The pair (multicast_address, port) should be unique to all servers and used to distinguish between servers.
The “server_name” parameter is the “friendly name” that the client software can use for display purposes. It doesn’t have to be unique, but it is generally recommended. Since data packets do not contain the server name, we cannot rely on this to distinguish between servers.
Using the sender IP address to distinguish between servers is possible but we do not recommend it as it would make difficult the implementation backup servers. For example, if a server goes down and a backup server takes his place, the sender IP would have to be changed on all clients (manually or with cues), which creates coupling between different systems.