Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how...

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CSE 461 University of Washington 1 Topic • Filling in the gaps we need to make for IP forwarding work in pracBce – GeDng IP addresses (DHCP) » – Mapping IP to link addresses (ARP) » What link layer address do I use? What’s my IP?

Transcript of Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how...

Page 1: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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Topic•  FillinginthegapsweneedtomakeforIPforwardingworkinpracBce–  GeDngIPaddresses(DHCP)»– MappingIPtolinkaddresses(ARP)»

WhatlinklayeraddressdoIuse?

What’smyIP?

Page 2: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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GeDngIPAddresses•  Problem:

–  AnodewakesupforthefirstBme…– WhatisitsIPaddress?What’stheIPaddressofitsrouter?Etc.

–  AtleastEthernetaddressisonNIC

Hey,whereamI?

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GeDngIPAddresses(2)1.  ManualconfiguraBon(olddays)

–  Can’tbefactoryset,dependsonuse2.  AprotocolforautomaBcally

configuringaddresses(DHCP)»–  ShiXsburdenfromuserstoITfolk

UseA.B.C.DWhat’smyIP?

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DHCP•  DHCP(DynamicHostConfiguraBon

Protocol),from1993,widelyused

•  ItleasesIPaddresstonodes•  Providesotherparameterstoo

–  Networkprefix–  Addressoflocalrouter–  DNSserver,Bmeserver,etc.

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DHCPProtocolStack•  DHCPisaclient-serverapplicaBon

–  UsesUDPports67,68

Ethernet

IP

UDP

DHCP

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DHCPAddressing•  Bootstrapissue:

–  HowdoesnodesendamessagetoDHCPserverbeforeitisconfigured?

•  Answer:–  Nodesendsbroadcastmessagesthatdeliveredtoallnodesonthenetwork

–  Broadcastaddressisall1s–  IP(32bit):255.255.255.255–  Ethernet(48bit):ff:ff:ff:ff:ff:ff

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DHCPMessagesClient Server

Onelink

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DHCPMessages(2)Client Server

DISCOVER

REQUEST

OFFER

ACK

Broadcast

Page 9: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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DHCPMessages(3)•  TorenewanexisBnglease,anabbreviatedsequenceisused:–  REQUEST,followedbyACK

•  Protocolalsosupportsreplicatedserversforreliability

Page 10: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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SendinganIPPacket•  Problem:

–  AnodeneedsLinklayeraddressestosendaframeoverthelocallink

–  HowdoesitgetthedesBnaBonlinkaddressfromadesBnaBonIPaddress?

Uhoh… MyIPis1.2.3.4

Page 11: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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ARP(AddressResoluBonProtocol)•  NodeusestomapalocalIPaddresstoitsLinklayeraddresses

SourceEthernet

Dest.Ethernet

SourceIP

Dest.IP Payload…

Linklayer

FromDHCP

FromNIC

FromARP

Page 12: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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ARPProtocolStack•  ARPsitsrightontopoflinklayer

–  Noservers,justasksnodewithtargetIPtoidenBfyitself

–  Usesbroadcasttoreachallnodes

Ethernet

ARP

Page 13: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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ARPMessagesNode Target

Onelink

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ARPMessages(2)Node Target

REQUEST BroadcastWhohasIP1.2.3.4?

REPLY

Idoat1:2:3:4:5:6

Page 15: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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DiscoveryProtocols•  Helpnodesfindeachother

– Therearemoreofthem!•  E.g.,zeroconf,Bonjour

•  OXeninvolvebroadcast– Sincenodesaren’tintroduced– Veryhandyglue

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OtherAspectsofForwarding•  It’snotallaboutaddresses…

Payload(e.g.,TCPsegment)

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OtherAspects(2)•  DecrementTTLvalue

–  Protectsagainstloops•  Checksheaderchecksum

–  Toaddreliability•  Fragmentlargepackets

–  Splittofititonnextlink•  SendcongesBonsignals

–  WarnshostsofcongesBon•  Generateserrormessages

–  Tohelpmangenetwork•  HandlevariousopBons

Cominglater

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Bigpacket

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Topic•  Howdoweconnectnetworkswithdifferentmaximumpacketsizes?–  Needtosplituppackets,ordiscoverthelargestsizetouse

