H3C Technologies H3C S7500E Series Switches - Manual (Page 89)

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Figure 4-2 Changing an RPF route
As shown in Figure 4-2 , when no multicast static route is configured, Router C’s RPF neighbor
on the path back to Source is Router A and the multicast information from Source travels along
the path from Router A to Router C, which is the unicast route between the two routers; with a
static route configured on Router C and with Router B as Router C’s RPF neighbor on the path
back to Source, the multicast information from Source travels from Router A to Router B and
then to Router C.
Creating an RPF route
When a unicast route is blocked, multicast traffic forwarding is stopped due to lack of an RPF
route. By configuring a multicast static route for a given multicast source, you can create an
RPF route so that a multicast routing entry is created to guide multicast traffic forwarding.
Figure 4-3 Creating an RPF route
As shown in Figure 4-3 , the RIP domain and the OSPF domain are unicast isolated from each
other. When no multicast static route is configured, the hosts (Receivers) in the OSPF domain
cannot receive the multicast packets sent by the multicast source (Source) in the RIP domain.