Cisco Presentation Guide

EthernetEthernet

PetrPetr GrygGrygáárekrek

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 1 EthernetEthernet HistorHistoryy •ResearchResearch background:background: AlohaNetAlohaNet •UniversityUniversity ofof Hawai,Hawai, 19701970:: commoncommon (radio)(radio) channelchannel sharingsharing methodsmethods –– basisbasis forfor CSMA/CDCSMA/CD •1980:1980: DIXDIX publishedpublished EthernetEthernet standardstandard (Metcalfe)(Metcalfe) •1985:1985: IEEEIEEE 802802.3.3 (MAC(MAC andand LLCLLC layers)layers) •10Base5,10Base5, 10Base2,10Base2, 10BaseT10BaseT •19951995 IEEEIEEE 802.3u802.3u (Fast(Fast Ethernet)Ethernet) •19981998 IEEEIEEE 802.3z802.3z (Gigabit(Gigabit Ethernet)Ethernet) •20022002 IEEEIEEE 802.3ae802.3ae (10Gb(10Gb Ethernet)Ethernet) •......

MbpsMbps [Base|Broad][Base|Broad] [segment[segment_length_length_m_m || -medium-medium]]

--TT -- TwistedTwisted Pair,Pair, --FF -- FiberFiber optic,optic, ...... e.g.e.g. 10Base5,10Base5, 10BaseT,10BaseT, 100BaseF100BaseF

NameName ofof eacheach particularparticular EthernetEthernet technologytechnology defineddefined inin individualindividual supplementsupplementss ofof 802.3802.3 standardstandard •e.ge.g 802.3u,802.3u, 802.3ab,802.3ab, 802.3z802.3z

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 3 Half-duplexHalf-duplex andand Full-duplexFull-duplex EthernetEthernet •HalfHalf duplexduplex –– colissioncolission envirnmentenvirnment (CSMA/CD)(CSMA/CD) •FullFull duplexduplex -- colission-freecolission-free (switched)(switched) environmentenvironment

InIn half-duplexhalf-duplex modemode wewe havehave toto adhereadhere CSMA/CSMA/ CDCD timingtiming thatthat impliesimplies thethe maximummaximum cablecable lengthslengths ForFor compatibilitycompatibility withwith half-duplexhalf-duplex NICs,NICs, P2PP2P linkslinks maymay alsoalso operateoperate inin half-duplexhalf-duplex modemode © 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 4 HistoricalHistorical EthernetEthernet ImplementationsImplementations

== ThickThick EthernetEthernet == DIXDIX EthernetEthernet == ETHERNETETHERNET IIII

•BusBus (coax)(coax) „Yellow„Yellow Cable“Cable“ •50ohm,50ohm, diameterdiameter ofof 1010 mmmm •MaxMax segmentsegment lengthlength 500m,500m, terminatedterminated •MaxMax 55 segmentssegments interconnectedinterconnected byby 44 repeaters,repeaters, stationsstations maymay bebe placedplaced onlyonly onon 33 segmentssegments (5-4-3(5-4-3 rule)rule) •MaxMax 100100 stationsstations perper segment,segment, minimumminimum distancedistance ofof 2.52.5 mm •ManchesterManchester encodingencoding •UtilizesUtilizes externalexternal transceiverstransceivers (AUI(AUI interface)interface) •AttachedAttached toto busbus byby T-connectorT-connector oror wampirewampire taptap © 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 7 10Base210Base2 == ThinThin EthernetEthernet == CheaperNetCheaperNet

•bus,bus, coaxcoax RG58RG58 •50ohm,50ohm, diameterdiameter ofof 55 mm)mm) •MaxMax segmentsegment lengthlength 185m,185m, terminatedterminated •5-4-35-4-3 rulerule •MaxMax 3030 stationsstations perper segment,segment, minimumminimum distancedistance 0.5m0.5m •Interconnection:Interconnection: BNCBNC andand TT connectorsconnectors •TransceiverTransceiver isis integratedintegrated onon thethe NICNIC © 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 8 10BaseT10BaseT •StarStar (tree)(tree) topologytopology •22 twistedtwisted pairspairs (UTP3)(UTP3) ++ RJ-45RJ-45 connectorsconnectors •MayMay operateoperate inin full-duplexfull-duplex modemode whenwhen switchesswitches areare appliedapplied •StationsStations interconnectedinterconnected withwith hubshubs •5-4-(3)5-4-(3) rulerule •mmax.ax. 512512 stationsstations inin thethe wholewhole treetree •MaxMax 100m100m betweenbetween hubhub andand NICNIC •minmin 0.6m0.6m •CrossingCrossing ofof transmittertransmitter andand receiverreceiver cable pairs cable© 2009 Petr Grygárek,pairs FEI VŠB-TU Ostrava, Computer Networks (Bc.) 9 FastFast EthernetEthernet (100Mbps)(100Mbps)

