number.
更高的端口优先级号。

path cost
路径开销。

根端口的选择依据是到达根桥开销最小的端口，如果开销相同则找端口ID最小的端口
QUESTION019
Refer to the exhibit.Switch-1 needs to send data to a host with a MAC address
of 00b0.d056.efa4.What will Switch-1 do with this data?
如图所示，交换机１需要发送数据给一个ＭＡＣ地址为00b0.d056.efa4的主机，交换机１如何处理这个数据？
switch-1 will drop the data because it dose not have an entry for that MAC address
交换机１会终止这个数据因为它不在此MAC地址中。

switch-1 will flood the data out all of its port from which the data originated
交换机1发送给所有端口出了数据来源端口。

switch-1 will forward the data to its default gateway
交换机1会转发这个数据给默认网关。

switch-1 will send an ARP request out all its ports except the port from which the data
originated
交换机1发送一个ARP请求给所有端口出了数据来源端口。

ARP（IP←-----→ MAC ）
QUESTION020
What is the function of the command switchport trunk native vlan 999 on a switch?
在交换机上switchport trunk native vlan 999这个命令的作用是？
It designates VLAN 999 for untagged traffic.
没有标记的流量都打上 vlan999。

It blocks VLAN 999 traffic from passing on the trunk.
阻塞 VLAN999 从这个链路通过
It creates a VLAN 999 interface.
创立 vlan999 端口。

D.It designates VLAN 999 as the default for all unkown tagged traffic.
制定所有的未知标记帧为 VLAN999。

本征 vlan 都是不打标记的。

QUESTION021
Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network? (Choose two.)
哪两个协议是用于二层网络下的交换机和网桥，防止环路产生的协议？
802.1d
VTP
802.1q
STP
SAP
QUESTION022
Which switch would STP choose to become the root bridge in the selection process? 在 STP 选举过程中，哪个交换机将会成为根桥？
32768: 11-22-33-44-55-66
32768: 22-33-44-55-66-77
32769: 11-22-33-44-55-65
32769: 22-33-44-55-66-78
依据：交换机的 ID=优先级+MAC 地址
优先级必须是 4096 的整倍数+Vlan 号
QUESTION023
A switch is configured with all ports assigned to vlan 2 with full duplex FastEthernet to segment existing departmental traffic. What is the effect of adding switch ports to a new VLAN on the switch?
一个交换机的所有端口分配在 VLAN2 里，且使用的是全双工快速以太网。

现在把交换机的端口划分到新的 vlan 中会发生什么？
More collision domains will be created.
更多的冲突域将会创建。

IP address utilization will be more efficient.
IP 地址利用率将会更有效。

More bandwidth will be required than was needed previously.
比以前需要更多的带宽。

An additional broadcast domain will be created.
一个额外的广播域将会创建。

QUESTION024
What are three benefits of implementing vlans?(choose three)
实施 vlan 有哪三项好处？
A more efficient use of bandwidth can be achieved allowing many physical groups to use
the same network infrastructure
一个更有效利用带宽，这样可以允许更多的物理组使用同一个网络基础设施。

Broadcast storms can be mitigated by decreasing the number of broadcast domains,thus increasing their size.
广播风暴会被抑制，通过减小广播域的数量和增大广播域的大小。

A higher level of network security can be reached by separating sensitive data traffic from
other network traffic.
通过分割不同的网络数据从而达到更高的网络安全。

Port-based vlans increase switch-port use efficient,thanks to 802.1Q trunks
基于端口的 vlan 提高了交换机端口的使用效率，由于采用的是 802.1Q。

A more efficient use of bandwidth can be achieved allowing many logical networks to use
the same network infrastructure.
一个更有效利用带宽，这样可以允许更多的逻辑组组使用同一个网络基础设施。

Broadcast storms can be mitigated by increasing the number of broadcast domains,thus reducing their size.
广播风暴会被抑制，通过增大广播域的数量和减少广播域的大小。

VLANs make it easier for IT staff to configure new logical groups,because the vlans all belong to the same broadcast domain.
Vlan 使得管理员更简易的配置新的逻辑分组，因为这个 vlan 都是属于同一广播域中。

