H3C Technologies H3C SecPath F1000-E - Manual (Page 154)

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IPv6 Multicast Routing and Forwarding
Configuration
This chapter includes these sections:
• IPv6 Multicast Routing and Forwarding Overview
• Configuration Task List
• Displaying and Maintaining IPv6 Multicast Routing and Forwarding
• Troubleshooting IPv6 Multicast Policy Configuration
NOTE:
The term router in this document refers to network routing devices running a routing protocol.
IPv6 Multicast Routing and Forwarding Overview
Introduction to IPv6 Multicast Routing and Forwarding
In IPv6 multicast implementations, multicast routing and forwarding are implemented by three types of
tables:
Each IPv6 multicast routing protocol has its own multicast routing table, such as IPv6 PIM routing table.
The multicast routing information of different IPv6 multicast routing protocols forms a general IPv6
multicast routing table.
The IPv6 multicast forwarding table is directly used to control the forwarding of IPv6 multicast packets.
This is the table that guides IPv6 multicast forwarding.
An IPv6 multicast forwarding table consists of a set of (S, G) entries, each indicating the routing
information for delivering multicast data from a multicast source to a multicast group. If a router supports
multiple IPv6 multicast protocols, its IPv6 multicast routing table will include routes generated by these
protocols. The router chooses the optimal route from the IPv6 multicast routing table based on the
configured multicast routing and forwarding policy and installs the route entry into its IPv6 multicast
forwarding table.
RPF Check Mechanism
An IPv6 multicast routing protocol relies on the existing IPv6 unicast routing information or IPv6 MBGP
routes in creating IPv6 multicast routing entries. When creating IPv6 multicast routing table entries, an
IPv6 multicast routing protocol uses the reverse path forwarding (RPF) check mechanism to ensure IPv6
multicast data delivery along the correct path. In addition, the RPF check mechanism also helps avoid
data loops caused by various reasons.
RPF Check process
The basis for an RPF check is an IPv6 unicast route or an IPv6 MBGP route.
An IPv6 unicast routing table contains the shortest path to each destination subnet;