Reverse Path Forward (RPF) checking is a core multicast routing mechanism that 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.
For traffic arriving on the SPT, the expected incoming interface for a given source/group multicast flow is the interface towards the source address of the traffic (as determined by the unicast routing system.) For traffic arriving on the RP tree, the expected incoming interface is the interface towards the RP.
RPF override is an HPE networking feature that allows the override of the normal RPF lookup mechanism and indicates to the router that it may accept multicast traffic on an interface other than that which would be normally selected by the RPF lookup mechanism. This includes accepting traffic from a source directly connected to the router when the source IP address is invalid for the subnet or VLAN to which it is connected. Traffic may also be accepted from a valid PIM neighbor that is not on the reverse path towards the source of the received multicast traffic.
RPF checking is applied to all multicast traffic and is significant in preventing network loops. Up to eight manual RPF overrides can be specified.
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NOTE: These static RPF override entries are not distributed. |
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The manually configured static multicast RPF override is restored on subsequent reboots. The command is executed in PIM context.
Syntax:
Add, edit, or delete up to eight RPF override entries. The multicast RPF override has a multicast source address [source-ip-addr/mask-length
] and an RPF address [rpf-ip-addr
] pair.
The no
form of the command deletes the RPF override.
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NOTE: Only host-specific addresses are supported (i.e. “/32” addresses.) |
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