QUESTION025
Which IEEE standard protocol is initiated as a result of successful DTP completion in a switch over FastEthernet?
下列哪一个 IEEE 标准协议是一个快速以太网交换机中 DTP 过程的结果？
802.3ad
802.1w
802.1Q
802.1d
QUESTION026
Which of the following are benefits of VLANs? (Choose three.)
下列哪三项是 vlan 的好处？
They increase the size of collision domains.
他们增加了冲突域的大小。

They allow logical grouping of users by function.
他们允许根据使用者功能进行逻辑分组。

They can enhance network security.
他们能提高网络安全性。

They increase the size of broadcast domains while decreasing the number of collision domains.
他们增加了广播域的大小，并减少冲突域的数量。

They increase the number of broadcast domains while decreasing the size of the broadcast domains.
他们增加了广播域的数量并减少了广播域的大小。

F.They simplify switch administration.
他们简化了管理。

QUESTION027
Refer to the exhibit.A technician has installed SwithchB and needs to configure it for remote access from the management workstation connected SwitchA Which set of commands is required to accomplish this task?
如图所示，一个技术员已经安装好交换机 B 和配置它使能通过交换机 A 远程访问并且管理，那个命令是可以完成这个任务的？
SwitchB(config)#interface FastEthernet 0/1
SwitchB(config)#ip address 192.168.8.252 255.255.255.0
SwitchB(config)#no shutdown
SwitchB(config)#ip default-gateway 192.168.8.254
SwitchB(config)#interface vlan 1
SwitchB(config)#ip address 192.168.8.252 255.255.255.0
SwitchB(config)#no shutdown
SwitchB(config)#interface vlan 1 SwitchB(config)#ip
address 192.168.8.252 255.255.255.0
SwitchB(config)#ip default-gateway 192.168.8.254
255.255.255.0 SwitchB(config)#no shutdown
SwitchB(config)#ip default-network 192.168.8.254
SwitchB(config)#interface vlan 1
SwitchB(config)#ip address 192.168.8.252 255.255.255.0
SwitchB(config)#no shutdown
QUESTION028
In an Ethernet network, under what two scenarios can devices transmit? (Choose two.) 在以太网中，哪两种情况，设备可以传输数据？
when they receive a special token
当接受到一个特定的令牌时
when there is a carrier
当有一个载体的时候
when they detect no other devices are sending 没有检测到其他设备在发送数据
F.when the medium is idle
当传输介质为空闲状态
G.when the server grants access
当服务器允许访问的时候
载波侦听多路访问/冲突检测 (CSMA/CD)
QUESTION029
Which two states are the port states when RSTP has converged?(choose two)
当 RSTP 收敛的时候，端口会处于哪两种状态？
blocking
learning
discarding
forwarding
listening
QUESTION030
Which two commands can be used to verify a trunk link configuration status on a given cisco switch? (choose two)
那两个命令被用来在思科交换机上查看中继链路？
show interfaces interface
show interfaces trunk
show interfaces switchport
show ip interface brief
show interfaces vlan
QUESTION031
Which command enables RSTP on a switch?
在交换机上使用哪条命令开启 RSTP？
spanning-tree mode rapid-pvst
spanning-tree uplinkfast
spanning-tree backbonefast
spanning-tree mode mst
QUESTION032
Which of the following statements describe the network shown in the graphic? (Choose two.) 在下图表中，有关描述正确的是？
There are two broadcast domains in the network. 这个网络有两个广播域。

There are four broadcast domains in the network. 这个网络有４个广播域。

There are six broadcast domains in the network. 这个网络有６个广播域。

There are four collision domains in the network. 这个网络有４个冲突域。

There are five collision domains in the network. 这个网络有５个冲突域。

There are seven collision domains in the network. 这个网络有７个冲突域。

QUESTION033
Refer to the exhibit.
All switch ports are assigned to the correct VLANs, but none of the hosts connected to SwitchA can communicate with hosts in the same VLAN connected to SwitchB. Based on the output shown, what is the most likely problem?
如图所示，所有的交换机端口已经正确的配置在同一个 vlan 下。

