Persistent PCS Errors and Low RX Power on Switch Port due to bad HBA

• Brocade SAN Switches:  v9.1.1c3

• PCS errors observed on switch ports:

/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
  214:    1       1       0       0       0       0       0       0       0       0       0       0       0       0       0       0       0      81.8k    0

• Low RX power reported: 

=============
Slot 10/Port 22:
=============
RX Power:    -8.0    dBm (156.80uW)
TX Power:    -1.1    dBm (784.30 uW)

• Port Flapping:


Switch 0; Sat Oct 11 00:03:23 2025 IST (GMT+5:30)
00:26:09.540109 SCN LR_PORT(0);g=0x16c6                     A2,P0  A2,P0  214   NA    
00:26:09.588683 SCN Port Online; g=0x16c6,isolated=0        A2,P0  A2,P1  214   NA    
00:26:09.588901 Port Elp engaged                            A2,P1  A2,P0  214   NA    
00:26:09.588916 *Removing all nodes from port               A2,P0  A2,P0  214   NA    
00:26:09.589118 SCN Port F_PORT                             A2,P1  A2,P0  214   NA

• Alternatively, we can plug into a known good device for fault isolation of cable and sfp by following below steps:
  • In order to do fault isolation if the hardware, move the cable to next available port on the switch end and observe for any increments:
  • If the issues follows on new port, replace the cable/patch panel and verify the port counters
  • If the issue does not follow to the new port, then swap the SFP of the affected port with a good known working SFP and see if the errors subside

• Post SFP replacement on the switch and Patch panel replacement the issue still persists.

• Proceed to the solution if the above isolation steps does not help to resolve the issue.