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Prof.RuiSantosCruzrui.s.cruz@tecnico.ulisboa.pt
Networking:Inter-networking
MestradoemEngenhariaInformáDcaedeComputadoresMasterDegree(MSc)inInformaDonSystemsandComputerEngineering
Administração e Gestão de Infra-estruturas de IT IT Infrastructure Management and Administration
FieldTripVisit:
23rdOctober: TheNOKIAOpera3onsCenter BusAlameda-Alfragide-Alamedaat9.30-12.30(detailedinfowillbeannouncedinFenix)
Technologysessionswithinvitedspeakersfromindustry:
30thOctober: Oracle/SunHighPerformanceSolu3ons PresentedbyEng.JoséGonzalez
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DATECHANGE
OpenStandardsTheInternetSociety(ISOC)
TheInternetArchitectureBoard(IAB)
TheInternetEngineeringTaskForce(IETF)
InsDtuteofElectricalandElectronicsEngineers(IEEE)
TheInternaDonalOrganizaDonforStandards(ISO)TheElectronicIndustriesAlliance(EIA)
TheTelecommunicaDonsIndustryAssociaDon(TIA)
TheInternaDonalTelecommunicaDonsUnion–TelecommunicaDonsStandardizaDonSector(ITU-T)
TheInternetCorporaDonforAssignedNamesandNumbers(ICANN)
TheInternetAssignedNumbersAuthority(IANA)
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TheNetworkLayerTheNetworkLayer,orOSILayer3,providesservicestoallowenddevicestoexchangedataacrossthenetwork.Toaccomplishthisend-to-endtransport,thenetworklayerusesfourbasicprocesses:
Addressingenddevices
EncapsulaDon
RouDng
De-encapsulaDng
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NetworkLayerProtocolsCommonnetworklayerprotocolsinclude:
IPversion4(IPv4)
IPversion6(IPv6)
Legacynetworklayerprotocolsinclude:
NovellInternetworkPacketExchange(IPX)
AppleTalk
ConnecDonlessNetworkService(CLNS/DECNet)
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DataEncapsulaDon:CommunicaDngtheMessagesSegmenDngmessagebenefits:
DifferentconversaDonscanbeinterleaved
IncreasedreliabilityofnetworkcommunicaDons
SegmenDngmessagedisadvantage:
Increasedlevelofcomplexity
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AccessingLocalResources:MACandIPAddresses
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PC1 192.168.1.110
AA-AA-AA-AA-AA-AA
PC2 192.168.1.111
BB-BB-BB-BB-BB-BB
FTP Server 192.168.1.9
CC-CC-CC-CC-CC-CC
R1 192.168.1.1
11-11-11-11-11-11
ARP Request
S1 R1
IntroducingIPv6Increasedaddressspace
Improvedpackethandling
EliminatestheneedforNAT
Integratedsecurity
4billionIPv4addresses 4,000,000,000
340undecillionIPv6addresses340,000,000,000,000,000,000,000,000,000,000,000,000
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IPv6PacketHeader
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Version TrafficClass FlowLabel
PayloadLength NextHeader
HopLimit
SourceIPAddress
DestinationIPAddress
Byte1 Byte2 Byte3 Byte4
IPv4Addressing
IPv4addressesFour8-bitoctetsRepresentaDon:BinaryordoUeddecimalnotaDon
NetworkhostnameassignmentDynamic:usingDHCPStaDc
TradiDonalClassfulAddressing:A,B,C,D,EclassesClassD,EaddressesarereservedNetworkclassoftheNodeprovidesinformaDonaboutthesegmentofnetworkthenodebelongsto
38IPAddressing
IPv4
IPaddressinformaDonNetworkClassdeterminedbyfirstoctetClassA,ClassB,ClassC
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IPv4:ClassfulAddressing
First,simplestIPv4addressingtype
AdherestonetworkclassdisDncDons
RecognisesClassA,B,Caddresses
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IPv4:ClassfulAddressing
ClassD,ClassErarelyusedClassD:valuebetween224and230UsedforMulDcasDng
ClassE:valuebetween240and254Experimentaluse
Eightbitshave256combinaDonsNetworksuse1through2540:reservedasplaceholderExample:10.0.0.0
255:reservedforbroadcasttransmissionExample:255.255.255.255
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IPv4:ClassfulAddressing
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IPv4:SpecialAddresses
IPAddress MeaningAlloctetswith“0” ThisHost
networkIDoctectswith“0” HostID HostIDinthisnetwork
Alloctectswith“1”(255decimal) Broadcast
NetworkID hostIDoctetswith“1”(255decimal) BroadcastontheLAN
firstoctetwith“01111111”(127) hostIDusuallywith“0.0.1” Loopback
LoopbackaddressFirstoctetequals127(127.0.0.1)
LoopbacktestAkempDngtoconnecttoownmachinethroughtheinterfacePowerfultroubleshooDngtool
WindowsXP,Vista,Windows7,Windows8…ipconfigcommand
Unix,MacOSX,Linuxifconfigcommand
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IPv4:SpecialAddresses
IdenDfieseverydeviceonTCP/IP-basednetwork
32-bitnumber(netmask)IdenDfiesdevice’ssubnetCombineswithdeviceIPaddressInformsnetworkaboutsegment,networkwheredeviceakached
Fouroctets(32bits)ExpressedinbinaryordokeddecimalnotaDon
AssignedthesamewayIPaddresses:Manually,orautomaDcally(viaDHCP)
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IPv4:SubnetMask
SubneongSubdividingnetworksingleclassintomulDple,smallerlogicalnetworks(segments)ControlnetworktrafficMakebestuseoflimitednumberofIPaddresses
Subnetmaskvariesdependingonsubneong
Nonsubnekednetworksusedefaults
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IPv4:Subneong
