Figure 5: Packet Flow With Hardware Multicast Packet Replication - Juniper JUNOSE 11.1.X MULTICAST ROUTING Configuration Manual

one copy of the packet is transmitted from the line module to the I/O module or IOA.
Replication for each of the ports is performed on the I/O module or IOA.
Configuring hardware multicast packet replication for high-density Ethernet is useful
when you want to provide the same multicast stream out of some or all of the ports,
such as for IP television (IPTV). Configuring hardware multicast packet replication
enables you to:
You can use the additional bandwidth to increase the bandwidth of multicast traffic
out of each of the Gigabit Ethernet ports.
Figure 5 on page 19 displays the flow of a multicast packet using the hardware
multicast packet feature.

Figure 5: Packet Flow with Hardware Multicast Packet Replication

Reduce the number of packets sent from the FC to the module.
Reduce the CPU consumed by the FC processing each elaboration of the packet.
Chapter 1: Configuring IPv4 Multicast
Configuring Hardware Multicast Packet Replication
19