•IEEEIEEE 802.3u802.3u •BasedBased onon 10BaseT10BaseT •thethe samesame MACMAC addressaddress protocolprotocol andand frameframe formatformat •NICsNICs areare obviouslyobviously backwardbackward compatiblecompatible withwith 10BaseT10BaseT •SpeedSpeed autonegotiationautonegotiation capabilitycapability •differentdifferent lineline encodingencoding •UsesUses UTP5,UTP5, 100m100m betweenbetween networknetwork devicesdevices

© 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 10 PhysicalPhysical LayerLayer ofof FastFast EthernetEthernet •100BaseTX:100BaseTX: UTP5,UTP5, STPSTP –– UTP5,UTP5, maxmax 100m,100m, 4B5B4B5B ++ MLT3,MLT3, 125125 MHzMHz •100BaseFX:100BaseFX: FO,FO, max.max. distancedistance NIC-NIC- hubhub isis 200m200m (because(because ofof CSMA/CD)CSMA/CD) •OtherOther sparselysparsely usedused optionsoptions •DevelopedDeveloped forfor compatibilitycompatibility withwith olderolder cablingscablings -- 100BaseT2,100BaseT2, 100BaseT4100BaseT4

© 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 11 FastFast EthernetEthernet TopologiesTopologies (half-duplex)(half-duplex) •22 directlydirectly connectedconnected NICsNICs •StarStar withwith ClassClass II hubhub •TwoTwo ClassClass IIII hubshubs interconnectedinterconnected byby lineline ofof maximummaximum 1010 mm inin lengthlength

HubHub classclass II andand IIII differdiffer inin •MaximumMaximum allowedallowed signalsignal delaydelay •CapabilityCapability ofof encodingencoding transformation,transformation, i.e.i.e. thethe abilityability ofof usingusing differentdifferent mediamedia inin aa singlesingle collisioncollision domaindomain •e.g. transformaiton of 100BaseTX to 100BaseT4

•EthernetEthernet todaytoday isis aa wholewhole familyfamily ofof networkingnetworking technologiestechnologies (100Mbps+)(100Mbps+) •LAN,LAN, MAN,MAN, WANWAN •CompatibilityCompatibility stillstill maintainedmaintained

