Multicast IP Addresses
Multicasts use the IP address range 224.0.0.0 to 239.255.255.255. The first
four bits of the first octet are always binary 1110, and the remaining 28 bits
identify the multicast group. Some addresses are reserved:
�¡ 224.0.0.1 is the all-hosts group.
�¡ 224.0.0.2 is the all-routers group.
�¡ The rest of the 224.0.0.0/24 range is reserved for link-local protocols.
�¡ 224.0.1.0 to 238.255.255.255 are for use over the Internet, and they are
called globally-scoped addresses.
�¡ Source-specific multicast uses 232.0.0.0/8 addresses.
�¡ 233.0.0.0/8 is used to assign static multicast addresses for use by an
organization. The second and third octets of the address are the organization�fs
Autonomous System number. This is called GLOP, which is a
combination of global and scope.
�¡ 239.0.0.0/8 is for local use within an organization, and it is called a
limited scope or an administratively scoped address.