It’stoobig!Takethat

Page 19: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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PacketSizeProblem•  Differentnetworkshavedifferentmaximumpacketsizes–  OrMTU(MaximumTransmissionUnit)–  E.g.,Ethernet1.5K,WiFi2.3K

•  Preferlargepacketsforefficiency–  Butwhatsizeistoolarge?–  Difficultbecausenodedoesnotknowcompletenetworkpath

Page 20: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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PacketSizeSoluBons•  FragmentaBon(now)

–  Splituplargepacketsinthenetworkiftheyaretoobigtosend

–  Classicmethod,dated

•  Discovery(next)–  Findthelargestpacketthatfitsonthenetworkpathanduseit

–  IPusestodayinsteadoffragmentaBon

Page 21: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

IPv4FragmentaBon•  Routersfragmentpacketsthataretoolargetoforward•  Receivinghostreassemblestoreduceloadonrouters

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Fragment! Reassemble!

Fitsonfirstlink

Page 22: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

IPv4FragmentaBonFields•  Headerfieldsusedtohandlepacketsizedifferences

–  IdenBficaBon,Fragmentoffset,MF/DFcontrolbits

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Payload(e.g.,TCPsegment)

Page 23: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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IPv4FragmentaBonProcedure•  Routerssplitapacketthatistoolarge:

–  Typicallybreakintolargepieces–  CopyIPheadertopieces–  Adjustlengthonpieces–  SetoffsettoindicateposiBon–  SetMF(MoreFragments)onallpiecesexceptlast

•  Receivinghostsreassemblesthepieces:–  IdenBficaBonfieldlinkspiecestogether,MFtellsreceiverwhenithasallpieces

Page 24: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

IPv4FragmentaBon(2)

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ID=0x12efDataLen=2300Offset=0MF=0

ID=DataLen=Offset=MF=

ID=DataLen=Offset=MF=

BeforeMTU=2300

AXerMTU=1500

(Ignorelengthofheaders)

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IPv4FragmentaBon(3)

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ID=0x12efDataLen=2300Offset=0MF=0

ID=0x12efDataLen=1500Offset=0MF=1

ID=0x12efDataLen=800Offset=1500MF=0

BeforeMTU=2300

AXerMTU=1500

Page 26: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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IPv4FragmentaBon(4)•  Itworks!

–  AllowsrepeatedfragmentaBon

•  ButfragmentaBonisundesirable– Moreworkforrouters,hosts–  Tendstomagnifylossrate–  SecurityvulnerabiliBestoo

Page 27: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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PathMTUDiscovery•  DiscovertheMTUthatwillfit

–  SowecanavoidfragmentaBon–  Themethodinusetoday

•  Hosttestspathwithlargepacket–  Routersprovidefeedbackiftoolarge;theytellhostwhatsizewouldhavefit

Page 28: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

PathMTUDiscovery(2)

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Try1200 Try900

MTU=1200bytes MTU=900MTU=1400

Page 29: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

PathMTUDiscovery(3)

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Try1200 Try900

Test#2 Test#3Test#1

MTU=1200bytes MTU=900MTU=1400

Page 30: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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PathMTUDiscovery(4)•  Processmayseeminvolved

–  Butusuallyquicktofindrightsize

•  PathMTUdependsonthepathandsocanchangeoverBme–  Searchisongoing

•  ImplementedwithICMP(next)–  SetDF(Don’tFragment)bitinIPheadertogetfeedbackmessages

Page 31: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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Topic•  Whathappenswhensomethinggoeswrongduringforwarding?–  Needtobeabletofindtheproblem

Yikes!Whathappened?

