Hello Warren
Thanks for the clarification. When you have multiple equal-cost paths, by default, all multicast routing techniques will choose the PIM neighbor with the highest IP address. You can, however, configure multicast so that it dynamically advantage of multiple equal-cost paths using what is known as IP Multicast Load Splitting across Equal-Cost paths.
There are two methods to employ this:
- Enable ECMP multicast load splitting based on source address, source and group address, or based on source, group, and next-hop address. After the equal-cost paths are recognized, ECMP multicast load splitting operates on a per (S, G) basis, rather than a per-packet basis as in unicast traffic.
- Consolidate two or more equal-cost paths into a GRE tunnel and allow unicast routing to perform the load balancing.
I believe the first option is cleaner and more appropriate for your scenario. Take a look at the following Cisco documentation for more details of its operation as well as implementation.
I hope this has been helpful!
Laz