ptmcast

With mcast you can easily implement your own IP multicast playout server. It implements its own IPv4/IPv6 stack, as well as its own IGMPv3/MLDv2 stack to be faster and more efficient as the built-in Linux stack.
On the other hand you can receive and intensively debug IP multicast distributions (MPEG-2 packetized transport streams).
The tool is made to be combined in a pipe with other Linux command line tools, either as stream grabber (input) or stream sender (playout) or even both.