This attribute counts the frames lost in the direction from interface,
the loss of which is detected based on the sequence number
mechanism. The reason for a loss may be the congestion-related
loss in the external frame relay network, or errors/congestion
developing in the FrMux service. When FrMux statistics do not
show errors/congestion developing internally in FrMux, then the
losses visible through this statistic should be attributed to the
external frame relay network. When the maximum count is reached
the count wraps to zero.