Multicast Routing And Forwarding Configuration; Multicast Routing And Forwarding Overview; Introduction To Multicast Routing And Forwarding; Rpf Check Mechanism - HP 4800G Series Configuration Manual

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Multicast Routing and Forwarding Configuration

When configuring multicast routing and forwarding, go to these sections for information you are
interested in:

Multicast Routing and Forwarding Overview

Configuration Task List
Displaying and Maintaining Multicast Routing and Forwarding
Configuration Examples
Troubleshooting Multicast Routing and Forwarding
The term "router" in this document refers to a router in a generic sense or a Layer 3 switch running an IP
routing protocol.
Multicast Routing and Forwarding Overview

Introduction to Multicast Routing and Forwarding

In multicast implementations, multicast routing and forwarding are implemented by three types of
tables:
Each multicast routing protocol has its own multicast routing table, such as PIM routing table.
The information of different multicast routing protocols forms a general multicast routing table.
The multicast forwarding table is directly used to control the forwarding of multicast packets.
A 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
multicast protocols, its multicast routing table will include routes generated by multiple protocols. The
router chooses the optimal route from the multicast routing table based on the configured multicast
routing and forwarding policy and adds the route entry into its multicast forwarding table.

RPF Check Mechanism

A multicast routing protocol relies on the existing unicast routing information, MBGP routes, or multicast
static routes in creating multicast routing entries. When creating multicast routing table entries, a
multicast routing protocol uses the reverse path forwarding (RPF) check mechanism to ensure
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 a unicast route, an MBGP route, or a multicast static route.
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