Record the maximum frame transmission size for the service.

Choose Manage→Service Tunnels from the NFM-P main menu. The Manage Service Tunnels form appears.

Filter to list only the source and destination routers of the service tunnel and click Search. The list of service tunnels appears.

Double-click on a service tunnel from the list. The Tunnel (Edit) form appears.

Click on the Tests tab.

Click on the MTU Ping tab and click Create. The MTU Ping (Create) form appears with the General tab selected. The form displays information about the service tunnel being tested and the originating tunnel ID.

Note: You must use the MTU Ping diagnostic to test the service in both directions for the connection.

Configure the required parameters for the diagnostic session. Click on the Test Parameters tab and enter the MTU value recorded in Step 1 for the MTU End Size (octets) parameter.

Run the diagnostic. The MTU Ping increments the datagram size until it fails to pass through the SDP (service tunnel) data path, in this case, an MTU Ping from site ID 10.1.200.52/32 to site ID 10.1.200.53/32 using the network in Figure 6-1, Sample network.

Click on the Results tab to view the list of trace responses. Double-click on a row in the list to view its details. The number of responses is determined by the incremental increase in datagram size.

Review the diagnostic results and assess whether the configuration meets the network requirements. Click on the Packets tab.

1. If the Status column displays Response Received for all circuits, the service tunnel supports the configured frame transmission size for the circuit. Go to Stage 7 a 2 in Workflow to troubleshoot a service or connectivity problem.

2. If the Status column displays Request Timed Out for any of the circuits, the transmission failed at that frame size. If the frame size for the failure point is below the MTU value configured for the service, the packets are truncating along the service route. Investigate the cause of the truncated packets.

If the service problem persists, another type of service problem may be present. Perform the steps of the troubleshooting workflow in this chapter.

If the troubleshooting workflow does not identify the problem with your service, contact your technical support representative; see Chapter 1, NSP troubleshooting overview.

End of steps