XXXXXXX

Page 32: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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InternetControlMessageProtocol•  ICMPisacompanionprotocoltoIP

–  Theyareimplementedtogether–  SitsontopofIP(IPProtocol=1)

•  ProvideserrorreportandtesBng–  Errorisatrouterwhileforwarding–  AlsotesBngthathostscanuse

Page 33: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

ICMPErrors•  Whenrouterencountersanerrorwhileforwarding:

–  ItsendsanICMPerrorreportbacktotheIPsourceaddress–  ItdiscardstheproblemaBcpacket;hostneedstorecBfy

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Reportthentossit!Oh,nowIsee…XXXXXXX

ICMPreport

Page 34: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

ICMPMessageFormat•  EachICMPmessagehasaType,Code,andChecksum•  OXencarrythestartoftheoffendingpacketaspayload•  EachmessageiscarriedinanIPpacket

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Page 35: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

ICMPMessageFormat(2)•  EachICMPmessagehasaType,Code,andChecksum•  OXencarrythestartoftheoffendingpacketaspayload•  EachmessageiscarriedinanIPpacket

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Src=router,Dst=AProtocol=1 Type=X,Code=Y Src=A,Dst=B

XXXXXXXXXXXXXXX

PorBonofoffendingpacket,starBngwithitsIPheader

ICMPheaderIPheader ICMPdata

Page 36: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

ExampleICMPMessages

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Name Type / Code Usage Dest. Unreachable (Net or Host) 3 / 0 or 1 Lack of connectivity Dest. Unreachable (Fragment) 3 / 4 Path MTU Discovery Time Exceeded (Transit) 11 / 0 Traceroute Echo Request or Reply 8 or 0 / 0 Ping

TesBng,notaforwardingerror:HostsendsEchoRequest,anddesBnaBonrespondswithanEchoReply

Page 37: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

Traceroute•  IPheadercontainsTTL(Timetolive)field

–  Decrementedeveryrouterhop,withICMPerrorifithitszero–  Protectsagainstforwardingloops

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Page 38: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

Traceroute(2)•  TracerouterepurposesTTLandICMPfuncBonality

–  SendsprobepacketsincreasingTTLstarBngfrom1–  ICMPerrorsidenBfyroutersonthepath

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...LocalHost

RemoteHost1hop 2hops 3hops N-1hops Nhops

Page 39: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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Topic•  IPversion6,thefutureofIPv4thatisnow(sBll)beingdeployed

WhydoIwantIPv6again?

Page 40: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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•  AtleastabillionInternethostsandgrowing…

•  Andwe’reusing32-bitaddresses!

InternetGrowth

Page 41: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

TheEndofNewIPv4Addresses•  NowrunningonleXoverblocksheldbytheregionalregistries;muchBghterallocaBonpolicies

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IANA(AllIPs)

ARIN(US,Canada)

APNIC(AsiaPacific)

RIPE(Europe)LACNIC

(LaBnAmer.)AfriNIC(Africa)

ISPs

Companies

Exhaustedon2/11! Endoftheworld?12/21/12?

Exhaustedon4/11and9/12!

Page 42: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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IPVersion6totheRescue•  EffortstartedbytheIETFin1994

–  Muchlargeraddresses(128bits)–  Manysundryimprovements

•  BecameanIETFstandardin1998–  Nothingmuchhappenedforadecade–  Hamperedbydeploymentissues,andalackofadopBonincenBves

–  Bigpush~2011asexhausBonlooms

Page 43: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

IPv6Deployment

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Timeforgrowth!

Source:GoogleIPv6StaBsBcs,30/1/13

PercentageofusersaccessingGoogleviaIPv6

Page 44: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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IPv6•  Featureslargeaddresses

–  128bits,mostofheader

•  NewnotaBon–  8groupsof4hexdigits(16bits)–  Omitleadingzeros,groupsofzeros

Ex:2001:0db8:0000:0000:0000:ff00:0042:8329à

32bits

Page 45: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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IPv6(2)•  Lotsofother,smallerchanges

–  Streamlinedheaderprocessing–  Flowlabeltogroupofpackets–  Beserfitwith“advanced”features(mobility,mulBcasBng,security)

32bits

Page 46: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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IPv6TransiBon•  TheBigProblem:

–  HowtodeployIPv6?–  FundamentallyincompaBblewithIPv4

•  Dozensofapproachesproposed–  Dualstack(speakIPv4andIPv6)–  Translators(convertpackets)–  Tunnels(carryIPv6overIPv4)»

