Protocol Independent Multicast over IPv6

Table 1. PIM over IPv6 product support

Feature	Product	Release introduced
PIM over IPv6	5420 Series	VOSS 8.4
	5520 Series	VOSS 8.2.5
	VSP 4450 Series	VOSS 5.1
	VSP 4900 Series	VOSS 8.1
	VSP 7200 Series	VOSS 5.1
	VSP 7400 Series	VOSS 8.0
	VSP 8200 Series	VOSS 5.1
	VSP 8400 Series	VOSS 5.1
	VSP 8600 Series	Not Supported
	XA1400 Series	Not Supported

Several multicast protocols are used to enable IP multicast.

Hosts use the Internet Group Management Protocol (IGMP) for IPv4 and Multicast Listener Discovery (MLD v1/v2) for IPv6 to report multicast group memberships of directly attached multicast listeners to neighboring multicast routers. MLD is the direct IPv6 replacement for the IGMP protocol used in IPv4.

Routers use Protocol Independent Multicast-Sparse Mode (PIM-SM) and PIM source Specific Mode (SSM) to exchange multicast routing information. The PIM-SM protocol is the multicast routing protocol that uses the underlying unicast routing information base to build unidirectional shared trees to group members rooted at the RP per group, and creates shortest-path trees (SPT) per source. The router forwards multicast packets along these trees. PIM-SSM does not require RP and only supports SPT.

PIM over IPv6 uses the IPv6 unicast routing table for reverse path information about source and RP.