对于ip地址范围以及划分和子网掩码的关系是怎样

对于IP地址范围以及子网划分，IP地址和子网掩码的关系是怎样的 组态事项6GK7343-1EX30-0XE0-CIDRw wwwPLCworldCPU319-3PN/DP-CIDRCPU414-3PN/DP-CIDRCPU416-3PN/DPCPU416F-3PN/DP-CIDRTCP/IP协议的工业以太网CP模板CPU，可以STEP7硬件组态中IP地址和相关的子IP地址和相应的子网掩码可以在CPCPU的以太网接口的属性窗口中设置。在硬件组态插入CP模板或CPU后，在它们的属性窗口会得到下面的默认设置(图.01)。IP地址子网掩码w IP地址和子网掩码分类关系类表示类的位子网掩码网络节点A0.x.x.x13B128.0.x.x22C31D&--A网地址。所以A类网络由以下的子网掩码定义：=11111111000000000000000000000000。IP地址的后3个字节(24位)用于识别网络上的主机。A类网络按照下面方法计算节点个数：22416777216图02AB类网络BIP1-0-...开始，IP128.0.x.x191.255.x.xB类网络，头两个字16IPB类网络由以下的子网掩码定义：11111111111111110000000000000000IP2个字节(16位)用于识别网络上的主机。B类网络按照下面方法计算子网个数：B类网络按照下面方法计算节点个数：21665536w图03BC类网络

wwwPLCworld字节，也就是头24位对应IP地址的子网地址。所以C类网络由以下的子网掩码定义：=11111111111111111111111100000000。IP1个字节(8位)用于识别224-32212097152(CIP1-1-0开始)B类网络按照下面方法计算节点个数：28256图04CD类子网对于子网部分，A类网络的子网数是大大少于C类网络的。127IP地址仅用于计算机的内部测试。---划分子网100000000000000000000000)子网掩码后的第一位为相同的值(这里"0")。ww 仅地址到86.255.255 在子网掩码后的第一位为相同的值(这里"1")结论超网11000000(11111111.11111111.10110000.000054(11111111.11111111.10110011.1111要求"超网的使用要求网络中有支持"无类别域间路由CIDR)功能的模块。STEP7STEP(见图05"STEP7错误信息")。11111111000001010000000000000000这种形式出现。这里用很多错误，强烈建议不使用这样的子网掩码。STEP7在组态CP卡以太网接口属性中不允许设置这样w wwwPLCworld图05STEP7ww.91HMI.co目号Scrolldownfor

wwwPLCworldcn:2009-01-WhatWhatistheconnectionbetweensubnetmasksandIPaddressesintheIPaddressarea,alsowithregardtosubnetting?WithCIDR,thereisnofixedassignmentofanIPaddresstoanetworkclassandpossiblesubnettinginothernetworksorsupernettingofseveralnetworksinaclass.ThereisonlyonenetworkmaskthatsplitstheIPaddressintoanetworkpartandahostpart.TheCIDRfunction(classlessinter routing)thusincludessubnettingandsupernetting.ThefollowinglistshowsyouwhichIndustrialEthernetCPssupportthetwofunctionsofsubnettingandsupernetting:6GK7343-1EX11-0XE0-doesnotsupporttheCIDR6GK7343-1EX20-0XE0-supportstheCIDR6GK7343-1EX21-0XE0-supportstheCIDRfunctionfromfirmwareV1.26GK7343-1EX30-0XE0-supportstheCIDR6GK7343-1GX20-0XE0-doesnotsupporttheCIDR6GK7343-1GX21-0XE0-supportstheCIDRfunctionfromfirmwareV1.16GK7343-1GX30-0XE0-supportstheCIDR6GK7343-1CX00-0XE0-doesnotsupporttheCIDR6GK7343-1CX10-0XE0-supportstheCIDR6GK7443-1EX10-0XE0-doesnotsupporttheCIDR6GK7443-1EX11-0XE0-doesnotsupporttheCIDR6GK7443-1EX20-0XE0-supportstheCIDR6GK7443-1EX40-0XE0-supportstheCIDRfunctionfromfirmwareV2.46GK7443-1EX41-0XE0-supportstheCIDR6GK7443-1GX20-0XE0-supportstheCIDRandfortheS7-300andS7-400CPUswithintegratedPROFINETCPU315-2PN/DPandCPU315F-2PN/DP-supportCIDRfromfirmwareV2.3CPU317-2PN/DPandCPU317F-2PN/DP-supportCIDRfromfirmwareV2.3CPU319-3PN/DP-supportsCPU414-3PN/DP-supportsCPU416-3PN/DPandCPU416F-3PN/DP-supportThefollowingIndustrialEthernetPCmodulessupportthefunctionsofsubnettingandCP1616fromCP1604fromItisonlypossibletoconfigurethe"Subnetting"functionfortheremainingIndustrialEthernetPCmoduleslikeIEgeneral,CP1613(A2),CP1623,CP1612andCP1512