Verifying Optical Line Protection Switching

This section takes a ring network formed by two OTM stations to describe the test procedure of the optical line protection switching.

Prerequisites

The optical line 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 optical line protection switching is shown in Figure 1.

Figure 1 Testing the optical line protection

: Fixed optical attenuator

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.
Querying the Normal Channel Status of the Station A
The related parameters of the OLP are configured on the U2000 Web LCT. For configuration procedure, refer to the Creating Optical Line Protection in the Feature Description.
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 where the OLP board is located and select NE Explorer to display the NE Explorer dialog box.
3. Select the NE from the Navigator Tree and choose Configuration > Port Protection from the Function Tree.
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.
5. Check the channel status of the optical line protection. The Working Channel is 1(RI1/TO1) and the Protection Channel is 2(RI2/TO2). The Working Channel Status and the Protection Channel Status is Idle.
Testing the Protection Switching of the Equipment
1. The switching test of the optical line protection can be performed in two ways.
  - Method 1: fiber removing. Remove the fiber of the RI1 interface of the OLP board in Station A to perform the switching.
  - Method 2: forced switching. On the U2000 Web LCT, log in to station A. Right-click the desired protection group , and select Force to Protection Channel to perform the switching. Click OK in the dialog box displayed.
2. Query the channel states of the optical line protection after the switching in station A.
  - Choose Configuration > Port Protection from the Function Tree. Click Query, a prompt appears to indicate that the operation was successful. Click Close.
  - In the fiber removing mode, Working Channel is 1(RI1/TO1), and Protection Channel is 2(RI2/TO2). Working Channel Status is SF Switched; Protection Channel Status is Idle. Switching Status is Switching.
  - In the forced switching mode, Working Channel is 1(RI1/TO1), and Protection Channel is 2(RI2/TO2). Working Channel Status and the Protection Channel Status is Idle. Switching Status is Switching.
3. In the NE panel of the Station A, right-click the OLP board and select Browse Current Alarms.
  - If the protection group is automatically switched, the OLP board reports AUTOSW.
  - If the protection group is forced switched, the OLP board reports FRCDSW.
4. Test the services and switching time by using a signal analyzer. The services should be available, 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: Right-click the desired protection group in the Protection Group, and select Clear. Click OK in the dialog box displayed.
  NOTE:
  If the Restore Mode field is set to Non-Revertive, right-click the desired protection group and then choose Manual to Working Channel from the shortcut menu. After that, right-click the same protection group again and then choose Clear from the shortcut menu. Click OK in the dialog box displayed.
6. After the time set in WTR Time(mm:ss) field, Click Query, a prompt appears to indicate that the operation was successful. Click Close. And Switching Status of the protection group should be Idle.