Multicast Addressing
draft-albanna-iana-ipv4-mcast-guidelines-xx
http://www.iana.org/assignments/multicast-addresses
Examples of Reserved & Link-local Addresses
224.0.0.0 - 224.0.0.255 reserved & not forwarded
239.0.0.0 - 239.255.255.255 Administrative Scoping
224.0.0.1   - All local hosts
224.0.0.2   - All local routers
224.0.0.4   - DVMRP
224.0.0.5   - OSPF
224.0.0.6   - Designated Router OSPF
224.0.0.9   - RIP2
224.0.0.13 - PIM
224.0.0.15 - CBT
224.0.0.18 - VRRP