You have a class C network, and you need to design it for 5 usable subnets with each subnet handling a minimum of 18 hosts each. Which of the following network masks should you use?A．225.225.224.0.B．225.225.240.0.C．225.225.255.0.D．255.255.255.224E．225.225
题目
You have a class C network, and you need to design it for 5 usable subnets with each subnet handling a minimum of 18 hosts each. Which of the following network masks should you use?
A．225.225.224.0.
B．225.225.240.0.
C．225.225.255.0.
D．255.255.255.224
E．225.225.255.240
相似考题
参考答案和解析
正确答案：D
解析：Explanation:ThedefaultsubnetmaskforclassCnetworkis255.255.255.0.Ifonehastocreate5subnets,then3bitsarerequired.With3bitswecancreate8subnets.Theremaining5bitsareusedforHosts.Onecancreate30hostsusing5bitsinhostfield.Thismatcheswiththerequirement.IncorrectAnswers:A,B:ThisisanillegalsubnetmaskforaclassCnetwork,asthethirdoctetcannotbedividedwhenusingaclassCnetwork.C:ThisisthedefaultsubnetmaskforaclassCnetwork.Itprovidesforonenetwork,with254usablehostIPaddresses.E:Thissubnetmaskwillprovidefor14separatenetworkswith14hostseach.Thisdoesnotmeettherequirementofaminimumof18hosts.
解析：Explanation:ThedefaultsubnetmaskforclassCnetworkis255.255.255.0.Ifonehastocreate5subnets,then3bitsarerequired.With3bitswecancreate8subnets.Theremaining5bitsareusedforHosts.Onecancreate30hostsusing5bitsinhostfield.Thismatcheswiththerequirement.IncorrectAnswers:A,B:ThisisanillegalsubnetmaskforaclassCnetwork,asthethirdoctetcannotbedividedwhenusingaclassCnetwork.C:ThisisthedefaultsubnetmaskforaclassCnetwork.Itprovidesforonenetwork,with254usablehostIPaddresses.E:Thissubnetmaskwillprovidefor14separatenetworkswith14hostseach.Thisdoesnotmeettherequirementofaminimumof18hosts.