首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
计算机
You’ve been assigned a single Class C address. From this, you need 8 subnets, and your subnet mask is 255.255.255.224. Which one
You’ve been assigned a single Class C address. From this, you need 8 subnets, and your subnet mask is 255.255.255.224. Which one
admin
2009-05-19
82
问题
You’ve been assigned a single Class C address. From this, you need 8 subnets, and your subnet mask is 255.255.255.224. Which one of the following configuration commands would you have to use before you begin?
A. Router(config)# ip classless
B. Router(config)# ip subnet-zero
C. Router(config)# ip version 6
D. Router(config)# no ip classful
E. Router(config)# ip unnumbered
F. Router(config)# ip all-nets
选项
答案
B
解析
Explanation: To get 8 subnets from a class C address, and a mask of 255.255.255.224 use the reserved subnet space. To do this, you need the command ’ip subnet-zero.’ This will allow the router to use the very first subnet, which is normally reserved and unused as the network address.
Prior to Cisco IOS? Software Release 12.0, Cisco routers, by default, did not allow an IP address belonging to subnet zero to be configured on an interface. However, if a network engineer working with a Cisco IOS software release older than 12.0 finds it safe to use subnet zero, the ip subnet-zero command in the global configuration mode can be used to overcome this restriction.
As of Cisco IOS Software Release 12.0, Cisco routers now have ip subnet-zero enabled by default, but if the network engineer feels that it is unsafe to use subnet zero, the no ip subnet-zero command can be used to restrict the use of subnet zero addresses.
In versions prior to Cisco IOS Software Release 8.3, the service subnet-zero command was used.
It should be noted that even though it was discouraged, the entire address space including subnet zero and the all-ones subnet have always been usable. The use of the all-ones subnet was explicitly allowed and the use of subnet zero is explicitly allowed since Cisco IOS Software Release 12.0. Even prior to Cisco IOS Software Release 12.0, subnet zero could be used by entering the ip subnet-zero global configuration command.
On the issue of using subnet zero and the all-ones subnet, RFC 1878 states, "This practice (of excluding all-zeros and all-ones subnets) is obsolete. Modern software will be able to utilize all definable networks." Today, the use of subnet zero and the all-ones subnet is generally accepted and most vendors support their use. However, on certain networks, particularly the ones using legacy software, the use of subnet zero and the all-ones subnet can lead to problems.
转载请注明原文地址:https://kaotiyun.com/show/I0hZ777K
本试题收录于:
思科640802题库思科认证分类
0
思科640802
思科认证
相关试题推荐
BendItLikeBeckhamiswelcome.ItisthestoryofaBritishgirlnamedJesswhomustchoosebetweenthetraditionsofherfami
HeatIsKillerExtremelyhotweatheriscommoninmanypartsoftheworld.Althoughhotweatherjustmakesmostpeoplefeel
Writeanessayof160-200wordsbasedonthefollowingdrawing.Inyouressay,youshould1)describethedrawingbriefly,
Writeanessayof160-200wordsbasedonthefollowingdrawing.Inyouressay,youshould1.describethedrawingbriefly,2.e
SupposeyouphonedyourfriendMaryseveraltimesyesterdaybutshedidn’tansweryourcallatall.Writeheranemailto1
TodayweliveinaworldwhereGPSsystems,digitalmaps,andothernavigationappsareavailableonoursmartphones.【B1】______
Parentsarenottheonlyonesresponsiblefortheirchildren.Oursocialresponsibilityisatitsgreatestwhenparentsareunab
Inthisyear’sStateoftheUnionaddress,PresidentObamaoutlinedaplantograduallyraisetheminimumwagefrom$7.25to$9/
YournetworkconsistsofnumerousdomainswithinaLAN,plusoneremotelocationthatisconfiguredasanotherdomainwithinthe
AsaCCNAcandidate,youmustknowthevariouslayersoftheOSImodel.AtwhichlayersoftheOSIModeldoWideAreaNetworkso
随机试题
起到封闭管路或隔断管路作用的是()法兰。
护理咯血患者的关键措施是
施工进度计划应当由()审查。
出票人在票据上的记载事项不得有票据法和支付结算办法规定事项以外和其他事项。()
关于我国三家期货交易所结算制度说法,正确的是()。
某市乙企业(居民企业)为增值税一般纳税人,2015年度取得销售收入7800万元,销售成本为4600万元,会计利润为800万元。2015年,乙企业其他相关财务资料如下:(1)在管理费用中,发生业务招待费70万元,支付给其他企业管理费20万元,新
脂溶性维生素
在结构化设计方法中生成的结构图(SC)中,带有箭头的连线表示()。
Whotobelieve?NokiaorEricsson?IBMorSunMicrosystems?MicrosoftorSiebel?Rarelyhavethefortunesoftechnologycompanie
IthinkFrenchgrammarismuch(difficult)______tolearnthanEnglishgrammar.
最新回复
(
0
)