In an MVPN network, a provider pdge (PE) router has a multicast routing table and a Protocol Independent Multicast (PIM) instance
associated with every VPN routing and forwarding (VRF) table that is used to define the VPN membership of customer sites attached
to the router. There is one global multicast routing table and a table per multicast VRF (MVRF) used to route multicast packets
received from a customer edge (CE) router. A set of MVRFs form a multicast domain (MD) when they are connected to potential
sources and receivers of multicast traffic. A distinct group address, also known as the Multicast Distribution Tree (MDT)
group address, obtained from an administrative pool, is assigned to each multicast domain. MDT groups are used by PE routers
to encapsulate and transport multicast traffic within an MD through multicast tunnel interfaces (MTIs).
Initially all multicast data is forwarded using preconfigured MDT default groups. When certain multicast streams exceed a
configured bandwidth threshold on the PE router, the multicast data is moved to an MDT data group that is dynamically chosen
from an available pool of multicast addresses.
Using the MVPN MIB, network administrators can access MVRF information from PE routers for VPN traffic across multiple CE
sites in real time. SNMP operations can be performed to monitor the MVRFs on the PE routers using get and set commands entered on the network management system (NMS) workstation for which SNMP has been implemented. The NMS workstations
is also known as the SNMP manager.