.Itisnotpossibletoconfigurethe"Supernetting"functioninSTEP7/NCMPCforthesemodules.ThisispreventedinSTEP7/NCMPCbyanerrormessage(seeFig.05).InthesemodulesthatsupporttheTCP/IPprotocolitispossibletosetboththeIPaddressandtheassociatedsubnetmaskinthehardwareconfigurationofSTEP7.TheIPaddressandassociatedsubnetmaskareenteredinthePropertieswindowoftheCP'sorCPU'sEthernetinterface.AfterinsertingtheIndustrialEthernetCPorCPUwithintegratedPNinterfaceinthehardwareconfiguration,youareofferedthefollowingdefaultsettings(seeFig.01)inthePropertieswindowoftheCP'sorCPU'sEthernetinterface.IPaddress: Subnetmask:

wwwPLCworldFig.01:PropertieswindowofaCP'sEthernetIfyouwishtochangethesedefaultsettingsfortheIPaddressandsubnetmask,youneedinformationontheconnectionbetweenclassesofIPaddressesandsubnetmasks.ThefollowingmakescleartheconnectionbetweenclassesofIPaddressesandsubnetmasks.ConnectionbetweenclassoftheIPaddressandsubnetInprinciplethereare5classesofIPaddresses.ThesearetheclassesAtoE.Eachclasshasitsownsubnetmask.Theconnectionsaregiveninthetablebelow.ClassIPnetworkaddressSubnetNetworkA0.x.x.x-13B128.0.x.x-22C192.0.0.x-31D&--ClassAIPaddressesfromClassAbeginwiththebitsequence0-...,e.g.theIPaddressrangelies0.x.x.xandThesubnetmaskidentifiestherangethatincludestheaddressinformationforidentifyingthesubnet.InClassAnetworksthefirstbyte,thatistosaythefirst8bitscorrespondtotheIPaddressofthesubnetaddress.ThusClassAnetworksaredefinedbythefollowingsubnetmask:=11111111000000000000000000000000.Thelastthreebytes(24bits)oftheIPaddressidentifyanodeinthissubnet.ThetotalnumberofClassAnetworkscanbecalculatedas28-1-2=27-2=126networks(sincetheIPaddressalwaysbeginswiththebitsequence0-...,andarenotpermitted)ThenumberofcomputersinaClassAnetworkcanbecalculatedasw wwwPLCworld224-2=16777214computers(x.0.0.0->networkaddressandx.255.255.255->broadcastaddressarenotpermitted)Fig.02:ClassAClassBIPaddressesfromClassBbeginwiththebitsequence1-0-...andtheaddressrangelies128.0.x.xand191.255.x.x.InClassBnetworksthefirsttwobytes,thatistosaythefirst16bitscorrespondtotheIPaddressofthesubnetaddress.ThusClassBnetworksaredefinedbythefollowingsubnetmask:=11111111111111110000000000000000.Thelasttwobytes(16bits)identifyanodeinthissubnet.ThetotalnumberofClassBnetworkscanbecalculatedas216-2=214=16384networks(sincetheIPaddressalwaysbeginswiththebitsequence1-ThenumberofcomputersinaClassBnetworkcanbecalculatedas216-2=65534computers(x.x.0.0->networkaddressandx.x.255.255->broadcastaddressarenotpermitted)Fig.03:ClassBClassCIPaddressesfromClassCbeginwiththebitsequence1-1-0...andtheaddressrangelies192.0.0.xand223.255.255.x.InClassCnetworksthefirstthreebytes,thatistosaythefirst24bitscorrespondtotheIPaddressofthesubnetaddress.ThusClassCnetworksaredefinedbythefollowingsubnetmask:=11111111111111111111111100000000.Thelastbyte(8bits)identifiesanodeinthissubnet.ThetotalnumberofClassCnetworkscanbecalculatedas224-3=221=2097152networks(sincetheIPaddressalwaysbeginswiththebitsequenceThenumberofcomputersinaClassCnetworkcanbecalculatedas28-2=254computers(x.x.x.0->networkaddressandx.x.x.255->broadcastaddressarenotpermitted)w