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 13 GigabitGigabit EthernetEthernet (802.3z)(802.3z) •DevelopedDeveloped sincesince 1995,1995, originallyoriginally supposedsupposed toto requirerequire fiberfiber opticoptic oror coaxcoax cable,cable, standardstandard laterlater extendedextended forfor twistedtwisted pairpair •802.3ab802.3ab –– compatiblecompatible withwith existingexisting wiringswirings (Cat5e)(Cat5e) •MakesMakes thethe standardstandard EthernetEthernet fasterfaster againagain • CSMACSMA oror switching,switching, IEEEIEEE 802.3802.3 frame,frame, simplesimple starstar topologytopology •ProblemsProblems withwith minimumminimum frameframe lengthlength inin collision-modecollision-mode whenwhen tryingtrying toto keepkeep thethe samesame maximummaximum cablecable lengthslengths asas withwith 10BaseT10BaseT •AppendsAppends aa paddingpadding toto 512B512B intointo aa frameframe ifif necessarynecessary oror appliesapplies packetpacket bursting.bursting. • MostMost commonlycommonly usedused forfor backbonebackbone linkslinks © 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 14 PhysicalPhysical LayerLayer ofof thethe GigabitGigabit EthernetEthernet • 1000Base-T:1000Base-T: UTP5eUTP5e • All 4 pairs used simultaneously in both directions (PAM5, echo cancellation), max. 100m • Problems with reflections connectors (the cabling system may start to resonate) • 1000Base-SX1000Base-SX (short(short wavelength-850wavelength-850 nm)nm) –– usedused moremore oftenoften • 8B10B encoding • 62.5 um MMF 440m, 50 um MMF 550m • 1000Base-LX1000Base-LX (long(long wavelength-1300wavelength-1300 nm)nm) • 8B10B encoding • SMF 3 km, 62.5 um MMF 440m, 50 um MMF 550m. • Usage of „offsets“ to limit transversal modes on MMF (decreases dispersion) • ANSIANSI FibreFibre ChannelChannel • Supports bandwidths of 133Mpbs to 1Gbps on various cable types (MMF, STP, coax) © 2009 Petr Grygárek, FEI VŠB-TU Ostrava, Computer Networks (Bc.) 15 1000BaseX1000BaseX ((802.3z802.3z)):: FiberFiber OpticsOptics •extendsextends thethe originaloriginal LANLAN technologytechnology toto distancesdistances thatthat makemake EthernetEthernet aa WAN/MANWAN/MAN standardstandard •1000BASE-1000BASE-SXSX •850nm850nm laser/LEDlaser/LED,, MMMM fiber,fiber, SCSC –– lowlow costcost •distancesdistances 220-550m220-550m ((betterbetter forfor 50/12550/125 thanthan 62.5/5062.5/50 fiberfiber)) •1000BASE-1000BASE- LXLX •1310nm1310nm laserlaser SMSM fiberfiber (5km)(5km) oror MMMM fiberfiber (500m)(500m),, SCSC •8B10B+NRZ8B10B+NRZ ("level-driven")("level-driven") encodingencoding •SomeSome bitbit combinationcombination havehave alternativealternative 8B10B8B10B codewordscodewords •chosen dynamically to reach balanced bit pattern •BecauseBecause ofof highhigh rate,rate,11ss andand 00ss encodedencoded withwith lowlow andand highhigh powerpower insteadinstead ofof presence/absencepresence/absence ofof lightlight © 2005 Petr Grygarek, Advanced Computer Networks Technologies 16 1000BaseT1000BaseT (802.3ab)(802.3ab) • usesuses TPTP CategoryCategory 5e5e oror higherhigher • cat5e allows 125Mbps • allall fourfour pairs,pairs, 125125 MbdMbd eacheach • 4D-PAM54D-PAM5 lineline encodingencoding • pulse amplitude modulation, 5 states •2bits/symbol + Forward Error Correction (8-state Trellis code) • control and data symbols •250 Mbps/pair if 125 Mbd used • 4x in parallel (for each pair) • See http://www.reed- electronics.com/tmworld/article/CA287078.html • FFullull duplexduplex:: echoecho ccancellation,ancellation, onon allall pairspairs • 9 voltage levels in idle periods, 17 during data transmission • need to synchronize clocks (clock master elected) • problems with reflections (danger of resonance) © 2005 Petr Grygarek, Advanced Computer Networks Technologies 17 EthernetEthernet inin DepthDepth

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 18 EthernetEthernet AdvantagesAdvantages •SimplicitySimplicity •lowerlower learninglearning andand implementationimplementation costcost •preferredpreferred overover (more(more sophisticated)sophisticated) FDDI,FDDI, ATMATM etc.etc. •ScalabilityScalability •maintainsmaintains thethe samesame frameframe formatformat atat allall transfertransfer ratesrates •CompatibilityCompatibility •frameframe formatformat (including(including MACMAC addressaddress format)format) •CSMA/CDCSMA/CD ((untiluntil 1000Base1000Base--T)T) •ModularityModularity •OnlyOnly physicalphysical layerslayers differsdiffers © 2005 Petr Grygarek, Advanced Computer Networks Technologies 19 LegacyLegacy Ethernet:Ethernet: CommonCommon CharacteristicsCharacteristics •10Base5-1980,10Base5-1980, 10Base2-1985,10Base2-1985, 10BaseT-199010BaseT-1990 •TimingTiming parametersparameters (100ns(100ns bitbit timeslot,timeslot, 51.2us51.2us slotslot time)time) •FrameFrame formatformat •TransmissionTransmission processesprocesses •ManchesterManchester encodingencoding •CSMA/CDCSMA/CD (half(half duplex)duplex) •full duplex defined later for 10BaseT (1997) •BasicBasic designdesign rulerule (5-4-3)(5-4-3) •NoNo moremore thanthan fourfour repeatersrepeaters cancan bebe usedused inin seriesseries betweenbetween anyany twotwo stations.stations. ThereThere cancan alsoalso bebe nono moremore thanthan threethree populatedpopulated segmentssegments betweenbetween anyany twotwo stations.stations. © 2005 Petr Grygarek, Advanced Computer Networks Technologies 20 EthernetEthernet FrameFrame

