正确答案: B

1-99

题目：标准访问控制列表的数字标识范围是（）。

解析：B

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举一反三的答案和解析：

[单选题]Which one of the following characteristics is true regarding the use of hubs and switches?

Switches increase the number of collision domains in the network.

解析：解析：Explanation:Switchesincreasesthenumberofcollisionsdomainsinthenetwork.SwitchesthatareconfiguredwithVLANswillreducethesizeofthecollisiondomainsbyincreasingthenumberofcollisiondomainsinanetwork,butmakingthemsmallerthanthatofonebig,flatnetwork.IncorrectAnswers:A.SwitchesarecapableofVLANconfigurations,buthubsarenot.B.Hubsaregenerallytheleastcostlymethodpossibletoconnectmultipledevicestogetherinanetwork.C.Switchesforwardbroadcastsandmulticasts,bydefault,toallportswithinthesameVLAN.Onlyroutersblockallbroadcasttrafficbydefault.D.Switchesandhubscanbeequallyefficientinprocessingframes,intheory.Inpractice,switchesaregenerallymoreefficientastheyusuallyhavemoreCPUandmemoryallocatedtothem,andaregenerallymuchmoreexpensivethanasimplehub.

[单选题]路由器上的命令“show version”的功能是（）

显示版本信息

[单选题]网关的功能（）

不同网段通信

[单选题]OSPF骨干区的区域编号为（）

0.0.0.0

[单选题]下列命令中，无法正确执行的是（）

Router(config)show run

[单选题]Your network uses the172.12.0.0 class B address. You need to support 459 hosts per subnet, while accommodating the maximum number of subnets. Which mask would you use?

255.255.254.0.

解析：解析：Explanation:Toobtain459hoststhenumberofhostbitswillbe9.Thiscansupportamaximumof510hosts.Tokeep9bitsforhostsmeansthelastbitinthe3rdoctetwillbe0.Thisgives255.255.254.0asthesubnetmask.