Page 47: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

Tunneling•  NaBveIPv6islandsconnectedviaIPv4

–  TunnelcarriesIPv6packetsacrossIPv4network

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Page 48: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

Tunneling(2)•  TunnelactsasasinglelinkacrossIPv4network

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User UserTunnel

Page 49: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

Tunneling(3)•  TunnelactsasasinglelinkacrossIPv4network

–  DifficultyistosetuptunnelendpointsandrouBng

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IPv6

Link

User User

IPv4Link

IPv6IPv6

Link

IPv6

LinkIPv4Link

IPv6 IPv6

Link

NaBveIPv4NaBveIPv6 NaBveIPv6

Tunnel

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Topic•  WhatisNAT(NetworkAddressTranslaBon)?Howdoesitwork?–  NATiswidelyusedattheedgesofthenetwork,e.g.,homes

I’maNATboxtoo!

Internet

Page 51: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

LayeringReview•  Rememberhowlayeringismeanttowork?

– “Routersdon’tlookbeyondtheIPheader.”Well…

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TCP

IP

802.11

App

IP

802.11

IPEthernet

TCP

IP

802.11

App

IP

802.11

IPEthernet

Router

Page 52: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

Middleboxes•  Sit“insidethenetwork”butperform“morethanIP”processingonpacketstoaddnewfuncBonality–  NATbox,Firewall/IntrusionDetecBonSystem

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TCP

IP

802.11

App

IP

802.11

IPEthernet

TCP

IP

802.11

App

IP

802.11

IPEthernet

Middlebox

App/TCP

Page 53: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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Middleboxes(2)•  Advantages

– ApossiblerapiddeploymentpathwhenthereisnootheropBon

–  Controlovermanyhosts(IT)

•  Disadvantages–  BreakinglayeringinterfereswithconnecBvity;strangesideeffects

–  Poorvantagepointformanytasks

Page 54: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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NAT(NetworkAddressTranslaBon)Box•  NATboxconnectsaninternalnetworktoanexternalnetwork– Manyinternalhostsareconnectedusingfewexternaladdresses

– Middleboxthat“translatesaddresses”

•  MoBvatedbyIPaddressscarcity–  Controversialatfirst,nowaccepted

Page 55: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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NAT(2)•  Commonscenario:

–  Homecomputersuse“private”IPaddresses–  NAT(inAP/firewall)connectshometoISP

usingasingleexternalIPaddress

ISP

Unmodifiedcomputersathome Lookslikeonecomputeroutside

NATbox

Page 56: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

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HowNATWorks•  Keepsaninternal/externaltable

–  TypicallyusesIPaddress+TCPport–  ThisisaddressandporttranslaBon

•  Needportstomakemapping1-1sincetherearefewerexternalIPs

Internal IP:port External IP : port 192.168.1.12 : 5523 44.25.80.3 : 1500 192.168.1.13 : 1234 44.25.80.3 : 1501 192.168.2.20 : 1234 44.25.80.3 : 1502

WhatISPthinksWhathostthinks

Page 57: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

HowNATWorks(2)•  InternalàExternal:

–  LookupandrewriteSourceIP/port

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Internal IP:port External IP : port 192.168.1.12 : 5523 44.25.80.3 : 1500

NATbox

ExternaldesBnaBonIP=X,port=Y

Internalsource

Src=Dst=

Src=Dst=

Page 58: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

HowNATWorks(3)•  ExternalàInternal

–  LookupandrewriteDesBnaBonIP/port

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Internal IP:port External IP : port 192.168.1.12 : 5523 44.25.80.3 : 1500

NATbox

Externalsource

IP=X,port=YInternal

desBnaBon

Src=Dst=

Src=Dst=

Page 59: Filling in the gaps we need to make for IP forwarding work ... · Layering Review • Remember how layering is meant to work? – “Routers don’t look beyond the IP header.”

