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Cisco Bug: CSCul37308 - Rx power is seen on peer when Tx power is off on 3850

Last Modified

Sep 01, 2020

Products (1)

  • Cisco Catalyst 3850 Series Switches

Known Affected Releases

15.0(1)EZ 16.1(0)

Description (partial)

Symptom:
When admin shutdown G1/1/1 or G1/1/2 on 3850, we can see Tx power is off on 3850 by "show inter trans" CLI.
However, SFP laser has not turned off (RED laser) on 3850, and Rx power is seen on peer by "show inter trans".

3560-1#show cdp ne
 
Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
3850-1
                 Gig 0/49          162              S I   WS-C3850- Gig 1/1/1

3560-1#show inter g0/49 trans
ITU Channel not available (Wavelength not available),
Transceiver is externally 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  Tx Power  Rx Power
Port       (Celsius)    (Volts)  (dBm)     (dBm)
---------  -----------  -------  --------  --------
Gi0/49       28.1       3.32      -5.5      -3.9<<<<   
 
3560-1#
*Mar  6 04:12:09.302: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
*Mar  6 04:12:10.300: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/49, changed state to down
*Mar  6 04:12:11.307: %LINK-3-UPDOWN: Interface GigabitEthernet0/49, changed state to down
3560-1#
3560-1#show inter g0/49 trans
ITU Channel not available (Wavelength not available),
Transceiver is externally 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  Tx Power  Rx Power
Port       (Celsius)    (Volts)  (dBm)     (dBm)
---------  -----------  -------  --------  --------
Gi0/49       28.7       3.32      -5.5      -4.0 <<<<<<<

Conditions:
topology:
3850 G1/1/1-----------G0/49 3560

When use C3850-NM-2-10G, the issue will happen.
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