•Preamble:Preamble: 7x7x 10101010,10101010, 1x1x 1010101110101011 (SFD)(SFD) •necessarynecessary onlyonly forfor (asynchronous)(asynchronous) 10Mbps10Mbps EthernetEthernet •TypeType<0x600<0x600 (1536):(1536): interpretedinterpreted asas lengthlength (IEEE),(IEEE), protocolprotocol typetype otherwiseotherwise (DIX)(DIX) •DataData 46-1500B46-1500B •CRCCRC 4B4B

•extraextra 2+22+2 bytesbytes (priority,(priority, VLANVLAN ID)ID) •InsertedInserted behindbehind TYPETYPE fieldfield •IndicatedIndicated byby TYPE=8100hTYPE=8100h •OriginalOriginal TYPETYPE repeatedrepeated justjust behindbehind 802.1q802.1q headerheader

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 22 TimingTiming •PropagationPropagation delaydelay (UTP)(UTP):: 20.320.3 cm/ns,cm/ns, •100m100m UTPUTP == 55 bitbit timestimes (10Mbps)(10Mbps) •SlotSlot timetime == miminniimmumum frameframe durationduration •512bit512bit timestimes ((64B64B)) forfor 1010 andand 100100 MMbpsbps EthernetEthernet •40964096 bitbit timtimee slotsslots (512(512 B)B) forfor 10001000 MMbpsbps •calculacalculatteded assumingassuming maximumaximumm cablecable lengthslengths (and(and repeaterrepeater delay)delay) •maxmax delaydelay defineddefined asas 51,251,2 mimiccrorosecondsseconds •32bit32bit ““jamjam”” signalsignal •InterframeInterframe spacingspacing 9696 bitbit timetimeslotsslots •timetime thatthat allowsallows receiver(s)receiver(s) toto processprocess frameframe andand prepareprepare forfor anotheranother frameframe receptionreception

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 23 TimingTiming ConsiderationsConsiderations forfor Mixed-mediaMixed-media NetworkNetwork DesignDesign •CableCable lengthlength •VelocityVelocity ofof signalsignal propagationpropagation •TransceiverTransceiver delaydelay •RepeaterRepeater delaydelay •InterframeInterframe gapgap shrinkageshrinkage duedue toto repeatersrepeaters •repeaterrepeater isis expectedexpected toto regenerateregenerate allall 6464 bitsbits ofof preamble,preamble, despitedespite thethe potentialpotential lossloss ofof somesome ofof thethe strartingstrarting preamblepreamble bitsbits becausebecause ofof slowslow synchronizationsynchronization •tthishis forcedforced reintroductionreintroduction ofof timingtiming bitsbits reducesreduces originaloriginal interframeinterframe gapgap •ProcessingProcessing delaydelay inin stationstation NIC’sNIC’s CPUCPU © 2005 Petr Grygarek, Advanced Computer Networks Technologies 24 CollisionsCollisions •WWhenhen aa transmittingtransmitting stationstation detectsdetects aa collision,collision, itit stopsstops sendingsending it'sit's frameframe andand sendssends 32bit32bit JamJam sequencesequence toto announceannounce collisioncollision toto otherother stationsstations •jamjam signalsignal maymay bebe composedcomposed ofof anyany binarybinary datadata thatthat dodo notnot formform thethe properproper checksumchecksum forfor thethe portionportion ofof thethe frameframe alreadyalready transmittedtransmitted •mostmost commonlycommonly 101010…101010… •TheThe majoritymajority ofof collisionscollisions occuroccurss veryvery earlyearly inin thethe frame,frame, oftenoften beforebefore thethe SFDSFD •CollisionCollision fragmentsfragments == framesframes <<64B64B withwith wrongwrong CRCCRC © 2005 Petr Grygarek, Advanced Computer Networks Technologies 25 CollisionCollision DetectionDetection •Coax:Coax: amplitudeamplitude ofof thethe signalsignal onon thethe networknetwork mediamedia increasesincreases •ManchesterManchester characteristics:characteristics: numbernumber ofof HighHigh levellevel intervalsintervals =number=number ofof LowLow levellevel intervals,intervals, averageaverage shouldshould bebe 00 •IfIf twotwo ManchesterManchester waveformwaveform mix,mix, averageaverage levellevel movesmoves •waveformwaveform cancan bebe smoothedsmoothed andand levellevel measuredmeasured onon capacitorcapacitor •UTP:UTP: signalsignal onon RXRX pairpair whilewhile transmittingtransmitting onon TXTX pairpair © 2005 Petr Grygarek, Advanced Computer Networks Technologies 26 CollisionCollision TypesTypes

