The board-level protection is used to protect the TBE board. The board-level protection is of two modes: general mode and extended mode. The extended mode requires the SCS board.
Trigger Conditions
The trigger conditions for the board-level protection switching are as follows:
- The board is powered off or offline.
- A cold reset occurs in the board.
- The board is faulty.
- The board generates such alarms: LINK-ERR, RMV, LOS and LOF.
NOTE: In the case of extended board-level protection, LINK-ERRR is not used as a protection switching condition; in the case of non-extended board-level protection, LINK-ERR is used as a protection switching condition.
Working Principle
The board-level adopts the single-ended switching mode and is used to chain and ring networks.
The board-level is classified into the general mode and the extended mode, as shown in Figure 1 and Figure 2.
NOTE: Generally, the board-level protection can be jointly used with the SW SNCP of the L4G board. In this case, the sink of SW SNCP must be configured on the active board of the board-level protection group.
 : Direction of the working signal flow |
 : Direction of the protection signal flow |
 : router |
- In the transmit direction, the client services to be protected are input through two routers (R1 and R2) and are then sent to TBE1 and TBE2. After that, only TBE1 serves as the active board and the signals of TBE1 are cross-connected to the L4G
board for transmission. NOTE:
In the general mode, two routers need be configured and their services must be the same.
- In the receiving direction, when the operating is normal, only the cross-connections of the active board are enabled; that of the standby board is disabled. When the active board at the receiving end is faulty, disable its cross-connections, and enable the cross-connections of the standby board TBE2. The services are switched to TBE2 and are output through router R2.
| : Direction of the working signal flow |
: Direction of the protection signal flow |
| : router |
- In the transmit direction, the client services to be protected are input through router R1. The SCS board dually feeds the signals to the active board TBE1 and the standby board TBE2. After that, only TBE1 serves as the active board and the signals of TBE1 are cross-connected to the L4G board for transmission.
- In the receiving direction, when the operating is normal, only the laser of TBE1 is turned on; that of TBE2 is turned off. The cross-connections of only TBE1 are enabled. When TBE1 is faulty, turn off its laser to disable its cross-connection. As a result, the laser on TBE2 is turned on, and the corresponding protection cross-connections are enabled. The SCS board selectively receives the services of only TBE2.
NOTE: The standby TBE board cannot be configured with any service. When the board-level occurs, all services of the active TBE board are switched to the standby TBE board.