This read-only enumeration (port-based(1), card-based(2)) indicates whether the port's SVC logical channel number pool is shared on a per-port or per-card basis; it is not supported on FRSM12. An administrator reads this to understand whether SVC LCN allocation for this port is isolated to the port itself or shared more broadly across the whole card. For example, a card-based(2) setting means the LCN range reported by portSvcLcnLow/High for this port is actually shared with other ports on the same card, unlike a port-based(1) setting where the range is exclusive to this port.