•LocalLocal collisioncollision •simultaneoussimultaneous transmissiontransmission ofof multiplemultiple stationsstations onon thethe samesame coaxialcoaxial segment,segment, detecteddetected asas amplitudeamplitude increaseincrease (signal(signal “sums“sums up”up” onon terminators)terminators) •RemoteRemote collisioncollision •collisioncollision behindbehind repeaterrepeater •cannotcannot bebe detecteddetected byby amplitudeamplitude increaseincrease (repeater(repeater willwill notnot passpass it)it) oror byby simultaneoussimultaneous signalsignal onon RXRX andand TXTX pairpair •identifiedidentified byby presencepresence ofof collisioncollision fragmentfragment (short(short frameframe withwith wrongwrong CRC)CRC)

•CollisionCollision outout ofof thethe timeslottimeslot (after(after firstfirst 64B64B)) •NICNIC willwill notnot repeatrepeat thethe transmittedtransmitted frameframe

•10Mbps:10Mbps: synchronizessynchronizes beforebefore everyevery frameframe independentlyindependently usingusing preamblepreamble (“asynchronous(“asynchronous Ethernet”)Ethernet”) •fasterfaster versions:versions: synchronizationsynchronization alwaysalways maintainedmaintained •usingusing reservedreserved “idle”“idle” symbolssymbols

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 29 100BaseTX,100BaseTX, 100BaseFX100BaseFX (1995)(1995) •100BaseTX100BaseTX ((UTP5UTP5)) •4B5B4B5B •reserved symbols for frame delimitation and idle link indication •125 Mbaud •ScramblScramblinging •MLT3MLT3 -- MuLTilevelMuLTilevel encodingencoding •3-level code, cycles in sine-like style, change represents 1, same level represents 0 •100BaseFX100BaseFX (FO)(FO) •4B5B4B5B •NRZINRZI •change in the middle of bit time represents 1, change absence represents 0

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 30 100BaseT2,100BaseT2, 100BaseT4100BaseT4 (1)(1) •ProposedProposed technologiestechnologies forfor UTP3UTP3 •DidDid notnot reachedreached aa widespreadwidespread usageusage •USUS UTPUTP CatCat 33 installationsinstallations onlyonly •HelpedHelped toto developdevelop technologiestechnologies applicableapplicable inin GigabitGigabit EthernetEthernet •multilevelmultilevel encoding,encoding, echoecho cancellationcancellation

•100Base-T4100Base-T4 •11 pairpair ->-> 11 pairpair <-,<-, 22 pairspairs switchswitch directionsdirections •8B6T8B6T encodingencoding •22 ofof thethe resultingresulting 3-state3-state symbolssymbols areare sentsent overover eacheach ofof 33 pairspairs •100100 Base-T4Base-T4 •22 pairspairs • 44 bitsbits transformedtransformed toto 22 3-bit3-bit symbolssymbols (complex(complex scrambling),scrambling), followedfollowed byby PAM5PAM5

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 33 AutonegotiationAutonegotiation ofof CapabilitiesCapabilities •10BaseT:10BaseT: NormalNormal LinkLink PulsePulse (NLP)(NLP) everyevery 16.816.8 msms–– usedused forfor linklink integrityintegrity testtest onlyonly •pulsespulses presentpresent whenwhen aa stationstation hashas nothingnothing toto sendsend •FastFast EthernetEthernet && later:later: FastFast LinkLink PulsesPulses (FLP)(FLP) •FLPFLP burstburst -- sentsent inin NLPNLP intervalsintervals forfor compatibilitycompatibility reasonsreasons

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 34 FLPFLP BurstsBursts •datadata pulsespulses interleavedinterleaved withwith clockclock pulsespulses andand carrycarry 1616 bitbit LinkLink CodeCode WordWord (LCW)(LCW) •LCWLCW consistsconsists ofof 1717 toto 3333 NLPsNLPs andand takestakes 2ms2ms inin totaltotal •LCWLCW announcesannounces device’sdevice’s capabilitiescapabilities toto it’sit’s linklink partnerpartner

