A system and method for routing multicast packets. A multicast packet is received at an inbound interface on a switch/router. S,G data are obtained from the packet and used to search an OIL table. If the S,G data are found in the OIL table, the packet is forwarded on an outbound interface associated with the S,G data. If the S,G data are not found in the OIL table, the multicast routing table is consulted to obtain a longest match for the packet, and the packet is forwarded on the interface(s) which correspond to the longest match route. The multicast routing table may include a single entry, such that all packets that do not match an entry in the OIL are forwarded on the same outbound interface. The multicast routing table may include multiple entries with different covered ranges of (S,G).