Verifying Tributary Protection Switching

This topic considers a ring network as an example to describe the test procedure of the tributary SNCP protection switching. The ring network consists of two stations in which the tributary board and the line board are jointly used

Prerequisites

The tributary SNCP protection must be configured.

The fiber connections between station A and station B must be complete.

The equipment must be running normally.

Tools, Equipment and Materials

U2000 Web LCT, optical fiber, flange, signal analyzer, optical attenuator

Test Connection Diagram

The diagram of testing tributary SNCP protection switching is shown in Figure 1.

Figure 1 Testing tributary SNCP protection switching

: Fixed Optical Attenuator

Procedure

Connecting Test Instruments
1. At station A, connect the output and input optical interfaces of the signal analyzer to the RX and TX interfaces on the client side of the OLP protection board respectively with the fixed optical attenuator in between.
2. At station B, connect the input optical interface RX and the output optical interface TX on the client side of the OLP protection board with the fixed optical attenuator in between to realize the loopback on the client side, as shown in Figure 1.
3. Test the channel by using a signal analyzer to ensure that no bit error is generated.
Querying the Normal Channel Status of Station A
1. Log in to the U2000 Web LCT. Double-click the NE A in the Main Topology, and the status figure of the NE A is displayed.
2. Right-click a NE icon and select NE Explorer to display the NE Explorer dialog box.
3. Select the NE from the Navigator Tree in the left-hand pane, choose Configuration > WDM Service Management from the Function Tree, and click SNCP Service Control.
4. Click Query, a prompt appears to indicate that the operation was successful. Click Close. And all protection groups are listed in the protection group list. Current Status of the tributary SNCP protection is Normal State.
5. Query the channel states of the tributary SNCP protection. Channel status of the working cross-connection is normal, and channel status of the protection cross-connection is normal.
Testing the Protection Switching of the Equipment
1. The switching test of the tributary SNCP protection can be performed in two ways:
  - Method 1: fiber removing. Remove the fiber in the TXn optical interface on working line board TQM1 in station A to perform the switching, as shown in Figure 1.
  - Method 2: forced switching. In the SNCP Service Control interface of station A, select the working cross-connection, and click Function. In the displayed menu, select Force to Protection to perform the switching. Click OK in the dialog box displayed.
2. Check the channel status of tributary SNCP protection of station A
  - Choose Configuration > WDM Service Management from the Function Tree, and click SNCP Service Control. Click Query, a prompt appears to indicate that the operation was successful. Click Close.
  - In the fiber removing mode, channel status of the working cross-connection is SF, and channel status of the protection cross-connection is normal. Current Status of the protection group is SF Switching.
  - In the forced switching mode, channel status of the working cross-connection is normal, and channel status of the protection cross-connection is also normal. Current Status of the protection group is Forced (from Working to Protection) Switching State.
3. In the NE panel of the Station A, right-click the board and select Browse Current Alarms.
  - If the protection group is automatically switched, the board reports AUTOSW.
  - If the protection group is forced switched, the board reports FRCDSW.
  For details about the board that reports the alarm, refer to Alarms and Performance Events Reference.
4. Test the services and switching time by using a signal analyzer. The services should be available , no bit error is generated, and the switching time should be less than 50 ms.
5. To restore the test environment of the two switching modes in Step 1, the following two modes can be respectively used:
  - Fiber removing mode: Reconnect the fiber.
  - Forced switching mode: Select the working cross-connection, and click Function. In the displayed menu, select Clear. Click OK in the dialog box displayed.
  NOTE:
  If the Restore Mode field is set to Non-Revertive, select the desired working cross-connection, and click Function. In the displayed menu, choose Manual to Working. After that, right-click the same working cross-connection again, click Function. In the displayed menu, choose Clear. Click OK in the dialog box displayed.
6. Click Query, a prompt appears to indicate that the operation was successful. Click Close. And Current Status of the protection group should be Normal State.