Patent ID: 7627887

Claim:
A method for providing a multicast of a packet, which is included in a transport stream, in a digital network, the method comprising: receiving at an input port of a multimodulator the transport stream having a plurality of packets included therein; determining from a table whether a given packet of the plurality of packets is a multicast packet or a unicast packet, wherein a multicast packet is designated for transmission from a plurality of modulators included in the multimodulator and a unicast packet is designated for transmission from only one modulator of the plurality of modulators, wherein each modulator of the multimodulator includes an identifier; appending a data unit header to each packet, the data unit header including the modulator identifier identifying one or more of the plurality of modulators from which the packet is to be transmitted; providing each packet to one of a multicast or unicast buffer in accordance with the data unit header, a respective unicast buffer being associated with each of the plurality of modulators of the multimodulator; when a particular modulator is available for transmitting, determining whether to retrieve a packet from an associated multicast or unicast buffer, each packet retrieved from the multicast buffer being copied depending on how many of the plurality of modulators from which the multicast packet is to be transmitted based on the data unit header; stripping the data unit header from each packet prior to transmission from the particular modulator; and modulating and transmitting each packet and copied packet from one of the plurality of modulators; wherein at least some of the appending, providing, determining and stripping is performed by the multimodulator.