Assign/remove test signal generator/detector to internal test access session

Procedure 14-33: Assign/remove test signal generator/detector to internal test access session

Overview

Important!

The network element must be equipped with Very Large Fabric (VLF) circuit packs in the Main slots to support internal test access sessions.

Use this procedure to perform the following changes to an existing internal test access session:

Assign/remove a pseudo-random bit sequence (PRBS) test signal generator
Assign/remove a pseudo-random bit sequence (PRBS) test signal detector.

To view test measurements for an existing internal test access session, refer to Procedure 14-34: View test measurements for internal test access session.

To restart monitoring and initialize the counting bins to 0 for an existing internal test access session, refer to Procedure 14-35: Initialize test measurements for internal test access session.

Privilege level

You must log in as either a Privileged, General, or Maintenance user to complete this procedure.

Test Signal Generator parameter

A pseudo-random bit sequence (PRBS) test signal generator is assigned or removed from an internal test access session using the Test Signal Generator parameter.

When the Test Signal Generator parameter is provisioned to PRS, a test signal generator is assigned and a pseudo-random bit sequence is transmitted. While a test signal generator may be assigned to a test access session in the MONE test access mode, the transmitted test signal cannot be monitored until the test access session is changed to the SPLT(A or E) test access mode. A request to assign a test signal generator is denied if the requested test signal generator (or generators) is not available. A test signal generator is assigned until it is removed or the test access session is deleted.

When the Test Signal Generator parameter is provisioned to <NULL>, any test signal generators that were assigned are removed and AIS is inserted.

Test Signal Detector parameter

A pseudo-random bit sequence (PRBS) test signal detector is assigned or removed from an internal test access session using the Test Signal Detector parameter.

When the Test Signal Detector parameter is provisioned to PRS, a test signal detector is assigned and the pseudo-random bit sequence is monitored. If the test signal is not detected within 2 seconds, the command is denied, and the detectors are freed. Once the test signal is detected, counting bins are initialized, and counting of errors on the test signal begins. The network element maintains a current 15-minute bin, up to 32 previous 15-minute bins, a current day bin, a previous day bin, and a total bin. A test signal detector is assigned until it is removed or the test access session is deleted.

When the Test Signal Detector parameter is provisioned to <NULL>, any test signal detectors that were assigned are removed and no signal is monitored. Any counting bins associated with the session remain available until the test access session is deleted or monitoring is restarted.

Recommended external test head settings

The internal test head may not be compatible with some external test sets. The following settings are recommended for external test sets:

For STS-1:

- Mode = SDH

- Payload = AU-3, Bulkfill

- Pattern=2²³-1 PRBS, NORMAL
For STS-3c:

Same as STS-1, except for 3 STS-1 signals. This may require the test set to be set to background = foreground for the entire signal.

Restrictions

The following restrictions apply:

A new internal test access session can be created only in the MONE test access mode initially.
The network element must be equipped with Very Large Fabric (VLF) circuit packs in the Main slots to support internal test access sessions.
The VLF circuit packs in the Main slots have 12 STS-1 signals routed to test signal generators and 12 STS-1 signals routed to test signal detectors. For STS-3 test access sessions, 3 STS-1 generators/detectors on the STS-3 boundary (1, 4, 7, 10) must be available.

NOTICE

Service-disruption hazard

Service interruptions can occur on tributaries if they are accidentally tested. Service interruptions may also occur on unintended tributaries if unsupported test access configurations are attempted.

Recheck the address (AID) of the tributary(ies) being tested. Do not attempt to establish unsupported test access sessions.

Before you begin

Prior to performing this procedure:

Refer to Before you begin and Required equipment in this chapter.
Refer to Electrostatic discharge in Chapter 1, Safety.
Obtain the work instructions for this procedure.
Verify that the work instructions identify the test access session number and the test signal changes to be provisioned.

Steps

Complete the following steps to assign/remove a test signal generator/detector to an existing internal test access session.


1	From the System View menu select Fault → Analysis → Test Access. Result: The Test Access Wizard appears.
2	Click Modify an existing test access session's mode and Next.
3	Follow the directions in the remaining Test Access Wizard screens to assign/remove a test signal generator/detector to the internal test access session. For more information about the Test Signal Generator and Test Signal Detector parameter changes, refer to Test Signal Generator parameter and Test Signal Detector parameter.
4	Important! A test signal generator/detector is assigned until it is removed or the internal test access session is deleted. Verify the Test Signal Generator and Test Signal Detector parameters, then click Finish at the end of the Test Access Wizard screens. Result: A dialog box appears asking you to confirm executing this command. Click Yes and the Test Access Wizard appears.
5	Click View existing test access sessions and Next. Result: A list of existing test access sessions appears.
6	Verify that the test signal generator/detector changes were made to the required internal test access session and click Close. End of steps