IP Multicast (cont.)
A host may send IP multicast by using a multicast address as the destination address.
A host manages a table of groups and local application processes that belong to this group.
When a multicast message arrives at the host, it delivers copies of it to all of the local processes that belong to that group.
A host acts as a member of a group only if it has at least one active process that joined that group.
Extensions to IP inside a host: