NE80 connects with the device of C company through POS interface. When the closest port is loopback, the physical and protocol state are down, but interface light on the board flashes. Change local clock as master and it is normal.
Topology: NE80 155M POS interface---------optical transmission--------C company 155M POS
1. Change the clock as master, and then the loopback of nearest port succeeds.
2. During the connection with C company, the protocol is down. CRC check character of opposite POS interface is 16-bit and that of NE80 is 32-bit. Change opposite one as 32-bit, the protocol is up. The link is normal.
1. For the loopback of common ppp protocol link, set the clock as master.
2. Connect with POS of C company, CRC check character of C company is 16-bit, ours is 32-bit and it cannot be configured.
Tx Clock Source: Internal, FCS: 32-bit CRC, SPE Scrambling: Enabled
During the realization of NE80, CRC check character of POS interface is 32-bit and it cannot be configured.