Resolution
The fiber interface has a fixed speed and does not support duplex options, but you can set the interface to negotiate link parameters (the default) or not to negotiate.
For fiber Gigabit Ethernet fiber interfaces, the default is no speed nonegotiate, which sets the speed to 1000 Mbps and enables link negotiation for flow-control parameters and remote fault information. The speed nonegotiate command disables link negotiation. These two commands are the only available options for fiber interfaces.
The default setting is auto, which means, dependent upon what the other end of the link supports, the gigabit port sets the speed and duplex automatically.
Refer to these documents for more information:
