Introduction To Md-Vpn; Basic Concepts In Md-Vpn - HP A6600 Configuration Manual

Supporting information exchange and data conversion between the public network and the VPN
instances

Introduction to MD-VPN

For more information about PIM, BSR, C-BSR, RP, C-RP, SPT, and RPT, see
Comware implements multicast VPN by means of the MD method. This multicast VPN implementation is
referred to as MD-VPN. The most significant advantage of MD-VPN is that it requires only the PE devices
to support multiple instances. Multicast VPN can be implemented without upgrading any CE devices and
P devices, and without changing the original PIM configuration of the CE devices and the P devices. In
other words, the MD-VPN solution is transparent to the CE devices and the P devices.

Basic concepts in MD-VPN

The basic concepts involved in MD-VPN are described in
Table 10 Basic concepts in MD-VPN
Concept
Multicast domain (MD)
Multicast distribution tree (MDT)
Multicast tunnel (MT)
Multicast tunnel interface (MTI)
Share-group
Share-multicast distribution tree
(Share-MDT)
Switch-multicast distribution tree
(Switch-MDT)
Table
Description
An MD is a set of VPN instances running on PE devices that can
send multicast traffic to each other. Each MD uniquely corresponds
to the same set of VPN instances.
An MDT is a multicast distribution tree between all PE devices in the
same VPN. MDT types include share-MDT and switch-MDT.
An MT is a tunnel that interconnects all PEs in an MD for delivering
VPN traffic within the MD.
An MTI is the entrance to or exit of an MT, equivalent to an entrance
to or exit of an MD. PE devices use the MTI to access the MD. An
MTI handles only multicast packets but not unicast packets. An MTI
is automatically created with the configuration of a share-group and
MTI binding for a VPN instance.
In the public network, each MD is assigned an independent
multicast address, called share-group. A share-group is the unique
identifier of an MD in the public network. It helps build a share-MDT
corresponding to the MD in the public network.
A share-MDT is an MDT that uses a share-group as its group
address. In a VPN, the share-MDT is uniquely identified by the
share-group. A share-MDT is automatically created after
configuration and will always exist in the public network, regardless
of the presence of any actual multicast services in the public network
or the VPN.
A switch-MDT is an MDT that uses a switch-group as it group
address. At MDT switchover, PE devices with receivers downstream
join a switch-group, forming a switch-MDT, along which the ingress
PE forwards the encapsulated VPN multicast traffic over the public
network.
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"Configuring
10.
PIM."