Brocade switch port offline and in “No light” state with low Tx power

Applies to

Brocade Switch

Issue

• Switch port state shows as No_light under switchshow output:

Index Port Address Media Speed  State    Proto
==============================================
 ----- Truncated -----
   5   5   010500   id     4G   No_Light    FC  

• Portshow of the affected port reports offline status:

portshow 5
portDisableReason: None
portCFlags: 0x0
portFlags: 0x21     PRESENT U_PORT DISABLED
LocalSwcFlags: 0x0
portType:  26.0
portState: 2    Offline  
Protocol: FC
portPhys:  4    No_Light     portScn:   2    Offline   
port generation number:    748
state transition count:    11      

• sfpshow reports Tx value is too low

Slot  5/Port 21:
=============
Identifier:  3    SFP
Connector:   7    LC
Transceiver: 6804404000000000 8,16,32_Gbps M5 sw Short_dist
[...]
Vendor Name: BROCADE
Vendor OUI:  00:05:1e
Vendor PN:   57-1000333-01
Vendor Rev:  A
[...]
Temperature: 59      Centigrade
Current:     7.640   mAmps
Voltage:     3327.1  mVolts
RX Power:    -25.1   dBm (744.6  uW)
TX Power:    -1.3    dBm (4.9 uW)