R211x-HP Flexfabric 11900 IP Multicast Configuration Guide

Figure 16 Changing an RPF route

As shown in Figure 16, when no static multicast route is configured, Switch C's RPF neighbor on the path

back to the source is Switch A, and the multicast data from the source travels through Switch A to Switch

C. When a static multicast route is configured on Switch C with Switch B as its RPF neighbor on the path

back to the source, the multicast data from the source travels along the path: Switch A to Switch B and

then to Switch C.

Creating an RPF route

When a unicast route is blocked, multicast forwarding might be stopped due to lack of an RPF route. In

this case, you can create an RPF route by configuring a static multicast route for a given multicast source,

so that a multicast routing entry is created to guide multicast forwarding.

Figure 17 Creating an RPF route

As shown in Figure 17, the RIP domain and the OSPF domain are unicast isolated from each other. When

no static multicast route is configured, the receiver hosts in the OSPF domain cannot receive the multicast

packets from the multicast source in the RIP domain. If you configure a static multicast route on Switch C

Receiver

Switch A

Switch B

Switch C

Vlan-int20

Vlan-int10

1.1.1.1/24

Multicast packets

Source

192.168.0.1/24

Receiver

Vlan-int10

1.1.1.2/24

Multicast static route

Source/Mask

Multicast Routing Table Static on Switch C

192.168.0.0/24

Interface

Vlan-int10

RPF neighbor/Mask

1.1.1.1/24