Use this procedure to change the Slot Protection State for the Main slots equipped with VLNC50/52/55 circuit packs.

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Slot Protection State parameter

The Slot Protection State parameter specifies whether the VLNC50/52/55 circuit packs in the Main slots are unprotected (default) or equipment protected. The Slot Protection State parameter does not apply to VLNC40/42/42B, VLNC60/61/62, and VLNC64 circuit packs. For example, inserting a VLNC40 circuit pack beside a VLNC50/52/55 circuit pack when the Slot Protection State is provisioned Protected has no effect (no alarms).

When the Slot Protection State is Unprotected, a VLNC50/52/55 circuit pack is supported in the Main 1 slot only. If a VLNC50/52/55 circuit pack is inserted in the Main 2 slot, the system reports an unexpected CP type alarm. The optical lines support unprotected 0x1 applications and protected UPSR/SNCP applications. Protection is between the two optical lines on the VLNC50/52/55 circuit pack in Main slot 1 (that is, main-1-1 and main-1-2). For unprotected 0x1 applications the values of the port Signal Type parameters are independent. For protected UPSR/SNCP applications the values of the port Application and Signal Type parameters for both optical lines on the circuit pack are the same value.

When the Slot Protection State is Protected, VLNC50/52/55 circuit packs are supported in the Main 1 and Main 2 slots. The optical lines support unprotected 0x1 applications and protected 1+1/UPSR/SNCP applications. Protection is between the equivalent optical lines on the circuit packs (for example, main-1-1 and main-2-1). For unprotected 0x1 applications the values of the port Signal Type parameters are independent. For protected 1+1/UPSR/SNCP applications the values of the port Application and Signal Type parameters for both optical lines are the same value. If the Main 2 slot is unequipped, the VLNC50/52/55 circuit pack in Main slot 1 operates unprotected.

Slot Protection State provisioning guidelines

The following guidelines apply to provisioning the Slot Protection State parameter:

1. The Slot Protection State parameter cannot be changed if cross-connections exist on the VLNC50/52/55 circuit pack or the companion circuit pack.

2. The Slot Protection State parameter cannot be changed if cross-connect loopbacks exist on the VLNC50/52/55 circuit pack or the companion circuit pack.

3. The Slot Protection State parameter cannot be changed if both Main slots are unequipped.

4. The Slot Protection State parameter cannot be changed from unprotected to protected if the VLNC50/52/55 circuit pack LAN interface parameter is provisioned BP. The VLNC50/52/55 circuit pack LAN Interface parameter must be provisioned PTM.

5. The Slot Protection State parameter cannot be changed from unprotected to protected if synchronization reference switching is inhibited and the system is selecting an optical line that would no longer be valid after the provisioning change.

6. The VLIU10 interface unit is required for VLNC52/55 equipment protection. The VLIU1 or VLNC10 interface unit may be used for VLNC50 equipment protection.

7. The Main 1 slot must be equipped with a VLNC50/52/55 circuit pack to change the Slot Protection State parameter from Protected to Unprotected.

8. The Main 2 slot must be unequipped to change the Slot Protection State parameter from Protected to Unprotected.

9. Removing a circuit pack from a slot and transitioning the slot to be unequipped does not change the Slot Protection State.

Prior to performing this procedure:

1. Refer to Before you begin and Required equipment in this chapter.

2. Obtain the work instructions for this procedure.

3. Verify the work instruction specify the parameters and values to be provisioned.