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Query about BFD Destination Address


I have read through IETF drafts and Cisco / Juniper documentation on BFD. However I am not clear on the following:

Lets say we have one-hop IP BFD configuration:


Lets say Asynchronous BFD mode is configured between R1 and R2 GigE interfaces.

I can see that BFD Control Packets are sent to UDP port 3784 but I am not able to understand what is the destination address used for the UDP packet ?

Especially in case of multi-vendor BFD, I have seen that some vendors use a unknown peer IP multicast address (like whereas some simply use the peer interface address as the destination address for these UDP packets.

Anyone has a clear idea and supporting evidence as to what is the standard for destination address to be used for UDP packets that are used for BFD ?

The reason I think it is important is because in a multi-vendor scenario, if a packet with an unknown destination address is received by the receiving peer, it may simply discard the BFD control packet without even looking into the UDP layer to determine if the packet is destined for the BFD-specific destination port of 3784 or not ??

Pls clarify.


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