Cisco MDS 9000 Series Configuration Manual page 166

Information About Congestion Detection
• Display of average Tx credit not available in 100-ms intervals—Cisco MDS switches have a software
Cisco MDS 9000 Series Interfaces Configuration Guide, Release 8.x
148
The following information is displayed in the logging onboard TxWait and RxWait:
• Delta TxWait ticks—Each tick represents 2.5 microseconds. Because the minimum value
logged is the equivalent of 100 ms, the minimum value that is displayed in the output is 40,000.
• Delta TxWait in seconds—TxWait value that is multiplied by 2.5 and then divided by 1,000,000
results in the TxWait value, in seconds. The TxWait value is displayed as an integer in the
output. Therefore, TxWait value less than 1 second is displayed as 0.
• Congestion Percentage (%)—TxWait value that is divided by 20 results in TxWait, in seconds.
This value gives a quick way of seeing how the congestion was in the 20-second interval.
• Timestamp—Indicates the date and time at the end of a 20-second interval when the delta
TxWait was determined.
switch# show logging onboard txwait module 9
---------------------------------
Module: 9 txwait count
---------------------------------
----------------------------
Show Clock
----------------------------
2018-08-28 10:08:07
---------------------------------
Module: 9 txwait
---------------------------------
Notes:
- Sampling period is 20 seconds
- Only txwait delta >= 100 ms are logged
-----------------------------------------------------------------------------
| Interface | Delta TxWait Time
| | 2.5us ticks | seconds |
-----------------------------------------------------------------------------
| fc9/17 | 1555381
| fc9/17 | 8000000
| fc9/17 | 8000000
| fc9/17 | 8000000
| fc9/17 | 7236463
| fc9/17 | 1059481
process that runs every 100 ms to check for ports that are in continuous state of 0 Tx credits
remaining. The ports that are in the continuous state of 0 Tx credits are displayed in the output of
the show system internal snmp credit-not-available [module module] and show logging onboard
error-stats commands. These commands display 100 ms, 200 ms, or more of continuous state of
0 Tx credits remaining.
The show system internal snmp credit-not-available [module module] command shows the Tx
Credit Not Available alerts from port monitor. The alerts are in 100-ms intervals, as a percentage,
of the configured port-monitor polling interval. If the Tx Credit Not Available (tx-credit-not-available)
port-monitor counter is not configured in the active policy, no events are displayed.
Congestion Detection, Avoidance, and Isolation
| Congestion | Timestamp
|
| 3 | 19% | Thu Aug
| 20 | 100% | Thu Aug
| 20 | 100% | Thu Aug
| 20 | 100% | Thu Aug
| 18 | 90% | Thu Aug
| 2 | 13% | Thu Aug
|
|
2 11:49:39 2018 |
2 11:49:19 2018 |
2 11:48:59 2018 |
2 11:48:38 2018 |
2 11:48:18 2018 |
2 11:47:58 2018 |