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-   -   Cisco LRE (LongRangeEthernet) Question (http://www.velocityreviews.com/forums/t34652-cisco-lre-longrangeethernet-question.html)

Kirill Ponazdyr 07-25-2004 10:48 PM

Cisco LRE (LongRangeEthernet) Question
 
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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AnyBody43 07-26-2004 01:20 PM

Re: Cisco LRE (LongRangeEthernet) Question
 
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/extr...-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 12-08-2005 08:58 PM

Re: Cisco LRE (LongRangeEthernet) Question
 
LRE uses one pair of wires ie a phone line.
"AnyBody43" <anybody43@hotmail.com> wrote in message
news:3adc58e4.0407260520.111dd03d@posting.google.c om...
> 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/extr...-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.





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