Brocade switch port offline and in “No light” state with Rx/Tx power showing as -inf

Applies to

Brocade Switch

Issue

• Switch port shows No_light under switchshow output for F port or ISL port:

Index Port Address Media Speed  State    Proto
==============================================
   5   5   0xx500   id     4G   No_Light    FC Disabled  

• porterrshow indicates link fail and loss sig errors

/fabos/cliexec/porterrshow :
          frames        enc     crc     crc     too     too     bad     enc    disc    link    loss    loss    frjt    fbsy     c3timeout     pcs      uncor
        tx       rx      in     err     g_eof   shrt    long    eof     out    c3      fail    sync    sig                      tx      rx      err     err
  65:    5.4g    9.4g    0       0       0       0       0       0       0       0       1       0       1       0       0       0       0       0       0

• 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 Rx stat as -inf.

Slot  3/Port 42:
=============
Identifier:  3    SFP
Connector:   7    LC
[...]
Vendor Name: BROCADE
Vendor OUI:  00:05:1e
Vendor PN:   57-1000333-01
Vendor Rev:  A
[...]
Temperature: 53      Centigrade
Current:     7.496   mAmps
Voltage:     3312.0  mVolts
RX Power:    -inf    dBm (0.0  uW)
TX Power:    -0.3    dBm (924.1 uW)

• sfpshow reports Tx stats as -inf.

Slot  9/Port  1:
=============
Identifier:  3    SFP
Connector:   7    LC
[...]
Vendor Name: BROCADE
Vendor OUI:  00:05:1e
Vendor PN:   57-1000333-01
Vendor Rev:  A
[..]
Temperature: 43      Centigrade
Current:     0.000   mAmps
Voltage:     3313.0  mVolts
RX Power:    -0.6    dBm (880.7uW)
TX Power:    -inf    dBm (0.0   uW)

• fabriclog indicates that port flapped and went offline

Switch 0; Wed Aug 16 12:15:31 2023 GMT (GMT+0:00)
12:15:31.681477 SCN LR_PORT(0);g=0x0                        D2,P0  D2,P0  27    NA    
12:15:31.695830 SCN Port Online; g=0x0,isolated=0           D2,P0  D2,P1  27    NA    
12:15:31.696439 Port Elp engaged                            D2,P1  D2,P0  27    NA    
12:15:31.696468 *Removing all nodes from port               D2,P0  D2,P0  27    NA    
12:15:31.696612 SCN Port F_PORT                             D2,P1  D2,P0  27    NA    
12:15:53.257221 SCN Port Offline;rsn=0x1,g=0x4a             D2,P0  D2,P0  27    NA    
12:15:53.257228 *Removing all nodes from port               D2,P0  D2,P0  27    NA    

• Portshow shows  invalid crc threshold
  portshow 3
portDisableReason: Port Decommissioned, Invalid CRC threshold exceeded
portCFlags: 0x0
portFlags: 0x4021 PRESENT U_PORT DISABLED LED LocalSwcFlags: 0x0 portType: 26.0
portState: Persistently Disabled Protocol: FC
portPhys: 5 No_Sync
portScn: 2 Offline port generation number: 82 state transition count: 82"
• Flapping is observed on both switches for ISL ports.
• For ISL port end device switch Rx and Tx values can be verified for fault isolation.
• Errdump on the switch may log the following:  2024/11/16-12:18:16 (IST), [PORT-1003], 126304, FID 128 | PORT 0/31, WARNING, Switch2, Port 31 Faulted because of many Link Failures.