Configuring RPF override

Configure Reverse Path Forward (RPF) override to allow the override of the normal RPF lookup mechanism, indicating to the router that it may accept multicast traffic on an interface other than the one that would normally be selected by the RPF lookup mechanism.

RPF checking ensures that multicast traffic received arrived on the expected router interface before it is considered for further processing. If the RPF check fails for a multicast packet, the packet is discarded.

RPF override entry gets precedence over routes learned from routing protocols or static routes. It must also be noted that PIM will not switch to an alternate path if the configured RPF neighbor is not reachable.

Prerequisites

You must be in the PIM configuration context, as indicated by the switch(config-pim)# prompt for IPv4 or the switch(config-pim6)# prompt for IPv6.

Procedure

Add, edit, or delete RPF overrides using the following command.

rpf-override <SRC-ADDR/SRC-MASK> <RPF-ADDR|INTERFACE-NAME>

For IPv4 configurations:

switch(config)# router pim
switch(config-pim)# rpf-override 40.0.0.4/24 30.0.0.4

For IPv6 configurations:

switch(config)# router pim6
switch(config-pim6)# rpf-override 50::4/24 tunnel1

NOTE:

When configuring rpf-override with <INTERFACE-NAME>, only 6in6 tunnel is supported for both IPv4 and IPv6 cases.