How To Determine The How To Determine The Integrity of an Ethernet LineIntegrity of an Ethernet Line

Design Team 7Design Team 7

Mark JonesMark JonesSedat GurSedat Gur

Ahmed AlsinanAhmed AlsinanBrian SchulteBrian Schulte

Andy ChristophersonAndy Christopherson

IntroductionIntroduction

Ethernet History and StructureEthernet History and Structure Time Domain ReflectometryTime Domain Reflectometry Active Link Cable DiagnosticsActive Link Cable Diagnostics Digital Spectrum AnalysisDigital Spectrum Analysis Power-over-Ethernet DetectPower-over-Ethernet Detect Output DataOutput Data

History of EthernetHistory of Ethernet Computer based networking Computer based networking

technology for Local Area Networks technology for Local Area Networks (LANs)(LANs)

Developed by Xerox in Early 70’sDeveloped by Xerox in Early 70’s Used for approximately 85% of world’s LAN-Used for approximately 85% of world’s LAN-

connected PCs and workstationsconnected PCs and workstations Implemented with multiple types of cableImplemented with multiple types of cable

Coaxial Coaxial Twisted PairTwisted Pair Fiber OpticFiber Optic

Twisted Pair WiresTwisted Pair Wires Used in many Ethernet and Used in many Ethernet and

telephone systems telephone systems Receiver takes the difference Receiver takes the difference

between the wire pairbetween the wire pair Any interference in signal will be Any interference in signal will be

canceled outcanceled out AdvantagesAdvantages

Cables are thin, easy to run Cables are thin, easy to run throughout buildingthroughout building

FlexibleFlexible Cheap to manufactureCheap to manufacture

DisadvantagesDisadvantages Resistance to electromagnetic Resistance to electromagnetic

interference depends on pair interference depends on pair twisting scheme usedtwisting scheme used

Twisted Pair StandardsTwisted Pair Standards Category 3Category 3

Up to 10 MbpsUp to 10 Mbps Bandwidth up to 16 MHzBandwidth up to 16 MHz Popular in early 90’sPopular in early 90’s

Category 5Category 5 Used for mainly 100Mbps Used for mainly 100Mbps

networksnetworks Bandwidth up to 100MhzBandwidth up to 100Mhz

Category 5eCategory 5e Enhanced version of Category 5Enhanced version of Category 5 More rigorous standardsMore rigorous standards Recommended for most networksRecommended for most networks

Category 6Category 6 Bandwidth up to 250MHzBandwidth up to 250MHz Recommended for gigabit speedsRecommended for gigabit speeds

So what kind of errors are we So what kind of errors are we looking for?looking for?

Opens and ShortsOpens and Shorts Cable impedance mismatchCable impedance mismatch Bad connectorsBad connectors Terminations mismatchesTerminations mismatches Water damageWater damage Any other discontinuities Any other discontinuities

Also can find cable lengthAlso can find cable length

Time Domain ReflectometryTime Domain Reflectometry

Will diagnose opens, shorts, cable Will diagnose opens, shorts, cable impedance mismatch, bad connectors, impedance mismatch, bad connectors, termination mismatches, etc.termination mismatches, etc.

Uses reflections to find these errors and Uses reflections to find these errors and their locationstheir locations

Time Domain ReflectometryTime Domain Reflectometry

Pulse is transmitted of Pulse is transmitted of known amplitude known amplitude down twisted pairsdown twisted pairs

Reflects off Reflects off imperfections and imperfections and faultsfaults

Measure return time Measure return time and amplitude of and amplitude of reflectionsreflections

Time Domain ReflectometryTime Domain Reflectometry

With the gathered data we can findWith the gathered data we can find Distance and Magnitude (Impedance)Distance and Magnitude (Impedance) Non-terminated Cables (Opens and Shorts)Non-terminated Cables (Opens and Shorts) Discontinuities (Bad Connectors)Discontinuities (Bad Connectors) Improperly Terminated CablesImproperly Terminated Cables

Time Domain ReflectometryTime Domain Reflectometry

Active Link Cable DiagnosticsActive Link Cable Diagnostics

Use of passive digital signal processingUse of passive digital signal processing Will find cable length with active cableWill find cable length with active cable

Uses predefined parameters based on the Uses predefined parameters based on the cable propertiescable properties High accuracy cable lengthHigh accuracy cable length

Spectrum AnalysisSpectrum Analysis

Analog Spectrum AnalysisAnalog Spectrum Analysis Uses a variable band-pass filterUses a variable band-pass filter

Digital Spectrum AnalysisDigital Spectrum Analysis Uses Discrete Fourier TransformUses Discrete Fourier Transform

Results in frequency spectrum of our signalResults in frequency spectrum of our signal

Digital Spectrum AnalysisDigital Spectrum Analysis

Gives magnitude of Gives magnitude of the frequency the frequency responseresponse This will show us how This will show us how

the signal is spread the signal is spread out along the out along the frequency spectrumfrequency spectrum

Allow us to see noise Allow us to see noise along the linealong the line Especially how it Especially how it

relates to the length of relates to the length of the cablethe cable

Power-over-Ethernet DetectPower-over-Ethernet Detect

Power can run over 2 pairs of wires while data is Power can run over 2 pairs of wires while data is on the remaining 2 pairson the remaining 2 pairs

Power is supplied by a PSE and received by the Power is supplied by a PSE and received by the PD. PD. 42~57 Volts 42~57 Volts

Power-over-Ethernet DetectPower-over-Ethernet Detect

Detection Level can be varied as well as Detection Level can be varied as well as Turn-on and Turn-off voltagesTurn-on and Turn-off voltages

PHY to MAC CommunicationPHY to MAC Communication

PHY LayerPHY Layer Transmission of raw Transmission of raw

bits, not logical databits, not logical data

MAC LayerMAC Layer Logical communicationLogical communication

PHY to MAC CommunicationPHY to MAC Communication

Microcontroller (MCU) Microcontroller (MCU) Able to communicate with PHY layerAble to communicate with PHY layer

Uses Media Independent Interface (MII)Uses Media Independent Interface (MII)

Readable InterfaceReadable Interface

Microcontroller can be programmed to Microcontroller can be programmed to send data tosend data to LCD DisplayLCD Display ComputerComputer LEDsLEDs

PHY to YOUPHY to YOU

ConclusionConclusion

Ethernet History and StructureEthernet History and Structure Time Domain ReflectometryTime Domain Reflectometry Active Link Cable DiagnosticsActive Link Cable Diagnostics Digital Spectrum AnalysisDigital Spectrum Analysis Power-over-Ethernet DetectPower-over-Ethernet Detect Output DataOutput Data

QUESTIONS?QUESTIONS?