The principles of DLAG feature of Huawei DWDM Equipment

When the main board like Huawei TN52SCC on Huawei OSN8800 or OSN6800  detects a failed port, the cross-connect board switches the services carried by the failed port from the main board to the slave board to protect the services.

Figure 1 shows the processing flow of a DLAG.

Figure 1 Processing flow of a DLAG 

In the transmit direction, the processing flow of the DLAG is described as follows:

• The cross-connect board of NE1 transmits the services to the main board and slave board of the DLAG. Then, the main board and slave board of the DLAG transmit the services to the equipment at the opposite end.
• When a link down failure, a board offline event, or a hardware failure occurs on the main board, the equipment at the opposite end receives the signals sent by the slave board.

In the receive direction, the processing flow of the DLAG is described as follows:

• The main board and slave board of NE1 transmit the main services and slave services sent from the opposite end respectively to the cross-connect board of NE1. The cross-connect board of NE1 selects services between the main services and slave services.
• When the main board works normally, the cross-connect board selects the services sent by the main board.
• When the main board detects a link down failure, a board offline event, or a hardware failure, the cross-connect board selects the services sent by the slave board to protect the services.