Can 10GE optical interfaces of a switch work upon a unidirectional fiber connection
10GE optical interfaces of a switch cannot work upon a unidirectional fiber connection. A unidirectional fiber connection occurs between two 10GE optical interfaces when one interface is Down because the Rx fiber is removed, while the other interface is still Up because its Rx fiber can receive link_Up signals from the PHY layer.
A switch determines the status of a 10GE optical interface according to the IEEE 802.3ae standard. As defined in this standard, the MAC layer of a 10GE optical can send local_fault and remote_fault signals. A switch can determine the link status based on only the link status of the PHY layer or based on the link status of the PHY layer and the local_fault and remote_fault signals from the MAC layer.
On a Huawei switch, link status of a 10GE optical interface turns Up only when the link status of the PHY layer is Up and both the local_fault and remote_fault signals are 0. When two 10GE optical interfaces are interconnected and the Rx fiber on one interface is removed, this interface goes Down and the MAC layer of the interface generates a local_fault signal. Meanwhile, the local interface sends a fault signal to the remote interface through the Tx fiber. The remote interface receives the link_Up signal from the PHY layer and the remote_fault signal from the MAC layer. Therefore, the link status of the remote interface goes Down.