Field Notice: FN - 70278 - Some Cisco vEdge-2000 Routers Report Spurious DRAM Temperature Sensor Alarms - Replace on Failure

Notice

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Revision History

Revision	Publish Date	Comments
1.0	28-Sep-18	Initial Release
1.1	16-Mar-21	Updated the Workaround/Solution Section and Removed the Upgrade Program Section

Products Affected

Affected Product ID	Comments
VEDGE-2000-AC-K9=
VEDGE-2000-AC-K9

Defect Information

Defect ID	Headline
CSCvk51236	Axiom DIMM Issue

Problem Description

Some Cisco vEdge-2000 routers might report spurious DRAM temperature sensor alarm messages on the console and in the hardware error logs. Affected routers report a "DRAM temperature sensor failed" log message when there is, in fact, no DRAM operating temperature problem and no failed sensor. These spurious alarms are also reported to vManage and thus might become a source of distraction during operation.

Background

Cisco vEdge-2000 Series router software includes logic to collect environment sensor data from various hardware components. The software uses that data for reporting and for system management purposes, which include the creation of log message warnings for sensor readings that are outside of an acceptable range. One of the readings collected is from the temperature sensor in the memory DIMMs. In 2018, a batch of vEdge-2000 routers was manufactured with memory DIMMs that do not implement the temperature sensor and thus do not provide a sensor reading to the software. vEdge software interprets the missing temperature reading on these affected routers to be a hardware error when, in fact, the hardware functions normally.

Problem Symptom

Affected vEdge routers generate DRAM temperature hardware alarms after bootup. In order to view hardware alarms, enter the CLI command show hardware alarms or show hardware environment on the router console or remotely via vManage. Affected routers display a "DRAM temperature sensor failed" alarm in the CLI output as shown in this example.

show hardware alarms
 
hardware alarms 1 8
alarm-name        "Temperature Fault"
alarm-time        "Thu Jun 14 14:22:10 UTC 2018"
alarm-category    Critical
alarm-description "DRAM temperature sensor failed"
hardware alarms 1 9
alarm-name        "Temperature Fault"
alarm-time        "Thu Jun 14 14:22:10 UTC 2018"
alarm-category    Critical
alarm-description "DRAM temperature sensor failed"

Affected vEdge routers also display a "Failed" status for DRAM 0 and DRAM 1 in the show hardware environment CLI output as shown in this example.

show hardware environment
 
hardware environment "Temperature Sensors" PIM 1
status      OK
measurement "33 degrees C/91 degrees F"
hardware environment "Temperature Sensors" DRAM 0
status      Failed
measurement "0 degrees C/32 degrees F"
hardware environment "Temperature Sensors" DRAM 1
status      Failed
measurement "0 degrees C/32 degrees F"
hardware environment "Temperature Sensors" Board 0
status      OK
measurement "30 degrees C/86 degrees F"
hardware environment "Temperature Sensors" Board 1
status      OK
measurement "34 degrees C/93 degrees F"
hardware environment "Temperature Sensors" Board 2
status      OK
measurement "34 degrees C/93 degrees F"
hardware environment "Temperature Sensors" Board 3
status      OK
measurement "34 degrees C/93 degrees F"
hardware environment "Temperature Sensors" "CPU junction" 0
status      OK
measurement "45 degrees C/113 degrees F"
hardware environment Fans "Tray 0 fan" 0
status      OK
measurement "Spinning at 5726 RPM"
hardware environment Fans "Tray 0 fan" 1
status      OK
measurement "Spinning at 3724 RPM"
hardware environment Fans "Tray 1 fan" 0
status      OK
measurement "Spinning at 5684 RPM"
hardware environment Fans "Tray 1 fan" 1
status      OK
measurement "Spinning at 3547 RPM"
hardware environment Fans "Tray 2 fan" 0
status      OK
measurement "Spinning at 5781 RPM" 
hardware environment Fans "Tray 2 fan" 1 
status      OK 
measurement "Spinning at 3504 RPM" 
hardware environment Fans "Tray 3 fan" 0 
status      OK 
measurement "Spinning at 5666 RPM" 
hardware environment Fans "Tray 3 fan" 1 
status      OK 
measurement "Spinning at 3816 RPM" 
hardware environment PEM "Power supply" 0 
status      OK 
measurement "Powered On: yes; Fault: no; Status: Power in: 35W out 26W, Fan: 4416 RPM" 
hardware environment PEM "Power supply" 1 
status      OK 
measurement "Powered On: yes; Fault: no; Status: Power in: 43W out 33W, Fan: 4416 RPM" 
hardware environment PIM "Interface module" 1 
status      OK 
measurement "Present: yes; Powered On: yes; Fault: no"

Affected vEdge routers also report temperature sensor failure alerts in vManage as shown in this example.

Workaround/Solution

Since the DRAM temperature sensor failure alarms are essentially spurious on affected vEdge routers, the easiest workaround is to simply ignore or filter those alarms. The missing DRAM sensors pose no material impact to the operation of the router. Other ambient temperature sensors in the router continue to function and monitor the thermal operations normally.

There is no software fix for this problem. However, customers who deem it essential to eliminate the source of the alarm should request a Return Material Authorization (RMA) through the normal support process for Fix on Failure.

Note: Retain any accessories, which include the power cord and console cable, from the original unit since replacement units might not include those items.

How To Identify Affected Products

For vEdge routers that are deployed or otherwise accessible in an operating state, use the console or vManage in order to obtain the output of either the show hardware alarms or the show hardware environment CLI command and look for the failure described previously.

Alternatively, you can enter the serial numer in the Serial Number Validation Tool page. The serial number of a vEdge router can be located with one of these methods:

• In vManage, choose Configuration > Devices. The device table lists the serial and model numbers of the routers in the network.
• Enter the show hardware inventory command at the CLI prompt.
• Review the label on the right side of the router in order to determine the serial number.

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:

• Open a service request on Cisco.com
• By email
• By telephone

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