IdenDfieshownetworksubdivided
IndicateswherenetworkinformaDonlocated
Subnetmaskbits1:correspondingIPv4addressbitscontainnetworkinformaDon0:correspondingIPv4addressbitscontainhostinformaDon
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IPv4:Subneong
ANDingCombiningbitsBitvalueof1plusanotherbitvalueof1resultsin1Bitvalueof0plusanyotherbitresultsin0ANDinglogic1:“true”,0:“false
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IPv4
IPv4Addressing
ANDingexampleAddress’sfourthoctetAnycombinaDonof1sand0sResultsinnetworkIDfourthoctetof0s
48IPAddressing
IPv4
SubneXngbreaksclassfulIPv4addressingrulesIPaddressbitsrepresenDnghostinformaDonchangetorepresentnetworkinformaDonReduceusablehostaddressespersubnetHosts,subnetsavailableaqersubneongrelatedtohostinformaDonbitsborrowed
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IPv4
Formula:2n−2=Yn:numberofsubnetmaskbitsneededtoswitchFrom0to1
Y:numberofresulDngsubnets
ExampleClassCnetworkNetworkID:199.34.89.0divideintosixsubnets
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IPv4:ClassCnetworkfor6subnetsexample
AlsocalledclasslessrouDngorsuperneXng
NotexclusiveofsubneongProvidesaddiDonalwaysofarrangingnetworkandhostinformaDoninanIPaddressConvenDonalnetworkclassdisDncDonsdonotexist
Example:subdividingClassCnetworkintosixsubnetsof30addressablehostseach
SupernetSubnetcreatedbymovingsubnetboundaryleq
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IPv4:CIDR(ClasslessInterdomainRouDng)
CIDRnotaDon(orslashnotaDon)ShorthanddenoDngsubnetboundaryposiDonForm:NetworkIDfollowedbyforwardslash(/),followedbynumberofbitsusedforextendednetworkprefix
CIDRblockForwardslash,plusnumberofbitsusedforextendednetworkprefix
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IPv4:CIDR
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IPv4:SuperneongThereareonlythreebasicrulesforsupernetcreaDon:
Numericcon3guity:
NetworkaddressesmustbenumberedconsecuDvely,i.e.,addressblocksarenumericallyadjacent
Evendivisibility:
NetworkaddressesendonthecorrectbitboundariestopreservethesymmetryofaCIDRizedaddressspace
Evendivisibilityisdeterminedbydividingtheoctetthatcontainstheboundarybetweenhostandnetworkaddressfieldsbythenumberofnetworkstosupernettogether
Singleinterface:
Thetwoormorenetworkblocksthataretobeaggregatedmustbeconnectedtothesameinterface
Example:classCrangeofIPv4addressessharingnetworkID192.168.64.32/26Networks192.168.64.32/27and192.168.64.64/27aresuperneUedtogetherandadver3sedas192.168.64.32/26.Thetwo/27networkblockscanbothbereferencedbythesame26-bitnetworkaddress
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IPv4:Superneong
Before:twoseparatenetworkinterfaces
A\ersuperneXng:singlenetworkinterface
IPv6ReplacingIPv4(gradually)
IPv6supportMostnewapplicaDons,servers,networkdevices
DelayinimplementaDonCostofupgradinginfrastructure
IPv6advantagesMoreefficientheader,bekersecurity,bekerprioriDzaDonprovisions,automaDcIPaddressconfiguraDonBillionsofaddiDonalIPaddresses
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IPv6
DifferencebetweenIPv4andIPv6addressesSizeIPv4:32bitsIPv6:eight16-bitfields(128bits)IPv6:296(4billionDmes4billionDmes4billion)availableIPaddresses
Representa3onIPv4:binarynumbersseparatedbyperiodIPv6:hexadecimalnumbersseparatedbycolon:2031:0000:130F:0000:0000:09C0:876A:130BIPv6shorthand:“::”anynumberofmulDple,zero-valuefieldsIPv6loopbackaddressis0:0:0:0:0:0:0:1Abbreviatedloopbackaddress::1
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IPv6
PrefixRepresentaDon:justlikeIPv4CIDR,akachtheprefixlength:
LikeIPv4address:198.10.0.0/16
IPv6addressisrepresentedinthesameway:2001:db8:12::/40
AddressTypesare:
Unicast:OnetoOne(Global,UniqueLocal,Linklocal)
Anycast:OnetoNearest(AllocatedfromUnicast)
MulDcast:OnetoMany
AsingleinterfacemaybeassignedmulDpleIPv6addressesofanytype(unicast,anycast,mulDcast)
NoBroadcastAddress→UseMulDcast
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IPv6
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IPv6:GlobalUnicastAddressingAddressblockdelegatedbyIETFtoIANA:FordistribuDontotheRIRsandontotheusersofthepublicInternet
GlobalUnicastAddressblockis2000::/3 Thisis1/8thoftheenDreavailableIPv6addressspace
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IPv6:UniqueLocalAddressingUnique-LocalAddresses(ULAs)areNOTroutableontheInternet
ULAsareusedfor:
Isolatenetworks
LocalcommunicaDons&inter-siteVPNs
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IPv6:LinkLocalAddressingLink-LocalAddressesUsedFor:CommunicaDonbetweentwoIPv6device(likeARPbutatLayer3)
Next-HopcalculaDoninRouDngProtocols
AutomaDcallyassignedbyRouterassoonasIPv6isenabled
MandatoryAddress
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IPv6:MulDcastAddressingMulDcastAddressesUsedFor:
OnetomanycommunicaDon
2ndoctetreservedforLifeDmeandScope
RemainderofaddressrepresentstheGroupID
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