Connectrix: Cisco MDS Multiple interfaces dropping frames causing serve performance issue

Summary: Multiple interfaces dropping frames causing serve performance issue

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Symptoms

Multiple interfaces dropping frames causing serve performance issue to customers environment..

MDS switch logging the following PMON alerts:-

logging log:
PMON-SLOT1-3-RISING_THRESHOLD_REACHED: Credit Loss Reco has reached the rising threshold 
PMON-SLOT1-3-RISING_THRESHOLD_REACHED: TX Credit Not Available has reached the rising threshold 
 

Cause

Onboard Logging log review:

The following IPA errors indicate packets are being corrupted after being received.  The module these are occurring on should be replaced
`show hardware internal errors`
|------------------------------------------------------------------------|
| Device:Tbird Que Driver         Role:QUE      Mod: 1    |
| Device Statistics Category :: ERROR
|------------------------------------------------------------------------|
Instance:0
Cntr  Name                                          Value             Ports
----- ----                                          -----             ----- 
   24 THB_IPA_IPA0_CNT_BAD_CRC                      0000000000637620  1-4 - 
   25 THB_IPA_IPA0_CNT_CORRUPT                      0000000000637620  1-4 - 


The following  EBM errors are the same corrupted packets being received at the egress linecard. These will likely occur on several modules that are receiving these corrupted packets. These modules are not faulty. Replace the module generating the IPA errors and these will stop:
`show hardware internal errors`
|------------------------------------------------------------------------|
| Device:Tbird Fwd Driver         Role:L2          Mod: 2    |
| Device Statistics Category :: ERROR
|------------------------------------------------------------------------|
Instance:1
Cntr  Name                                          Value             Ports
----- ----                                          -----             -----
  300 THB_EBM0_ACC_ERR_QUEUE_DROP_PKT               0000000000000017  9-12 -   <--------
  301 THB_EBM0_CNT_ERR_QUEUE_DROP_SF                0000000000000010  9-12 -     <--------
13414 TBIRD_FWD_EBM_0_PACK0_EPR_DROP                0000000000000001  9-12 - 
13422 TBIRD_FWD_EBM_0_PACK1_EPR_DROP                0000000000000005  9-12 - 
13430 TBIRD_FWD_EBM_0_PACK2_EPR_DROP                0000000000000001  9-12 - 
13438 TBIRD_FWD_EBM_0_PACK3_EPR_DROP                0000000000000003  9-12 - 
13727 TBIRD_FWD_EPR0_PKT_CRC_ERR                    0000000000000001  9-16 - 
13755 TBIRD_FWD_EPR1_PKT_CRC_ERR                    0000000000000005  9-16 - 
13783 TBIRD_FWD_EPR2_PKT_CRC_ERR                    0000000000000001  9-16 - 
13811 TBIRD_FWD_EPR3_PKT_CRC_ERR                    0000000000000003  9-16 - 

|------------------------------------------------------------------------|
| Device:Tbird Fwd Driver         Role:L2          Mod: 3    |
| Device Statistics Category :: ERROR
|------------------------------------------------------------------------|
Instance:2
Cntr  Name                                          Value             Ports
----- ----                                          -----             -----
  300 THB_EBM0_ACC_ERR_QUEUE_DROP_PKT               0000000000068016  17-20 - 
  301 THB_EBM0_CNT_ERR_QUEUE_DROP_SF                0000000000057196  17-20 - 

|------------------------------------------------------------------------|
| Device:Tbird Fwd Driver         Role:L2          Mod: 4    |
| Device Statistics Category :: ERROR
|------------------------------------------------------------------------|
Instance:0
Cntr  Name                                          Value             Ports
----- ----                                          -----             -----
  300 THB_EBM0_ACC_ERR_QUEUE_DROP_PKT               0000000000004504  1-4 - 
  301 THB_EBM0_CNT_ERR_QUEUE_DROP_SF                0000000000003598  1-4 - 

|------------------------------------------------------------------------|
| Device:Tbird Fwd Driver         Role:L2          Mod: 5    |
| Device Statistics Category :: ERROR
|------------------------------------------------------------------------|
  300 THB_EBM0_ACC_ERR_QUEUE_DROP_PKT               0000000000020069  1-4 - 
  301 THB_EBM0_CNT_ERR_QUEUE_DROP_SF                0000000000019715  1-4 -  

The EBM errors are the same corrupted packets being received at the egress linecard. These will likely occur on several modules that are receiving these corrupted packets. These modules are not faulty. Replace the module generating the IPA errors and these will stop:

Occurs on MDS DS-X9232-256K9 and DS-X9248-256K9 modules only.

Resolution

Fix:
Replace the linecard logging the following errors:
THB_IPA_IPA0_CNT_BAD_CRC                     
THB_IPA_IPA0_CNT_CORRUPT     

Note: port-monitor has 3 special counters that can alert on the above condition. Since the default "slowdrain" policy are mostly used these are not monitored .
The counters are:

 err-pkt-from-port
 err-pkt-to-xbar
 err-pkt-from-xbar   

See also for additional information :
CSCum09652   Add Gen4 IPA and EFI errors to port-monitor xbar errors
          

Products

Connectrix MDS-9513
Article Properties
Article Number: 000167497
Article Type: Solution
Last Modified: 23 Oct 2025
Version:  5
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