The value of the slice-size i.e. maximum portion of the
mirrored frame that will be transmitted to the mirror
destination. Any frame larger than the slice-size will be
truncated to this value before transmission to the mirror
destination. A value of 0 indicates that mirrored packet
truncation based on slice size is disabled.
When the miror destination is an ISA-AA Group, this must
be set to a value of 0.