RX Power low warning ? Is this a big problem

joshhboss · ‎01-12-2022

Hi Everyone, I have 2 switches connected together through a port channel, and i am getting this error in the logs..

SiteOpsOfficeSw204(config-if-range)#
Jan 12 08:03:30.861 EST: %SFF8472-5-THRESHOLD_VIOLATION: Gi1/0/50: Rx power low warning; Operating value: -22.9 dBm, Threshold value: -19.0 dBm.
SiteOpsOfficeSw204(config-if-range)#
SiteOpsOfficeSw204(config-if-range)#
SiteOpsOfficeSw204(config-if-range)#do sh int gig1/0/50
GigabitEthernet1/0/50 is up, line protocol is up (connected) 
  Hardware is Gigabit Ethernet, address is c8f9.f99a.a6b2 (bia c8f9.f99a.a6b2)
  Description: PortChanneltoMain
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseLX SFP
  input flow-control is off, output flow-control is unsupported 
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:10, output 00:00:10, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 1273000 bits/sec, 127 packets/sec
  5 minute output rate 3000 bits/sec, 4 packets/sec
     521914 packets input, 486394285 bytes, 0 no buffer
     Received 79774 broadcasts (77395 multicasts)
     0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 77395 multicast, 0 pause input
     0 input packets with dribble condition detected
     251717 packets output, 28389735 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out
SiteOpsOfficeSw204(config-if-range)#

I have read that this could be a cosmetic error, but i also showed the show interface to see if someone could help me understand if there is anything i should do to resolved this.

balaji.bandi · ‎01-12-2022

1000BaseLX SFP

as i see the SFP here LX,

couple of things we need to check :

1. is this issue you see recently, from the day 1, or is this new link ?

2. do you see any performance issue ? other than logs ?

3. what Mode of cable ? Multi-mode or single mode ?

4. what is the distance between this switch and other end ?

5. what is other end ? switch ? or what device ?

post : (both the sides)

#show inte gig1/0/50 trans det

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joshhboss · ‎01-12-2022

Right now it is connected to a mikrotik CRS328-4C-20S-4S+

im using the mikrotik mainly because of port density.. Im saving up for an asr920 with 24 sfp por4ts

Below are the two commands..

Thank you

SiteOpsOfficeSw204#show int gig1/0/50
GigabitEthernet1/0/50 is up, line protocol is up (connected) 
  Hardware is Gigabit Ethernet, address is c8f9.f99a.a6b2 (bia c8f9.f99a.a6b2)
  Description: PortChanneltoMain
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseLX SFP
  input flow-control is off, output flow-control is unsupported 
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:12, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 37
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 2468000 bits/sec, 453 packets/sec
  5 minute output rate 4347000 bits/sec, 408 packets/sec
     21174785 packets input, 20634037236 bytes, 0 no buffer
     Received 468401 broadcasts (409965 multicasts)
     0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 409965 multicast, 0 pause input
     0 input packets with dribble condition detected
     8475123 packets output, 10929839944 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out
SiteOpsOfficeSw204#show int gig1/0/50 trans de
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)
--------- ------------------  ----------  ---------  ---------  ---------
Gi1/0/50    32.3                90.0        85.0        -5.0      -10.0

                              High Alarm  High Warn  Low Warn   Low Alarm
           Voltage            Threshold   Threshold  Threshold  Threshold
Port       (Volts)            (Volts)     (Volts)    (Volts)    (Volts)
---------  ---------------    ----------  ---------  ---------  ---------
Gi1/0/50   3.31                  3.70        3.60        3.00       2.90

           Optical            High Alarm  High Warn  Low Warn   Low Alarm
           Transmit Power     Threshold   Threshold  Threshold  Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm)      (dBm)
---------  -----------------  ----------  ---------  ---------  ---------
Gi1/0/50    -6.3                 1.0        -3.0        -9.5      -13.5

           Optical            High Alarm  High Warn  Low Warn   Low Alarm
           Receive Power      Threshold   Threshold  Threshold  Threshold
Port       (dBm)              (dBm)       (dBm)      (dBm)      (dBm)
-------    -----------------  ----------  ---------  ---------  ---------
Gi1/0/50   -23.1         --      1.0        -3.0       -19.0      -23.0

joshhboss · ‎01-13-2022

BTW the cable is single mode, and the switch is actually not far away but it is on a premade 1000 ft fiber.

Reza Sharifi · ‎01-12-2022

Hi,

This is a cosmetic error that appears in several different Cisco switches and routers with fiber interfaces. Your interface looks good and clean. Sometimes replacing the SFP, cleaning the fiber connectors helps and sometimes an upgrade will resolve the issue. So, if the message is affecting the interface, open a ticket with Cisco and ask them what could be done.

HTH