Description: In case of an optical interface where the transmitted and received signals travel on two different strands of fiber, it is possible that each fiber is patched to a different interface. For example, the transmit and receive fibers of this interface may have unidirectional connections to different optical amplifiers.

This object indicates whether this entry describes a patch in the receive direction, the transmit direction or both directions. If both the transmit and receive fibers of this interface are patched to the same interface, then this object is set to 'both'. Individual entries for 'transmit' and 'receive' should not be created in this case.