3com S7906E 설치 설명서

 

1-4 

For details about the concepts of Protocol Independent Multicast (PIM), bootstrap router (BSR), 

candidate-BSR (C-BSR), rendezvous point (RP), candidate RP (C-RP), shortest path tree (SPT) and 

rendezvous point tree (RPT), refer to PIM Configuration in the IP Multicast Volume.  

 

Comware implements multicast VPN by means of the multicast domain (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.  

The basic concepts involved in MD-VPN are described in 

.  

Table 1-1 Basic concepts in MD-VPN 

Multicast domain (MD) 

An MD is a set of VPN instances running on PE routers that 
can send multicast traffic to each other. Each MD uniquely 
corresponds to the same set of VPN instances. 

Multicast distribution tree (MDT) 

An MDT is a multicast distribution tree between all PE devices 
in the same VPN, such as share-MDT.  

Multicast tunnel (MT) 

An MT is a tunnel that interconnects all PEs in an MD for 
delivering private network traffic within the MD.  

Multicast tunnel interface (MTI) 

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.  

Share-group 

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 is used to 
build a share-MDT corresponding to the MD in the public 
network.  

Share-multicast distribution tree 
(Share-MDT) 

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. 

 

Main points in the implementation of MD-VPN are as follows:  

1)  The public network of the service provider supports multicast. The PE devices need to support the 

public instance and multiple VPN instances, each instance running PIM independently. Private 

network multicast traffic between the PE devices and the CE devices is transmitted on a