When a TBE board is configured only with a unidirectional cross-connection, the unidirectional service is not available. When the TBE board is configured with bidirectional cross-connections, the bidirectional service is normal; When a unidirectional cross-connection is deleted, however, the service becomes unavailable.
Configure the TBE board with bidirectional cross-connections.
When a TBE board is configured with a unidirectional cross-connection, the PHY chip at the receive end becomes linkdown and cannot extract clock signals from the received data. The PHY chip needs to use the clock signal extracted from the received data when sending data. As a result, the PHY chip fails to send data and the unidirectional service is unavailable.