SelectorSelector impliesimplies howhow toto interpretinterpret TechnologyTechnology AbilityAbility FieldField • selectorselector valuevalue 0000100001 assignedassigned toto IEEEIEEE 802.3802.3 • ForFor details,details, seesee http://www.http://www.scyldscyld..comcom// NWayNWay..htmlhtml

•speedspeed (+modulation/pair(+modulation/pair usage)usage) •duplexduplex •clockclock mastermaster (Gigabit(Gigabit Ethernet)Ethernet) •……

• AfterAfter bothboth linklink partnerspartners havehave interpretedinterpreted otherother side’sside’s LCWs,LCWs, theythey startstart toto useuse “highest”“highest” capabilitiescapabilities supportedsupported byby bothboth ofof themthem • CapabilityCapability priorities:priorities: • 1000Base-T FD • 1000Base-T HD • 100Base-TX FD • 100BASE-T4 • 100BASE-TX HD • 10BASE-T FD • 10BASE-T HD

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 38 CapabilityCapability negotiationnegotiation processprocess (2)(2) •StationStation aattemptttemptss toto detectdetect andand useuse 100BaseTX100BaseTX signallingsignalling beforebefore autonegotiationautonegotiation •IIff linklink partnerpartner doesdoes’’nn offeroffer FLPFLPss butbut offersoffers NLPNLPss,, 10BaseT10BaseT isis assumedassumed •IfIf thethe linklink isis lost,lost, linklink partnerspartners firstfirst attemptattempt toto connectconnect atat thethe lastlast negotiatednegotiated speed.speed. IfIf thatthat fails,fails, oror linklink waswas downdown forfor longlong,, autoneautonegotiationgotiation startsstarts again.again.

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 39 802.3x802.3x FlowFlow ControlControl (full(full duplex)duplex) •LinkLink layerlayer •PAUSEPAUSE frameframe •EtherTypeEtherType 8808h8808h •ReservedReserved destinationdestination MACMAC addressaddress •notnot forwardedforwarded byby switchswitch •SimilarSimilar toto Xon/Xoff,Xon/Xoff, butbut withwith timeouttimeout forfor XoffXoff •ParameterParameter specifiesspecifies numbernumber ofof unitsunits toto waitwait •00 cancelscancels PAUSEPAUSE requestrequest

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 41 10Gbps10Gbps EthernetEthernet •BitBit timetime 0.10.1 nsns (=100ps(=100ps (!)),(!)), IFGIFG 9696 bitsbits •FullFull duplexduplex onlyonly •nono moremore collisioncollision timingtiming calculationcalculation •MuchMuch moremore WANWAN//MANMAN oror datadata centercenter technologytechnology •butbut stillstill interoparableinteroparable withwith EthernetEthernet LAN‘sLAN‘s frameframe formatformat (!)(!) •PhysicalPhysical layer:layer: • Fiber • Copper (Cat6a) • Twinax (similar to 2x coax) • WAN PHY

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 42 10GE10GE onon FiberFiber (10GBase-R)(10GBase-R) 802.3ae802.3ae • 10GBASE-SR10GBASE-SR (short(short reach)reach) •MMF,MMF, 850nm850nm laser,laser, 64B/66B64B/66B •2626-82m-82m • 10GBASE-LR10GBASE-LR (long(long reach)reach) •SMF,SMF, 1310nm1310nm laser,laser, 64B/66B64B/66B •1010 kmkm andand 4040 kmkm overover SMFSMF • 10GBASE-ER10GBASE-ER (extended(extended reach)reach) •SMF,SMF, 1550nm1550nm laser,laser, 64B/66B64B/66B •4040 kmkm overover SMFSMF • 10GBASE-LX410GBASE-LX4 •coarsecoarse WDMWDM (4x(4x 1300nm1300nm laser)laser) •MMF,MMF, 240-300m240-300m © 2005 Petr Grygarek, Advanced Computer Networks Technologies 43 10GE10GE onon CopperCopper (10GBase-T)(10GBase-T) 802.3ab802.3ab •10GBASE-CX410GBASE-CX4 –– specialspecial cablecable •10GBASE-T10GBASE-T –– STP/UTPSTP/UTP •45m45m onon Cat5e,Cat5e, 55m55m onon Cat6Cat6 •100m100m onon Cat6aCat6a (partitioned)(partitioned) •PAM16+complicatedPAM16+complicated encodingencoding

