Brocade switch port offline and in “No light” state with Rx power low/-inf due to faulty end device hardware

Applies to

Brocade Switch

Issue

• Switch port flapped and 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 Rx 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 (3.1  uW)
TX Power:    -1.3    dBm (743.9 uW)

• sfpshow reports Rx to be -inf

=============
Slot  4/Port  6:
=============
Identifier:  3    SFP
Connector:   7    LC
Transceiver: 6804406000000000 8,16,32_Gbps M5 sw Inter,Short_dist
..
Vendor Name: BROCADE
Vendor OUI:  00:05:1e
Vendor PN:   57-1000485-01
Vendor Rev:  B
Wavelength:  850  (units nm)
...
O-Wrap Control: 0
..
Current:     7.496   mAmps
Voltage:     3274.5  mVolts
RX Power:    -inf    dBm (0.0  uW)
TX Power:    -1.0    dBm (798.8 uW)

• porterrshow reported linkfail, loss sig and pcs error

/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
  22:    5.1g    1.2g    0       0       0       0       0       0       0       0      12       0      16       0       0       0       0      21       3

• LR_OUT error reported in  sshow_fabric logs:

23:32:24.171xx4 SCN AC_PORT g=0xxc8 LR_OUT                  A2,P2  A2,P3  22    NA
23:32:24.17xx48 *Snd port state: P3                         A2,P3  A2,P3  22    NA
23:32:24.25xx29 *Snd port state: P0                         A2,P0  A2,P0  22    NA

• Cable check and SFP replaced on the switch, issue still persists
• The switch may log the following error in errdump as well
  2024/06/24-10:13:18 (IST), [MAPS-1003], 754746, SLOT 1 | FID 128 | PORT 9/19, WARNING, NTTC_X6_108_FAB2, slot9 port19-H.LIN.HBCNBMOBPJS1.10.227.204.78.JZ6KPT3.HBCNBMOBPJ, U-Port 9/19, Condition=ALL_PORTS(LOSS_SIGNAL/min>3), Current Value:[LOSS_SIGNAL, 19 LOS], RuleName=defALL_PORTSLOSS_SIGNAL_3, Dashboard Category=Port Health, Quiet Time=None.