I have a somewhat unique application that uses Multicast for dozens of client devices to send data to a small group of servers.
The client devices use 239.192.1.1 as the destination IP, and the servers are members of this group. The servers are connected to a layer-2 switch. This switch connects to 2 switches (Cisco Catalyst
6500 and 3560) running IP routing and PIM sparse-mode Each router has an RP set. These switches each have a unique subnet behind them, with these client devices connected.
The problem I need help with is this, when I only have the clients on switch A powered on, multicast messages flow downstream towards the servers, through the layer 3 switch. When I power on the second group of devices on switch B, there seems to be an RP designated router 'election' to the switch with the higher IP on the server vlan. Once this happens the group of devices can no longer get their multicast messages forwarded thru switch A, only devices on switch B are able to do this until I shutdown the interfaces on the switches and bring up one side or the other only.
What I'm not sure of is if there is something I can do to keep both groups of client devices 'online' and sending messages to the same Multicast group via two separate paths.