Cisco LRE (LongRangeEthernet) Question

Discussion in 'Cisco' started by Kirill Ponazdyr, Jul 25, 2004.

  1. Hi folks,

    We are trying to replace the SDSL link between two locations with
    Cisco LRE using WS-C2924-LRE-XL switch combined with 575 CPE.

    In theory, the cabling should be suifficient enough to support LRE-5
    link (~1km dry copper pair).

    Unfortunately we cannot get link up, we are 100% sure that this is not
    error in cabling. Also, both devices communicate excellently in a lab
    condition.

    Doing the "show controllers lre status link lo0/1" yelds

    Port Link SNR RS Errs CPE-Tx Sw-AGC-Gain Interleaver
    PMD-S
    (dB) (dBm/Hz) (dB) Rx-Bsz Tx-Bsz
    ------ ---- ---- ----------- -------- ----------- -------------
    -----
    Lo0/1 DOWN 0 0 0.0 0.0 16 0
    0x84

    The only visible difference seen between the unplugged port and port
    connected to the leased line is the changing state of "PMD-S". When
    Switch is not connected to the wall jack it shows 0x04, when connected
    it will display 0x84

    Unfortunately the Cisco documentation is very dry about this field, it
    only claims that this is "Physical Media Device Status field used for
    Diagnostics".

    Does anyone knows what the codes in this field mean?

    Are there any other useful diagnostics and troubleshooting procedures
    we could perform to find our the reason for not receiving the signal?

    Best Regards

    Kirill
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    Kirill Ponazdyr, Jul 25, 2004
    #1
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  2. Kirill Ponazdyr

    AnyBody43 Guest

    Kirill Ponazdyr <ng1@@codeangels.com>
    > we are 100% sure that this is not
    > error in cabling. Also, both devices communicate excellently in a lab
    > condition.


    To my mind this demonstrates that there is indeed a cabling issue.

    Still I know nothing of LRE, maybe it uses the cable differently.

    > Doing the "show controllers lre status link lo0/1" yelds
    >
    > Port Link SNR RS Errs CPE-Tx Sw-AGC-Gain Interleaver
    > PMD-S
    > (dB) (dBm/Hz) (dB) Rx-Bsz Tx-Bsz
    > ------ ---- ---- ----------- -------- ----------- -------------
    > -----
    > Lo0/1 DOWN 0 0 0.0 0.0 16 0
    > 0x84
    >
    > The only visible difference seen between the unplugged port and port
    > connected to the leased line is the changing state of "PMD-S". When
    > Switch is not connected to the wall jack it shows 0x04, when connected
    > it will display 0x84


    Google for [802.3ah pmd status] says:

    http://www.icir.org/fenner/mibs/extracted/EFM-CU-MIB-hubmib-00.txt

    There seem to be two possibly relevant sections but both agree:


    You appear to have

    4 lossOfSignal - one or more PMIs in the aggregation group
    indicate Loss of Signal
    8 snrMgnRemoteDefect(7), -- Remote SNR Margin Violation


    i.e. A cable fault.

    I am doing a LOT of guessing here however I can find no inconsistencies
    with the view that it is most likely a cable fault.
     
    AnyBody43, Jul 26, 2004
    #2
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  3. Kirill Ponazdyr

    Larry Jones Guest

    LRE uses one pair of wires ie a phone line.
    "AnyBody43" <> wrote in message
    news:...
    > Kirill Ponazdyr <ng1@@codeangels.com>
    >> we are 100% sure that this is not
    >> error in cabling. Also, both devices communicate excellently in a lab
    >> condition.

    >
    > To my mind this demonstrates that there is indeed a cabling issue.
    >
    > Still I know nothing of LRE, maybe it uses the cable differently.
    >
    >> Doing the "show controllers lre status link lo0/1" yelds
    >>
    >> Port Link SNR RS Errs CPE-Tx Sw-AGC-Gain Interleaver
    >> PMD-S
    >> (dB) (dBm/Hz) (dB) Rx-Bsz Tx-Bsz
    >> ------ ---- ---- ----------- -------- ----------- -------------
    >> -----
    >> Lo0/1 DOWN 0 0 0.0 0.0 16 0
    >> 0x84
    >>
    >> The only visible difference seen between the unplugged port and port
    >> connected to the leased line is the changing state of "PMD-S". When
    >> Switch is not connected to the wall jack it shows 0x04, when connected
    >> it will display 0x84

    >
    > Google for [802.3ah pmd status] says:
    >
    > http://www.icir.org/fenner/mibs/extracted/EFM-CU-MIB-hubmib-00.txt
    >
    > There seem to be two possibly relevant sections but both agree:
    >
    >
    > You appear to have
    >
    > 4 lossOfSignal - one or more PMIs in the aggregation
    > group
    > indicate Loss of Signal
    > 8 snrMgnRemoteDefect(7), -- Remote SNR Margin Violation
    >
    >
    > i.e. A cable fault.
    >
    > I am doing a LOT of guessing here however I can find no inconsistencies
    > with the view that it is most likely a cable fault.
     
    Larry Jones, Dec 8, 2005
    #3
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