181
b.
After a data-delay period has passed, an MDT switchover process starts. All VPN multicast
packets that have entered the public network through that PE device are not encapsulated
with the default-group address. They are encapsulated into public network multicast
packets with the data-group address. Then they are switched from the default-MDT to the
data-MDT.
For more information about MDT switchover, see "
NOTE:
A VPN uniquely corresponds to an MD and an MD provides services for only one VPN, which is
called a one-to-one relationship. Such a relationship exists between VPN, MD, MTI, default-group,
and the data-group range.
PIM neighboring relationships in MD VPN
Figure 60 PIM neighboring relationships in MD VPN
PIM neighboring relationships are established between two or more directly interconnected devices
on the same subnet. As shown in
, the following types of PIM neighboring relationships
exist in MD VPN:
•
PE-P PIM neighboring relationship
—Established between the public network interface on a
PE device and the peer interface on the P device over the link.
•
PE-PE PIM neighboring relationship
—Established between PE devices that are in the same
VPN instance after they receive the PIM hello packets.
•
PE-CE PIM neighboring relationship
—Established between a PE interface that is bound with
the VPN instance and the peer interface on the CE device over the link.
Protocols and standards
RFC 6037,
Cisco Systems' Solution for Multicast in BGP/MPLS IP VPNs
MD
P
PE 3
PE 2
PE 1
CE 3
CE 2
CE 1
PE-PE neighbors
PE-P neighbors
PE-CE neighbors