HowNATWorks(4)•  NeedtoentertranslaBonsinthetableforittowork

–  CreateexternalnamewhenhostmakesaTCPconnecBon

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Internal IP:port External IP : port 192.168.1.12 : 5523

NATbox

ExternaldesBnaBonIP=X,port=Y

Internalsource

Src=Dst=

Src=Dst=

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NATDownsides•  ConnecBvityhasbeenbroken!

–  CanonlysendincomingpacketsaXeranoutgoingconnecBonissetup

–  Difficulttorunserversorpeer-to-peerapps(Skype)athome

•  Doesn’tworksowellwhentherearenoconnecBons(UDPapps)

•  BreaksappsthatunwiselyexposetheirIPaddresses(FTP)

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NATUpsides•  RelievesmuchIPaddresspressure

– ManyhomehostsbehindNATs•  Easytodeploy

–  Rapidly,andbyyoualone•  UsefulfuncBonality

–  Firewall,helpswithprivacy

•  Kinkswillgetworkedouteventually–  “NATTraversal”forincomingtraffic


Protocol Layering

Protocol Layering

Layering the cake

Layering the cake

3G Layering

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TCP/IP —— the Dominant Standards. TCP/IP Layering TCP and UDP are the two predominant transport layer protocols. Both use IP as the network layer.TCP.

TCP/IP —— the Dominant Standards. TCP/IP Layering TCP and UDP are the two predominant transport layer protocols. Both use IP as the network layer.TCP.

Patterns and layering

Patterns and layering

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ELEN602 Lecture 3 Review of last lecture –layering, IP architecture Data Transmission.

ELEN602 Lecture 3 Review of last lecture –layering, IP architecture Data Transmission.

Layering and Division - Wakefield FFA...Types of artifi cial layering that growers use include: • Simple layering. • Compound layering. • Air layering. • Mound layering. •

Layering and Division - Wakefield FFA...Types of artifi cial layering that growers use include: • Simple layering. • Compound layering. • Air layering. • Mound layering. •

1 Fall 2005 Internetworking: Concepts, Architecture and TCP/IP Layering Qutaibah Malluhi CSE Department Qatar University.

1 Fall 2005 Internetworking: Concepts, Architecture and TCP/IP Layering Qutaibah Malluhi CSE Department Qatar University.

layering demo

layering demo

Layering Masks

Layering Masks

Layering & Application Layer - TWikitwiki.di.uniroma1.it/pub/Reti_elab/AL/WebHome/Lezione_09_Ottobre... · " Reti sotto attacco: Sicurezza ... Internet protocol stack (TCP/IP) ! application:

Layering & Application Layer - TWikitwiki.di.uniroma1.it/pub/Reti_elab/AL/WebHome/Lezione_09_Ottobre... · " Reti sotto attacco: Sicurezza ... Internet protocol stack (TCP/IP) ! application:

Lecture 2: Layering & End-to-EndTelecollaboration TCP RSVP IP Ethernet ATM packet radio UDP SONET PPP air modem 100BT n Layering not strict • Can define new abstractions on any existing

Lecture 2: Layering & End-to-EndTelecollaboration TCP RSVP IP Ethernet ATM packet radio UDP SONET PPP air modem 100BT n Layering not strict • Can define new abstractions on any existing

PART X PROTOCOL LAYERING - Openloop Technologies · Internetworking With TCP/IP vol 1 -- Part 10 2 2005. ... Protocol Layering ... TCP/IP Layer 5: Application

PART X PROTOCOL LAYERING - Openloop Technologies · Internetworking With TCP/IP vol 1 -- Part 10 2 2005. ... Protocol Layering ... TCP/IP Layer 5: Application

OSI Layering

OSI Layering

Protocol Layering 97

Protocol Layering 97

Overview of Network Protocols, Services & Layering OSI Reference Model TCP/IP Architecture Error Detection and Correction.

Overview of Network Protocols, Services & Layering OSI Reference Model TCP/IP Architecture Error Detection and Correction.

Layering images

Layering images

Layering and physics

Layering and physics

Layering in Networked computing OSI Model TCP/IP Model Protocols at each layer.

Layering in Networked computing OSI Model TCP/IP Model Protocols at each layer.