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Data Center Expert | Troubleshooting SNMP Lost Communication to Third Party Devices

Published date: 27 August 2019

Issue
Troubleshooting SNMP communications issues between Data Center Expert and Third-Party devices.

Product Line
StruxureWare Data Center Expert (DCE)
     - Basic Appliance (AP9465)
     - Standard Appliance (AP9470)
     - Enterprise Appliance (AP9475)
     - Virtual Appliance (AP94VMACT)
StruxureWare Central (SWC)
InfraStruXure Central (ISXC)

Environment
StruxureWare Data Center Expert (all versions)
StruxureWare Central (all versions)
InfraStruXure Central (all versions)
Third-Party Devices that support SNMPv1 or SNMPv3
APC Devices that use a Non-Conventional APC Network Management Card


Cause
There are a number of reasons StruxureWare Data Center Expert (DCE) may not be able to communicate with a device.  Lost communication usually occurs due to incorrect SNMP settings or SNMP being blocked on the network between the server and the APC device.


Resolution:

The steps below will help resolve lost communication issues to devices.  For most APC devices, resolution steps can be found within knowledge base FA226273.  If you do not know if the device is APC or Third-party, proceed below to determine.
Determining if your Device is APC or Third-Party

1) Log into the DCE Desktop Client using an Administrator account.

2) Navigate to the Monitoring perspective (button) and select the device group in the left-pane that contains the device in lost communication.

3) Right-click on the device within the Device View pane (tab).
     - If there is an option for "APC SNMP Device Configuration..." navigate to knowledge base FA226273.
     - If there is no option for "APC SNMP Device Configuration..." proceed to SNMP Lost Communication Troubleshooting.
SNMP Lost Communication Troubleshooting

1) Within the Device View pane take note of the IP Address of the device that is in lost communication.

2) Navigate to: Device Menu > SNMP Device Communication Settings > Device Scan Settings.

3) Search for the Device's IP Address and then look within the Protocol column for that device to determine SNMP version.

4) If the device is in intermittent lost communication, proceed to step 5.  If the device is in persistent lost communication, proceed to step 6.
NOTE: Intermittent lost communication is when the device loses communication to DCE and then re-establishes communication multiple times.
NOTE: Persistent lost communication is when a lost communication alert for the device is constant within DCE and is not clearing and reoccurring.

5) Intermittent lost communication occurs when DCE does not receive a response back for the SNMP request to the device within a set timeframe.  This usually occurs due to network traffic issues or end-device processing issues.  The usual resolution to this issue is to increase timeouts and retries for communication before DCE will report a lost communication alarm:
     a) Check the box next to the device searched for in step 3.
     b) Click the Edit Device Scan Settings... button.
     c) Increase the Timeouts (seconds) and Retries.
     NOTE: If having regular intermittent lost communications, it is recommended to increase the values to 10 second Timeouts and 5 Retries.  Note that this will delay any lost communication alarms until all of the timeouts and retries have completed.
     d) Click OK to save the changes.

     NOTE: If the issue returns after increasing the timeouts and retries, the issue is commonly network related or end-device related.  Contact your network team and/or technical support for assistance.

6) Persistent lost communication to devices occurs when DCE does not receive any responses back to SNMP requests to the APC Device.  This usually occurs due to incorrect SNMP Settings within DCE or the Device.  This may also occur due to changes on the network that may block the SNMP traffic from DCE to the device or from the device to DCE.  If your device uses SNMPv1 as determined in step 3, proceed to SNMPv1 Persistent Lost Communication Troubleshooting.  If your device is using SNMPv3, as determined in step 3, proceed to SNMPv3 Persistent Lost Communication Troubleshooting.
SNMPv1 Persistent Lost Communication Troubleshooting

1) Navigate to the Monitoring perspective and select the device group that has the device in lost communication.

2) Right-click on the device within the Device View pane and select Launch to Device.  This will load the web interface of the device.

3) Log into the web interface and verify that SNMPv1 is enabled, community strings are correct, and any other restrictions are set appropriately.
NOTE: Consult documentation for the third-party device to determine how to adjust the SNMPv1 settings.

4) Data Center Expert only requires the ability to Read (Get) data for third-party devices.  Ensure that Read access is enabled for the community string applicable to DCE SNMPv1 communication and take note of it for use in step 6.

5) DCE Desktop Client > Device > SNMP Device Communication Settings > Device Scan Settings > Search for device > Check Box on device line item > Edit Device Scan Settings.

6) The community string recorded in step 4 should match. If it does not match, either the community string within the Device Scan Settings or the community string within the device must be updated.
NOTE: Updating the community string on the device may cause interference with any other tools that are also using that community string to communicate to the device over SNMP.

7) If the community strings match, increase the timeouts to 10 seconds and retries to 5.  This will allow the device additional time to respond before DCE reports a lost communication with the device.

8) If the device is still in lost communication, contact your local technical support for assistance.
SNMPv3 Persistent Lost Communication Troubleshooting

1) Navigate to the Monitoring perspective and select the device group that has the device in lost communication.

2) Right-click on the device within the Device View pane and select Launch to Device.  This will load the web interface of the device.

3) Log into the web interface and verify/record: SNMPv3 is enabled, SNMPv3 User Name is entered, SNMPv3 Authentication Passphrase, Authentication Protocol, Privacy Passphrase, and Privacy Protocol.
NOTE: Consult documentation for the third-party device to determine how to adjust the SNMPv3 settings.

4) DCE Desktop Client > Device > SNMP Device Communication Settings > Device Scan Settings > Search for device > Check Box on device line item > Edit Device Scan Settings.

5) The SNMPv3 settings recorded in step 4 should match what DCE has within the Device Scan Settings of the device. If it does not match, update the SNMPv3 settings within DCE's Device Scan Settings for the device, or on the device itself, depending on which is incorrect.
NOTE: Updating settings on the device may cause interference with any other tools that are also using those settings to communicate to the device over SNMP.

6) If the settings match, increase the timeouts to 10 seconds and retries to 5.  This will allow the device additional time to respond before DCE reports a lost communication with the device.

STOP!  Navigate to the DCE Desktop Client and click on the Monitoring perspective.  Select the device group that contains the device in lost communication.  Right-click on the device within the device-view pane and select Request Device Scan.  If the lost communication alarm does not clear after one (1) minute, proceed to step 7.

7) If the device is still in lost communication, simplify the settings, for troubleshooting only, to:
     - User Name: DataCenterExpert
     - Authentication Passphrase: DataCenterExpert
     - Privacy Passphrase: DataCenterExpert
     - Authentication Protocol: None
     - Privacy Protocol: None

8) Change the Device Scan Settings within DCE to match the new settings on the NMC, set in step 7.
DCE Desktop Client > Device > SNMP Device Communication Settings > Device Scan Settings > Search for device > Check Box on device line item > Edit Device Scan Settings.

STOP!  Navigate to the DCE Desktop Client and click on the Monitoring perspective.  Select the device group that contains the device in lost communication.  Right-click on the device within the device-view pane and select Request Device Scan.  This usually will establish communication, and is only done for testing and troubleshooting purposes.  If the lost communication alarm does not clear, reach out to your local technical support for assistance.  If the lost communication alarm clears, proceed to step 9.

9) Change the settings back to the original within DCE and the NMC, ONE at a time to determine what may be causing the communication issue.  Make any necessary changes to the value that is causing issues, ensuring to update it within DCE and the APC NMC.

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