Sample STM implementation

STM test suites

The following figure shows a sample STM implementation that illustrates how you can use STM suites to verify service operation and identify network problems.

Figure 89-1: Sample STM implementation

In the sample network, two scheduled STM test suites run constantly to ensure that the transport elements are functioning properly. One test suite monitors the SDPs, and the other test suite monitors the LSPs. An NFM-P administrator can quickly update the test suites, as required, to reflect network topology changes by revising the list of tested entities in the suite and regenerating the tests. An OSS application collects the test result information which is then available for monitoring by NOC staff.

Note: This sample configuration uses an NFM-P schedule to create a scheduled task. See Chapter 5, NFM-P-based schedules for information about NFM-P schedules.

The SDP test suite contains the following generated tests for each SDP:

tunnel ping
MTU ping

The LSP test suite contains the following generated test for each LSP path:

LSP ping (tested entity type is LSP path)

The NOC monitoring staff become aware that tunnel ping operations fail occasionally on one SDP. Packet loss is not yet significant enough to affect SLAs, but threatens to become so, based on the observed trend. NOC staff run a test suite against the LSPs in the affected LSP path.

The test suite contains the following generated test for each LSP in the LSP path:

LSP ping (tested entity type is LSP)

Test results show that the packet loss is related to a specific LSP in the path. Investigation of the LSP traffic pattern indicates that a recently provisioned service is causing the LSP to be oversubscribed. The problem is addressed by a network designer and is corrected through configuration changes.

The following table lists the high-level tasks necessary to configure and use the STM elements in this sample.

Table 89-1: Sample STM implementation configuration sequence

Task	Description
1. Scheduled STM test suite creation	Create STM test policies for transport-layer elements. Create a test policy for the SDPs. Specify Tunnel (SDP) as the Entity Type for the policy, and choose Tunnel Ping and MTU Ping as the test definitions. Create separate tunnel ping definitions for different forwarding classes, as required. Create a test policy for the LSP paths. Specify LSP as the Entity Type for the policy and choose LSP Ping as the test definition. In the test definition, specify LSP Path as the Target Type. Create separate LSP ping definitions for different forwarding classes, as required. Create STM test suites for transport-layer elements. Create a test suite for the SDPs. Specify Tunnel (SDP) as the Entity Type for the suite, choose the SDP test policy, choose the SDPs against which the suite is to run, and use the NFM-P to generate the tests in the suite. Create a schedule for the test suite according to network monitoring requirements, and apply the schedule to the test suite to create a scheduled task. Create a test suite for the LSP paths. Specify LSP as the Entity Type for the suite, choose the LSP test policy, choose the LSP paths against which the suite is to run, and use the NFM-P to generate the tests in the suite. Create a schedule for the test suite according to network monitoring requirements, and apply the schedule to the test suite to create a scheduled task.
2. Data presentation	Customize the tabular display of test results in the NFM-P, or create an OSS application that retrieves test-result data from the NFM-P and presents it as information in graphical format for NOC staff.
3. Creation of non-scheduled STM test suite or individual OAM tests for network troubleshooting	Create an STM test policy for the LSPs for use during network troubleshooting. Create a test policy for the LSPs. Specify LSP as the Entity Type for the policy and choose LSP Ping as the test definition. In the test definition, specify LSP as the Target Type. Create separate LSP ping definitions for different forwarding classes, as required. Create a non-scheduled STM test suite (or individual OAM tests, depending on the number of LSPs involved) for the LSPs in the LSP path. Specify LSP as the Entity Type for the suite, choose the created LSP test policy, choose the LSPs in the LSP path against which the suite is to run, and use the NFM-P to generate the tests for the suite.
4. Network monitoring	Use the NFM-P to display the scheduled test results in tabular format, or use an OSS application to monitor the LSP ping, tunnel ping, and MTU ping diagnostic results in real time. Record inconsistencies and trends, and troubleshoot the network as required. Use the threshold-crossing alarm capabilities to raise alarms when traffic characteristics rise above or fall below specific values.
5. Network troubleshooting	When potential trouble arises, use a non-scheduled STM test suite or individual STM tests to help identify the cause. Create individual tests or edit the existing non-scheduled test suite. Include as tested entities the LSPs that comprise the LSP path and regenerate the tests for the suite, as required. Execute the non-scheduled test suite and monitor the test results. Edit the test definition in the test policy. Change test parameter values as required, regenerate the tests in the suite, and re-execute the suite. Continue to refine the diagnostic test results until the problem manifests itself in the test results.