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    Ethernet

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    The term Ethernetrefers to the family of local-area.

    standard. Three data rates are currently defined foro eration over o tical fiber and twisted- air cables:

    10 Mbps10Base-T Ethernet

    100 MbpsFast Ethernet 1000 MbpsGigabit Ethernet

    10-Gigabit Ethernet is under development and will

    e y e pu s e as t e . ae supp ement tothe IEEE 802.3 base standard in late 2001 or early

    .

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    There are LOTS of LAN protocols

    r ce

    Performance

    Availability

    Ease of use Scalability

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    Ethernets peak utilization is pretty low (like Aloha)

    More hosts

    Smaller packet sizes

    More frequent arbitration

    Longer links

    Collisions take longer to observe, more wasted

    an w t Efficiency is improved by avoiding these conditions

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    Found by Xerox Palo Alto Research Center (PARC) in 1975

    Original designed as a 2.94 Mbps system to connect 100computers on a 1 km cable

    Later, Xerox, Intel and DEC drew up a standard support 10Mbps

    Basis for the IEEEs 802.3 specification

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    Ethernet defined as IEEE 802.3.

    The IEEE 802.* set of standards defines a common framing anda ress ng ormat or protoco s. Simplifies interoperability Addresses are 48 bit strings, with no structure

    .

    802.4 (Token bus)

    802.5 (Token ring) 802.6 (Distributed queue dual bus) 802.11 (Wireless LAN) 802.14 Cable Modem

    802.15 (Wireless Personal Area networks - based onbluetooth)

    - .

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    10Base5 10BaseT 10baseFL 100BaseTX 100BaseFXMedia Thick coax

    RG-8,

    TIA/EIA

    UTP Cat

    3,4,5,5e,6

    62.2/125

    Multi-

    TIA/EIA

    UTP Cat 5

    and u 2

    62.2/125

    Multi-mode

    -

    (2 pair) Fiberpair)

    Or Singlemode fiber

    Speed 10 Mbps 10 Mbps 10 Mbps 100 Mbps 100 Mbps

    Max

    Seg.

    500 Meters 100

    Meters

    2000

    Meters

    100 Meters 400/2000

    Meters

    Length (full/half duplex), 10

    Km

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    Copper technology

    Category 5 cable (UTP/Shielded TP)

    Cate or 6a cable

    Coaxial cable

    O tical technolo Multimode 63,5/125 m

    Multimode 50/125 m

    Singlemode 125 m

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    Copper technology typically uses RJ45 plugs/jacks for TP

    BNC for coaxial 50 Ohm cable

    F-Type connector for coaxial 75 Ohm cable

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    568-a 568-b

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    Pinout 10/100 Ethernet Twisted Pair

    Use of more airs for hi her transmission rates

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    Block Line

    ase anc es er

    10BaseF N/A NRZI

    ase anc ester

    100BaseT4 8B6T N/A100BaseF 4B/5B NRZI

    1000BaseT 4D-PAM5 N/A

    1000BaseF 8B/10B NRZI

    10gae 8B/10B or NRZI

    64B/66B

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    - changes level for a 1 bit

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    The workmark comes from telegraphy and means 1.

    AMI means alternate 1 inversion

    The neutral zero voltage represents binary 0. Binary 1s are represented by alternating positive and negative

    .

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    - changes level for a 0 bit

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    A binary 1 is encoded as an NRZ pulse with alternate

    +

    A binary 0 is encoded with a definitive midbit transition (orsquare wave phase)

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    - Advantages:

    Required transmission rate is low (bitrate/M)

    Low bandwidth

    Disadvanta es: Low signal to noise ratio (due to multiple

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    -

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    Generate the bit sequence {0,1}. Assume that each bit is

    Implement NRZIm and AMI encoding. Com are the PSD of enerated si nals.

    Decode NRZIm and AMI to source bit.

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    Generate the bit sequence {0,1}. Assume that each bit is

    Implement NRZIs and CMI encoding. Com are the PSD of enerated si nals.

    Decode NRZIs and CMI to source bit.

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    - Generate bit sequence {0,1}

    - , , ,

    Transmit multilevel signal over AWGN channel

    .

    Compare the BER performance of each case.