When MVPN auto-discovery is disabled, PIM-SM can be used for I-PMSI, and PIM-SSM or PIM-SM (Draft-Rosen Data MDT) can be used for S-PMSI; When MVPN S-PMSI auto-discovery is enabled, both PIM-SM and PIM SSM can be used for I-PMSI, and PIM-SSM can be used for S-PMSI. In the customer network, both PIM-SM and PIM-SSM are supported.
An MVPN is defined by two sets of sites: sender sites set and receiver sites set, with the following properties:
Hosts within the sender sites set could originate multicast traffic for receivers in the receiver sites set.
Receivers not in the receiver sites set should not be able to receive this traffic.
Hosts within the receiver sites set could receive multicast traffic originated by any host in the sender sites set.
Hosts within the receiver sites set should not be able to receive multicast traffic originated by any host that is not in the sender sites set.
A site could be both in the sender sites set and receiver sites set, which implies that hosts within such a site could both originate and receive multicast traffic. An extreme case is when the sender sites set is the same as the receiver sites set, in which case all sites could originate and receive multicast traffic from each other.
Sites within a specific MVPN may be either within the same, or in different organizations, which implies that an MVPN can be either an intranet or an extranet. A site may be in more than one MVPN, which implies that MVPNs may overlap. Not all sites of a specific MVPN have to be connected to the same service provider, which implies that an MVPN can span multiple service providers.
Another way to look at MVPN is to say that an MVPN is defined by a set of administrative policies. Such policies determine both sender sites set and receiver site set. Such policies are established by MVPN customers, but implemented by MVPN service providers using the existing BGP/MPLS VPN mechanisms, such as route targets, with extensions, as necessary.