How can I troubleshoot Twamp-light test issues?

Troubleshooting suggestions

The following guidelines apply to Twamp-light tests, but may also be useful for other test types. Contact support if you need further assistance.

• The test doesn’t start.

  Usually, errors on test execution occur when there is a difference in state between the NSP and the NE or if test attributes are outside the accepted range of the NE. In this case, follow guidance from the error or warning message returned when the test is started. Executing the test in sync-mode “sync-execute” ensures that the most complete error and warning messages are shown.

• The test starts and results are received, but the packet counts and delay values are all zero.

  • Confirm that the destination address is reachable from the NE executing the test.   

  • Confirm that the Twamp-light reflector is enabled, that the test dst-udp-port parameter matches the reflector listening port, and that the Twamp-light reflector has a matching prefix for the test src IP address parameter.

• The test starts but no results are observed.

  • Check the execution status to confirm that the test is executing.

  • Confirm the test type and the expected result classes. Verify from the results class (streaming or accounting) the expected delay until the first result should arrive. Confirm that the correct class of result is selected, and click Refresh Results to trigger result retrieval from results stored to the database.

  • Confirm that the configuration is correct and complete: the deployment state is “deployed”, the streaming template is defined (for intended streaming delay results), the bulk result is true (for intended accounting results), and properties (IP addresses, UDP ports, measurement interval) are correct.

  • If streaming test results are intended, validate the configuration and status of the streaming delay template (especially the admin state and sample window period).

  • Validate telemetry subscriptions for the test classes: telemetry subscriptions are created automatically for tests created in the NSP. The subscription name format is TestSuiteEx_OAM-PM-test_type-statistic-type; for example, the subscription for Twamp-light delay streaming statistics would be named TestSuiteEx_OAM-PM-TWAMP-streaming.

  • Validate the Twamp-light reflector configuration:

    Does the target node have a deployed, enabled reflector?

    Does the UDP port match those of configured tests?

    Is the reflector on the correct routing instance (router- or service-based)? Twamp-light reflector prefixes can be viewed from the RESTCONF API.

  • Validate the bin group information for accounting type results: confirm that the bin group configured in the test is configured on the node and that admin state is enabled. Details of bin groups may be configured or retrieved using RESTCONF API or discovered from node configuration.