但是交换机 A 上的所有主机都不能和处于同一 vlan 下的交换机 B 上的主机通信，根据输入，最有可能的问题出现在？
The access link needs to be configured in multiple VLANs.
Access 链路必须配置成多条 vlan。

The link between the switches is configured in the wrong VLAN.
两个交换机之间的链路配置在错误的 VLAN 中。

The link between the switches needs to be configured as a trunk.
两个交换机之中应该配置为 trunk 链路。

VTP is not configured to carry VLAN information between the switches.
VTP 是不能在两台交换机之间传输 vlan 的的。

Switch IP addresses must be configured in order for traffic to be forwarded between the switches
交换机 IP 必须配置以便在两台交换机之间交换机信息。

QUESTION034
Refer to the exhibit. Given the output shown from this Cisco Catalyst 2950, what is the most likely reason that interface FastEthernet 0/10 is not the root port for VLAN 2?
如下图所示为思科 Catalyst 2950 交换机的输入信息，端口 f0/10 没有成为 vlan2 的根端口的最有可能原因是什么？
This switch has more than one interface connected to the root network segment in VLAN 2. 这个交换机有超过１个的端口和 vlan2 的根桥直连。

This switch is running RSTP while the elected designated switch is running 802.1d Spanning Tree.
当指定交换机运行 802.1d 生成树的时候，这个交换机是运行 RSTP。

This switch interface has a higher path cost to the root bridge than another in the topology. 在这个拓扑中，此交换机比其他交换机到根桥具有更高的开销。

This switch has a lower bridge ID for VLAN 2 than the elected designated switch.
在 vlan2 中，这个交换机比指定交换机具有更低的桥 ID。

QUESTION035
Why will a switch never learn a broadcast address?
为什么交换机不会学习到广播地址？
Broadcast frames are never sent to swiches.
广播帧不能发送给交换机。

Broadcast addresses use an incorrect format for the switching table.
交换缓存表中的广播地址使用一个错误的格式。

A broadcast address will never be the source address of a frame.
一个广播地址不可能作为一个帧的原地址的。

Broadcasts only use network layer addressing.
广播只能使用在网络层。

A broadcast frame is never forwarded by a switch.
一个广播帧不会背交换机转发。

QUESTION 36
Refer to the exhibit. Why has this switch not been elected the root bridge for VLAN1?
如图所示，为什么这个交换机不能当选为 vlan1 的根桥？
It has more than one interface that is connected to the root network segment.
超过一个接口连接在根网络断中。

It is running RSTP while the elected root bridge is running 802.1d spanning tree.
当选举根桥的时候，这个交换机运行 RSTP，而根桥运行的是 802.1D 生成树协议。

It has a higher MAC address than the elected root bridge.
它比根桥具有一个更高的 MAC 地址。

It has a higher bridge ID than the elected root bridge.
它比根桥具有一个更高的桥 ID。

QUESTION037
Which two link protocols are used to carry multiple VLANs over a single link? (Choose two.) 下列那两个链路协议，被使用在单连璐中多 vlan 之间的信息传输？
A. VTP
B. 802.1q IEEE 标准
C. IGP
D. ISL 思科标准
E. 802.3u
QUESTION038
assuming the default switch configuration which vlan range can be added modified and removed on a cisco switch?
在一台采用默认配置的思科交换机上，能进行修改你和操作的 vlan 区间是？
2 through 1001 1 through 1001 1 through 1002
2 through 1005
QUESTION039
Which statement about vlan operation on cisco catalyst switches is true?
下列哪一项关于思科 catalyst 交换机中 vlan 的描述是正确的？
when a packet is received from an 802.1Q trunk,the vlan id can be determined from the source MAC address table.
当接受到一个来自 802.1Q 链路的数据包时，vlan 号是依靠源 MAC 地址表来确定的。

unkown unicast frames are retransmitted only to the ports that belong to the same vlan
未知的单播帧只在相同的 vlan 端口之间传播。

ports between switches should be configured in access mode so that vlans can span across the ports
交换机端口之间应该配置成 access 模式，以便 vlan 之间能穿过端口。

