69
Figure 28 Multicast data transmission through a tunnel
As shown in
, a tunnel is established between the multicast routers Device A and Device B.
Device A encapsulates the multicast data in unicast IP packets, and forwards them to Device B
across the tunnel through unicast routers. Then, Device B strips off the unicast IP header and
continues to forward the multicast data to the receiver.
To use this tunnel only for multicast traffic, configure the tunnel as the outgoing interface only for
multicast routes.
Configuration task list
Tasks at a glance
(Optional.)
Configuring multicast routing and forwarding
•
(Optional.)
Configuring static multicast routes
•
(Optional.)
Specifying the longest prefix match principle
•
(Optional.)
Configuring multicast load splitting
•
(Optional.)
Configuring a multicast forwarding boundary
•
(Optional.)
Setting the multicast hardware resource mode
NOTE:
The device can route and forward multicast data only through the primary IP addresses of
interfaces, rather than their secondary addresses or unnumbered IP addresses. For more
information about primary and secondary IP addresses, and IP unnumbered, see
Layer 3—IP
Services Configuration Guide
.
Enabling IP multicast routing
Enable IP multicast routing before you configure any Layer 3 multicast functionality on the public
network or VPN instance.
To enable IP multicast routing:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enable IP multicast routing
and enter MRIB view.
multicast routing
[
vpn-instance
vpn-instance-name
]
By default, IP multicast routing is
disabled.
Tunnel
Unicast device Unicast device
Unicast device
Unicast device
Multicast device
Multicast device
Device A
Source
Receiver
Device B