Alcatel-Lucent 7750 SR Manual page 1084

VPRN Features
The demarcation of these domains is in the PE's (routers 5 through 10). The PE router participates
in both the customer multicast domain and the provider's multicast domain. The customer's CEs
are limited to a multicast adjacency with the multicast instance on the PE specifically created to
support that specific customer's IP-VPN. This way, customers are isolated from the provider's
core multicast domain and other customer multicast domains while the provider's core routers
only participate in the provider's multicast domain and are isolated from all customers' multicast
domains.
The PE for a given customer's multicast domain becomes adjacent to the CE routers attached to
that PE and to all other PE's that participate in the IP-VPN (or customer) multicast domain. This is
achieved by the PE who encapsulates the customer multicast control data and multicast streams
inside the provider's multicast packets. These encapsulated packets are forwarded only to the PE
nodes that are attached to the same customer's edge routers as the originating stream and are part
of the same customer VPRN. This prunes the distribution of the multicast control and data traffic
to the PEs that participate in the customer's multicast domain. The Rosen draft refers to this as the
default multicast domain for this multicast domain; the multicast domain is associated with a
unique multicast group address within the provider's network.
Page 1084 7750 SR OS Services Guide