Embedded-RP provides a way to assign a multicast router the Rendezvous Point (RP) role for a specific multicast group.
It’s a scalable solution for PIM-SM inter-domain multicasting.
For example, many RPs can be deployed anywhere on the Internet. It can also be used for intra-domain multicasting (although there are other solutions to consider for intra-domain multicasting).
It can't be used with Bidirectional PIM.
How it Works
An application indicates which router will assume the RP role by embedding the RP address within the multicast group address. The multicast routers then deduce the RP address by reading the multicast group address. There is no advertising RP information from one PIM-SM domain to another.
The benefit of Embedded-RP is that it enables us to do inter-domain multicasting.
Considerations of using Embedded-RP include:
- Careful planning - after all, we do need to embed a 128-bit RP address into a 128-bit multicast group address.
- No redundancy – Only one address can be embedded.
RP Addresses need to have many of the bits in the interface ID unused. In other words, the interface ID needs a lot of 0s. These unused bits will be used in the multicast group address for something else.
Let’s embed the following RP address into a multicast group address:
RP Address - 2001:CAFE:2222::8/128