What would it take to setup a custom made multicast ip address in the network? Machines are linux. Let's say I want to have a multicast address with only some machines from the network as group members.
I suppose machines in the network should be added to the defined group, and some router should be configured?
Pick a multicast address, preferably from 239.255.0.0/16 range. Send from one machine on this address, then receive the stream on the other machines by joining the group from your application.
The network setup depends on whether your machines reside on many different VLANs or in the same. If all of them are on the same vlan and your switches have igmp snooping capabilities, you may need to setup the router for multicast routing so that igmp snooping works correctly or setup one of the switches as igmp querier.
If they are on multiple vlans you will have to setup proper multicast routing in your infrastructure eg PIM.
Avoid sending multicast traffic with TTL = 1, your gateway will not appreciate it. Also, do not send traffic to 224.0.0.xx addresses.
I recommend http://www.nrl.navy.mil/itd/ncs/products/mgen and wireshark for testing and understanding multicast.
