Switching time of protection configured using DCP boards


The DCP board can be used to configure inter-subrack 1+1 optical channel protection and extended intra-board wavelength protection. The protection switching time is less than 50 ms and meets the ITU-T standards.

Other related questions:
Principles for inter-board OLP or DCP protection
The OLP and DCP boards have the same functions and implementation modes. A DCP board has two optical ports, which can emit four light signals. Therefore, one DCP board functions as two OLP boards. The following uses OLP as an example. 1. OLP applies to line protection. [Application scope]: An OLP board is a 1+1 optical line protection board and implements 1+1 protection for optical line signals. [Working principle]: In a DWDM system, the transmit-end FIU board transmits light to the OLP board so that it is split at a ratio of 1:1. The two channels of split light are transmitted to the working fiber (channel) and protection fiber (channel) respectively. At the receive end, the OLP board detects and compares the optical power of the light on the working and protection channels. Based on the protection switching conditions, the OLP board determines whether to enable the optical switch to protect fiber routes and the services carried on the fiber routes. 2. OLP applies to client protection. [Application scope]: OLP is used for client protection. [Working principle]: (1) An OTU board detects an abnormality and reports a message to the system control board. (2) The message is sent from the OTU board to the system control board. (3) The system control board responds to the interrupt request (Fast_Int) of the OTU board and issues a command to request to shut down the client-side laser of the OTU board. (4) The command is sent from the system control board to the OTU board. (5) The OTU board receives the command and shuts down the client-side laser. (6) The OLP board detects and compares the optical power of the light on the working and protection channels. After detecting an optical power change, the OLP board switches the route.

Protection implemented by TOM and DCP boards
Intra-board 1+1 protection can be implemented when the TOM board works with the DCP board.

Method used to specify the working and protection trails of an intra-board 1+1 protection group on DCP boards
Select ports 1(RI11/TO11) and 2(RI12/TO12) of the DCP boards as the working and protection trails respectively. Alternatively, select ports 3(RI21/TO21) and 4(RI22/TO22) of the DCP boards as the working and protection trails respectively.

Optical power difference between the working and protection trails on the DCP board to trigger protection switching
When the optical power difference between the working and protection trails exceeds a specified threshold, a POWER_DIFF_OVER alarm is reported and this alarm will trigger OLP protection switching. This threshold is configurable, and the default value is 5 dB.

Method used to handle the PS alarm reported by an unused protection group of a DCP board
Question: The first protection group on a DCP board of a WDM network is used. The second protection group is not used, but the PS switching alarm is reported. What are the methods of monitoring the impact and handling the issue? Once the alarm is masked, the PS alarm of the first protection group is masked. Analysis: 1. BWS 1600G NEs support DCP boards of various versions. The PS alarms of the DCP boards are reported when the optical switches are in the standby state. Because the alarm distinguishes the protection groups according to alarm parameters, PS alarms of the entire board will be not monitored if the alarms are masked. Therefore, the alarms cannot be handled by masking them. 2. Based on the DCP board alarm mechanism, you can clear the PS alarm by setting the second optical switch to active. 3. Because there is no command for directly changing the optical switch status, use the second protection group that is logically configured and lock out the optical switch to the active state. Then the issue is rectified. Answer: 1. Configure two logical OTU boards on the NMS, and configure the second protection group to a wavelength protection group. 2. Issue a lockout command to this new protection group on the NMS. The alarm is cleared. 3. Delete the new logical protection group and OTU board.

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