I am a network engineer and was curious as to the best practice network setup for Ultra Messaging servers. Our company has an installation of Infomatica Ultra Messaging which facilitates several topics. The setup reuses a single multicast address for several topics with the distinct delineation of the topic being the Layer 4 port. Is it best to keep all the subscribers/publishers in the same subnet to facilitate multicast at Layer 2. Or, is it ok to have the severs located in different subnet (Layer 3) with the help of a Rendezvous Point. We are having a hard time with the setup where servers are separated by Layer 3 using the firewall as the gateway for the subnets and the RP location. Just looking for best practice documentation on how the servers should live on the network.