D. broadcast and multicast frames are retransmitted to ports that are configured on different vlan.
广播和多播帧，可以通过配置转发到不同的 vlan 当中。

QUESTION040
Refer to the topology shown in the exhibit. Which ports will be STP designated ports if all the links are operating at the same bandwidth? (Choose three.)
如下图所示拓扑中，所有端口都处在相同带宽中，那些端口将被 STP 作为指定端口？
Switch A - Fa0/0
Switch A - Fa0/1
Switch B - Fa0/0
Switch B - Fa0/1
Switch C - Fa0/0
Switch C - Fa0/1
QUESTION041
Refer to the exhibit. How should the FastEthernet0/1 port on the 2950 model switches that are
shown in the exhibit be configured to allow connectivity between all devices?
如图所示，相关配置如下，请问在 2950 的 f0/1 端口上应该如何配置才能让所有设备互通？
The ports only need to be connected by a crossover cable.
SwitchX(config)# interface FastEthernet 0/1
SwitchX(config-if)# switchport mode trunk
SwitchX(config)# interface FastEthernet 0/1
SwitchX(config-if)# switchport mode access
SwitchX(config-if)# switchport access vlan 1
SwitchX(config)# interface FastEthernet 0/1
SwitchX(config-if)# switchport mode trunk
SwitchX(config-if)# switchport trunk vlan 1
SwitchX(config-if)# switchport trunk vlan 10
SwitchX(config-if)# switchport trunk vlan 20
QUESTION042
Refer to the exhibit A frame on vlan 1 on switch s1 is sent to switch s2 when the frame is received on vlan 2,what causes this behavior?
如图所示，一个处于 vlan1 的交换机 S1 发送帧到交换机 S2 的 vlan2 中，会发生什么？
trunk mode mismatches
trunk 模式不匹配。

vlans that do not correspond to a unique IP subnet vlan 相当于一个独立的 IP 子网。

native vlan mismatches
本征 vlan 不匹配。

D.allowing only vlan 2 on the destination.
目的地只允许 vlan2.
QUESTION043
Which three statements about RSTP are true?(choose three) 下列关于 RSTP 描述中哪三项是正确的？
A.RSTP significantly reduces topology reconverging time after a link failure. 在一条链路失效的时候，RSTP 能有效的降低拓扑聚会时间。

RSTP expends the STP port roles by adding the alternate and backup roles.
RSTP 在 STP 的角色基础上增加了 alternate 和 bakup 端口。

RSTP port satates are blocking,discarding,learing,or forwarding.
RSTP 端口定义有：blocking、discarding、learing 和 forwarding。

RSTP also uses the STP proprsal-agreement sequence.
RSTP 也使用 STP proprsal-agreement 序列。

RSTP use the same timer-baseed process as STP on point-to-point links.
在点到点的链路中 RSTP 使用与 STP 一样的间隔时间。

RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.
在点到点的链路中，RSTP 比 STP 提供更快速度使端口进入转发状态。

QUESTION044
At which layer of the OSI model is RSTP used to prevent loops?
RSTP 使用 OSI 的哪一层来组织环路？
data link
数据链路层
network
网络层
physical
物理层
transport
传输层
QUESTION045
What dose a Layer 2 switch use to decide where to forward a received frame?
一个二层交换机如何确定收到的帧发哪里转发？
source MAC address
源ＭＡＣ地址。

source IP address
源 IP 地址。

source switch port
源端口。

destination IP address
目的 IP 地址。

destination port address 目的端口地址。

destination MAC address 目的 MAC 地址。

QUESTION046
Refer to the exhibit. Which statement is true?
如图所示，哪个描述是正确的？
The Fa0/11 role confirms that SwitchA is the root bridge for VLAN 20.
交换机Ａ的 f0/11 是 vlan20 的根桥角色。

VLAN 20 is running the Per VLAN Spanning Tree Protocol.
Vlan20 运行了 STP 协议。

The MAC address of the root bridge is 0017.596d.1580.
根桥的 MAC 地址是 0017.596d.1580.
SwitchA is not the root bridge, because not all of the interface roles are designated. 交换机 A 不是根桥，因为并非所有的端口都是指定端口。

