In the case of the OptiX OSN 6800, the XCS should be configured to achieve centralized grooming of electrical-layer cross-connections. As the XCS boards are of 1+1 hot backup, the OTU board (or a tributary/line board) selectively receives service signals from the active and standby XCS boards. When a board becomes faulty, the OTU board (or the tributary/line board) determines whether the signal failure is from the active XCS board or the standby XCS board according to the BUS_ERR alarm, and then automatically switches to the normal bus.
Take the following scenario for example:
An ODU1 service is configured from the TDG to the NS2. Inside the equipment, the ODU1 service traverses the active and standby XCS boards. The TDG selects the service signals from the active or standby XCS by detecting the signal quality.
1. Meanings of the parameters in the BUS_ERR alarm are defined as follows in related product manuals:
The first parameter indicates that the bus is faulty, and this parameter is always 0x01.
The second and the third parameters indicate the number of the bus sending the alarm, and the two parameters occupy two bytes. The value range of the second and the third parameters: 0x01 0x2c � 0x01 0x30, 0x01 0x40 � 0x01 0x44.
0x01 0x2c � 0x01 0x30 indicates that the active XCS board is faulty; 0x01 0x40 � 0x01 0x44 indicates that the standby XCS board is faulty.
2. For example, the TDG board reports: 129028 102 BUS_ERR CR start
2007-12-28 16:40:53 None 0x01 0x01 0x2c 0xff 0xff
According to the parameters, the TDG board knows that No.300 bus of the active XCS board is faulty, and automatically receives signals from the standby XCS board.
For the OTU board:
Channels 300-307 are active channels, and the OTU board selectively receives signals from the active XCS board; channels 320-327 are active channels, and the OTU board selectively receives signals from the standby XCS board.
300 = 0x12c= 0x01 0x2c
320 = 0x140= 0x01 0x40