An apparatus in a digital network receives digital packets, such as MPEG
packets, included in at least one input transport stream and outputs a
plurality of modulated output transport streams. The apparatus determines
whether the input transport streams include packets that are for
multicasting from a plurality of the modulators included within the
apparatus. The apparatus also determines whether the input transport
streams include unicast packets that are transmitted from only one of the
output modulators of the apparatus. The apparatus identifies the unicast
and multicast packets of the input transport streams and associates a
modulator for each unicast packet. The associated modulator of a unicast
packet is the particular modulator from which the packet is modulated and
transmitted. The apparatus also associates a plurality of modulators with
each multicast packet, wherein the associated plurality of modulators are
the modulators from which the multicast packet is transmitted.