Cisco WAN Switching Modules

Field Notice: Watchdog Timeout Causes AUSM or IMATM to Reset

September 19, 2001

Products Affected








The AX-IMATM-8E1/B is supported in the MGX8220 only.


The AX-IMATM-8T1/B is supported in the MGX8220 only.

Problem Description

The AUSM card resets due to a watchdog timeout. No other errors are logged. Customer traffic is interrupted.


Two conditions must be met before the watchdog timeout occurs.

  1. IMA groups are configured on the AUSM or IMATM card.

  2. Statistics collection is enabled on the card.

Note: The AX-IMATM cards are used only on the MGX8220; they are currently not supported on the MGX8230, MGX8250 or MGX8850 systems.

Problem Symptoms

The AUSM resets and interrupts all user traffic. Network users will notice their sessions with remote resources time out or restart, depending on the application in use. Other symptoms include slow response or no response or lack of access to remote resources. Use the command dspcd to see the following telltale symptom of this anomaly.

ModuleSlotNumber: 2
?FunctionModuleState: Active
?FunctionModuleType: AUSM-8T1/B
?FunctionModuleSerialNum: 965652
?FunctionModuleHWRev: ab
?FunctionModuleFWRev: 10.0.20
?FunctionModuleResetReason: WatchDog timeout reset
?LineModuleType: LM-RJ48-8T1
?LineModuleState: Present
?mibVersionNumber: 26
?configChangeTypeBitMap: CardCnfChng, LineCnfChng
?cardIntegratedAlarm: Clear

Note: The phrase "Watchdog timeout reset" above.

Another symptom of this anomaly is that the command dspcderrs on the AUSM or IMATM does not showing any entries related to this reset.

In some instances, the AUSM or IMATM may be reset a second time due to firmware download failure (observed primarily when 1:N Redundancy is configured). In these instances, the telltale "Watchdog timeout reset" will be overwritten by the reset reason "Reset by PXM". Note that the presence of reset reason "Reset by PXM" alone, is not sufficient to prove that the AUSM or IMATM reset due to watchdog timeout, since the PXM may reset service modules for other reasons.

If the network has a Cisco WAN Manager station attached, the following event will also be captured in the trapd log:

...- MGX_NODE function module in 
slot 17 removed;...

This event alone merely indicates that the AUSM or IMATM was either reset or physically removed, or failed completely, and is not sufficient proof of a watchdog timeout.


Upgrade to MGX Release 1.1.34 or MGX8220 Release 5.0.16


To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.



CSCds79660 (registered customers only)

Watchdog timeout reset on AUSM with no cderrs or sw errors

CSCdt33225 (registered customers only)

Watchdog timeout reset on AUSM with no cderrs or sw errors

CSCdu09408 (registered customers only)

Watchdog timeout reset on AUSM with no cderrs or sw errors. (Although the title states AUSM, this bug applies to the IMATM.)

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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