The (conceptual) table containing configuration information
for ATM physical interface Service Classes (not
logical port ATM interfaces). An ATM connection (VC or VP)
on an interface is a member of a Service Class. The
Service Class is used in the scheduling discipline that
determines which cell is next transmitted on the
interface. If the rate scheduler has no cell
to be sent in the guaranteed cell-flow on an interface,
a decision is made between all Service Classes with
VCs with cells ready for transmit.