wwwPLCworldFig.04:ClassCClassDTheclassDsubnetworkconsistsofspecialaddressesthatareusedformulticastaddressing.ThissplittingupofIPaddressesinnetworkshareandcomputershareleadstothefollowingAClassAnetworkislargerthanaClassCnetwork,becausethereisamuchgreateraddressareaavailableforaddressingthecomputers.TherearemuchlessClassAnetworksthanClassCnetworksbecausetheaddressareaofthesubnetsismuchsmaller.TheClassAnetworkaddress127.x.x.xis fortheLoopbackfunctionofallcomputers,i.e.:allIPaddressesthathavethevalue127inthefirstbytemayonlybeusedforinternaltestsofcomputers.The255valuesare asbroadcastaddresses.Thus,forexample,theaddress55isabroadcastaddresstoallcomputersintheClassBnetwork.Thefollowingrangesare forprivatenetworks.AllIPaddressesintheserangesarenotroutedintheInternet.---Untilnow,theconnectionbetweentheclassoftheIPaddressandsubnetmaskhasbeenexined.Furthermore,itispossibletoextendthesubnetmaskwiththeso-called"subnetting"procedure.SubnettingcanbeimplementedinaClassAnetwork,forexample.ItispossibletodividethecomputersofthisClassAnetworkintofurtherlogicalunits(subnets).WewillobservetheClassAnetwork86.x.x.xasanexample.ThesubnetmaskofthisClassAnetworkis(11111111000000000000000000000000).Theaddressareacanbedividedfurtherintologicalsubnetsextendingthesubnetmaskby1bit.Thesubnetmaskisthen(111111111000000000000000ThismeansthefollowingforOnlytheaddressesto54cancommunicatedirectlywitheachi.e.withoutrouter,becausethesecomputershavethesamevalue(inthiscase"0")inthefirstbitafterthesubnetmask.Onlytheaddressesto54cancommunicatedirectlywitheachi.e.withoutrouter,becausethesecomputershavethesamevalue(inthiscase"1")inthefirstbitafterthesubnetmask.TheaddressareaofthecomputersinthisClassAnetworkhasbeendividedintotwoByextendingthesubnetmaskyoucandividetheaddressareaofthecomputersintomorelogicalunits(subnets).Theaddressareahasbeendividedintotwosubnetsintheexample.Byaddingmorebitsyoucanquicklymultiplythenumberofsubnets.Youcanextendasubnetasyouwish.Supernettingisthegroutogetherofmultiplenetworkswithpartiallythesamenetworkshareinonesingleroute.Theunderlyingtechnologyistheoppositetosubnettingandinprinciplemeans.91HMI.ocedurrlshareofanetworkclassisincreased.Thusthenetworkshareofthisnetworkclassisdecreased.WewillobservetheClassCnetworkasanexample.ThesubnetmaskofthisClassCnetworkis(11111111111111111111111100000000).Now2bitsareaddedtohostshare.Thesubnetmaskisthen(1111111111111111111111000000ThelowestIPaddressofthenetworktobeassignedis(11111111.11111111.10110000.00000001)ThehighestIPaddressofthenetworktobeassignedis54(11111111.11111111.10110011.111