Verifying SW SNCP Switching

This section takes a ring network formed by two stations as an example to describe the test procedure of the SW SNCP protection switching.

Prerequisites

The SW 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, signal analyzer, optical fiber, flange, optical attenuator

Set-up Diagram

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

Figure 1 Testing the SW SNCP

: Fixed optical attenuator

1,2.3,4: OTU Board

Procedure

Connecting Test instruments
1. In station A, respectively connect the output and input optical interfaces of the signal analyzer to the input optical interface RX and output optical interface TX on the client side of the OTU with the fixed optical attenuator in between.
2. In station B, connect the input optical interface RX and the output optical interface TX on the client side of the OTU 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 the Station A
1. Log in to the U2000 Web LCT. Double-click the ONE icon of the Station A in the Main Topology, and the status figure of the ONE is displayed.
2. Right-click the NE icon and select NE Explorer to display the NE Explorer dialog box.
3. Click the NE in the NE Explorer, and choose Configuration > WDM Service Management from the Function Tree. 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 in the right-hand pane. The Current Status of SW SNCP should be Normal State.
5. Check the channel status of the SW SNCP. The channel status of Working cross-connection is normal, the channel status of Protection cross-connection is normal.
Testing the Protection Switching of the Equipment
1. The switching test of the SW SNCP can be performed in two ways.
  - Method 1: fiber removing. Remove the fiber of the IN optical interface of the 2nd working OTU 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.
  NOTICE:
  In Method 1, you must disconnect the fiber that inputs signals to the 2nd working OTU board in station A. Otherwise, protection switching may be performed twice or no protection switching is performed. In this way, the detected switching time is more scientific.
2. Query the channel states of the SW SNCP protection in station A.
  - Choose Configuration > WDM Service Management from the Function Tree. 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 Channel. 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.