QUESTION047
Which two benefits are provided by creating VLANs? (Choose two.)
建立 vlan 具有哪两项好处？
added security
增加安全性。

dedicated bandwidth
专用带宽。

provides segmentation
提供网络分段。

allows switches to route traffic between subinterfaces
允许交换机和路由器通过子接口联系。

contains collisions 包含冲突。

QUESTION048
Which command can be used from a PC to verify the connectivity between hosts that connect through a switch in the same LAN?
在同一个局域网内的一台交换机上，下列哪一个命令能用来检测主机之间的连通性？
ping address
tracert address
traceroute address
arp address
QUESTION049
Based on the network shown in the graphic which option contains the potential networking problem and protocol or setting that can to prevent the problem?
参照如图所示图表，哪一个选项可以包含了潜在的网络问题，以及协议或是能组阻止这个问题？
Routing loops, hold down timers
路由环路，抑制计时器。

Switching loops, split horizon
交换环路，水平分割。

Routing loops, split horizon
路由环路，水平分割。

Switching loops, VTP
交换环路，VTP。

Routing loops, STP
路由环路，STP。

F.Switching loops, STP 交换环路，STP。

QUESTION050
Refer to the exhibit. Which two statements are true about interVLAN routing in the topology that is shown in the exhibit? (Choose two.)
如下图所示，在此拓扑中，vlan 之间的路由描述，下列哪两项是正确的？
Host E and host F use the same IP gateway address.
主机 E 和主机 F 使用相同的网关 IP 地址。

Router1 and Switch2 should be connected via a crossover cable.
路由器 1 和交换机 2 应该通过交叉电脑通讯。

Router1 will not play a role in communications between host A and host D.
主机 A 和主机 D 之间的通讯，路由器 A 没有起作用。

The FastEthernet 0/0 interface on Router1 must be configured with subinterfaces.
R1 上的 F0/0 端口，必须配置子接口。

Router1 needs more LAN interfaces to accommodate the VLANs that are shown in the exhibit.
如图所示中，R1 需要更多的 LAN 接口，用来 vlan 之间的通讯。

The FastEthernet 0/0 interface on Router1 and Switch2 trunk ports must be configured using the same encapsulation type.
R1 的 f/0 和 SW2 之间的中继链路必须配置成使用相同封装类型。

QUESTION051
Which two of these are characteristics of the 802.1Q protocol?(choose two)
802.1Q 具有哪两项特征？
A.it is a layer 2 messaging protocol which maintains vlan configurations across network.
这是个二层信息协议，保证 vlan 配置能穿过网络。

it includes an 8-bit field which specifies the priority of a frame.
数据帧中包含了 8 个比特字节指定优先级。

it is used exclusively for tagging vlan frames and dose not address network reconvergence following switched network topology changes.
唯一的一个用于标记 vlan 数据帧和交换网络收敛的信息协议。

it modifies the 802.3 frame header,and thus requires that the FCS be recomputed.
修改了 802.3 帧的头部，并且会重新计算 FCS 的值。

it is a trunking protocol capable of carring untagged frames.
能传输未标记帧的 trunk 协议。

QUESTION052
Refer to the exhibit. Each of these four switches has been configured with a hostname, as well as being configured to run RSTP. No other configuration changes have been made. Which three of these show the correct RSTP port roles for the indicated switches and interfaces? (Choose three.) 如图所示，4 台交换机都配置了主机名，RSTP 也已经配置完毕。

没有其他配置改变。

下列那三项正确的表明了交换机的端口？
SwitchA, Fa0/2, designated
SwitchA, Fa0/1, root
SwitchB, Gi0/2, root
SwitchB, Gi0/1, designated
SwitchC, Fa0/2, root
SwitchD, Gi0/2, root
QUESTION053
Refer to the exhibit.The network administrator normally establishes a telnet session with the switch from host A.However,host A is unavailable.The administrator′s attempt to the switch from host B fails,but pings to the other two hosts are successful.what is the issue?。