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 44 EthernetEthernet WANWAN PHYsPHYs ((10GBASE-W)10GBASE-W) • 10GBASE-SW,10GBASE-SW, 10GBASE-LW,10GBASE-LW, 10GBASE-EW,10GBASE-EW, andand 10GBASE-Z10GBASE-Z •CorrespondCorrespond toto 10GBASE-SR,10GBASE-SR, 10GBASE-LR,10GBASE-LR, 10GBASE-ER10GBASE-ER andand 10GBASE-ZR10GBASE-ZR • UseUse OC-192/STM-64OC-192/STM-64 SDH/SONETSDH/SONET (9.953(9.953 Gbit/s)Gbit/s)

• 4040 GBGB usingusing DWDMDWDM •4x4x 10Gbps10Gbps carrierscarriers • UpcomingUpcoming standards:standards: •40/10040/100 GbEGbE -- IEEEIEEE P802.3baP802.3ba •underunder developmentdevelopment •singlesingle lightlight sourcesource •variousvarious PHYPHY typestypes •maximummaximum compatibilitycompatibility withwith 803.3803.3 framingframing

• CollisionCollision -- ssimultaneousimultaneous transmissiontransmission occurringoccurring beforebefore slotslot timetime (64/512B)(64/512B) hashas elapsedelapsed • LateLate collisioncollision -- ssimultaneousimultaneous transmissiontransmission occurringoccurring afterafter slotslot timetime hashas elapsedelapsed • NIC does not retransmit the frame (!) • JJabber,abber, longlong frameframe,, rangerange errorserrors -- eexcessivelyxcessively oror illegallyillegally longlong transmissiontransmission • SShorthort frame,frame, collisioncollision fragmentfragment,, runtrunt -- iillegallyllegally shortshort transmissiontransmission • collision fragment - partial frames < 64B with invalid CRC •typically result of remote collision • if signal it does not exhibit the local collision symptoms • runt = <64B, correct FCS • FCSFCS errorerror -- CorruptedCorrupted transmissiontransmission © 2005 Petr Grygarek, Advanced Computer Networks Technologies 48 EthernetEthernet statisticsstatistics terminologyterminology (2)(2) •AlignmentAlignment errorerror -- InsufficientInsufficient oror excessiveexcessive numbernumber ofof bitsbits transmittedtransmitted •OutOut ofof rangerange errorerror -- illegalillegal LengthLength valuevalue (too(too large)large) •RangeRange errorerror -- aactualctual andand reportedreported (Length(Length field)field) numbernumber ofof octetsoctets inin frameframe dodo notnot matchmatch •tootoo smallsmall LengthLength valuevalue oror LengthLength doesdoes notnot matchmatch thethe actualactual numbernumber ofof octetsoctets receivedreceived •GhostGhost oror jabberjabber -- UnusuallyUnusually longlong PreamblePreamble oror JamJam signalsignal •Ghost:Ghost: noisenoise >72B,>72B, withoutwithout validvalid SFDSFD •Jabber:Jabber: >20000>20000 bitbit timestimes

© 2005 Petr Grygarek, Advanced Computer Networks Technologies 49 SignalSignal QualityQuality ErrorError (SQE)(SQE) signalsignal ofof AUIAUI transceiverstransceivers • sentsent byby aa transceivertransceiver backback toto thethe controllercontroller toto letlet thethe controllercontroller knowknow whetherwhether thethe collisioncollision circuitrycircuitry isis functional.functional. • designeddesigned toto fixfix thethe problemproblem inin earlierearlier versionsversions ofof EthernetEthernet wherewhere aa hosthost doesdoes notnot knowknow ifif aa transceivertransceiver isis connected.connected. • SQESQE isis active:active: • Within 4 to 8 microseconds after a normal transmission to indicate that the outbound frame was successfully transmitted • Whenever there is a collision on the medium • Whenever there is an improper signal on the medium (jabber, cable short) • Whenever a transmission has been interrupted © 2005 Petr Grygarek, Advanced Computer Networks Technologies 50 UsefulUseful EthernetEthernet informationinformation •http://www.ieee.orghttp://www.ieee.org •http://www.http://www.ethermanageethermanage..comcom// ethernetethernet