[c-nsp] Optical - rx power low warning

[Erik Klaassen]

your loss over 20mile is a bit high.
Assuming the other side is also sending at 2.4dbm, you receive -16.4 so your loss is 18.8.

20Mile is ~ 35 km. according to g652 standand loss @1550 should be 0.21dbm per km. So that would be 7,35.
Add a cwdm mux/demux on both side is around 4dbm (2 per side), add some patches 2dbm (0.5 per patch). Total loss should be around 13.3

What is your rx power at the other side?

cheers, 

Erik 



----- Oorspronkelijk bericht -----
Van: "Mike" <mike-cisconsplist at tiedyenetworks.com>
Aan: cisco-nsp at puck.nether.net
Verzonden: Donderdag 30 april 2015 08:08:23
Onderwerp: [c-nsp] Optical - rx power low warning

I am bringing up a new link. This is on CWDM fiber with a supposedly 
80km optic. Path is about 20 miles. I'm getting the following warning 
messages:

*Apr 29 2015 22:29:09.851 PST: %SFF8472-3-THRESHOLD_VIOLATION: Te0/3: Rx 
power low warning; Operating value: -16.4 dBm, Threshold value: -15.8 dBm.

The link is working fine without issue but I want to know what I'm 
looking at and wether it's worthwhile to do something about it?

Also in my show inventory for this I get:

NAME: "TenGigabitEthernet0/3", DESCR: "10GBASE-ER/EW"
PID: scrambled gobblydegook  VID: scrambled 
crap , SN: INEAC0060007


     The 'pid' and 'vid' values are all high bit chars undecipherable. 
Lastly, Im including the detail output in case any of these numbers make 
sense:

sh int te0/3 transceiver
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
If device is externally calibrated, only calibrated values are printed.
++ : high alarm, +  : high warning, -  : low warning, -- : low alarm.
NA or N/A: not applicable, Tx: transmit, Rx: receive.
mA: milliamperes, dBm: decibels (milliwatts).

                                            Optical   Optical
            Temperature  Voltage  Current   Tx Power  Rx Power
Port       (Celsius)    (Volts)  (mA)      (dBm)     (dBm)
---------  -----------  -------  --------  --------  --------
Te0/3        34.1       0.00      91.5       2.4     -16.4 -

sh int te0/3 transceiver detail

ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
mA: milliamperes, dBm: decibels (milliwatts), NA or N/A: not applicable.
++ : high alarm, +  : high warning, -  : low warning, -- : low alarm.
A2D readouts (if they differ), are reported in parentheses.
The threshold values are calibrated.

                               High Alarm  High Warn  Low Warn   Low Alarm
            Temperature        Threshold   Threshold  Threshold Threshold
Port       (Celsius)          (Celsius)   (Celsius)  (Celsius) (Celsius)
---------  -----------------  ----------  ---------  --------- ---------
Te0/3        34.1                   74.0       70.0        0.0 -4.0

                               High Alarm  High Warn  Low Warn   Low Alarm
            Voltage            Threshold   Threshold  Threshold Threshold
Port       (Volts)            (Volts)     (Volts)    (Volts) (Volts)
---------  -----------------  ----------  ---------  --------- ---------
Te0/3        0.00                    N/A        N/A N/A        N/A

                               High Alarm  High Warn  Low Warn   Low Alarm
            Current            Threshold   Threshold  Threshold Threshold
Port       (milliamperes)     (mA)        (mA)       (mA)       (mA)
---------  -----------------  ----------  ---------  --------- ---------
Te0/3        91.5                    N/A        N/A N/A        N/A

            Optical            High Alarm  High Warn  Low Warn   Low Alarm
            Transmit Power     Threshold   Threshold  Threshold Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm) (dBm)
---------  -----------------  ----------  ---------  --------- ---------
Te0/3         2.4                    6.9        3.9       -4.7 -7.7

            Optical            High Alarm  High Warn  Low Warn   Low Alarm
            Receive Power      Threshold   Threshold  Threshold Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm) (dBm)
---------  -----------------  ----------  ---------  --------- ---------
Te0/3       -16.4         -          1.9       -1.0      -15.8 -18.8


Thanks.

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