Multicast Addressing
IP Multicast Group Addresses
 224.0.0.0–239.255.255.255
 Class “D” Address Space
 High order bits of 1st Octet = “1110”
TTL value defines scope and limits distribution
IP multicast packet must have TTL > interface TTL or it is discarded
values are: 0=host, 1=network, 32=same site, 64=same region,
128=same continent, 255=unrestricted
No longer recommended as a reliable scoping mechanism